Weighted downlink beamforming algorithm in mobile communication

Abstract

In recent times, an immense increase in traffic has been experienced by wireless communication systems, due to a significant growth of number of users and the development of new high bit rate applications. It is expected that soon this trend will be established. This challenging scenario involves not only a well-established market of cellular systems, but also a field of emerging wireless technologies, such as WiMAX (Worldwide Interoperability for Microwave Access) for wireless metropolitan area networks, and Wi-Fi (Wireless Fidelity) for wireless local-area networks, mobile ad-hoc networks and wireless mesh networks. In order to satisfy the increasing demand of network capacity, the exploitation of spatial domain of communication channel using multiple antenna systems can be a critical improvement for enhancing the spectral efficiency of wireless systems. The combination of antenna arrays and beamforming algorithms can suppress the undesired sources and receive the signals incoming from the desired ones. Downlink beamforming is a well-known technique to reduce strong interferences effectively induced by high data rate users. Different weighted beamforming methods for downlink transmission in cellular mobile communication systems using an antenna array at the base station are presented. The techniques are based on estimation of beam patterns in terms of the desired, and the interference signals at the base transceiver station using different weighted beamforming algorithms. Beam-patterns for a special case of three mobiles, uniform linear array at the base station are obtained using two well-known algorithms.