Weight tracking method for OFDM adaptive array in time variant fading channel

In an orthogonal frequency division multiplexing (OFDM) system, in order to remove the influence of co-channel interference (CCI), the minimum mean square error-adaptive array antenna (MMSE-AAA) is attractive. To get the space diversity gain, the distance between adjacent elements should be set to be more than several wavelengths. However, it is difficult to derive the optimal weights with a few training symbols because the fading status is independent in each element. As a result, the bit error rate (BER) performance is deteriorated. We propose a novel weight tracking method to achieve space diversity gain and fast convergence with a few pilot symbols. In the proposed method, before updating the weight, channel estimation is applied to track the multipath fading of the desired signals. By computer simulation, we show that the proposed system improves the BER performance compared to the conventional system without channel estimation, even if the Doppler frequency is high.