Method of transmitting data in multiple antenna system
A method of transmitting data in a wireless communication system comprises receiving feedback data on an uplink data channel, the feedback data comprising a precoding matrix indicator (PMI), wherein the value of the PMI corresponds to an index in a codebook, transmitting a precoding scheme for downlink data on a downlink control channel, wherein the preceding scheme is determined as one of at least two of a transmit diversity irrespective of the received PMI, an acknowledgement indicating precoding according to the received PMI and a new PMI indicating that it is used in precoding downlink data to be transmitted, and transmitting the downlink data on a downlink data channel after applying precoding according to the determined precoding scheme.
1. A method of transmitting data in a wireless communication system, the method comprising:
receiving feedback data on an uplink data channel, the feedback data comprising a preceding matrix indicator (PMI), wherein the value of the PMI corresponds to an index in a codebook;
transmitting a precoding scheme for downlink data on a downlink control channel, wherein the precoding scheme is determined as one of at least two of a transmit diversity irrespective of the received PMI, an acknowledgement indicating precoding according to the received PMI and a new PMI indicating that it is used in precoding downlink data to be transmitted; and
transmitting the downlink data on a downlink data channel after applying precoding according to the determined precoding scheme.
2. The method of claim 1 , wherein the precoding scheme is determined as the transmit diversity when error in the feedback data is detected by using cyclic redundancy check (CRC) attached to the feedback data.
3. The method of claim 1 , wherein the precoding scheme is determined as the new PMI indicating that it is used in precoding according to the latest received PMI.
4. The method of claim 1 , wherein the transmit diversity includes a space frequency block code (SFBC) and a cyclic delay diversity (CDD).
5. The method of claim 1 , wherein the feedback data comprise a plurality of PMIs, each of the plurality of PMIs being selected from the codebook for each subband.
6. The method of claim 1 , wherein the feedback data comprise a frequency flat PMI on a plurality of subbands and a frequency selective PMI on selected subbands of the plurality of subbands.
7. A method of processing data in a wireless communication system, the method comprising:
configuring feedback data comprising at least one PMI, wherein the value of a PMI corresponds to an index in a codebook;
reporting the feedback data on an uplink data channel;
receiving a precoding scheme for downlink data on a downlink control channel, wherein the precoding scheme is determined as a transmit diversity irrespective of the reported PMI or a precoding matrix which is used to precode the downlink data; and
receiving the downlink data on a downlink data channel.
8. The method of claim 7 , wherein the feedback data comprise a plurality of PMIs on a plurality of subbands and one wholeband CQI on the plurality of subbands.
9. The method of claim 7 , wherein the feedback data comprise a first PMI on a plurality of subbands, a second PMI on selected subbands of the plurality of subband, one wholeband CQI on the plurality of subbands and one CQI on the selected subbands of the plurality of subbands.