Cooperative Diversity in Secondary Systems: Efficient Relaying Protocol for Cognitive Radio

Abstract

This paper considers half-duplex cooperative spectrum sharing scheme where both primary and secondary systems mutually cooperate with each other to exploit cooperative diversity in both the systems. Unlike existing cooperative schemes, this proposed protocol achieves cooperative diversity at the secondary (unlicensed) user without degrading the spectral efficiency and bit error rate (BER) performance of the primary (licensed) user. We present the closed-form expression for average BER of both primary and secondary receivers. Moreover, we compare our results with the recently proposed schemes to substantiate the efficacy of our protocol.