The core problem of cognitive radio networks is the accurate sensing and the efficient use of spectrum holes without interfering the communication of the primary system. This paper proposes a cooperative strategy with two full-duplex cognitive base stations (FDCBS) where in-band full-duplex technology and cognitive radio are integrated. If the primary channel is in the “busy” state, the FDCBS assist the primary system in the retransmission of the failed packet and receive the cognitive packets simultaneously. We derive the outage probability and the average spectral efficiency of the primary system and the cognitive system for two scenarios where the 2-state Discrete Markov Chain describes the primary system behaviour (2-SDMC) and a non-identically distributed Nakagami-m fading channel is assumed. We determine the average spectral efficiency of the cognitive system in the case of incomplete self-interference, and the lower bound of the outage probability of the cognitive system when the primary channel is in the “busy” state. Numerical results show that our proposed scheme achieves a better improvement on the efficiency of the cognitive system and the primary system simultaneously than the traditional Half-Duplex relay mode.

认知无线电网络的核心问题是在不干扰主系统通信的情况下准确感知和有效利用频谱空洞。本文提出了一种与两个全双工认知基站（FDCBS）合作的策略，其中带内全双工技术与认知无线电相集成。如果主信道处于“忙”状态，则FDCBS会辅助主系统重发失败的数据包并同时接收认知数据包。我们推导出中断概率和所述主系统的平均频谱效率和对两种情况认知系统，其中，2-状态离散马尔科夫链描述了主系统行为（2- SDMC）和非恒等分布Nakagami-米假设衰落信道。我们确定不完全自我干扰情况下认知系统的平均频谱效率，以及当主通道处于“繁忙”状态时认知系统中断概率的下限。数值结果表明，与传统的半双工中继模式相比，本文提出的方案在认知系统和主系统的效率上有更好的提高。