Performance analysis of subband arrays

Several subband array methods have been proposed as useful means to perform joint spatio-temporal equalization in digital mobile communications. These methods can be applied to mitigate problems caused by the inter-symbol int erference (ISI) and co-channel interference (CCI). The subband array method s proposed so far can be classified into two major schemes: (1) a centraliz ed feedback scheme and (2) a localized feedback scheme. In this paper, we p ropose subband arrays with partial feedback scheme, which generalize the ab ove two feedback schemes. The main contribution of this paper is to derive the steady-state mean square error (MSE) performance of subband arrays impl ementing these three different feedback schemes. Unlike the centralized fee dback scheme which can be designed to provide the optimum equalization perf ormance, the subband arrays with localized and partial feedback schemes are in general suboptimal. The performance of these two suboptimal feedback sc hemes depends on the channel characteristics, the filter banks employed, an d the number of subbands.