Achievable Rate of Spectrum Sharing Cognitive Radio Multiple-Antenna Channels
Achievable Rate of Spectrum Sharing Cognitive Radio Multiple-Antenna Channels
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DOI：
10.1109/twc.2015.2427281
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发表时间：
2015-04
影响因子：
10.4
通讯作者：
Lokman Sboui;Hakim Ghazzai;Z. Rezki;Mohamed-Slim Alouini
中科院分区：
文献类型：
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作者：
Lokman Sboui;Hakim Ghazzai;Z. Rezki;Mohamed-Slim Alouini
研究了认知无线电上行链路多输入多输出系统的频谱效率增益，在该系统中，次用户(SU)被允许使用特定的预编码方案与主用户(PU)共享频谱以与公共接收机通信。该方案同时利用了空间对准过程后主信道的自由本征模和PU所能容忍的干扰门限。在公共接收端，我们采用连续干扰消除(SIC)技术来消除被检测的一次信号通过所利用的本征模式传输的影响。此外，我们还分析了SIC运算的不准确性以及CSI对PU和SU吞吐量的估计缺陷。数值结果表明，我们提出的方案显著提高了认知可达速率。例如，在完美检测PU信号的情况下，对于高信噪比，CR率保持非零，当我们仅使用空间对准技术时，这通常是不可能的。结果表明，在PU处采用改进的充水功率分配策略可以提高二次速率，但对主速率的影响不大。最后，我们通过对速率可达区域的研究，研究了PU和SU速率的行为。
We investigate the spectral efficiency gain of an uplink cognitive radio (CR) multi-input-multi-output system in which the secondary user (SU) is allowed to share the spectrum with the primary user (PU) using a specific precoding scheme to communicate with a common receiver. The proposed scheme exploits, at the same time, the free eigenmodes of the primary channel after a space alignment procedure and the interference threshold tolerated by the PU. At the common receiver, we adopt a successive interference cancellation (SIC) technique to eliminate the effect of the detected primary signal transmitted through the exploited eigenmodes. Furthermore, we analyze the SIC operation inaccuracy as well as the CSI estimation imperfection on the PU and SU throughputs. Numerical results show that our proposed scheme enhances considerably the cognitive achievable rate. For instance, in case of a perfect detection of the PU signal, the CR rate remains non-zero for high signal to noise ratio, which is usually impossible when we only employ a space alignment technique. We show that a modified water-filling power allocation policy at the PU can increase the secondary rate with a marginal degradation of the primary rate. Finally, we investigate the behavior of the PU and SU rates through the study of the rate achievable region.