CRAHNs网络中基于大规模MIMO的波束形成技术的研究

发布时间：2019-06-20 01:06

【摘要】：近年来,CRAHNs网络因为其通信可靠性高的特点得到了广泛研究,但是它对信号的发送功率有一定要求且无法有效抑制多径效应,而大规模MIMO技术可以显著提高系统的能量效率和频谱效率。因此本文将大规模MIMO技术与CRAHNs网络相结合,对该系统中的波束形成技术作了深入的研究,包括波束形成发送和波束形成接收技术,主要解决系统中存在的多径衰落和多节点干扰问题,提高网络的通信性能并降低能量消耗。(1)宽带波束形成接收技术。将窄带波束形成的信号接收模型和准则推广到宽带,给出了宽带波束形成的处理方法和数学表达式,并针对常规的波束形成算法运用到天线阵旁瓣较高的缺点,提出了可以应用于宽带的旁瓣约束优化波束形成算法,并仿真出了波束响应图,验证了该算法可以有效增强期望信号,抑制干扰信号,并可以降低旁瓣波束响应值。(2)与OFDM相结合以对抗多径的波束形成接收技术。将波束形成技术与OFDM系统相结合,目标是对抗或利用多径。介绍了波束形成应用到OFDM系统中的两种实现结构,研究了常规的LMS-OFDM算法,针对该算法无法充分利用多径信号和抗干扰性弱的缺点,提出了MCMV-OFDM的新算法。仿真结果表明,该算法可以充分利用多径信号,降低多径系统的误码率。(3)多节点MIMO系统中以消除同信道干扰(CCI)的波束形成发送技术。给出了多节点MIMO系统的数学模型,学习了常规的在发射端消除CCI的波束形成方案,但是该算法对发送天线数目有一定要求。针对这一缺点,提出了以最大信漏比为准则的波束形成的新方法,该算法可以消除多节点间的干扰,且对发射天线数没有要求,仿真结果证实了该算法可以显著降低系统误码率。
[Abstract]:In recent years, CRAHNs network has been widely studied because of its high communication reliability, but it has certain requirements for signal transmission power and can not effectively suppress the multi-path effect. Large-scale MIMO technology can significantly improve the energy efficiency and spectral efficiency of the system. Therefore, combining large-scale MIMO technology with CRAHNs network, the beamforming technology in the system is deeply studied, including beamforming transmission and beamforming reception technology, which mainly solves the problems of multi-path fading and multi-node interference in the system, improves the communication performance of the network and reduces the energy consumption. (1) Broadband beamforming reception technology. The signal receiving model and criterion of narrowband beamforming are extended to broadband, and the processing method and mathematical expression of broadband beamforming are given. Aiming at the disadvantage that conventional beamforming algorithm is applied to antenna array with high sidelobe, a sidelobe constrained optimization beamforming algorithm which can be applied to broadband is proposed, and the beam response diagram is simulated, which verifies that the algorithm can effectively enhance the desired signal and suppress the interference signal. The response value of sidelobe beam can be reduced. (2) combined with OFDM to combat multi-path beamforming reception technology. Combining beamforming technology with OFDM system, the goal is to antagonize or utilize multi-path. This paper introduces two kinds of implementation structures of beamforming applied to OFDM system, studies the conventional LMS-OFDM algorithm, and puts forward a new algorithm of MCMV-OFDM in view of the fact that the algorithm can not make full use of multi-path signal and weak anti-interference. The simulation results show that the algorithm can make full use of the multi-path signal to reduce the bit error rate of the multi-path system. (3) beamforming transmission technology to eliminate co-channel interference (CCI) in the multi-node MIMO system. The mathematical model of multi-node MIMO system is given, and the conventional beamforming scheme to eliminate CCI at the transmitter is learned, but the algorithm has certain requirements for the number of transmit antennas. In order to solve this problem, a new beamforming method based on the maximum signal-leakage ratio is proposed. The algorithm can eliminate the interference between multiple nodes, and there is no requirement for the number of transmit antennas. The simulation results show that the algorithm can significantly reduce the bit error rate (BER) of the system.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3

【参考文献】