How TB can be formed with Scheduling of 4 UEs Data in Particular TTI?

Question

Suppose 4 UEs selected to schedule in particular TTI ... first UE have PBCH data and second UE having RAR ... Third and fourth UEs have PDSCH data and UL grants ..... How TB of different UEs data in a single TTI can be foemed ... And how UE decode it?

Answer 1

Hi,

PDCH is not UE specific, it is not TB as well because MAC wont process anything with that data, what ever it recieve from upper layer it will forward it to PHY.

For RAR MAC will contruct an single TB, For the 3rd and 4th UE datat MAC will construct 2 different TB, Finally 3 TB will be given to PHY, and 5 DCI will be given to PHY(2 - UL GRANT, 2 -DL data assignment, 1 RAR DCI)..

Comments

Hi Jaganathan, In this case MAC gives 3 different TBs of 3 different UEs . so how PHY can process it..... can PHY transmit all these 3 TBs in the same TTI or not ?

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Yes, PHY can transmit all these TB in same TTI. However all TB will be mapped to different RB's , so there will be no problem

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For suppose if there have only 2 antennas supported how come PHY transfers 3 TBs?

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No, There is no mapping of TB and antenna. One DLSCH can send any number of TB based on DCI.
Antenna to TB mappping is UE poin of view. If 2 antenna is there then UE can recieve 2 TB max. same way all the UE can recieve 2 TB at a time.

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Hi jaganath, am bit confuse .... How DCI related with No of TBs. Can you please explain it ..

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except DCI 0 , all other DCI formats will have its corresponding TB. If you are giving DCI menas ENB have scheduled DL data for UE so Each DCI will have its corresponding TB

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can eNB schedule multiple DLSCH and DCI for single UE ??

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Hi,

No it is not possible for single UE, But this can happen,  An UE having DL data and SIB changes, then UE can read multiple DL-SCH and DCI in single SF