Maximal Ratio Combining Subband Adaptive Array Using Decision Feedback Approach

This paper presents a maximal ratio combining (MRC) subband adaptive array using decision feedback approach. The subband adaptive array could extend the MRC scheme for frequency flat environments to be used in frequency selective channels, but the nonuniqueness of subband weights with respect to their phase rotation disturbs the efficient synthesis of output signal through the inverse DFT (discrete Fourier transform). Our method adopts two-step approach to solve this problem: In the first step, we use simple phase adjustment and derive hard-decision temporary output. Then in the second step, it is used as a training sequence to determine optimum phase compensation. Though this idea seems very simple, the proposed scheme significantly improves the performance of MRC based adaptive array and it is verified through computer simulations together with some features.