基于NR-U/WIFI共存的非授权频谱感知策略研究

毫米波非授权频谱可以解决日益加剧的频谱紧张问题。为了实现NR-U/WIFI公平共存，非授权频谱共享感知策略被提出来。由于NR-U系统的波束方向性，传统LBT非授权频谱感知策略存在严重的暴露节点和隐藏节点的问题，因此不再适用NR-U。为了解决这个问题，本课题提出新的基于波束方向的非授权频谱协作感知策略，主次用户通过在波束对齐方向上进行协作频谱感知，联合决定接入策略。通过可行性分析表明所提策略可有效解决漏报和虚警问题。本课题进一步考虑毫米波对障碍物的敏感性，分析障碍物对频谱感知接入的影响。首先利用随机形状理论和统计几何对障碍物进行建模和分析，然后理论分析网络性能限和影响。通过可行性分析发现,虽然障碍物对信号传输有一定的衰落作用,但对非授权频谱感知接入却起了一定的积极作用,提高了频谱接入概率和系统容量。

Unlicensed Millimeter wave can solve the urgent spectrum shortage problem. For the fair coexistence of NR-U/WIFI, spectrum sharing sensing strategy was proposed. Due to the beam directionality of the NR-U system, the traditional listen-before-talk (LBT) spectrum sensing strategy is no longer effective in the NR-U/WIFI system. To solve this, we propose a new cooperative spectrum sensing strategy based on the beam direction. In this strategy, primary and secondary users cooperatively sense the spectrum and jointly decide the access strategy. The analysis results show that the proposed strategy can effectively solve the hiding and exposing nodes problems of the traditional LBT strategy. We further take into account the sensitivity of millimeter wave, and analyze the effects of obstacles on the spectrum sharing sensing scheme. We first model the obstacles by exploiting the random shape theory and statistical geometry. Then, we analyze the network performance. Through the simulation results, it is found that although obstacles fade the signal, they have the positive effect on the unlicensed spectrum sensing. The obstacles increase the spectrum access probability and improve the system capacity.