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1、诺基亚异频负载均衡报告 诺基亚北京项目LTE优化组2016年3月目录1.背景22.负载均衡功能测试32.1异厂家负载均衡功能测试32.1.1参数设置42.1.2实验效果62.2同厂家同站双载波负载均衡功能测试82.1.3参数设置92.1.4实验效果103.遗留问题111. 背景在LTE中，由于小区半径的减少，用户分布不均匀的现象十分严重，经常会出现某个小区负载较重而其邻居负载较低的现象，不仅会降低网络容量而且还会影响到用户的服务质量。上述原因直接促使了负载均衡技术的诞生，在保证用户的服务质量的同时，使网络总容量达到最大化。目前所支持的负载均衡功能如下：Ø iFLB：Inter Fre
2、quency Load Balance 异频负载平衡当高负荷小区的负荷超过High Load门限后进入iFLB激活状态，并可以触发LB切换，直到小区负荷低于Target load门限，则退出iFLB激活状态；在iFLB激活状态期间，ENB间的负荷信息不通过X2接口进行交互，所以这种状态下触发的LB切换属于邻区负荷未知的盲切换，只要目标邻区的下行rsrp大于设定的LNHOIF:thresholdRsrpIFLBFilter参数门限就会触发。而当切换请求消息(Handover Request Cause: Reduce Load in Serving Cell)发送给异频的目标邻区时如果邻区负荷已
3、经超过了自己小区设置的Target Load门限的话，邻区会拒绝该切换请求。Ø AMLE：Active Mode Load Equalization主动模式负载均衡小区开通AMLE功能后，当小区的负荷门限高于High Load的时候，小区会触发和异频邻区的负荷信息交换，它通过X2连接获取邻区的CAC信息(即邻区的综合可用容量)，当主小区和异频邻区负荷满足如下条件时触发AMLE的LB切换： 当邻区可用容量与本小区的可用容量差值大于设定参数门限AMLEPR:deltaCac时则触发LB的切换 主小区的可用容量<AMLEPR:maxCacThreshold 邻区的可用容量>=
4、AMLEPR:cacHeadroom UE检测到的目标邻区的下行rsrp大于设定的LNHOIF:thresholdRsrpIFLBFilter参数门限iFLB与AMLE的区别：iFLBAMLE当小区达到高负载门限时，iFLB 提供负载均衡AMLE将小区与配对邻区的负载差异控制在所设的负载差值以内iFLB的目的是把小区的负载控制在所设的负载门限下，而不是平衡小区间的负载候选邻区的筛选过程类似iFLB负载的信息只在同个eNB的小区间分享；对于不同eNB小区使用的是盲切换，不根据邻区的负载情况来判断小区间使用资源状态报告(RSR)来分享负载情况，不使用盲切换，对于没有RSR的邻区将不会被切换2. 负
5、载均衡功能测试2.1 异厂家负载均衡功能测试为进行Nokia和 HW LTE 基站间负载均衡的实验，选定实验点为首都机场T1出发厅。如下图所示，涉及到的Nokia小区为朝阳机场T1F2至F3层公共区NLM（ENB ID：76309），涉及到的HW基站为顺义首都机场T1航站楼F2F3东侧办公餐饮区及出港大厅HLM 499769-132。2.1.1 参数设置Ø 开启feature LTE1531: Inter-frequency Load Balancing Extension（开启iFLB）Parameter NameParameter Full NameMOC默认值修改值03019:
6、0613：00修改值0226-210:4511:30修改值0226-110:0010:30actInterFreqLBActivation of inter frequency load balancing (iFLB)LNBTSfalseTRUETRUETRUEthresholdRsrpIFLBFilterInter-Frequency LB Threshold for RSRP Target FilterLNHOIF-98-95-95-95thresholdRsrqIFLBFilterInter-Frequency LB Threshold for RSRQ Tar
7、get FilterLNHOIF-12-12-12-12targetLoadGbrDlDL GBR resource target loadLNCEL50505050targetLoadNonGbrDlDL non-GBR resource target loadLNCEL75755%8%targetLoadPdcchPDCCH target loadLNCEL503%50%5%iFLBHighLoadGBRDLInter-Frequency Load Balancing DL GBR High LoadLNCEL60606060iFLBHighLoadNonGBRDLInter-Freque
8、ncy Load Balancing DL non-GBR High LoadLNCEL85858%10%iFLBHighLoadPdcchInter-Freq Load Balancing PDCCH High LoadLNCEL805%80%7%nomNumPrbNonGbrNominal number of PRBs for load balancingLNCEL1101010iFLBBearCheckTimerInter-Frequency Load Balancing QCI1 Bearer Check TimerLNCEL12121212prohibitLBHOTimerProhi
9、bit Load Based Handover TimerLNCEL10101010iFLBRetryTimerInter Freq Load Bal Retry TimerLNCEL60606060Ø 开启feature LTE1841: Inter-Frequency Load Equalization（开启AMLE）MO ClassParameter NameParameter Full Name默认值修改值3月1日16:39:00LNBTSactIfHoEnable interFrequency handoverenabledenabledLNBTSactAmleActiva
10、te active mode load equalizationfalseTRUELNBTSactInterFreqLBActivation of inter frequency load balancing (iFLB)falseTRUELNBTSprohibitLBHOTimerProhibit Load based handover timer1010LNRELamleAllowedActive mode load equalization allowedfalseTRUELNRELremoveAllowedRemove allowedtrueFALSELNHOIFthresholdRs
11、rpIFLBFilterInter-freq load bal threshold for RSRP target filter-98-95LNHOIFthresholdRsrqIFLBFilterInter-freq load bal threshold for RSRQ target filter-12不设置LNCELcellResourceSharingModeCell resource sharing modenonenoneLNCELthreshold2InterFreqThreshold th2 interFreq for RSRP-100-90LNCELthreshold2aTh
12、reshold th2a for RSRP-96-87LNCELiFLBRetryTimerInter Freq Load Bal Retry Timer6060sLNCELiFLBHighLoadGBRDLInter-frequency load balancing GBR high load DL6060%LNCELiFLBHighLoadNonGBRDLInter-frequency load balancing non-GBR high load DL858%LNCELiFLBHighLoadPdcchInter-frequency load balancing PDCCH high
13、load8080%LNCELiFLBBearCheckTimerInter-frequency load balancing QCI1 Bearer check timer1212sLNCELcellCapClassCell capacity class value100100LNCELtargetLoadGbrDlDL GBR resource target load5050%LNCELtargetLoadNonGbrDlDL non-GBR resource target load755%LNCELtargetLoadPdcchPDCCH target load5050%LNCELmlbE
14、icicOperModeMode for calculating the CAC in load bal. and eICICallUesallUesLNCELnomNumPrbNonGbrNominal number of PRBs for load balancing110LNCELulStaticCacStatic CAC for uplink100100LNCELulCacSelectionUplink CAC source selectionulReflectDlCaculReflectDlCacLNCEL-AMLEPRamlePrIdamlePrId0/10LNCEL-AMLEPR
15、deltaCacDifference in CAC of source and target cells205%LNCEL-AMLEPRcacHeadroomHeadroom in CAC00LNCEL-AMLEPRtargetCarrierFreqTarget carrier frequency39148LNCEL-AMLEPRmaxCacThresholdThreshold for maximum CAC1001002.1.2 实验效果Ø 开启feature LTE1531: Inter-frequency Load Balancing Extension（开启iFLB）开启fe
16、ature LTE1531后，指标统计Nokia76309-1和HW 499769-132基于iFLB的LB HO全部成功，信令显示触发原因为reduce-load-in-serving-cell，符合预期。SDATETIMEENB_CELLHO_LB_ATTHO_LB_SUCCHIGH_CELL_LOAD_LB276309-11118276309-14425276309-17732276309-1282891276309-13316276309-11111276309-133252 76309_133282 76309_143432152 76309_188622 76309_10042 7
17、6309_111142 76309_187222 76309_151441462 76309_12016802 76309_11615712 76309_121102 76309_152401702 76309_177332 76309_12017622 76309_12113Ø 开启feature LTE1841: Inter-Frequency Load Equalization（开启AMLE）开启feature LTE1841后，指标统计LB HO有尝试计数，信令显示触发原因也为reduce-load-in-serving-cell，但同时也开启了iFLB，为了区分LB基于具体
18、feature，抓取wireshark，Nokia小区有发起资源请求，但未出现厂家间资源信息交互。SDATETIMEENB_CELLHO_LB_ATTHO_LB_SUCCHIGH_CELL_LOAD_LB276309_1000276309_1000276309_14736156276309_15546229276309_1000276309_100076309向HW小区发起的资源请求消息类型为Composite Available Capacity Periodic，周期性综合可用容量。IE/Group NamePresenceRangeIE type and referenceSemanti
19、cs descriptionCriticalityAssigned CriticalityReport CharacteristicsOBITSTRINGEach position in the bitmap indicates measurement object the eNB2 is requested to report.YESreject(SIZE(32)First Bit = PRB Periodic,Second Bit= TNL load Ind Periodic,Third Bit = HW Load Ind Periodic,Fourth Bit =
20、Composite Available Capacity Periodic.Bits 5 to 32 shall be ignored by the eNB22.2 同厂家同站双载波负载均衡功能测试为进行Nokia同站内各载波间负载均衡的实验，选定实验点为76413朝阳机场2号航站楼出发厅南侧NLM，该站点两个载波业务量和用户数分布不均。2.1.3 参数设置开启feature LTE1841: Inter-Frequency Load Equalization（开启AMLE）MO ClassParameter NameParameter Full Name默认值修改值3.2 10：00LNBT
21、SactIfHoEnable interFrequency handoverenabledenabledLNBTSactAmleActivate active mode load equalizationFALSETRUELNBTSactInterFreqLBActivation of inter frequency load balancing (iFLB)FALSEFALSELNBTSprohibitLBHOTimerProhibit Load based handover timer1010LNRELamleAllowedActive mode load equalization all
22、owedFALSETRUELNRELremoveAllowedRemove allowedTRUEFALSELNHOIFthresholdRsrpIFLBFilterInter-freq load bal threshold for RSRP target filter-98-90LNHOIFthresholdRsrqIFLBFilterInter-freq load bal threshold for RSRQ target filter-12不设置LNCELcellResourceSharingModeCell resource sharing modenonenoneLNCELthres
23、hold2InterFreqThreshold th2 interFreq for RSRP-100-90LNCELthreshold2aThreshold th2a for RSRP-96-87LNCELiFLBRetryTimerInter Freq Load Bal Retry Timer6060sLNCELiFLBHighLoadGBRDLInter-frequency load balancing GBR high load DL6060%LNCELiFLBHighLoadNonGBRDLInter-frequency load balancing non-GBR high load
24、 DL858%LNCELiFLBHighLoadPdcchInter-frequency load balancing PDCCH high load8080%LNCELiFLBBearCheckTimerInter-frequency load balancing QCI1 Bearer check timer1212sLNCELcellCapClassCell capacity class value100100LNCELtargetLoadGbrDlDL GBR resource target load5050%LNCELtargetLoadNonGbrDlDL non-GBR reso
25、urce target load755%LNCELtargetLoadPdcchPDCCH target load5050%LNCELmlbEicicOperModeMode for calculating the CAC in load bal. and eICICallUesallUesLNCELnomNumPrbNonGbrNominal number of PRBs for load balancing110LNCELulStaticCacStatic CAC for uplink100100LNCELulCacSelectionUplink CAC source selectionu
26、lReflectDlCaculReflectDlCacLNCEL-AMLEPRamlePrIdamlePrId0/10LNCEL-AMLEPRdeltaCacDifference in CAC of source and target cells205%LNCEL-AMLEPRcacHeadroomHeadroom in CAC00LNCEL-AMLEPRtargetCarrierFreqTarget carrier frequency39148LNCEL-AMLEPRmaxCacThresholdThreshold for maximum CAC1001002.1.4 实验效果修改后7641
27、3两载波用户数实现均衡，1小区用户数下降，PRB利用率下降，同时11小区用户数增加，PRB利用率有所上升。由于是站内切换无明显log显示LB HO，但切换事件均为LB切换的所用事件A4，符合预期。SDATETIMEENB_CELLHO_LB_ATTHO_LB_SUCCHIGH_CELL_LOAD_LB2 76413_10002 76413_10002 76413_10002 76413_10002 76413_10002 76413_10002 76413_10002 76413_10002 76413_113813702 76413_112011802 76413_117216902 764
28、13_123723702 76413_124324002 76413_126426202 76413_121020502 76413_120720302 76413_114614202 76413_114013902 76413_115615402 76413_123022802 76413_119719602 76413_121921102 76413_121621502 76413_122221802 76413_116816502 76413_117116802 76413_112512202 76413_116216102 76413_121721402 76413_123323102
29、 76413_125124502 76413_125124002 76413_125825102 76413_128528102 76413_121421302 76413_129328902 76413_125224802.3 空闲态负载均衡2.1.5 参数设置参数名参数全称级别默认值3月15日14：213月15日12:163月15日9：16actIdleLBActivation of idle mode load balancing (IdleLB)LNBTSFALSETRUETRUETRUEidleLBCapThreshIdle mode load balancing capacity
30、thresholdLNCEL100100100100idleLBPercentageOfUesPercentage of UE for idle mode load balancingLNCEL070%70%90%idleLBCelResWeightCell reselection weight factor idle mode load balancingLNCEL空空空空idleLBEutCelResWeightEUTRA carrier weight factor idle mode load balancingIRFIM空10070702.1.6 实验效果2个载波用户数相当，实现均衡。
31、PERIOD_START_TIMEenb_lcr76413-1CELL_LOAD_ACT_UE_MAXenb_lcr76413-11CELL_LOAD_ACT_UE_MAX2016/3/15 9:0076413-14176413-11382016/3/15 9:1576413-14376413-11392016/3/15 9:3076413-13876413-11352016/3/15 9:4576413-14076413-11372016/3/15 10:0076413-14276413-11402016/3/15 10:1576413-14076413-11392016/3/15 10:3
32、076413-13676413-11352016/3/15 10:4576413-14176413-11352016/3/15 11:0076413-14476413-11362016/3/15 11:1576413-14676413-11502016/3/15 11:3076413-14676413-11452016/3/15 11:4576413-16176413-11532016/3/15 12:0076413-16276413-11562016/3/15 12:1576413-16176413-11582016/3/15 12:3076413-16976413-11632016/3/1
33、5 12:4576413-16276413-11652016/3/15 13:0076413-17076413-11692016/3/15 13:1576413-16476413-11652016/3/15 13:3076413-16776413-11662016/3/15 13:4576413-16476413-11652016/3/15 14:0076413-15776413-11632016/3/15 14:1576413-15676413-11552016/3/15 14:3076413-15876413-11572016/3/15 14:4576413-15576413-115220
34、16/3/15 15:0076413-16176413-11562016/3/15 15:1576413-15676413-11582016/3/15 15:3076413-15776413-11612016/3/15 15:4576413-16376413-1156信令中rrcConnectionRelease消息中携带idleModeMobilityControlInfo消息，消息中有频点的信息和优先级。符合预期。实验设置38950和39148之间均衡，在idleModeMobilityControlInfo中这2个频点的优先级最高。3. 遗留问题在异厂家负载均衡实验中，基于AMLE并未成功，HW小区未回复负荷信息，需要进行进一步实验。15 / 15文档可自由编辑打印