摘要 : We investigate the performance of a cognitive spectrum sharing system where a best selected secondary user (SU) assists two-way communication between two primary users (PUs) by employing time division broadcast over Rayleigh chann... 展开 We investigate the performance of a cognitive spectrum sharing system where a best selected secondary user (SU) assists two-way communication between two primary users (PUs) by employing time division broadcast over Rayleigh channels. We derive tight lower-bound expressions for the overall outage probability (OOP) of both the primary and secondary systems of the considered scheme. We also provide valuable insights into the achievable diversity order, cell coverage, and optimal power allocation factor to ensure spectrum sharing. Numerical and simulation results corroborate the theoretical analysis and illustrate the effectiveness of the considered scheme. 收起