Terminal device, base station device, and uplink response signal transmission method

A method performed by a terminal apparatus, the method comprising:

• determining a physical uplink control channel (PUCCH) resource based on a leading enhanced control channel element (eCCE) index (neCCE) of an enhanced physical downlink control channel (ePDCCH) received by the terminal apparatus and a first offset value indicated by an acknowledgement/negative-acknowledgement (Ack/Nack) Resource Indicator (ARI) out of a plurality of offset values, wherein the first offset value is a negative value and calculated using a formula that includes as a parameter a size of an ePDCCH search space set configured for the terminal apparatus, wherein the size of the ePDCCH search space set for a special subframe is smaller than the size of the ePDCCH search space set for a non-special subframe such that an absolute value of the first offset value calculated for a special subframe is smaller than an absolute value of the first offset value calculated for a non-special subframe;
• arranging a response signal on the determined PUCCH resource;
• and
• transmitting the response signal on the determined PUCCH resource.

An integrated circuit for controlling operation of a terminal apparatus, the integrated circuitry comprising:

• control circuitry, which, in operation,
• determines a physical uplink control channel (PUCCH) resource based on a leading enhanced control channel element (eCCE) index (neCCE) of an enhanced physical downlink control channel (ePDCCH) received by the terminal apparatus and a first offset value indicated by an acknowledgement/negative-acknowledgement (Ack/Nack) Resource Indicator (ARI) out of a plurality of first offset values, wherein the first offset value is a negative value and calculated using a formula that includes as a parameter a size of an ePDCCH search space set configured for the terminal apparatus, wherein the size of the ePDCCH search space set for a special subframe is smaller than the size of the ePDCCH search space set for a non-special subframe such that an absolute value of the first offset value calculated for a special subframe is smaller than an absolute value of the first offset value calculated for a non-special subframe, and
• arranges a response signal on the determined PUCCH resource;
• and
• transmission circuitry, which, in operation, controls transmission of the response signal on the determined PUCCH resource.