2012年9月17日 星期一
PLMN Priority
PLMN Priority :
⑴RPLMN 曾經註冊過的or上次所使用的
⑵EPLMN 與當前所選擇的PLMN等同地位的
⑶HPLMN USIM卡上的IMSI中包含的MCC和MNC與HPLMN上的MCC和MNC是一致的，一個UE只有一個HPLMN。
⑷EHPLMN 與當前所選擇的PLMN處於同等地位的HPLMN
⑸UPLMN 存在USIM卡上的一個與PLMN選擇有關的參數，User Controlled PLMN
⑹OPLMN 存在USIM卡上的一個與PLMN選擇有關的參數，Operator Controlled PLMN
⑺其他的PLMN 如:VPLMN,APLMN...
LTE Non Access Stratum (NAS) Overview
1.
Protocols in LTE-NAS
EPS
Mobility Management (EMM)
Supports mobility
functions in the UE
EPS
Session Management (ESM)
Supports
establishment and maintenance of IP connectivity between the UE
and the PDN
gateway.
2.
Integrity Protection (IP) and
Ciphering of NAS signaling messages
3.
Only support PS domain
4.
(used to tunnel CS SMS when
combined attached for EPS and non-EPS) or Fallback (CSFB) to other systems
(UMTS, GSM or 1X)
5.
Operating modes:
-
PS mode: LTE only
-
CS/PS mode 1: Non-EPS>LTE
-
CS/PS mode 2: LTE>Non-EPS
6.
GUTI(Globally Unique Temporary
Identifier)=> <GUMMEI><M-TMSI>
7.
GUMMEI=><MCC><MNC>
8.
<MME Identifier>=>
<MME group ID><MME code>
9.
EPS update status:
-
EU1=>”Updated”
-
EU2=>”Not Updated”
-
EU3=>”Roaming Not Allowed”
10.
EPLMN list – EMM, GMM, and MM
shall use the same list.
11.
Timer: T34XX are different with
UMTS.
12.
EMM procedures:
-
EMM Common procedures:
initiated by MME while a NAS signaling connection exists.
-
EMM Specific procedures:
attach, detach, Tracing area procedure (only one at time)
-
EMM Connection Management
procedures: establish a secure connection with network or request for sending
data
13.
EMM Common Procedures:
-
GUTI Reallocation(MME->UE)
-
Authentication(MME->UE)
-
(Security Mode Control)SMC (MME->UE)
-
Identification (MME->UE)
-
EMM Information(MME->UE)
14.
EMM Specific Procedures:
-
Attach (UE->MME) for resisted,
T3410
-
Detach(UE<->MME) T3421 (UE
side), T3422(MME side)
-
TAU (UE->MME) T3430
15.
Connection Management Procedures:
-
Service Request(UE->MME)
T3417, T3417 Extend
-
Paging (MME->UE)
-
Transport of NAS Message (UE<->MME)
Carry CS SMS message
16.
EMM-NAS security:
-Integrity Protection (IP)
-Ciphering
17.
NAS Security Parameters: NAS
COUNT, NAS Sequence Number (SN), Security Terminology
18.
EPS Session Management(ESM): {Procedure
Transaction ID(PTI), EPS Bearer ID, EPS Bearer, Default EPS bearer, ESM and SM
coordination}
-
Procedure related to EPS bearer
context
n Default EPS Bearer Context Activation(MME->UE) T3485
n Dedicated EPS Bearer Context Activation(MME->UE) T3485
n EPS Bearer Context Modification (MME->UE) T3486
n EPS Bearer Context Deactivation (MME->UE) T3495
-
Transaction related procedures
n PDN Connectivity (UE->MME) T3482
n PDN Disconnect (UE->MME) T3492
n Bearer Resource Allocation (UE->MME) T3480
n Bearer Resource Modification (UE->MME) T3481
n ESM Information Request (Network Initiated in response to PDN Connectivity
Request) (MME->UE) T3489
2012年9月5日 星期三
PLMN Selection Process
PLMN selection 為UE保持連線的重要技術之一
2個PLMN是來自不同的operator, 並且在同一個區域內可能會有多個PLMN
PLMN selection發生的場景可能有下列三種:
1. UE開機或 重回到有PLMN coverage area
2. UE 自行要求 PLMN re-selection
3. UE 在 漫遊其間,週期性的搜尋HPLMN
PLMN selection可分為Auto mode(default )/ manual mode
正常步驟:
UE開機=>選擇best PLMN=> select cell / registration => EPS process
當lose cell coverage :
選擇 old PLMN list / select new cell => 假如new cell 不屬於相同的registration area ,則進入TA process
當lose PLMN coverage:
select new PLMN / show all available PLMN on the list
========================================================================
當UE在idle 時, cell re-selection是為了保證UE可以取得best cell,以便讓UE可以keep service 並 change to the control channel
當UE處於idel :
renew location可以分為兩種(normal location renew & periodic location renew)
目的是讓network can trace UE mobility
========================================================================
MCC=> Mobile country code (3 bits)
MNC=> Mobile network code (2~3 bits)
組合成每個UE唯一的辨識碼
========================================================================
Auto mode下選擇的優先序:
RPLMN=> HPLMN=> USIM中UE 曾經control 的PLMN=> USIM中operator設定的PLMN=> other PLMNs (根據訊號的強弱選擇)
Manual mode下的優先續:
RPLMN=> selection by UE (所有可用的PLMNs)
訂閱：
文章 (Atom)