Maximization of end to end throughput of cognitive radio network using cooperative relay channels

Spectrum scarcity is one of the primary bottlenecks for the future wireless communication systems, for better spectrum utilization cognitive radio plays a vital role. Cognitive radio is a new paradigm of designing wireless communications systems which aims to enhance the utilization of the radio frequency (RF) spectrum for wireless communications. Available spectrum bands may vary with different cognitive radio users. It happens when the transmission range of cognitive radio users is larger than or similar to that of primary user. Then different cognitive radio users may obtain different sensing results since they are at different locations and different impacts on primary user systems. In order to establish this challenging adaptation, cooperative relay channel has been introduced in a network to enhance the end to end throughput in terms of power and bandwidth constraints. The proposed cooperative relay diversity method employs three sorts of parallel end-to-end transmission scenarios comprising of direct, dual-hop, and relay diversity transmission. Therefore, the overall end-to-end communication has been achieved by the use of three kinds of channels occupying four spectrum bands. The total throughput is obtained by the summation of three kinds of transmission since multiple transmissions may happen simultaneously in cognitive radio relay channel (CRRC). Performance metrics such as throughput in terms of power and channel constraints has been analyzed. Simulation has been carried out using MATLAB R2009b.