关键词不能为空

当前您在: 主页 > 英语 >

LTE切换优化专题-全参数功能和优化思路

作者:高考题库网
来源:https://www.bjmy2z.cn/gaokao
2021-02-08 09:52
tags:

-

2021年2月8日发(作者:annoyed)


实用文档



内容


:参数 功能及设置、切换原理、信令流程、优化案例等。



1



LTE


切换原理



1.1



Intra- eNodeB


切换



触发事件:


A3


事件(同频切换)


A5


事件(异频切换)




UE


从当前所处的服务小区切换到同一


eNo deB


下的另一小区时,会发生


Intra- eNodeB


切换。



基于

< p>
X2


接口的切换



触发事 件:


A3


事件(同频切换)



A5


事件(异频切换)



当两个


eNodeB


之间存在


X2< /p>


接口时,


UE


从当前所驻留的服务小区切 换到另一


eNodeB


时,可采用基于


X2


接口的切换。



基于


S1


接口的切换



触发事件 :


A3


事件(同频切换)


< p>
A5


事件(异频切换)



当两个


eNodeB


之间不存在


X2< /p>


接口,



X2


接 口不可用时,


UE


从当前所驻留的


服务 小区切换到另一


eNodeB


时,可采用基于

< br>S1


接口的切换。



1.1.1



LTE

< br>到


3G


的切换



实现


LTE



3G

< p>
的切换首先需要满足几个前提:



1.



网络侧,


LTE


系统和


3G


系统均支持


LTE



3G


的< /p>


PS


切换



2.



UE


侧 ,


UE


需要支持


LTE



3G



PS


切换,


UE



Feature


Group


Indicator


bit



8



bit



22


数值必须为


1





LTE



3 G


切换的流程概述:



1.



LTE


基站如果收到


UE


上报的


A2


测量报告,发现


LTE


的覆盖较差。

< p>


2.



LTE


基站通过


RRC


重配置消息对

< br>UE


配置


B2


事件的测量的相关 参数。



3.



LTE


基站收到


B2


事件的测量报告 后,


通过


MobilityFromEutranComman d




UE


发 起到


3G


的切换。



4.



LTE


基站收到


UE


上发的


Mobility ToUtranComplete


,切换成功。



主要的


LTE RRC


空口信令:



?



UE


上报


B2


测量报告:


Measuremen t Report


?



UE



LTE


小区收到往


3 G


切换命令:


MobilityFromEutranComm and


?



UE


LTE


小区反馈到


3G


切换成功:


MobilityToUtranComplete




实用文档



具体的切换信令流程如下:



1


.切换准备信令流程(


3GPP 23.401






UE



Source



eNodeB



Target RNC



Source MME



Target



Target SGSN



Serving GW



Serving GW



PDN GW



HSS



Uplink and Downlink


User Plane PDUs






1. Handover Initiation





2.


H



andover


Required





3. Forward Relocation Request



4. Create Session Request



4a. Create Session Response



5. Relocation


Request





5a. Relocation



Request Acknowledge



6. Create Indirect Data Forwarding Tunnel Request



6a. Create Indirect Data Forwarding Tunnel Response





7. Forward Relocation Response




reate Indirect Data Forwarding Tunnel Request



8


.




C



reate Indirect Data Forwarding Tunnel Response



8


a



.


C



2


.切换执行信令流程(


3GPP 23.401







实用文档




UE



Source



eNodeB



Target RNC



Source MME



Target



Target SGSN



Serving GW



Serving GW



PDN GW



HSS



Uplink and Downlink User Plane PDUs



1. Handover Command



2. HO from E-UTRAN Command



-






4. UTRAN Iu Access Procedures


4a. Handover to UTRAN Complete



Sending of


uplink data


possible



Downlink User Plane PDUs



If Direct Forwarding applies



Via Target SGSN in case Direct Tunnel is not used



5. Relocation Complete



6. Forward Relocation Complete



6a. Forward Relocation Complete Acknowledge



7. Modify Bearer Request



If Indirect Forwarding applies.



For Serving GW relocation Steps 7, 8 and 9,


and the following User Plane path, will be


handled by Target Serving GW


(A)



8. Modify Bearer Request



8a. Modify Bearer Response



9. Modify Bearer Response



Uplink and Downlink User Plane PDUs (Via Target SGSN if Direct Tunnel is not used)



10. Routeing Area Update procedure


11. Delete Session Request



11b. Release Resources



11a. Delete Session Response



(B)



12. Delete Indirect Data Forwarding Tunnel




1.1.2



LTE



2G


的切换



LTE



2G


的具体切换信令流程:



1.



切换准备信令流程(


3GPP 23.401






实用文档





UE



Source



eNodeB



Target



BSS



Source MME



Target SGSN



Target



Serving GW



Serving GW



PDN GW



HSS



Uplink and Downlink



User Plane



PDUs



1. Handover Initiation



2. Handover Required



3. Forward Relocation Request



4. Create Session Request



4a. Create Session Response



5. PS Handover Request



5a. PS Handover Request Acknowledge



6. Create Indirect Data Forwarding Tunnel Request



6a. Create Indirect Data Forwarding Tunnel Response



7. Forward Relocation Response



8. Create Indirect Data Forwarding Tunnel Request



8a. Create Indirect Data Forwarding Tunnel Response




2.



切换执行信令流程(


3GPP 23.401






实用文档




UE



Source



eNodeB



Target BSS



Source MME



Target



Target SGSN



Serving GW



Serving GW



Uplink and Downlink User Plane PDUs



PDN



GW



HSS



1. Handover Command



2. HO from E-UTRAN Command



4. GERAN A/Gb Access Procedures



5. XID Response



Downlink User Plane PDUs



Sending of


uplink data


possible



Only if ”Direct Forwarding”


applies



Only if ”Indirect Forwarding” applies



6. PS Handover Complete



7. XID Response



8. Forward Relocation Complete Notification



8a. Forward Relocation Complete Acknowledge



9. Modify Bearer Request



For Serving GW relocation Steps 9, 10 and 11,


and the following User Plane path, will be


handled by Target Serving GW



12. XID Negotiation for LLC ADM



12a. SABM UA exchange



re-establishment and XID negotiation for LLC ABM)



Uplink and Downlink User Plane PDUs



13. Routeing Area Update procedure


14. Delete Session Request



14b. Release Resource



(B)



14a. Delete Session Response



(A)



10. Modify Bearer Request



10a. Modify Bearer Response



11. Modify Bearer Response




1.1.3



3G


LTE


的切换



3G



LTE


的具体切换信令 流程:



1.



切换准备信令流程(


3GPP 23.401






实用文档





UE



Source



RNC



Target



eNodeB



Target



Serving GW



PDN



GW



Source SGSN



Target MME



Serving GW



HSS



Uplink and Downlink



User Plane PDUs (via Source SGSN



in case Direct Tunnel



is



n


ot used)





1. Handover Initiation



2. Relocation Required



3. Forward Relocation Request



4. Create Session Request



4a. Create Session Response



5. Handover



Request





5a. Handover Request Acknowledge



6



.




C


reate



Indirect Data Forwarding Tunnel Request





6



a



.




C


reate



Indirect Data Forwarding Tunnel Response





7



.


Forward Relocation Response



.




C


reate



Indirect Data Forwarding Tunnel Request


8






8a.



Create



Indirect Data Forwarding Tunnel Response






2.



切换执行信令流程(


3GPP 23.401







实用文档




UE



Source



RNC



Target



eNodeB



Source SGSN



Target MME



Target



Serving GW



Serving GW



PDN



GW



HSS



Uplink and Downlink User Plane PDUs (via Source SGSN if Direct Tunnel is not used)



1. Relocation Command



2. HO from UTRAN Command



4. E-UTRAN Access Procedures



5. HO to E-UTRAN Complete





Sending of


uplink data


possible


Downlink Payload User Plane PDUs (via Source SGSN if Direct Tunnel is not used)



If Direct Forwarding applies



Via Source SGSN in case Direct Tunnel is not used



If Indirect Forwarding applies



6. Handover Notify



7. Forward Relocation Complete Notification



7a. Forward Relocation Complete Acknowledge



8. Modify Bearer Request



For Serving GW relocation Steps 8, 9 and 10,


and the following User Plane path, will be


handled by Target Serving GW



(A)





10. Modify Bearer Response



9. Modify Bearer Request



9a. Modify Bearer Response



Uplink and Downlink User Plane PDUs



11. Tracking Area Update procedure


12. Delete Session Request



12b. Iu Release Procedure



(B)



12a. Delete Session Response



13. Delete Bearer




1.1.4



2G


LTE


的切换



2G



LTE


的具体切换信令 流程:



1.



切换准备信令流程(


3GPP 23.401






实用文档





UE



Source



BSS



Target



eNodeB



Source



SGSN



Target MME





Target



Serving GW



Serving GW



PDN GW



HSS



Uplink and Downlink


User Plane



PDUs





1. Handover Initiation



2. PS Handover Required



3. Forward Relocation Request



4. Create Session Request





4a. Create Session Response



5. Handover Request





5a. handover Request Acknowledge




6. Create Indirect Data Forwarding Tunnel Request





6a. Create Indirect Data Forwarding Tunnel Response





7. Forward Relocation Response



8. Create Indirect Data Forwarding Tunnel Request





8a. Create Indirect Data Forwarding Tunnel Response






2.



切换执行信令流程(


3GPP 23.401







实用文档




UE



Source



BSS



Target



eNodeB



Source SGSN



Target MME



Target



Serving GW



Serving GW



PDN



GW



HSS



Uplink and Downlink User Plane PDUs



Only if 'Direct Forwarding' applies



Only if 'Indirect Forwarding' applies



1. PS HO Required Acknowledge



2. PS Handover Command



4. E-UTRAN Access Procedures



5. HO to E-UTRAN Complete



6. Handover Notify



Sending of


uplink data


7. Forward Relocation Complete Notification



possible



7a. Forward Relocation Complete Acknowledge



8



.


Modify Bearer Request



9. Modify Bearer Request



For Serving GW relocation Steps 8, 9 and 10, and


the following User Plane path, will be handled by


Target Serving GW



(A)



9a. Modify Bearer Response



10. Modify Bearer Response



Uplink and Downlink User Plane PDUs



11. BSS Packet Flow Delete Procedure



12. Tracking Area Update procedure


13. Delete Session Request



13a. Delete Session Response



14. Delete Indirect Data Forwarding Tunnel Request



14a. Delete Indirect Data Forwarding Tunnel Response





2



LTE


切换问题优化方法及流程



2.1



LTE


主要切换问题



2.1.1



邻区配置



邻区配置不合理案例:



问题描述:< /p>


通过统计观察到到小区


70736-4


的 切换成功率为


0%



而到


70272-2


的切换尝试次数为


0






实用文档




问题分析:经检查配置发现


70736-4



70272-2


这两个小区配置 了相同的


PCI


,而且正确的目标切换小区应该是


70272-2





问题解决:


通过删除


70736-4


的邻区关系后,



70272-2

< p>
的切换成功率恢复到


100%


< br>


2.1.2



参数设置



参数设置不合理案例:



问题描述:< /p>


通过观察基站侧统计发现有很多切换准备成功率为


0%

< p>
的邻区关系,


共同点是目标小区都属于同一个基站


(


基站


ID 4506-70483)




问题分析 :通过分析发现该基站


(


基站


ID 4 506-70483)


计数器


pmHoPrepRejInLi cMob


的数值很高,



计数器


pmHoPrepRejInLicMob


解释:统计由于目标基站缺 少切换相关的


license


而导致切换失败的次数。



问题解决:在激活目标基站的


license


之后,切换成功率恢复


100%










实用文档




2.1.3



无线环境引起的切换异常



案例介绍:



问题描述:路测中武昌路 段切换序列混乱,而且切换成功率较低。



< br>问题分析:


通过测试


log


分析 发现武昌路(红圈


1,2,3


)主要占用


SN


黄海饭店


2


< br>区(


PCI_238




SN


黄海饭店


2


小区 (


PCI_238


)天线挂高


70m,


越区覆盖严重,



问题解决:通过调整


SN


黄海饭店


2


小区(


PCI_238


)机械下倾角下压到

< br>10


度,控制


越区减小对其他小区干扰。


优化后武昌路主要占用世纪之星


3


小区信号(


PCI74



(下图红


框所示)


,信噪比改善,越区覆盖消除,切换恢复正常。





实用文档




2.2



LTE


切换问题优化流程



LTE


切换异常主要有以下几个现象:



1.



UE


向 源小区发送测量报告后没有收到切换命令



2.



UE


在 源区收到切换命令,在目标邻小区发送随机接入(


MSG1


)但 是未收到


随机接入响应


(MSG2)




3.



小区之间乒乓切换。



4.



小区之间切换序列混乱。



5.



切换过程中数据中断



针对这些切换异 常,应该从参数配置,邻区配置,基站传输,硬件告警,上下


行干扰等几个方面入手分析 问题。



切换问题分析流程:




其中参数合理性检查主要包括以下等几个方面:




-


-


-


-


-


-


-


-



本文更新与2021-02-08 09:52,由作者提供,不代表本网站立场,转载请注明出处:https://www.bjmy2z.cn/gaokao/613768.html

LTE切换优化专题-全参数功能和优化思路的相关文章