Channel estimation for OFDM communication systems

A method for estimating a frequency response of a wireless channel in an orthogonal frequency division multiplexing (OFDM) communication system, comprising

• obtaining an initial estimate of the frequency response of the wireless channel for a first group of subbands based on a pilot transmission received via the subbands in the first group, wherein the first group of subbands is a subset of all subbands usable for data transmission;
• and
• deriving an enhanced estimate of the frequency response of the wireless channel for the usable subbands based on the initial frequency response estimate, wherein the enhanced frequency response estimate is derived based on an estimate of an impulse response of the wireless channel that is implicitly or explicitly derived based on the initial frequency response estimate, and wherein the enhanced frequency response estimate is further derived based on a first discrete Fourier transform (DFT) matrix for the subbands in the first group and a second DFT matrix for the usable subbands.

A method for estimating a frequency response of a wireless channel for each of a plurality of terminals in a wireless communication system, comprising

• obtaining an initial estimate of the frequency response of the wireless channel for each of the plurality of terminals, wherein each of the plurality of terminal is associated with a respective one of a plurality of disjoint groups of subbands, and wherein the initial frequency response estimate for each terminal is obtained for the associated group of subbands based on a pilot transmission received via the subbands in the associated group;
• and
• deriving an enhanced estimate of the frequency response of the wireless channel for each of the plurality of terminals based on the initial frequency response estimate for the terminal, wherein the enhanced frequency response estimate for each terminal covers a particular set of subbands and is derived based on an estimate of an impulse response of the wireless channel for the terminal that is implicitly or explicitly derived based on the initial frequency response estimate for the terminal.

An apparatus operable to estimate a frequency response of a wireless channel, comprising

• means for obtaining an initial estimate of the frequency response of the wireless channel for a first group of subbands;
• and
• means for deriving an enhanced estimate of the frequency response of the wireless channel for a second group of subbands based on the impulse response estimate, wherein the enhanced frequency response estimate is derived based on an estimate of an impulse response of the wireless channel that is implicitly or explicitly derived based on the initial frequency response estimate.