A comparative study of pilot-based channel estimators for wireless OFDM

In English This report deals with pilot-based channel estimation in wireless OFDM systems. We assume that the receiver is able to use all transmitted pilots, which is the case in broadcasting and in the downlink of a multiuser system. Four estimators (of which two have been proposed in the literature) are compared, both in terms of mean-squared error and bit-error rates. In the latter case, we simulate a multiuser system which incorporates channel coding. The channel estimation is a two-dimensional problem (time and frequency), and both separable and non-separable estimators are investigated. We design low-rank approximations of these estimators, and compare the performance at given complexities. The comparison shows that the use of separable estimators increases the performance substantially, compared to non-separable estimators with the same complexity. For the scenario investigated in this report the performance is further improved by applying low-rank approximations to separable estimators.