Performance Comparison of Modulation Techniques for Underlay Cognitive Radio Transceivers

Abstract

In this paper, we present a quantitative comparison of two agile modulation techniques employed by cognitive radio transceivers operating in a dynamic spectrum access (DSA) network. One of the modulation techniques is single carrier frequency division multiple access (SC-FDMA). The other modulation technique under study is a variant of multicarrier code division multiple access (MCCDMA). Although several studies comparing conventional OFDM and MC-CDMA has been conducted in literature to justify robust error performance of MC-CDMA, a quantitative performance evaluation of these schemes has not been performed when employed in a DSA network. In this paper we show that their performances can be significantly different from the conventional setup. Analytical expressions for the error probability of an SC-FDMA transceiver have been derived and compared with computer simulation results. The results show that the error robustness of SC-FDMA is relatively better then MC-CDMA in underlay communication.