Method and apparatus for feedback transmission in wireless communication system
A method and an apparatus for feedback transmission in a wireless communication system are provided. A terminal receives information about a short-term feedback period and a long-term feedback period from a base station, and then transmits to the base station short-term feedback information per short-term feedback period or long-term feedback information per long-term feedback period over a primary fast feedback channel (PFBSCH). The long-term feedback information contains an index of a subband subjected to channel measurement and a difference in measurement values that is a difference between a reference channel measurement value and a channel measurement value being measured.
1. A method of transmitting a feedback in a wireless communication system, the method comprising:
receiving information on a short-term feedback period and a long-term feedback period from a base station; and
transmitting short-term feedback information by the short-term feedback period or long-term feedback information by the long-term feedback period to the base station on a primary fast feedback channel (PFBCH),
wherein the long-term feedback information comprises an index of a subband which is a subject of channel measurement and a difference measurement value which is a difference between a reference channel measurement value and a measured channel measurement value,
wherein the long-term feedback information is the index of the subband and an index indicating feedback information of a PFBCH encoding type 1 corresponding to the difference measurement value,
wherein the index indicating the feedback information of the PFBCH encoding type 1 is an integer which is one of 1 to 55,
wherein the difference measurement value is a difference value between a previously transmitted channel quality indicator (CQI) and a measured CQI; and
wherein transmitting the short-term feedback information or the long-term feedback information comprises generating a feedback sequence based on the short-term feedback information or the long-term feedback information; mapping the generated feedback sequence to a feedback symbol by modulating and repeating the generated feedback sequence; and mapping the feedback symbol to subcarriers allocated to the feedback channel.
2. The method of claim 1 , wherein the difference measurement value is represented by a difference of actual transmission power or by a difference of a modulation and coding scheme (MCS) level.
3. The method of claim 1 , wherein the difference measurement value is a difference between a previously transmitted precoding matrix indicator (PMI) and a measured PMI.
4. The method of claim 1 , wherein the difference measurement value is an index difference when a correlation between a previously transmitted PMI and a measured PMI is represented by an index.
5. The method of claim 1 , wherein the long-term feedback period is an odd-numbered multiple of the short-term feedback period.
6. An apparatus for transmitting a feedback in a wireless communication system, the apparatus comprising:
a radio frequency (RF) unit configured for receiving information on a short-term feedback period and a long-term feedback period and to transmit short-term feedback information by the short-term feedback period or long-term feedback information by the long-term feedback period on a primary fast feedback channel (PFBCH), and
a processor, coupled to the RF unit, configured for processing the short-term feedback information or the long-term feedback information,
wherein the long-term feedback information comprises an index of a subband which is a subject of channel measurement and a difference measurement value which is a difference between a reference channel measurement value and a measured channel measurement value,
wherein the long-term feedback information is the index of the subband and an index indicating feedback information of a PFBCH encoding type 1 corresponding to the difference measurement value,
wherein the index indicating the feedback information of the PFBCH encoding type 1 is an integer which is one of 1 to 55,
wherein the difference measurement value is a difference value between a previously transmitted channel quality indicator (CQI) and a measured CQI, and
wherein the RF unit, in transmitting the short-term feedback information or the long-term feedback information, is further configured to generate a feedback sequence based on the short-term feedback information or the long-term feedback information; map the generated feedback sequence to a feedback symbol by modulating and repeating the generated feedback sequence; and map the feedback symbol to subcarriers allocated to the feedback channel.
7. The apparatus of claim 6 , wherein the difference measurement value is a difference between a previously transmitted precoding matrix indicator (PMI) and a measured PMI.
8. The apparatus of claim 6 , wherein the long-term feedback period is an odd-numbered multiple of the short-term feedback period.