QUALCOMM Incorporated
COMB ADAPTATION FOR INTERLACED FDM DMRS

Abstract:

Comb adaptation for interlaced frequency division multiplex (IFDM) demodulation reference signals (DMRS) is discussed. Transmission configuration for DMRS may be assigned to UEs with a coded combination of cyclic shift, OCC, and comb value. Some assigned combinations provide for a different comb value to be used for the different slots in the same subframe. Further aspects provide additional interference randomization through comb shifting, using inter-subframe hopping functions. Additionally, where retransmissions are present without uplink grant, the UE may select comb values for retransmissions based on the counter number for the retransmissions, which are different than the comb values used for the original DMRS transmissions.