PDA

View Full Version : Question on BCCH Mapping on PDSCH



firstmaxim
2011-10-16, 01:31 PM
Hello,

I have a question on BCCH Mapping on PDSCH in LTE. The mapping table in LTE shows BCCH mapping as:

BCCH => BCH => PBCH
BCCH => DL-SCH => PDSCH

MIB is broadcast using the PBCH, while the SIBs are broadcast using the PDSCH. According to this logic, PDSCH is being broadcast in the downlink in the RRC idle mode, just like PBCH. Am I getting this correct? Can someone clarify/elucidate.

Regards

T_ADD
2011-10-17, 06:23 AM
Hi, to me since SI change is paged in both RRC_IDLE and RRC_CONNECTED modes, the PDSCH and PBCH will be broadcast in both the RRC_IDLE and RRC_CONNECTED modes.

firstmaxim
2011-10-17, 12:56 PM
Hi, to me since SI change is paged in both RRC_IDLE and RRC_CONNECTED modes, the PDSCH and PBCH will be broadcast in both the RRC_IDLE and RRC_CONNECTED modes.

It is understandable that BCCH mapped on PBCH is broadcast in the RRC_Idle state, but why would PDSCH and PBCH be broadcast in the RRC_Connected Mode?

T_ADD
2011-10-17, 02:31 PM
It is understandable that BCCH mapped on PBCH is broadcast in the RRC_Idle state, but why would PDSCH and PBCH be broadcast in the RRC_Connected Mode?

I'm thinking because the SI change is broadcast in both idle and active, then it would only make sense for them to be broadcast in both as well, right?

Is that so or am I missing the point? :)