Method of transmitting sounding reference signal
A method of transmitting a sounding reference signal (SRS) includes receiving SRS operation information including a sounding indicator, the sounding indicator indicating whether SRS transmission takes place at a subframe; generating the SRS according to the SRS operation information, and if the sounding indicator indicates occurrence of SRS transmission, transmitting the SRS at the subframe. Multiplexing can be achieved without collision between data and a sounding reference signal and single carrier characteristics required in uplink transmission can be preserved.
1. A method of transmitting a downlink subframe in a wireless communication system, the method performed by a base station (BS) and comprising:
transmitting a simultaneous transmission indicator to a user equipment (UE) that indicates whether a sounding reference signal (SRS) and a hybrid automatic retransmission request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK) are to be transmitted by the UE in a same subframe;
transmitting SRS operation information to the UE that indicates a periodicity of transmission of the SRS and a subframe offset to be used for the transmission of the SRS;
receiving the SRS, the HARQ ACK/NACK and a demodulation reference signal (DM-RS) from the UE when the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are to be transmitted in the same subframe, the DM-RS used by the BS to demodulate the HARQ ACKNACK in an SRS subframe; and
receiving the HARQ ACK/NACK and the DM-RS from the UE in the SRS subframe without the SRS when the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are not to be transmitted in the same subframe,
wherein the SRS is received in a last single carrier-frequency division multiple access (SC-FDMA) symbol of the SRS subframe, and
wherein the HARQ ACK/NACK and the DM-RS are received in remaining SC-FDMA symbols of the SRS subframe.
2. The method of claim 1 , wherein the SRS operation information facilitates determining the SRS subframe among a plurality of subframes.
3. The method of claim 1 , wherein, if the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are not to be transmitted in the same subframe, the DM-RS is received in three SC-FDMA symbols of each of a first slot and a second slot of the SRS subframe and the HARQ ACK/NACK is received in four SC-FDMA symbols of each of the first slot and the second slot of the SRS subframe.
4. The method of claim 1 , wherein, if the HARQ ACK/NACK are to be transmitted in the same subframe, the DM-RS is received in three SC-FDMA symbols of each of a first slot and a second slot of the SRS subframe and the HARQ ACK/NACK is received in four SC-FDMA symbols of the first slot of the SRS subframe and three SC-FDMA symbols of the second slot of the SRS subframe.
5. A base station (BS) configured to transmit a downlink subframe in a wireless communication system, the base station comprising:
a radio frequency (RF) unit configured to receive and transmit radio signals; and
a processor coupled to the RF unit and configured to:
control the RF unit to transmit a simultaneous transmission indicator to a user equipment (UE) that indicates whether a sounding reference signal (SRS) and a hybrid automatic retransmission request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK) are to be transmitted by the UE in a same subframe;
control the RF unit to transmit SRS operation information to the UE that indicates a periodicity of transmission of the SRS and a subframe offset to be used for the transmission of the SRS;
control the RF unit to receive the SRS, the HARQ ACK/NACK and a demodulation reference signal (DM-RS) from the UE when the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are to be transmitted in the same subframe, the DM-RS used by the BS to demodulate the HARQ ACKNACK in an SRS subframe; and
control the RF unit to receive the HARQ ACK/NACK and the DM-RS from the UE in the SRS subframe without the SRS when the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are not to be transmitted in the same subframe,
wherein the SRS is received in a last single carrier-frequency division multiple access (SC-FDMA) symbol of the SRS subframe, and
wherein the HARQ ACK/NACK and the DM-RS are received in remaining SC-FDMA symbols of the SRS subframe.
6. The base station of claim 5 , wherein the SRS operation information facilitates determining the SRS subframe among a plurality of subframes.
7. The base station of claim 5 , wherein, if the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are not to be transmitted in the same subframe, the processor is further configured to:
control the RF unit to receive the DM-RS in three SC-FDMA symbols of each of a first slot and second slot of the SRS subframe and to receive the HARQ ACK/NACK in four SC-FDMA symbols of each of the first slot and the second slot of the SRS subframe.
8. The base station of claim 5 , wherein, if the simultaneous transmission indicator indicates that the SRS and the HARQ ACK/NACK are to be transmitted in the same subframe, the processor is further configured to:
control the RF unit to receive the DM-RS in three SC-FDMA symbols of each of a first slot and a second slot of the SRS subframe and to receive the HARQ ACK/NACK in four SC-FDMA symbols of the first slot of the SRS subframe and three SC-FDMA symbols of the second slot of the SRS subframe.