Performance Analysis of Uplink Massive Spatial Modulation MIMO Systems in Transmit-Correlated Rayleigh Channels

In this paper,the performance of uplink multiuser massive multiple-input multipleoutput(MIMO)system with spatial modulation over transmit-correlated Rayleigh fading channel is investigated,where a large number of antennas are deployed at the base station and linear zero-forcing(ZF)receiver is employed for detection.By taking the transmit correlation and the randomness of shadow fading in to account,the bit error rate(BER)performance of the system is analyzed.According to the performance analysis,an approximated expression of overall average BER of the system is attained.Besides,asymptotic performance is studied and the corresponding BER expression at high signal-to-noise ratio is derived.On this basis,the diversity gain of the system can be obtained for performance evaluation.Simulation results show that the derived theoretical expressions match the simulated values well,which verifies the correctness of our analysis.     

Performance Evaluation of Combined Coding and Modulation Schemes for Nonlinear Channels

The performance of combined coding and modulation schemes in channels with intersymbol interference and nonlinearities is studied using an analytical approach. The class of possible receivers is presented, and a generalization of the minimum Euclidean distance used for the asymptotic analysis of the performance of combined coding and modulation schemes on AWGN channels is introduced. Numerical results are presented for coded 16-PSK modulation.     

Performance Analysis of LDPC-Coded Space-Time Modulation over MIMO Fading Channels

A closed-form upper bound on the error performance is proposed for LDPC-coded space-time modulation over MIMO block/slow fading channels based on the analysis framework developed for the fast fading case. This follows from the observation that the pairwise error probability (PEP) in all these fading cases is determined by a certain metric of codewords, with respect to which we can enumerate all distinct PEPs and thus concisely formulate the union bound. Simulation results indicate that the bound is useful to benchmark the performance of iterative decoding and detection algorithms     

Performance of VBLAST Systems Based on Spatial Correlated MIMO Channels

1　Introduction　Recentinformationtheoryresultshaveshowntheenormouscapacitypotentialofwirelesscommunica tionsystemswithantennaarraysatboththetrans mitterandreceiver[1～ 3] .TheVBLASTarchitec ture[4～ 5] isonesuchapproach .VBLASTsystemstransmitparalleldatastreams,usingmultipleanten nas,simultaneouslyandinthesamefrequencyband .Withrichmultipathpropagation ,thesedif ferentstreamscanbeseparatedatthereceiverbe causeoftheirdistinctspatialsignatures.Inaflat fadingscatteringenvironmentwithindepen…     

Blind Schemes for Asynchronous CDMA Systems on Dispersive MIMO Channels

The problem of blind detection in a dispersive multiple-input multiple-output (MIMO) code division multiple access (CDMA) channel is considered in this paper. Unlike previous studies, each user is assigned one spreading code to be employed on all of the transmit antennas, which poses a problem of data re-association at the receiver-end in the absence of prior information as to the channel state. Focusing on the differential Alamouti scheme, we propose a two-stage receive structure. The first stage performs a linear interference-blocking transformation, which allows user separation and inter-symbol interference (ISI) suppression. The second stage is, instead, a novel differential space-time block (STB) decoder suitable for frequency-selective channels. Interestingly, the proposed detector allows decoupling of the decisions on the transmitted symbols, while its blind implementation only requires a cubic (in the processing gain) complexity. A thorough performance assessment is undertaken to investigate, on one hand, the capability of acquiring the missing information, such as the system and the encoder timings, on the other hand, the interplay between the diversity gain provided by the MIMO structure of the communication system, and the additional co-channel interference that multiple transmit antennas produce in multi-path, multiple-access channels.     

On the Performance of Golden Space-Time Trellis Coded Modulation over MIMO Block Fading Channels

The Golden space-time trellis coded modulation (GST-TCM) scheme was proposed in [1] for a high rate 2 × 2 multiple-input multiple-output (MIMO) system over slow fading channels. In this letter, we present the performance analysis of GST-TCM over block fading channels, where the channel matrix is constant over a fraction of the codeword length and varies from one fraction to another, independently. In practice, it is not useful to design such codes for specific block fading channel parameters and a robust solution is preferable. We then show both analytically and by simulation that the GST-TCM designed for slow fading channels are indeed robust to all block fading channel conditions.     

Average SER Performance of Distributed Antenna Systems Over Shadowed Generalized-Gamma Channels for Different Modulation Schemes

Recently, much attention has been drawn to distributed antenna systems (DAS), which are proposed to improve the performance of mobile communication systems. This paper focuses on the analysis of the average symbol error rate (SER) of DAS over a generic composite channel. Initially, a new composite channel model is considered for DAS, which is a mixture of path loss, lognormal shadowing and generalized-Gamma fast fading. This composite channel model is a generic model, which includes many well-known composite channel models as special cases. Based on the channel model, the cumulative distribution function of the output signal-to-noise ratio is obtained by employing selective transmission scheme. Moreover, by averaging the channel conditions and the positions of the MS in the cell, an approximate expression of the average SER is derived, which is a unified form of expression for many commonly used modulation schemes. Numerical results show that the derived expression of the average SER can provide sufficient precision for evaluating the SER performance of DAS under different modulation schemes.     

FEC编码的空间调制方案综述

空间调制系统作为多输入多输出技术(Multi-input Multi-output,MIMO)的一种,优点是在减少多天线方案的复杂度和成本的同时,始终能够保证较高的数据传输速率。在每个信道使用间隙下,仅使用一根选定的天线(称为活动天线)发送数据信号,并且活动天线空间位置作为数据传输的附加维度。然而,空间调制技术的分析和设计依然面临许多挑战,编码空间调制方案就是其中一种。针对编码空间调制方案,重点论述了Trellis码、BMST码、LDPC码以及多元LDPC码等信道编码空间调制方案,并且分析了这几种方案的特点以及它们在MIMO中的应用。     

HOS-Based Semi-Blind Spatial Equalization for MIMO Rayleigh Fading Channels

In this paper, we concentrate on the direct semi-blind spatial equalizer design for MIMO systems with Rayleigh fading channels. Our aim is to develop an algorithm which can outperform the classical training-based method with the same training information used and avoid the problems of low convergence speed and local minima due to pure blind methods. A general semi-blind cost function is first constructed which incorporates both the training information from the known data and some kind of higher order statistics (HOS) from the unknown sequence. Then, based on the developed cost function, we propose two semi-blind iterative and adaptive algorithms to find the desired spatial equalizer. To further improve the performance and convergence speed of the proposed adaptive method, we propose a technique to find the optimal choice of step size. Simulation results demonstrate the performance of the proposed algorithms and comparable schemes.     

Transmit Antenna Selection Schemes for Quadrature Spatial Modulation

The objective of this paper is to investigate the application of transmit antenna selection (TAS) to quadrature spatial modulation (QSM). The application of optimal Euclidean distance based antenna selection (EDAS) to QSM (EDAS-QSM) is first proposed. EDAS-QSM requires an exhaustive search, which imposes a significantly high computational complexity. In this regard, a reduced-complexity algorithm for the computation of EDAS-QSM is proposed. Finally, several low-complexity, sub-optimal TAS techniques for QSM are investigated. The decision metrics of these schemes are based on channel amplitude, antenna correlation, Euclidean distance or a combination thereof. Monte Carlo simulation results demonstrate the effectiveness of the proposed schemes, while the computational complexity of each is analysed. The trade-off between error performance and computational complexity is discussed for each of the schemes.     

Average Error Performance of M-ary Modulation Schemes in Nakagami-q (Hoyt) Fading Channels

Presented are exact-form expressions for the average error performance of various coherent, differentially coherent, and noncoherent modulation schemes in Nakagami-q (Hoyt) fading channels. The expressions are given in terms of the Lauricella hypergeometric function, F_D ⁽ⁿ⁾; for nges1, which can be evaluated numerically using its integral or converging series representation. It is shown that the derived expressions reduce to some existing results for Rayleigh fading as special cases     

Redesigned Spatial Modulation for Spatially Correlated Fading Channels

In this paper, a new variant of Spatial Modulation (SM) Multiple-Input Multiple-Output (MIMO) transmission technique, designated as Redesigned Spatial Modulation (ReSM) has been proposed. In ReSM scheme, a dynamic mapping for antenna selection is adopted. This scheme employs both single antenna as well as double antenna combinations depending upon channel conditions to combat the effect of spatial correlation. When evaluated over spatially correlated channel conditions, for a fixed spectral efficiency and number of transmit antennas, ReSM exhibits performance improvement of at least 3 dB over all the conventional SM schemes including Trellis Coded Spatial Modulation (TCSM) scheme. Furthermore, a closed form expression for the upper bound on Pairwise Error Probability (PEP) for ReSM has been derived. This has been used to calculate the upper bound for the Average Bit Error Probability (ABEP) for spatially correlated channels. The results of Monte Carlo simulations are in good agreement with the predictions made by analytical results. The relative gains of all the comparison plots in the paper are specified at an ABER of 10^?4.     

Simplified 3D Fading Channels Adopted in MIMO Beamforming Schemes

A simplified three-dimension (3D) fading channel model deployed in a multi-input multi-output (MIMO) beamforming system is explored in this article. Both angle of arrival (AoA) and angle of departure (...     

DSSS通信系统中干扰环境下码捕获 和阵列权值联合捕获

提出了空时相关器(STC)方法,同时实现干扰环境下使用自适应阵列的直接序列扩谱(DSSS)通信系统的码捕获和自适应阵列波束形成权值捕获,在码捕获时通过波束形成抑制干扰提高检测性能.对干扰环境下空域最优合并方式的检测性能进行了理论分析,仿真结果与理论预测一致,分析结果表明STC可同时有效的捕获码定时和自适应阵列权值,最优合并方式的虚警概率与干扰和背景噪声功率无关,可实现恒虚警检测.     

衰落信道空间相关对MIMO系统容量的影响

在理想多输入多输出(MIMO)系统容量的基础上,推导了衰落信道空间相关性对MIMO系统容量的影响,并通过MATLAB仿真进行了验证,最后给出了结论。     

An Introduction to Adaptive QAM Modulation Schemes for Known and Predicted Channels

A major disadvantage with fixed modulation (nonadaptive) on channels with varying signal-to-noise ratio (SNR) is that the bit-error-rate (BER) probability performance is changing with the channel quality. Most applications require a certain maximum BER and there is normally no reason for providing a smaller BER than required. An adaptive modulation scheme, on the contrary, can be designed to have a BER which is constant for all channel SNRs. The spectral efficiency of the fixed modulation is constant, while it, in general, will increase with increasing channel SNRs for the adaptive scheme. This in effect means that the average spectral efficiency of the adaptive scheme is improved, while at the same time the BER is better suited to the requirement of the application. Thus, the adaptive link becomes much more efficient for data transmission. The major disadvantage is that the transmitter needs to know the channel SNR such that the best suitable modulation is chosen and the receiver must be informed on the used modulation in order to decode the information. This leads to an increased overhead in the system as compared with a fixed modulation system. In this paper, we introduce adaptive modulation systems by presenting some of the simpler adaptive quadrature amplitude modulation schemes and their performance for both perfectly known and predicted channels.     

非频率选择性衰落MIMO信道上基于序列蒙特卡罗的数字调制识别方法

该文针对非频率选择性衰落多输入多输出(MIMO)信道提出了一种基于序列蒙特卡罗(SMC)方法的幅度-相位调制方式识别方法。首先将MIMO系统等效为一个动态状态空间模型,然后利用序列重要性采样和模式转移步骤估计每根发送天线采用的各种可能调制方式的概率,最后利用各个信道上发送符号的不相关性在长为N的观测信道上进行噪声平均。该方法能够在识别数字调制方式的同时估计发送数据符号。其复杂度是信道观测长度、发送天线数、采样大小、调制星座大小的线性函数。仿真结果表明提出的数字调制识别方法在各种调制星座上具有良好的性能。     

Performance Analysis for LDPC-Coded Modulation in MIMO Multiple-Access Systems

We consider a low-density parity-check (LDPC)-coded modulation scheme in multi-input multi-output (MIMO) multiple-access systems. The receiver can be regarded as a serially concatenated iterative detection and decoding scheme, where the LDPC decoders perform the role of outer decoder and the multiuser demapper does that of the inner decoder. In this paper, we investigate the performance of the scheme with simulation results and bounds. Union upper bounds are derived, which can be used as additional means to evaluate the performance of the MIMO multiple-access system.