In this study, a fair user-scheduling method is considered for an underlay cognitive radio system, in which the secondary users (SUs) are sharing the licenced frequency spectrum of a single primary user (PU), where the PU and SUs utilise Alamouti orthogonal space-time block coding (OSTBC). The impacts of some important practical issues are investigated in the system. First, it is assumed that the signal-to-noise-ratios of the SUs are independent non-identically distributed. Second, the transmit antennas for OSTBC corresponding to the SUs are assumed to be equally correlated. Third, the interference from the PU to SUs as well as the interferences from SUs to the PU are taken into consideration. To investigate the outage performance of the SUs, a closed-form expression for the cumulative distribution function of the SUs signal-to-interference-noise-ratio is obtained and then used to derive an expression for evaluating the secondary system outage performance. The numerically evaluated results, validated by computer simulations, provide insights about system outage performance under various practical situations on the impacts of the spatial antennas correlation and the PU interference on to SUs.

中文翻译：

---

使用具有相同相关的发射天线的OSTBC对认知无线电中的独立非相同分布用户的公平调度进行分析和中断性能评估

在这项研究中，针对底层认知无线电系统考虑了一种公平的用户调度方法，其中次要用户（SU）共享单个主要用户（PU）的许可频谱，其中PU和SU使用Alamouti正交时空块编码（OSTBC）。在系统中研究了一些重要的实际问题的影响。首先，假设SU的信噪比是独立的非相同分布的。其次，假定与SU相对应的用于OSTBC的发射天线是同等相关的。第三，考虑了从PU到SU的干扰以及从SU到PU的干扰。为了调查SU的中断性能，获得SU信号与干扰噪声比的累积分布函数的封闭式表达式，然后将其用于导出用于评估二次系统中断性能的表达式。通过计算机仿真验证的数值评估结果可提供有关各种实际情况下系统中断性能对空间天线相关性和PU对SU的影响的见解。