大話務(wù)場景保障

大話務(wù)場景保障方案--Nokia--2017.02大事件保障流量預(yù)測定義服務(wù)策略擴(kuò)容開啟大事件相關(guān)功能參數(shù)優(yōu)化預(yù)演事前規(guī)劃Traffica實(shí)時(shí)監(jiān)控網(wǎng)絡(luò)數(shù)據(jù)及時(shí)定位問題，網(wǎng)絡(luò)優(yōu)化事中監(jiān)控小區(qū)容量復(fù)原恢復(fù)常規(guī)容量下的參數(shù)設(shè)置大容量事件的網(wǎng)絡(luò)KPI總結(jié)事后提高諾基亞大容量解決方案信令過載保護(hù)空閑狀態(tài)下的負(fù)載均衡連接狀態(tài)下的負(fù)載均衡過載保護(hù)RRC連接數(shù)=激活用戶數(shù)，更好的保證接入用戶的服務(wù)無法RRC接入本小區(qū)的用戶，使用負(fù)載遷移到其他小區(qū)負(fù)載分擔(dān)Traffica實(shí)時(shí)監(jiān)控網(wǎng)絡(luò)數(shù)據(jù)完善的counter統(tǒng)計(jì)，為網(wǎng)絡(luò)優(yōu)化提供保障實(shí)時(shí)監(jiān)控大容量情況下，KPI無明顯下降，正常提供業(yè)務(wù)智能調(diào)度成熟的硬件平臺，穩(wěn)定的架構(gòu)設(shè)計(jì)瞬時(shí)沖擊下，各項(xiàng)硬件指標(biāo)保持穩(wěn)定硬件穩(wěn)定針對大容量的特殊場景，有一套自有的優(yōu)化方案針對性優(yōu)化大話務(wù)場景保障方案大話務(wù)典型場景及特點(diǎn)容量規(guī)劃及覆蓋規(guī)劃大話務(wù)前參數(shù)配置建議大話務(wù)中重點(diǎn)關(guān)注的網(wǎng)管指標(biāo)及指標(biāo)異常的應(yīng)對措施LTE

Performance2013

Korea

PusanFireworks

Festival1.5

million

audience3

LTE

networksfrom3

vendors700,000

LTE

userNokiaCompanyBCompanyC3

h

45

mGood

LTE

service

qualityBadLTE

service

qualityNo

LTE

serviceUL

DLAvg

DL

speedMore

than

2XCompany

B,More

than

8XCompany

C8xNokia在2013韓國煙花節(jié)上是唯一能提供穩(wěn)定LTE服務(wù)的設(shè)備商399Busy

hour

Activeuser

/

cellAvg

UL

speedMore

than

5XCompany

B,More

than

9XCompany

C9xNetwork

Delay23%

short

thanCompany

B,85%

short

thanCompany

C85%NokiaTD-LTE網(wǎng)絡(luò)成功保障2014

上海F1賽事Max

cellactiveuser/

RRCconnectionAudiences（K）Max

active

userin

F1

area8481852:1Avg

DL

speed（Mbps）13.2192BusyeNodeBDL:ULratioBusy

hour

end

user

traffic

Model172

call/h

27MB/hBusy

hour

cellthroughput（GB)5.4Nokia

TD-LTE網(wǎng)絡(luò)成功保障2014

廈門陳奕迅演唱會Audiences30K+Max

activeuserinstadium649Busy

hour

cellthroughput（GB)10.16(DL)/8.4(UL)Max

cellactiveuser/RRCconnection289Nokia

TD-LTE網(wǎng)絡(luò)成功保障2014

廈門汪峰演唱會Audiences觀眾數(shù)3萬單小區(qū)最大激活用戶數(shù)400場館內(nèi)最忙時(shí)總數(shù)據(jù)流量（GB）—多小區(qū)8.81(DL)/3.4(UL)場館內(nèi)RRC最大連接數(shù)2414最忙小區(qū)峰值時(shí)間段下行數(shù)據(jù)量（GB）—單小區(qū)最忙小區(qū)ERAB成功率負(fù)載均衡成功保障小區(qū)間QoS大容量參數(shù)配置保障2.02

99.96%大事件保障給運(yùn)營商帶來新的挑戰(zhàn)(delete)Traffic激活用戶SignalingTraffic

ULCompetition

onnetwork

qualityNo.1€bnActiveUser10X+大話務(wù)典型場景及特點(diǎn)從以上大事件可以看出，大話務(wù)場景具有以下特點(diǎn)：相對密閉有限的空間容納遠(yuǎn)大于日常可容納的用戶數(shù)參與大事件的觀眾人數(shù)（10倍的用戶數(shù)）大事件過程中單小區(qū)的最大接入用戶數(shù)（10倍的用戶數(shù)）大事件區(qū)域的最大激活用戶數(shù)（10倍的用戶數(shù)）大事件發(fā)生時(shí)的話務(wù)激增（30倍的話務(wù)）大事件發(fā)生時(shí)的信令風(fēng)暴（20倍的信令）大事件發(fā)生時(shí)的上行數(shù)據(jù)吞吐量（40倍的上行數(shù)據(jù)吞吐量）下行數(shù)據(jù)吞吐量大話務(wù)場景保障方案大話務(wù)典型場景及特點(diǎn)容量規(guī)劃及覆蓋規(guī)劃大話務(wù)前參數(shù)配置建議大話務(wù)中重點(diǎn)關(guān)注的網(wǎng)管指標(biāo)及指標(biāo)異常的應(yīng)對措施覆蓋規(guī)劃（單獨(dú)做的規(guī)劃）對覆蓋的設(shè)計(jì)是多用戶并發(fā)接入重大事件保障方案的基礎(chǔ)，應(yīng)合理合適的調(diào)整保障區(qū)域的覆蓋。其中對覆蓋的調(diào)整包括RSRP的調(diào)整以及SINR的調(diào)整，可通過硬調(diào)整和軟調(diào)整兩種方式實(shí)現(xiàn)。其中硬調(diào)整是指對物理天線的調(diào)整，對于保障區(qū)域出現(xiàn)的覆蓋空洞以及干擾嚴(yán)重的區(qū)域，對物理天線方位角進(jìn)行調(diào)整，若出現(xiàn)覆蓋不到的區(qū)域可以考慮臨時(shí)加站的方式。軟調(diào)整是指對后臺參數(shù)的調(diào)整，如調(diào)整RS功率，工控相關(guān)參數(shù)等。備注：覆蓋測試及優(yōu)化是一線工程師對網(wǎng)絡(luò)交付的最基本保障，具體覆蓋要求需要一線工程師根據(jù)實(shí)際地形，基站情況進(jìn)行調(diào)整。室外連續(xù)覆蓋區(qū)域規(guī)劃標(biāo)準(zhǔn)不同場景類型及對應(yīng)的覆蓋指標(biāo)要求如下：類型穿透損耗覆蓋指標(biāo)(95%概率)邊緣用戶速率指標(biāo)（50%負(fù)載）（Mbps）RSRP門限（dBm）RS-SINR門限（dB）F頻段D頻段主城區(qū)高-100-98-31（Mbps）主城區(qū)低-103-101-31（Mbps）一般城區(qū)-103-101-31（Mbps）縣城及郊區(qū)-105-103-31（Mbps）注：根據(jù)建筑物穿透損耗將主城區(qū)分為高穿損、低穿損場景，高穿損場景指中心商務(wù)區(qū)、中心商業(yè)務(wù)、密集居民區(qū)等區(qū)域，其他區(qū)域?yàn)榈痛p場景。室外連續(xù)覆蓋區(qū)域規(guī)劃標(biāo)準(zhǔn)站間距與RSRP的關(guān)系根據(jù)目前的測試情況，基本發(fā)現(xiàn)如下規(guī)律，后續(xù)還將進(jìn)一步驗(yàn)證，不同站間距情況下，F(xiàn)/D頻段

RSRP的覆蓋能力如下：RS-SINR與業(yè)務(wù)下載速率的關(guān)系RSRP是系統(tǒng)允許接入的最低電平要求，與下載速率沒有直接對應(yīng)關(guān)系，而RS-SINR與下載速率之間有穩(wěn)定的對應(yīng)關(guān)系。50%加載自適應(yīng)場景下，用戶占用50RB時(shí)，RS-SINR與業(yè)務(wù)下載速率對應(yīng)關(guān)系如下站間距(米）密集城區(qū)(dBm)一般城區(qū)(dBm)縣城及郊區(qū)(dBm)F頻段D頻段F頻段D頻段F頻段D頻段350~400-93~-95-95~-97-90~-92-92~-94-89~-91-91~-93400~450-95~-97-97~-99-92~-94-94~-96-91~-93-93~-95450~500-97~-99-99~-101-94~-96-96~-98-93~-95-95~-97500~600-99~-101-101~-103-96~-98-98~-100-95~-97-97~-99600~700-101~-103-103~-105-98~-100-100~-102-97~-99-99~-101700~800-103~-106-105~-108-100~-103-102~-105-99~-102-101~-104RS-SINR(dB)-5-3-2-10369下載速率(Mbps)0.511.5235.58.512.5室內(nèi)覆蓋系統(tǒng)的規(guī)劃標(biāo)準(zhǔn)覆蓋類型覆蓋區(qū)域覆蓋指標(biāo)RSRP門限（dBm）RS-SINR門限（dB）室內(nèi)覆蓋系統(tǒng)一般要求-1056營業(yè)廳（旗艦店）、會議室、重要辦公區(qū)等業(yè)務(wù)需求高的區(qū)域-959注：對于室內(nèi)覆蓋系統(tǒng)泄漏到室外的信號，要求室外10米處應(yīng)滿足RSRP≤-110dBm或室內(nèi)小區(qū)外泄的RSRP比室外主小區(qū)RSRP低10dB(當(dāng)建筑物距離道路不足10米時(shí)，以道路靠建筑一側(cè)作為參考點(diǎn))。網(wǎng)絡(luò)優(yōu)化場景調(diào)節(jié)下傾角SINRSINR下傾角大:平均SINR高，干擾小，小區(qū)吞吐量提升但覆蓋面積減小下傾角小:平均SINR低，干擾大，小區(qū)吞吐量降低eNB

A,servingcelleNB

BeNB

A,servingcelleNB

BNoise

floorNoise

floor密集城區(qū)中，小區(qū)間的干擾是影響網(wǎng)絡(luò)性能的主要因素，而調(diào)節(jié)下傾角是優(yōu)化干擾的重要手段功控調(diào)整對比2014年采用新的保守功控策略，很好的控制了在高load下的PUSCH的RSSI，從而提升了

RACH/RRC建立成功率-97.0-97.5-98.0-98.5-99.0-99.5-100.0-100.5-101.0-101.5808182838485868788899091929394959697989910016:0017:0018:0019:0020:0021:0022:0023:00PUSCH

RSSI

[dB]Compl

RACH

stp

SR

LTE_1056D RRC

setup

success

rateAvg

PUSCH

RSSI,

LTE_5444B-82-84-86-88-90-92-94-96-983640444852566064687276808488929610016:00:0016:30:0017:00:0017:30:0018:00:0018:30:0019:00:0019:30:0020:00:0020:30:0021:00:0021:30:0022:00:0022:30:0023:00:0023:30:00PUSCH

RSSI

[dBm]Success

rate

[%]Success

rate

[%]Compl

RACH

stp

SR

LTE_1056A Total

E-UTRAN

RRC

conn

stp

SRLTE_5218CAvg

PUSCH

RSSI

LTE_5444B201420132013

:

increase

in

PUSCH

RSSI

is~9dB2014

:

increase

in

PUSCH

RSSI

is

~0.5dB容量規(guī)劃在事件發(fā)生前需要對當(dāng)前的網(wǎng)絡(luò)進(jìn)行容量計(jì)算獲得小區(qū)最大支持的用戶數(shù)，并且對保障時(shí)所需要支持的最大用戶數(shù)進(jìn)行預(yù)估計(jì)，并調(diào)整小區(qū)參數(shù)使得可以支持較多的用戶接入。與最大用戶數(shù)計(jì)算相關(guān)的參數(shù)配置如下：PUCCH

CQI資源配置：（簡單介紹）?LNCEL/actDrx，LNCEL/riPerM（RI上報(bào)周期），LNCEL/riPerOffset（RI上報(bào)位置）；?LNCEL/cqiPerNp（UE發(fā)送周期性CQI上報(bào)周期）；LNCEL/

nCqiRb（預(yù)留的PRB數(shù)用于發(fā)送周期性CQI）；每小區(qū)支持：?Drx關(guān)閉：nCqiRb*2（3:1配置，1幀中有2個(gè)上行幀）*6（PUCCH是碼分，每組設(shè)定6個(gè)用戶）*

cqiPerNp/10；?Drx打開時(shí)：nCqiRb*2（3:1配置，1幀中有2個(gè)上行幀）*3（PUCCH是碼分，每組設(shè)定6個(gè)用戶，Drx打開時(shí)用戶減半）*

cqiPerNp/10PUCCH

SR資源配置：LNCEL/

cellSrPeriod（UE發(fā)送SR的周期）LNCEL/

n1pucchAn（預(yù)留的PUCCH

Format

1資源用于發(fā)送SR）每小區(qū)支持：上行子幀數(shù)*

cellSrPeriod(ms)/10*n1PucchAn小區(qū)支持的最大用戶數(shù)為MIN（PUCCH

CQI最大用戶數(shù)，PUCCH

SR最大用戶數(shù)）流量預(yù)測流程流量估計(jì)和最忙小區(qū)估計(jì)前期經(jīng)驗(yàn)+用戶行為=流量增長趨勢準(zhǔn)備階段額外的站址/應(yīng)急通信方案及覆蓋優(yōu)化等實(shí)施建議參數(shù)和功能的預(yù)測試大事件保障方案定稿流量增長計(jì)算分析階段性能評估和容量瓶頸分析參數(shù)配置建議大事件保障方案初稿，包括硬件擴(kuò)容、覆蓋優(yōu)化、參數(shù)設(shè)

置等建議大事件大話務(wù)場景保障方案大話務(wù)典型場景及特點(diǎn)容量規(guī)劃及覆蓋規(guī)劃大話務(wù)前參數(shù)配置建議大話務(wù)中重點(diǎn)關(guān)注的網(wǎng)管指標(biāo)及指標(biāo)異常的應(yīng)對措施大話務(wù)場景參數(shù)設(shè)置（性能影響參數(shù)）參數(shù)配置時(shí)隙配比PRACH相關(guān)參數(shù)PDCCH相關(guān)參數(shù)PUCCH相關(guān)參數(shù)SRS相關(guān)參數(shù)算法相關(guān)參數(shù)配置PHICH參數(shù)配置參數(shù)優(yōu)化，提高接入用戶數(shù)特殊參數(shù)優(yōu)化（韓國例子highlight）Paramter

NameCurrent

Parameter

SetHigh

TrafficEventCommentsharqMaxTrDl55harqMaxTrUl57raContResoT64ms64msT300400ms600msharqMaxMsg355pdcchAggRaresp448

for

coverage

limited

cellsmaxCrRaDl0.120.120.05

for

coverage

limited

cells

(where

above

=

8)pdcchAggMsg444maxCrRa4Dl0.120.12ilReacTimerUl200ms0msdeltaPreMsg32dB2dBulpcRarespTpc4dB2dBconservative

power

control

scheme

(reference

in

next

page

)ulpcIniPrePwr-96dBm-104dBmconservative

power

controlscheme(reference

in

next

page

)prachPwrRamp2dB2dBpreambTxMax1010raSmallVolUl144bits56bits大話務(wù)場景保障方案大話務(wù)典型場景及特點(diǎn)容量規(guī)劃及覆蓋規(guī)劃大話務(wù)前參數(shù)配置建議大話務(wù)中重點(diǎn)關(guān)注的網(wǎng)管指標(biāo)及指標(biāo)異常的應(yīng)對措施大話務(wù)中重點(diǎn)關(guān)注的網(wǎng)管指標(biāo)及指標(biāo)異常的應(yīng)對措施根據(jù)現(xiàn)網(wǎng)數(shù)據(jù)分析發(fā)現(xiàn)，以下指標(biāo)在大話務(wù)場景下會比較敏感丟包率，棄包率，誤塊率，下行時(shí)延RRC連接建立成功率，RRC掉線率，E-RAB連接建立成功率，E-RAB掉線率小區(qū)流量小區(qū)最大用戶數(shù)小區(qū)平均用戶數(shù)上下行PRB利用率用戶感知備注：基于以上大話務(wù)場景比較敏感的網(wǎng)管指標(biāo)，NOKIA當(dāng)前的網(wǎng)絡(luò)擴(kuò)容方案所考慮的主要指標(biāo)就是上面其中的幾項(xiàng)網(wǎng)絡(luò)優(yōu)化接入性：RRC建立成功率

DRB建立成功率

E-RAB建立成功率

S1建立成功率可用性：小區(qū)在網(wǎng)率資源利用率上/下行吞吐率高質(zhì)性：平均CQI時(shí)延PDU重傳率保持性：RRC掉線率

DRB掉線率E-RAB掉線率移動性：eNB內(nèi)/外切換成功率

S1/X2切換成功率同/異頻切換成功率以上為NOKIA網(wǎng)絡(luò)優(yōu)化主要關(guān)注的方向，可通過軟優(yōu)化（如參數(shù)調(diào)整，功能開啟，新產(chǎn)品應(yīng)用等）及硬優(yōu)化（下傾角調(diào)整，方位角調(diào)整，RF優(yōu)化等）實(shí)現(xiàn)大事件網(wǎng)絡(luò)常見問題一：宕機(jī)A

meeting

with

>300

attendees2014.7.15,

Xi’an,

ChinaThe

base

station

was

crashed

during

the

meetingbecause

of

100%

CPU

load

caused

by

149

UEs.The

fact

shows

that

1

BBU

rack

can

only

support

lessthan

200

UEs

with

low

throughput

and

bad

KPIperformance.The

limited

CPU

capacity

and

non-qualified

softwareleads

to

an

inevitable

outage.120%100%80%60%40%20%0%80100120150180200RRC

setup

SR BBU

CPU

loadActiveUEThe

Same

eNB

problems

happenedagain

in

HaoShengYin

concert

andHengDa

football

game.大事件網(wǎng)絡(luò)常見問題二：KPI嚴(yán)重下降（接入成功率、上下行吞吐量）The

KPI

dropped

to

dramatically

low

level

rapidly

beforethe

active

UE

reaches

200;LTE

service

is

almost

unavailable

to

all

the

users,

even

thea

few

accessed

UEs;

e-RAB

setup

success

ration

is

below10%

during

the

whole

gig.ActiveUE

SRVocal

concertbeginsMBActiveUE2014.7.17

Changzhou,

China應(yīng)用場景大事件保障：主要用于對重點(diǎn)區(qū)域、重大事件活動進(jìn)行實(shí)時(shí)KPI跟蹤、監(jiān)控，并能第一時(shí)間處理。KPI問題精細(xì)分析：傳統(tǒng)網(wǎng)管KPI較粗，Traffica對于KPI問題可以細(xì)化到呼叫各階段及網(wǎng)元模塊/進(jìn)程級，對于分析疑難問題有很大幫助。小區(qū)跟蹤及預(yù)警：利用Traffica可以設(shè)置性能指針閥值的功能，對突發(fā)大量問題的小區(qū)進(jìn)行指標(biāo)預(yù)警，并實(shí)時(shí)轉(zhuǎn)化成告警供后臺處理。實(shí)時(shí)檢測網(wǎng)絡(luò)指標(biāo)Nokia具有一套完整的保障機(jī)制針對不同程度的擁塞Congestion

LevelHighLowParameterOptimizationSmart

SchedulerLoad

BalanceC-plane

OverloadHandlingCell

barAdmission

ControlPRACH

SR

MonitorstandardNokia’s

featureRRC

rejection通過監(jiān)控RACH

SR發(fā)現(xiàn)PRACH問題MSG4和MSG5需要增強(qiáng)的例子100%80%60%40%20%0%501015205:007:009:0011:0013:0015:0017:0019:0021:00RACH

Success

rate

%SINR

dBPUSCH

SINR

AVG RACH

Success

RateRRC

Setup

Success

Ratio100.0%99.0%98.0%97.0%96.0%95.0%100%

90%

80%

70%

60%

50%

40%RACH

Success

Ratio?RRC

setup

success

rate

follows

RACH

success

rate

as

shown

earlier?RACH

SR

and

RRC

setup

SR

collapses

rapidly

in

case

of

poor

UL

interference

conditionscausing

rapid

SINR

drop-Too

aggressive

power

control-Too

much

cell

overlapGains

achieved

with

parameter

optimizationMsg4

robustnessMsg5

robustness針對大事件的KPI優(yōu)化策略增強(qiáng)具體每一條信令的魯棒性，優(yōu)化KPIStrategy

of

KPI

optimizationincrease

MSG-3/MSG-5

(ConnectionSetup

Complete)

robustnessMSG-4

should

be

slightly

more

reliablethan

MSG-2MSG3:

deltapreamblems3=3dBMSG2/4:

8CCEMSG5:Uplink

Adaptive通過監(jiān)控RACH

SR發(fā)現(xiàn)PRACH問題MSG3需增強(qiáng)的例子100%90%80%70%60%50%40%30%20%10%0%09.26.2013…09.26.2013…09.26.2013…09.26.2013…09.27.2013…09.27.2013…09.27.2013…09.27.2013…09.28.2013…09.28.2013…09.28.2013…09.28.2013…09.29.2013…09.29.2013…09.29.2013…09.29.2013…09.30.2013…09.30.2013…09.30.2013…09.30.2013…10.01.2013…10.01.2013…10.01.2013…10.01.2013…10.02.2013…10.02.2013…LTE_5569ALTE_1056bLTE_5569a

=

#sent

msg2

from

eNB

/

#received

preamblesLTE_1056b=

#received

msg3

/

#received

preambles?Improvement

on

performancethrough

parameter

modifications?Msg2

–

robustness

for

PDCCH

andPDSCH?Msg3

–

robustness

for

PUSCHRACH

SRCSSRSSSR接入過程中各個(gè)環(huán)節(jié)的成功率監(jiān)測有利于盡快發(fā)現(xiàn)網(wǎng)絡(luò)問題接入過程中的counterRACH

Success

Ratio=

#receivedmsg3

/

#received

preamblesRRC

Connection

setup

successrate=

#received

msg5

/

#receivedmsg3Session

Setup

Success

Rate(SSSR)=

#

receivedRRCReconfiguration

/

#

received

mag3MSG1,2,3

是引起信令擁塞的主要原因隨機(jī)接入信令分析maxHARQ-Msg3Tx:

8

timesmac-ContentionResolutionTimer:maximum

64ms,if

timer

expires,

it

willre-send

MSG3?UE

will

re-attempt

randomaccess

manytimes(re-send

MSG1

and

MSG3)

if

UEfailed

RRC

connection

setup

which

causes

more

signaling

and

so

on

until

nothingworks?Monitoring

RACH

success

ratio

and

RACH

robustness

is

more

importantpreambleTransMax:

maximumnumber

of

preamble

transmissionis

200信令和數(shù)據(jù)基于不同的優(yōu)先級調(diào)度信令具有最高調(diào)度優(yōu)先級，防止信令擁塞PriorityCCCH:RACH

MSG2/3/4Re-Transmission:GBR/non-GBR,

nominal

BitRateDCCH:RRC

reconfig,

etc1st

Tx

GBR1st

TX

NBR1st

TX

nGBROther

bearers:

Still

available

PRB

afterall

above

resource

allocationPrioritized

signaling

resource

allocationDecrease

signaling

congestionHigh

radio

resource

efficiencyLow

latency

for

both

signaling

and

data接納控制僅對新接入請求進(jìn)行限制，不對已建立的承載進(jìn)行控制接納控制是否生效受限于門限的設(shè)置Initial

Context

Setup

RequestRRC

Connection

RequestMMEeNBRRC

Connection

SetupRRC

Connection

SetupCompleteNAS:

Service

RequestInitial

UE

MessageNAS:

Service

RequestRandom

Access

ProcedureRadio

Admission

ControlRadio

Admission

ControlNAS

Security

EstablishmentNAS:

Activate

defaultEPSbearer

context

requestStep1Step2&3Initial

Context

Setup

FailureNAS:

Activate

defaultEPSbearer

context

rejectRRC

Connection

ReleaseNAS:

Service

RejectUE

ContextReleaseNAS:

Service

Reject*

Thresholds

checking:Step

1-maxNumRRCStep

2-maxNumActUeStep

3-maxNumActDrbRadio

Admission

Control

has

three

mainsteps.

Number

of

RAC

steps

depends

onprocedure

and

UE

state:–

Attach

procedure

(step

1,2

and

3)Tracking

Area

Update

(TAU)

(step

1)Service

Request

(step

1,

2

and

3

or

only

3*)Handover

(step

1,

2

and

3)Admission

Control

does

not

verify

actualprocessing

load

to

prevent

system

from

theoverloadC-plane

OverloadHandling針對已建立的承載進(jìn)行過載保護(hù)

C-plane信令過載保護(hù)Bearer

ManagementSIBRRC

PagingrequestS1AP:

HandoverRequestRRC

ConnectionRequestRRC

Paging

PagingAdmission

ControlUECCELLCE.g.

of

some

messages

processed

byFSP?C-plane

Overload

Handling

trigger

overload

countermeasures

toreduce

processing

load?Overload

state

definedby:queuing

timenumber

of

signaling

messages

for

which

queuing

time

is

exceededpercentage

of

Global

buffer

in

use?Countermeasures

refer

to

rejecting

particular

RRC/S1AP/X2APrequests

which

depends

on

overload

stateRRC

connection

rejection

應(yīng)用于中度擁塞when

C-plane

overload

in

level

1

stageRRCConnectionRejectRRCConnectionRequestUEEUTRANRRCConnectionReject

will

giveawaitTime

to

UE

to

stop

reattempt,

themaximum

wait

time

is

16s?However,

sending

RRC

reject

with

waittime

as

MSG4

means

RACH

procedureisalready

completed,

which

meansthemsg1,2,3

and

4

are

all

simply

unnecessarysignalingCell

baring應(yīng)用于重度擁塞when

C-plane

overload

in

level

2

stageAC

Bar

broadcast

in

SIB2

which

willnotcause

any

unexpected

signalingAC

bar

have

parameters

to

enable

thebarring

per

certain

access

classes

andcertain

call

setup

probabilityac-barringfactor

used

for

block

users

fromsending

anything

(no

preambles

even)

withcertain

probabilityac-barringfactor

=

50%

,

it

means

that

eachuser

trying

to

initiate

RRC

setup

procedureswith

caus