New approach for improving throughput in multi-channel packet radio systems

A new approach for improving the throughputs of multi- channel packet radio systems is proposed. Based on the charac- teristics of multi-code CDMA technology, the scheme factitiously improves the transmission bit rate of a terminal by compressing the packet transmission time and thereby increases the number of the orthogonal spreading codes used by the terminal. By this means, the average interference level of the system is reduced and the system capacity is improved. Simulation results show that the proposed scheme exhibits larger throughput compared with the traditional multi-code CDMA slotted Aloha systems.

PERFORMANCE ANALYSIS OF FREQUENCY HOPPING PACKET RADIO NETWORK WITH ACKNOLEDGEMENT TRAFFIC

Performance analysis of an asynchronous frequency hopping packet radio network and numerical results are given. The network has mixed traffic, one type of packet needs an Acknowledgement(Ack), the other type does not need, the background of such a network is tactical missile systems. A reasonable network model is given, based on which the effect of various parameters under multiaccess interference is investigated. The performance curves of throughput and average packet delay is given in this paper.

A New Fairness-Oriented Packet Scheduling Scheme with Reduced Channel Feedback for OFDMA Packet Radio Systems

In this paper, we propose a flexible and fairness-oriented packet scheduling approach for 3GPP UTRAN long term evolution (LTE) type packet radio systems, building on the ordinary proportional fair (PF) scheduling principle and channel quality indicator (CQI) feedback. Special emphasis is also put on practical feedback reporting mechanisms, including the effects of mobile measurement and estimation errors, reporting delays, and CQI quantization and compression. The performance of the overall scheduling and feedback re-porting process is investigated in details, in terms of cell throughput, coverage and resource allocation fairness, by using extensive quasistatic cellular system simulations in practical OFDMA system environment with frequency reuse of 1. The performance simulations show that by using the proposed modified PF ap-proach, significant coverage improvements in the order of 50% can be obtained at the expense of only 10-15% throughput loss, for all reduced feedback reporting schemes. This reflects highly improved fairness in the radio resource management (RRM) compared to other existing schedulers, without essentially com-promising the cell capacity. Furthermore, we demonstrate the improved functionality increase in radio re-source management for UE’s utilizing multi-antenna diversity receivers.

Performance Prediction of Packet Mobile Communication through Wireless Multipath Fading Channel Modeling

This paper presents a software simulator applicable to multipath fading channels in urban environments of mobile communication networks. The simulator is constructed by a two-state Markov model and several statistical models for simulating the characterizations of different environments. A core idea of the simulator is to construct a Rice distribution-based multipath fading module produced by a modified Gans Doppler power spectrum, and in combination with a Markov model to predict the time-dependent characteristics of packet in different radio circumstances. It can simply predict the packet performance of the future channel and evaluate the relations between the radio channel and the modulation schemes, error control protocols and channel coding. Simulation results demonstrate that it is a reliable and efficient method.

A Novel Transceiver Architecture Based on Wavelet Packet Modulation for UWB-IR WSN Applications

In last few years, several recent developments concern a new proposed techniques of communication for WSN (Wireless Sensors Network) using a complex methods and technics. This network is considered a future platform for many applications like: medical, agriculture, industrial, monitoring and others. The challenge of this work consists in proposing a new design of transceiver for WSN based on IDWPT (Inverse Discrete Wavelet Packet Transform) in emitter and DWPT (Discrete Wavelet Packet Transform) in receiver for mono and multi users using AWGN Channel. We will propose in this paper, a new concept of impulse radio communication for multiband orthogonal communication for UWB (Ultra-wideband) applications. The main objective of this work is to present a new form of pulse communication adapted to low through-put short-range applications and is scalable according to the type of use but also the number of sensors.

Joint Optimization Strategy for Video Transmission over Distributed Cognitive Radio Networks

A novel joint optimization strategy for the secondary user( SU) was proposed to consider the short-term and long-term video transmissions over distributed cognitive radio networks( DCRNs).Since the long-term video transmission consisted of a series of shortterm transmissions, the optimization problem in the video transmission was a composite optimization process. Firstly,considering some factors like primary user's( PU's) collision limitations,non-synchronization between SU and PU,and SU's limited buffer size, the short-term optimization problem was formulated as a mixed integer non-linear program( MINLP) to minimize the block probability of video packets. Secondly,combining the minimum packet block probability obtained in shortterm optimization and SU's constraint on hardware complexity,the partially observable Markov decision process( POMDP) framework was proposed to learn PU's statistic information over DCRNs.Moreover,based on the proposed framework,joint optimization strategy was designed to obtain the minimum packet loss rate in long-term video transmission. Numerical simulation results were provided to demonstrate validity of our strategies.

联合小波-频域变换的自适应能量检测

针对传统能量检测方法在频谱感知领域中极易受低信噪比环境干扰,忽视可用频谱的定位亦会影响频谱状态的判别结果,提出了一种联合小波-频域变换的自适应能量检测方法,旨在提高能量检测的噪声灵敏度和判别精确度。通过离散小波包变换对信号进行分解并计算子带能量;结合能量范数降低自适应阈值的计算复杂度,以便与子带能量比较;采用快速傅里叶变换定位可用频谱范围。对该方法进行模拟仿真,探究自适应阈值与不同性能参数之间的变化关系。仿真结果表明,该方法具有良好的环境适配性与系统稳定性,且在不同信噪比环境下的检测误差更小。此外,对子带信号进行频域分析以实现归一化频率范围的重新排序,进一步提高了频谱感知的准确度。

基于单片机的家居环境监测器设计研究

该文提出一套基于单片机的家居环境监测器的设计方案。以STC89C516单片机作为主控模块,使用霍尔传感器、盖革计数管和甲醛传感器作为数据采集模块,实时获取室内电磁辐射强度、电离辐射剂量率和甲醛浓度的监测数据,并通过GPRS通信模块,将3项监测数据以短信方式向房主手机定时发送。初步测试中,在系统程序指定手机上成功接收到3项监测数据,均值分别为4.61 mT、1.0372 mSv/y和0.0499 mg/m^(3)。测试结果表明,系统总体设计合理、各功能模块运行稳定,实现多参数实时监测的预期目标,可应用于家居环境的监测。

基于GPRS技术的输电线路状态数据通信系统设计

在现代电力系统管理中,实时监测输电线路的状态至关重要,这不仅有助于提前预防故障,而且能优化能源分配和增强系统的可靠性。通用分组无线业务(General Packet Radio Service,GPRS)技术作为一种成熟的无线数据传输手段,为远程输电线路监测提供了一种有效的通信解决方案。文章设计基于GPRS技术的输电线路状态数据通信系统,重点分析系统的总体架构、GPRS通信模块的设计、数据管理与传输策略以及安全性与容错机制的构建,并阐述测试系统的方法及其效果。

基于GPRS技术的电力系统通信性能优化研究

文章针对电力系统中通用分组无线业务(General Packet Radio Service,GPRS)通信存在的传输时延较高、丢包率较高、吞吐量和信道利用率不足以及抗干扰能力不足的问题,提出一种基于GPRS技术的电力系统通信性能优化方法(GPRS-based Power System Communication Performance Optimization Method,GPRS-PSCOM)。该方法通过GPRS网络优化、数据流管理以及错误处理与纠正技术的有机结合,全面提升了电力系统通信的实时性、可靠性和安全性。实验结果表明,GPRS-PSCOM方法在降低传输时延、丢包率,提高吞吐量、信道利用率以及抗干扰能力等方面效果显著。

基于接地线电流法的电力电缆绝缘在线监测

为提高电力系统的安全性,将接地线电流法作为核心方法,设计电力电缆绝缘在线监测系统。采用通用分组无线业务/码分多址(General Packet Radio Service/Code Division Multiple Access,GPRS/CDMA)通信方式作为电力电缆绝缘在线监测系统的核心,建立电缆各条线路之间的通信连接。利用电流互感器(Current Transformer,CT)检测电缆电流变化情况,有利于提高绝缘在线监测系统的检测精度。将绝缘在线监测应用于电力系统,可为电力系统的后续发展提供依据。

通信技术在输配电监测与控制中的应用分析

随着电力系统的智能化转型,输配电实时监测与控制的需求日益增长,通信技术在此过程中扮演着重要角色。文章详细分析公网通用分组无线服务(General Packet Radio Service,GPRS)、5G通信技术以及无线专网在输配电监测与控制中的应用,并探讨这些技术存在的局限性,为电力系统的智能化转型提供坚实的理论支撑,确保电网运营的可靠性、安全性及高效性。

全路GPRS系统共用设备故障对行车业务的影响分析

针对近年来铁路GSM-R网络中偶发大面积进路预告、调度命令异常的问题,结合全路GPRS共用设备运用情况、GPRS组网、承载的铁路业务特点等开展研究。对各铁路局不同厂商核心网设备访问GPRS共用设备的业务逻辑进行分析,研究GPRS不同业务运用场景和运用机制,梳理GPRS共用设备主用节点设备故障或脱网对业务造成的影响、应及时采取的措施和优化手段等;结合GSM-R网络实际组网情况,研究数据网对承载全路GPRS业务的影响,分析业务消息的路由转接,进而针对可能发生的隐性故障,判断故障点及影响范围,将安全风险关口前移,有效提升GPRS故障应急处置水平,缩短故障延时和缩小影响范围,为共用设备主用节点退网检修、异地主备倒换测试等提供相关参考依据;提出全路数据网承载GPRS业务的维护建议和优化措施。

通信电源实时监测系统开发及应急预案研究

文章针对通信电源系统易受多种因素影响的特点,开发了一种基于高级精简指令集计算机机器(Advanced Reduced Instruction Set Computer Machines,ARM)核心控制芯片和通用分组无线业务(General Packet Radio Service,GPRS)数据传输单元(Data Transfer Unit,DTU)模块的实时监测系统。系统通过现场控制终端采集通信电源设备的运行状态信息,经模拟数字(Analog to Digital,AD)转换模块处理后,由ARM核心控制芯片发送至无线模块,最终传输至远程监控中心。此外,设计一套应急预案,包括应急预案设计原则、组织机构与职责、应急分级、启动条件与工作流程以及保障措施等,以应对电网大停电带来的经济损失。通过技术保障、装备保障、人员保障,实现抢修工作的快速响应,缩短断电时间,有效减少经济损失,确保生产生活不受影响。

铁路下一代通信承载网技术演进路径探索

为了全面评估IPv6技术在铁路行业中的潜在优势,首先对通信传输网、数据通信网和5G-R承载网的组网、业务需求、未来演进趋势进行分析;其次针对铁路下一代承载网对关键组网能力和业务承载能力的要求,分析切片分组网络(SPN)、IP无线接入网2.0版(IPRAN2.0)和分组增强型光传送网络(POTN)3种主流承载网技术的需求满足度,对比分析这3种技术在组网能力、性能指标、产业生态等方面的差异;着重分析IPv6段路由、网络切片、随流检测、应用感知网络等IPv6+特性在通信承载网中的应用需求,调查显示融合、灵活且松散耦合的产品和技术方案更适合铁路承载网的未来发展需求;最后分析使用IPRAN2.0技术建设下一代承载网过程中多网并存阶段的互通需求和解决方案。经分析论证得出结论:在IPv6网络方案中优选IPRAN2.0,待SPN标准及功能成熟后可选用SPN。

Realization of remote update technology for embedded equipment based on μC/OS-Ⅱ

Aiming at the inaccessible problem of remote embedded devices update and maintenance, this paper presents a method using general packet radio service （GPRS） to achieve update based on the embedded real-time operating system （RTOS） μC/OS-Ⅱ. It introduces architecture of the system first. And then it uses LPC1768 chip as the central processing unit, SIM900A module for data transmission, and SST25VF016B to store the data. To ensure accuracy of the data transmis- sion, cyclic redundancy code （CRC） is adopted. The software uses fixed bootstrap and mutable update program, and thus the embedded devices can still normally start in case of update failure. Finally, high stability and extensive adaptability of the system are verified by experimental data.

基于3S技术联合的农田墒情远程监测系统开发

农田墒情信息是现代农业实施精准施肥、精确灌溉的重要科学依据。为了实现快速准确地采集墒情信息,研究开发了基于3S(GPS/GIS/GPRS)技术联合的农田墒情远程监测系统。该系统主要由农田信息监测网络节点和远程服务器组成,在小范围内由传感器节点基于ZigBee通讯协议组成无线传感器网络,在大尺度上通过网关节点集成GPS网络,利用GSM/GPRS网络实现与Internet的信息交互,完成了墒情数据的自动采集、无线传输和准确定位。设计了太阳能自供电的长寿命无线传感器节点和网关节点,开发了服务器端农田墒情信息管理系统软件,实现了Web方式下的参数远程设置和信息实时监测。该系统的设计开发为农田墒情信息监测和分析决策提供了有效的工具。

基于零序功率方向的中性点不接地系统在线故障定位

提出了基于零序功率方向的在线故障定位方法,判断故障和非故障路径上零序电压和零序电流的相位差,利用全球定位系统(GPS)的秒脉冲为相位获取提供基准,借助通用分组无线业务(GPRS)传送相位信息,实现配电网在线故障定位。物理模型实验证明了该方法的有效性。

基于GPRS网络的输电线路绝缘子污秽在线遥测系统

研制了一种基于通用分组无线业务(GPRS)通信网络的监测线路绝缘子污秽状况的新系统,简述了其系统构成、技术特点和应用效果。并给出了监测分机的硬件和软件的具体设计方法。借助在线监测系统对运行绝缘子进行了一系列的试验,结果表明,当不同污秽等级的绝缘子的环境湿度增大时,其泄漏电流增加幅度有很大差异;专家软件引入模糊控制算法,部分开放报警模型,提高了绝缘子污秽判断的准确性,从而及时指导绝缘子的清扫工作。

基于嵌入式系统的心电无线远程传输系统

研制了一套适用于远程急救或家庭远程监护的基于嵌入式处理器Intel SA-1110的心电无线远程传输系统.该系统硬件部分由数据采集模块、数据存储及显示模块、GPRS模块及嵌入式微处理器Intel SA-1110组成.数据采集模块负责心电的采集、滤波及A/D变换;数据存储和显示模块完成心电数据的存储、波形显示;GPRS模块实现心电信号的无线远程传输;Intel SA-1110控制全系统及各模块间的通讯;软件部分包括基于嵌入式操作系统WinCE开发的病人管理程序和基于Windows开发的远端心电服务器软件.在1天内5个不同时段进行数据传输实验,比较采集的心电信号与远程服务器接收的信号,误码率为零,传输速度为12.5～35 kb/s.