LAC Update only in Idle mode...but why ??

[dheerajdabarh]

Hi,

We haev LAC update only in Idle mode (in GSM/3G).
Why LAC update is only applicable in idle mode, why can't we may have LAC update in connected mode.

Regards
Dheeraj

[JCarlos21]

Hi dheerajdabarh,

Location Area Update is a procedure that is done to let the Network know in which area the UE is located.

When the UE is in Connected Mode, the Network already knows where the UE is located because it has dedicated channels attached to it through a Cell.

I hope this clear your doubt.

Best regards,

Hi,

We haev LAC update only in Idle mode (in GSM/3G).
Why LAC update is only applicable in idle mode, why can't we may have LAC update in connected mode.

Regards
Dheeraj

[Amr Harby]

Hi dheerajdabarh,

Location Area Update is a procedure that is done to let the Network know in which area the UE is located.

When the UE is in Connected Mode, the Network already knows where the UE is located because it has dedicated channels attached to it through a Cell.

I hope this clear your doubt.

Best regards,

I agree ... and to confirm that's why mobile is paged on dedicated mode using page type 2....while on idle mode udjng page type 1

[firstmaxim]

When the mobile is in connected mode, it is RRC protocols between UE and RNC/BSC that is important, because this is what orchestrates the handover between cells. LA update is a mobility management function which requires the involvement of MM protocols between UE and VLR. Since, tracking the UE in the network is an MM function, this aspect is not needed when there is already an RRC connection. The UE will do a LA update in the new LA once the call is completed.