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接入层PTN网络优化方案研究 总被引:2,自引:2,他引:0
针对接入层PTN网络优化的问题,本文提出了一种简单有效的接入层PTN优化方案。所提方案基于PTN接入环中选点升级的思想,相比传统优化方式缩短了建设路径和周期,且能有效利用现有传输资源,大幅提高接入网络的带宽和安全性。 相似文献
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使用网络准入控制技术对接入终端进行身份呢认证、安全检查、授权访问,只允许合法的、值得信任的终端接入网络.结合国家电网网络现状进行研究,提出一种针对物联网终端视频设备的准入控制的方案,从而提高网络的可用性和安全行. 相似文献
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嵌入式系统移动视频监控终端平台安全性 总被引:1,自引:1,他引:0
提出基于INTEL IXP425嵌入式系统的移动视频监控终端实现方案,通过CDMA1x移动通信接入网络,复用四路IP数据通道,实现了高速上行数据传输。在此基础上,提出采用可信计算平台模块(TPM)与强制访问控制(MAC)的终端平台安全方案。实际测试表明,此方案能够满足移动视频监控应用需求。 相似文献
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崔岩峰 《电信工程技术与标准化》2005,(10):48-50
3G业务的开展及网络部署已成为各运营商关注的焦点,3G网络的业务特征将对现有的传输网络提出更多的新需求,尤其对接入层网络影响较大.本文从3G网络业务需求特征出发,对接入层传输网络优化的几种方案进行比较分析,提出基于综合接入系统的3G业务传输解决方案. 相似文献
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针对3G网络在移动状态下传输高清视频画面会遇到画面质量差、卡阻等现象的问题,对4G网络移动多媒体传输进行了简要介绍。依托快速发展的4G网络,通过集成视频压缩、网络传输等关键技术,详细计算得出移动高清视频经过视频编码标准H.265压缩后可以在4G网络下高质高速的传输。在此基础上,构建了视频传输系统实现方案,重点阐述系统中移动多媒体服务器缓冲区的码率控制和适用于4G网络的RTP协议封包格式的2个衔接作用,可有效解决当前3G网络移动视频信号传输的质量问题。 相似文献
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A layered video coding scheme with its inherent cell loss resilience has been considered as a means for transporting reliably integrated video services over an asynchronous transfer mode (ATM) based network such as the broadband-ISDN. This paper presents some data concealment techniques that can be implemented in the coding of video data at the encoder, in the ATM adaptation layer (AAL) functionality of network realization and at the decoder to improve the performance of a layered codec under different conditions of video packet loss. The performance of these techniques are verified by software simulations. 相似文献
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Scalable video coding (SVC) has been standardized as an extension of the H.264/AVC standard. This paper proposes a practical real‐time transport protocol (RTP) packetization scheme to transport SVC video over IP networks. In combined scalability of SVC, a coded picture of a base or scalable enhancement layer is produced as one or more video layers consisting of network abstraction layer (NAL) units. The SVC NAL unit header contains a (DID, TID, QID) field to identify the association of each SVC NAL unit with its scalable enhancement layer without parsing the payload part of the SVC NAL unit. In this paper, we utilize the (DID, TID, QID) information to derive hierarchical spatio‐temporal relationship of the SVC NAL units. Based on the derivation using the (DID, TID, QID) field, we propose a practical RTP packetization scheme for generating single RTP sessions in unicast and multicast transport of SVC video. The experimental results indicate that the proposed packetization scheme can be efficiently applied to transport SVC video over IP networks with little induced delay, jitter, and computational load. 相似文献
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本文提出一种用于分布式视频点播服务系统的速率分配算法和实现框架。在考虑负载均衡与满足服务器带宽限制的前提下,速率分配能将以失真为度量的全局视频质量最优化。确定各服务结点的输出码率被建模成一个最优化问题:优化目标是最小化多个视频总失真,限制条件为最低可接受视频质量、服务器带宽限制以及发送速率对客户端TCP流量的友好性。根据优化算法的计算结果,视频节目使用可变码率编码,由多个视频分发服务器同时向客户端传输;同时服务器检测与客户端之间端到端链路的时变特性和估计网络拥塞情况,使优化速率分配结果适应网络状态的变化。本方案应用跨层设计的思想,将应用层视频质量建模为网络层参数的函数,当网络状态波动时,动态调整编码码率和发送速率以适应带宽变化,提前避免链路拥塞,降低接收端解码器丢包率,从而使总体视频质量得到提升。 相似文献
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Ilias Politis Lampros Dounis Tasos Dagiuklas 《Signal Processing: Image Communication》2012,27(8):814-826
This paper studies the impact of mobility management and seamless handover mechanisms on the perceived quality of video streaming applications. A seamless handoff scheme is proposed that incorporates IEEE 802.21 Media Independent Handover framework and a QoE-driven rate adaptation scheme, for both scalable and single layer coding. Quality of Experience (QoE) has been considered as an important parameter for network selection. The proposed scheme has been implemented and evaluated in a real test-bed network. Objective and subjective quality evaluation measurements for both H.264/AVC and H.264/SVC have been carried out. Through experimentation, QoE driven mobility of video streaming can be better maintained with H.264/SVC under the combined seamless handoff and rate adaptation functionality. 相似文献
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In this work, we propose a cross-layer solution to robust video multicast in erasure networks based on random linear network coding (RLNC) in the network layer and video interleaving (VI) in the application layer, and call it the joint RLNC-VI scheme. In the RLNC implementation, we partition one video coding unit (VCU) into several priority levels using scalable properties of H.264/SVC video. Packets from the same priority level of several VCUs form one RLNC generation, and unequal protection is applied to different generations. RLNC provides redundancy for video packets in the network layer and has proved to be useful in a multicast environment. Then, we propose a new packet-level interleaving scheme, called the RLNC-facilitated interleaving scheme, where each received packet corresponds to a new constraint on source packets. As a result, it can facilitate the RLNC decoding at the destination node. Furthermore, we study the problem of optimal interleaving design, which selects the optimal interleaving degree and the optimal redundancy of each generation. The tradeoff between delay and received video quality due to the choice of different VCUs is also examined. It is shown by simulation results that the proposed RLNC-VI scheme outperforms the pure RLNC method for robust video multicast in erasure networks. This can be explained by two reasons. First, the VI scheme distributes the impact of the loss (or erasure) of one VCU into partial data loss over multiple neighboring VCUs. Second, the original video content can be easily recovered with spatial/temporal error concealment (EC) in the joint RLNC-VI scheme. 相似文献
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组播技术的出现为基于P2P的视频会议系统提供了负载更小的开发方案,但在传统的组播技术支持下,分配到每台主机上的负载量依然可观。为解决突发负载问题,文中提出了一种基于主机性能评价的应用层组播算法,利用拓扑信息减少冗余数据在网络上传输,根据主机性能平衡负载分配,减轻主机负担。之后,在此组播算法之上,阐述了一种传统视频会议系统的优化实现方案。 相似文献
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一种改进的可分级视频编码方法及其网络传输研究 总被引:5,自引:0,他引:5
该文提出了一种改进的可分级视频编码方法。为了适应流媒体的分层传输要求,该方法通过对DCT系数量化残差的位平面编码产生视频流的增强层部分,其基本层码流由更多的子基本层组成,各子基本层通过宏块级DCT系数重排及VLC重组生成。同时,该文设计了一种针对该分层视频流数据的网络传输自适应不等重丢包保护(AUPLP)策略,在估计当前可利用带宽资源的基础上,实时调整不同层数据的保护力度,并控制传输截断的层数。仿真结果表明,与传统方法相比该文方案在低带宽时可获得平均1.2dB的编码增益,AUPLP的应用也大大改善了视频流媒体的传输质量。 相似文献
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针对数字网络视频监控系统的需求,设计一种基于MPEG-4网络视频服务器。使用基于MPG440的MPEG-4实时视频压缩卡压缩采集到的音视频数据,利用循环队列实现音视频数据的压缩,同时运用多线程技术以及传输机制解决网络数据的传输,从而有效克制了画面不清晰、音视频不同步、马赛克等现象,保证客户监看时音视频实时性和同步性。经过实验证明,该方案经济高效,可应用在多种需要音视频监控的场合。 相似文献
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This paper studies a reference network architecture for video information retrieval, based on hierarchical storage of the video segments and asynchronous transfer mode (ATM) transport capability on the long distance network. The storage associated to local switching nodes can be exploited in two complementary ways, either for caching the most requested video programs, and for decoupling the transmission speed on the long distance network from the natural playout speed of the video segments. We show that both approaches lead to a substantial increase of the load carried on the long distance network with a given service requirement. Moreover, we show that a greater efficiency is obtained when a suitable integration of the two approaches is considered 相似文献
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Reininger D.J. Dipankar Raychaudhuri Hui J.Y. 《Selected Areas in Communications, IEEE Journal on》1996,14(6):1076-1086
A scheme for delivery or variable bit-rate (VBR) video over asynchronous transfer mode (ATM) networks where bandwidth can be renegotiated during the duration of a call between the video source and the network is considered. Renegotiation can be initiated by either the video source or the network. The video bandwidth requirement is characterized by a usage parameter control (UPC) consisting, in general, of peak rate, burst length, and sustained rate. A baseline design is outlined where rate-control adjusts the source's rate while a new UPC is requested from the network. When granted, the new UPC allows the source to maintain its target quantization and delay requirements. Rate control epochs may be extended when the network blocks UPC requests or sets a lower UPC value to temporally deal with congestion. Simulation results are presented for VBR MPEG video. The results show that with a moderate renegotiation rate the scheme tracks the bandwidth requirements of the source. As a result, the video quality and bandwidth efficiency can be maintained 相似文献