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ANR Management25th January, 2012HUAWEI TECHNOLOGIES CO., LTD.HUAWEI TECHNOLOGIES Co., Ltd.www.huawei.comHUAWEI Confidential 1ObjectiveThe object of below slides is to describe the ANR management for LTE system.Overview of ANRANR is a self-optimization function. It automatically maintains the integrity and effectiveness of Neighbor Cell Lists (NCLs) to increase handover success rates and improve network performance. In addition, ANR does not require manual intervention, which reduces the costs of network planning and optimization.

Concept related to ANRClassificationBased on neighbor relations, ANR is classified into intra-RAT ANR and inter-RAT ANR

Neighbor list management

NCL Neighbor cell listNRT Neighbor relation tableTempNRT Temporary NRTHO Blacklist Handover black listHO Whitelist Handover white listPCI Physical cell IDAbnormal Neighboring Cell Coverage

Neighbor list managementNCL

An NCL contains the information about the neighboring cells of a cell. Each cell has an intra-RAT NCL and inter-RAT NCLs. An NCL includes the E-UTRAN Cell Global Identifiers (ECGIs), PCIs, and E-UTRA Absolute Radio Frequency Channel Numbers (EARFCNs) of the neighboring cells. The eNodeB adds newly detected neighboring cells to the NCL.

NRTAn NRT contains the information about the neighbor relations between a cell and its neighboring cells. NRTs are classified into intra-RAT NRTs and inter-RAT NRTs. Each cell has an intra-RAT NRT and inter-RAT NRTs.

TempNRTA TempNRT is a temporary NRT. It has the same data structure as the NRT. Each cell has an intra-RAT TempNRT but does not have an inter-RAT TempNRT. After detecting a new intra-RAT neighbor relation, the eNodeB adds it to the intra-RAT TempNRT. Then, the eNodeB regularly analyzes the neighbor relation in the TempNRT. If the new neighbor relation is normal, the eNodeB adds it to the intra-RAT NRT.

Neighbor list managementHO Blacklist

An HO black list contains the information about neighbor relations that cannot be removedautomatically from the NRT by ANR or used for a handover. The neighbor relations in the HO Black list must meet the following conditions:

NO Remove = TRUENO HO = TRUE

HO Whitelist

An HO white list contains the information about neighbor relations that cannot be removed automatically from the NRT by ANR but can be used for a handover. The neighbor relations in the HO white list must meet the following conditions:

NO Remove = TRUENO HO = FALSE

Neighbor list managementPCI

A PCI is the identifier of a physical cell. A maximum of 504 PCIs are supported, therefore, PCI collisions occur inevitably.

The PCI of an E-UTRAN cell corresponds to:The Primary Scrambling Code (PSC) of a UTRAN FDD cellThe cell ID of a UTRAN TDD cellThe Base Station Identity Code (BSIC) of a GERAN cellThe Pseudo Number (PN) offset of a CDMA2000 cell

Abnormal Neighboring Cell Coverage

Abnormal neighboring cell coverage refers to the coverage of a cell that is not adjacent to the serving cell but can be detected by a UE in the serving cell. The eNodeB regards this cell as a neighboring cell of the serving cell and therefore attempts to add the neighbor relation to the NRT. The signals of an abnormal neighboring cell are generally unstable and therefore the success rate of handovers to this cell is low.

Procedure for detecting a missing neighboring cellThe source eNodeB delivers the measurement configuration to the UE and requests the UE to measure neighboring cells that meet the measurement configuration The UE detects that the PCI of cell B meets the measurement configuration and reports it to the source eNodeB. Then, the source eNodeB checks whether the NCL of cell A includes the PCI of cell B. If yes, the procedure ends. If no, the following steps continue.3) The source eNodeB instructs the UE, using the newly discovered PCI as a parameter, to read the ECGI, Tracking Area Code (TAC), and Public Land Mobile Network (PLMN) ID list of cell B.4) The source eNodeB schedules appropriate idle periods to allow the UE to read the ECGI, TAC, and PLMN ID list of cell B over the broadcast channel (BCH).5) The UE reports the detected ECGI, TAC, and PLMN ID list of cell B to the source eNodeB.