Symbol Error Rate Performance Analysis of Non-Orthogonal Multiple Access for Visible Light Communications

Non-orthogonal multiple access(NOMA) is considered as one of promising radio access techniques for visible light communications(VLC) in next-generation wireless communications systems.In order to provide theoretical support for designing VLC-NOMA,we derive its analytic expressions for the symbol error rate(SER).Specifically,NOMA is first incorporated with appropriate VLC to establish a VLC-NOMA framework.Afterwards,mathematical expressions of the SER for the VLC-NOMA are developed.Moreover,numerical results are provided carefully to demonstrate that the proposed VLC-NOMA scheme outperforms than state-of-the-art orthogonal frequency division multiple access(OFDMA) one in terms of SER performance.Finally,relationships between the SER performance and the number of users,power allocation coefficient and semi-angle are well investigated,which can give us a scientific guide to devise the VLC-NOMA system for achieving better SER performance.

Adaptive Linear Filtering Design with Minimum Symbol Error Probability Criterion

Adaptive digital filtering has traditionally been developed based on the minimum mean square error （MMSE） criterion and has found ever-increasing applications in communications. This paper presents an alternative adaptive filtering design based on the minimum symbol error rate （MSER） criterion for communication applications. It is shown that the MSER filtering is smarter, as it exploits the non-Gaussian distribution of filter output effectively. Consequently, it provides significant performance gain in terms of smaller symbol error over the MMSE approach. Adopting Parzen window or kernel density estimation for a probability density function, a block-data gradient adaptive MSER algorithm is derived. A stochastic gradient adaptive MSER algorithm, referred to as the least symbol error rate, is further developed for sample-by-sample adaptive implementation of the MSER filtering. Two applications, involving single-user channel equalization and beamforming assisted receiver, are included to demonstrate the effectiveness and generality of the proposed adaptive MSER filtering approach.

Performance Analysis of Outage Probability and Error Rate of Square M-QAM in Mobile Wireless Communication Systems over Generalized α-μ Fading Channels with Non-Gaussian Noise

This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-Gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results.

基于CP重构的高时间传输效率CP-UFMC接收方法

针对循环前缀(cyclic prefix,CP)不足的情况对循环前缀通用滤波多载波(cyclic prefix-universal filtered multi-carrier,CP-UFMC)系统的影响进行了数学推导,提出了一种基于CP重构的高时间传输效率CP-UFMC接收方法来改善系统性能,并进一步研究了选择性重构方法的性能。之后仿真研究了不同CP长度,不同载波频率偏移和不同正交振幅调制阶数时的系统误符号率(symbol error rate,SER)表现。仿真结果表明,基于CP重构的CP-UFMC接收方法可以改善CP不足导致的系统SER恶化问题,使其接近CP充足时的SER,并优于对比的其他通用滤波多载波系统接收方法。

基于定向天线的DF协作通信系统SER性能分析

针对使用定向天线的协作通信系统,对固定译码转发协议(decode-and-forward protocol,DF)的误符号率(symbol error rate,SER)性能进行探索性研究。首先建立了基于定向天线的DF协作通信系统模型,从理论上推导出该模型下的SER闭式表达式,确定SER上界,并以SER为优化目标分析最优功率分配问题,最后结合具体的数值仿真对所建立模型的SER性能进行详细分析比较。结果表明,在使用定向天线的条件下,DF协作通信系统的SER更小,系统性能优劣与各节点定向增益、信道质量和功率分配方式密切相关,最优功率分配比平均功率分配性能更优。

FinFET器件单粒子翻转物理机制研究评述

鳍式场效应晶体管(FinFET)器件由于其较高的集成度以及运算密度,已成为未来航天应用领域的重要选择。FinFET器件的辐射敏感性与其制作工艺和工作条件息息相关。为了解FinFET器件的单粒子翻转(SEU)敏感机制,文章结合国内外开展的相关研究,从SEU机理出发,分析了器件特征尺寸、电源电压和入射粒子的线性能量传输(LET)值等不同条件对器件SEU敏感性的影响,最后结合实际对FinFET器件SEU的研究发展方向进行展望。

不同功率分配与中继位置下协同通信SER性能分析

在中继端运动与静止两种情况下分析了一个两用户放大转发协同通信系统的误码率(symbol-error-rate,SER)性能。首先得到M-PSK调制下的SER封闭表达式与相应上界,以此提出一个最优功率分配方案(optimum power allocation,OPA),目的是使得SER最小,然后讨论了在最优与等功率分配(equal power allocation,EPA)两种方案下中继按照椭圆拓扑运动时对SER的影响。EPA方案下,精确最优中继位置恰在源端与目的端的中点处,但是在OPA方案下最优位置却离目的端更近,并且,无论中继端运动还是静止,OPA方案都能得到比EPA更好的SER性能。

移动物联网通信中的UFMC调制波形优化设计

移动物联网(Internet of Things, IoT)通信是6G的关键技术之一,面对多变的地面基站环境,无人机(Unmanned Aerial Vehicle, UAV)辅助通信被认为是物联网通信的重要组成部分,已受到广泛关注。通用滤波器多载波(Universal Filtered Multi-carrier, UFMC)作为一种新型非正交多载波调制技术,继承了正交频分复用(Orthogonal Frequency Division Multiplexing, OFDM)的优势,主要应用在短数据包突发通信场景中,被认为适用于下一代无线物联网通信。但是,在无人机的高速移动环境下,通信信号会遭受显著的多普勒频移影响,产生严重的载波间干扰(Inter Carrier Interference, ICI),导致UFMC系统性能的显著下降。为了缓解ICI问题,本文首先理论分析、推导了存在多普勒频移时UFMC系统的信干噪比(Signal to Interference plus Noise Ratio, SINR)。根据SINR分析,可见将UFMC波形滤波器通带波动优化调控的足够小以及加快过渡带衰减有利于提升系统抗ICI能力。因此,本文提出了基于波形滤波器优化设计的干扰抑制方法,构建了符合UFMC通信需求的波形滤波器最优化设计数学模型,该模型可以有效地调控波形滤波器的通带波动,通过遍历搜索可求解得到使系统误符号率(Symbol Error Rate, SER)相对最优的波形滤波器。在考虑多普勒频移的系统仿真中,SER对比结果表明:与采用传统波形滤波器的UFMC系统相比,本文根据约束最小最大(Constraint Minimax, CMM)准则遍历搜索设计的波形滤波器可以有效地抑制系统ICI从而改善SER。这为未来移动物联网通信系统的波形设计提供了参考。

相关衰落信道上M进制信号的SER近似计算

研究相关Nakagami-m衰落信道上采用最大比合并分集接收的M进制相移键控,M进制差分相移键控的平均误符号率性能,采用互补误差函数的方法来计算平均误符号率的上下限。数值计算结果表明该平均误符号率性能上限和下限能够较好地表征相关Nakagami-m衰落信道上M进制相移键控和M进制差分相移键控的平均误符号率性能。

瑞利衰落信道上DF协作系统SER性能分析

对平坦瑞利衰落信道上解码转发(DF)中继协作系统的误符号性能进行了分析。利用矩生成函数(MGF)方法 ,推导出了该系统采用相干检测M进制相移键控(MPSK)时的平均误符号率(SER)的闭合表达式。数值计算结果表明了接收端平均信噪比(SNR)越大,DF中继协作系统误码性能越好。仿真结果证实了理论分析结果的正确性。

AWGN信道高阶调制物理层网络编码的SER性能

扩展了最近邻近似方法使之能描述物理层网络编码的误符号率,并用该方法分析了双向中继网络中物理层网络编码在高阶调制下的误符号率.以8PSK为例,推导了高阶调制下PNC在AWGN信道中误符号率的闭式表达.研究发现,固定一个源节点的发射功率时,系统的SER并不会随着另一端源节点功率的提高而单调递减.蒙特卡罗仿真结果表明,所得表达式能正确刻画8PSK调制下物理层网络编码的误符号率.

SER analysis and power allocation for hybrid cooperative transmission system

The symbol-error-rate（SER） and power allocation for hybrid cooperative（HC） transmission system are investigated.Closed-form SER expression is derived by using the moment generating function（MGF）-based approach.However,the resultant SER contains an MGF of the harmonic mean of two independent random variables（RVs）,which is not tractable in SER analysis.We present a simple MGF expression of the harmonic mean of two independent RVs which avoids the hypergeometric functions used commonly in previous studies.Using the simple MGF,closed-form SER for HC system with M-ary phase shift keying（M-PSK） signals is provided.Further,an approximation as well as an upper bound of the SER is presented.It is shown that the SER approximation is asymptotically tight.Based on the tight SER approximation,the power allocation of the HC system is investigated.It is shown that the optimal power allocation does not depend on the fading parameters of the source-destination（SD） channel and it only depends on the source-relay（SR） and relay-destination（RD） channels.Moreover,the performance gain of the power allocation depends on the ratio of the channel quality between RD and SR.With the increase of this ratio,more performance gain can be acquired.

SER-Tvpack:基于软错误率评估的SRAM型FPGA的装箱算法

为了提高基于SRAM的FPGA(SFPGA)上的容软错误能力,提出了一种基于软错误率(soft error rate,SER)评估的装箱算法SER-Tvpack.通过结合软错误率的两个组成部分错误传播率(error propagation probability,EPP)和节点错误率(node error rate,NER),得到软错误评估标准SER的估算值,并将该值作为可靠性因子加入到代价函数中指导装箱过程,以减少装箱后可编程逻辑块(configuration logic block,CLB)之间互连的软错误率,从而提高设计的可靠性.对20个MCNC基准电路(最大基准电路集)进行实验,结果表明,与基准时序装箱算法T-Vpack及已有的容错装箱算法FTvpack相比较,软故障率分别减少了14.5%和4.11%.而且,与F-Tvpack比较,在仅增加0.04%的面积开销下,减少了2.31%的关键路径的时延,提供了较好的时序性能.

CSK调制信号的跟踪方法

CSK调制信号能够满足GNSS厘米级高精度服务的高信息速率播发需求,正受到广泛关注。针对CSK调制信号只能用于播发数据,而不能用于提供测量观测量的问题,对CSK调制信号的跟踪方法进行了研究。通过权衡性能和实现复杂度,提出了两种跟踪方法,方法一跟踪精度高但实现复杂度高,方法二以损失跟踪精度为代价降低了实现复杂度。理论和仿真分析结果表明,所提方法一在CSK调制信号载噪比高于40 dB-Hz时,可提供与BPSK信号相当的跟踪性能。方法二相比方法一所需相关器资源降低一半,性能损失约4 dB。论文的研究成果可为CSK调制信号在GNSS高精度信号体制中的应用提供支持。

OPTIMAL POWER ALLOCATION WITH AF AND SDF STRATEGIES IN DUAL-HOP COOPERATIVE MIMO NETWORKS

Dual-hop cooperative Multiple-Input Multiple-Output (MIMO) network with multi-relay cooperative communication is introduced. Power allocation problem with Amplify-and-Forward (AF) and Selective Decode-and-Forward (SDF) strategies in multi-node scenario are formulated and solved respectively. Optimal power allocation schemes that maximize system capacity with AF strategy are presented. In addition, optimal power allocation methods that minimize asymptotic Symbol Error Rate (SER) with SDF cooperative protocol in multi-node scenario are also proposed. Furthermore, performance comparisons are provided in terms of system capacity and approximate SER. Numerical and simulation results confirm our theoretical analysis. It is revealed that, maximum system capacity could be obtained when powers are allocated optimally with AF protocol, while minimization of system's SER could also be achieved with optimum power allocation in SDF strategy. In multi-node scenario, those optimal power allocation algorithms are superior to conventional equal power allocation schemes.

Analysis of asymptotically tight approximation SER for cooperative NOMA systems

The closed-form formula derivation of the power domain cooperative non-orthogonal multiple access(NOMA)system is of great significance for further improving the performance of the system.However,the system performance formulas of the channel capacity and the paired bit error rate pairwise error probability(PEP)are too complicated,which have increased the difficulty in system performance optimization.Therefore,based on the amplify forward(AF)relay cooperative NOMA model,the signal interference noise ratio(SINR)formulas of the two user nodes are constructed.Through the assumption of that,the symbol error rate(SER)of each user is fair,the simplification condition of moment generating function(MGF)with the harmonic mean form is satisfied.Combined with the SER calculation formula of MGF,the system SER asymptotically tight approximation formula with simple structure is derived at high signal-to-noise ratio(SNR).The Monte Carlo simulation results show that,the formula can accurately describe the SER performance of the power domain cooperative NOMA system with the non-ideal successive interference cancellation(SIC)system when SNR is high.Under the condition of certain total power,the optimal power allocation factor is solved in order to minimize the total system SER.

Modified Cooperative Subchannel Allocation Algorithms and PSO Based Power Allocation for an Alamouti Decode and Forward Relaying Protocol in Multiuser OFDMA Systems

The present work is a discussion on the performance analysis of Modified Cooperative Subchannel Allocation (CSA) Algorithms which is used in Alamouti Decoded and Forward (Alamouti DF) Relaying Protocol for wireless multi-user Orthogonal Frequency Division Multiplexing Access (OFDMA) systems. In addition, the performance of approximate Symbol Error Rate (SER) for the Alamouti DF Relaying Protocol with the Cooperative Maximum Ratio Combining Technique (C-MRC) is analyzed and compared with SER upper bound. The approximate SER is asymptotically tight bound at higher Signal-to-Noise Ratio (SNR). From the asymptotic tight bound approximate SER, Particle Swarm Optimization (PSO) based Power Allocation (PA) is determined for the Alamouti DF Relaying Protocol. The simulation results suggested that the Modified Throughput based Subchannel Allocation Algorithm achieved an improved throughput of 6% to 33% compared to that of existing cooperative diversity protocol. Further, the Modified Fairness based Subchannel Allocation Algorithm rendered fairness of 7.2% to 17% among the multiuser against the existing cooperative diversity protocol.

一种具有多普勒容忍性的通感一体化波形设计

针对现有联合设计的通感一体化波形对运动目标探测性能不足的问题,该文提出了一种具有多普勒容忍性的通感一体化波形联合设计方案。首先,基于脉冲串模糊函数,推导了构造多普勒容忍波形等价于波形在相关区内具有极低的积分旁瓣电平。基于此,构建了以最小化一体化波形的加权积分旁瓣电平为优化准则,以发射波形的能量、峰均功率比以及与通信波形之间的相位差为约束条件的优化问题,从而实现具有多普勒容忍性的通感一体化波形的构造。由于该优化问题的非凸性,该文提出一种基于优化最小化的迭代优化算法对其进行求解。数值仿真实验表明,相比传统一体化波形,该文提出的一体化波形具有更高的多普勒容忍性和更低的误符号率,在保证通信质量的前提下显著提升了通感一体化系统对运动目标的探测性能。

临频差分调制技术研究

调制技术是通信的基础。文章讨论一种在频率域进行差分处理,以提高抗干扰性能的频域差分调制技术。它采用多个频率传输一个码元,形成一个合成信号在同一个信道中传输,噪声对该信号干扰时会对多个频点作用,由于多频点信道完全相同,因此其干扰也相似,解调时可利用差分技术降低干扰影响。文章研究了2个频率相近载波的临频差分调制(Non-orthogonal Frequency Division Multiplexing,NFDM),当输入信噪比为-6 DB时,误码率约为10^(-4),与信噪比+8 DB时OFDM的误码率相似,说明NFDM有很好的抗干扰能力。