Tuesday, February 23, 2010

Combined Tracking Area Update

Within a combined tracking area updating procedure the messages TRACKING AREA UPDATE ACCEPT and TRACKING AREA UPDATE COMPLETE carry information for the tracking area updating and the location area updating.

The UE operating in CS/PS mode 1 or CS/PS mode 2, in state EMM-REGISTERED, shall initiate the combined tracking area updating procedure:

a) when the UE that is attached for both EPS and non-EPS services detects entering a tracking area that is not in the list of tracking areas that the UE previously registered in the MME;

b) when the UE that is attached for EPS services wants to perform an attach for non-EPS services. In this case the EPS update type IE shall be set to "combined TA/LA updating with IMSI attach";

c) when the UE performs an intersystem change from A/Gb mode to S1 mode and the EPS services were previously suspended in A/Gb mode;

d) when the UE performs an intersystem change from A/Gb or Iu mode to S1 mode and the UE previously performed a location area update procedure or a combined routing area update procedure in A/Gb or Iu mode, in order to re-establish the SGs association. In this case the EPS update type IE shall be set to "combined TA/LA updating with IMSI attach";

e) when the UE enters EMM-REGISTERED.NORMAL-SERVICE and the UE's TIN indicates "P-TMSI";

f) when the UE receives an indication from the lower layers that the RRC connection was released with cause "load balancing TAU required";

g) when the UE deactivated EPS bearer context(s) locally while in EMM-REGISTERED.NO-CELL-AVAILABLE, and then returns to EMM-REGISTERED.NORMAL-SERVICE;

h) when the UE changes the UE network capability information or the MS network capability information or both;

i) when the UE changes the UE specific DRX parameter;

j) when the UE receives an indication of "RRC Connection failure" from the lower layers and has no user uplink data pending;

k) when due to manual CSG selection the UE has selected a CSG cell whose CSG identity is not included in the UE's Allowed CSG list;

l) when the UE reselects an E-UTRAN cell while it was in GPRS READY state or PMM-CONNECTED mode;

m) when the UE supports SRVCC to GERAN or UTRAN and changes the mobile station classmark 2 or the supported codecs, or the UE supports SRVCC to GERAN and changes the mobile station classmark 3; or

n) when the UE changes the radio capability of at least one of the following radio access technologies: GERAN, UTRAN or cdma2000®.

For case n, the UE shall include a UE radio capability information update needed IE in the TRACKING AREA UPDATE REQUEST message.

2 comments:

Jeff said...

Hi Vikram
Thanks for the infomative posts on LTE. I have a question related to TAU.

24.301 5.3.3 States that a UE in CS/PS Mode 1 or 2 must perform a combined TAU with type set to TA/LA and maybe TA/LA with IMSI attach. But I cannot find any reference to the subsequent actions in the network. For example with type field set to TA/LA does an MME have some mechanism whereby it can trigger a location update in the CS domain. If so where in the standards is this defined.

Thanks again.Jeff

Gyanendra Singh said...

Yes, MME would do update location MSC with corresponding type.