UFMC-MIMO系统中一种干扰消除算法

An Interference Cancellation Algorithm in UFMC-MIMO System

通用滤波多载波(UFMC)作为5G最具潜力的候选波形之一,它的优势在于比正交频分复用(OFDM)具有更低的带外泄露,且发送时不需要添加循环前缀(CP),还能与多输入多输出(MIMO)系统良好地兼容。然而现有对UFMC的研究多数停留在单输入单输出(SISO)系统,已不能满足5G及未来通信系统的需要,因此对UFMC-MIMO系统的研究具有重要意义。本文提出一种利用Walsh码设计的特殊训练结构对UFMC-MIMO系统进行定时同步的算法,首先对各信道进行定时同步,再对经过定时同步后的信号作频偏估计得到各发送天线与接收天线的频偏估计值,最后在时域对信号进行频偏补偿,从而达到降低或消除定时频偏对信号传输的影响。本文基于2×2的UFMC-MIMO系统进行仿真,结果表明该算法能够有效降低信号误符号率和显著提升系统的抗干扰性能。

As one of the most promising candidate waveforms for 5G,universal filter multi-carrier(UFMC)has the advantage of lower out-of-band leakage than orthogonal frequency division multiplexing(OFDM),and does not need to add a cyclic prefix(CP).It is also well compatible with multiple-input multiple-output(MIMO)systems.However,most of the existing researches on UFMC are still in single-input-single-output(SISO)systems,which cannot meet the needs of 5G and future communication systems.Therefore,the research on UFMC-MIMO systems is of great significance.An algorithm of timing synchronization for UFMC-MIMO system is proposed in this paper,which uses a special training structure designed by Walsh codes.Firstly,timing synchronization is performed on each channel.Then the frequency offset estimation of the signal after timing synchronization is performed to obtain the frequency offset estimation of each transmitting antenna and receiving antenna.Finally,the signal is compensated in time domain to reduce or eliminate the effect of timing frequency offset on signal transmission.The simulation results based on a 2×2 UFMC-MIMO system show that the proposed algorithm can not only effectively reduce the symbol error rate,but also significantly improve the anti-interference performance of the system.