Device and method for HARQ ACK/NACK bits transmission

A method in a wireless terminal, the method comprising:

• when a plurality of hybrid automatic repeat request (HARQ) ACK/NACK bits corresponding to a plurality of downlink component carriers (DL CCs) configured in the wireless terminal are transmitted on a single physical uplink control channel (PUCCH) on a single uplink component carrier (UL CC), changing, depending on the number of the plurality of DL CCs or the number of the plurality of HARQ ACK/NACK bits, a spreading rate to be applied to time-domain spreading of a plurality of modulation symbols generated from the plurality of HARQ ACK/NACK bits, wherein
• the changing includes selectively perform a plurality of time-domain spreading operations including first and second time-domain spreading operations to change the spreading rate, depending on the number of the plurality of DL CCs or the number of the plurality of HARQ ACK/NACK bits,
• the first time-domain spreading operation includes performing time-domain spreading on a single data block at a spreading rate of 2n (n is an integer) by using a first length-2n spreading code sequence, wherein the single data block is to be mapped to predetermined 2n single-carrier FDMA (SC-FDMA) symbols within a single slot in accordance with a PUCCH format used to transmit the plurality of HARQ ACK/NACK bits, and
• the second time-domain spreading operation includes preforming time-domain spreading on two data blocks at a spreading rate of n by using a second length-n spreading code sequence consisting of n elements of the first spreading code sequence and a third length-n spreading code sequence consisting of the remaining n elements of the first spreading code sequence, wherein the two data blocks is to be mapped to the predetermined 2n SC-FDMA symbols within the single slot in accordance with the PUCCH format.

A base station, comprising:

• a wireless transceiver configured to wirelessly communicate with a wireless terminal;
• and
• at least one processor coupled to the wireless transceiver, wherein
• the at least one processor is configured to receive, from the wireless terminal, a physical uplink control channel (PUCCH) transmitted in accordance with a PUCCH format, and
• the PUCCH format enables the wireless terminal, when a plurality of hybrid automatic repeat request (HARQ) ACK/NACK bits corresponding to a plurality of downlink component carriers (DL CCs) configured in the wireless terminal are transmitted on a single physical uplink control channel (PUCCH) on a single uplink component carrier (UL CC), to change a spreading rate to be applied to time-domain spreading of a plurality of modulation symbols generated from the plurality of HARQ ACK/NACK bits, depending on the number of the plurality of DL CCs or the number of the plurality of HARQ ACK/NACK bits, wherein
• the changing of the spreading rate includes selectively perform a plurality of time-domain spreading operations including first and second time-domain spreading operations to change the spreading rate, depending on the number of the plurality of DL CCs or the number of the plurality of HARQ ACK/NACK bits,
• the first time-domain spreading operation includes performing time-domain spreading on a single data block at a spreading rate of 2n (n is an integer) by using a first length-2n spreading code sequence, wherein the single data block is to be mapped to predetermined 2n single-carder FDMA (SC-FDMA) symbols within a single slot in accordance with a PUCCH format used to transmit the plurality of HARQ ACK/NACK bits, and
• the second time-domain spreading operation includes performing time-domain spreading on two data blocks at a spreading rate of n by using a second length-n spreading code sequence consisting of n elements of the first spreading code sequence and a third length-n spreading code sequence consisting of the remaining n elements of the first spreading code sequence, wherein the two data blocks is to be mapped to the predetermined 2n SC-FDMA symbols within the single slot in accordance with the PUCCH format.