蜂窝网络数据业务模型的建立方法

马尔科夫随机过程是电路域业务模型的建立基础。本文首先阐述马尔科夫随机过程理论建立电路域模型业务模型的原理和方法,并指出该方法并不适用于基于信道共享的移动数据业务场景。然后,阐述了移动蜂窝网络的数据业务特征,并重新提出了一种新的数据业务模型,该模型结合了通信网络的实际性能和用户量,可以获得网络最佳在线用户数和最佳吞吐量,从而为移动数据业务的规划和优化奠定可靠的基础。     

香港运营商的HSPA+升级样板

网络下载速率的提升使得用户更乐意使用数据业务,带动全网数据业务吞吐量增加,反过来又对网络下载速率和性能提出了更高要求。香港移动通讯(CSL)在早前推出HSPA服务之后,其用户的数据业务量猛增了几乎40倍,给网络     

流量业务用户感知的评估方法分析

本文探寻移动数据业务网络参数、性能指标与用户体验之间的关系,分析影响用户感知的因素,提出用现网数据量化用户体验的方法。对于移动数据业务,我们将从移动用户体验,即感知质量QoE的角度出发,分析现网数据业务特征,研究影响业务QoE关键因素,抽象数据业务类型,探索评估各类业务用户感知质量评估的理论依据。     

HSPA空分复用技术的室内外场测试

1 前言 HSPA技术具有高突发性、高可靠性和高吞吐量等特性,适合数据传输。HSPA技术广泛应用后,TD—SCDMA网络数据业务由移动语音业务转型为移动数据业务,用户对TD—SCDMA网络数据业务的使用由简单的下载、上网浏览网页等,升级为高质量的视频流、无线视频会议电话、在线音乐、电子邮件等业务,这些实时类的交互和基于IP的数据业务对网络容量提出了新的要求。     

移动数据业务计费系统性能调优分析

本主要介绍了移动数据业务计费系统的结构和功能，对系统的各项性能指标进行了分析和评估，对系统性能调优的优化策略和使用效果进行了归纳。     

创新无止境 突破网络吞吐量的利器

根据原信产部预测，未来三年国内移动通讯市场新增用户将达到3亿，将继续保持高速增长的态势，同时，移动语音用户也将持续向移动数据用户转型。随着越来越多的用户加入到以视频下载、移动播客为代表的业务应用时，系统的吞吐量有可能成为数据业务深度发展的瓶颈。如何降低数据业务的每bit成本，如何提高网络吞吐量是运营商提供优质数据服务所面临的重要挑战。     

ZTE中兴 TD-HSPA MX倍速技术：提升网络吞吐量的利器

根据原信息产业部预测，未来三年斟内移动通信市场将继续保持高速增长的态势，新增用户将达到3亿户。同时，移动语音用户也将持续向移动数据用户转型。随着越来越多的用户加入到以视频下载、移动播客为代表的业务应用中，系统的吞吐量有可能成为数据业务深度发展的瓶颈。如何降低数据业务的每bit成本，以及如何提高网络吞吐量是运营商提供优质数据服务所面临的重要挑战。     

一种互操作协议性能评估方法

在异构网络环境下。互操作协议对应用系统具有重要意义，互操作协议的性能对应用系统的性能也起着举足轻重的作用．为确定应用系统性能瓶颈，必须评估互操作协议性能．本文提出了一种互操作协议性能评估方法．该方法针对实际应用系统中的互操作协议，提出符合实际的评估指标，对协议性能进行定性分析和定量分析．在定性分析中得出安全性、容错能力、可扩展性等性能指标．在定量分析中，建立仿真实验模型与排队论数学模型相结合的混合模型。得出网络带宽占用、响应时间与吞吐量等性能指标．综合这些指标，我们给出互操作协议性能评估的结果．     

HSDPA技术特点及其部署策略

HSDPA（High Speed Download Packet Access）即高速下行分组接入，它是3GPP在R5协议中为了满足上／下行数据业务不对称的需求而提出的一种技术。HSDPA基本上继承了3GPPR99定义的许多性能，且又大大地增强了移动数据传输下行链路的峰值速率和吞吐量并降低了传输时延，它把下行数据业务速率提高到10Mbiffs。该技术是WCDMAR99／R4网络提高下行容量和数据业务速率的一种重要技术。     

中兴通讯HSPA MX倍速解决方案

根据原信产部预测,未来三年国内移动通讯市场新增用户将达到3亿,将继续保持高速增长的态势,同时,移动语音用户也将持续向移动数据用户转型。随着越来越多的用户加入到以视频下载、移动播客为代表的业务应用时,系统的吞吐量有可能成为数据业务深度发展的瓶颈。如何降低数据业务的每bit成本,如何提高网络吞吐量是运营商提供优质数据服务所面临的重要挑战。     

一种流媒体集中存储系统设计与实现

从网络吞吐量、磁盘读写性能等关键指标上分析了流媒体集中存储的需求。并以此为基础设计实现了一种流媒体集中存储系统,结合实现过程中遇到的问题,着重围绕存储进程的管理模式、索引的建立、存储文件的分配与调度、存储介质的保护等几个关键点展开了讨论。     

Comparison of Performance of Packet Scheduling Algorithms in LTE-A HetNets

The concept of usage of heterogeneous networks (HetNets) is about improving the LTE system performance by increasing the capacity and coverage of the Macro cell. In this paper, a performance comparison of various packet scheduling algorithms such as Proportional Fair, Maximum Largest Weighted Delay First and Exponential/Proportional Fair is studied in detail in the HetNets environment. The key performance indicators such as throughput, packet loss ratio, delay and fairness are considered to judge the performance of the scheduling algorithms. Various strategies such as increasing the number of Pico cells in the cell edge were used in the simulation for the performance evaluation study. The results achieved through various simulations show that adding Pico cells to the existing Macros enhances the overall system performance in addition to the various scheduling algorithms implemented in Macros. For reader’s convenience, various types of graphs have been used to represent the simulation results to better understand the performance metrics of various scheduling algorithms. Simulation results shows that overall system gain has increased because of adding Picos and thereby providing better coverage in the cell edge areas and thereby increasing the capacity of the network to provide better quality of service.     

Randomly Ranked Mini Slots for Fair and Efficient Medium Access Control in Ad Hoc Networks

Ad hoc networks offer infrastructure-free operation, where no entity can provide reliable coordination among nodes. Medium access Control (MAC) protocols in such a network must overcome the inherent unreliability of the network and provide high throughput and adequate fairness to the different flows of traffic. In this paper, we propose a MAC protocol that can achieve an excellent balance between throughput and fairness. Our protocol has two versions: randomly ranked mini slots (RRMS) utilizes control-message handshakes similar to IEEE 802.11. Randomly ranked mini slots with busy tone (RRMS-BT) is the better performer of the two, but requires a receiver busy tone. The protocol makes use of granule time slots and sequences of pseudorandom numbers to maximize spatial reuse and divide the throughput fairly among nodes. We demonstrate the performance of this protocol using simulation with fixed and random topologies and show that these results are robust to difficult network configurations and unsynchronized clocks. We further develop novel metrics of long-term and short-term fairness for rigorous performance evaluation. Our simulation results include a detailed comparison between the proposed protocol and existing protocols that have been shown to excel in terms of throughput or fairness     

传感器网络环境监测时间序列数据的高斯过程建模与多步预测

Accessing to the optimal network was an effective way of ensuring the efficiency of network resources utilization and improving network performance.An access point selection mechanism based on cross-layer awareness for cognitive networks(CN_CLA)was proposed.Firstly,a cross-layer cognitive framework was constructed for obtaining the primary evaluation parameters that influence the performance of network access.Secondly,the fuzzy theory was applied for evaluating the access network performance comprehensively,and the weights in each layer were optimized using the quantum genetic algorithm,and then the access point was selected intelligently.Simulation results show that the proposed method chooses reasonable access networks without intervention of users.Furthermore,it is superior to the traditional methods,including the link capacity scheme,H_RSSI_S and AS_FTM,in terms of throughput,delay,session completion rate,packet loss and other performance indicators.     

单小区模型的掉话率分析

掉话率是无线通信网络中最重要的关键性能指标(KPI)之一,本文分析了中国移动在讨论网络性能评估方法时提出的3个不同的掉话率计算公式,通过建立一个单小区的模型,使用一些合理的假设和分析,从理论上确定了一个最为准确的计算公式.     

Clustered Zigbee networks with data fusion: Characterization and performance analysis

In this paper, we analyze the performance of clustered Zigbee wireless sensor networks (WSNs) with data fusion. Performance indicators at both physical (probability of decision error) and network (network transmission rate, throughput, aggregate throughput, delay, and network lifetime) layers are considered. Data fusion is carried out at the access point (AP) and, in clustered configurations, also at the clusterheads, which act as intermediate fusion centers (FCs). The goal of this paper is to shed light on the joint impact of topology and data fusion on the network performance. The presented results, mainly obtained through Opnet-based simulations, show clearly that the operational point of a Zigbee WSN with data fusion lies over a characteristic multi-dimensional surface, whose shape remains the same regardless of the number of nodes in the network. The existence of this peculiar surface highlights fundamental performance trade-offs in Zigbee networks.     

波分复用系统加密技术研究

波分复用系统是将多个独立的光波耦合复用到一根光纤中传输,从而更有效地提供带宽,让IP、ATM、SDH等数据通过统一的光纤层传输的系统。波分复用系统在改善网络性能的同时,也给网络的安全带来了一定的隐患。文中针对波分复用（WDM）自身特点及所面临的安全威胁,提出基于WDM的加密技术研究思路,为实现对WDM／OTN／ASON网络综合数据业务的安全保密奠定了基础。     

移动流媒体端到端质量管理研究

本文在介绍移动流媒体网络结构与业务特征的基础上,提出了多角色参与情况下流媒体业务的端到端质量管理方法,特别对移动流媒体端到端层次质量管理体系和流媒体质量评估指标进行了探讨和建议,文中还针对指标量度性的两个重要解决手段--关联分析方法和测量技术进行了总结.     

基于中继协作的认知无线电性能研究

频谱感知是认知无线电技术的关键。协作频谱感知能够充分利用网络资源,提高网络中认知用户的检测概率,降低认知用户的虚警概率。基于两个认知用户之间的中继协作,研究了协作频谱感知的感知性能与吞吐量的折衷。仿真结果表明：中继协作的频谱感知方法能够使得在充分保证对授权用户不造成干扰即检测概率一定时,能够有效地降低认知用户感知授权用户的虚警概率,缩短＂弱＂认知用户获得最大吞吐量的最优感知时间,提高其最大吞吐量,并提高认知系统的最大吞吐量。     

Secrecy enhancement in two-hop DF relaying system under hardware impairment

In this paper, we investigate joint jammer selection and network coding for secrecy enhancement under transceiver hardware impairment. We propose two protocols of joint jammer selection and network coding (SCCJ-OJS and SCCJ-MiJS) to improve secrecy outage and throughput performance compared with a protocol without cooperative jamming (SCC). For performance evaluation, we derive exact closed-form expressions for the secrecy outage probability (SOP) and throughput performance of the three protocols. Our analysis is substantiated via Monte Carlo simulation. The results show that the SCC protocol is nearly in an outage state when the eavesdroppers are close to the source and/or relays, while the SCCJ-OJS and SCCJ-MiJS protocols still improve the performance compared with the SCC protocol in this strict case. In addition, transceiver hardware impairments can degrade the eavesdropping channel: the performance of the SCC protocol increases linearly with hardware impairment level, whereas SCCJ-OJS and SCCJ-MiJS protocol performance is enhanced at a low level and experience a minor decrease at a high level of hardware impairment. Finally, the theoretical results match the simulation results well.