Impact of timing error on BER performance of TDD pre-equalized OFDM systems

The TDD pre-equalized OFDM systems have a mighty significant advantage of saving system resource by omitting the pilot symbols. Along with that, there is a limitation that the timing error can not be revised in the absence of pilot symbols. In this paper we investigate the impact of timing error on the receiver´s BER performance of TDD pre-equalized OFDM systems. We obtain the analytic BPSK BER expressions of ideally and nonideally pre-equalized OFDM systems in multipath Rayleigh fading environment. The corresponding simulations verify the analytic expressions. Compared with the theoretical system performance bound, the performance of ideal and nonideal pre-equalization entail loss of 1db and 3db respectively when the normalized timing error is 1/8. When it is 1/4, both of the two systems´ performances degrade severely. At the same time, the gap between them diminishes. In that case, timing error becomes dominant among those elements which would affect system performance.