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

Abstract

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.