移动互联网的端到端QoS的几点思考

移动互联网是互联网与移动通信系统的融合与发展,随着移动互联网的高速发展,用户对移动场景下的移动互联网服务质量及有线网络的服务质量的要求越来越高,希望可以实现移动互联网的无延迟、无阻塞、高质量服务。但由于移动网络的资源及拓扑结构具备动态性,这就增加了实现移动互联网端到端QoS的难度。为实现移动互联网中端到端QoS,就需要在移动互联网体系结构的基础上,解决移动管理、移动QoS协议、无线资源管理、分组调度等关键技术。     

基于不同移动模型的移动自组网多播路由协议性能研究

为了研究移动自组网中多播路由协议在不同移动模型下的性能,选取随机路点移动模型、高斯马尔科夫移动模型和参考点组移动模型,将三种移动模型的移动场景加入到NS2中,对基于部分网络编码的实时多播协议PNCRM进行仿真.结果表明,PNCRM协议在随机路点移动模型和高斯马尔科夫移动模型中的数据包投递率明显高于参考点组移动模型,但是参考点组移动模型的总开销和端到端延时是最优的.这样我们就可以根据不同的性能指标要求选择合适的移动模型.     

基于NS2的航空白组网节点移动模型仿真研究

航空自组网是MANET-s在航空通信中的应用。对三种节点移动模型在航空自组网中的应用进行了仿真研究。利用NS2仿真平台,添加了随机走动移动模型和随机方向移动模型,建立了AANET的网络模型．编写了仿真场景,对三种节点移动模型在AANET中的性能进行了仿真分析。结果表明随机路点移动模型的性能最优,随机走动移动模型其次,随机方向移动模型最差。研究结果对航空自组网的研究和应用具有一定的参考价值。     

基于网络演算的无线自组网QoS性能确定上界研究

为保证无线自组网的服务质量(QoS),需精确求解其性能确定上界.对进入无线自组网节点的数据流进行漏桶管制,节点为数据流提供基于速率-延迟(rate-latency)模型的服务保障,在已有无线自组网链路吞吐量模型的基础上利用网络演算理论推导了无线自组网节点的积压数据上界、端到端数据流的延迟上界以及端到端数据流的延迟抖动上界模型.对网格形式拓扑的无线自组网,不同数据流的仿真结果都在数值计算的上界范围之内,表明基于网络演算理论的无线自组网的QoS性能上界模型具有较好的性能.     

移动自组网应用建模及无线收发器选用策略

移动自组网作为一种特殊的无线网络被越来越广泛的应用,随之也变得越来越复杂.所以不同的应用场景需要采用不同的配置来组建自组网,才能达到网络性能相对最优.其中网络连通性和能源问题成为重点需要考虑的因素.为了更加合理高效地组建自组网,本文定义了一种移动自组网应用模型,并采用此模型对自组网应用场景进行了分类,提出了一种组建自组网的方法,重点对无线收发器的选择进行了研究.     

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.     

爱立信将在巴塞罗那全球移动大会上演示手持终端设备上的端到端LTE呼叫

爱立信将在巴塞罗那举办的全球移动大会上。用手持移动终端设备进行端到端长期演进——系统架构演进（LTE／SAE）呼叫的演示。LTE／SAE代表了用户体验向前演进的下一个步骤，降低了网络延迟，提高了网络容量和吞吐量。该项技术预计将于2009年实现商用。该技术改善了移动视频、博客、高端游戏、     

基于业务特征的TDD-LTE端到端QoS参数研究

针对移动互联网快速发展对无线接入网的高带宽和业务质量需求,首先进行了常用的移动互联网业务研究分析;其次,依据业务特性、3GPP网络协议规范和本地已部署的TDD-LTE网络结构,提出了端到端QoS设置模型;最后,在商用网络上进行QoS 参数部署验证。研究结果表明：在典型高速率业务环境下,TDD-LTE单小区峰值调度用户数增加253.92%;在现网混合业务拥塞环境下,TDD-LTE 单小区峰值调度用户数增加81.80%。研究结果具备良好的行业应用性和推广性。     

华为WiMAX端到端解决方案引领移动宽带时代

华为端到端移动WiMAX解决方案在ITU世界电信展（ITUTELECOMWORID2006）上一经亮相就赢得众多关注。华为向参会观众全面展示了端到端移动WiMAX解决方案包括系列化基站、接入服务网关、多样化终端，统一的网管系统等，并演示了各种丰富的移动宽带业务。     

移动自组网路由协议在3G速率下性能分析

本文研究了两种典型的移动自组网路由协议AODV和DSR在3G速率下的性能,设置了各种仿真场景,在NS2仿真环境中对报文丢失率和端到端延迟进行了详细的仿真和比较。仿真结果表明在3G速率下AODV性能要优于DSR。     

A decomposition approximation for the analysis of voice/dataintegration

A closed-form decomposition approximation for finding the data performance in voice/data queuing systems is presented. The approximation is based on Courtois' (1977) decomposition/aggregation techniques and is applied to Senet hybrid multiplexing, movable boundary frame allocation schemes. The approximation is applied to both infinite and finite buffer systems. In the former case the approximation is valid only in the underload region and serves as an upper bound for the mean data queuing delay. In the finite buffer case it is valid for the whole data traffic range and is shown to improve as the number of channels increase, and deteriorates as the buffer size increases. For finite buffer systems upper and lower bounds for the decomposition approximation have also been derived. It is found that the lower bound is tight in the underload and low traffic region of the overload. In these same regions the decomposition approximation serves as a tight upper bound     

Queuing network models for delay analysis of multihop wireless ad hoc networks

In this paper we analyze the average end-to-end delay and maximum achievable per-node throughput in random access multihop wireless ad hoc networks with stationary nodes. We present an analytical model that takes into account the number of nodes, the random packet arrival process, the extent of locality of traffic, and the back off and collision avoidance mechanisms of random access MAC. We model random access multihop wireless networks as open G/G/1 queuing networks and use the diffusion approximation in order to evaluate closed form expressions for the average end-to-end delay. The mean service time of nodes is evaluated and used to obtain the maximum achievable per-node throughput. The analytical results obtained here from the queuing network analysis are discussed with regard to similarities and differences from the well established information-theoretic results on throughput and delay scaling laws in ad hoc networks. We also investigate the extent of deviation of delay and throughput in a real world network from the analytical results presented in this paper. We conduct extensive simulations in order to verify the analytical results and also compare them against NS-2 simulations.     

Delay constrained optimal resource utilization of wireless networks for distributed control systems

An optimal resource utilization framework to analyze the impact of end-to-end delay thresholds on the wireless network throughput is developed. In contrast to conventional networks where lumped transmission and queuing delays are used to model the end-to-end delay, the proposed framework models these delay components separately to analyze their relative contribution to the end-to-end delay when stringent delay thresholds are used. A 'log' utility maximization problem is formulated and its distributed implementation using dual decomposition is proposed. Our optimization results show that decreasing the delay threshold leads to larger contribution from the transmission delay to the end-to-end delay.     

一种基于聚合流的端到端统计时延界的新算法

为分析融合网络中聚合业务的端到端时延性能,提出一种基于聚合流的融合网络端到端统计时延界的新算法.该算法利用MGF(矩母函数)重新表征了网络端到端时延界的MGF形式的概率模型.数值分析结果表明了该算法的有效性和优越性,该算法很大程度上提高了独立统计复用,对融合网络性能评价具有参考意义.     

Data-flow in mobile edge computing networks: end-to-end performance analysis using stochastic network calculus

Mobile edge computing (MEC) networks can provide a variety of services for different applications. End-to-end performance analysis of these services serves as a benchmark for the efficient planning of network resource allocation and routing strategies. In this paper, a performance analysis framework is proposed for the end-to-end data-flows in MEC networks based on stochastic network calculus (SNC). Due to the random nature of routing in MEC networks, probability parameters are introduced in the proposed analysis model to characterize this randomness into the derived expressions. Taking actual communication scenarios into consideration, the end-to-end performance of three network data-flows is analyzed, namely, voice over Internet protocol (VoIP), video, and file transfer protocol (FTP). These network data-flows adopt the preemptive priority scheduling scheme. Based on the arrival processes of these three data-flows, the effect of interference on their performances and the service capacity of each node in the MEC networks, closed-form expressions are derived for showing the relationship between delay, backlog upper bounds, and violation probability of the data-flows. Analytical and simulation results show that delay and backlog performances of the data-flows are influenced by the number of hops in the network and the random probability parameters of interference-flow (IF).     

区分服务网络中确保业务端到端时延的接纳控制算法研究

该文提出了一种对区分服务网络中时延敏感业务进行接纳控制的SACiD(Service Admission Control in DiffServ)算法,它不仅保证用户业务的端到端时延不超过确定的上界,而且能比较充分利用网络资源。仿真结果表明,SACiD算法可以保证时延敏感业务的服务质量,而且其业务接纳率和带宽利用率接近综合服务网络中接纳控制算法的性能,但它的存储器需求却远小于它们。此外,SACiD算法运算简单,具有与区分服务一致的可扩展性,可以为区分服务网络的资源管理提供支持。     

Cross-Layer Design of 2D Queuing Model for Multi-hop Wireless Networks

Based on cross-layer design, a modified 2-dimensional queuing model (2DQM) is proposed in this paper to tackle the problem of end-to-end quality of service (QoS) metric calculation. This model exploits the traffic arrival process, multi-rate transmission in the physical layer and error recovery technology with the protocol of truncated automatic repeat request in the data link layer. Based on this model, QoS metrics of wireless links can be evaluated hop by hop. The model can be used in more realistic scenarios of multi-hop wireless networks, although the computational complexity of 2DQM is slightly higher compared with existing 1-dimensional queuing model. Simulation results indicate that the proposed model can estimate the end-to-end packet loss-rate and average delay more accurately than existing models, and a model based QoS routing algorithm can find routes with better QoS performance (with lower end-to-end packet loss-rate and delay).     

航空电子系统中FC网络的仿真和延迟估计

对采用单交换机光纤通道(FC)网络的航空电子系统进行了描述,建立了网络的排队模型.根据M/G/1模型对FC网络的队列长度、服务时间等参数进行了分析和估计.在OPNET平台下对4种周边节点数不同的FC网络进行了仿真;通过仿真分析了FC网络端到端延迟和网络节点数关系,并对评估的数学模型进行了修正;研究了网络中的延迟"抖动"...     

End-to-End Delay Evaluation for an Optical Transparent Packet Network

In this paper an all optical packet switching network is considered to provide transparent transport of information. To this end the evaluation of the end-to-end packet delay is performed by means of analytical tools. Bounds are proposed for the maximum packet delay and calculated by means of a simple additive formula that can be used for approximate end-to-end delay evaluation. Packetization and multiplexing delay at the access interface and queuing delay inside the nodes are considered as contributions to the whole packet delay. The obtained results shown that time transparency can be reached within suitable network design.     

Fundamental Limits of Full-Duplex Spectrum Sharing Under Peak Interference Power Constraint

Cognitive radio (CR) and full-duplex (FD) have received extensive attention and research due to their high spectrum efficiency, which can effectively solve the problem of low spectrum efficiency in current communication systems. Based on CR and FD techniques, in this paper, a FD spectrum sharing CR networks is considered, in which both secondary users (SU1 and SU2) are each equipped with dual antennas, one antenna is used to transmit signals, and the other antenna is used to receive signals at the same time and frequency. Under peak interference power and peak transmit power constraints, we analysis the ergodic sum capacity and the outage probability based on the FD spectrum sharing CR networks and the conventional spectrum sharing CR networks. Furthermore, under no peak transmit power constrain and perfect self-interference cancellation (SIC), based on the FD spectrum sharing CR networks and the conventional spectrum sharing CR networks, the closed-form expressions of the theoretical performance upper bound of the ergodic sum capacity and the outage probability are derived by two lemmas and four propositions. Accurate mathematical analysis display, under the same bandwidth, the upper bound of ergodic sum capacity for the full-duplex spectrum sharing CR networks is twice as much as the traditional spectrum sharing CR networks, and the FD spectrum sharing CR networks based on SU1, also has better performance upper bound on the outage probability than the traditional spectrum sharing CR networks. Simulations results also validate that, the FD spectrum sharing CR networks obtains better communication performance than the conventional spectrum sharing CR networks, especially when the mean of self-interference channel power gain is small. Finally, we also can see that the simulation performance upper bound is completely consistent with the theoretical analysis performance upper bound, whether in the FD spectrum sharing CR networks or the conventional spectrum sharing CR networks. So also verifies the correctness of the theoretical performance upper bound derivation.