Thursday, 3 October 2013

CQI/PMI and RI on same subframe, SRS and PUCCH format 1/1a/1b 2/2a/2b on same subframe, SR and CQI/PMI on same subframe

If SRS and PUCCH format 2/2a/2b messages coincide in same subframe, UE shall not transmit SRS.
If SRS and PUCCH format 1/1a/1b (ACK/NACK and/or +SR) coincide in same subframe, UE shall transmit SRS iff simultaneousSRSACKNACK is true. 
If SRS and PUSCH RARG (Random Access Response Grant) coincide in same subframe SRS will be dropped.
If SRS and retransmission of same transport block (as a part of contention based Random access procedure),  coincide in the same subframe SRS will be dropped.
If SR and CQI/PMI/RI coincide in same sub-frame, CQI/PMI/RI will be dropped only if UE send SR (which is triggered by BSR) otherwise CQI/PMI/RI will be reported by UE on the same subframe.

If CQI/PMI and RI is configured on same subframe and coincide, MAC will schedule RI on that subframe   and hence UE will report RI on that subframe instead of CQI/PMI (One possible reason could be Periodicity of RI is always greater than equal to CQI/PMI. Which means eNB will have RI input less frequent than CQI/PMI input from UE, hence priority is given to RI).
(Example: Configure the higher layer parameter cqipmiconfigindex and riconfigindex in a way such that CQI/PMI and RI coincide on same subframe and verify the reporting using UE logs as well as FAPI interface . cqipmiconfigindex=17 and riconfigindex=483 could be one valid configuration to simulate this scenario,  according to Table 7.2.2-1A and Table 7.2.2-1B of 36.213).

Please share if you find this is useful information.
Questions are welcome.

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