How the concatenation and segmentation works in Physical Downlink Shared Channel (PDSCH) processing?

Question

I'm a little confused about the description of RNTI values used for scrambling DL-SCH data in Section 7.1 of 36.213. My questions are the following,

a) From the Transmitter(eNB) perspective, how do we pick the right RNTI value for scrambling DL-SCH data as part of the PDSCH processing ?. To elaborate, Is the choice between C-RNTI, SI-RNTI, P-RNTI for c_init made based on Transmission Scheme ? How ?

b) What is the range ( in decimal values) corresponding to each of the above mentioned RNTI choices ?

Answer 1

Segmentation and concatenation in PDSCH is resulting from the fact that the maximum size of block that is encoded by turbo encoder is 6114 bits. However if the size of the data for the UE in a particular TTI is larger than 6114, the PHY layer performs segmentation into several codeblocks. Then, each of these codeblocks is separately encoded by turbo encoder. After encoding the PHY layer performs concatenation of all of these encoded codeblocks, to get a single transport block to be processed further on as a single.