BER Performance Analysis of Asynchronous NOMA with Arbitrary Phase Offset

An asynchronous transmission scenario for non-orthogonal multiple access(NOMA)user signals with arbitrary phase offset is investigated in this paper.To improve the system performance in the user power-balanced conditions,we adopt a synthetic detection method at the receiver,i.e.,the jointly optimal maximal likelihood detection aided triangular successive interference cancellation(JO ML-TSIC)method.Analytical bit error rate(BER)solutions are obtained for a two-user case with the optimal,intentional onehalf symbol period time delay implemented between the user signals.Furthermore,closed-form BER solutions for the case using the triangular successive interference cancellation(TSIC)detection method are also derived for comparisons.Numerical results show that the JO ML-TSIC receiver for the asynchronous system outperforms the TSIC receiver as well as the synchronous successive interference cancellation(SIC)receiver in all the conditions concerned.The results also show that the superiority of the JO ML-TSIC receiver is strengthened when the signals experience flat Rayleigh fading channels compared to the TSIC and the synchronous SIC receivers.

32×10Gbit密集波分复用系统仿真

分析了DWDM技术及系统的设计原理,在此基础上,给出了基于Optisystem的DWDM光传输链路仿真模型的搭建,对复用及解复用后的光信号进行仿真得出光谱图,对链路传输性能及Q因子、误码率、眼图的等参数进行分析,并验证了波分复用系统的正确性和设计方案的可行性,近而得出相关结论。

软判决维特比译码算法的Simulink仿真实现(英文)

通过研究软判决维特比译码算法的基本原理,提出了一种基于Simulink的软判决维特比译码算法建模仿真方法。为了验证该算法模型的正确性。建立了基于Simulink的具有卷积编码、软判决维特比译码完整的通信系统仿真模型,通过仿真所得到的误码率与软判决理论误码率的对比证明了所建立的仿真系统的正确性。最后,为了比较硬判决译码算法与软判决译码算法的性能,建立了硬判决维特比译码算法的仿真模型,并与软判决维特比译码性能进行了对比分析,仿真结果表明:在相同误码性能条件下,软判决译码算法的信噪比要比硬判决译码算法提升2 dB。

一种基于RS码序列的软扩频系统及其Simulink仿真

介绍软扩频系统和里德-索罗门编码的基本原理,提出一种基于里德-索罗门码序列的软扩频系统,并且用Simulink仿真工具对该系统进行了建模。为了验证系统的抗干扰性能,对其进行了仿真分析,给出了这种软扩频系统和一般直扩频系统在单频干扰和宽带干扰下的误码率,仿真结果表明:这种基于里德-索罗门码序列的软扩频系统对单频信号干扰和宽带干扰有很好的抑制效果。

OFDM系统研究及其Simulink仿真

正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)是一种高效的多载波宽带数字调制技术,在无线通信系统中有较广泛的应用。通过对OFDM系统的基本原理以及该系统中各个模块的特点进行研究,用Simulink构建数字电视地面广播(Digital Television Terrestrial Broadcasting,DTTB)中的TDS-OFDM系统仿真模型。仿真结果表明,TDS-OFDM系统的误码率较低,具有较强的抗多径衰落和频率选择性衰落能力。

基于Simulink的Turbo码系统仿真

在Turbo码编码、译码基本理论和结构的基础上,提出了一种用Simulink构建的Turbo码编、译码可控仿真模型,并在BPSK(binary phase-shift keying)调制的高斯白噪声信道(AWGN)中进行了系统建模和仿真实验.通过研究Turbo编码、卷积编码和无信道编码方案仿真系统的BER(bit error rate)性能,结果表明,所提出的Turbo编码的误码率优于其他2种方案1个数量级以上,尤低信噪比时更具优势.

非对称调制的双向全双工车载通信BER性能分析

在车载通信系统中,全双工中继技术可满足车联网的低时延需求以及缓解频谱资源短缺问题。然而,实际车载通信应用中不同信源车辆发送的信息相互独立,节点调制方式往往不对称。这种非对称传输会加剧全双工模式残余自干扰造成的译码错误。针对这一问题,提出一种非对称调制的全双工通信方法,该方法引入网络编码联合调制的解码转发方式解决了非对称调制带来的误码率增大的问题。此外,分析了全双工残余自干扰随功率动态变化情况下的优化约束条件,得到最优功率分配区间。数值分析结果证明:在不同功率区间内,所提方法都可找到最优功率比例,使得系统端到端误比特性能最优。

提高MIMO信道BER性能的干扰对齐方案

为提高多输入多输出(MIMO)X信道的比特误码率(BER)性能,提出一种干扰对齐方案。在发送端将数据按照Alamouti编码方案重复发送,在接收端通过重新配置天线工作模式改变信道系数,构成具有正交结构的等效信道矩阵,通过矩阵运算消除干扰,并采用低复杂度的PIC群译码算法进行译码。仿真结果验证了该方案的有效性。

Performance analysis and design of MIMO-OFDM system using concatenated forward error correction codes

This work investigates the performance of various forward error correction codes, by which the MIMO-OFDM system is deployed. To ensure fair investigation, the performance of four modulations, namely, binary phase shift keying(BPSK), quadrature phase shift keying(QPSK), quadrature amplitude modulation(QAM)-16 and QAM-64 with four error correction codes(convolutional code(CC), Reed-Solomon code(RSC)+CC, low density parity check(LDPC)+CC, Turbo+CC) is studied under three channel models(additive white Guassian noise(AWGN), Rayleigh, Rician) and three different antenna configurations(2×2, 2×4, 4×4). The bit error rate(BER) and the peak signal to noise ratio(PSNR) are taken as the measures of performance. The binary data and the color image data are transmitted and the graphs are plotted for various modulations with different channels and error correction codes. Analysis on the performance measures confirm that the Turbo + CC code in 4×4 configurations exhibits better performance.

Multi-Bit Sliding Stack Decoding Algorithm for OVXDM

Overlapped x domain multiplexing(OVXDM) is a promising encoding technique to obtain high spectral efficiency by utilizing inter-symbol interference(ISI) intelligently. However, the computational complexity of maximum likelihood sequence detection(MLSD) increases exponentially with the growth of spectral efficiency in OVXDM, which is unbearable for practical implementations. In this paper, based on a novel path metric associating adjacent symbols, we propose a multi-bit sliding stack decoding(Multi-Bit SSD) algorithm to achieve multiple-bit decoding simultaneously in OVXDM. Theoretical analysis is provided for the algorithm, which indicates the relationship between the performance and parameters including multiplexing waveform, overlapping fold and sliding window size. Simulation results show that the proposed algorithm can achieve better decoding performance and higher spectral efficiency than conventional fast decoding algorithms.

Improving the BER performance of turbo codes with short frame size based on union bound

timizing the formula, the energy for every bit of the codeword is optimized to achieve the minimum BER at high SNR region. At last, an adjustable parameter is employed to compensate the degrada- tions of BER at low and moderate SNR regions. Case studies indicate that the improvements of BER for turbo codes with short frame size are significant at a wide range of SNR

BER ANALYSIS OF A GMSK SYSTEM USING DECISION FEEDBACK

There are considerable literatures on the Bit Error Rate(BER)evaluation of DifferentialDetection of Gaussian Minimum Shift Keying(DDGMSK)system using Decision Feedback(DF),butmost of them give the performance based on the Monte Carlo Error Counting(MCEC)technique.Fromthe probability distribution of the phase angle between two vectors perturbed by Gaussian noises,theformulae of BER are derived for the performance analysis of DDGMSK system with DF in this letter.Considering the m-bit dock-tailed sequence,the new formulae of Gaussian Minimum Shift Keying(GMSK)modulated phase and the Time-Varying Signal to Noise Ratio(TVSNR)of the demodulatedsignal are presented,and it is proved that the relationship between the TVSNR of the demodulatedsignal and the size of eye opening is not inevitable.Simulation results show that the theoretical in-vestigation gives analogous results with the MCEC technique.The formulae presented are useful for theperformance analysis of systems using GMSK as modulating and demodulating method,for instance,the analysis of synchronous performance of frequency-hopping communication system.

基于Simulink的高速跳频通信系统仿真

跳频技术具有较强的抗干扰、抗噪声,抗频率选择性衰减的能力和较低的误码率。在阐述跳频通信基本原理和实现方法的基础上,利用Matlab提供的可视化工具Simulink建立了跳频通信系统仿真模型,详细阐述了各模块设计。仿真平台可以通过提供的可视化界面设置参数,同时可以直观地显示收发双发频率的跳变、误码率等重要指标。仿真结果表明,该跳频通信系统工作正常,达到了预期效果。

BER Performance of Finite in Time Optimal FTN Signals for the Viterbi Algorithm

In this article, we consider the faster than Nyquist(FTN) technology in aspects of the application of the Viterbi algorithm(VA). Finite in time optimal FTN signals are used to provide a symbol rate higher than the "Nyquist barrier" without any encoding. These signals are obtained as the solutions of the corresponding optimization problem. Optimal signals are characterized by intersymbol interference(ISI). This fact leads to significant bit error rate(BER) performance degradation for "classical" forms of signals. However, ISI can be controlled by the restriction of the optimization problem. So we can use optimal signals in conditions of increased duration and an increased symbol rate without significant energy losses. The additional symbol rate increase leads to the increase of the reception algorithm complexity. We consider the application of VA for optimal FTN signals reception. The application of VA for receiving optimal FTN signals with increased duration provides close to the potential performance of BER,while the symbol rate is twice above the Nyquist limit.

BER Performance of Space-Time Coded MMSE DFE for Wideband Code Division Multiple Access (WCDMA)

In recent times, there has been growing interests in integration of voice, data and video traffic in wireless communication networks. With these growing interests, WCDMA has immerged as an attractive access technique. The performance of WCDMA system is deteriorated in presence of multipath fading environment. The paper presents space-time coded minimum mean square error (MMSE) Decision Feedback Equalizer (DFE) for wideband code division multiple access (WCDMA) in a frequency selective channel. The filter coefficients in MMSE DFE are optimized to suppress noise, intersymbol interference (ISI), and multiple access interference (MAI) with reasonable system complexity. For the above structure, we have presented the estimation of BER for a MMSE DFE using computer simulation experiments. The simulation includes the effects of additive white Gaussian noise, multipath fading and multiple access interference (MAI). Furthermore, the performance is compared with standard linear equalizer (LE) and RAKE receiver. Numerical and simulation results show that the MMSE DFE exhibits significant performance improvement over the standard linear equalizer (LE) and RAKE receiver.

基于OFDM系统的Simulink仿真过程研究

本文主要介绍了正交频分复用系统(Orthogonal Frequency Division Multiplexing,OFDM)的基本原理,给出了基于IFFT/FFT实现了OFDM系统仿真模型,基于Simulink完成了对OFDM的仿真,研究了在高斯信道和不同条件的瑞利信道下的OFDM系统性能。对系统误码率进行分析,得出了很多较理想结论。

THE THEORETICAL BER PERFORMANCE ANALYSIS OF A COOPERATIVE DIVERSITY SCHEME IN FREQUENCY SELECTIVE FADING CHANNEL

A novel cooperative diversity scheme based on Distributed Space-Time Block Coding and Multi-Carrier Code Division Multiple Access (DSTBC-MC-CDMA) is proposed which works well in frequency selective fading channels with multiple single-antenna users. And an analytical error model is established to describe the symbol decoding errors between interusers, based on which a close form expression for theoretical Bit Error Rate (BER) performance of the scheme is derived to analyze the influence of the interuser decoding errors on the BER performance of the scheme. Then simulation is complimented to verify the analytic result above, which also shows that the BER performance of DSTBC-MC-CDMA outgoes that of non-cooperative MC-CDMA with considerable gains. Further- more, the simulations coincide with the theoretical results well.

基于Simulink的OFDM系统仿真研究

本文主要介绍了正交频分复用系统(Orthogonal Frequency Division Multiplexing,OFDM)的基本原理,给出了基于IFFT/FFT实现了OFDM系统仿真模型,基于Simulink完成了对OFDM的仿真,研究了在高斯信道和不同条件的瑞利信道下的OFDM系统性能。对系统误码率进行分析,得出了很多较理想结论。

不同调制方式OFDM系统的Simulink仿真

OFDM(Orthogonal Frequency Division Multiplexing)因其独特优势成为目前无线移动通信的主要技术。针对不同调制方式的OFDM系统,论文首先阐述了OFDM技术基本原理,进而基于MATLAB的Simulink平台,构建了不同调制方式OFDM系统仿真模型,详细叙述系统仿真实现的方法步骤,并仿真分析了OFDM信号的频谱和时域波形。最后,对比分析了不同信噪比下三种调制方式对应OFDM系统的误码率性能,并分析了其内在机理。