Semi-grant-free (SGF) transmission scheme enables grant-free (GF) users to utilize resource blocks allocated for grant-based (GB) users while maintaining the quality of service of GB users. This work investigates the secrecy performance of non-orthogonal multiple access (NOMA)-aided SGF systems. First, analytical expressions for the exact and asymptotic secrecy outage probability (SOP) of NOMA-aided SGF systems with a single GF user are derived. Then, the SGF systems with multiple GF users and the best-user scheduling scheme is considered. Analytical expressions for the exact and asymptotic SOP are derived by utilizing order statistics theory. Monte Carlo simulation results are provided and compared with two benchmark schemes. The effects of system parameters on the SOP of the considered system are demonstrated and the accuracy of the developed analytical results is verified. The results indicate that both the outage target rate for GB and the secure target rate for GF are the main factors of the secrecy performance of SGF systems.
翻译:这项工作调查了非横向多重准入(NOMA)辅助的 SGF系统的保密性表现。首先,对NOMA协助的SGF系统与单一的GF用户的准确和无记名保密性超值概率的分析表达方式(SOP)得到推算;然后,考虑到拥有多个GF用户的SGF系统以及最佳用户排期计划。精确和无记名 SOP的分析表达方式是通过使用命令统计理论得出的。蒙特卡洛模拟结果与两个基准计划进行比较。对所考虑的系统SOP的系统参数效果进行了演示,并核实了开发分析结果的准确性。结果显示,GB的超值目标率和GF的安全目标率是SGF系统保密性表现的主要因素。</s>