Mobile capacity enhancement using unequally spaced antenna arrays

Adaptive arrays can significantly increase cell capacity, improve signal quality, and reduce transmitter power requirements. In this paper, we investigate the capacity improvement that can potentially be achieved via an optimised design strategy for an unequally spaced array. We also investigate the effect that fading correlation has on the performance of an unequally spaced adaptive array. Results are presented for optimum combining with flat fading. Computer simulations show that it is possible to achieve a gain of at least 1.5 dB for moderate to high signal-to-noise ratios (SNR) when compared to the equally spaced array.