A cooperative transmission scheme of secondary user in cognitive radio networks

Primary users and secondary users coexist in cognitive wireless networks at the same time, so the communication behaviour of secondary users must not affacts the data transmission of primary users. In order to guarantee the transmission continuity of secondary users and improve QoS of secondary users, researchers propose the strategy of mutual cooperative transmission between secondary users. The article proposes a dual-relay cooperative transmission scheme based on amplify and forward and carry out a detailed theoretical analysis on conflict-free transmission time and BER. Monte Carlo simulation results show that, dual-relay cooperative transmission strategy further increases conflict-free transmission time of secondary users than single-relay cooperative transmission and reduce BER Dual-relay cooperative transmission significantly improves the transmission performance of system.