Nakagami-m信道下无人机辅助的速率分拆多址接入协作通信系统性能研究

Performance Investigation of Unmanned Aerial Vehicle Assisted Rate Splitting Multiple Access Cooperative Communication Systems in Nakagami-m Fading Channels

针对多用户通信资源短缺、分配不均衡的问题,该文研究了基于速率分拆多址接入技术(RSMA)的无人机(UAV)辅助多用户下行通信网络。在复杂的实际通信环境中,频率复用所引起的无用信号的干扰不可避免,考虑无人机与各用户节点信息传输受共道干扰影响,在Nakagami-m衰落信道下推导了该无人机协作通信系统的中断概率和信道容量的精确闭式表达式,证明共道干扰的存在使得高信噪比(SNR)区域系统的分集阶数为0。结果表明,在相同的空间模型下,采用RSMA通信方案的系统性能优于非正交多址(NOMA)方案;无人机飞行速度增大时,地-空通信建立视距链路的概率降低,系统中断性能下降。因此,在满足用户实际通信的需求时需要综合考虑无人机飞行速度、多址接入方式、系统性能以及通信连通性,以实现对无人机通信系统整体的有效权衡。

The challenges of scarce communication resources and uneven allocation in multi-user communication networks are investigated in the article with a focus on the Unmanned Aerial Vehicle(UAV)-assisted multi-user downlink communication network using Rate Splitting Multiple Access(RSMA)technology.In complex realworld communication environments,interference caused by useless signals due to frequency reuse is inevitable.Considering the co-channel interference affecting the data transmission between UAV and various user nodes in Nakagami-m fading channels,precise closed-form expressions for the outage probability and channel capacity of the system are derived.It is demonstrated that the diversity order is 0 resulted from the presence of co-channel interference for high Signal-to-Noise Ratio(SNR)regime systems.Moreover,under the same spatial model,the system performance using the RSMA communication scheme is superior to the Non-Orthogonal Multiple Access(NOMA)scheme.As the flight speed of UAV increases,the probability of establishing line-of-sight links for ground-to-air communication is decreased,leading to a degradation in system outage performance.Therefore,effective trade-offs for the overall UAV communication system need to be achieved by comprehensively considering the flight speed of UAV,multiple access methods,system performance,and communication connectivity,in order to meet the practical communication needs of users.