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LTE - UE States (Attach)

LTE - UE States (Attach) [Under LTE]
» E-UTRA and E-UTRAN overall description - 36.300, Rel 8 «
» E-UTRAN access - 23.401, Rel 8 «
» NAS - 24.301, Rel 8 «
» RRC - 36.331, Rel 8 «

In next few articles, we will look at UE state at various stages from NAS/AS point of view. We will consider initial attach, tracking area update, service request, and detach scenarios.

Overall NAS/AS states reference: 23.401:4.6, 24.301:5.1.3, 36.300:A.2, 36.331:4.2.1


Radio Access steps Bearer contexts inactive
EMM_NULL
RRC_NULL
RF scanning, Cell search
EMM_DEREGISTERED
(PLMN SEARCH)

RRC_IDLE
Radio Access steps +COPS=0;+CGATT=1 PLMN, Cell selected, DL synch
UL synch/Random access
RRC Connection request →
EMM_REGISTERED_INITIATED
RRC_IDLE
RRC Connection Setup ←
RRC Connection Setup complete →
[Attach Request/PDN Connectivity request]
EMM_REGISTERED_INITIATED
RRC_CONNECTED
Authentication request ←
Authentication response →
NAS Security mode command ←
NAS Security mode complete →
EMM_REGISTERED_INITIATED
RRC_CONNECTED
AS Security mode command ←
RRC Connection Reconfiguration ←
[Attach Accept/Activate Default Bearer request]
AS Security mode complete →
RRC Connection Reconfiguration complete →
EMM_REGISTERED_INITIATED
RRC_CONNECTED
(DRBs established)
Bearer contexts active
EMM_REGISTERED
(NORMAL SERVICE)

RRC_CONNECTED
Attach Complete/Activate Default Bearer Accept →


Specifications use couple of more variables, EMM mode and ECM state, both of these are same as RRC state (in case of UE). That is EMM_IDLE/ECM_IDLE ⇒ RRC_IDLE and EMM_CONNECTED/ECM_CONNECTED ⇒ RRC_CONNECTED.

Copyright © Samir Amberkar 2010-12§

LTE - end-to-end data flow eNB « LTE Index » LTE - UE States (TAU)