异步DS-CDMA系统的等效同步多用户检测算法

第三代移动通信系统中，多用户检测技术是克服多址干扰(MAI)、增加系统容量的有效方法。本文针对多径衰落信道下的直扩码分多址(DS—CDMA)系统的上行链路，基于等效扩频码组Gram—Schmitz正交化与串行干扰消除(SIC)，提出了等效同步多用户检测(ESMUD)算法。分析最大比合并瑞克(RAKE)接收算法、传统的SIC算法以及本文算法的复杂度，并对三种算法的性能进行数值仿真。结果表明，本文提出的算法能有效抑制MAI，且计算复杂度与传统SIC算法在同一量级上。     

异步DS-CDMA系统中的盲联合干扰消除与多用户检测

针对异步DS-CDMA系统存在强恶意干扰时,系统性能急剧下降的问题。本文提出一种采用双天线接收的盲联合干扰消除与多用户检测方案。不同于传统的多用户检测方法,该方案考虑了恶意干扰的影响,首先通过串并变换将恶意 干扰等效为多路信号,然后利用双天线接收到的两路受扰信号构造超定或适定盲源分离模型,将干扰消除与多用户检测问题转化为一相关源的盲分离问题,最后利用基于最大非高斯性盲源分离算法进行分离,从而实现盲联合干扰消除与多用户检测。该方案可以在未知扩频序列以及信道信息的情况下完成多用户检测,同时实现恶意干扰的消除,提高了系统的抗干扰能力。仿真结果表明该方案对单音干扰、部分频带干扰以及扫频干扰均具有一定的鲁棒性。      

一种改进的分立式自适应多用户检测器的研究

多址干扰引发严重的远近问题。本文以分立式自适应多用户检测器为基础，将最大似然准则应用其中，得到改进得多用户检测器。分析和仿真结果表明，该类自适应多用户检测器具有更好的收敛速度和较为简单的结构，具有广泛的应用前景。     

宽带在移动通信系统中应用的关键技术

宽带CDMA是第三代移动通信系统IMT-2000的核心技术,探讨宽带在移动通信系统中应用的关键技术.     

直扩码分多址个人通信系统在衰落信道中的多用户信号检测

本文在ＤＳ－ＣＤＭＡ ＰＣＮ系统抗干扰性能的分析中，首次提出了用户归一化扩频信号等效左半部分和等效右半部分的分析模型，并在此基础上有效地结合传统扩频通信ＲＡＫＥ接收机的抗多径性能和多用户信号检测器的抗多址干扰特性，得到了一种能同时消除同频干扰和对抗多径多用户信号检测新方法。     

基于卷积小波包变换的自适应多用户检测

为提高DS-CDMA多用户系统检测的效率,提出了基于卷积小波包变换的自适应算法。理论分析和仿真结果表明,该算法收敛速度快,且计算量增加较少,是一种高效的自适应检测算法。     

An Adaptive MMOE-PIC Detector for Asynchronous DS-CDMA Communications

We propose a modified linear parallel interference cancelation (PIC) structure using the adaptive minimum mean output-energy (MMOE) algorithm for direct-sequence code-division multiple-access (DS-CDMA) systems. The complexity of the proposed receiver structure is shown to be linear in the number of users and hence, lower complexity than the centralized minimum mean-squared error (MMSE) multiuser detector. It is demonstrated that the proposed receiver structure can significantly reduce the long training period required by the standard adaptive MMOE receiver in near-far environments. Both numerical and theoretical results show that the proposed receiver performs close to the optimum MMSE receiver whereas the conventional adaptive MMOE detector suffers from high BER’s due to the imperfect filter coefficients. Also our results show a three fold increase in the number of users when the MMOE-PIC is used relative to the conventional MMOE receiver. Furthermore, the transient behavior of the proposed MMOE-PIC receiver due to abrupt changes in the interference level is examined. It is shown that the proposed adaptive receiver offers much faster self recovery, with less signal-to-interference ratio (SIR) degradation, than the standard MMOE in sever near-far scenarios.     

基于SMO算法的多用户检测技术

由于支持向量机的出色的学习性能，它已成为继神经网络之后新的研究热点，并在很多领域得到了成功的应用。本文提出了一种基于支持向量机多用户检测器，并采用顺序最小优化（SMO）算法构建了多用户检测器。计算机仿真的结果表明，该检测器的抗误码性能和抗远近效应性能都优于传统的多用户检测器。     

A New Improved First-Order Approximate Decorrelating Detector for DS-CDMA Communication Systems

An improved first-order approximate decorrelating detector for direct-sequencecode divisionmultiple access (DS-CDMA) communication systems is proposed. This detector isbased on theminimization of the multiple access interference (MAI) for each user. Throughanalysis andnumerical results, the detector is shown to perform better than the originalfirst-order approximatedetector in various conditions at the expense of an additional complexity onthe order of O(K²), whereK is the number of active users in the system.     

DS-CDMA卫星通信系统线性多用户检测算法性能比较

CDMA是新一代移动通信系统的关键技术,现代卫星移动通信也采用CDMA技术。多址干扰(MAI)的存在严重影响了CDMA系统的性能,需要采用多用户检测技术进行抑制。本文分析了卫星移动通信系统的模型,将线性多用户检测算法用于卫星移动通信系统,并对传统检测器、解相关检测器、MMSE检测器等线性检测器进行了性能比较。计算机仿真结果表明采用线性多用户检测技术使卫星移动通信系统的性能得到了明显的改善。     

Multi-user detection scheme for SCMA systems based on iteration removal

A multi-user detection scheme based on iteration removal (RM-MPA) was proposed to solve the problem of high complexity of decoding algorithm for sparse code multiple access (SCMA) systems.Firstly,a simple and novel method to compare the decoding advantages between users was proposed.Then n users in front of them with higher decoding advantages directly decoded and removed after each iteration,the users removed no longer participate in the subsequent iteration,so the complexity of subsequent iterations decreased gradually.Moreover,two iteration removed strategies based on decoding advantages of users and orthogonal user grouped were proposed respectively.Simulation results show that the RM-MPA with removed strategies based on orthogonal user grouped,which can reduce the decoding complexity with well decoding performance,and the decoding delay is also decreased.     

CDMA系统中基于噪声ICA的多用户检测方法

将独立分量分析方法应用于CDMA系统的多用户检测中,针对ICA噪声模型,对噪声分量进行分析,根据修正的牛顿迭代法对ICA算法进行改进,提出一种改进的多用户检测方法。仿真结果表明,改进的噪声ICA多用户检测方法有效地降低了误码率,提高了检测性能。     

Near-Optimum Iterative Multiuser Receiver for FEC Encoded DS-CDMA

The powerful iterative algorithm of Turbo code is employed in the proposed iterative multiuser receiver for the downlink of a forward error correction (FEC) coded direct-sequence code-division multiple access (DS-CDMA) environment. The receiver iterates between the 2 coding dimensions, namely the spreading codes and the FEC codes. The optimum iterative multiuser receiver uses the optimum decentralised single-user detector to generate the single-user extrinsic information for the single-user decoders. This paper suggests a near-optimum detector using a folded trellis preselection stage for the multiuser signal detection, in order to reduce the dominating complexity of the optimum decentralised detector. Simulation results show that performance is close to optimum. The effect of the single-user decoders' extrinsic information on the signal detection stage is also investigated and it is found that extrinsic information improves performance.     

基于OCDMA over WDMA光纤网络

基于OCDMA(optic code division multiple access)在网络扩张方面的优势,考虑采用相干OCDMA方法提出了OCDMA over WDMA(wavelength division multiple access)光网的结构,并对其网络特性、连接协议、优点及其在光网络中应用时系统出现的问题加以讨论.最后通过计算机仿真,研究了OCDMA overWDMA网络的阻塞特性与时间延迟.     

随机码多业务直扩系统的RAKE接收机在Nakagami信道下的性能

本文提出用RAKE接收机的可变处理增益系统,通过高斯近似,得出了各种业务在不同的概率的情况下,可变处理增益系统在Nakagami信道下误码率的计算公式,研究了衰落因子对系统的影响,最后,给出了两种业务,三种业务可变处理增益系统数值计算结果。     

数字移动通信的发展趋向和关键技术

数字化是移动通信发展的必然趋势。数字通信的发展为个人通信奠定了技术基础，并将最终向个人通信方向发展，个人通信目的实现为数字移动通信的发展起着促进和推动作用。本文讨论了数字移动通信的发展趋向以及关键技术。     

一种基于一阶扰动自适应特征值分解的多用户检测算法

本文提出了一种新的、适用于多径信道中多用户检测的盲自适应算法.这种算法使用基于一阶扰动的自适应特征值分解算法对信号空间进行分解,并使用最小均方(LMS)算法对信道进行盲自适应估计.实验和仿真证明,这种算法收敛速度快,稳态性能好,是一种较好的盲自适应多用户检测算法.     

无线多媒体DS—CDMA系统中的功率分配算法研究

本文提出一种基于信道特征（如业务量）的功率分配算法,并通过系统分析验证了该算法是能很好地在保证各业务的业务质量同时提高系统的容量。     

CDMA2000移动通信系统的技术特点和展望

介绍了CDMA2000系统的物理信道,给出了CDMA2000核心网络的特点、基于IS-95的第3代移动通信移动的演进策略及对CDMA2000系统的展望。     

直扩系统GSC接收机的性能研究

提出了用GSC接收机的可变处理增益系统,并分析了各种可能业务在不同的概率的情况下,双速率及三速率可变处理增益系统在Nakagami信道下的性能。