Abstract—In this paper, we present two simplified scenarios for interference mitigation in overlay cognitive radio systems. These schemes are based on either optimizing the secondary user transmitter-only or the secondary user receiver-only without any changes to the existing primary user system in order to minimize the secondary system mean-square error (MSE) and the excess mean-square error at the primary system. These schemes are compared to a system that jointly optimizes the transmitter and receiver for the secondary system resulting in high complexity. Analytical and simulations results for the mean-square error under different cross-talk interference levels are presented in this paper. The results show that the receiver-only optimization incurs about 5 dB degradation in the secondary user MSE compared to the optimal system that jointly optimizes transmitter and receiver. It is also shown the receiver-only optimization does not degrade the excess MSE performance for the primary user causing minimal increase in the interference level. On the other hand, optimizing the transmitter-only results in a slightly small improvement to the primary system excess MSE and hence reducing the interference, but it fails in providing acceptable performance for the secondary user resulting in about 25dB degradation in MSE.

Index Terms—Cognitive radio (CR), crosstalk, mean square error (MSE), overlay system.

M. Vameghestahbanati is with the Department of Systems and Computer Engineering, Carleton University, PO Box K1S 5B6 Ottawa, Canada (e-mail: moniroshariehvameghe@sce.carleton.ca).
H. Mir and M. El-Tarhuni are with the Department of Electrical Engineering of American University of Sharjah, PO Box 26666 Sharjah, United Arab Emirates (e-mail:hmir@aus.edu, mtarhuni@aus.edu).

Cite:Monirosharieh Vameghestahbanati, Hasan S. Mir, and Mohamed El-Tarhuni, "Simplified Overlay Architecture for Cognitive Wireless Systems," International Journal of Computer and Communication Engineering vol. 3, no. 6, pp. 394-397, 2014.