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Journal of Electrical and Computer Engineering
Volume 2011, Article ID 176486, 6 pages
http://dx.doi.org/10.1155/2011/176486
Research Article

Effect of Correlated Non-Gaussian Quadratures on the Performance of Binary Modulations

1Department of Computer & Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL 33431, USA
2Department of Digital Systems, University of Piraeus, 80 Karaoli and Dimitriou Street, 18534 Piraeus, Greece

Received 14 January 2011; Accepted 31 March 2011

Academic Editor: Nikos Sagias

Copyright © 2011 Valentine A. Aalo and George P. Efthymoglou. 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

The received signal in many wireless communication systems comprises of the sum of waves with random amplitudes and random phases. In general, the composite signal consists of correlated nonidentical Gaussian quadrature components due to the central limit theorem (CLT). However, in the presence of a small number of random waves, the CLT may not always hold and the quadrature components may not be Gaussian distributed. In this paper, we assume that the fading environment is such that the quadrature components follow a correlated bivariate Student-t joint distribution. Then, we derive the envelope distribution of the received signal and obtain new expressions for the exact and high signal-to-noise (SNR) approximate average BER for binary modulations. It also turns out that the derived envelope pdf approaches the Rayleigh and Hoyt distributions as limiting cases. Using the derived envelope pdf, we investigate the effect of correlated nonidentical quadratures on the error rate performance of digital communication systems.