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
针对煤矿井下环境复杂,干扰源多,通信效率低下等难题,研究基于SIP协议和VoIP技术的煤矿应急广播监控系统。采用双向通信技术和动态抖动缓冲区技术增强抗干扰能力,优化信息传递机制。利用FreeSWITCH搭建电话软交换服务平台,结合Ozeki VoI...针对煤矿井下环境复杂,干扰源多,通信效率低下等难题,研究基于SIP协议和VoIP技术的煤矿应急广播监控系统。采用双向通信技术和动态抖动缓冲区技术增强抗干扰能力,优化信息传递机制。利用FreeSWITCH搭建电话软交换服务平台,结合Ozeki VoIP SIP插件实现语音信号高效传输。制定数据交互接口,实现与安全监控系统、人员定位系统、信息引导发布系统之间的融合联动。经现场试验表明,系统在日常多场景播报、应急广播、安全宣教等业务场景应用效果良好,规范矿工作业行为,有效提升煤矿整体安全水平。展开更多
基于5G高速率、低时延的特性,结合广播电视网络网际互连协议(Internet Protocol,IP)数据传输需求,提出一种融合深度强化学习与自适应阈值优化的IP数据封装方法。其基本原理是通过动态计算数据优先级、优化封装阈值及校验传输完整性等,...基于5G高速率、低时延的特性,结合广播电视网络网际互连协议(Internet Protocol,IP)数据传输需求,提出一种融合深度强化学习与自适应阈值优化的IP数据封装方法。其基本原理是通过动态计算数据优先级、优化封装阈值及校验传输完整性等,实现高效可靠的IP数据传输。实验结果表明,所提方法在服务质量(Quality of Service,QoS)保障成功率、封装效率、端到端时延及资源块利用率等方面显著优于传统数字视频广播-运动图像专家组(Digital Video Broadcasting-Moving Picture Experts Group,DVB-MPEG)方法,可为5G与广电网络深度融合提供技术支撑。展开更多
随着4K超高清技术的飞速发展及其在广播电视领域的广泛应用,4K转播车音频系统面临着前所未有的挑战与升级需求。在介绍基于网际互连协议的音频(Audio over Internet Protocol,AoIP)技术的基础上,提出一套基于AoIP架构的4K转播车音频系...随着4K超高清技术的飞速发展及其在广播电视领域的广泛应用,4K转播车音频系统面临着前所未有的挑战与升级需求。在介绍基于网际互连协议的音频(Audio over Internet Protocol,AoIP)技术的基础上,提出一套基于AoIP架构的4K转播车音频系统优化方案。测试结果表明,优化后的AoIP音频系统在信号容量、路由灵活性、同步精度及可靠性方面均表现出色,能够有效满足现代4K超高清节目制作的需求。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.
文摘针对煤矿井下环境复杂,干扰源多,通信效率低下等难题,研究基于SIP协议和VoIP技术的煤矿应急广播监控系统。采用双向通信技术和动态抖动缓冲区技术增强抗干扰能力,优化信息传递机制。利用FreeSWITCH搭建电话软交换服务平台,结合Ozeki VoIP SIP插件实现语音信号高效传输。制定数据交互接口,实现与安全监控系统、人员定位系统、信息引导发布系统之间的融合联动。经现场试验表明,系统在日常多场景播报、应急广播、安全宣教等业务场景应用效果良好,规范矿工作业行为,有效提升煤矿整体安全水平。
文摘基于5G高速率、低时延的特性,结合广播电视网络网际互连协议(Internet Protocol,IP)数据传输需求,提出一种融合深度强化学习与自适应阈值优化的IP数据封装方法。其基本原理是通过动态计算数据优先级、优化封装阈值及校验传输完整性等,实现高效可靠的IP数据传输。实验结果表明,所提方法在服务质量(Quality of Service,QoS)保障成功率、封装效率、端到端时延及资源块利用率等方面显著优于传统数字视频广播-运动图像专家组(Digital Video Broadcasting-Moving Picture Experts Group,DVB-MPEG)方法,可为5G与广电网络深度融合提供技术支撑。
文摘随着4K超高清技术的飞速发展及其在广播电视领域的广泛应用,4K转播车音频系统面临着前所未有的挑战与升级需求。在介绍基于网际互连协议的音频(Audio over Internet Protocol,AoIP)技术的基础上,提出一套基于AoIP架构的4K转播车音频系统优化方案。测试结果表明,优化后的AoIP音频系统在信号容量、路由灵活性、同步精度及可靠性方面均表现出色,能够有效满足现代4K超高清节目制作的需求。
