GSM网络掉话率指标优化分析

话音业务的掉话率是GSM网络的关键指标,本文主要分析了掉话产生的原因,总结了优化掉话率指标可使用的手段,并提出了持续改善掉话率指标的新方法。     

降低GSM网络掉话率的几种方法

近几年来,移动通信的蓬勃发展,也对营运者提出了新的要求:网络应具有较好的覆盖及通话质量。网络通话质量好坏的一个具体体现是TCH的掉话率。本人根据工作实际情况,介绍了降低GSM网络TCH掉话率的几种方法。     

创建分析模板快速查找CDMA掉话原因

掉话率是评价CDMA网络性能的一个重要准则。在CDMA优化中,掉话率专题优化往往借助路测数据来分析判断。文章介绍了创建分析模板快速查找掉话原因的思路。通过分析各种掉话现象所对应的路测数据中重要参数的不同特点,论述了创建分析模板的具体方法。     

无线市话网络掉话的评估和优化

从剖析掉话机理入手，在分析了网络掉话特点的基础上，通过网络话务数据评估出影响掉话率的主要因素，同时指出改善掉话率指标的有效优化方法。     

影响HO FAIL的因素及原因分析

CDMA蜂窝移动通信系统的掉话率是衡量系统性能的一个重要标准,而切换失败（Hand Off Fail）在很大程度上会引起掉话的产生,从而导致掉话率的上升。深刻了解、分析CDMA系统中HO FAIL（Hand OffFail）的具体原因,能帮助网络优化人员对网络出现的问题进行及时的处理分析,提高优化的效率。     

通过优化承载机制提升CS域掉话率问题研究

随着我国WCDMA网络的日臻完善,3G智能终端用户的普及,用户在畅享优质网络时终端处于并发业务成为新常态,并发业务由于PSRAB速率调整及信道迁移等原因,所导致的掉话概率会远高于传统单CS业务,通过理论分析在网络并发业务时控制信道迁移并进行适当限速,可以降低并发业务掉话率.文章以CS域业务掉话率为切入点,通过对并发业务特性进行分析,探索通过优化DRBC策略改善CS域掉话率的方法,从而实现网络CS域掉话率的改善.     

影响HO FAIL的因素及原因分析

CDMA蜂窝移动通信系统的掉话率是衡量系统性能的一个重要标准,而切换失败(Hand Off Fail)在很大程度上会引起掉话的产生,从而导致掉话率的上升。深刻了解、分析CDMA系统中HO FAIL(Hand OffFail)的具体原因,能帮助网络优化人员对网络出现的问题进行及时的处理分析,提高优化的效率。     

软交换割接后掉话率升高的解决方案

在GSM网络运行中，掉话现象是用户投诉热点，好的网络一般要求掉话率低于2％。随着GSM网络的日益成熟，如何降低掉话率是各运营商、设备商所关注的热点问题。主要讨论了掉话率以及如何设置交换与无线设备影响掉话的定时器，针对软交换工程割接后掉话率升高的问题提出了解决方案并进行实施，取得了良好的效果。     

WCDMA系统中PS掉话的一种原因分析及改进措施

在WCDMA系统中，PS业务的掉话率是一项衡量网络性能的重要指标。文中将对不同场景下的PS掉话率进行摸底测试，并对引起PS业务掉话的一大原因进行分析，找到了UE活性实例检测机制的不完善之处，提出了修改UE实例活性检测机制的改进方案，以降低系统整体的掉话率。     

浅析PHS掉话率网优的"标、本、药"

掉话率是衡量PHS网络质量的一项重要指标,降低掉话率是日常网优工作的难点。本文详细分析了引起掉话的各种原因,对如何治理掉话问题全面进行了探讨。     

Performance Comparison of Overlay and Peer Models in IP/MPLS over Optical Networks

We study the connection establishment of label switched paths (LSPs), and compare the LSP blocking performance of the overlay and peer models in IP/MPLS over optical networks. We consider two dynamic routing algorithms for the establishment of LSP connections, of which one is for the overlay model and the other is for the peer model. Our investigations on two typical network topologies, namely NSFNET and ARPA2 networks, show that the number of add/drop ports (or transceivers) on optical cross-connects (OXCs) has a significant impact on the LSP blocking performance for both models. We show by computer simulation that in each case, there is a threshold value for the add/drop ratio, which can achieve almost the best blocking performance. This threshold value remains virtually unchanged as the traffic load varies, but it does depend on the network topology and the number of wavelengths per fiber. This will then indicate the number of add/drop ports to be used so that one can achieve a near optimal blocking performance without incurring unnecessarily excessive network costs. Our investigations reveal that the peer model achieves a much better blocking performance than the overlay model when the number of add/drop ports is relatively high, but that this is not always true when the number of add/drop ports is small.     

移动GSM网络寻呼成功率参数优化

移动通信的网络质量越来越受到关注,运营商对网络性能指标的稳定性要求越来越高,尤其是涉及到用户感知的指标,例如寻呼成功率、接通率、掉话率等,都提出了很高的要求。文章对影响用户感知的重要指标寻呼成功率进行了分析。从分析影响GSM网络寻呼成功率的原因人手,找到寻呼成功率的参数优化方法。通过无线寻呼参数的优化,使寻呼成功率明显提高,达到预期的目的,提高用户感知。     

Performance analysis of RTS/CTS scheme in WLAN with the impact of bit errors

To estimate the system performance of RTS/CTS scheme in an error‐prone WLAN channel, this paper proposes a new three‐dimensional Markov model, which considers the impact of bit error on all kinds of frames, and both station short retry limit and long retry limit. The system performance parameters including saturation throughput, packet drop probability, drop time, and average delay are derived using the new Markov model. By comparing the numerical results with simulation results, the model is proved to be more accurate than previous work. The numerical results show that the channel bit error rate has a significant impact not only on system performance, but also on the sensitivity of other system parameters including network scale, channel data rate, and packet length. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of a high performance heat Sink Based on screen-fin technology

In this paper, a novel high-performance heat sink based on screen-fin technology is described. The structural features of the heat sink are presented. The apparatus to measure both the pressure drop and heat transfer performance are described. Correlation equations of friction factor and Colburn-j factor as a function of screen-fin orientation, coolant properties and flow rate through the mesh are formulated. A semi-empirical model is used to predict the heat exchanger pressure drop, thermal performance and to design prototype heat sinks. Prototypes are built and tested. By screen-fin technology, the best performance of this kind of heat sink with external dimensions: 76.2-mm-wide, 63.5-mm-deep with 38.1-mm-high screen-laminate fins is 4.3W//spl deg/C at 62.3-Pa pressure drop of air flow through the heat sink.     

AMR Packing／Unpacking参数优化

Packing和Unpacking的过程是AMR／FR与AMR／HR相互转化的一个过程,即内切换速率转化。现网中Packing／Unpacking数多的小区通常小区内切换失败率高,增加掉话风险,同时由于Packing数通常大于Unpacking数,造成Packing／Unpacking数多的小区半速率比例偏高。本文研究的出发点是希望通过对Packing／Unpacking相关机制和参数进行研究,通过合理设置相关参数减少不必要的Packing／Unpacking数,减少掉话风险和半速率占比。     

Mobility Management UAV-based Grouping routing protocol in flying ad hoc networks for biomedical applications

Wireless body area networks play a vital role in the medical field by saving human lives. It senses the human body condition and transmits it to the respective doctors. The faster the communication, the sensed data can be transmitted faster and the patients in emergency can be treated on time. Therefore, to increase the speed of communication, Unmanned Aerial Vehicles (UAV) are used in biomedical applications. In this flying ad hoc network, there is a possibility of link failure due to the high mobility of UAV. To overcome this issue, a new routing protocol, Mobility Management UAV-based Grouping (MMUG), for biomedical data transmission from one ground station to another via UAV is suggested in this research. The UAV creates the grouping system based on the coverage range of the group head. Group head selects the node that lies closer to the ground station. Group head continuously monitors the mobility of the unmanned aerial vehicles that lie in the coverage range and thus helps to maintain the link stability. The mobility issue will be overcome by using this proposed scheme, and it manages the mobility. The mobility management helps to increase the network performance by increasing the delivery rate and throughput and reducing the drop rate and overhead. Simulation results show that this routing protocol achieves 86% delivery rate and 1.95 Mbps throughput and reduces the drop rate by 14%, control overhead by 23%, and routing overhead by 20%. Moreover, this model achieves higher network performance compared to the existing techniques.     

多权值神经元网络仿生模式识别方法在低训练样本数量非特定人语音识别中与HMM及DTW的比较研究

本文将基于多权值神经元网络的仿生模式识别方法用于连续语音有限词汇量固定词组识别的研究中,并将其识别效果与HMM方法及DTW方法进行了比较分析.以15个词组的词汇表做测试,通过调整这三种识别算法的参数,在它们的拒识率相同的情况下,针对参加训练的词汇,比较他们的错误识别率(某类误认为他类);针对未参加训练的词汇,比较他们的错误接受率(误认为某类).结果表明,在低训练样本数量的情况下,仿生模式识别方法能获得更好的识别效果.     

IP网络传输控制的性能评价标准研究

性能评价标准是进行网络传输控制机制和算法研究的一个非常重要的问题.由于传输控制本身的多目标性,导致了性能评价标准也需要同时考虑多项内容,即需要研究综合性能评价标准.本文通过讨论包括服务质量、服务数量和公平性在内的性能评价指标、性能评价的时间尺度和评价粒度等几个基本问题,针对不同的粒度,分别从有效性和公平性两个方面提出了相应的性能评价标准.在有效性方面,定义了规格化性能函数这一概念,把时延、丢包率等服务质量和服务数量统一在一起进行评价;在公平性方面,利用随机过程均值和方差的关系,以及Raj Jain公平指数的改进公式进行评价.     

GSM移动通信网络掉话解析

本文将全面分析GSM移动通信系统中导致各类掉话的原因。在移动通信中,掉话可分为两种形式：一类是在SDCCH信道上的掉话,一类是在TCH信道上的掉话。掉话率作为反映网络性能的一项重要指标,一直是网络优化工作关注的重点。