Iterative joint sequence and channel estimation for fast time-varying intersymbol interference channels

We propose an iterative algorithm which iterates between a maximum-likelihood channel estimator and a maximum-likelihood sequence estimator (Viterbi algorithm) to jointly estimate channel impulse response and detect transmitted data. The algorithm is designed so that the data sequences are detected on a block-by-block basis. For each received block of data, the channel impulse response is assumed to be unknown and must be estimated each time. Because each block of data is treated separately and detected independently, this approach could be useful for fast time-varying intersymbol interference channels. Simulation results show the symbol error probability of the algorithm follows closely the performance of a maximum-likelihood sequence estimation receiver that knows the channel impulse response.