Abstract: There are many subchannels in the Orthegonal Frequency Division Multiplexing(OFDM). Based on the central limit theorem, the noise components of every subchannels receiver output can be shown to be the complex Gaussian with the zero mena. The error bit ratio (BER) performance formula for the block precoded OFDM system with zero forcing and squared error (MMSE) receivers in Rayleigh Raying channels is deduced in this paper. It is convenient to compare the BER performance of the different OFDM systems by the formula calculation. What is more, the actual BER obtained by the Monte Carlo simulation is identical with the BER by use of the formula.

Key words: block precoders, orthogonal frequency division multiplexing(OFDM), error bit ratio(BER)