How SMS is sent in WCDMA?

[khurrambilal01]

Hi experts,

How SMS is sent in 3G? On which channel?
How i receive SMS while i am on CS or PS RAB ?
Any document ? Because i didn't find some useful link/document for understanding.
Thanks for the support!

[Nyquist]

Hi.
It is transferred over the SDCCH. However, if the UE is in connected mode, it will use the FACCH instead of SDCCH.
You can read more in 3GPP TS 23.040, Technical realization of the Short Message Service.

Regards

[bino]

Hi experts,

How SMS is sent in 3G? On which channel?
How i receive SMS while i am on CS or PS RAB ?
Any document ? Because i didn't find some useful link/document for understanding.
Thanks for the support!

Hi,

Check this thread.
http://www.finetopix.com/showthread.php?25601-SMS-flow-in-UMTS

[khurrambilal01]

Hi.
It is transferred over the SDCCH. However, if the UE is in connected mode, it will use the FACCH instead of SDCCH.
You can read more in 3GPP TS 23.040, Technical realization of the Short Message Service.

Regards

Thanks Nyquist; But my query was related to UMTS not GSM :)

[wolverine]

It is transferred using the SRB (Signalling Radio Bearer). The SRB can co-exist with DRB (data radio bearer) so you can receive SMS while having a CS RAB or PS RAB or both. Which channels are used depends on the RRC state the UE is in. If in CELL_DCH the SRB is mapped on the DCH, if in CELL_FACH then FACH/RACH.

[ritgail]

Simple and straight:

RACH/FACH in case on only SMS.

otherwise as said below.

[ltecity]

What is way incase of Multi RAB?