A user equipment which communicates with a base station apparatus in a Long Term Evolution, LTE, communication system, comprising: a reception unit configured to receive a physical downlink shared channel, PDSCH, or a control channel indicating semi-persistent scheduling, SPS, release on a serving cell; a processor configured to generate hybrid automatic repeat request - acknowledgement, HARQ-ACK, feedback bits for the PDSCH or the control channel; and a transmission unit configured to transmit the HARQ-ACK feedback bits, wherein the processor determines the HARQ-ACK feedback bits based on time division duplex, TDD, HARQ-ACK reporting procedure for different uplink/downlink, UL/DL, configurations, when the user equipment is configured with more than one serving cell, each serving cell of the more than one serving cell is a TDD cell, and at least two configured serving cells of the more than one serving cell have respective UL/DL configurations which are different from each other, when the user equipment is configured with more than one serving cell, a primary cell included in the more than one serving cell is a TDD cell, the serving cell included in the more than one serving cell is a frequency division duplex, FDD, cell, DL-reference UL/DL configuration of each of the primary cell and the serving cell is any one of {0,1,2,3,4,6}, and a physical uplink control channel, PUCCH, format 1b with channel selection is configured for a transmission of the HARQ-ACK feedback bits for the primary cell and the serving cell, the processor assumes that UL-reference UL/DL configuration for the serving cell is any one of {1, 2, 3, 4, 6} and determines, based on a) the UL-reference UL/DL configuration, which is any one of {1, 2, 3, 4, 6}, and b) the TDD HARQ-ACK reporting procedure, the HARQ-ACK feedback bits. a reception unit configured to receive a physical downlink shared channel, PDSCH, or a control channel indicating semi-persistent scheduling, SPS, release on a serving cell; a processor configured to generate hybrid automatic repeat request - acknowledgement, HARQ-ACK, feedback bits for the PDSCH or the control channel; and a transmission unit configured to transmit the HARQ-ACK feedback bits, wherein the processor determines the HARQ-ACK feedback bits based on time division duplex, TDD, HARQ-ACK reporting procedure for different uplink/downlink, UL/DL, configurations, when the user equipment is configured with more than one serving cell, each serving cell of the more than one serving cell is a TDD cell, and at least two configured serving cells of the more than one serving cell have respective UL/DL configurations which are different from each other, when the user equipment is configured with more than one serving cell, a primary cell included in the more than one serving cell is a TDD cell, the serving cell included in the more than one serving cell is a frequency division duplex, FDD, cell, DL-reference UL/DL configuration of each of the primary cell and the serving cell is any one of {0,1,2,3,4,6}, and a physical uplink control channel, PUCCH, format 1b with channel selection is configured for a transmission of the HARQ-ACK feedback bits for the primary cell and the serving cell, the processor assumes that UL-reference UL/DL configuration for the serving cell is any one of {1, 2, 3, 4, 6} and determines, based on a) the UL-reference UL/DL configuration, which is any one of {1, 2, 3, 4, 6}, and b) the TDD HARQ-ACK reporting procedure, the HARQ-ACK feedback bits.