LTE Concept and Applications

KMIMO is a parameter which is being used in bit collection , selection and transmission of downlink data (specifically to calculate size of a partition which is used for storing a transport block). It  is equal to  2, if UE is configured to receive PDSCH transmissions based on transmission mode 3, 4 or 8, as defined in section 7.1 of 3GPP 36.213, 1 otherwise.Also in other words , it represents maximum number of transport blocks that may be transmitted to the UE in a single TTI (Transmission Time Interval or 1ms or 1 subframe time). Questions are welcome.

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 wi...

SR (Scheduling Request) is a request of scheduling radio resource for uplink transmission by the UE to the eNB. UE send SR on PUCCH when regular BSR (Buffer status report) is triggered and UE does not have radio resource to transmit this BSR to eNB.  To send this SR, UE must be configured with SR periodicity. If PUCCH resource is not configured for SR, UE start RA (Random Access) procedure. Since PUCCH resource is limited, SR periodicity should not be very less (short periodicity leads to fast resource allocation). If we fix short periodicity for SR, UE may not utilize the PUCCH for SR transmission allocated each time (UE may not have data to transmit in uplink always).   There must be a tradeoff between PUCCH load and SR periodicity.  UE always keep track of SR transmission on PUCCH. After reaching the maximum number of SR transmission (SR Max) and UE has not been allocated any radio resource for uplink transmission, it releases PUCCH resource for SR and s...