Patent ID: 9706569
Date: 2017-07-11
CPC Classifications: H04L,H04W

Claim:
1. A communication apparatus comprising: a transmitter which, in operation, transmits, to a terminal, a control channel including a downlink assignment information indicating a resource for downlink data, the downlink data being allocated on a cell, and transmits, to the terminal, the downlink data; a receiver which, in operation, receives a response signal to the downlink data, the response signal being transmitted from the terminal, wherein: when a plurality of response signals to a plurality of downlink data on a plurality of cells are transmitted with channel selection and the downlink assignment information for a primary cell is included in a first control channel that is transmitted on a Control Channel Element (CCE) of a Physical Downlink Control Channel (PDCCH) region, the plurality of response signals are transmitted using one of a plurality of resources including a first resource determined by a first method according to which the first resource is determined from an index of the CCE of the PDCCH region; and when the plurality of response signals to the plurality of downlink data on the plurality of cells are transmitted with channel selection and the downlink assignment information for the primary cell is included in a second control channel that is different from the first control channel, the plurality of response signals are transmitted using one of a plurality of resources including a second resource determined by a second method that is different from the first method.