非对称成对载波多址信号的相位误差分析及幅度改进算法

针对由主站和小站信号同频混合而成的非对称成对载波多址（PCMA）信号解调问题，构建了一种实现此类信号解调的框架。参数估计是非对称PCMA通信系统在实现两路信号分离解调时不可或缺的环节，对于幅度参数估计精度问题，提出一种基于四次方法的搜索式幅度估计算法。首先建立非对称PCMA系统解调模型并作出基本假设，然后对不同假设下的相位误差进行对比并分析相位误差对幅度估计算法的影响，最后提出一种新的幅度估计算法。实验结果表明在相同信噪比（SNR）下，正态相位误差下的小站信号解调性能要劣于其均值条件下的解调性能。当误比特率（BER）在数量级为10^-4时，改进算法下小站信号的解调性能提升了1 dB，说明改进算法优于四次方法。     

基于CHASE译码思想的PCMA信号盲分离算法

在软输出逐幸存路径处理（SOVA-PSP）算法的基础上,提出了基于Chase译码思想的载波成对复用多址（PCMA）信号的盲分离算法。该算法对SOVA-PSP软输出的结果进行可靠性排序,对于排序中可靠性较低的混合符号进行信号重构,通过重构信号和接收信号之间的欧式距离对比纠正其中的错误结果。仿真结果表明,所提算法与SOVA-PSP算法相比,性能有2 dB左右的增益。     

基于单路定时准确的低复杂度成对载波复用多址信号盲分离算法

该文分析了传统逐幸存路径处理(Per-Survivor Processing,PSP)算法模型,给出了改进的前馈非二元码软输出维特比(Soft Output Viterbi Algorithm,SOVA)PSP算法。针对单路定时准确的情况,提出了针对成对载波复用多址(Paired Carrier Multiple Access,PCMA)信号的SOVA-PSP盲分离算法。该算法相对传统的PSP算法状态数由原来的2(L1)M-减少到(L1)M-(其中M为调制阶数,L为等效信道响应长度),从而大幅度地降低了算法复杂度。仿真结果表明,改进的算法在降低复杂度的同时与传统PSP算法相比性能几乎没有损失。     

PCMA系统中位定时误差对干扰抵消性能的影响

首先介绍了PCMA技术的基本概念 ,并建立了PCMA系统基带传输模型 ;在此基础上研究了PCMA系统中位同步误差对干扰抵消性能的影响 ,并给出了相应的仿真结果。根据系统对干扰抑制比的要求 ,仿真结果可以为位定时估计算法的设计提供可靠的依据     

Blind separation algorithm of PCMA signals with different symbol rates based on DG-PSP

A blind separation algorithm was proposed for PCMA signals with different symbol rates based on double grid per-survivor processing (DG-PSP).The channel states and two input signal components were treated as two dynamic grids,receiving mixed-signal reconstructed by respectively iterative updating the two groups of grid status,thus achieving blind signal separation.The joint iterative decoding separation structure was focused,and a detailed analysis and comparison under different error estimation of parameters was shown.The complexity of the algorithm is similar to the traditional PSP algorithm.Simulation results show that,a gain of about 2 dB in signal-noise ratio can be obtained after the first iteration at a bit error rate of 10^?2,and a gain of nearly 3 dB in signal-noise ratio can be obtained after the second iteration.     

Joint estimation of interference frequency offset and time delay in PCMA system

For cooperative received high-order modulation PCMA (paired carrier multiple access) signals,joint estima-tion of frequency offset and time delay was proposed.The sequence samples stored locally were used as auxiliary data.Estimation of frequency offset and time delay was calculated by optimizing the objective function,which was obtained from the cross-correlation computation of the auxiliary data and mixed signal,and the optimized process was accom-plished by utilizing two-dimensional search.By setting the threshold of joint estimation,the calculated amount was greatly reduced.Modified Cramer-Rao bound (MCRB) of interference frequency offset and time delay was derived,which provided theoretical basis for performance of the proposed algorithm.Simulation results show that the algorithm has similar performance with existing algorithms,but its complexity is reduced by two-thirds.     

基于PSP及Kalman滤波的PCMA信号盲分离算法

提出了一种成对载波多址系统中信息序列和信道联合估计的算法。该算法在不具备任一协作通信方发送的信息序列的先验知识前提下从混合信号中解调出两路信息序列。该算法结合了逐幸存路径处理法无延迟的信道参数估计特性和Kalman滤波良好的估计性能。仿真实验表明,该算法具有良好的信道捕获与跟踪能力,且实现较好的符号序列估计性能。     

利用累积量和似然特征的卫星单-混信号调制识别算

针对卫星通信中常用调制信号和PCMA类混叠信号的调制识别问题,提出了一种利用高阶累积量和似然特征的识别算法.算法先对接收数据进行预处理,在此基础上提取4个高阶累积量特征和1个似然特征,构造一个树形分类器进行调制识别.算法不需要知晓信号的定时等先验信息,对收发载频存在的频差不敏感.仿真结果表明,算法在正常通信所需的载噪比下具有较高的正确识别率.     

PCMA卫星系统中信号抑制与同步技术

本文研究了卫星通信系统中应用PCMA(PairedCarrierMultipleAccess)技术后信号抑制的问题,提出了把RLS算法用于信号的抑制,利用相关技术实现了信号同步,并已通过计算机仿真。     

一种实现PCMA信号快速捕获的方法

提出了一种实现PCMA系统中本站返回信号快速捕获的方法。该方法首先根据通信卫星与地球站的几何位置关系粗略估计本站返回信号的到达时间,设计通用的捕获时间窗口减小延时搜索范围,以减小总的虚警和漏警代价;然后采用基于资源复用的匹配滤波捕获算法,以较少的硬件资源获得了较高的检测概率。