A Variable Length Linear Array for Smart Antenna Systems

Adaptive arrays have been used extensively in wireless communications applications to reduce interference between desired users and interfering signals. In particular a large concentration of research has been directed to the uniform linear array (ULA). However in most situations presented the authors utilise a fixed array length. In a mobile environment this has the disadvantage of producing a fixed beamwidth due to the fixed array length. This paper proposes an algorithm which can be used to determine the required beamwidth for a number of incoming signals by altering the length a specified number of elements present in an antenna array. This is achieved by the difference in the arrival angle of the desired user and a range incoming interferers known having a varied angle spread. The least mean square (LMS) algorithm is incorporated into the algorithm for optimisation of the radiation pattern