As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels...As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels,broadcasts are carried out on multiple channels.Accordingly,channel selection and collision avoidance are challenging issues to balance the efficiency against the reliability of broadcasting.In this paper,an anticollision selective broadcast protocol,called acSB,is proposed.A channel selection algorithm based on limited neighbor information is considered to maximize success rates of transmissions once the sender and receiver have the same channel.Moreover,an anticollision scheme is adopted to avoid simultaneous rebroadcasts.Consequently,the proposed broadcast acSB outperforms other approaches in terms of smaller transmission delay,higher message reach rate and fewer broadcast collisions evaluated by simulations under different scenarios.展开更多
Broadcast is an important operation in many network protocols. It is utilized to discover routes to unknown nodes in mobile ad hoc networks (MANETs) and is the key factor in scaling on-demand routing protocols to larg...Broadcast is an important operation in many network protocols. It is utilized to discover routes to unknown nodes in mobile ad hoc networks (MANETs) and is the key factor in scaling on-demand routing protocols to large networks. This paper presents the Ad Hoc Broadcast Protocol (AHBP) and its performance is discussed. In the protocol, messages are only rebroadcast by broadcast relay gateways that constitute a connected dominating set of the network. AHBP can efficiently reduce the redundant messages which make flooding-like protocols perform badly in large dense networks. Simulations are conducted to determine the performance characteristics of the protocol. The simulation results have shown excellent reduction of broadcast redundancy with AHBP. It also contributes to a reduced level of broadcast collision and congestion.展开更多
Group key exchange protocols are basic protocols to provide privacy and integrity in secure group communication. This paper discusses the security of one type of group key exchange protocols and defines the kind of pr...Group key exchange protocols are basic protocols to provide privacy and integrity in secure group communication. This paper discusses the security of one type of group key exchange protocols and defines the kind of protocols as broadcaster group protocols. It points out two attacks on this kind of protocols. The first attack can be avoided by using fresh values in each action during one session of the group protocol. The second attack should be related with concrete application. It also proposes a dynamic key agreement protocol as an example of solutions at the last part of the paper.展开更多
It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in citie...It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in cities or canyons,in which the signal will be sheltered by big buildings or mountains.In order to solve this problem,an Internet-based broadcast network has been proposed to utilize the infrastructure of the Internet to broadcast the augmentation information of satellite navigation system,which is based on application-layer multicast protocols.In this paper,a topology and position aware overlay network construction protocol is proposed to build the network for augmentation information of satellite navigation system.Simulation results show that the new algorithm is able to achieve better performance in terms of delay,depth and degree utilization.展开更多
Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve ...Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve the IP multicast model but employ join/leave messages to track local group membership for broadcast LANs (shared medium LANs) was proposed in this paper. We describe the implementation requirements of the new mechanism and compare it to existing one, demonstrating that join/leave approach is uniformly superior for the environment of broadcast LANs.展开更多
为提高水电厂监控系统性能,本文研究提出了水电厂监控系统新型通信模型。论文基于以太网的开放系统互联参考模型OSI(Open Systems Interconnection Reference Model)架构,分析了目前水电厂监控系统普遍采用单播和广播相结合的以太网通...为提高水电厂监控系统性能,本文研究提出了水电厂监控系统新型通信模型。论文基于以太网的开放系统互联参考模型OSI(Open Systems Interconnection Reference Model)架构,分析了目前水电厂监控系统普遍采用单播和广播相结合的以太网通信的优点和不足,分析了传输控制协议TCP(Transmission Control Protocol)模型架构和报文发送、握手连接及断开连接过程,阐述了用户数据报协议UDP(User Datagram Protocol)网络模型的特点,提出了改进UDP网络协议安全性的措施。本文系统对比分析了单播、组播和广播网络信息传输模型的特点,探讨了单播、组播和广播网络信息传送模型与TCP和UDP相结合的以太网网络通信模型的特点。基于对TCP网络协议模型在广播中的可靠性与实时性研究,本文提出了一种UDP与IP组播技术相结合的新型水电厂计算机监控系统网络通信模型,可大幅提高监控系统通信实时性和可靠性,并通过实际工程应用案例进行验证和分析,为水电厂计算机监控系统通信模型建立提供新的选择,具有巨大的应用前景和推广价值。展开更多
近几年,由于媒体融合的发展以及A地区广播电台的技术进步,A台原有的总控系统功能模块在逐步扩充,已经不能很好地满足广电行业今后发展需要。为了更好地整合现有信息,提高科技服务的支持水平,保证播出安全,构建覆盖广播音频、可视广播视...近几年,由于媒体融合的发展以及A地区广播电台的技术进步,A台原有的总控系统功能模块在逐步扩充,已经不能很好地满足广电行业今后发展需要。为了更好地整合现有信息,提高科技服务的支持水平,保证播出安全,构建覆盖广播音频、可视广播视频、网络流媒体接入、处理、调度、分发及监控等功能为一体的广播融媒体播控中心,是广播发展融媒化的必然要求。基于此,详细阐述了A台网际互联协议化音频(Audio over Internet Protocol,AoIP)广播电视融媒体传播控制中心的设计细节及特色。展开更多
基于电影和电视工程师协会(The Society of Motion Picture and Television Engineers,SMPTE)ST 2110标准,详细阐述总控建设、超高清同播技术、高动态范围(High Dynamic Range,HDR)技术、视音频系统、控制网络技术以及时钟同步技术等多...基于电影和电视工程师协会(The Society of Motion Picture and Television Engineers,SMPTE)ST 2110标准,详细阐述总控建设、超高清同播技术、高动态范围(High Dynamic Range,HDR)技术、视音频系统、控制网络技术以及时钟同步技术等多个方面的关键内容,为电视制播系统的网际互连协议(Internet Protocol,IP)化转型提供理论支持和实践指导。展开更多
江苏省广电有线信息网络股份有限公司无锡分公司设计了一套基于数字视频广播(Digital Video Broadcast,DVB)+网际互连协议(Internet Protocol,IP)的数字电视全业务融合播出平台模型。在此基础上,根据项目部署地的实际需求,设计并完成项...江苏省广电有线信息网络股份有限公司无锡分公司设计了一套基于数字视频广播(Digital Video Broadcast,DVB)+网际互连协议(Internet Protocol,IP)的数字电视全业务融合播出平台模型。在此基础上,根据项目部署地的实际需求,设计并完成项目一期工程的数字电视前端系统。详细介绍全系统包含卫星电视节目的信号接收、无锡地区电视节目的 IP传输、自办节目播出、电子节目单(Electrical Program Guide,EPG)开机广告、信号复用、信号调制以及信号分配等功能。展开更多
传统广播与新媒体的融合,提升了广播媒体的传播力和影响力,在更好地满足受众需求的同时,带来了较大的经济效益。广播融媒直播系统基于全媒体设计,搭建了内容生产、发布和融合信号汇聚的全网际互连协议(Internet Protocol,IP)技术平台,...传统广播与新媒体的融合,提升了广播媒体的传播力和影响力,在更好地满足受众需求的同时,带来了较大的经济效益。广播融媒直播系统基于全媒体设计,搭建了内容生产、发布和融合信号汇聚的全网际互连协议(Internet Protocol,IP)技术平台,依托“云+端”前后期一体化制播方案,打通了全媒体生产各流程的物理壁垒,将广播、视频直播、点播发布等各种传播形态进行深度融合,打造多元化跨界联动广播的新格局。文章主要介绍重庆广播电视集团(总台)实施的广播融媒直播及总控系统,以展示网际互联协议化音频(Audio over Internet Protocol,AoIP)和云技术在广播融媒直播系统的应用实践。展开更多
网络协议通话(Voice over Internet Protocol,VoIP)技术作为一种新兴的音频传输技术,在广播播控领域引起广泛的关注。首先,对AoIP的技术特征进行深入分析,指出其基于网际互连协议(Internet Protocol,IP)网络的音频传输和处理特点。其次...网络协议通话(Voice over Internet Protocol,VoIP)技术作为一种新兴的音频传输技术,在广播播控领域引起广泛的关注。首先,对AoIP的技术特征进行深入分析,指出其基于网际互连协议(Internet Protocol,IP)网络的音频传输和处理特点。其次,详细阐述在广播播控中应用AoIP技术的诸多优势。再次,从机房同步系统、实时信息同步、统一管理系统以及一网多传等方面,探讨AoIP技术在广播播控中的具体应用。最后,强调AoIP技术对广播播控未来技术构架的深远影响,进一步推动广播播控系统朝着数字化、网络化方向发展,促进系统的智能化、自动化,为广播播控技术的发展注入新的活力。展开更多
近年来,广播电视技术转型向网际互连协议(Internet Protocol,IP)化发展的进程逐渐加快,基于IP架构的电视技术系统必将取代传统串行数字接口(Serial Digital Interface,SDI)架构,成为未来电视技术的发展方向。对以互联网协议网关(Interne...近年来,广播电视技术转型向网际互连协议(Internet Protocol,IP)化发展的进程逐渐加快,基于IP架构的电视技术系统必将取代传统串行数字接口(Serial Digital Interface,SDI)架构,成为未来电视技术的发展方向。对以互联网协议网关(Internet Protocol Gateway,IPG)作为关键设备搭建“SDI+IP”混合架构系统的设计方案进行深入分析,阐述电视技术系统从SDI向IP技术转型过程中尽可能实现平稳过渡的思路。展开更多
网际互连协议(Internet Protocol,IP)化网络作为一种新兴的传输技术,正在改变传统的电视制作和播出模式。基于此,概述了IP化技术的相关概念,分析了IP化技术的数字编码和分组传输机制,阐述了IP化技术在推动电视制播融合方面的作用,提出...网际互连协议(Internet Protocol,IP)化网络作为一种新兴的传输技术,正在改变传统的电视制作和播出模式。基于此,概述了IP化技术的相关概念,分析了IP化技术的数字编码和分组传输机制,阐述了IP化技术在推动电视制播融合方面的作用,提出了电视制播IP化网络的分层架构,解析了IP化核心网和接入网的组成,以及软件定义网络(Software Defined Network,SDN)在IP化网络中的控制作用。展开更多
文摘As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels,broadcasts are carried out on multiple channels.Accordingly,channel selection and collision avoidance are challenging issues to balance the efficiency against the reliability of broadcasting.In this paper,an anticollision selective broadcast protocol,called acSB,is proposed.A channel selection algorithm based on limited neighbor information is considered to maximize success rates of transmissions once the sender and receiver have the same channel.Moreover,an anticollision scheme is adopted to avoid simultaneous rebroadcasts.Consequently,the proposed broadcast acSB outperforms other approaches in terms of smaller transmission delay,higher message reach rate and fewer broadcast collisions evaluated by simulations under different scenarios.
基金the National '863' High-Tech Programme of China (No. 863- 300- 01-03-99 ).
文摘Broadcast is an important operation in many network protocols. It is utilized to discover routes to unknown nodes in mobile ad hoc networks (MANETs) and is the key factor in scaling on-demand routing protocols to large networks. This paper presents the Ad Hoc Broadcast Protocol (AHBP) and its performance is discussed. In the protocol, messages are only rebroadcast by broadcast relay gateways that constitute a connected dominating set of the network. AHBP can efficiently reduce the redundant messages which make flooding-like protocols perform badly in large dense networks. Simulations are conducted to determine the performance characteristics of the protocol. The simulation results have shown excellent reduction of broadcast redundancy with AHBP. It also contributes to a reduced level of broadcast collision and congestion.
基金Supported by the National Natural Science Foun-dation of China (90104005 ,60473023) the National High Tech-nology Research and Development Programof China (863 Program)(2002AA41051)
文摘Group key exchange protocols are basic protocols to provide privacy and integrity in secure group communication. This paper discusses the security of one type of group key exchange protocols and defines the kind of protocols as broadcaster group protocols. It points out two attacks on this kind of protocols. The first attack can be avoided by using fresh values in each action during one session of the group protocol. The second attack should be related with concrete application. It also proposes a dynamic key agreement protocol as an example of solutions at the last part of the paper.
基金supported by National High Technical Research and Development Program of China (863 Program) under Grant No. 2009AA12Z322
文摘It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in cities or canyons,in which the signal will be sheltered by big buildings or mountains.In order to solve this problem,an Internet-based broadcast network has been proposed to utilize the infrastructure of the Internet to broadcast the augmentation information of satellite navigation system,which is based on application-layer multicast protocols.In this paper,a topology and position aware overlay network construction protocol is proposed to build the network for augmentation information of satellite navigation system.Simulation results show that the new algorithm is able to achieve better performance in terms of delay,depth and degree utilization.
文摘Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve the IP multicast model but employ join/leave messages to track local group membership for broadcast LANs (shared medium LANs) was proposed in this paper. We describe the implementation requirements of the new mechanism and compare it to existing one, demonstrating that join/leave approach is uniformly superior for the environment of broadcast LANs.
文摘为提高水电厂监控系统性能,本文研究提出了水电厂监控系统新型通信模型。论文基于以太网的开放系统互联参考模型OSI(Open Systems Interconnection Reference Model)架构,分析了目前水电厂监控系统普遍采用单播和广播相结合的以太网通信的优点和不足,分析了传输控制协议TCP(Transmission Control Protocol)模型架构和报文发送、握手连接及断开连接过程,阐述了用户数据报协议UDP(User Datagram Protocol)网络模型的特点,提出了改进UDP网络协议安全性的措施。本文系统对比分析了单播、组播和广播网络信息传输模型的特点,探讨了单播、组播和广播网络信息传送模型与TCP和UDP相结合的以太网网络通信模型的特点。基于对TCP网络协议模型在广播中的可靠性与实时性研究,本文提出了一种UDP与IP组播技术相结合的新型水电厂计算机监控系统网络通信模型,可大幅提高监控系统通信实时性和可靠性,并通过实际工程应用案例进行验证和分析,为水电厂计算机监控系统通信模型建立提供新的选择,具有巨大的应用前景和推广价值。
文摘近几年,由于媒体融合的发展以及A地区广播电台的技术进步,A台原有的总控系统功能模块在逐步扩充,已经不能很好地满足广电行业今后发展需要。为了更好地整合现有信息,提高科技服务的支持水平,保证播出安全,构建覆盖广播音频、可视广播视频、网络流媒体接入、处理、调度、分发及监控等功能为一体的广播融媒体播控中心,是广播发展融媒化的必然要求。基于此,详细阐述了A台网际互联协议化音频(Audio over Internet Protocol,AoIP)广播电视融媒体传播控制中心的设计细节及特色。
文摘基于电影和电视工程师协会(The Society of Motion Picture and Television Engineers,SMPTE)ST 2110标准,详细阐述总控建设、超高清同播技术、高动态范围(High Dynamic Range,HDR)技术、视音频系统、控制网络技术以及时钟同步技术等多个方面的关键内容,为电视制播系统的网际互连协议(Internet Protocol,IP)化转型提供理论支持和实践指导。
文摘江苏省广电有线信息网络股份有限公司无锡分公司设计了一套基于数字视频广播(Digital Video Broadcast,DVB)+网际互连协议(Internet Protocol,IP)的数字电视全业务融合播出平台模型。在此基础上,根据项目部署地的实际需求,设计并完成项目一期工程的数字电视前端系统。详细介绍全系统包含卫星电视节目的信号接收、无锡地区电视节目的 IP传输、自办节目播出、电子节目单(Electrical Program Guide,EPG)开机广告、信号复用、信号调制以及信号分配等功能。
文摘传统广播与新媒体的融合,提升了广播媒体的传播力和影响力,在更好地满足受众需求的同时,带来了较大的经济效益。广播融媒直播系统基于全媒体设计,搭建了内容生产、发布和融合信号汇聚的全网际互连协议(Internet Protocol,IP)技术平台,依托“云+端”前后期一体化制播方案,打通了全媒体生产各流程的物理壁垒,将广播、视频直播、点播发布等各种传播形态进行深度融合,打造多元化跨界联动广播的新格局。文章主要介绍重庆广播电视集团(总台)实施的广播融媒直播及总控系统,以展示网际互联协议化音频(Audio over Internet Protocol,AoIP)和云技术在广播融媒直播系统的应用实践。
文摘网络协议通话(Voice over Internet Protocol,VoIP)技术作为一种新兴的音频传输技术,在广播播控领域引起广泛的关注。首先,对AoIP的技术特征进行深入分析,指出其基于网际互连协议(Internet Protocol,IP)网络的音频传输和处理特点。其次,详细阐述在广播播控中应用AoIP技术的诸多优势。再次,从机房同步系统、实时信息同步、统一管理系统以及一网多传等方面,探讨AoIP技术在广播播控中的具体应用。最后,强调AoIP技术对广播播控未来技术构架的深远影响,进一步推动广播播控系统朝着数字化、网络化方向发展,促进系统的智能化、自动化,为广播播控技术的发展注入新的活力。
文摘网际互连协议(Internet Protocol,IP)化网络作为一种新兴的传输技术,正在改变传统的电视制作和播出模式。基于此,概述了IP化技术的相关概念,分析了IP化技术的数字编码和分组传输机制,阐述了IP化技术在推动电视制播融合方面的作用,提出了电视制播IP化网络的分层架构,解析了IP化核心网和接入网的组成,以及软件定义网络(Software Defined Network,SDN)在IP化网络中的控制作用。
