Base station apparatus, mobile station apparatus, method for mapping a response signal, and method for determining a response signal resource

A method in a mobile station apparatus comprising:

• receiving, from a base station, allocation information indicating one or a plurality of uplink resource blocks, the resource blocks being consecutive in a frequency domain;
• and indices of the plurality of consecutive resource blocks being respectively associated with a plurality of resources of downlink which are different in a frequency domain;
• making a determination with a processor, based on the allocation information, at least one of the resources of downlink, to which an ACK or NACK signal for uplink is mapped, from an index of the allocated resource block within the indices of the plurality of consecutive resource blocks, the ACK or NACK signaling being transmitted from the base station.

A method in a base station apparatus comprising:

• allocating, to a mobile station, one or a plurality of resource blocks of uplink, the resource blocks being consecutive in a frequency domain, and indices of the plurality of consecutive resource blocks being respectively associated with a plurality of resources of downlink which are different in the frequency domain;
• mapping with a processor an ACK or NACK signal for uplink data to at least one of the resources of downlink, the one of the resources being determined from an index of the allocated resource block within the indices of the plurality of consecutive resource blocks.