Patent ID: 9191180
Filing Date: 2015-11-17
Classification: H04L,H04W

Abstract:
1. A method of performing, by a user equipment to which a plurality of serving cells based on Time Division Duplex (TDD) has been allocated, a hybrid automatic repeat request (HARQ), the method comprising: receiving an uplink (UL) grant for a first subframe of a second serving cell through a first serving cell; transmitting UL data in the first subframe of the second serving cell based on the UL grant; and performing a non-adaptive retransmission for the UL data in a second subframe of the second serving cell if a not-acknowledgement (NACK) for the UL data is received through a physical HARQ indicator channel (PHICH) in a subframe i of the first serving cell, wherein the first serving cell and the second serving cell use different uplink-downlink (UL-DL) configurations, and each of the UL-DL configurations is information on which each subframe within a TDD frame is configured as an UL subframe, a DL subframe or a special subframe, and wherein if a PHICH resource corresponding to the UL data is not present in the subframe i, the non-adaptive retransmission is not allowed in the second subframe of the second serving cell.