摘要
如果采用现有认知无线电系统方案，那么认知用户（cognitive user，CU）使用电视频带会面临电视信号干扰问题．为此，提出一种基于原模图LDPC码的电视频带认知无线电系统干扰抑制方法．将原模图LDPC码与虚拟MIMO应用到认知无线电系统中，通过对发送数据流的信道编码与MIMO空时处理来抑制电视信号干扰和噪声干扰．其核心是利用认知用户问信道衰减与电视台发射机和认知用户之间信道衰减的差异，在认知用户接收端将电视信号和信道噪声视为新的噪声．通过原模图LDPC码译码，可以使认知用户接收端抑制电视信号干扰．在理想情况下，所提出的电视频带认知MIMO系统方案能够增加通信容量约O．62—0．76倍．仿真分析表明，在瑞利平坦衰落信道，所提方案与直接方法相比可得到约12dB的编码增益，并能有效抑制电视信号干扰．
In TV band, adopting the current cognitive radio schemes, the cognitive user （CU） will face the problem of TV signals. In order to solve this problem, this paper proposes a novel interference cancellation scheme based on protograph LDPC codes and virtual MIMO for cognitive radio system in television band. Protograph LDPC codes are applied to virtual MIMO cognitive radio system in the proposed scheme, and by encoding transmitting data and MIMO space-time processing, it can cancel TV signal interference and channel noise. The core idea of the proposed scheme is that, depending on the difference of channel fading between the CUs and TV station＇s transmitter, the TV signal interference and channel noise are looked as a new interference at the CU receiver. By decoding received signal using protograph LDPC, the CU receiver can cancel the TV signal interference from the TV station. In an optimal situation, the proposed approach can increase about 0.62-0.76 times of communication capacity for the proposed cognitive radio system. Comparing with the approach of directly extracting user information, the proposed scheme obtained about 12 dB coding gain in Rayleigh flat-fading channel, and it can cancel the TV signal interference efficiently.
出处
《应用科学学报》
CAS
CSCD
北大核心
2014年第3期237-245,共9页
Journal of Applied Sciences
基金
北京市自然科学基金(No.4102050)资助
