Terminal, base station, communications system, and communication method for allocating hybrid automatic repeat request acknowledge resource using control channel

A base station apparatus that is configured to and/or programmed to communicate with a terminal apparatus, the base station apparatus comprising:

• a physical control information notifier configured to and/or programmed to transmit an Enhanced Physical Downlink Control Channel (EPDCCH), and
• a response information receiver configured to and/or programmed to receive Hybrid Automatic Repeat request (HARQ) response information using a first Physical Uplink Control Channel (PUCCH) resource and a second PUCCH resource for a Physical Downlink Shared Channel (PDSCH) transmission associated with the EPDCCH, wherein
• the first PUCCH resource is determined on the basis of at least a lowest element index used to construct the EPDCCH and a first value which is a PUCCH resource offset and is determined, within a plurality of values, from a field in downlink control information of the EPDCCH;
• and
• an index of the second PUCCH resource is an index of the first PUCCH resource plus one.

A communication method used by a terminal apparatus that is configured to and/or programmed to communicate with a base station apparatus, the communication method comprising:

• detecting an Enhanced Physical Downlink Control Channel (EPDCCH), and transmitting Hybrid Automatic Repeat request (HARQ) response information using a first Physical Uplink Control Channel (PUCCH) resource and a second PUCCH resource for a Physical Downlink Shared Channel (PDSCH) transmission indicated by a detection of the EPDCCH, wherein
• the first PUCCH resource is determined on the basis of at least a lowest element index used to construct the EPDCCH and a first value which is a PUCCH resource offset and is determined, within a plurality of values, from a field in downlink control information of the EPDCCH;
• and
• an index of the second PUCCH resource is an index of the first PUCCH resource plus one.

A communication method used by a base station apparatus that is configured to and/or programmed to communicate with a terminal apparatus, the communication method comprising:

• transmitting an Enhanced Physical Downlink Control Channel (EPDCCH), and
• receiving Hybrid Automatic Repeat request (HARQ) response information using a first Physical Uplink Control Channel (PUCCH) resource and a second PUCCH resource for a Physical Downlink Shared Channel (PDSCH) transmission associated with the EPDCCH, wherein
• the first PUCCH resource is determined on the basis of at least a lowest element index used to construct the EPDCCH and a first value which is a PUCCH resource offset and is determined, within a plurality of values, from a field in downlink control information of the EPDCCH;
• and
• an index of the second PUCCH resource is an index of the first PUCCH resource plus one.