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Multimedia stream service provided by broadband wireless networks has emerged as an important technology and has attracted much attention. An all-IP network architecture with reliable high-throughput air interface makes orthogonal frequency division multiplexing access (OFDMA)-based mobile worldwide interoperability for microwave access (mobile WiMAX) a viable technology for wireless multimedia services, such as voice over IP (VoIP), mobile TV, and so on. One of the main features in a WiMAX MAC layer is that it can provide'differentiated services among different traffic categories with individual QoS requirements. In this article, we first give an overview of the key aspects of WiMAX and describe multimedia broadcast multicast service (MBMS) architecture of the 3GPP. Then, we propose a multicast and broadcast service (MBS) architecture for WiMAX that is based on MBMS. Moreover, we enhance the MBS architecture for mobile WiMAX to overcome the shortcoming of limited video broadcast performance over the baseline MBS model. We also give examples to demonstrate that the proposed architecture can support better mobility and offer higher power efficiency. 相似文献
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Xi Zhang Qinghe Du 《Communications Magazine, IEEE》2007,45(8):62-70
In this article we propose a cross-layer design model for multimedia multicast/broadcast services to efficiently support the diverse quality of service requirements over mobile wireless networks. Specifically, we aim at achieving high system throughput for multimedia multicast/broadcast while satisfying QoS requirements from different protocol layers. First, at the physical layer, we propose a dynamic rate adaptation scheme to optimize the average throughput subject to the loss rate QoS constraint specified from the upper-layer protocol users. We investigate scenarios with either independent and identically distributed (i.i.d.) or non-i.i.d. fading channels connecting to different multicast receivers. Then, applying the effective capacity theory at the data link layer, we study the impact of the delay QoS requirement (i.e., QoS exponent) on the multimedia data rate of mobile multicast/broadcast that our proposed scheme can support. Also presented are simulation results which show the trade-off among different QoS metrics and the performance superiority of our proposed scheme as compared to the other existing schemes. 相似文献
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《Communications Magazine, IEEE》2007,45(8):52-53
The six articles in this special section cover various aspects of mobile multimedia broadcasting involving physical layer (PHY), medium access control (MAC), cross-layer modeling and design, security, and services. The articles are summarized here. 相似文献
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In recent years, multimedia content broadcasting via satellite has attracted increased attention. The satellite digital multimedia broadcasting (S-DMB) system has emerged as one of the most promising alternatives for the efficient delivery of multimedia broadcast multicast service (MBMS). The design of an efficient radio resource management (RRM) strategy, especially the packet scheduling scheme, becomes a key technique for provisioning multimedia services at required quality of service (QoS) in S-DMB. In this article, we propose a novel cross-layer packet scheduling scheme that consists of a combined delay and rate differentiation (CDRD) service prioritization algorithm and a dynamic rate matching (DRM)-based resource allocation algorithm. The proposed scheme considers multiple key factors that span from the application layer to the physical layer, aiming at simultaneously guaranteeing diverse QoS while utilizing radio resources efficiently under the system power and resource constraints. Simulation results demonstrate that the proposed cross-layer scheme achieves significantly better performance than existing schemes in queuing delay, jitter, and channel utilization. 相似文献
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Unified Radio Network for Broadcasting and Broadband Wireless Access [Advances in Mobile Multimedia]
Weiwei Wang Changjia Chen Yunbao Zeng Zihua Guo Wenchao Ma Xuemin Shen 《Communications Magazine, IEEE》2007,45(8):54-61
In this article we propose a unified radio network architecture, broadband wireless multimedia (BWM), which integrates broadcasting service and broadband wireless access service at both the application and physical layers. A simple, flexible, and comprehensive radio resource management framework is developed for the unified radio network. It is shown that the proposed radio network architecture has many advantages over existing ones. In addition, the new architecture is currently being considered in China for the system level design. 相似文献
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刘建伟 《信息安全与通信保密》2001,(6):45-48
本文根据L.Harn提出的修正EIGamal签名方案和Rabin公钥加密体制,提出了数字移动通信网中一种高效的认证与密钥分配方案.与[6]的方案相比,新方案具有以下改进(1)由于采用了修正EIGamal签名方案,用户在预备阶段的计算量有所降低.(2)在实时呼叫建立阶段,网络的计算负荷有所减少.(3)方案中没有采用单钥体制,因此降低了方案实现时的成本.分析结果表明,该方案不仅具有较低的计算复杂度,而且具有很高的安全性. 相似文献
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MBMS的引入对于现有的蜂窝系统是一种有效的补充,可在现有网络上增加和改善一些功能实体,为用户提供更多的服务。文章介绍了TD—SCDMA系统的MBMS系统架构,对组网技术进行了研究,并提出了可行的组网方案。 相似文献
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Multicast and broadcast services in WiMAX are downlink point-to-multipoint access services optimized for transmission of a common set of multimedia data packets to a group of users. This capability enables low-cost delivery of large volumes of popular contents (e.g., for video/audio streaming and file sharing) in a mobile network. The MCBCS framework in WiMAX allows multicast/broadcast of data in a radio channel that is time shared with unicast services. In a single-frequency network, where MCBCS transmissions are synchronized or coordinated across BSs in the designated service area, the mobile stations can use macro-space diversity to improve achievable data rates and also maintain service continuity and power saving across cells with minimal interaction with the network. 相似文献
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A New Paradigm for Mobile Multimedia Broadcasting Based on Integrated Communication and Broadcast Networks 总被引:1,自引:0,他引:1
《Communications Magazine, IEEE》2008,46(7):126-132
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IPTV over WiMAX: Key Success Factors, Challenges, and Solutions [Advances in Mobile Multimedia] 总被引:1,自引:0,他引:1
The advances in broadband Internet access and scalable video technologies have made it possible for Internet Protocol television (IPTV) to become the next killer application for modern Internet carriers in metropolitan areas. With the recent release of IEEE 802.16d/e (worldwide interoperability for microwave access or WiMAX), broadband wireless access (BWA) is envisioned to further extend IPTV services to a new application scenario with wireless and mobility dimensions. It is a very strategic but challenging leverage for a carrier to glimpse the potential of IPTV by using WiMAX as the access network. Challenges are posed for IPTV over WiMAX due to multicasting under a diversity of fading conditions. A cross-layer design framework based on a novel two-level superposition coded multicasting (SCM) scheme is introduced. Simulation results show that much improved video quality is achievable with our approach. 相似文献
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移动自组网中基于多跳步加密签名 函数签名的分布式认证 总被引:26,自引:1,他引:26
移动自组网Manet(Mobile Ad Hoc Network)是一种新型的无线移动网络,由于其具有网络的自组性、拓扑的动态性、控制的分布性以及路由的多跳性,所以,传统的安全机制还不能完全保证Manet的安全,必须增加一些新的安全防范措施.本文探讨了Manet所特有的各种安全威胁,提出了一种基于多跳步加密签名函数签名的安全分布式认证方案,即将移动密码学与(n,t)门槛加密分布式认证相结合,并采用了分布式容错处理算法和私钥分量刷新技术以发现和避免攻击者假冒认证私钥进行非法认证以及保护私钥分量和认证私钥不外泄. 相似文献
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Naccache等人首次提出了批数字签名验证方案,但是C.H.Lim,P.J.Lee成功地对它进行CP攻击。本文是基于L.HARN总结的18种ELGamal型签名算法,指出它们中能实现批验证方案的通用规则。总共有12种可以被改变成DSA型数字签名算法以用于批验证,它们可以抵抗接收者的攻击。 相似文献
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分析了Ad Hoc网络中DSR按需路由发现原理及黑洞攻击原理,针对DSR路由协议面临的黑洞攻击问题,提出了一种基于JYH聚合签名算法的路由记录认证机制,新方案在DSR路由请求和路由应答消息中定义了路径证明属性,并设计了与之适应的输入签名算法和输出验证算法;最后,采用形式化逻辑SVO方法对该路由记录认证机制的安全性进行了分析。分析表明,提出的路由记录认证机制可以有效抵御针对DSR路由协议的黑洞攻击。 相似文献
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移动RFID系统是指利用植入RFID读写芯片的智能移动终端,获取标签中的信息,并通过移动网络,访问后台数据库,获取相关信息。然而,由于移动RFID系统的无线通信环境和无可视性读写,带来了很多安全隐患,已经成为制约移动RFID发展的重要因素,针对此问题,在分析了移动RFID网络构成及其安全隐患后,提出了一种基于相互认证的安全协议,该协议引入了一个第3方服务器来为移动读写器和后台数据库提供签名密钥,并且利用椭圆曲线加密体制(ECC)对信息进行签名验证,最后分析表明该协议可以为移动读写器与后台数据库提供安全的通信环境,以应对各种攻击。 相似文献