SDH光缆数字线路系统误码性能指标及测试

介绍了SDH光缆数字线路系统的基本概念,讨论了系统误码性能的度量、误码指标的计算及测试,并介绍了误码性能测试的方法。     

自由空间光通信中误码测试系统的开发

提出了一种基于FPGA的误码测试系统的设计方案,对其中的关键技术进行了论述.该测试系统已成功应用于自由空间光通信系统中,经过仿真和实际应用验证,该方案是行之有效的.     

SDH系统误码性能在线测试方法的准确性分析

对于大容量、高速率的SDH传输系统,在线测试是很经济、有效的测试手段,ITU-T规范了SDH系统误码性能的在线测试方法为BIP码校验。然而,有些在线测试方法自身决定了检测的不完全性。SDH的BIP码校验也不例外,用于SDH在线测试时,由于对基本检测事件——差错块检测的不完全,将最终导致评估G.826误码性能参数的不准确。本文定量分析了SDH系统误码性能在线测试方法的准确度,其结果可用于SDH仪表和SDH设备监测装置中与误码性能评估有关的设计。     

FSO通信误码测试仪硬件设计

介绍了一种基于AT89S52单片机和EP1K30 FPGA的FSO通信误码测试系统的设计与实现方案.系统以FPGA为处理核心,实现高速误码检测;单片机完成控制逻辑.详细讨论了伪随机码发生模块、同步模块、误码检测模块及单片机与FPGA接口的软硬件设计.并利用设计的样机进行了本地光纤环回和实验室内近距离无线激光通信的误码测试实验,实验结果表明此设计工作稳定可靠,可以实现对FSO通信质量进行检测的设计要求.     

数字卫星通信系统的误码性能指标和测试

数字卫星通信系统的误码性能指标和测试陈肇基误码是数字卫星通信系统最重要的质量指标。为了了解数字卫星通信系统的运行质量，必须对全系统的误码性能进行测量。数字卫星通信系统误码性能的测量分中断业务测量和在线监测两种。中断业务测量用于数字卫星通信系统竣工验收...     

基于OFDM的LDPC误码测试系统设计

通过比较国内外几种LDPC误码平台测试系统,设计了一种基于OFDM的用于测试LDPC解码误码性能的窄带系统,采用了时域同步正交频分复用调制方式,具有抵抗多径干扰和多普勒频移的能力.该系统用FPGA予以实现,不仅可用于实验室测试,也可用于测试真实多径环境下的误码性能,还能作为通用系统用于其他信道纠错码的解码误码测试.     

SDH系统误码性能的在线测试

对于大容量，高速率的ＳＤＨ传输系统，主要承担信息的传输任务，其传输性能的优劣影响极大，而误码又是主要的传输损伤之一。所以，误码性能的在线测试是十分必要的测试手段。本文以ＩＴＵ－Ｔ建议Ｇ．８２６为基础，介绍了ＳＤＨ系统误码性能在线测试的特点、方法，原理以及准确性。     

FPGA在误码测试仪中的应用

误码测试是数字通信系统最基本的测量方法之一。使用FPGA实现误码测试功能．不仅可提高系统集成度,而且能适合不同类型的测试要求。本文给出了FPGA在误码测试仪中的应用方法。     

误码测试IP核的设计

提出了一种误码测试IP核的设计方案,可嵌入通信系统,作为系统自检单元的一部分完成系统的误码测试。通过IP核内置的异步串行接口,计算机可以对IP核进行参数配置,并读取误码数据进行性能分析。文中介绍了误码测试IP核结构和关键技术的实现,最后给出了计算机上测试软件的开发方法。     

SDH光缆数字线路系统误码性能指标及测试

介绍了SDH光缆数字线路系统的基本概念，讨论了系统误码性能的度量、误码指标的计算及测试，并介绍了误码性能测试的方法。     

频率选择性衰落信道GMSK误码性能分析

通过对数字移动信道脉冲响应时延展宽包络 ( PDSP)波形的研究 ,分析了GMSK调制下的脉冲时延展宽包络与误码率之间的变化关系 ,建立了两者之间关系的理论模型和计算机仿真模型 ,同时给出了在四种较为典型的 PDSP作用下 ,GMSK误码率特性的计算机仿真结果。     

磁光存储系统数据信道误码特性分析

本文分析了磁光存储系统产生误码的原因，针对系统在读取数据“１”和“０”时信道噪声强度不同这一特殊性，导出了描述信道误码特性的数学模型，并在此基础上研究了磁光信号检偏方式与信道误码特性的关系。分析结果表明：平衡差分信道的容功错能力略高于非平衡差分信息道。     

Reducing Host Interference from Spread Spectrum Watermarking

Spread spectrum watermarking (SSW) is one of the most promising watermarking techniques. While SSW is very robust against additive noise, it suffers from an inherent noise. The noise results from host interference on detection of the embedded hidden information. The host interference is one of the main reasons for the relatively low embedding rate in SSW and its reduction is important. In this paper, a new method for use in an SSW detector is proposed to reduce the host interference. The proposed method is based on the law of large numbers and symbol detection of embedded information, instead of bit detection. Since the method is based on the detection of symbols longer than one bit, the detector can employ PN sequences with a larger length, resulting in decrease of the interference. The symbol error rate using this algorithm is calculated employing the maximum a posteriori criterion. Comparison of bit error rates between the modified SSW algorithm and conventional bit detection shows that the modified algorithm is much more robust against the host interference.     

Joint Hadamard transform and Alamouti scheme for wireless communication system

In this letter, the joint of Hadamard transform and Alamouti scheme is proposed. By applying Hadamard transform in the Alamouti scheme, two points of constellation can be merged into one symbol. This symbol is used for input of Alamouti scheme without changing the behavior of Alamouti scheme. System model for joint Hadamard transform and Alamouti scheme is also suggested and formulated. Simulation results show that the bit error rate (BER) performance of the proposed scheme outperforms the original Alamouti scheme.     

Clustering source output bits and equalizing bit error sensitivity to improve the quality and robustness of transmitted images over wireless channels

A joint design of source coding and channel coding is proposed to transmit images over error-prone wireless channels. First, the importance of each source output bit is quantified in bit error sensitivity (BES). Next, clustered set partitioning in hierarchical trees (C-SPIHT) is adopted to cluster SPIHT output bits so that the resultant bit-clusters have distinct BES. Then, we prove that equalizing the mean BES of bit-clusters provides the optimal assignment of channel coding rates for the unequal error protection. Besides, to achieve the best PSNR performance under a transmission rate, we use a heuristic method to allocate the source coding rate and channel coding rate. Simulation results show that, under different channel bit error rates, our design not only improves the mean PSNR performance, but also reduces the variations of PSNR performance, i.e. the robustness of PSNR to the channel noise interference is improved.     

基于DS2172的误码测试仪的设计

在数字通信工程中,误码率是检验数据传输设备及其信道工作质量的一个主要指标,给出了采用AT89C51单片机结合误码测试器DS2172实现简单误码测试仪的设计.     

Comments on “A new and exact analysis of DS-CDMA cellular radio system based on the physical interpretation of Nakagami wideband channel”

Explicit expressions are derived for the probabilities of the bit error of the DS-CDMA cellular system considered by Abdel-Hafez and Alagoz [A new and exact analysis of DS-CDMA cellular radio system based on the physical interpretation of Nakagami wideband channel. AEU - Int J Electron Commun 2004;58:330–8].     

Throughput Optimization for Wireless LANs in the Presence of Packet Error Rate Constraints

In [1], we optimized single-user throughput by selecting the transmitted bit rate and payload size as a function of channel conditions. However, the approach did not consider a packet error rate (PER) constraint, and the payload size obtained could yield excessively high packet error rates. We propose and solve the optimization problem of maximizing throughput by varying the PHY layer data rate and the payload size subject to a packet error rate constraint. The resulting SNR thresholds for adapting the PHY data rate and the corresponding payload sizes are drastically different than those obtained without the PER constraint.     

QAM调制分析与其SystemView仿真实现

正交振幅调制OAM(Ouadrature Amplitude Modulation)是一种频谱利用率很高的调制方式.文章在介绍OAM调制、解调原理的基础上,深入探讨了OAM的频谱利用率和误码率性能.并在SystemView下对该系统进行了完整仿真.通过仿真观察到调制与解调信号的波形,星座图以及OAM信号功率谱密度曲线,并对仿真结果进行了分析.由分析结果可知,OAM调制系统具有很高的频谱利用率以及较好的误码率性能,因此可增大系统容量,同时也保证了系统的可靠性.