Research on Communication Performance of Dual-Time-Slot RIS-DF Cooperative System Model

可重构智能表面(Reconfigurable Intelligent Surface, RIS)被认为是一种可以通过自适应调整信号反射相位来提高通信系统性能的技术，在当下6G网络时代备受关注。为了充分利用RIS与传统中继各自的传输优势，本文在衰落信道服从独立且不同Nakagami-m分布下，提出了RIS与解码转发(Decode and Forward, DF)中继协作通信系统模型。考虑信号传输在两个时隙中进行，对多RIS进行选择以参与不同时隙的信号传输，推导双时隙协作传输方案下系统的信噪比闭式表达，基于该表达式进一步分析系统的中断概率性能，研究系统中信号发射功率和反射元件个数对系统的影响。在随机生成RIS部署位置的多变条件下，通过数值模拟验证理论模型的准确性和有效性。结果表明，本文提出的双时隙协作通信系统模型优于单时隙RIS辅助传输或无任何辅助的传输方案。Reconfigurable Intelligent Surface (RIS) is recognized as a technology capable of enhancing communication system performance by adaptively adjusting the phase of reflected signals, attracting significant attention in the current era of 6G networks. To fully leverage the respective transmission advantages of RIS and conventional relays, this paper proposes a cooperative communication system model integrating RIS with Decode-and-Forward (DF) relays under independent and non-identical Nakagami-m fading channels. Considering signal transmission over two-time slots, we select multiple RISs to participate in signal transmission during different time slots. A closed-form expression for the Signal-to-Noise Ratio (SNR) under the dual-time-slot cooperative transmission scheme is derived. Based on this expression, the system outage probability performance is further analyzed, and the impacts of transmitting power and the number of reflective elements on the system are investigated. Numerical simulations under varying conditions of randomly generated RIS deployment positions validate the accuracy and validity of the theoretical model. The results demonstrate that the dual-time-slot cooperative communication system model proposed in this paper outperforms single-time-slot RIS-assisted transmission schemes and non-assisted transmission schemes.