Patent ID: 8559381

Claim:
A method comprising: using a predetermined parameter to determine by an apparatus a ratio of uplink radio resources to downlink radio resources; mapping an uplink radio resource to a unique one of the downlink radio resources dependent at least in part on the ratio, wherein the uplink radio resource is a resource over which the apparatus sends its transmission and the unique one of the downlink radio resources is a resource for transmitting a reply to the transmission sent over the uplink radio resource, and wherein mapping the uplink radio resource to a unique one of the downlink radio resources comprises determining an index of a downlink physical hybrid automatic repeat request indicator channel based at least in part on a physical resource block index of the transmission sent over the uplink radio resource and on the ratio; and receiving on the mapped unique one of the downlink radio resources a reply to an uplink transmission on the uplink radio resource, wherein the reply informs whether or not the uplink transmission on the uplink radio resource was successfully received.