Srib_enodeb_features_description.pptx

SAMSUNG eNB FEATURES Prepared by: Samsung

Contents Call Control      

Extended Access Barring (SIB14) E-RAB Management X2 Interface Management Capacity based Call Admission Control Preemption CA Call Control

Mobility Control  Idle Mobility Support  S1 Handover  X2 Handover

Contents Services    

OTDOA Multicell and Multicast Coordination (MCE) eMBMS Session Monitoring eMBMS Service Restoration

Contents SON     

Intra-LTE ANR PCI Auto-Configuration RACH Optimization MLB MRO

System Test and Analysis  CSL (Call Summary Log) Report

LTE-SW0315, Extended Access Barring ( SIB14)

Call Control

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LTE-SW0315, Extended Access Barring (SIB14) INTRODUCTION  During network congestion, core Network will not be able to allocate backhaul resources for all UE's. So, an overload control mechanism is required. Extended Access Barring (EAB) bars low priority UE's such as MTC from accessing the network during RAN overload period. These UE's are affected by relatively lesser importance. To Support EAB, barring information is transmitted in SIB14 which is broadcasted to UEs. .

BENEFIT  Provides RAN overload control and overload control for shared RANs  Provides Core Network Overload Control..

DEPENDENCY & LIMITATION Dependency o Release 11 UE

Related Features o LTE-SW4105 Access Class Barring

LTE-SW0315, Extended Access Barring (SIB14) Table below shows UE categories in Different Releases of 3GPP

LTE-SW0315, Extended Access Barring (SIB14) Feature Description Due to diverse applications and services deployed in LTE network, there could be excess traffic resulting due to use of these applications and services. So, it is necessary to mitigate E-UTRAN access during peak traffic. The peak traffic could be from both core and access network. In case of core network, MME signaling or O&M can trigger E-UTRAN to initiate EAB (From TS 23.401 Section 4.3.17.2 Point (d)). Also, peak traffic could be reduced by refraining lowpriority UEs such as MTC devices to having access to eNB. 3GPP Release 11 features provides enhancements to GPRS to achieve this. This feature is Extended Access Barring.

LTE-SW0315, Extended Access Barring (SIB14)

During Peak Traffic, eNB reaches congestion state. The MME notifies to eNB about the congestion state. The eNB can initiate EAB when all MMEs connected to eNB request to restrict the load for UEs that are connected to the network with low access priority. It is achieved through OVERLOAD START message sent from MME to ENB. (From TS 23.401 Section 4.3.7.4.1).

LTE-SW0315, Extended Access Barring (SIB14) Dependency

o UE Acquires SIB14 when: o Upon receiving a PAGING message from eNB, identifies EAB Parameters modification. o If it does not have stored a valid version of SIB14 upon entering RRC_IDLE. The eNB should set SIB14 Flag as TRUE when sending SIB1 to indicate it as present. o

UE's access is denied if all the below mentioned conditions are true:

o UE belongs to access class (0- 9). oUE‟s category is same as the category received in SIB14. oUE's access class is same as access class received in SIB14.

LTE-SW0315, Extended Access Barring (SIB14)

The EAB is removed by eNB through SIB14 specifying as not Barred when eNB receives OVERLOAD STOP from MME. .

LTE-SW0315, Extended Access Barring (SIB14) SYSTEM OPERATION  How to Activate To change EAB activation, execute the CHG-SIB-INF/CHG-EAB-PARA command to configure the parameters (SIB 14).

 Key Parameters  CHG-SIB-INF/RTRV-SIB-INF

 CHG-EAB-PARA/RTRV-EAB-PARA

LTE-SW0315, Extended Access Barring (SIB14)

Counters and KPIs There are no related counters or KPIs.

LTE-SW0322, E-RAB Management

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LTE-SW0322, E-RAB Management INTRODUCTION  The ERAB is a bearer connection between eNB and Serving GW. The MME initiates E-RAB setup, modification, and release procedures, and it also can request eNB to modify E-RAB QoS characteristics. The eNB support all those procedures according to 3GPP TS36.413.  Once eNB and MME setup an E-RAB connection, eNB and S- GW can transmit user packets uplink and downlink through GTP tunnel. They distinguish each ERAB bearer by Tunnel Endpoint Identifier (TEID).

BENEFIT  The operator can provide EPS bearer service to its subscribers and manage ERAB resources for user data transport.

DEPENDENCY & LIMITATION o N/A .

LTE-SW0322, E-RAB Management FEATURE DESCRIPTION  The E-RAB setup procedure is used to add an E-RAB for a new service to a connected UE. The E-RAB for a new service can be added to the connected UE through E-RAB setup procedure. When receiving the E-RAB Setup Request message from MME, the eNB considers the current resource usage status and determines whether a new bearer can be added.  If a new E-RAB can be added, eNB performs the RRC Connection Reconfiguration procedure with UE for resource reconfiguration of the new DRB and transmits the E-RAB Setup Response message to MME.  Each E-RAB will have the following information: o E-RAB ID o The Transport Layer IP Address on the eNB o The eNB GTP Tunneling ID (TEID) for the eNB side. o QCI to assign session priority. o The maximum bit rate for the E-RAB. o Guaranteed bit rate for the eRAB.

LTE-SW0322, E-RAB Management o The E-RAB setup procedure is as follows:

LTE-SW0322, E-RAB Management E-RAB Modification Use the E-RAB modification procedure to change the QoS setting of a bearer (E-RAB) already in service. To use the E-RAB modification procedure, operator can change UE AMBR for non-GBR bearer and E-RAB Level QoS parameters (QCI, ARP and GBR QoS Information) for GBR bearer. The E-RAB modification procedure is as follows:

LTE-SW0322, E-RAB Management E-RAB Release  The E-RAB release procedure is used to release specific bearer service of a connected UE. This procedure is performed by request from MME. Also, MME requests E-RAB release based on its own decision (MME initiated E-RAB release) or as following action after an indication from eNB (eNB initiated ERAB release).

 When E-RAB RELEASE REQUEST message is received from MME, eNB performs RRC connection reconfiguration procedure with UE to release the corresponding DRB (data radio bearer). When the DRB is released successfully, eNB returns E-RAB RELEASE RESPONSE message to MME.

LTE-SW0322, E-RAB Management The E-RAB modification procedure is as follows:

LTE-SW0322, E-RAB Management SYSTEM OPERATION  How to Activate In case of standard QCI E-RABs, there is no additional activation procedure required but to activate operator specific QCIs, execute the CHG-QCI-VAL command to equip new QCIs to be used.

 Key Parameters  QCIs can be configured by executing the CHG-QCI-VAL command with following parameters:

LTE-SW0521, X2 Interface Management

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X2 Interface Management INTRODUCTION The X2 interface is used for direct communication of neighbor eNBs and handover between eNBs. The X2 interface has control plane and user plane. When a neighbor cell is added to eNB, the eNB automatically sets up X2 connection The X2 connection is a SCTP-based between eNBs in the X2 application layer.

BENEFIT The operator manages the signalling associations between eNBs, surveying X2 interface, and recovering from errors. Efficient usage of the radio resources can be provided.

X2 Interface Management DEPENDENCY AND LIMITATION Limitation Maximum 256 X2 connections are supported. The X2 based handover between Home eNBs is allowed if no access control at MME is needed.

FEATURE DESCRIPTION X2 AP Setup

X2 Setup The X2 AP setup procedure for unsuccessful case is as follows:

Samsung eNB2 sends X2 Setup failures to the eNB1 if: received PLMN is not supported or received ECGI is not eNB2's ECGI 1. 2.

The eNB1 receives the X2 setup failure message from eNB2. The eNB1 waits as long as Time To Wait as included in the X2 setup failure message and then resends the X2 setup request message to eNB2.

X2 Reset X2 AP Reset If an abnormal failure occurs with the X2 interface between two interacting eNBs, X2AP Reset procedure is performed to reconcile the resources between the two eNBs.

1 The eNB1 sends the X2 Reset Request message to eNB 2. 2 The eNB2 sends the X2 Reset Response message to eNB1. If there are any procedures which eNB 1 is carrying out via the X2 Interface, eNB2 stops all of them and performs the Call Release procedure for the call. Samsung eNB sends X2 Reset Request message to its neighbor eNBs when the cell of eNB is going to be released. If eNB1 could not receive X2 Reset Response message, it does not resend X2 Reset Request message and there is no further actions

Heartbeat Keep Alive between eNBs The eNB and neighbor eNB can monitor X2 connection by exchanging SCTP HEARTBEAT/ HEARTBEAT ACK messages defined by SCTP protocol. HEARTBEAT message is periodically transmitted and the period is configured as HEART_BEAT_INTERVAL. When transmitting HEARTBEAT message, eNB delivers the current time in the Heartbeat Information field, which is also included in the HEARTBEAT ACK message so that the sender and receiver can calculate the Round Trip Time (RTT). .

Heartbeat In case of SCTP connection is disconnected, all active calls will be disconnected. Note that idle mode UEs are not maintained in eNB and HERATBEAT message is defined by SCTP layer. . When HEARTBEAT ACK message is not received

SCTP Connection .

X2 Configuration SYSTEM OPERATION How to Activate Pre-condition SCTP connection is established and operational state is normal. Activation The NO_X2 value must be set to 'False'. Deactivation The NO_X2 value must be set to 'True'.

Key Parameters The maximum number of X2 neighbor eNB is 256 or 512. The following table shows the several system parameters of each neighbor eNB information:

CRTE-NBR-ENB/DLT-NBR-ENB/CHG-NBR-ENB/RTRV-NBR-ENB

X2 Configuration

X2 Configuration

SCTP Configuration The SCTP protocol manages using several system parameters for time interval of heartbeat message broadcast, re-broadcasting times of heartbeat or data message, and initial re-broadcast timeout value for Round Trip Time (RTO), minimum re-broadcast timeout value for RTO, maximum re-broadcast timeout value for RTO, and init message broadcast time interval for re-connection trial. Details are shown in below table. CHG-SCTP-PARA/RTRV-SCTP-PARA

X2 Status Monitoring SCTP and X2 state of neighbor eNB are possible using RTRVX2-STS command. The following table shows output information: . • NBR_ENB_ID: This parameter specifies the ID of the neighbor eNB. • SCTP_STATE: This parameter specifies the Stream Control Transmission Protocol (SCTP) status. It is the physical connection status between the eNBs. o disable_SD_PlmnTg_UA: shutdown by undecidable PLMN TGID. o disable_SD_PlmnVr: shutdown by undecidable PLMN VRID. o disable_SD_NoX2: shutdown by NO_X2 setting. o disable_SD_Locked: shutdown by administrative state locked setting. o disable_OOS: out of service (all case without above case). o enable_INS: in service.

• X2AP_STATE: This parameter specifies the X2AP status. It is the logical connection se retry count of X2 setup request is over than threshold. o disable_X2AP_RESET_TO: X2Ap status is disabled. Because retry count of X2 reset is over than threshold. o disable_X2AP_UPDATE_TO: X2Ap status is disabled. Because retry count of X2 update request is over than threshold. o disable_X2AP_SETUP_FAIL: X2Ap status is disabled. When X2 setup failure is received and x2 setup retry count was is 0(zero). o disable_X2AP_UPDATE_FAIL: X2Ap status is disabled. When X2 update failure is received and x2 update retry count is 0(zero). o enable_INS: in service.

X2 Communication Failure 1. Execute RTRV-X2-STS and check the state of the interface

Capture the wireshark logs of the interface and cross check whether SCTP messages are shared across (init, init_ack etc) the nodes. 1. If there is no SCTP message exchanged between the nodes, check the routing table and LAN configurations to ensure end to end link is functional. 2. If any of the above check points are not passed, then contact TAC3 System team for issue analysis. 3. Even if the above steps 2 and 3 are passed and no issues with SCTP (heart beat messages are successfully exchanged) then the issue could be with SCTB.

LTE-SW4101, Capacity based Call Admiss ion Control

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LTE-SW4101, Capacity based Call Admission Control INTRODUCTION The Call Admission Control (CAC) function is basically enabled to efficiently use the limited radio resources, to guarantee the quality of user service even in case of congestion, and to protect eNB system from being overloaded. There are three types of call admission control functionalities:  Capacity-based Call Admission Control  QoS-based Call Admission Control  Pre-emption

The Capacity-based CAC makes a decision based on the capacity that operator configures in advance. The QoS based CAC makes a decision based on the required QoS level and available radio resources of that time. The QoS based CAC has an effect only when MME requests GBR bearers. The Pre-emption allows a priority call. These three functionalities work at the same time.

LTE-SW4101, Capacity based Call Admission Control The operator can configure the capacity per cell and per eNB. To sustain a certain level of QoS for non-GBR services, operator can limit the maximum number of users allowed per cell. In addition, operator can configure the amount of resources that are reserved for incoming handover calls. In this case, the call admission algorithms make a decision based on the capacity that reflects the reserved resources. In case of no resources, emergency calls are allowed by pre-empting existing calls.

BENEFIT By limiting the maximum number UEs or bearers per cell and per eNB, considering radio and backhaul bandwidth, operator can control the minimum QoS level provided for UEs. The operator can protect the system from being shutdown due to overload or congestion

DEPENDANCY & LIMITATION N/A

LTE-SW4101, Capacity based Call Admission Control FEATURE DESCRIPTION Functional Architecture for CAC The Capacity based CAC operates on the RRC connection establishment and ERAB bearer establishment while QoS based CAC and Pre-emption has impact on E-RAB bearer establishment only. This feature covers capacity based CAC. In case of other two CAC features, refer to LTE-SW4102 and LTE-SW4103. The overall call admission control procedure is as follows:

LTE-SW4101, Capacity based Call Admission Control Capacity Based CAC The Capacity based CAC allows an incoming call or bearer as long as the total number of calls/bearers does not exceed the pre-configured thresholds per cell and eNB. There exist three kinds of thresholds: threshold for normal, threshold for emergency and handover user, and the maximum. These thresholds per eNB can be shown the figure below. Normal users can be allowed up to NOR_ENB_CALL_COUNT per eNB. Emergency and HO users can be allowed up to EM_HO_ENB_CALL_COUNT per eNB. These thresholds can be configured for CAC via LSM by using CALL_CAC_THRESH_FOR_NORMAL and CALL_CAC_THRESH_FOR_EMER_HO as follows: NOR_ENB_CALL_COUNT = MAX_ENB_CALL_COUNT * CALL_CAC_THRESH_FOR_NORMAL for the corresponding eNB. EM_HO_ENB_CALL_COUNT = MAX_ENB_CALL_COUNT * CALL_CAC_THRESH_FOR_EMER_HO for the corresponding eNB. .

LTE-SW4101, Capacity based Call Admission Control Also, there exist similar thresholds per cell as the figure below. Normal users can be allowed up to NOR_CELL_CALL_COUNT per cell. Emergency and HO users can be allowed up to EM_HO_CELL_CALL_COUNT per cell. These thresholds can be configured for CAC via LSM by using CALL_CAC_THRESH_FOR_NORMAL and CALL_CAC_THRESH_FOR_EMER_HO as follows: NOR_CELL_CALL_COUNT = MAX_CELL_CALL_COUNT * CALL_CAC_THRESH_FOR_NORMAL for the corresponding cell. EM_HO_CELL_CALL_COUNT = MAX_CELL_CALL_COUNT * CALL_CAC_THRESH_FOR_EMER_HO for the corresponding cell.

LTE-SW4101, Capacity based Call Admission Control In case of radio bearer, capacity-based CAC applies similar concept per cell as illustrated in the figure below. Bearers for normal users can be allowed up to NOR_DRB_CALL_COUNT per cell. Bearers for emergency and HO users can be allowed up to EM_HO_DRB_COUNT per cell. Theses thresholds can be configured for CAC by using DRB_CAC_THRESH_FOR_NORMAL and DRB_CAC_THRESH_FOR_EMER_HO as follows: NOR_CELL_CALL_COUNT = MAX_CELL_CALL_COUNT * CALL_CAC_THRESH_FOR_NORMAL for the corresponding cell. NOR_DRB_COUNT = MAX_DRB_COUNT * DRB_CAC_THRESH_FOR_NORMAL for the corresponding cell. EM_HO_DRB_COUNT= MAX_DRB_COUNT * DRB_CAC_THRESH_FOR_EMER_HO for the corresponding cell.

LTE-SW4101, Capacity based Call Admission Control eNB Capacity Based CAC Parameters In case of capacity concern, operator should consider the hardware platform and radio resources, for example, radio bandwidth, the number of channel card, and QoS level. The following table shows an example in case of 10 MHz bandwidth and the maximum values can be diverse in different channel card. The following table shows an example of system parameters configuration for capacity-based CAC. System parameter configuration can be different according to channel card and system bandwidth.

LTE-SW4101, Capacity based Call Admission Control Capacity Based CAC Operation This section describes capacity-based CAC operation in each call procedure: . Capacity Based CAC Operation at RRC Connection Establishment

LTE-SW4101, Capacity based Call Admission Control 1.

2.

During the RRC connection establishment, eNB capacity-based CAC operates per call. The procedure starts when the RRC connection request message is received from UE. The eNB capacity-based CAC procedure is initiated. Initially, the CAC operates at eNB level. If eNB level CAC is passed, cell level CAC proceeds. Detailed procedure can be described as follows:

eNB level CAC I.

II.

If the attempted RRC Connection is for normal user, NOR_ENB_CALL_COUNT is applied for the threshold. If the current number of UEs in the eNB is less than NOR_ENB_CALL_COUNT, eNB level CAC for the RRC Connection is passed. Otherwise, the call is rejected. If the attempted RRC Connection is for an emergency user, EM_HO_ENB_CALL_COUNT is applied for the threshold. If the current number of UEs in eNB is less than EM_HO_ENB_CALL_COUNT, eNB level CAC for the RRC Connection is passed. Otherwise, the call is rejected.

LTE-SW4101, Capacity based Call Admission Control Cell level CAC I.

II.

3.

If the attempted RRC Connection is for normal user, NOR_CELL_CALL_COUNT is applied for the threshold. If the current number of UEs in the cell is less than NOR_CELL_CALL_COUNT, eNB level CAC for the RRC Connection is passed. Otherwise, the call is rejected. If the attempted RRC Connection is for an emergency user, EM_HO_CELL_CALL_COUNT is applied for the threshold. If the current number of UEs in the cell is less than EM_HO_CELL_CALL_COUNT, eNB level CAC for the RRC Connection is passed. Otherwise, the call is rejected.

If the call is rejected and RRCConnectionReject is sent to UE, depriotisationReq IE can be populated according to the configuration.

LTE-SW4101, Capacity based Call Admission Control 3. 4.

5. 6.

If the call is rejected and RRCConnectionReject is sent to UE, depriotisationReq IE can be populated according to the configuration. If both eNB and cell level CAC is passed, RRC connection establishment is initiated by transmitting the RRC connection setup message to UE. If the call is rejected and the call type is an emergency call, the longest call among active calls in the cell is released. In case of a normal call, the RRC connection release message is transmitted to UE and the call is released. The UE transmits the RRC Connection Setup Complete message. The eNB sends MME Initial UE message

LTE-SW4101, Capacity based Call Admission Control Capacity Based CAC Operation at E-RAB Setup

After the RRC establishment, eNB capacity-based CAC operates by receiving the initial context setup request or E-RAB setup/modify request message from MME for the default radio bearer and dedicated radio bearer (DRB) setup.

LTE-SW4101, Capacity based Call Admission Control 1.

The eNB capacity-based CAC runs per E-RAB. o If the attempted bearer is for normal user, NOR_DRB_COUNT is applied for the threshold. If current number of bearers in the cell is less than NOR_DRB_COUNT, call is admitted. Otherwise, the call is rejected. o If the attempted bearer is for emergency user, EM_HO_DRB_COUNT is applied for the threshold. If current number of bearers in the cell is less than EM_HO_DRB_COUNT, call is admitted. Otherwise, the call is rejected.

2.

If the E-RAB is successfully admitted, the RRC connection reconfiguration message is transmitted to UE to initiate E-RAB (DRB) establishment.

3.

If the call is rejected, whether to admit the E-RAB is determined in interoperation with pre-emption function per E-RAB (DRB) to control the call flow (a partial success per E-RAB is ignored).

4.

The eNB sends MME E-RAB setup message.

LTE-SW4101, Capacity based Call Admission Control Capacity Based CAC Operation at Intra-eNB Handover

The eNB receives a measurement report from UE.

LTE-SW4101, Capacity based Call Admission Control 1.

When cell change take places within the same eNB, the eNB capacity-based CAC operates to control intra-eNB handover call admission.

2.

The eNB capacity-based CAC is initiated based on a call. If the current number of UEs in the cell is less than EM_HO_ENB_CALL_COUNT, the call is admitted. Otherwise, the call is rejected. If current number of bearers in the cell is less than EM_HO_DRB_COUNT, call is admitted. Otherwise, the call is rejected.

3.

If the call is admitted, the RRC connection reconfiguration message is transmitted to UE to initiate the intra-eNB handover. If the call is rejected, whether to admit the E-RAB is determined in interoperation with the preemption function per E-RAB (DRB) to control the call flow (a partial success per E-RAB is ignored).

4.

The UE transmits RRC connection reconfiguration complete message.

LTE-SW4101, Capacity based Call Admission Control Capacity Based CAC Operation at Inter-eNB Handover

LTE-SW4101, Capacity based Call Admission Control 1) The eNB receives a measurement report from UE. 2) The source eNB determines HO and sends the target eNBs a Handover Request message. 3) To control inter-eNB handover call admission, eNB capacity-based CAC operates by using the E-RAB Level QoS parameter included in the Handover Request message received. The eNB capacity-based CAC is initiated based on a call. If the current number of UEs in the cell is less than EM_HO_ENB_CALL_COUNT, call is admitted. Otherwise, the call is rejected. If current number of bearers in the cell is less than EM_HO_DRB_COUNT, call is admitted. Otherwise, call is rejected. 4) If call is admitted, the Handover Request Acknowledge message is transmitted to the source eNB to initiate the inter-eNB handover. If call is rejected, whether to admit the E-RAB is determined in interoperation with the pre-emption function per E-RAB (DRB) to control the call flow (a partial success per E-RAB is ignored) 5~6) The source eNB transmits the RRC connection reconfiguration message to UE and performs SN Status Transfer. 8~10) After path switch procedure, the target eNB sends Release Request to source eNB.

LTE-SW4101, Capacity based Call Admission Control SYSTEM OPERATION How to Activate Execute the RTRV-ENB-CAC command to retrieve eNB Call Admission Control. Execute the RTRV-CELL-CAC command to retrieve the Cell Call Admission Control. Execute the CHG-ENB-CAC command to configure the performance of the CAC function in the eNB unit. Execute the CHG-CELL-CAC command to configure the performance in the cell unit.

Key Parameters CHG-ENB-CAC/RTRV-ENB-CAC/CHG-CELL-CAC/RTRV-CELL-CAC

LTE-SW4101, Capacity based Call Admission Control Key Parameters CHG-ENB-CAC/RTRV-ENB-CAC/CHG-CELL-CAC/RTRV-CELL-CAC

CHG-RRCONNREJECTDEPRIO-INF/RTRV-RRCONNREJECTDEPRIO-INF

LTE-SW4101, Capacity based Call Admission Control CHG-TIME-INF/RTRV-TIME-INF

LTE-SW4103, Preemption

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LTE-SW4103, Preemption INTRODUCTION In case of no resource available, eNB can admit a new bearer by preempting existing bearers. This feature can be used to provide admission to priority users even in congestion. The decision is based on Allocation and Retention Priority (ARP) information of new bearer(s) and existing bearer(s). The ARP consists of priority level, preemption capability, and preemption vulnerability, which are delivered from MME to eNB during E-RAB establishment. When there are multiple preemptive candidate bearers, eNB selects a longest call. The MME has responsibility to configure appropriate ARP per each bearer.

BENEFIT The operator can provide a differentiated service that allows a high-priority UE to access the network even in congestion.

DEPENDANCY & LIMITATION Dependency MME to support this feature

LTE-SW4103, Preemption Limitation A connected UE could experience a call drop when eNB is congested. Related Features LTE-SV0101 IMS based Emergency LTE-SV0105 eMPS LTE-SW4101 Capacity based CAC LTE-SW4102 QoS based CAC

FEATURE DESCRIPTION Functional Architecture for CAC The Capacity based CAC has impact on RRC connection establishment and ERAB bearer establishment while QoS based CAC and Pre-emption has impact on E-RAB bearer establishment only. This section covers preemption. In case of other two CAC features, refer to LTE-SW4101 and LTE-SW4102.

LTE-SW4103, Preemption The functional architecture of Call Admission Control (CAC) is as follows:

LTE-SW4103, Preemption

LTE-SW4103, Preemption Handover of Preempted UE The following flowchart shows operation flow before the CAC pre-emption handover function executes:

LTE-SW4103, Preemption The CAC pre-emption handover function is as follows:

LTE-SW4103, Preemption SYSTEM OPERATION How to Activate The operator can enable the preemption function by setting PREEMPTION_FLAG to USE by executing the CHG-CELL-CAC command. When this function is disabled, eNB ignores the ARP information received from MME and it does not admit a new bearer when the configured maximum number of bearers is all used. The operator can also enable the preemption handover function by setting ACTIVE_STATE to ACTIVE by executing the CHG-PREEMPT-HO command.

Key Parameters CHG-CELL-CAC/RTRV-CELL-CAC

LTE-SW4103, Preemption CHG-PREEMPT-HO/RTRV-PREEMPT-HO

LTE-SW5500, CA Call Control

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LTE-SW5500, CA Call Control INTRODUCTION The Carrier Aggregation (CA) is LTE-Advanced key feature that enhances the peak throughput and quality of UE by allowing UE to use two or more carrier resources simultaneously. According to 3GPP standard, single UE may aggregate up to 5 carriers and 100 MHz frequency bandwidth at the same time. Due to this feature, eNB performs the following functions:  Selection of secondary cells (SCells)  Decision on the allowance of SCell addition  Delivery of the L1 and L2 configuration information for SCells

The basic call processing procedures such as UE Context Setup and Handover are upgraded to support the aforementioned functions.

BENEFIT The operator can enhance the utilization of frequency resource and obtain load balance effects, and more for scheduling. The UE can improve throughput and reduce file download delay.

LTE-SW5500, CA Call Control DEPENDANCY & LIMITATION Dependency Rel 10 UE that supports carrier aggregation Depending on the standard, up to 5 carriers per UE can be aggregated.

FEATURE DESCRIPTION The eNB supports two following operating modes to effectively support the CA development scenario of 3GPP Rel10 TS36.300 Annex J:

LTE-SW5500, CA Call Control

Mode 1: When UE establishes RRC-connection to PCell or is handed over to PCell, eNB directs UE to add the SCell collocated to the PCell. The UE does not measure L3 radio quality of SCell. Mode 2: When UE establishes RRC-connection to PCell or is handed over to PCell, eNB directs UE to add the SCell collocated to the PCell. The UE may release and add the SCell again according to L3 measurement report of the SCell. Check Blocks for SCell Addition  Samsung eNB considers the following conditions for adding SCell:

LTE-SW5500, CA Call Control

C4 Checking is moved to SCell activation stage.

LTE-SW5500, CA Call Control Basic Operation for CA. At the Setup of Initial Context Setup (Mode 1, 2) The eNB performs checks in serial order to determine the CA availability on obtaining UE capability (at the reception of initial context setup request or of UE capability information), C1. PCell CA ON/OFF Check C3. CA Band Capability Check C5. SCell Availability Check If the conditions C1 and C3 are met according to the CA operation modes, eNB sends the following configurations in the RRC Connection Reconfiguration message transmitted to UE in the conventional setup procedures. In case of Mode 1, If C5 is satisfied for the paired SCell, the eNB configures UE to add the paired SCell that meets C3 condition.

LTE-SW5500, CA Call Control In case of Mode 2, If C5 is satisfied for the paired SCell, o The eNB configures UE to add paired SCell that meets C3 condition o Configures the event A2 measurement for SCell release. If neither of conditions is failed, eNB performs the conventional initial context setup procedure, that is, UE does not perform any other CA-related operations. Once completing UE context setup, even if the states of C1 to C5 are changed from the 'CA unavailable' to 'CA available' before the release of RRC Connection or the handout to other cells, the current SCell and SCell measurement configuration are not changed. As ever, even if the conditions C1 to C5 during RRC connection are changed 'the CA available' state to 'CA impossible' state, eNB does not perform SCell release nor measurement configuration.

LTE-SW5500, CA Call Control On Receiving Event A4 Measurement for SCell Addition Trigger (Modes 2) Before eNB receives Event A4 Measurement Report (MR) for SCell addition, UE is supposed to have no added SCell at the SCC. The eNB performs the following in serial order for the neighbor cell triggering the event on receiving Event A4 MR for SCell addition trigger: C6. Co-Schedulability Check C5. SCell Availability Check If all conditions C6 and C5 are satisfied, eNB sends UE a separate RRCConnectionReconfiguration message to set the following: In case of Mode 2, Add the reported neighbor cell triggering Event A4 as SCell Release event A4 measurement on SCC of the added SCell Configure the event A2 measurement for releasing SCell whose SCC of the added SCell is Measurement Object (MO).

LTE-SW5500, CA Call Control On Receiving Event A2 MR for SCell Release Trigger (Modes 2) On receiving event A2 MR for SCell release trigger, eNB sends to UE a separate RRCConnectionReconfiguration message for UE to set the following:  SCell release in SCC corresponding to MO of the triggered event A2  Release of event A2 measurement for SCell release at SCC of the released SCell is MO  Configuration of event A4 measurement for SCell addition at SCC of the released SCell is MO

On Receiving RRC Connection Re-establishment The eNB performs the following just after receiving the RRCConnectionReestablishment message from the UE: Release of all SCells configured. After completes the RRC connection REestablishment (RRE) procedure, the configuration related to the CA on the RRCConnectionReconfiguration message is performed as same as the RRC connection establishment.

LTE-SW5500, CA Call Control Operation at Intra-eNB Handover If CA supporting eNB receives a HO event MR and the neighbor cell triggering the event is a cell belongs to eNB includes the PCell, the following check operations are performed in serial order to determine CA availability in the target cell: C1. PCell CA ON/OFF Check C3. CA Band Capability Check C6. Co-Schedulability Check C5. SCell Availability Check Based on the conditions according to the CA operating modes, eNB adds the following configurations in the RRCConnectionReconfiguration message including MobilityControlInfo.

LTE-SW5500, CA Call Control In case of Mode 1, If all conditions C1 and C3 are satisfied, and C5 is satisfied for the paired SCell, UE is configured to add the paired SCell on the SCC. In case of Mode 2, If all conditions C1 and C3 are passed, and C5 is satisfied for the paired SCell, UE is configured to add the paired SCell on the SCC. The eNB configures event A2 measurement for SCell release at SCC of the added SCell is MO.

LTE-SW5500, CA Call Control Operation at Inter-eNB Handover (X2, S1 HO) Operation of Source eNB In inter-eNB HO procedure, the source eNB sends the target eNB the S1AP or X2AP:

Handover Request message includes the follows: Serving SCell list (sCellToAddModList) set by the source eNB CandidateCellInfoList on the serving frequencies UE-RadioAccessCapability

LTE-SW5500, CA Call Control Operation of Target eNB When the target eNB supporting CA receives the S1AP or X2AP: Handover Request message from the source eNB, it performs the following check operations in serial order to determine the CA availability of UE from the source eNB:     

C1. PCell CA ON/OFF Check C3. CA Band Capability Check C6. Co-Schedulability Check C5. SCell Availability Check C8. UE FGI bit 112 Check

If all conditions C1 to C3 are satisfied, eNB configures as followings:

LTE-SW5500, CA Call Control In case of Mode 1, If C5 is satisfied for the paired SCell, eNB configures UE to add paired SCell that meets C3.

In case of Mode 2, If C5 is satisfied for the paired SCell, eNB configures UE to add paired SCell that meets C3. The eNB configures event A2 measurement for SCell release at SCC on which the SCells are added. When UE unsatisfied C8 performs S1 HO, and the handover type described in the S1AP: Handover Required message is either of the following cases, the target eNB does not include the configuration of SCell addition nor measurement for searching SCell in the Handover Request Acknowledge message, but configures one more separate RRC Connection Reconfiguration message after completion of the handover of UE.  UTRAN to LTE  GERAN to LTE

LTE-SW5500, CA Call Control Additional Feature: PCell Frequency Switching. Merits PCell Frequency Switching enables SCell-configured UEs to perform interfrequency handover to the SCC earlier than UEs not configuring SCell, thereby SCell-configured UEs can maintain a higher throughput level compared to nonCA UEs. In addition, PCell Frequency Switching is free from PCell throughput degradation caused by measurement gap since CA UEs with a configured SCell can measure L3 channel quality of neighbor cells on the SCC without measurement gap.

Setting of Related Parameters Event A2/A1 thresholds for SCell-configured UEs to trigger inter frequency searching are defined as configurable system parameters, which shall be set to higher values than those for non-CA UE. Event A3 offset/A5 threshold2 for SCell-configured UEs to trigger inter frequency handover are defined as configurable system parameters, which are recommended to set the same or higher values than those for non-CA UEs.

LTE-SW5500, CA Call Control Operation On meeting event-triggering conditions for SCell-configured UEs, SCellconfigured UEs perform inter frequency searching and inter frequency handover to the SCC. The following figures show state transition diagram of SCell configuration and measurement configuration in PCell Frequency Switching  CA_InterF_: Threshold or offset for SCell-configured UEs to trigger interfrequency carrier searching or handover  InterF_: Threshold or offset for non-CA UEs (including CA UEs which do not have SCell added) to trigger inter-frequency carrier searching or handover Mode 1. Operation Details This section describes how measurements are managed in Mode 1.

As described earlier, the SCell is added in Mode 1 at the time of RRC Connection Reconfiguration (if not already added). Along with the SCell addition, the CA_InterF_A2 event is configured for PCell. This event is used to monitor PCell level and trigger further measurements. It should be defined higher than regular A2 measurements. CA_InterF_A2 is again added.

LTE-SW5500, CA Call Control When the CA_InterF_A2 trigger is reported, eNB configures CA_InterF_A1 (on PCell), CA_InterF_A3/A5, and InterF_A2 (on PCell). If UE reports CA_InterF_A1, other measurement triggers are removed and If UE reports InterF_A2, eNB configures InterF_A1 and InterF_A3/A5 on UE and removes other measurements. If UE reports CA_InterF_A3/A5 (for SCell FA), eNB performs a PCell switch in which the SCell FA becomes the new PCell and the previous PCell FA is added as the new SCell. If UE reports InterF_A1, eNB removes the existing measurements and adds CA_InterF_A1 (on PCell), CA_InterF_A3/A5, and InterF_A2 (on PCell). If UE reports InterF_A3/A5, a regular handover is performed.

LTE-SW5500, CA Call Control Mode 1. Operation Details Mode 2 operates similarly to Mode 1 except that A2 measurements related to SCell addition and release are also added.

Limitation PCell Frequency Switching does not apply to UEs having GBR bearer(s).

LTE-SW5500, CA Call Control SYSTEM OPERATION How to Activate Execute the CHG-CACELL-INFO command to configure CA_AVAILABLE_TYPE to DL_Only.

Key Parameters CHG-CACELL-INFO/RTRV-CACELL-INFO

LTE-SW1002, Idle Mobility Support

Mobility Control

85

LTE-SW1002, Idle Mobility Support INTRODUCTION To support intra-LTE cell reselection, eNB broadcasts the System Information Block type 3 (SIB3), System Information Block type 4 (SIB4), and System Information Block type 5(SIB5). The UE shall monitor E-UTRAN BCCH during idle mode to retrieve these SIBs for the preparation of intra-LTE cell reselection. Then, UE makes measurements on neighbouring cells based on the criteria and performs cell reselection to intra-/ inter-frequency neighbouring cells when needed. The parameters for intra-LTE cell reselection broadcasted in SIB3, SIB4, and SIB5 are as follows:  SIB3 conveys the common information for intra-frequency, inter-frequency and/ or inter-RAT cell reselection.  SIB3 also conveys the specific information for intra-frequency cell reselection.  SIB4 conveys the intra-frequency neighbouring cell related information, that is, intra-frequency neighbour cell list and blacklisted cells.  SIB5 conveys the specific information for inter-frequency cell reselection.

LTE-SW1002, Idle Mobility Support BENEFIT The operator can provide idle mobility to its subscribers within E-UTRAN. The LTE users in idle state can be moving within E-UTRAN.

DEPENDENCY AND LIMITATION N/A

FEATURE DESCRIPTION PLMN Selection When LTE UE is switched ON, it will start a process to find Public Land Mobile Network (PLMN). The PLMN may be selected either automatically or manually, depending on the device's configuration.

LTE-SW1002, Idle Mobility Support Based on the request from NAS layer of UE, if a required PLMN is already associated with LTE, UE shall scan LTE carriers based on UE stored information. The UE shall search for the strongest PLMN cell and tune to the Physical Downlink Shared Channel (PDSCH to read SIB1(s), where PLMN information is delivered. The PLMN which is reported to NAS shall have its measured RSRP value. Once PLMN (high quality or otherwise) is selected, UE access stratum will be instructed to measure reference signal and read the PDSCH for SIB1. This process occurs again to initiate cell selection using the S-Criteria (based on Q_RX_LEV_MIN). At this stage if the S-criteria is not met, UE will go into limited service (for emergency calls) or will find an equivalent PLMN. The following figure shows the idle mode state procedure:

LTE-SW1002, Idle Mobility Support Limitation Standardization of this feature is ongoing in 3GPP release 12, hence schedule and operation is subject to change.

FEATURE DESCRIPTION To allow UE to skip Access Class Barring for specific application such as mobile originating MMTELVoice, MMTELVideo, or SMS, eNB can broadcast 3 ACB skip indicators in SIB2 under system configuration. When UE tries to establish RRC connection for specific application, UE checks relevant ACB skip indicator and skips ACB and consider access to the cell as not barred if ACB skip indicator for relevant application is set. The following figure shows ACB skip operation for a mobile originating MMTELVoice:

LTE-SW1002, Idle Mobility Support Selected PLMN available/unavailable: The UE scans all RF channels in EUTRAN band according to its capabilities to find available PLMNs. Not camped: No suitable cell found. Camped normally: The UE obtains normal service and performs the following tasks:  Select and monitor the PCH of the cell.  Performs system information monitoring.  Perform necessary measurements for the cell reselection evaluation procedure.

Execute the cell reselection evaluation procedure. Camped on any cell: The UE obtains limited service and periodically searches for a suitable cell in the selected PLMN, if UE supports. Cell selection: The UE selects a suitable cell and the radio access mode based on idle mode measurements and cell selection criteria. Cell reselection: If after cell reselection evaluation process a better cell is found, the cell reselection is performed. If no suitable cell is found, UE enters to the next state 'Any cell selection'. Any cell selection: The UE searches an acceptable cell of any PLMN to camp on

LTE-SW1002, Idle Mobility Support The following table shows the parameters for PLMN selection:

Cell Selection Initial Cell Selection The following figure shows initial cell selection procedures:

LTE-SW1002, Idle Mobility Support The UE scans all RF channels in E-UTRAN bands to its capability to find acceptable cells, which are not barred and measure RSRP value greater than or equal to -110 dBm. To read PLMN identity and decide the availability of the cell, UE shall detect Primary/Secondary synchronization signals (PSS/SSS) and decode cell specific reference signal (CRS) and read at least MIB and SIB1. PCID should not be overlapped between adjacent cells for successful detecting and decoding of the signals. The PLMN reading will be reported to NAS layer, and the search for PLMNs may be stopped on request of NAS. Once UE has selected the PLMN, the cell selection procedure shall be performed to select a suitable cell of that PLMN to camp on to access available services, as described in TS36.304. If UE has stored information of carrier frequencies and also (optionally) information on cell parameters from previously received measurement, UE can use this information to speed up the selection procedure.

LTE-SW1002, Idle Mobility Support The suitable cell should satisfy that:  The cell is not barred  The cell is part of the selected PLMN or the registered PLMN or a PLMN of an equivalent PLMN list  The cell is part of at least one TA that is nor port of the list of 'forbidden tracking areas for roaming'  The cell selection criterion S satisfies that Srxlev > 0 AND Squal > 0

Priorities between different frequencies or RATs provided to UE by system information or dedicated signaling are not used in the cell selection procedure. Cell Barring The LTE E-UTRAN cells broadcast cell selection information through SIB1 and SIB2 (AC-Barring). SIB1 has two fields for cell status indication:  cellBarred  cellReservedForOperatorUse

LTE-SW1002, Idle Mobility Support cellBarred is common for all PLMNs and cellReservedForOperatorUse is specific per PLMN. When cell status is indicated as 'not barred' and 'not reserved' for operator use, all UEs shall treat this cell as candidate during the cell selection and cell reselection procedures. When cell status is indicated as 'not barred' and 'reserved' for operator use for any PLMN, The UEs assigned to Access Class 11 or 15 operating in their HPLMN/EHPLMN shall treat this cell as candidate during the cell selection and reselection procedures if the field cellReservedForOperatorUse for that PLMN set to 'reserved'. The UEs assigned to an Access Class in the range of 0 to 9, 12 to 14 shall behave as if the cell status is 'barred' in case the cell is 'reserved for operator use' for the registered PLMN or the selected PLMN. When cell status 'barred' is indicated or to be treated as if the cell status is 'barred', UE is not permitted to select/reselect this cell, not even for emergency calls.

LTE-SW1002, Idle Mobility Support Cell Selection Criteria The cell selection is performed on the detected cell with RX signal and decoded MIB and SIBs. Cell selection criteria: Srxlev > 0 AND Squal > 0 Where, Srxlev = Qrxlevmeas - (Q_RX_LEV_MIN + Q_RXLEV_MIN_OFFSET) Pcompensation, Squal = Qqualmeas - (Q_QUAL_MIN + Q_QUAL_MIN_OFFSET)

The following table shows the parameters of cell selection criteria:

LTE-SW1002, Idle Mobility Support

Since Q_QUAL_MIN and Q_QUAL_MIN_OFFSET are not provided in network, devices will test Srxlev only. If q-QualMinWB (in SIB1/SIB3/SIB5) is present, UE shall, when performing RSRQ measurement, use a wider bandwidth.

LTE-SW1004, S1 Handover

Mobility Control

97

LTE-SW1004, S1 Handover INTRODUCTION S1 handover is mobility control functionality between two adjacent eNBs using S1 interface with MME (inter-eNB handover via S1 interface). S1 handover is used when there is no available direct interface with target eNB, or target eNB belongs to another MME group.

BENEFIT The operator can provide connected mobility to its subscribers between cells in different eNBs. Users in a connected state can be moving within E-UTRAN, with change of serving cell.

DEPENDENCY AND LIMITATION Limitation With Full Configuration, Hyper Frame Number (HFN) is reset for all bearers and lossless HO is not supported.

LTE-SW1004, S1 Handover FEATURE DESCRIPTION The following figure shows the S1 handover procedure in E-UTRAN (S1 handover with MME and S-GW relocation case):

LTE-SW1004, S1 Handover

1) The UE sends MEASUREMENT REPORT including E-UTRAN measurements to the source eNB 2) 2) The source eNB determines whether to perform S1-based handover into the target eNB. This decision can be initiated if there is no X2 connection to target eNB or inter-eNB handover of target eNB is configured to execute the S1 handover.

LTE-SW1004, S1 Handover Handover decision in case of PCI duplication: On reception of MR message, eNB checks whether PCI from MR exists in Neighbor NRT or not. If there are several NRs with same PCI (this case is called PCI duplication), then eNB requests UE for measurement with the purpose set to report CGI. After obtaining MR message including ECGI, eNB triggers Handover Preparation using NR of the reported ECGI. 3) The source eNB sends HANDOVER REQUIRED to source MME. The source eNB provides information about which bearer is used for data forwarding and whether direct forwarding is possible from source eNB to target eNB. 4) 4)~6) The MME transmits the HANDOVER REQUEST message to target eNB. This message creates UE context which has bearer related information and security context in the target eNB. 7) The target eNB transmits the HANDOVER REQUEST ACKNOWLEDGE message to MME 8) 8)~10) If indirect forwarding is used, MME transmits the Create Indirect Data Forwarding Tunnel Request message to S-GW. The S-GW replies to MME with the Create Indirect Data Forwarding Tunnel Response message. 11) The source eNB receives the HANDOVER COMMAND from source MME.

LTE-SW1004, S1 Handover 12) The source eNB creates the RRCConnectionReconfiguration message using the Target to Source Transparent Container IE included in the HANDOVER COMMAND message and transmits it to UE. To transmit the PDCP status and the HFN status of the E-RABs of which the PDCP status must be preserved, source eNB transmits eNB/MME STATUS TRANSFER message to target eNB via MME. The source eNB must start forwarding downlink data to target eNB through the bearer, which is planned to be used for data forwarding. This can be either direct or indirect forwarding. The UE performs synchronization to target eNB and connects to target cell through RACH. The target eNB replies with UL allocation and timing advance. 13) After successful synchronization with the target cell, UE notifies the target cell that the handover procedure is complete using the RRCConnectionReconfigurationComplete message. The downlink packet forwarded from source eNB can be transmitted to UE. The uplink packet can be transmitted to S-GW from UE through target eNB 14) 14)~16) The target eNB sends a HANDOVER NOTIFY message to MME to inform that UE has changed cell. 17) 17~18) The MME transmits the Modify Bearer Request message to S-GW per each PDN connection.

LTE-SW1004, S1 Handover The downlink packet from S-GW is immediately transmitted to target eNB. 19) The S-GW transmits the Modify Bearer Response message to MME. To support packet re-arrangement in target eNB, S-GW transmits at least one „end marker‟ packets to the previous path as soon as the path is changed. 20) If any of the conditions listed in Section 5.3.3.0 of TS 23.401 (6) is met, UE starts the Tracking Area Update procedure. 21)~24) The source MME releases UE‟s resources that was used in the source eNB and the resources for data forwarding. Full Configuration :The full configuration option is used to support EUTRA handover to eNB of an earlier release. The target uses a full configuration and previous configuration is discarded by UE. This can lead to a change in RLC mode for a bearer and the operation for RLC AM is the same as that for RLC UM. HFN is reset for all bearers. Since source eNB may not be aware that target eNB is using full configuration, there is no difference in source eNB behaviour. The target eNB does not resend data that was attempted delivery to UE to prevent data duplication. using new configuration.

LTE-SW1004, S1 Handover The source eNB includes ue-ConfigRelease IE in HandoverPreparationInformation message, ue-ConfigRelease IE indicates the RRC protocol release used for UE specific dedicated configuration. If target eNB does not support the release of RRC protocol which source eNB used to configure UE, target eNB may be unable to comprehend UE configuration provided by source eNB. In this case, target eNB should use the full configuration option to reconfigure UE for Handover and Re-establishment. Full configuration option includes an initialization of the radio configuration, which makes the procedure independent of the configuration used in the source cell with the exception that the security algorithms are continued for the RRC re-establishment. In case of reconfigurations involving the full configuration option, the PDCP entities are newly established (SN and HFN do not continue) for all DRBs irrespective of the RLC mode. The UE deletes current configuration and applies new configuration based on the configuration provided by target eNB. Security configuration is retained and security algorithm is retained for re-establishment. SRBs are reconfigured. DRBs are released and re-setup using new configuration.

LTE-SW1004, S1 Handover SYSTEM OPERATION How to Activate  Select 1 event to use to activate S1 Handover.  ACTIVE_STATE of CHG-EUTRA-A3CNF with PURPOSE A3PurposeIntraLteHandover set to active or ACTIVE_STATE of CHG-EUTRA-A5CNF with PURPOSE A5PurposeIntraLteHandover set to active  A3 event is preferred.  Set NO_HO of CHG-NBR-ENB to false. It is controlled by NBR eNB base.

Key Parameters CHG-EUTRA-A3CNF/RTRV-EUTRA-A3CNF

LTE-SW1004, S1 Handover CHG-EUTRA-A5CNF/RTRV-EUTRA-A5CNF

LTE-SW1004, S1 Handover

CHG-NBR-ENB/RTRV-NBR-ENB/CRTE-NBR-ENB/DLT-NBR-ENB

LTE-SW1005, X2 Handover

Mobility Control

108

LTE-SW1005, X2 Handover INTRODUCTION  X2 handover is a handover between two adjacent eNBs using X2 interface (inter eNB handover via X2 interface).  X2 based handover is used when:  There is an available direct interface with the target eNB  The target eNB belongs to the same MME group.

BENEFIT  The operator can provide connected mobility to its subscribers between cells in different eNBs.  Users in a connected state can be moving within E-UTRAN, with change of serving cell.

DEPENDENCY AND LIMITATION Limitation  With Full Configuration, HFN is reset for all bearers and lossless HO is not supported.

LTE-SW1005, X2 Handover FEATURE DESCRIPTION  When eNB receives a measurement report including Event A3 from UE, eNB triggers intra-LTE handover to the best cell indicated in the measurement report. Because handover target cell is decided by UE‟s measurement results for neighboring cells.  The eNB can transit from X2 handover to S1 handover with direct forwarding, when X2 setup fail (cause: 'Invalid MME Group ID').  The following figure shows the X2 handover procedure in E-UTRAN:

LTE-SW1005, X2 Handover

LTE-SW1005, X2 Handover 1) 2)

3) 4)

The UE sends MEASUREMENT REPORT including E-UTRAN measurements to the source eNB. The source eNB determines whether to accept UE based on the Measurement Report message and radio resource management information. Handover decision in case of PCI duplication: On reception of MR message, eNB checks whether PCI from MR exists in Neighbor NRT or not. If there are several NRs with same PCI (this case is called PCI duplication), then eNB requests UE for measurement with the purpose set to report CGI. After obtaining MR message including ECGI, eNB triggers Handover Preparation using NR of the reported ECGI. The source eNB transmits the HANDOVER REQUEST message and the information necessary for handover to target eNB. The target eNB performs admission control for the incoming handover request. If accepted, target eNB prepares the handover and creates the RRCConnectionReconfiguration message including the mobilityControlInfo IE that communicates the source eNB to perform the handover. The target eNB includes the RRCConnectionReconfiguration message in the HANDOVER REQUEST ACKNOWLEDGE message and transmits it to the source eNB. Bearer Setup list includes a list of tunnel information for receiving forwarded data if necessary.

LTE-SW1005, X2 Handover 5) The RRC CONNECTION RECONFIGURATION for handover is constructed by the serving eNB and is sent to UE. To send the uplink PDCP SN receiver status and the downlink PDCP SN transmitter status of the E-RABs of which the PDCP status must be preserved, the source eNB sends the SN STATUS TRANSFER message to target eNB. After receiving the RRCConnectionReconfiguration message that includes the mobilityControlInfo IE, UE performs synchronization with target eNB and connects to target eNB through the Random Access CHannel (RACH). The target cell replies with UL allocation and timing advance. 6) The UE performs the handover to target cell. After UE has successfully synchronized to target cell, it sends a RRC CONNECTION RECONFIGURATION COMPLETE message to the target cell. 7) The target eNB sends a PATH SWITCH REQUEST message to MME to inform that UE has changed cell. 8)~10) The MME sends the Modify Bearer Request message to S-GW. The S-GW changes the downlink data path into the target eNB. The S-GW transmits at least one 'end marker' to source eNB through the previous path and releases the user plane resource for source eNB. 11) The S-GW transmits the Modify Bearer Response message to MME. 12) The MME returns the PATH SWITCH ACKNOWLEDGE message to target eNB.

LTE-SW1005, X2 Handover 13) The target eNB sends the UE CONTEXT RELEASE message to source eNB to notify handover has succeeded and to make source eNB release its resources. If source eNB receives the UE CONTEXT RELEASE message, it releases the radio resources and the control plane resources related to UE context. 14 If S-GW is relocated, MME releases UE‟s resource that is used in the source S-GW. Enhancement The full configuration option is used to support EUTRA handover to eNB of an earlier release. The target uses a full configuration and the previous configuration is discarded by UE. This can lead to a change in RLC mode for a bearer and the operation for RLC AM is the same as that for RLC UM. HFN is reset for all bearers. Since source eNB may not be aware that target eNB is using full configuration, there is no difference in source eNB behaviour. The target eNB does not resend data that was attempted delivery to UE to prevent data duplication.

LTE-SW1005, X2 Handover  Samsung eNB (LTE) Feature Description for PKG 5.0.0 v2.0 170 © Samsung Proprietary and Confidential  The Source eNB includes ue-ConfigRelease IE in HandoverPreparationInformation message, ue-ConfigRelease IE indicates the RRC protocol release used for UE specific dedicated configuration. If target eNB does not support the release of RRC protocol which source eNB used to configure UE, target eNB may be unable to comprehend UE configuration provided by source eNB. In this case, target eNB should use the full configuration option to reconfigure UE for Handover and Re-establishment. Full configuration option includes an initialization of the radio configuration, which makes the procedure independent of the configuration used in the source cell with the exception that the security algorithms are continued for the RRC re-establishment. In case of reconfigurations involving the full configuration option, the PDCP entities are newly established (SN and HFN do not continue) for all DRBs irrespective of the RLC mode.  The UE deletes current configuration and applies new configuration based on the configuration provided by target eNB. Security configuration is retained and security algorithm is retained for re-establishment. SRBs are reconfigured. DRBs are released and re-setup using new configuration.

LTE-SW1005, X2 Handover  The general message flow is as follows:

LTE-SW1005, X2 Handover 1 The source eNB sends Handover Request message including ue-ConfigRelease IE. 2 The target eNB sets FullConfig IE to true if ue-ConfigRelease IE is higher than RRC Protocol release of target eNB. 3 The target eNB sends Handover Request Acknowledge message including FullConfig IE. 4 The source eNB forwards RRC Connection Reconfiguration message to UE. 5 The source eNB transmits RRC Connection Reconfiguration Complete message to Target eNB. 6 The UE deletes current configuration of source eNB and applies new configuration provided by target eNB except security configuration.

SYSTEM OPERATION How to Activate  Select 1 event to use to activate X2 Handover.  ACTIVE_STATE of CHG-EUTRA-A3CNF with PURPOSE A3PurposeIntraLteHandover set to active or ACTIVE_STATE of CHG-EUTRAA5CNF with PURPOSE A5PurposeIntraLteHandover set to active  A3 event is preferred.  Set NO_X2 of CHG-NBR-ENB to false. It is controlled by NBR eNB base.

LTE-SW1005, X2 Handover  Key Parameters CHG-EUTRA-A3CNF/RTRV-EUTRA-A3CNF

LTE-SW1005, X2 Handover  CHG-EUTRA-A5CNF/RTRV-EUTRA-A5CNF

LTE-SW1005, X2 Handover  CHG-NBR-ENB/RTRV-NBR-ENB/CRTE-NBR-ENB/DLT-NBR-ENB

LTE-SV0303, OTDOA

Services

121

LTE-SV0303, OTDOA INTRODUCTION In the Observed Time Difference of Arrival (OTDOA) positioning method, UE makes an observation of the arrival time difference of Reference Signal (RS) from two or more eNBs. Then, the position of UE can be calculated based on the known position of eNBs and the time differences. The time difference between the RS from the serving cell and the neighbor cells are called Reference Signal Time Difference (RSTD). To measure the RS from (probably far away) neighbor cells, a special positioning signal is defined in Release 9 and called Positioning Reference Signal (PRS). PRS was introduced to improve the „hearability‟ of neighboring cells within completing measurements for the downlink OTDOA positioning method. 3GPP recognized that the hearability of the existing cell-specific reference signals was not sufficient to support the OTDOA positioning method. Therefore, hearability can be challenging as a result of neighboring cells being co-channel with the serving cell, especially at locations where the serving cell signal strength is high. In case of E-SMLC, UE provide RSTD information through the LPP protocol layer and eNB provides PRS and base station information through the LPPa protocol layer. Then, ESMLC makes a final decision on the position of UE. The MME transparently relays LPP and LPPa layer information to E-SMLC.

LTE-SV0303, OTDOA BENEFIT  The operator can provide an OTDOA-based location service.  End users can get more accurate location-based services such as maps and navigations.

DEPENDENCY AND LIMITATION Dependency  UE that support OTDOA based on 3GPP Release 9 or later version.  MME to support LPPa protocol  E-SMLC to support OTDOA  eNB that support PRS  Precise synchronization between eNBs is required for better accuracy (GPS synchronization is recommended) Limitation  Air interface throughput is impacted due to PRS broadcasting as there is no PDSCH data in the subframe where PRS located.  In rural areas, there are fewer measureable cells which may impact accuracy.

LTE-SV0303, OTDOA  PRS subframe configuration needs to be manually planned to ensure no overlapping with PBCH, SIBs, Paging, and Measurement Gap scheduling.  No SON Functionality is available to support automatic PRS configuration, PRS configurations will have to be manually planned and configured.

FEATURE DESCRIPTION  The OTDOA positioning method makes use of Reference Signal Time Difference (RSTD) measurements from UE. The RSTD quantifies the subframe timing difference between a reference cell and a neighboring cell. The accuracy of the positioning calculation is improved if UE can provide RSTD measurements from an increased number of cells. RSTD is measured in units of Ts (1/30720 ms) and is reported to the Enhanced Serving Mobile Location Center (E-SMLC) where the location calculation is completed. E-SMLC is a network element within the operator's infra network.  The UE receives an LTE Positioning Protocol (LPP) Provide Assistance Data message from E-SMLC. This message is packaged by MME as a NAS message before being packaged by eNB as an RRC message. The Provide Assistance Data message includes both the reference and neighboring cells information. The reference cell does not have to be the current serving cell for UE.

LTE-SV0303, OTDOA  The PRS are able to coexist with both the cell specific reference signals and the physical layer control information at the start of each subframe (PCFICH, PHICH, and PDCCH). Also, PRS occupies an increased number of resource elements within a subframe relative to the cell specific reference signals to help improve RSTD measurement accuracy. The sequence used to generate the positioning reference signal is a function of the physical cell identity (PCI) and the cyclic prefix duration (normal or extended). The PRS are broadcasted using antenna port 6. They are not mapped onto resource elements allocated to the PBCH, Primary synchronization signal nor secondary synchronization signal. The PRS are only defined for 15 kHz subcarrier spacing. They are not supported for 7.5 kHz subcarrier spacing used by Multimedia Broadcast Multicast Services (MBMS). Below figure shows examples of PRS for normal cyclic prefix. There is a dependency upon the number of antenna ports used for the cell specific reference signal. Additional symbols are used by the cell specific reference signal when broadcast from four antenna ports.  The following figure is Mapping of positioning reference signals (normal cyclic prefix):

LTE-SV0303, OTDOA

LTE-SV0303, OTDOA  The PRS configuration parameters include PRS Bandwidth, PRS Configuration Index, Number of Consecutive Downlink Subframes, and PRS Muting Configuration.  PRS Bandwidth: The bandwidth that PRS occupied. The PRS bandwidth is signalled to UE with a value of 6, 15, 25, 50, 75, or 100 resource blocks. The positioning reference signal bandwidth is always centered on middle of the channel bandwidth. The PRS configuration index is used to define both a periodicity and subframe offset for the timing of the positioning reference signal. The look-up table presented below is used to link the configuration index to the periodicity and subframe offset. Below table is Positioning Reference Signal subframe configuration.  PRS Configuration Index: The PRS Configuration Index (IPRS) defines the periodicity (TPRS) and subframe offset (ΔPRS) for timing of the PRS.  The following table shows the relation among these parameters:

LTE-SV0303, OTDOA  Number of Consecutive Downlink Subframes: The number of consecutive downlink subframes defines the number of subframes during which the positioning reference signal is broadcast within each positioning reference signal period. The number of consecutive downlink subframes can be configured with values of 1, 2, 4, or 6 subframes.  PRS Muting Configuration: PRS muting Configuration consist of 2, 4, 8, or 16 bits map sequence. The periodicity of the muting pattern is defined by the length of the bits map. The PRS positioning occasion will not exist in the subframe if the corresponding bit is set to 0. Based on 3GPP 36.211, PRS is not transmitted in RE allocated to PBCH, PSS, and SSS and UE only uses PRS except resources allocated to PBCH, PSS, and PSS, SSS. PBCH and synchronization signal are transmitted in subframe #0 and bandwidth (6RB), where the corresponding resources are allocated due to this, can transmit PRS to only 38% (FDD) or 50% (TDD) among total REs available for PRS allocation. Therefore, when configuring PRS configuration index in PLD in Samsung‟s systems, it is suggested to operate without transmitting PRS in subframe #0.

LTE-SV0303, OTDOA To allocate PDSCH and PRS to the same RB, it needs to puncture PDSCH in RE to where PRS is transmitted, and this can cause performance decrease of PDSCH reception and PRS reception of neighbor cell. Therefore, Samsung does not transmit PDSCH in RBs where PRS is allocated. In case of Paging and SIB1 transmitted to a fixed subframe, it is assumed that there is no PRS when UE decodes the corresponding traffic and if this is not the case, PRS is received. Therefore, if one of either Paging/SIB1 or PRS needs to puncture the other, the reception performance of Paging/SIB1 or PRS decreases. Thus, it is suggested to service providers to operate without transmitting PRS in subframe (= 5, 9) to where Paging/SIB1 is transmitted, when setting up PRS configuration index. The eNB interworks with E-SMLC with LPPa interface. OTDOA Information Exchange procedure is used to allow the E-SMLC request eNB to transferOTDOA information to the E-SMLC. The procedure consists of the following messages:  OTDOA Information Request/Response/Failure After eNB receives the OTDOA information request message from E-SMLC, the OTDOA information transfer function performs according to reception of the requested information and it performs as follows.

LTE-SV0303, OTDOA o If it received OTDOA cell information: It transmits the OTDOA INFORMATION RESPONSE message including the ODTOA cell information. o If it fails to receive OTDOA cell information: It transmits OTDOA INFORMATION FAILURE message including the cause (value) of the failure. Followings are OTDOA Cell Information:  PCI  Cell ID  TAC  EARFCN  PRS Bandwidth  PRS Configuration Index  CP Length  Number of DL Frames  Number of Antenna Ports  SFN Initialization Time

LTE-SV0303, OTDOA  E-UTRAN Access Point Position  PRS Muting Configuration To implement RSTD measurement, UE need some assistance date send from ESMLC via LTE Positioning Protocol (LPP) interface. The UE receives an LPP Provide Assistance Data message from the E-SMLC. This message is packaged by MME as a NAS message before being packaged by eNB as an RRC message. The Provide Assistance Data message includes information regarding both the reference and neighboring cells. The content of the reference cell information is presented in below table. Similar information is also provided for each of the neighboring cells.

LTE-SV0303, OTDOA After receive the OTDOA assistance data, UE shall start RSTD measurement and report the measurement results to E-SMLC through LPP interface where the location calculation is completed. Measurement Gap Exclusion To ensure UE can perform RSTD measurement, measurement gap shall not be schedule in the subframes where PRS located, otherwise RSTD measurement can fail when UE are doing inter-FA/RAT measurement. The eNB support excluding specified measurement gap offsets and the exact excluded gap offset is configurable (gap pattern 0: 0~39; gap pattern 1: 0~79) to ensure all UE to receive PRS. The excluded offset can be one offset or combination of several offsets. The measurement gap offset exclusion can be enable/disabled (ON/OFF). The operator can configure the starting offset and rang of consecutive gap offset. Starting gap offset range is 0~39 or 0~79 considering of gap pattern, while rang of consecutive gap offset number can be 1~15. For example, if starting offset set to 0 and offset range set to 15, then gap offset 0~14 are excluded.

LTE-SV0303, OTDOA Inter-frequency RSTD Measurement Support In OTDOA positioning method, especially in inter frequency cell deployment, ESMLC may request UE to perform inter frequency RSTD measurement to improve the accuracy by obtaining more RSTD measurement results. This feature enables eNB to configure to start or stop the requested measurement gap sent from UE by a new introduced Release 10 RRC procedure 'Interfrequency RSTD measurement indication', 'Inter-frequency RSTD measurement indication'. After eNB receive the requested measurement gap from UE, eNB may start to configure the gap as UE requested or ignore the gap configuration if the requested gap is not acceptable in the system based on operator's configuration. Currently, three options are provided for operator to control eNB's action when receive UE's 'inter-frequency RSTD measurement indication' message:  Ignore: The eNB ignore UE's request, the measurement gap will not be assigned to UE. The purpose of this option is to limit the impact to current UE's performance as measurement gap may have bad impact to the performance.  Accept: The eNB always accept UE's request. The purpose of this option is to ensure UE to receive inter-frequency RSTD measurement for better accuracy of LCS.

LTE-SV0303, OTDOA  Measurement Gap Algorithms based: In this option, if UE's requested measurement gap offset can be accepted by the current measurement gap allocation algorithms then the gap will be allocated to UE, if UE's requested measurement gap offset cannot be accepted by the current measurement gap allocation algorithms then the requested gap will be ignored. Operator Configurable PRS Power Boosting This feature supports PRS power boosting with respect average max power. To ensure good RSTD measurement performance, PRS power is configured a little bit bigger power. The configurable range is from 0dB to 7.75dB by 0.5 dB step.

SYSTEM OPERATION How to Activate  In case of activate OTDOA function, the OTDOA_ENABLE parameter value must be set to '1(True)' (executing the CHG-POS-CONF command).  In case of activate measurement gap exclusion function, the MEAS_GAP_OFFSET_EXCLUDED parameter value must be set to 'True' (executing the CHG-POS-CONF command).

LTE-SV0303, OTDOA  In case of activate PRS power boost function, the PRS_POWER_BOOST_OFFSET parameter value must be set greater than '0' (executing the CHG-POS-CONF command).  In case of activate Inter-Frequency RSTD measurement gap assignment function, the RSTD_MEAS_GAP_OPTION parameter value must be set to 'AlwaysAccept' or 'ByAlgorithm' (executing the CHG-MSGAP-INF command). Key Parameters RTRV-POS-CONF/CHG-POS-CONF

LTE-SV0303, OTDOA For Inter-Frequency RSTD measurement gap assignment function, RTRV-MSGAP-INF/CHG-MSGAP-INF

For PRS power boost function. RTRV-POS-CONF/CHG-POS-CONF

Counters and KPIs There are no related counters or KPIs.

LTE-SV0503, Multicell and Multicast Coord ination (MCE)

Services

137

LTE-SV0503, Multicell and Multicast Coordination (MCE) INTRODUCTION Multicell and Multicast Coordination Entity (MCE) is an eMBMS entity that controls eMBMS sessions requested by MME. Also, it allocates radio resources in time domain and schedules eMBMS sessions. In addition, it aligns the opening of eMBMS radio channel among cells that belong to the same MBSFN Area. Samsung MCE is provided as an external server. The advantages of centralized MCE architecture are as follows:  SCTP offloading from MME  eMBMS service restoration when eNB restarts or fails  Large MBSFN areas  MCE is an essential entity for eMBMS service. This feature covers following basic and advanced MCE functions:  M2 and M3 interface  eMBMS session start and stop based on MBMS Service Area  1:1 Active and Standby redundancy  eMBMS session restoration when eNB restarts or fails.

LTE-SV0503, Multicell and Multicast Coordination (MCE)  Inter-MCE scheduling coordination  Multiple PLMN supported for RAN sharing  In case of resource allocation and MBMS bearer scheduling, refer to LTE-SV0504 eMBMS Resource Allocation. In addition to MCE, eMBMS related network entities include eNB, MME, MBMS GW, and BMSC in the mobile network.

 BENEFIT    

The operator can provide eMBMS service and increase radio resource utilization. Wide MBSFN area is provided that minimizes eMBMS interference between cells. Continuous eMBMS service is provided even in case when eNB fails and restarts. Resilient MCE system is provided by 1:1 active and standby redundancy

 DEPENDENCY AND LIMITATION Dependency  MME that supports 3GPP Release 11 M3 interfaces  Samsung eNB that supports 3GPP Release 11 M2 interface  Release 9 and later UE that supports eMBMS  MBMS-GW and BMSC are required for eMBMS service

LTE-SV0503, Multicell and Multicast Coordination (MCE) Limitation  256 MBSFN Areas  3000 eNBs and 9000 cells per MCE blade  Simultaneous session processing of 10 per 1 second  256 Sessions per MCE (One Blade) Related Features  LTE-SV0501 eMBMS Basic Function  LTE-SV0504 eMBMS Resource Allocation  LTE-SV0511 eMBMS QoS  LTE-SV0513 eMBMS Service Continuity  LTE-SV0515 eMBMS Session Monitoring

 FEATURE DESCRIPTION M2 Interface Management According to 3GPP TS36.443 V11.3.0, MCE and eNB setup M2 connection and support following procedures.  M2 SETUP procedures to make M2 connection  M2 RESET procedures

LTE-SV0503, Multicell and Multicast Coordination (MCE) 

ENB CONFIGURATION UPDATE procedures to update application level eNB configuration data  MCE CONFIGURATION UPDATE procedures to update application level MCE configuration data  ERROR INDICATION procedures M3 Interface Management According to 3GPP TS36.444 V11.6.0, MCE and MME setup M3 connection and support following procedures.  M3 SETUP procedures to make M3 connection  M3 RESET procedures  MCE CONFIUGRATION UPDATE procedures to update application level MCE configuration data MCE can make multiple M3 connections with different MMEs. MBMS Session Management According to 3GPP TS36.443 V11.3.0 and 3GPP TS36.444 V11.6.0, MCE supports MBMS session control functions.  MBMS SESSION START and STOP procedures initiated by MME  MBMS SESSION UPDATE procedure initiated by MME

LTE-SV0503, Multicell and Multicast Coordination (MCE) 

On receiving M3 MBMS SESSION START message from MME, MCE sends M2 MBMS SESSION START message to eNBs that belong to MBSFN Areas that support the MBMS Service Area ID, which is specified in the M3 MBMS SESSION START message. MCE does not use PLMN ID of TMGI in the message when it decides target eNBs or MBSFN Areas. This means that MBMS SESSION START message can be sent to eNBs even though eNBs does not support PLMN ID of TMGI in the message. If eNB does not support PLMN ID, it should reject the session request. This is to support eMBMS service in RAN sharing network.  The session duration parameter in MBMS SESSION START REQUEST message decides the session duration. When it expires, MCE releases the MBMS Session unless it is updated by MBMS SESSION UPDATE REQUEST message. MCE Redundancy Samsung MCE provides active and standby redundancy. When an active server fails, the standby server takes over the role without any service impact. Following figure shows an example configuration of MCE. Maximum 5 active and standby pairs are equipped in a single chassis (HS23). Active and standby servers share the same IP interface so that the active and standby architecture is transparent to eNB or MME. Active server periodically backups data to standby server. When active server fails (SW or HW fails or board reset), the standby server will take over the role in a few seconds. After switchover, MCE makes SCTP setup with all of the eNBs, and MCE also makes SCTP setup with MME. However, these switchover procedures have no impact on ongoing eMBMS data sessions.

LTE-SV0503, Multicell and Multicast Coordination (MCE)

Inter-MCE Scheduling Coordination When a big city or nation-wide area is covered by multiple MCEs, they need to broadcast synchronized eMBMS data over the entire area. For example, there are two MCEs that cover two disjoint areas respectively. Even though eNBs in two disjoint areas broadcast the same eMBMS service, there could be severe interference in the border area if they are not synchronized. The interference can be removed if eNBs broadcast the same eMBMS data in the same physical location of the frequency at the same time.

LTE-SV0503, Multicell and Multicast Coordination (MCE) In case of inter-MCE scheduling coordination, the MCEs must be configured so that they have the same MBMS Service Area ID with the same physical resource configuration such as RFAP and RFAP offset. In addition, for the MBMS Service Area, they shall receive eMBMS data from the same BMSC. In the figure below, the first two MBSFN areas have the same MBMS Service Area and the same physical resource allocation. The coordinated MBMS Service Area must span over the same frequency and over eNBs that are SFN synchronized. MBSFN Area ID and MBSFN Synchronization Area ID can be different between two MCEs while MBMS Service Area and RFAP and RFAP Offset must be the same. The eNBs in the MBMS Service Areas will be able to transmit synchronized eMBMS data for the same eMBMS session. Each MCE may have its own MBMS Service Area independently of the other MCEs (MBSFN Areas 2 to 256 in the example).

LTE-SV0503, Multicell and Multicast Coordination (MCE)        

   

In case of MBMS Service Area that needs to be synchronized over multiple MCEs, operator shall configure following system parameters the same over the MCEs. MBMS Service Area ID RFAP RFAP Offset MSP MCS Level(Signalling and Data) The number eMBMS subframes per radio frame Configuration of MBSFN Areas that corresponds to the MBMS Service Area. Refer to Information included in MBMS Scheduling Information(3GPP TS36.443 V10.1.0 9.1.7) Information included in MCCH related BCCH Configuration Item (3GPP TS36.443 V10.1.0 9.2.1.13), excluding MBSFN Area ID and Cell Information List. In addition, following requirements must be met. The MCEs shall be connected to the same BMSC. The same MBMS Service Area must be configured over the same frequency, the same PLMN All eNBs in the same MBMS Service must be SFN synchronized. The MBSFN Areas that serve the MBMS Service Area must not support other MBMS Service Areas that cover local regions.

LTE-SV0503, Multicell and Multicast Coordination (MCE)

1 2 3 4

5

Following is overall procedures to apply the coordinated scheduling information to MCEs and eNBs. LSM shall provide coordinated scheduling information to the concerned MCEs Upon receiving the M2 setup request from eNB, the MCE shall provide MCCH configuration information for the cluster MBSFN area Upon receiving the M2 setup response from MCE, eNB shall schedule MCCH by given configurations Upon receiving the M3 session start message for the specific MBMS service area from MME, MCE shall schedule PMCH/MCH by the coordinated scheduling information Upon receiving the M2 MBMS SCHEDULING INFORMATION message for the specific MBSFN area, eNB MAC shall schedule PMCH/MCH by the given information

SYSTEM OPERATION How to Activate The relevant MCE PLD is set as follows:  CHG-MBMSENB-CONF: eNB-MCC/MNC, eNB IP address, and so on, eMBMS status The indexes increases to 3000  CHG-MBSFN-MAPPINGINFO: Set the MBSFN area. (To set the MBSFN area, set the MBMS Service Area Id and the MBMS Synchronisation Area Id.)

LTE-SV0503, Multicell and Multicast Coordination (MCE) Key Parameters CHG-MBMSENB-CONF/RTRV- MBMSENB-CONF

CHG-MBSFN-MAPPINGINFO/RTRV-MBSFN-MAPPINGINFO

LTE-SV0503, Multicell and Multicast Coordination (MCE) Counters and KPIs  MBMS_M2_SETUP: M2 SessionStart, SessionStop  MBMS_SESSION_SETUP: M3 SessionStart, SessionStop

LTE-SV0515, eMBMS Session Monitoring

Services

149

LTE-SV0515, eMBMS Session Monitoring INTRODUCTION Unlike unicast sessions, a MBMS session must be kept very long time period, and there is no feedback from UEs whether they receives MBMS data successfully or not. Therefore, a service monitoring tool is required for operator to monitor whether MBMS data is normally broadcast or not. In this feature, operator can monitor each session based on TMGI. Provided information includes the total number of transmitted and received packets, discarded packets, delayed packets, radio usage rate, and a plurality of configuration information. The operator can check each cell and eNB whether they normally provide eMBMS service or not. Due to hardware resource limitation, LSM provides a limited number of sessions that operator can monitor at the same time.

BENEFIT  The operator can monitor eMBMS session and check the status and quality of eMBMS service.

LTE-SV0515, eMBMS Session Monitoring DEPENDENCY AND LIMITATION Dependency  This feature can be enabled with Samsung eNB, MCE, and LSM. Limitation  The operator can monitor up to 20 sessions at the same time. However, a cell provides the session monitoring information of up to 16 sessions.  The information is updated every 2.56 seconds  Even in case of the same session, the displayed information may be different at a monitoring moment between different cells or between eNB and MBMS-GW/BMSC because of different delays between them. In addition, statistics from RLC and GTP layers cannot be exactly matched at a specific moment because of packets in traversal or different time sources used

FEATURE DESCRIPTION A. eMBMS Session Monitoring This feature checks service quality and normality of the service operation status for each session from BMSC that transmits eMBMS data to eNB that broadcasts eMBMS data via MBMS GW.

LTE-SV0515, eMBMS Session Monitoring The operator can check the information listed on the table below by selecting a specific cell and session (TMGI) through LSM. Also, they can check the information for up to 20 cells or 20 sessions at the same time. The corresponding information is automatically updated in every 2.56 seconds. When a session that meets the condition is created, the information is automatically displayed on the window.  Input: List of ECGI, List of TMGI  Output: Listed below the information table The following information is provided per Cell: TMGI.

LTE-SV0515, eMBMS Session Monitoring

LTE-SV0515, eMBMS Session Monitoring

LTE-SV0515, eMBMS Session Monitoring

LTE-SV0515, eMBMS Session Monitoring

LTE-SV0515, eMBMS Session Monitoring B. eMBMS Session Summary Log If an eMBMS session is terminated normally or abnormally, eNB collects information for the session from each cell and transmits it to LSM. The LSM saves this information for a certain period of time and discard it automatically. If traffic volume is too large between eNB and LSM, the operator can remove the normal termination cases. eMBMS Session Summary Log information includes all the counting information for eMBMS Session Monitoring on the above tables and the following information is collected additionally. eMBMS session can last up to 19 days according to its standard. However, eNB closes the Session Summary Log periodically and reports it to LSM.

C. eMBMS Service Status Report The operator can identify the current eMBMS service area through LSM.

LTE-SV0515, eMBMS Session Monitoring The operator can check MBSFN area list that supports each MBMS service area and they can retrieve the following information of each MBSFN area. Input: MCE, MBSFN Area ID Output: Refer to the following table The following information is provided per MBSFN area.

LTE-SV0515, eMBMS Session Monitoring SYSTEM OPERATION How to Activate  Execute the RTRV-SSL-CTRL command to retrieve the existing configuration settings for Session Summary Log (SSL).  Execute the CHG-SSL-CTRL command to configure the settings for Session Summary Log (SSL).  Execute the RTRV-MCERSC-STS command to retrieve the resource status of Multi-cell/multicast Coordination Entity (MCE). Key Parameters CHG-SSL-CTRL/RTRV-SSL-CTRL

RTRV-MCERSC-STS

LTE-SV0515, eMBMS Session Monitoring

REFERENCE N/A

LTE-SV0517, eMBMS Service Restoration

Services

161

LTE-SV0517, eMBMS Service Restoration INTRODUCTION eMBMS service restoration is to recover eMBMS sessions when eNB or MCE or MME fails. When MME fails, eMBMS session context will move to another MME. The MCE shall be able to re-associate the existing eMBMS sessions with the new MME that requests MBMS Session Start Request message with 'Re-establishment Indication' flag. When MCE restarts, it will perform M3 Setup and send M3 Reset message to MME. The MME will send original eMBMS Session Start message to recover the sessions. In case of M3 link failure, MCE deletes all the related eMBMS sessions and tries to make M3 Setup repeatedly. Once the M3 setup is completed, MCE will send M3 Reset message to MME. MCE can be connected to multiple MMEs (up to 16). However, MCE expects that the same MME controls the same MBMS sessions, which means that the MCE rejects any duplicate MBMS Session Start Request message from other MME without 'Reestablishment Indication' flag.

BENEFIT  This feature enables MBMS service to continue even in case of MME failure, or MCE failure, or M3 path failure.

LTE-SV0517, eMBMS Service Restoration DEPENDENCY AND LIMITATION Dependency  MME that support 3GPP Rel-12 Limitation  Max 16 MMEs supported

FEATURE DESCRIPTION eMBMS Service Restoration When eNB Fails The MCE shall not delete MBMS session information in the event of STCP keep alive message failure. When eNB reboots, MCE transmits all the MBMS session information as soon as eNB and MCE setup M2 connection. Sine eNBs in the same MBSFN area including the rebooted eNB use the synchronized SFN and the same timestamp offset value for each MBMS session, the rebooted eNB can keep the restored MBMS sessions synchronized with neighbor eNBs. The following figure shows eNB failure case of the centralized MCE:

LTE-SV0517, eMBMS Service Restoration

From eNB's respect, it shall be treated as normal M2 setup, since it cannot differentiate from normal start to recovered session. MCE shall not flag any non-standard information to eNB.

LTE-SV0517, eMBMS Service Restoration

MME Restoration Support The MME requests eMBMS Session Start Request message, and eMBMS session is associated with MME. In case of MME failure, another MME can send eMBMS Session Start Request message with 'Session Re-establishment Indication' flag when the primary MME fails. Then, MCE will re-associate eMBMS Session to the secondary MME that requests session re-establishment

LTE-SV0517, eMBMS Service Restoration

The MBMS Session Start Request message with 'Re-establishment indication' flag may differ from the existing one. In this case, MCE shall send MBMS Session Update message to all eNBs of the corresponding MBMS Service Area. MCE Restoration When MCE restarts or it detects a failure in M3 link, it will make M3 setup and sends M3 Reset message to MME. Then, MME will send MBMS Session Start message to MCE. In case of M3 link failure, MCE will release all eMBMS sessions that it has managed.

LTE-SV0517, eMBMS Service Restoration SYSTEM OPERATION How to Activate  This feature is basically enabled and operator cannot disable.  Dependency with other feature, limitation and prerequisite: RTRV-MCECONNPARA/CHG-MCECONN-PARA :: MME_FAILOVER_TIMER. Key Parameters There are no related parameters. Counters and KPIs eMBMS MCE session-related statistics have the following items (The operator can retrieve them by MME index.) Node restoration-related parts cannot be checked but operator can observe that the MBMS_SESSION_SETUP statistics of the other MME index are increasing. MBMS_SESSION_SETUP: SessionStartAtt, SessionStartSucc, and so on.

LTE-SO0201, Intra-LTE ANR

SON

168

Contents Introduction to ANR Framework of ANR Benefits of ANR Types of ANR Call Flow/Design of ANR Use Cases in ANR

Introduction to ANR Samsung automatic neighbor relation (ANR) automatically configures and manages the intra-LTE neighbor relation table (NRT), and it aims to maintain the optimal NRT reflecting changes in the communication environment during the system operation. Stable UE mobility of Samsung LTE cells is guaranteed by optimized NRT management.

According to 3GPP specifications, the purpose of the Automatic Neighbor Relation (ANR) functionality is to relieve the operator from the burden of manually managing Neighbor Relations (NRs). This feature would reduce the operators effort to provision. Samsung ANR provides the following functions depending on the SON phase. 1. 2.

Self-configuration phase (Initial NRT based on the location of Neighbor) Self-optimization phase (Dynamic NRT Update either by UE or LSM)

ANR Framework

Benefits of ANR Manually provisioning and managing neighbor cells in traditional mobile network is challenging task and it becomes more difficult as new mobile technologies are being rolled out while 2G/3G cells already exist. For LTE, task becomes challenging for operators, as in addition of defining intra LTE neighbor relations for eNBs operator has to provision neighboring 2G, 3G, CDMA2000 cells as well.

The system performance indicators such as HO success rate and call drop rate are optimized by configuring NRT optimized for coverage and air status of each LTE cell. This guarantees reliable mobility of UEs in the RRC_IDLE mode and the RRC_CONNECTED mode.

Types of ANR Manually adding neighbor cells in network is indeed a very hectic process and prone to errors as well. While networks are becoming more and more complex, it is required to find an automatic and a more optimized way of adding neighbor cells. ANR comes under the umbrella of Self Organizing Networks ( SON) features. ANR relies on UE to detect unknown cells and report them to eNB. There are two major types:

i) UE based ANR ii) LSM Based ANR

UE Based ANR

EMS

MME

e new

NB

eNB (Serving Cell)

n isitio u q c IP a

X2 Interface Setup Me

UE

EC GI a

cq uis ur em tio (N n e n ew tR PC ep or I) t

as

Re

UE

a

I CG E d

New eNB (Target Cell)

LSM Based ANR EMS

ECGI/IP Acquistion

eNB (Serving Cell)

X2 Interface Setup

Me

as

ure ( N men ew t PC Rep ort I) UE

UE

New eNB (Target Cell)

Design of ANR Samsung ANR provides the following functions depending on the SON phase

1. 2. 3.

Initial NRT auto-configuration Addition of NBR cells in NRT based on UE or LSM Automatic NRT management (NBR rank, deletion based on stats etc.)

Dependency: 1. UE ECGI acquiring function support: For UE-based NR addition, UE should support the E-UTRAN cell global identifier (ECGI) acquiring function. 2. LSM-based NR addition function support: The operator should set LSM-based NR addition flag to True.

NBR addition based on UE reporting

ECCB UE detects unknown cell

UE reads ECGI

UE reports unknown cell/PCI report ENB requests ECGI

OAM

PCI report OAM requests ECGI

UE reports ECGI ECCB reports ECGI ENB IP request/ Tunnel IP req

ueBasedCgiAvail ability flag is on so OAM request ECGI

Tunnel IP req to MME Tunnel IP resp to ENB

Tunnel IP report

Update NRTs

X2 setup ENB NRT

Cell NRT

NBR addition based on UE reporting

ECCB UE detects unknown cell

UE reports unknown cell/PCI report

OAM

PCI report ueBasedCgiAvail ability flag is OFF an d LSM based ANR is OFF

No action

NBR addition based on LSM

ECCB UE detects unknown cell

UE reports unknown cell/PCI report

LS M

OAM

PCI report ueBasedCgiAvail ability flag is OFF an d LSM based ANR is ON.

New PCI report to noti

ENB and cells info

Update NRTs

X2 setup

ENB NRT

Cell NRT

NBR addition based on UE reporting

ECCB UE detects unknown cell

UE reports unknown cell/PCI report

OAM

PCI report

OAM requests ECGI

ueBasedCgiAvail ability flag is ON

ECGI report

ENB IP request/ Tunnel IP req

OAM found reported ENB in ECGI report exist in ENB NRT then OAM waits for 2 secs for Tunnel IP res, after that, time out and no action

No action

LTE-SO0301, PCI AutoConfiguration

SON

182

Contents PCI Introduction PCI Conflict types Samsung PCI management PCI Auto configuration PCI conflict Detection PCI conflict Resolution (PCI Auto re-configuration) PCI Management Settings and flags SON Logs Collection

PCI Introduction PCI: Physical Cell ID is an identification of a cell at physical layer. It is similar to Primary Scrambling Code of UMTS cell. In order for the UEs to identify the source signal each eNBs(Cells) is assigned PCI. There are 504 unique PCI limited values available. Hence eNBs(Cells) have to reuse PCI in network. PCI is determined by PSS and SSS, two synchronization signals as below: 1.Primary Synchronization Signal, cell id(0-2) 2.Secondary Synchronization Signal, cell id group(0-167) PCIi = 3 x j + k where: i = 0 … 503 j = 0 … 167group k = 0 … 2 ID PCI conflicts occur when neighbor eNBs(Cells) have same PCI. There are two types of PCI conflict: 1) PCI Collision 2) PCI Confusion

PCI CONFLICT TYPEs

PCI Collision  PCI collision occur when a cell (say cell of ENB1) has neighbor cell relationship with a cell (say cell of ENB2) having same PCI and frequency (EARFCN DL). Below picture depicts the same. ENB1 PCI = 100 EARFCN DL =3880 ENB2 PCI = 100 EARFCN DL =3880

PCI Collision ENB1 detects PCI CONFLICT (PCI collision) with ENB2.

PCI Confusion  PCI confusion noticed when a cell(say cell of ENB1) has neighbor cell relationship with two cells (say a cell of ENB2 and a cell of ENB3) for mobility purpose and both cells have the same PCI and frequency (DL EARFCN). Below picture depict the same scenario.

ENB3 PCI = 100 EARFCN DL=3880

ENB1 PCI = 200

ENB2 PCI = 100 EARFCN DL =3880

PCI Confusion ENB1 detects PCI CONFLICT (PCI confusion) between ENB2 and ENB3.

Samsung PCI Mgmt Blocks PCI Management functionalities are distributed in SAMSUNG eNB. 1) JOB1 : Initial PCI allocation is done by LSM. 2) JOB2 : PCI conflict detection and reporting of PCI conflict are done by eNBOAM 3) JOB3 : PCI conflict resolution(PCI re-allocation) is done by LSM

SAMSUNG eNB OAM OSAB OAM

JOB1 : JOB2 : JOB3 :

LSM SONA

PCI Optimization  Design Policy for PCI optimization o PCI should satisfy the collision-free and confusion-free condition. o PCI should be selected such that inter-CRS (Cellspecific Reference Signal) interference is reduced. o In case of a PCI conflict, the cell which detects the conflict sends a conflict noti (notification) to its LSM with the information of the two cells in conflict. o To resolve the conflict, LSM changes the PCI of one of the cells (The one with higher ECGI). o In case the two conflicting cells belong to different LSMs and the higher ECGI cell does not belong to LSM in which conflict was reported; the LSM will change the PCI of the lower ECGI cell. © SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

Initial PCI and PCI Re-Configuration  Initial PCI auto-configuration  PCI Re-configuration

EMS - Initial PCI Allocation - PCI Reconfiguration

PC I

eNB

. PCI conflict report . 2 tier PCI List

- PCI Conflict Detection - Collect PCIs used inner 2 tier NBR

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

Neighbor eNB X2

Initial PCI allocation  Allocation Strategy: Neighboring sites are grouped into clusters, and each cluster is assigned a limited number of Code Groups(i.e PSS). Each site is assigned a specific Code Group and each sector a specific Color Group(i.e SSS).

PSS ID =0

PSS ID =2 γ cell

α cell

PSS ID =0 PSS ID =2

β cell

PSS ID =1

γ cell

α cell

β cell

PSS ID =1

In 2/4 CRS mode, there are 3 patterns for CRS position

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

Initial PCI auto configuration  LSM assists in distance-based initial PCI selection o The distance (D) for PCI conflict region is calculated as following D = max (R * R_Multi, LimitDist)  R: Inter-site distance  R_multi = [0, 4]  LimitDist = [0, 100] km

o Operator can change the distance parameter value in LSM SON GUI. o If all PCIs are used in the region, D, then LSM selects a PCI maximizing minimum reuse distance LS M

D

R

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

PCI conflict region

PCI conflict detection

PCI conflict detection eNB checks PCI Collision or PCI Confusion and reports to LSM when on one of the following event occurs:

1. New NBR is added 2. On receiving X2 setup request/response and eNB configuration update

PCI conflict detection : New NBR addition ENB executes PCI conflict algorithm when new NBR is added in NRT

ENB NRT Cell No

Index

ENB ID

TCI

PCI

0

0

308

16

200

3880

0

1

504

17

300

3880

0

2

Addition of new NBR at index 2

EARCN DL

Trigger point for PCI conflict algorithm ENB executes PCI conflict algorithm when ENB receives X2 set up request/response or eNB configuration update

Cell No 0

TCI

ENB ID 304

16

PCI

EARFC N DL

Cell No

201

3880

0

TCI ENB ID 304

X2 setup request/eNB configuration update

eNB1

16

PCI

EARFC N DL

201

3880

eNB2

X2 setup response

eNB1 NRT Cell No 0

eNB2 NRT

TCI Ind ex 0

ENB ID 308

PCI 16

200

EARC N DL 3880

Cell No0

Index

ENB ID

TCI

PCI

EARC N DL

0

0

304

16

201

3880

0

1

504

17

300

3880

PCI conflict Resolution

PCI Reconfiguration  PCI optimization consists of two steps: o PCI conflict detection : eNB reports PCI conflict to LSM. o If PCI conflict report is received , LSM re-allocates the new PCI

4. Select new PCI

LSM

2. Check PCI conflict

eNB1

1. X2 : Setup Req/Rsp 2. eNB conf. update

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

eNB2

2 Tier Nbr PCI reconfiguration  Re-allocated PCI is not used in 2 tier neighbor cells o o o o

2 Tier Neighbor Cell information is exchanged via X2 configuration Update eNB monitors which PCI is being used by neighbor cells and neighbor's neighbor cells. When eNB detects PCI conflict, eNB reports PCI conflict to LSM. LSM re-allocates the new PCI which is not included in the 2 tier PCI list and maximizes the minimum reuse distance 4. Select new PCI

LSM

2. Check PCI conflict

Neighbor eNB

eNB 1. X2 : eNB conf. update (served and neighbor cell PCI)

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

Nbr-to-Nbr eNB X2 : eNB conf. update

PCI conflict Resolution eNB1 PCI = 100 EARFCN DL 3880 Cell ID : 4000

eNB2 PCI = 100 EARFCN DL 3880 CELLID 3000

LSM

eNB1 detects PCI conflict PCI conflict report : eNB1,CELLID : 4000 eNB2,cellID:3000,PCI=100,EARFCN DL 3880,..

eNB2 starts PCI change timer

eNB1 and eNB2 grown in LSM LSM decides to change PCI of eNB1 as having larger cell id : 4000 LSM sends PCI change timer message to eNB2 LSM fetch 2-timer PCI list of eNB1

eNB1 changes PCI to 200

LSM allocates new PCI=200 to eNB2

Notify change in PCI via eNB config update eNB2 stops PCI change timer

PCI Management Settings and flags

PCI auto configuration: Property setting1  PCI related parameters in SON Property window Name

PCI Type

Range

distance/ average/minimum

PCI Multiple

1~4

PCI Limit Distance

1 ~ 100

Description Criteria of the effective radius when allocating PCI. Can set to minimum, average or distance. - minimum: using R as distance with nearest neighbor cell. - distance: criteria of fixed distance. - average: using R as average distance with cell inside initDistance.

Expansion range of calculating the effective distance when allocating PCI. Minimum of the effective radius when allocating PCI. Set PCI Black List.

PCI Black List

0 ~ 503

PCI Reconfig Mode

cellAdminLock/ cellAdminShutdown

PCI Reconfig Timeout

1 ~ 100

PCI Reconfig Method

NRTBased /LocatedBased

Mode of PCI Reconfiguration. (eNB change Administrative Status in case of PCI Reconfiguration) Timeout of PCI Reconfig Mode.

Select a PCI reallocation Algorithm.

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

PCI auto configuration: Property setting2  PCI auto configuration setting in LSM  PCI auto-configuration is activated in the cell grow procedure  PCI auto-configuration activation procedure in LSM  Input latitude and longitude for eNB location information  select the checkbox and apply

© SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

PLD parameter setting: PCI auto conf  Configurable PLD parameter Parameter PCID_ENABLE

Range 0~2

Description Controls SON PCID operation at 3 stages. -0=sonFuncOff: Performs X2 monitoring. -1=sonManualApply: After initial PCI auto configuration, X2 monitoring and PCI collision/confusion detection are performed, the PCID in which collision/confusion was detected can be reallocated manually. - 2=sonAutoApply: After initial PCI auto configuration, X2 monitoring and PCI collision/confusion detection are performed, the PCID in which collision/confusion was detected is reallocated automatically by the LSM SON manager.

PCID_ENABLE (RTRV-SONFN-ENB) : This flag tells PCI conflict detection mode OFF Mode : 2tier PCI list management through X2 monitoring is only performed .

Manual Mode : 2tier PCI list management through X2 monitoring and PCI collision/confusion detection is automatically performed. For the PCI reallocation function, PCI for a cell is reallocated with operator approval. Auto Mode : 2tier PCI list management through X2 monitoring and PCI collision/confusion detection, PCI reallocation functions are performed automatically. © SAMSUNG Electronics Co., Ltd. Confidential and Proprietary

SON Logs collection

ENB- SON logs Log Name/Command osab.log 1 & osab .log2 RTRV-SONFN-ENB

Log Path

Remarks

/var/log

Contains ENB-OAM SON information Contains SON related ENB level NOTE : PCIID_ENABLE_ENHANCED parameter tells PCI detection mode.

Contains serving cells(/s) info of ENB RTRV-CELL-IDLE RTRV-NBR-ENB

Contains neighbor eNB info of eNB.

RTRV-NBR-EUTRAN

Contains E-UTRAN neighbor cell info of serving cell(/s) of eNB.

Note : Collect above info for debugging PCI Conflict issue.

LSMR –SON logs Log Name

Log Path

Remarks

Event History

LSM GUI

On LSM GUI dashboard you can check current alarm.

Notification logs

/log/msg/noti/noti..log

At this path you will find hourly log file for almost 30 days, also logs file will not be created for duration when eNb does not send any notification, which is rare in field.

Response logs

/log/msg/resp/resp..log

At this path you will find hourly log file for almost 30 days, also logs file will not be created for duration when eNb does not send any notification, which is rare in field.

Operation History LSM GUI

On LSM GUI dashboard you can check operation history.

/log/app/mf.son.log

Contains LSM SON Module info

SON Log Management

LSM GUI

Contains PCI management related triggered event info

SON Property

LSM GUI

Contains PCI auto configuration/re-configuration related info.

SON app log

Note : Collect above info for debugging PCI Conflict issue.

LTE-SO0401, RACH Optimization

SON

208

RACH Optimization BENEFIT  The operator can reduce previously spent CAPEX and OPEX cost for configuring and managing the RSI and PRACH parameters of LTE cells.  Minimize UE access delay and maximize UL capacity

DEPENDENCY AND LIMITATION Dependency Self Configuration O Application of the RSI configuration requires location information of the cell where the RSI allocation is required. Self Optimization O Application of the RACH optimization needs 3GPP Rel.9 UE support including RACHreport in UE information message.

Limitation Self Configuration O The location based RSI allocation method might cause a RSI collision with a cell that does not use the same EMS. Self Optimization O RSI allocation method might cause RSI reallocation failure when X2 connection is unable between eNBs.

RSI autoconfiguration

RSI auto configuration involves the following operation: 1 When installing a cell, EMS receives the latitude and longitude coordinates of the installed cell through the operator or GPS. 2 The operator inputs the parameters related to RO of SON Property window of EMS.

RSI autoconfiguration 3 The distances to the currently operating cells that use the same FA among the cells within the already input NRT distance threshold are calculated, and in order of proximity, the NMax_virtual_NRT numbers of cells are selected to configure the virtual NRT. 4 Used Root Sequence set is configured by collecting root sequences that are used by cells in Virtual NRT. 5 An available RS set is configured in the whole RS pool by excluding the used root sequence set. 6 RSI is allocated by selecting an allocable RS range among the available RS set. At this point, if there is no RS range among the available RS set that satisfies the consecutive RS, eNB includes RS range which is used in the farthest cell into the available RS set, and allocates RSI by selecting an allocable RS range among the available RS set. The eNB repeats step 6) until an RSI can be allocated to the growing cell.

RSI collision RS collision refers to a situation where two cells in neighbor relation use the same FA and RS. In this case, as UE of the two cells selects one preamble in an overlapping RS range and then transmits the PRACH preamble to attempt the initial connection to the network, the probability of contention increases. The RS collision detection function is performed for the following cases:  For the case of two cells with Inter-eNB neighbor relation: The function operates when cell configuration change message is received through X2 interface.  For the case of Intra-eNB neighbor cell: The function operates when eNB Configuration update of itself is performed.

RSI reallocation When RSI conflict is detected then RSI is reallocated on the cell which has bigger ECGI.

Dedicated vs. Contention Preamble Adjustment An optimal number of dedicated preambles dictate new subscriber accessibility and HO latency. Using HO statistics, RO control function controls the number of dedicated preamble dynamically. For example - in a lightly loaded cell with low mobility activity, RO control function will split the available preambles to allow for more contention preambles. In a cell with lot of mobility activity and near-capacity user count, RO control function will split the available preambles to have more dedicated preambles. The following figure shows the general flow of contention vs. dedicated preamble split:

Adjustment of PRACH Configuration Index and Power related parameters Y

Avg_Pre_Sent_Num > Th2_Up

Y

Y

Det_cont_Ratio > Th3_up

(BI_OPT_ENABLE == 1) && (Max Opportunity Reached

N N

Avg_Pre_Sent_Num < Th2_Dn && Det_Cont_Ratio < Th3_Dn

Y

N

Y

Backoff Indicator ==0 Increase Oppurtunity N

N

NO Action

Reset BackOff Indicator to 0

Decrease Power & Oppurtunity

NO Action

Increase Backoff Indicator

PRACH Configuration Index

Backoff Indicator Index

Backoff Parameter value (ms)

0

0

1

10

2

20

3

30

4

40

5

60

6

80

7

120

8

160

9

240

10

320

11

480

12

960

13

Reserved

14

Reserved

15

Reserved

Architecture Samsung RACH optimization operates in eNB's SON agent and EMS's SON manager. The overall structure is as follows: EMS SON Manager: RSI Management Function  Create initial RSI  Performs a RSI reallocation upon receiving the RSI collision/confusion notify information message.  RSI reallocation cell selection  Transmits a new RSI to the eNB of the cell whose RSI has been changed. eNB: SON Agent  RO Statistic Management O It periodically collects and accumulates the RO-related statistics information from UE and eNB. O It receives changed RO-related parameters and transmits to the Radio Resource Control (RRC) block.

Architecture RO Parameter Control Function O It changes RO parameters at every RACH parameter decision interval based on accumulated RACH statistics.

RSI Collision Detection Function O It detects RSI collision through the ENB_CONFIGURATION_UPDATE message received from the call processor.

Mobility Load Balancing

Contents Active Based Load Balancing Idle Based Load Balancing

Active Load Balancing

Active Load Balancing Samsung intra-LTE MLB (Mobility Load Balancing) supports ‘load balancing between carriers’ (=inter-frequency MLB), ‘load balancing between sectors’ (= intrafrequency MLB), ‘load balancing between multi-operator frequencies’. The load balancing between carriers resolves the overload state of the cell or maintains the difference of cell loads between the co-located inter-frequency cells within the range configured by an operator. This is achieved through inter-frequency HO based on the cell loads in a multi-carrier LTE network. (The load balancing between multi-operator frequencies is supported by properly setting carrier groups.) The load balancing between sectors resolves the overload state of the cell through intra-frequency HO based on cell loads.

Load Monitoring Source Cell Monitoring The load of source cell is monitored periodically and if load is above threshold then MLB is triggered. Neighbor cell Monitoring The high rank Nbrs in each carrier is periodically monitored by using X2 Resource Status Reporting. X2 Resource Status Request shall include below information. Report Characteristic IE: - Composite Available Capacity Group IE is used. Reporting Periodicity IE: - Reporting Periodicity is filled. *Load Monitoring and triggering of MLB is done by CSAB

Measurement Configuration Measurement configuration is done on the selected candidate UEs for the period (T_MEASUREMENT_COLLECTION_LB) for collecting measurement reports. Event A3 – Intra-frequency measurement Event A4 – Inter-frequency measurement

MLB on Carrier Group Load equalization within intra-group carriers Offloading to intra-group carriers Offloading to inter-group carriers

Load Based HO Collect measurement report in duration (T_MEASUREMENT_COLLECTION_LB) for the candidate UE and create (target UE, target cell) Pair. Initiate handover for all the target UE to the target cell with cause IE- ‘Reduce Load in serving cell’. * Handover is done by ECCB block

Idle based Load Balancing

Idle based

Load Balance the idle Ues. Being in IDLE state, the UEs do not communicate with the Base Station and therefore the Base Station has no knowledge of their presence. The only way to control camping on the cell is to modify cell reselection priorities, offsets and threshold through SIB 3,5 and RRC Connection Release.

Measurement Configuration

The dedicated cell reselection priority information is included in the IdleModeMobilityControlInfo IE of the RRC Connection Release message. After the timer expires, an idle mode UE shall use the cell reselection priority information in the received SIB3 & SIB5. (The cell reselection priority of a serving carrier is contained in the SIB3 and those of inter-carriers are contained in SIB5.)

UE Search Rate

eNB tries to distribute CA capable UEs and non-CA UEs so that the percentage of actually total RRC released UEs for each carrier approaches the percentage calculated from the UE search rates

Idle Mode LB Configuration

RTRV-EUTRA-FA;

CELL_NUM FA_INDEX DUPLEX_TYPE STATUS EARFCN_UL EARFCN_DL PRIORITY Q_RX_LEV_MIN 0 0

0 1

TDD FDD

EQUIP EQUIP

38800 19356

38800 1356

RTRV-TM-CNTR CELL_NUM LOAD_EQUALIZATION_ENABLE IDLE_MODE_LB_ENABLE 0 ON Auto 1 ON Manual RTRV-IDLE-LB NUM_OF_NR_FOR_IDLE_LB 16

IDLE_LB_ENTER_THRESHOLD[%] 20.0

5 7

-64 -64

IDLE_CA_USE OFF OFF

PERIOD_FOR_IDLE_LB[min] 5

MRO (Mobility Robust Optimization)

Contents Too Early HO Too Late HO HO to wrong cell Coverage Hole

MRO MRO is triggered at regular intervals, and controls HO parameters based on the below HO statistics collected during the interval. Too Early HO Too Late HO HO to Wrong Cell Samsung MRO controls CIO, the HO parameter that changes HO time at the cell’s level, in order to satisfy KPI on HO success rate and to reduce ping-pong HO; if KPI is not satisfied, the function controls the CIO value based on the tendency of the HO-related problems. It also monitors if the HO or call drop rate performance sharply slows down for a certain period of time after changing the CIO value. If so, it performs fallback action to return to the previous CIO value, maintaining stability of HO performance.

Too Early HO Too Early HO due to HO FAIL 1. 2. 3. 4.

UE transmits the MR message initiated by triggering HO. UE receives the HO Command message from the serving cell. UE fails HO with the target cell. UE requests for RRC Connection Reestablishment to the serving cell.

Too Early HO due to RLF After HO 1. 2. 3. 4. 5. 6. 7.

UE transmits the MR message initiated by triggering HO. UE receives the HO Command message from the serving cell. UE successfully performs the HO with the target cell. UE creates RLF in a short period of time (Tstore_ue_cntxt). UE requests for RRC Connection Reestablishment to the current serving cell. The serving cell transmits the RLF INDICATION message to the target cell through the X2 interface. The target cell transmits the HANDOVER REPORT message to the serving cell through the X2 interface.

Too Late HO Too Late HO RLF before Triggering 1. 2. 3.

RLF occurs without any HO initiation in UE. UE requests for RRC Connection Reestablishment to the other cell. Cell transmits the RLF INDICATION message to the serving cell through the X2 interface.

Too Late HO RLF After Triggering 1. 2. 3. 4.

5.

UE transmits the MR message initiated by triggering HO. UE fails to receive a HO Command message from the service cell, or fails to perform HO with the target cell after receiving a HO command message. UE requests for RRC Connection Reestablishment to the target cell. UE informs retention of RLF report information in the reestablishment with the target cell. (If UE retains the RLF report information, this information is provided through the UE Information procedure.) The target cell transmits the RLF INDICATION message to the serving cell through the X2 interface. (This message contains the RLF report information if it is acquired.)

HO to wrong cell HO to wrong cell RLF after Triggering 1. 2.

3. 4.

UE transmits the MR message initiated by triggering HO. UE fails to receive a HO Command message from the service cell, or fails to perform HO with the target cell after receiving a HO Command message. UE requests for RRC Connection Reestablishment to the other cell, not to the serving cell or the target cell. The third cell transmits the RLF Indication message to the serving cell through the X2 interface.

HO to Wrong cell RLF after HO 1. 2. 3. 4. 5. 6. 7.

UE transmits the MR message initiated by triggering HO. UE receives the HO Command message from the serving cell. UE successfully performs the HO with the target cell. UE creates RLF in a short period of time (Tstore_ue_cntxt). UE requests for RRC Connection Reestablishment to the other cell, not to the serving cell or the target cell. The other cell transmits the RLF INDICATION message to the target cell through the X2 interface. The target cell transmits the HANDOVER REPORT message to the serving cell through the X2 interface.

Coverage Hole Coverage Hole is an area where SNR of both serving and allowed neighbor is below the level needed to maintain basic service.

Coverage Hole Coverage Hole is present if the following condition satisfyRSRP {BestNeighborCell} – RSRP{ServingCell} < 0 RSRP of the cells is retrieved from RLF report information from UE which was collected by UE before RLF

On the basis of coverage hole, the transmission of RRH is determined

Control of Handover Parameter

Control of Handover Parameter Handover is triggered when event A3 is sent from UE when following condition is met – HOMargin = RSRP(target) – { RSRP(serving) + a3offset + hysteresis – CIO(cellindividualoffsetEutran)} • To reduce Too early HO Triggering, MRO increase HO margin by decreasing the CIO by 1 step. • To reduce Too Late Handover, MRO decrease HO margin by increasing CIO by 1 step. • If HO success rate by neighbor cell ≥ HANDOVER_SUCCESS_KPI, the Samsung MRO function raises HO margin by adjusting the CIO value in order to decrease ping-pong HO. If the HO or call drop rate performance is deteriorated after a certain period of time after the changed CIO is applied, the function performs fallback action to return to the previous CIO value for maintaining stability of HO performance.

LTE-OM9004, CSL (Call Summary Log) Rep ort

System Test and Analysis

244

LTE-OM9004, CSL (Call Summary Log) Report INTRODUCTION This feature collects the detail information for a call. The call release type, call duration, and handover information and so on are automatically collected and transmitted to EMS or external server.

BENEFIT 

The operator can analyze the detail information of a call.

DEPENDENCY AND LIMITATION Dependency  External server for CSL data is required. . Limitation  To support for all calls including normal calls, it is required to explain in advance about expending LSM capacity or external server. (Basically, LSM can store only the CSL data of abnormal calls.)

LTE-OM9004, CSL (Call Summary Log) Report FEATURE DESCRIPTION The CSL data is collected by eNB. When a call is setup, eNB starts to collect information for the call. If the call is released, eNB reports CSL data to the external server.

By the configuration, eNB can support following cases:  Case1: LSM- CSL data of abnormal calls  Case2: LSM- CSL data of all calls  Case3: LSM- CSL data of abnormal calls, External server - CSL data of all calls  Case4: LSM- CSL data of all calls, External server - CSL data of all calls

LTE-OM9004, CSL (Call Summary Log) Report The CSL data includes detail information for a call. It includes a total of 10 information items: call information, common item information, connection information, release information, handover information, throughput information, RF information, adjacency information, UE history information, and call debugging information.

 SYSTEM OPERATION How to Activate The operator can control to report the collected CSL information to external server by executing the CHG-CSL-INFO COMMAND. Key Parameters RTRV-CSL-INF/CHG-CSL-INF

Counters and KPIs There are no a related counters or KPIs.

LTE-OM9010, VoLTE Monitoring

System Test and Analysis

248

VoMA  INTRODUCTION The operator commands into Element Management System (EMS) to trigger the trace of VoLTE calls (UEs or cells) at eNBs. The eNB, after receiving the commands from EMS, collects the information of VoLTE traffic and sends them to EMS (or the external server). The operator can analyze the quality of VoLTE service and identify the cause and the location of problems traffic by post-processing the collected information.

 BENEFIT   

The operator can get benefits in analyzing the quality of VoLTE service and identifying the cause and location of problems. VoLTE quality monitoring: Loss, jitter, and delay Identification of problem causes: Decompression failure due to RoHC error, loss, duplicated packet, out-of-order, and delay Isolation of the section that problems occur: UL air, backhaul + core network, inter eNB, and DL air section.)

VoMA  DEPENDENCY AND LIMITATION Dependency  The LTE device  The EMS is required.  The Mobility Management Entity (MME) is required to get TraceReference for UE trace scenario.  The Global Positioning System (GPS) is required to analyze the delay of VoLTE packets.

Limitation  eNB logging capacity is 10 calls/eNB or 6 calls/cell

VoMA  FEATURE DESCRIPTION Basic concept The operator commands into EMS (Element Management System) to trigger the collection of the information of VoLTE traffic (for some UEs or cells) at eNBs. The eNB, received the commands from EMS, collects the information of VoLTE traffic as indicated and sends them to the EMS or external server. The operator can monitor and analyze the quality of VoLTE traffic by post-processing the collected data. The following figure shows VoLTE monitoring:

VoMA Operation Scenario

UE Trace The operator can select several VoLTE UEs to be monitored by using TraceReference. Therefore, end-to-end VoLTE quality from originating UE to terminating UE can be monitored. Before enable VoLTE monitoring tool, operator should know TraceReference of a specific VoLTE UE to be monitored. (for example, from signal trace)

Cell trace The operator can select cells, which are to be monitored by using specific cell ID. Then random VoLTE UEs in a certain cell are monitored. Therefore, VoLTE quality of a certain cell can be monitored. The following figure shows flow chart and collected information:

VoMA

VoMA Analyzing Results (Example) By post-processing the collected information, operator can analyze the quality of VoLTE service (such as loss, jitter, and delay) and identifying the cause (such as decompression failure due to RoHC error, loss, duplicated packet, out-of-order, and delay) and the location of problems for each section (such as UL air, backhaul+Core network, inter eNB, and DL air section).

VoMA  SYSTEM OPERATION How to Activate VoMA UE Trace 

Register the signal trace in LSM for testUE.

VoMA

VoMA  Attach call and Check the TRACE ID In InitialContextSetupReq. ( First 6 digits are PLMN, next 6 digits are ID)

 Or check the TRACE ID(trace reference) in eccb log

VoMA  Change the TRACE ID low 6 digit from hexadecimal value to decimal  Configure Trace ID(PLMN + ID) using CHG-VOMA-UE CLI command.

 Configure external FTP server for upload the VOMA logs using CRTE-FTM-CONF CLI command.

VoMA  Attach call and Check the logs store to external FTP server every 1 min.

VoMA CHG-VOMA-CELL/RTRV-VOMA-CELL

VoMA How to Activate VoMA UE Trace  EQUIP the VOMA_USAGE using CHG-VOMA-CELL CLI command.

VoMA  Configure external FTP server for upload the VOMA logs using CRTE-FTM-CONF CLI command.  Attach the UE in network which configure VOMA and then make the VoLTE call.  Check the logs getting generated in FTP server every 1 min.

VoMA CHG-VOMA-CELL/RTRV-VOMA-CELL

VoMA Analysis    

Download the Octave software and install in remote PC Download the VoLTEAnalysis.zip (provided to TAC2) Copy all the pdcp logs and rlc logs to Logs folder (which is present inside the VoLTEAnalysis folder) Run the octave tool and set the path to VoLTEAnalysis folder as shown in the below figure

VoMA Analysis 

Run the script Run_VoLTEAnalysis.m - Right click on it and then click run as shown in the figure

VoMA Analysis 

Logs as shown below will be displayed on the command window

VoMA Analysis 

Excel files which contains Volte call quality metrics will be generated in the Results folder.

Note  

To have end(MO call) to end(MT Call) analysis, both the MO and MT UE should be registered for VOMA trace For Octave to generate results in the excel file, *.pdcpConfig log file is mandatory along with *.pdcpTraffic and *.rlcTraffic log files (sent by PDCP to VOMA server)

LTE MIMO Operation

MIMO Types MIMO MIMO

Data DataTransmission Transmission 1. Beam-Forming (Pre Coding) 2.

Spatial Multiplexing (Open or C lose Loop)

3. Diversity Coding 4.

SDMA (Spatial Division multiple access)

Number Of Antennas

Number Of Users

1. SISO (Single input single output) 2.

SIMO (Single input multiple output)

3.

MISO (Multiple input single output)

4.

MIMO (Multiple input Multiple output)

1. SU-MIMO (Single User MIMO) 2. MU-MIMO (Multi User MIMO)

MIMO Types(Data Transmission)

Spatial Multiplexing UE1

• Multiple, parallel data streams to single user (Open as well as Close Loop)

eNodeB

Spatial Multiplexing

Transmit Diversity UE2 eNodeB

Transmit Diversity

• Multiple copies of same stream to single user

MIMO Types (Number of Antennas)

a) SISO : Single Input Single Output Output c) MISO : Multiple Input Single Output Output

b) SIMO : Single Input Multiple

d) MIMO: Multiple Input Multiple

LTE Physical Layer Modules

Transmit Diversity – SFBC

Spatial Multiplexing Layers – Multiple data streams transmitted at the same time and Frequency Closed loop implies feedback from UE about the precoding matrix to be used.

Closed Loop Spatial Multiplexing RI – Rank Indicator determines the number of layers that can be supported by the current channel at the UE. PMI – Pre-coding Matrix Indicator; Selection of matrix from a codebook. CQI – indicates the combination of modulation scheme and coding rate

Open loop Spatial multiplexing No Pre-coding related feedback is sent from UE RI and CQI feedback is still sent from UE Any precoding from the allowed set can be used. CDD (TM 3) is the example of Open loop spatial multiplexing.

PMI, RI and CQI Feedback Information

PMI : Precoding Matrix Indicator (1 to 16) RI : Rank Indicator (1 to 4) CQI: Channel Quality Index (1 to 16)

Adaptive Rank Control

CQI and RI Information CQI Index

Modulation

0

Out of Range

1

QPSK

2

QPSK

3

QPSK

4

QPSK

5

QPSK

6

QPSK

7

16 QAM

8

16 QAM

CQI Index

Modulation

9

16 QAM

10

64 QAM

11

64 QAM

12

64 QAM

13

64 QAM

14

64 QAM

15

64 QAM

MIMO Type

RI (Rank Index)

SISO (TX Diversity)

1

SU- MIMO

2,3,4

4X4 MIMO

2,3,4

MIMO Modes in LTE systems Transmission Mode Mode 1

Mode 2

Mode 3

Mode 4

Mode 5

Mode 6

Mode 7

DCI format

DCI format 1A DCI format 1 DCI format 1A DCI format 1 DCI format 1A DCI format 2A DCI format 1A DCI format 2

DCI format 1A

DCI format 1A DCI format 1A DCI format 1

Search Space

Transmission scheme of PDSCH corresponding to PDCCH

Common and UE specific by C-RNTI

Single-antenna port, port 0

UE specific by C-RNTI Common and UE specific by C-RNTI

Transmit diversity

UE specific by C-RNTI Common and UE specific by C-RNTI UE specific by C-RNTI Common and UE specific by C-RNTI UE specific by C-RNTI Common and UE specific by C-RNTI Common and UE specific by C-RNTI Common and UE specific by C-RNTI UE specific by C-RNTI

Transmit diversity Large delay CDD Transmit diversity Close loop spatial Multiplexing Transmit diversity MU-MIMU Transmit diversity Close loop spatial Multiplexing , single layer

Single-antenna port, port 5

Carrier Aggregation

Carrier aggregation types

CARRIER AGGREGATION BANDWIDTH CLASS

AGGREGATED TRANSMISSION BW CONFIGURATION

NUMBER OF COMPONENT CARRIERS

A

≤100

1

B

≤100

2

C

100 - 200

2

CA user plane architecture

DL and UL primary component carrier. Secondary cells

Carrier Aggregation Scheduling Scheduling of resources on the PCell and SCell.

3 bit carrier indicator field.

DL Smart Scheduler

Samsung Solution -> “Smart” Scheduler Clever Techniques in assigning sub-carriers of the OFDMA physical layer to improve LTE Capacity

• Smart scheduler co-ordinates transmission pattern of eNB.

• Transmission pattern depends on UE data rate requirement © Samsung Electronics. All Rights Reserved. Confidential and Proprietary.

Smart Scheduler Option : C-RAN vs D-RAN

Radio Units

Optic

eN B

Smart Scheduler

Etherne t IP Network

EPC

- Optic based - Centralized Bank eNB - Real-time feedback

Smart Scheduler EPC

- Ethernet based - Distributed eNBs + Smart Scheduler - Backhaul delay (~30ms)

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Interference Measurement

2 Key Operations:

eNB 1 4

eNB 2

1

4

3

3

5

5 6

Smart Scheduler

1. Serving Cell Send SRS configurations to UE 2. SRS configuration for the UE is shared with other cells. 3. UE sends SRS 4. Serving and Neighbor eNBs estimates the SRS power signal. 5. Serving and Neighbor eNBs sends SRS power to Smart Scheduler. 6. Smart Scheduler sends the blanking pattern to interference eNB based on the UE bandwidth requirement.

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LTE Smart Scheduler Operations

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Message Flow - eNB Registration with Smart Scheduler Smart Scheduler

eNB 1. eNB_Smart Scheduler Registration Request (A6) (eNB ID, Cell ID, DL and UL Bandwidth, RS power, TDD configuration, ARFCN, RX antenna port etc.,)

2. eNB Smart Scheduler Registration response(A7) (Physical cell ID, Result)

0: Registration Success 4: SCHR_MAX_CAPA_DEREG 5: SCHR_INTERFACE_MISMATCH_DEREG 6: SCHR_RAN_MISMATCH_DEREG 7: SCHR_FRAMETYPE_MISMATCH_DEREG 8: SCHR_BW_SRS_MISMATCH_DEREG 9: SCHR_DSP_LINK_FAILURE_DEREG 10: SCHR_DEREG_MISC

3. SFN Request (A1) (eNB ID)

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Message Flow - eNB Registration with Smart Scheduler Smart Scheduler

eNB 4. SFN Response (A2) (eNB ID ,SFN)

5. Target SFN request (A3) eNB ID, Target SFN (coordination result target time)

6. Target SFN response (A4) eNB ID, Result

7. eNB start to send data Indication (A5) eNB ID, status

8. Start to send Data (…)

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Status Change Notification

LSM

Message flow during Normal operation Smart Scheduler

eNB 1. SRS resource allocation notification (B1) SRS resource Allocation info: eNB ID, Subcell ID, UE ID, SRS ID Message Periodicity : 320 ms. 4 Packets required for 600 UEs. 4 Packets / 320 ms

2. SRS Power notification message (B3) SRS resource Allocation info: eNB ID, Subcell ID, UE ID, SRS powers, Full Bandwidth SRS power Message Periodicity : 1 Pkts / 5 ms

3. Long term Notification message (B5) Total Number of Bearers, Edge Bearers, Non-Edge Bearers, UID, Average NI value Message Periodicity: 320 ms. 2 Packets required for 600 UEs

4. Long term Power notification message (B12) UE ID, bRetxFlag, uAidSubcellBitmap, uAverageTput, uCqiMpr, uRankIdx, uSpsUeFlag, uUid Message Periodicity : 1 Pkts / 5 ms

5. Short term indication message (B7) Blank Pattern distribution Message Interval: 5ms

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Pre-BO concept Concept of informing actual buffer occupancy value to Smart Scheduler. Get the Buffer Occupancy value from RLC for each UE Based on the Blanking bit-map History, compute the number of subframes in which eNB transmits in next 30 frames Compute maximum data rate per TTI for each UE Pre-Bo size = Actual BO size – Amount of data will be transmitted with-in 30 subframe No

Yes If Pre-BO size > 0

Normal Operation

Report to Smart Scheduler

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Pre-BO concept : Sample scenario

Concept of informing actual buffer occupancy value to Smart Scheduler. System Frame Number = 10738 PatternPeriod = 5 Position = 10738 % 5 = 3 Bit Positions - 3, 8, 13, 18, 23, 28 HistoryBitMap = 116 = 0000 0000 0000 0000 0000 0000 0111 0100 BitCount = 1 DS = BitCount*PatternPeriod = 1*5 = 5 PreBo = 33334 PreBo = mask15(PreBo)<<(mask1(PreBo>>15)*6) = 36224 BlankMpr = 11329 MaxRate = 13729 Count = (36224 + 13729 - 1)/13729 = 3 if(36224 > 3*13729) = if(36224 > 41187) which if false, thus PreBo = 0 and DS = 5 - 3 = 2 Thus, pCandidatePdu->uPreBo=uPreBo = 0 Thus, this candidate is not being raised to smart server Here, only those candidates are raised to the smart server for which the Prebo is greater than the MaxRate*Count(NonBlank opportunity) or the calculated DS value is 0.

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De-Registration Message Flow Smart Scheduler

eNB

De-registration request (A8) (Content of this message is same as registration request message, except registration flag)

De-registration response (A9) Result Field Consists of : 0: DeReg Success 4: SCHR_MAX_CAPA_DEREG 5: SCHR_INTERFACE_MISMATCH_DEREG 6: SCHR_RAN_MISMATCH_DEREG 7: SCHR_FRAMETYPE_MISMATCH_DEREG 8: SCHR_BW_SRS_MISMATCH_DEREG 9: SCHR_DSP_LINK_FAILURE_DEREG 10: SCHR_DEREG_MISC 255: Dereg Failed

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Uplink Smart Scheuler

UL Smart Scheduling Principles and objective The main objective of new LTE UL smart scheduling is to improve the performance of edge UE by reducing/decreasing the IoT value experienced by the edge UE through UL interference control between cells  Coordinated Scheduling using start RB index This is for avoiding cell interference by determining only the start direction of the RB allocation for each cell in the RT-scheduler without considering the limitations of the allocation of resources associated therewith and Edge region  Coordinated Scheduling using edge pattern Create a different edge area between cells which is in interference relation in order to avoid interference between cells by executing UL scheduling so that edge UE does not use RB of same position simultaneously

Coordinated Scheduling using start RB index Execute the coordination so as to be different Start RB index between the cells with interference relationship

RB allocation direction of cell #0/#1

Cell #0

UE 0 (Center)

UE 1 (Edge)

Conventional scheduling

High interference

Cell #1

UE 2 (Center)

UE 3 (Edge)

Frequency

Perform the allocation of UL resources considering Start RB index in each cell

RB allocation direction of cell #0 (Start RB index = 0) Lowest RB Index

Cell #0

If Start RB index = 0, it will be preferentially allocated from the lowest RB index

UE 0 (Center)

UE 1 (Edge)

Low interference

Cell #1

UE 2 (Center)

Low interference UE 3 (Edge)

Highest RB Index RB allocation direction of cell #1 (Start RB index = 1)

UL CS (Start RB Coordination)

Coordinated Scheduling using edge pattern Execute UL coordination so that different area (edge RB start position and edge RB number) is created between Cells which is in interference relation When allocating resources from the RT scheduler, perform the allocation of resources considering the edge area of cell which is in interference relation

Edge UE 끼리 동일 위치의 RB 사용으로 인해 서로 심한 간섭 RB index

RB 할당 위치 변경을 통해 edge UE 간섭 완화

subcell #0

subcell #1

subcell #0

subcell #1

E E E E C C C C

E E E E C C C C

E E E E C C C C

C C C C E E E E

E

E UL SINR 변화

C

LTE UL smart scheduling 적용 시 edge UE 영역 구분

Edge UE에 할당된 RB

C Center UE에 할당된 RB

간섭 감소로 인해 UL SINR 개선

E

C

Subcell #0 edge UE 영역

Subcell #1 edge UE 영역

CS model of UL smart scheduling CS mode 1

CS mode 2

CS mode 3

CS operation Edge pattern coordination

Edge pattern coordination

Start RB coordination

Operation c ell

Partial loading cell without full b uffer UE

Partial loading cell with full buffe r UE

Full loading cell

The edge start position and edge size Smart sched shall be uler operati determined by deciding the color bet on ween Full loading cell

Color judgement, and edge start Decide start RB index using the c position and olor edge size judgement by consider index determined in correspond ing the entire ing cell cell

RT-schedule Execute the allocation of Edge pattern Execute the allocation of Edge p r -based attern-based operation resources resources

Determine only the allocation di rection of resources considering the Start RB index. and execute the allocation of res ources of same method as existi ng UL macro scheduling

CS mode 1 basic operation and principles CS mode1 shall perform the allocation of resources considering the edge pattern (edge start position and edge RB size) determined by executing coordination between full loading cell

CS mode 2 basic operation and principles CS mode2 shall perform resource allocation considering the edge pattern ( edge RB start position and edge RB size) like the CS mode 1.

CS mode 3 basic operation and principles In case of partial loading cell , CS model 3 operates in the cell where full buffer UE exists

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