Subband Adaptive Array with Reduced Pilot Signal Using Maximal Ratio Combining Scheme

This paper presents a subband adaptive array (SBAA) with reduced pilot signal based on maximal ratio combining (MRC) scheme. By the subband processing, MRC design based on eigenfiltering which is widely used in frequency flat environments could be applied to frequency selective channels, but the efficient synthesis of output signal through the inverse DFT (discrete Fourier transform) is disturbed by the nonuniqueness of eigenvectors. In the proposed method, a two-step approach is adopted to solve this problem: in the first step, we use simple compensation of weight uncertainty with short (or possibly no) pilot signal and derive a hard-decision temporary output. Then in the second step, the output data is used as a training sequence to determine optimum compensation. It is shown through computer simulations that the proposed scheme improves the transmission rate of SBAA scheme keeping good performance, and some fundamental features are also investigated.