Method and apparatus for performing HARQ in a wireless communication system

摘要

The present invention provides a method and apparatus for performing hybrid automatic repeat request (HARQ) in a wireless communication system. A terminal transmits a plurality of code words on a physical uplink shared channel (PUSCH) and receives a plurality of acknowledgement/non-acknowledgement (ACK/NACK) signals, which indicates if each of the plurality of code words has been received, on each physical hybrid-ARQ indicator channel (PHICH) corresponding to the respective code words. A downlink resource for which each of the PHICHs is mapped is determined based on the smallest physical resource block (PRB) index (IPRB—RAlowest—index) among PRBs mapped by the PUSCH and on an uplink demodulation reference signal (DMRS) circular shift parameter (nDMRS), and those downlink resources for which PHICHs are mapped respectively do not overlap each other.

主权项

1. A method of determining, by a user equipment (UE), a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) resource in a wireless communication system, the method comprising:
determining a first PHICH resource and a second PHICH resource respectively corresponding to a first codeword and a second codeword, wherein the first PHICH resource is determined based on a lowest physical resource block (PRB) index IPRB—RAlowest—index among PRBs in a first slot to which a physical uplink shared channel (PUSCH) is mapped, and wherein the second PHICH resource is determined based on the lowest PRB index IPRB—RAlowest—index, and an offset β according to equation below:nPHICHgroup=((IPRB_RAlowest_index+β)+nDMRS)⁢mod⁢⁢NPHICHgroup+IPHICH⁢NPHICHgroup⁢⁢nPHICHseq=(⌊IPRB_RAlowest_index+β)/NPHICHgroup⌋+nDMRS)⁢mod⁢⁢2⁢NSFPHICH, where nPHICHgroup is an index of a PHICH group, nPHICHseq is an orthogonal sequence index in the PHICH group, IPRB—RAlowest—index is the lowest PRB index among PRBs in a first slot to which the PUSCH is mapped, β is the offset, nDMRS is a cyclic shift field for a demodulation reference signal (DMRS), NPHICHgroup is the number of PHICH groups, IPHICH is a value 0 or 1, and NSFPHICH is a size of a spreading factor (SF).