基于部分FFT-WFRFT的高效MMSE波束成形算法

High efficiency MMSE Beamforming Algorithm Based on partial FFT Demodulation in Hybrid Carrier Communication

摘要:

摘要：现代无线通信环境下多种干扰同时存在造成通信过程受到多种干扰的影响。高速运动环境中，收发两端相对运动产生较大的多普勒频移进而产生时间选择性衰落，同时，由于多径的影响，会造成多条路径之间到达接收端的延迟不同进而产生频率选择行衰落。时频双选信道中，多径干扰产生的ISI和多普勒效应产生的ICI往往同时存在，传统的通信系统设计中，往往只针对一个方面进行考虑，不能满足现代复杂通信环境中通信的需求。针对现代无线通信系统的这种时频抗干扰的需求，研究了基于四项加权分数傅里叶变换的混合载波系统，同时，考虑系统的抗干扰能力有限，提出了混合载波系统中的部分FFT-WFRFT的高效MMSE波束成形算法，通过特殊的导频结构设计，在多径时延长度小于信号长度一半时，即使多径时延的长度小于循环前缀的长度仍能够满足通信需求，提高了系统的传输效率。通过仿真本算法信号的传输效率提高了2.7%，在多径时延更严重的情况下传输效率甚至可以提高5%左右。

Abstract:

Abstract：In modern complex communication environment, both the time interference and frequency interference cannot be ignored in the wireless communication channels. In the condition of high speed environment, large Doppler offset appears because of the relative motion between the transmitter and the receiver. Besides, as a result of being reverberation diffraction and scattering, signals may arrive at the receiver from some different paths. In this paper hybrid carrier (HC) system based on 4-WFRFT is designed which is proved to be having a better performance in time-frequency channels. In addition, partial FFT modulation beamforming algorithm is used to improve transmission efficiency, with a special pilot, the communication system can get a better performance even the length of the cyclic prefix is shorter than the time-delay. In this paper 2.7% are promoted with the algorithm proposed. When the time spreading is worse, the promotion can even reach 5%.