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The Scientific World Journal
Volume 2014, Article ID 128195, 11 pages
http://dx.doi.org/10.1155/2014/128195
Research Article

Receiver Diversity Combining Using Evolutionary Algorithms in Rayleigh Fading Channel

1Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
2Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor, Malaysia

Received 23 February 2014; Revised 18 April 2014; Accepted 20 May 2014; Published 19 June 2014

Academic Editor: Dimitrios A. Karras

Copyright © 2014 Mohsen Akbari et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In diversity combining at the receiver, the output signal-to-noise ratio (SNR) is often maximized by using the maximal ratio combining (MRC) provided that the channel is perfectly estimated at the receiver. However, channel estimation is rarely perfect in practice, which results in deteriorating the system performance. In this paper, an imperialistic competitive algorithm (ICA) is proposed and compared with two other evolutionary based algorithms, namely, particle swarm optimization (PSO) and genetic algorithm (GA), for diversity combining of signals travelling across the imperfect channels. The proposed algorithm adjusts the combiner weights of the received signal components in such a way that maximizes the SNR and minimizes the bit error rate (BER). The results indicate that the proposed method eliminates the need of channel estimation and can outperform the conventional diversity combining methods.