Does SRB2 used only for NAS message ?

Question

As we know Per Resource Blocks (RB) SINR from UE report. I know that an UE reports all the RBs SINR as quick as possible (maybe each subframe period, that is 1 ms). I’m thinking of the Higher Layer-configured subband CQI report since it’s the most capable of inspecting the RBs status as I saw in 3GPP 36.213 Table 7.2.1-1. I’m interested in FDD; unfortunately the least “RB contiguous number” is 4 as in Table 7.2.1-3. Do we have a better method capable to inspect each RB?

Answer 1

Even I was aware about that SRB2 is used for only NAS messages. But I checked 3GPP RRC spec 36.331 release 10.

"SRB2 is for RRC messages which include logged measurement information as well as for NAS messages, all using DCCH logical channel. "

Can someone please tell me what is logged measurement information ? what is the use of this.

Answer 2

SRB0 –
> This is cell specific.
> Goes through CCCH channel.
> Only RRC message can go through it.

SRB1 -
> This is UE specific.
> Goes through DCCH
> It comes in action after RRC Connection set up.
> we can send RRC message and piggybacked NAS message.

SRB2 –
> This is UE specific.
> Priority is less than SRB1
> Goes through DCCH logical channel.
> It comes in action after RRC security is established.
> NAS messages goes over it but we can send also send RRC Message like
 (Logged measurement information ) over it.
> But It do not include any RRC protocol control information while sending RRC message.

For Full explanation u can refer
http://www.ltewirelesstech.com/2013/09/radio-bearers-in-lte.html