Multistage interference cancellation using smart antennas

Due to rapid development of wireless communication techniques, versatile services, better quality and larger bandwidth are in demand. With the deployment of third generation wireless communication systems, high data rate wireless transmission will soon become the mainstream of the commercial market. It is expectable that such error sensitive data transmissions require more reliable channels than voice transmissions do. Smart antennas incorporated with other advanced techniques can effectively improve the quality and reliability of wireless channels.; Smart antennas (also known as adaptive arrays) can be used in both uplink (mobile-to-base) and downlink (base-to-mobile) transmissions for communication quality enhancement and increased channel capacity. In this work we focus on the application of smart antennas in uplink applications. Smart antennas reject the unwanted signals impinging at the receiver antenna array by adaptively adjusting the associated weight of each antenna element. This is called “interference cancellation” or “interference suppression.” By reducing interferences, the Signal-to-Interference-plus-Noise Ratio (SINR) is increased and the communication quality is improved. Many sophisticated adaptive algorithms have been proposed for such applications and have shown good performances in terms of rapid convergence and low steady-state Mean-Squared Error (MSE). However, the high computation load impedes the implementation of such algorithms in practice. On the other hand, low computational complexity algorithms are easier to implement in real world applications. However, they may suffer slow convergence in some circumstances.; In this work, a novel method, Multistage Interference Cancellation using Smart Antennas (MICSA), is proposed, which accelerates the convergence speed of these low computational complexity algorithms with little increase in low computational complexity.