In this paper, we investigate multi-antenna interference rejection combing (IRC)-based black-space cognitive radio (BS-CR) operation in time-varying channels. The idea of BS-CR is to transmit secondary user (SU) signal in the same frequency band with the primary user (PU) such that SU’s power spectral density is clearly below that of the PU, and no significant interference is inflicted on the PU receivers. We explore the effects of interpolation and mobility on the novel blind IRC technique which allows such operation mode for effective reuse of the PU spectrum for relatively short-distance CR communication. We assume that both the PU system and the BS-CR use orthogonal frequency division multiplexing (OFDM) waveforms with common numerology. In this case, the PU interference on the BS-CR signal is strictly flat-fading at subcarrier level. Sample covariance matrix-based IRC adaptation is applied during silent gaps in CR operation. We evaluate the effect of the gap length on the link performance, using known PU channel-based interference covariance estimation as reference. We also propose an interpolation-based scheme for tracking the spatial covariance in time-varying channels, demonstrating significantly improved robustness compared to the earlier scheme. The performance of the proposed IRC scheme is tested considering terrestrial digital TV broadcasting (DVB-T) as the primary service. Also joint PU and co-channel CR interference cancellation is included in the study. The resulting interference suppression capability is evaluated with different PU interference power levels, silent gap durations, data block lengths, and CR device mobilities.

在本文中，我们研究时变信道中基于多天线干扰抑制梳（IRC）的黑空间认知无线电（BS-CR）操作。BS-CR的想法是在与主要用户（PU）相同的频带中传输次要用户（SU）信号，以使SU的功率谱密度明显低于PU的功率谱密度，并且不会对PU造成重大干扰接收者。我们探索内插和迁移率对新型盲IRC技术的影响，该技术允许这种操作模式有效地重用PU频谱以用于相对短距离的CR通信。我们假设PU系统和BS-CR都使用具有共同数字学的正交频分复用（OFDM）波形。在这种情况下，BS-CR信号上的PU干扰在子载波级别上严格平淡化。基于样本协方差矩阵的IRC自适应应用于CR操作中的无声间隙。我们使用已知的基于PU信道的干扰协方差估计作为参考，评估间隙长度对链路性能的影响。我们还提出了一种基于插值的方案来跟踪时变信道中的空间协方差，与早期方案相比，证明了鲁棒性显着提高。以地面数字电视广播（DVB-T）为主要服务，对提议的IRC方案的性能进行了测试。该研究还包括联合PU和同信道CR干扰消除。使用不同的PU干扰功率电平，静默间隙持续时间，数据块长度和CR设备迁移率评估产生的干扰抑制能力。