Abstract:

ZPOFDM(zero padding orthogonal frequency division multiplexing)has the disadvantage that the simple FFT (fast fourier transform) based receiver does not perform well. Therefore, a pseudorandom sequence processing technique that is each row of the IFFT (inverse fast fourier transform) matrix multiplies with a bit of a pseudorandom sequence is proposed. The technique changes the correlation properties of the IFFT matrix columns, and hence improves the performance over multipath channels. The modified IFFT matrix is still unitary and orthogonal, since the multiplication by ±1 of the IFFT unitary matrix rows doesn't destroy its unitarity and orthogonality. This technique is analized theoretically and applied to ZPOFDM, ZPOFDMOLA and ZPOFDMFAST. Simulation results verify the improved performance of the modified methods using this technique. The Hiperlan2 Channel models A and E are considered in our simulation. For the two channel models, the modified methods exhibit at least 22?dB advantage in SNR at 10-4 BER （bit error rate）.

Key words: orthogonal frequency division multiplexing, pseudorandom sequence, correlation properties, channel state information, bit error rate