Resource management in LEO satellite networks

To provide truly global coverage needed by increased Personal Communication Services (PCS), a new generation of mobile satellite networks has been proposed. These low Earth orbit (LEO) mobile satellite networks handle multimedia traffic and can be used for non-real-time as well as real-time service to remote areas. Due to the many handoffs, resource management and connection admission control are important tasks for fair bandwidth sharing and QoS guarantees. Because the total link capacity has to be divided among several carriers and given the limited buffer capacity of the ATM switch, resource management is vital. It ensures the ability of the network to provide users with their negotiated QoS while protecting the network and the end-systems from congestion. We introduced a simple connection admission control (CAC) priority policy based on the delay and cell loss requirements for the investigated types of traffic. We took into account the handoff status of the satellite beams involved. Thus, we propose an onboard buffer architecture with separated buffers for new calls and intra-satellite handoff calls. The priority scheme applied is as follows: highest priority is given to CBR, followed by rt-VBR, nrtVBR and ABR.     

移动视频业务的EQoS方案及跨层资源管理模型

在分析4G网络的链路特性、视频业务对网路资源的要求和3GPP移动网路QoS方案的基础上,针对移动视频业务在未来ICT网络中的应用特点,提出了移动视频业务扩展QoS（EQoS）方案和基于EQoS方案的跨层资源管理模型。前者引入了移动视频业务细化衡量标准,有利于移动视频业务质量指标的量化;后者在保持原有网络分层模型的基础上,通过EQoS模块实现了跨层无线资源管理。     

Fairness based channel borrowing strategy in multimedia LEO satellite communications

A novel bandwidth allocation strategy along with a connection admission control technique was proposed to improve the utilization of network resources. It provides the network with better quality-of-service (QoS) guarantees, such as new call blocking probability (CBP) and handoff call dropping probability (CDP) in multimedia low earth orbit (LEO) satellite networks. Simulation results show that, compared with other bandwidth allocation schemes, the proposed scheme offers very low call dropping probability for real-time connections while, at the same time, keeping resource utilization high. Finally we discussed the fairness for the borrowed nonreal-time connections under three different channel borrowing methods. Translated from Journal on Communications, 2006, 27(8): 10–17 [译自: 通信学报]     

New dynamic routing algorithm based on MANET in the LEO/MEO satellite network

The features of low earth orbit/medium earth orbit (LEO/MEO) satellite networks routing algorithm based on inter-satellite link are analyzed and the similarities between satellite networks and mobile Ad Hoc network (MANET) are pointed out. The similar parts in MANET routing protocol are used in the satellite network for reference. A new dynamic routing algorithm based on MANET in LEO/MEO satellite networks, which fits for the LEO/MEO satellite communication system, is proposed. At the same time, the model of the algorithm is simulated and features are analyzed. It is shown that the algorithm has strong adaptability. It can give the network high autonomy, perfect function, low system overhead and great compatibility. __________ Translated from Journal on communications, 2005, 26(5): 50–62 (in Chinese)     

一种有效的802.16 BWA系统MAC层QoS框架

IEEE 802.16系列标准定义了WiMAX的无线空中接口,尽管标准详细的定义了MAC层信号机制,但并没有一套完整的资源管理调度机制,而资源管理和调度是影响QoS性能的重要部分.本文首先简要介绍了IEEE 802.16协议,分析了其QoS机制的主要内容,包括带宽的请求分配机制,准人和调度机制等.然后提出了一套有效的QoS框架,主要包括准入控制策略和上行调度策略.为了让不同业务的QoS得到保证,文章重点探讨了多优先级公平队列算法(MPFQ),通过这套机制,可以为不同级别的业务提供不同等级的Qos服务.     

Simulation study of QoS guaranteed ATM transmission for futurepower system communication

The asynchronous transfer mode (ATM) will support communication services with both constant and variable bit rate, for example, data, voice, video transmissions and, of particular note, multimedia applications combining those service components. However, many problems are required to be solved in order to apply this technique to an electric power company's network. Electric power companies are required to transmit very important information, such as information regarding electric power control. The transmission of this important information is required to have very high quality. Therefore, if the important information and the general information were switched in the same manner, the stringent QoS (quality of service) required for the important information could not be guaranteed. The authors examine the QoS of future utility communications which include ATM-native teleprotection signals, inter-LAN data communications and video conference communications. First, they propose a more accurate model which can be expressed by a multi-state Markovian process for computer data communication traffic. Second, the implementation of a priority control scheme in an ATM switch is proposed to guarantee the QoS of important power system communications. Finally, computer simulations are used to clarify the effectiveness of priority control and the feasibility of future ATM-based utility telecommunication networks     

ASAR: An ant-based service-aware routing algorithm for multimedia sensor networks

Aimed at three basic services (event-driven, data query and stream query), the paper presents a QoS routing model for multimedia sensor networks. Moreover, based on the traditional ant-based algorithm, we propose an ant-based service-aware routing (ASAR) algorithm. The ASAR chooses suitable paths to meet diverse QoS requirements from different kinds of services, thus maximizing network utilization and improving network performance. Finally, extensive simulation is conducted to verify the effectiveness of our solution and we give a detailed discussion on the effects of different system parameters. Compared to the typical routing algorithm in sensor networks and the traditional ant-based algorithm, our ASAR algorithm has better convergence and significantly provides better QoS for multiple types of services in the multimedia sensor networks. __________ Translated from Acta Electronica Sinica, 2007, 35(4): 705–711 [译自: 电子学报]     

河南省电力数据网IP业务在ATM网络中的传输

摘要： 河南省电力数据网中的IP业务，充分利用ATM网络所具有的服务质量(QoS)保证这一特点，进行管理信息系统（MIS）、电力市场技术支持系统(PMOS)及电能量计费系统(TMS)等IP业务的传输。文中详细描述了在ATM网络中所采用的传输方式、各业务的具体接入方案、传输效果以及业务传输的安全性，依靠IP技术和ATM技术的综合发展解决了电力系统中的一些特殊应用问题。     

电力通信ATM网络中的QoS技术

介绍了ATM网络中的端到端QoS技术的概念,分析了QoS定义的基本参数、ATM针对不同QoS提供的不同业务,以及QoS在ATM网络中的实现方法;提出了电力通信网中数据按ATM业务类划分的方法,指出在电力通信中采用QoS技术的必要性。     

Adaptive bandwidth framework for provisioning connection-level QoS for next-generation wireless cellular networks

The next generation of wireless cellular networks is expected to support real-time multimedia services with different classes of traffic and diverse bandwidth requirements. Bandwidth is a scarce resource in wireless networking that needs to be carefully allocated amid competing connections with different quality of service (QoS) requirements. In this paper, an adaptive framework for supporting multiple classes of multimedia services with different QoS requirements in wireless cellular networks is proposed. The framework combines the following components: (1) a threshold-based bandwidth allocation policy that gives priority to handoff calls over new calls and prioritizes among different classes of handoff calls by assigning a threshold to each class; (2) an efficient threshold-type call admission control (CAC) algorithm; and (3) a bandwidth adaptation algorithm (BAA) that dynamically adjusts the bandwidth of ongoing multimedia calls to minimize the number of calls receiving lower bandwidth than they had requested. Numerical results show that the proposed adaptive multimedia framework outperforms existing non-adaptive schemes in terms of the handoff call dropping probability and effective utilization.     

MPLS体系、性能及应用

就MPLS的产生背景，MPLS标签，MPLS流量工程，MPLS VPN应用等展开叙述，MPLS的问世可以保证如语音传送，视频服务，多媒体信息服务传输等应用业务按各应用的特性正确予以传送。MPLS网络中数据的传输告标签引导，标签是固定长度的，无结构的值，采用MPLS流量工程可以避免引起网络阻塞，为用户提供更好的服务。在Cisco IOS网络中，MPLS虚拟专用网提供了发展和管理第3层VPN骨干服务的能力。     

Three generations of cellular wireless systems

Advances in cellular communication technology have resulted in improved capacity, higher data rates and better quality of service (QoS). Many first and second-generation systems have been deployed and currently offer a range of predominantly voice-oriented services. Third generation cellular systems have been proposed with the goal of providing a seamless integration of mobile multimedia services into a single global network infrastructure. These systems are all summarized in a table     

平流层通信及其相关技术的应用前景

平流层通信兼有地面无线通信和同步卫星及低轨卫星通信的优点,具有传输时延短、容量大、覆盖区域广、承载业务丰富、相关技术应用领域广泛等诸多优点,将能成为兼容固定和移动业务的新一代无线通信系统.文章分析了该技术在电力通信系统和应急领域、输变电设施监测、电力工程建设中通信保障等方面的应用前景,并首次提出和探讨了近空间太阳能发电及应用的设想和概念.     

基于智能光网络系统的配用电业务承载方案研究

配用电无源光通信网络是连接10 kV及0.4 kV设备的通信基础设施,具有高效、稳定、安全等特点。针对配电领域业务分布范围广、安全形势严峻、光纤资源规模大、运维抢修难度高等难题,设计配用电多业务综合承载及安全防护方案。提出一种光网络智能管理系统,能够实现光纤资源标签电子化、运维抢修智能化目标。基于该智能系统自动生成网络拓扑信息,研究并提出了一种面向多业务的QoS(服务质量)路由策略。通过仿真分析可知,该策略采用的群智能优化算法可为特定业务提供端到端QoS最优转发路径,保障业务的通信QoS需求,收敛速度较快,提升了通信网对电力业务的承载能力。     

Predictive call admission control for multimedia streaming in CDMA cellular environments

Third-generation (3G) wireless networks based on code-division multiple access (CDMA) have been engineered to provide mobile users with voice as well as advanced packet data services. Support of Internet-based multimedia streaming services is considered a critical factor for future deployment of such networks. Provisioning streaming services in a dependable way, however, requires supporting data transmission at relatively high data rates while maintaining session quality during both intracell and intercell user movements. In this paper, an adaptive bandwidth allocation and admission control scheme is proposed for managing network resources for a streaming service. Streaming requests are assumed to be served by an adaptive server capable of choosing suitable video streaming parameters (e.g., video resolution, frame rate, and encoding parameters) in response to possible requests from the wireless network to vary the currently allocated bandwidth. The devised admission control scheme exploits a priori knowledge of user mobility patterns to minimize the risk of running into an overload condition after acceptance of a new multimedia streaming connection. The obtained simulation results show that, compared to a nonpredictive admission control scheme, the proposed scheme achieves a lower forced-termination probability and higher throughput, while consuming less base-station transmission energy.     

跻身未来的电力线通信:（七）PLC组网方案及应用

在分析电力线通信网络(PLC—NET)的特点和应用优势的基础上，提出了PLC—HLAN，PLC—VPN和PLC—AN等3种组网方案；在描述PLC—HLAN的家电控制等服务的同时，给出了总线式家庭网络的硬件组成，分析了网络的MAC子层的CSMA／CD及应用层的CAL协议的应用；在多种PLC—VPN的应用中，以自动抄表系统为例，给出了其组网的具体实现，包括网络的数据节点、集中和路由器的结构；在PLC—NET与电信网、计算机网的业务融合中，给出了PLC—AN的结构以及三网融合的接入方式，其中包括传输技术质量保证体系和相应的应用协议等。     

解决IP服务质量的综合方案及其应用

为了使IP网能满足音频、视频等实时业务的要求．研究在IP网上对不同业务提供相应的服务质量(QoS)保障是很重要的。文中重点对资源预留协议(RSVP)、综合服务(IntServ)以及区分服务(DiffServ)等几种QoS方案进行分析和讨论，并提出两个合成方案，即IntServ与DiffServ结合以及IP融入ATM的模型，可以解决网络中的延迟问题，实现网络资源的共享，并阐述了如何在电力通信网中利用MPLS技术传送关键业务。     

ATM技术与发展

异步转移模式（ATM）作为宽带综合业务数字网（BISDN）的转移模式,实现了网络与业务无关的特性,因而得到了迅速发展。文中介绍了ATM技术的核心概念,着重阐述了ATM技术的发展,包括在智能网、无线网络中的应用,以及如何在ATM网络上运载IP技术,并就IP与ATM技术的争议提出其见解。     

一种基于策略和NSIS的端到端QoS保障框架设计

本文在分析了IETF所提出的COPS（公共开放策略服务）协议和NSIS（下一代信令）协议的基础上,提出了一种基于策略和NSIS的全IP网络端到端QoS保障框架PN-e2eQoS,该框架能够实现对全网端到端路径的资源监控,使得数据流在基于不同QoS机制的网络之间建立和维护时,对QoS要求进行统一映射处理,从而达到了端到端QoS保障的目的。同时本文也详细定义了该框架下的面向发送端和面向接收端的信令交互过程。     

卫星通信中媒体接入控制协议的研究

媒体接入控制协议设计的基本目标是协调包的传输,实现高的信道吞吐量,低的传输时延,低复杂度的控制算法,信道的稳定性,协议的可扩展性和信道的再配置性。本文对卫星通信中的MAC协议进行了概括,分类和性能分析,并且研究了一组性能优越的混合式协议。最后针对下一代宽带卫星网络支持的业务特点,提出了一种适合多业务的高轨卫星媒体接入控制协议。对于恒定比特率的业务(CBR)采用固定分配的方式;对于实时/非实时可变率业务(rt/nrt-VBR)采用选择性轮询预约和捎带预约相结合的按需分配和加权自由分配的方式;对于非限定比特率业务(UBR)采用自由分配的方式。通过分析表明,协议在时延和吞吐量性能上能取得好的性能。