Spatial-domain path-diversity using an adaptive array for mobile communications

Frequency-selective fading due to multipath propagation is serious hindrance in high-speed TDMA mobile transmission. The multipath propagation causes degradation because signals with different delay times are received. If we resolve the signals and combine them adjusting the delay difference, we can both reduce the frequency-selective fading and utilize the transmitted signal power efficiently. This technique is called path-diversity. A RAKE receiver realizes the path-diversity in a time domain. We propose an adaptive array with several sets of complex weights. Each set of the complex weights forms a different array pattern. The weights are determined by an SMI (sample matrix inverse) algorithm. The adaptive array resolves multipath components adjusting the array patterns. Thus, we ran realize spatial-domain path-diversity for high-speed mobile communications.