Patent ID: 9246620
Filing Date: 2016-01-26
CPC Classification: H04J,H04L,H04W

Claim Text:
1. A method of transmitting an ACK/NACK in a wireless communication system based on Time Division Duplex in which M, M=4, downlink subframes are associated with an uplink subframe, the method comprising: receiving, by a user equipment, at least one downlink transport block in the M downlink subframes for each of a plurality of serving cells from a base station; receiving, by the user equipment, zero or more downlink transport blocks in the M downlink subframes from a first serving cell; determining, by the user equipment, ACK/NACK states {HARQ-ACK(1),HARQ-ACK(2),HARQ-ACK(3), HARQ-ACK(4)} for the first serving cell; determining, by the user equipment, an ACK/NACK response based on the ACK/NACK states; and transmitting, by the user equipment, the ACK/NACK response in the uplink subframe, wherein each downlink transport block is received on each physical downlink shared channel (PDSCH) and a PDSCH is indicated by a downlink resource assignment in a downlink grant on a corresponding physical downlink control channel (PDCCH), and the downlink grant includes a downlink assignment index (DAI) which indicates an accumulative number of PDCCH with assigned PDSCH transmission, wherein the ACK/NACK states {HARQ-ACK(1),HARQ-ACK(2),HARQ-ACK(3), HARQ-ACK(4)} are determined among possible ACK/NACK states, the possible ACK/NACK states comprising at least six states of (A, A, A, N/D), (A, A, N/D, any), (A, D, D, D) , (A, A, A, A), (N/D, any, any, any) and (A, N/D, any, any) except for (A, D, D, D), where ‘A’ indicates ACK for a corresponding downlink transport block, ‘N’ indicates NACK for a corresponding downlink transport block, ‘D’ indicates no transmission (DTX) in a corresponding downlink subframe, and ‘any’ indicates any of ACK, NACK and DTX, and wherein HARQ-ACK(j), j=1,2,3,4, is ACK/NACK/DTX for a corresponding downlink transport block on PDSCH with a DAI value j in the corresponding PDCCH.