基于正交叠加的SCMA系统信道估计方法  

Channel estimation method of SCMA system based on orthogonal superposition

作　　者：李啸天 季雪京 马金龙 Li Xiaotian;Ji Xuejing;Ma Jinlong(School of Information Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China)

机构地区：[1]河北科技大学信息科学与工程学院,石家庄050018

出　　处：《电子测量技术》2024年第19期9-16,共8页Electronic Measurement Technology

基　　金：河北省省级科技计划项目(23550801D)资助。

摘　　要：在稀疏码分多址接入(SCMA)系统中,由于相同子载波上叠加多个用户数据,且不同用户的信道条件不同,所以无法直接进行准确的信道估计。针对此问题,提出了一种基于正交叠加的SCMA系统信道估计方法。该方法利用SCMA系统码本的稀疏性,设计了一种多用户时隙复用的新型导频结构,使不同用户的导频数据在相同时隙叠加后仍能够保证子载波资源相互正交,同时降低了导频资源时隙开销。在此基础上进一步提出了局部正交叠加的导频结构,利用子载波间相关性估计相邻子载波的信道衰落系数,进一步降低导频资源时隙开销。仿真结果表明:在总时间开销相同的前提下,正交叠加方法的信道估计均方误差性能相比于现有方法提升了3 dB,局部正交叠加性能进一步提升了1.7 dB。In sparse code division multiple access(SCMA)systems,because multiple user data are superimposed on the same subcarrier and the channel conditions of different users are different,accurate channel estimation cannot be performed directly.To solve this problem,a channel estimation method for SCMA systems based on orthogonal superposition is proposed.This method uses the sparsity of SCMA codebook to design a new pilot structure with multi-user timeslot multiplexing,which can ensure the orthogonal subcarrier resources and reduce the timeslot overhead of pilot resources after the same timeslot is superimposed on the pilot data of different users.On this basis,a pilot structure of local orthogonal superposition is proposed,and the channel fading coefficients of adjacent subcarriers are estimated by using the correlation between subcarriers to further reduce the time slot overhead of pilot resources.The simulation results show that the channel estimation MSE performance of orthogonal superposition method is improved by 3 dB and the local orthogonal superposition performance is further improved by 1.7 dB compared with the traditional method under the same total time cost.

关 键 词：稀疏码分多址接入 正交叠加 信道估计 导频结构 时隙开销 均方误差 

分 类 号：TN92[电子电信—通信与信息系统]