Time versus frequency domain channel estimation for OFDM systems with antenna arrays

We compare channel estimation schemes in the time and frequency domains in terms of the error performance of both the estimated channel impulse response (CIR) and transfer function (TF) as well as the resulting bit-error rate (BER) in an orthogonal frequency-division multiplexing (OFDM) system with a time-multiplexed preamble. If the total number of sub-carriers, K, exceeds the number of taps, L, in the CIR, as is the case in most practical OFDM systems, the TF estimate based on the time domain least squares (LS) scheme is more accurate than the one obtained from direct LS estimation in the frequency domain. An equivalent mean-squared error performance results for the case K=L.