Gradient Signal Processing Algorithm for Adaptive Antenna Arrays Obviating Reference Signal Presence

Abstract

Signal processing algorithms in adaptive antenna arrays are analyzed with respect to their application in mobile telecommunication systems. It is established that both in literature and in practice insufficient attention is paid to search for and design of such simple adaptation algorithms that do not require presence of the reference signal. Gradient method of adaptation is considered and its limitations are exposed. It is shown that the gradient method requires a reference signal that can be presented as the signal in a selected antenna element or a reference signal generated in the antenna array. A simple algorithm of antenna array adaptation is deduced that operates in the absence of the reference signal. Computer simulation of adaptive antenna arrays with the designed algorithm in different situations is carried out, which singles out inherent deficiency in the algorithm. Improvements to eliminate this deficiency are offered. High performance of the improved gradient algorithm is confirmed in difficult interference environments.