Method of generating channel quality indicator adaptively in downlink status and user equipment for the same

A user equipment (UE) for transmitting channel quality information in a mobile communication system, the UE comprising:

• a measuring unit that generates at least one channel quality indicator (CQI) for one or more subbands in a frequency domain, and
• a transmitter that transmits the at least one CQI,
• wherein a size of one subband of the one or more subbands corresponds to an integer multiple of a unit frequency band for downlink resource allocation,
• wherein the integer multiple is an integer having a value of 2 or more, and
• wherein the unit frequency band comprises plural subcarriers,
• wherein the transmitter transmits a combinatorial index,
• wherein the combinatorial index is associated with one of a total number possible combinations NCM when M subbands are selected from N subbands, so as to indicate which subbands are selected as the one or more subbands,
• where NCM is defined as
• N
• !
• M
• !
• ⁢
• (
• N
• -
• M
• )
• !
• ,
• where M is integer indicating a number of the one or more subbands, N is integer indicating a number or whole subbands of an entire downlink system bandwidth, and 1≤M<N, and
• wherein a number of bits used to represent the combinatorial index is ┌log2(NCM)┐.

A method for receiving channel quality information from a base station (BS) in a mobile communication system, the method performed by the BS and comprising:

• receiving at least one channel quality indicator (CQI) for one or more subbands in a frequency domain;
• processing the at least one CQI;
• wherein a size of one subband of the one or more subbands corresponds to an integer multiple of a unit frequency band for downlink resource allocation,
• wherein the integer multiple is an integer having a value of 2 or more, and
• wherein the unit frequency band comprises plural subcarriers;
• and
• receiving a combinatorial index,
• wherein the combinatorial index is associated with one of a total number possible combinations NCM when M subbands are selected from N subbands, so as to indicate which subbands are selected as the one or more subbands,
• where NCM is defined as
• N
• !
• M
• !
• ⁢
• (
• N
• -
• M
• )
• !
• ,
• where M is integer indicating a number of the one or more subbands, N is integer indicating a number or whole subbands of an entire downlink system bandwidth, and 1≤M<N, and
• wherein a number of bits used to represent the combinatorial index is ┌log2(NCM)┐.

A base station (BS) for receiving channel quality information in a mobile communication system, the BS comprising:

• a receiver that receives at least one channel quality indicator (CQI) for one or more subbands in a frequency domain, and
• a processing unit that processes the at least one subband CQI,
• wherein a size of one subband of the one or more subbands corresponds to an integer multiple of a unit frequency band for downlink resource allocation,
• wherein the integer multiple is an integer having a value of 2 or more, and
• wherein the unit frequency band comprises plural subcarriers,
• wherein the receiver receives a combinatorial index,
• wherein the combinatorial index is associated with one of a total number possible combinations NCM when M subbands are selected from N subbands, so as to indicate which subbands are selected as the one or more subbands,
• where NCM is defined as
• N
• !
• M
• !
• ⁢
• (
• N
• -
• M
• )
• !
• ,
• where M is integer indicating a number of the one or more subbands, N is integer indicating a number or whole subbands of an entire downlink system bandwidth, and 1≤M<N, and
• wherein a number of bits used to represent the combinatorial index is ┌log2(NCM)┐.