Analysis and evaluation of subband adaptive array under multipath fading condition

The subband adaptive array (SBAA) is a method for the parallel implementation of the tapped delay line adaptive array (TDLAA) which possesses high ability to mitigate the degradation of the quality of wireless communications under the environment where plural coherent propagation waves are arriving from different directions (multipath fading environment). This paper presents a unified analytical overview and an evaluation criterion for SBAA accompanied with sampling rate conversion. Here the signal-to-interference-plus-noise ratio (SINR) is adopted as quality factor and the performance of the SBAA under multipath fading is investigated theoretically based on this criterion. As an improvement for the SBAA, the cyclic prefix (CP) which is used in orthogonal frequency division multiplexing (OFDM) communication systems is introduced and experimentally verified to be effective through computer simulations. This paper demonstrates the advantage of this approach from the analytical viewpoint with respect to the correlation matrix in each band.