On the Analysis of Multisource Cooperative Network Assisted by UAV Relays With Co-Channel Interference

With the rapid growth in the number of communication devices, there is a sharp increase in the demand for quality of service in wireless networks. To meet the requirements of high stability, low latency, and high reliability in wireless communications, uncrewed aerial vehicle (UAV) communication has become a critical solution for enhancing performance of future wireless networks. Addressing the demands for fast response of communication devices and flexible coverage in complex, diverse, and flexible emerging communication scenarios, a multisource multi-UAV cooperative relay communication system with co-channel interference is studied in the presence of direct links between source nodes and destination nodes. To enhance the interference resilience for the system understudy, two receiver diversity combining techniques, namely maximum ratio combining (MRC) and selection combining (SC), are proposed to combine the signals received by the direct link and UAV link at the destination node. Based on the two-step source-relay selection protocol, optimal source node is first selected to broadcast signals to multiple UAV relays and destination nodes, and then the optimal UAV relay is selected according to the selection cooperation scheme for improving the robustness of UAV cooperative relay systems. Performance analysis of considering multisource multi-UAV cooperative communication system is conducted by providing closed-form expressions for the exact outage probability, asymptotic outage probability, and ergodic capacity. Numerical simulations are provided to validate the theoretical analysis, and the results show that the multiple user diversity gain and cooperative diversity cannot be obtained due to the presence of co-channel interference. However, the damage caused by co-channel interference to the communication system can be compensated by increasing the number of source nodes or UAV relays.