Adaptive Channel Estimation and Equalization for Rapidly Mobile Communication Channels

Adaptive Channel Estimation and Equalization for Rapidly Mobile Communication Channels The paper presents a reduced-complexity maximum-likelihood sequence estimation receiver, based on the Viterbi algorithm (VA), suitable for rapidly fading mobile communication channels. The channel impulse response is expanded onto a set of basis sequences and time-invariant (TI) expansion parameters. The proposed receiver continuously estimates the time instant of the VA, the accumulated metrics of the survivor paths are compared, and the survivors whose metrics are lower than the average value of the accumulated survivor metrics are retained. The other survivors are used to update the estimate of the TI expansion parameters. The convergence properties of the estimation algorithm are investigated, and the steady-state value of the mean square error or estimation is derived. The performance of the proposed receiver, in terms of the symbol-error probability, is compared with other receivers. The effects of time offset and frequency offset on the performance of receiver are studied.