Load Balance

Content

Feature Description Function Introduction Load Evaluating Factors Load Balance in Initial RRC Procedure Load Balance in RAB Assignment Load Balance in Call Holding Procedure

Function Introduction

Why to Perform Load Balance Deploy the inter-cell traffic appropriately Enhance the system capacity and QoS

What Load to Balance Uplink interference (RTWP) Downlink power (TCP) Downlink code resources

When to Perform Load Balance Initial RRC procedure RAB assignment procedure Call holding procedure

Where to Perform Load Balance Intra-system or Inter-RAT neighboring cell configured (ShareCover,

GsmShareCover)

Content

Feature Description Function Introduction Load Evaluating Factors Load Balance in Initial RRC Procedure Load Balance in RAB Assignment Load Balance in Call Holding Procedure

Load Evaluating Factors

Three evaluating factors: uplink interference, downlink power, and downlink code resources Switches: UlLdBalPwrSwch, DlLdBalPwrSwch, and

LdBalCdSwch Weight: DlLdBalPwrWeight, UlLdBalPwrWeight, and

LdBalCdWeight Threshold: DlLoadNeedBal2U, UlLoadNeedBal2U, and

DlCdLdNeedBal2U Difference: ExtraCDeltaTrd, ExtraCDeltaTru, and

ExtraCDeltaCdTrd

Uplink interference

Uplink payload = Load generated by uplink DCH +

Load generated by non-scheduling E-DCH

+

Load generated by the throughput of GBR services of scheduling E-DCH

Downlink power

0

NOHSDSCHPower HSDSCHRequiredPowerSnum

ii

downl i nk payl oad

Code resource

Code Usage=number of Non HS-PDSCH occupied

SF128+MinHspdschNum*128/16

Where,

MinHspdschNum = Max(MinHspdschNum in OMCR, MinHspdschNumbyGBR)

Coupling Operation of These Factors

k ： the number of factors opened for load Balance Loadi ： source cell-actual load subtracts Delta

target cells- the actual load ThrdLoadi ： load Balance threshold Weighti ： the weight of each factor The sum of weight of each factor is 1. If all three

factors are switched “OFF”, load Balance is not performed.

k

1iiii Weight*ThrdLoadLoadLoadWeight ）（

Content

Feature Description Function Introduction Load Evaluating Factors Load Balance in Initial RRC Procedure Load Balance in RAB Assignment Load Balance in Call Holding Procedure

Load Balance in Initial RRC Procedure

In case of: InitRrcLBSw switch is set to ON Serving cell reaches the threshold Neighbor cells with “Overlap” or “ Covers” Load balance, select cell with the lowest load to access

The neighbor cell must be same frequency band with original cell.

Load Balance in Initial RRC Procedure

F1 (HSPA)PS prefer

F2 (R99+HSPA)CS+PS prefer

UE camping

F1 (HSPA)PS prefer

F2 (R99+HSPA)CS+PS prefer

Content

Feature Description Function Introduction Load Evaluating Factors Load Balance in Initial RRC Procedure Load Balance in RAB Assignment Load Balance in Call Holding Procedure

Load Balance in RAB Assignment

In case of: RabAssLBSw switch is set to ON (for CS service,

CsBalSwch should be also considered) Serving cell reaches the threshold Neighbor cells with “Overlap” or “ Covers”

Load balance, select cell with the lowest load to access

Service properties and UE capabilities should be considered in selecting the target cell.

Load Balance in RAB Assignment

F1 (R99+HSPA)CS+PS prefer

F2 (R99)CS prefer

UE registers Voice call

F1 (R99+HSPA)CS+PS prefer

F2 (R99)CS prefer

HS call

Content

Feature Description Function Introduction Load Evaluating Factors Load Balance in Initial RRC Procedure Load Balance in RAB Assignment Load Balance in Call Holding Procedure

Load Balance in Call Holding Procedure

In case of CallHoldLBSw being set to ON, when: Handover, relocation from other system Handover, relocation from other RNC Call re-establishment triggered by CELL UPDATE State transition from non-CELL_DCH to CELL_DCH

Load balance, select cell with lowest load to access