基于OGCE⁃BEM的OTFS信道估计  

OTFS Channel Estimation based on OGCE⁃BEM

作　　者：李心怡 解志斌[1] 张金波 毛云龙 LI Xinyi;XIE Zhibin;ZHANG Jinbo;MAO Yunlong(Ocean College,Jiangsu University of Science and Technology,Zhenjiang 212003,China)

机构地区：[1]江苏科技大学海洋学院,江苏镇江212003

出　　处：《光通信研究》2024年第3期147-152,共6页Study on Optical Communications

基　　金：国家自然科学基金资助项目(62276117);江苏省未来网络科研基金资助项目(FNSRFP⁃2021⁃YB⁃51)。

摘　　要：【目的】随着面向第六代移动通信技术研究工作的开展,传统的正交频分复用(OFDM)系统中的载波间干扰使得信道估计性能不足以提供高度可靠的通信,而正交时频空(OTFS)系统可以有效解决快速时变性和多普勒效应导致的通信系统可靠性下降问题,近年来受到了广泛关注。【方法】为了有效满足OTFS系统所需的信道估计性能需求,文章采用优化的广义复指数(OGCE)基扩展模型(BEM)将信道脉冲响应建模为时不变的基函数与基函数系数的形式,从而有效地拟合高速移动通信场景下的快速时变信道。OGCE⁃BEM通过更加密集的采样改善了频谱泄漏的问题,并且通过增加修正系数降低了高频基模型的误差。为了得到更为精确的基函数系数,文章基于遗忘因子与估计误差的关系,设计了可变遗忘因子的递归最小二乘(RLS)滤波器,使得RLS滤波器可以实时追踪基函数系数的变化。【结果】仿真结果表明,文章所提算法适用于高速移动通信场景,基函数的设计更为合理,相较于固定遗忘因子的估计方法,具有更低的均方误差,信道估计结果更加精确。与最小二乘(LS)、BEM⁃LS和BEM⁃线性最小均方差(LMMSE)信道估计方式相比,均方误差性能得到了明显提升。【结论】文章所提基于OGCE⁃BEM的信道估计算法有效减少了待估计未知参数量,提高了信道估计的准确性。【Objective】With the development of the sixth generation mobile communication technology,the inter⁃carrier interfer ence in the traditional Orthogonal Frequency Division Multiplexing(OFDM)system makes the channel estimation performance insufficient to provide highly reliable communication,and Orthogonal Time⁃Frequency Space(OTFS)system can effectively solve the problem of communication system reliability degradation caused by fast time variability and Doppler effect,which has re ceived wide attention in recent years.【Methods】In order to effectively meet the channel estimation performance requirements of OTFS systems,this paper uses an Optimized Generalized Complex Exponential(OGCE)Basis Expansion Model(BEM)to cal culate the channel impulse response as a time⁃invariant basis function with basis function coefficients,which can effectively fit fast time⁃varying channels in high⁃speed mobile communication scenarios.The OGCE⁃BEM improves the spectral leakage by more intensive sampling and reduces the error of the high⁃frequency basis model by adding correction coefficients to reduce the error of the HF⁃based model.【Results】The simulation results show that the proposed algorithm is suitable for high⁃speed mobile commu nication scenarios with more reasonable design of the basis function.The estimation method has lower mean square error than the fixed forgetting factor,and the channel estimation results are more accurate.Compared with Least Square(LS),BEM⁃LS and BEM⁃Linear Minimum Mean Square Error(LMMSE)channel estimation methods,the performance of mean square error is sig nificantly improved.【Conclusion】It can be seen that the channel estimation algorithm based on OGCE⁃BEM can effectively re duce the number of unknown parameters to be estimated and improve the accuracy of channel estimation.

关 键 词：正交时频空 优化的广义复指数基扩展模型 遗忘因子 信道估计 

分 类 号：TN911[电子电信—通信与信息系统]