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Low energy consumption is one of the main challenges for wireless video transmission on battery limited devices. The energy invested at the lower layers of the protocol stack involved in data communication, such as link and physical layer, represent an important part of the total energy consumption. This communication energy highly depends on the channel conditions and on the transmission data rate. Traditionally, video coding is unaware of varying channel conditions. In this paper, we propose a cross-layer approach in which the rate control mechanism of the video codec becomes channel-aware and steers the instantaneous output rate according to the channel conditions to reduce the communication energy. Our results show that energy savings of up to 30% can be obtained with a reduction of barely 0.1 dB on the average video quality. The impact of feedback delays is shown to be small. In addition, this adaptive mechanism has low complexity, which makes it suitable for real-time applications. 相似文献
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INTRODUCTION Low latency video transmission is very de manding in terms of the performance of all layers i the protocol stack. Over the last decade, research ha focused on enhancements of each individual laye without considering cross-layer interactions. Adapt ing video coding to the channel/network condition and technologies (and vice versa) (Girod et al., 2002 via the cross-layer exchange of information has onl recently been investigated. van der Schaar et al.(200 developed a cross-laye… 相似文献
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尤丽萍 《福建工程学院学报》2020,(6):598-603
为提高公路车辆的数据服务效率和通信服务的能量利用率,将分簇算法应用于实际环境的数据传输,提出一种新的传输机制。针对公路环境,应用分簇和数据聚合,进行了实时的双向数据协作传输在公路上的应用设计。仿真结果表明:在公路环境中,整合了分簇和数据聚合的数据传输机制能有效提高服务率、减少服务时延、提高吞吐量并减少能耗。 相似文献
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一种新的无线视频传输帧内刷新策略 总被引：1，自引：0，他引：1
首先分析了无线信道突发性出错和二阶Markov无线信道模型. 根据该模型和视频编码器的编码方式推导了突发性出错引起的帧内编码和帧间编码的信道失真. 然后提出了一种新的速率失真率(R-D)框架内的帧内刷新策略. 该策略一方面对无线视频传输系统的容错性能和编码效率进行了优化, 另一方面可有效阻止帧间错误传播, 减小信道失真. 在不同传输信道中的仿真结果验证了该策略在无线视频传输容错方面的性能改进. 相似文献
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本文提出了适用于物联网视频多跳中继无线通信的实现能量预估的网络层叠协同路由交互寻访技术。该技术的前提是采用遗传算法设计轮询步进优化估值模型,依据估值模型计算节点感知距离和节点能量,结合无线大容量信号编码解调码过程建立层叠协同交互寻访体系,优化簇内、簇头节点的传输效能,实现用户层、网络通信层和感知层层叠路由的交互协同。经软件仿真和数学矩阵对比,该技术可较好地满足物联网视频等大容量感知数据的传输与处理,而且可以充分利用物联网层叠资源特别是感知层与链路层受限的运算、存储和能量等资源。 相似文献
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结合空时OFDM和转换编码技术,提出了一种无线衰落信道下具有可分级转码能力的鲁棒视频传输方法.采用可分级转码器将高质量的MPEG-2压缩视频转换为低码率、低分辨率MPEG-4可分级码流来满足网络带宽和终端设备显示的要求.在接收端采用一种层干扰抑制算法,使得分层空时OFDM系统不同层的传输性能存在差异,从而使系统具有不对等保护能力.根据分级码流的重要程度不同,将转码输出的可分级码流分别由分层空时编码OFDM系统的不同层来实现视频的鲁棒传输.实验结果表明:在典型的随机突发错误的无线环境下,提出的具有可分级转码能力的系统的视频传输性能优于传统的非分级转码的视频传输系统. 相似文献
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误码率是评价数据传输设备及其信道工作质量的一个重要指标,而误码仪作为通信系统的可靠性测量工具,广泛用于传输设备的生产调试、检验以及日常维护维修,旨在完成一个高斯衰落信道下数字基带系统的实现及其误码率性能的测试。借助FPGA实验平台,通过Verilog语言在FPGA芯片上编程以实现数字基带信号的产生、星座映射、基带成型、信道、匹配滤波、判决、解映射、误码计算等模块,并通过FPGA的数码管显示误码率。 相似文献
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JEYARAJ Arulsaravana CHENG Liang EL ZARKI Magda 《浙江大学学报(A卷英文版)》2006,7(10):1690-1694
INTRODUCTION Increase in wireless system capacity through 3G services and innovative low bit rate video coding techniques have made it possible to have mobile multimedia services on hand-held systems. High quality real-time multimedia services are slowly be- ing deployed on hand-held systems. However large scale deployment at low cost is still to be realized due to technological challenges such as stringent power control under severely fading environments and the susceptibility of high qu… 相似文献
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INTRODUCTION With the development of novel wireless tech- nologies and increasing available bandwidth, multi- media applications over wireless networks become attractive for both businesses and end users. Fast de- ployment of Wi-Fi HotSpots, increase in wireless coverage of remote habitable areas (Wi-Max, or wireless mesh networks), improved data services over the 2G cellular systems and the long awaited debut of 3G wireless services offer many potential and inter- operable communicatio… 相似文献
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刘京中 《邢台职业技术学院学报》2004,21(1):45-47,77
如何提高数据传输的可靠性，实现实时通信是一个迫切需要解决的问题，也是现代数字通信设计者所面临的主要课题之一。本文提出一种修正型SWIHEC方案，该方案具有极低的误码输出，信息传输的连续性非常好，适合随机错误与突发错误并存的组合信道下全双工实时通信。 相似文献
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INTRODUCTION Streaming of multimedia data over the Internet has rapidly increased in recent years. All commercial applications and most research in video streaming use conventional hybrid video coding. To adapt the data transmission rate on the server to the varying bandwidth caused by congestion in the Internet or to different available bandwidths of different clients, the simulcast solution is widely applied (Balk et al., 2003; Feamster et al., 2001; Schierl and Wiegand, 2004). A larg… 相似文献
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INTRODUCTION Video multicasting over wireless local area net- work (WLAN) (IEEE Standard 802.11, 1997) enables the distribution of live or pre-recorded programs to many receivers efficiently. An example application is to redistribute TV programs or location-specific in- formation in hot spots such as airport. Users can watch their favorite TV programs on mobile devices while browsing the Internet. For enterprise applica- tions, an example is multicasting video of a lecture or trainin… 相似文献
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为了均衡传统分簇路由算法中的簇间传输能耗,减少簇首更换开销,提出基于最优化模型的能耗均衡分簇路由协议 opt_leach。将区域节点划分成大小相同的簇,均衡不同簇的簇内通信开销;簇间通信采用多种路由组合的方式通信,均衡簇间通信开销;簇内节点可以连续充当簇首,减少簇首更换开销。实验结果表明,与传统分簇路由算法相比,该算法可更好地实现能耗均衡,延长网络生存时间。 相似文献
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This paper introduces a novel robot for outer surface inspection of boiler tubes.The paper describes the hardware system,wireless communication strategy,communication procedure and system software of the robot.The WLAN technology is used in the robot.It solves the problem of shielding generated by iron boiler and 11Mbps bahdwidth made it possible for video and control steam real-time transmit within the same channel.Though TCP/IP protocol is tobust,serial server is a transparent channel but cannot detect error and retansmit the data.In order to improve the reliability of srial communication,a new communication protocol is proposed. 相似文献
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INTRODUCTION In typical video transmission systems, a video signal is compressed, and the resulting bit stream is transmitted over an error-prone channel. The errors may consist of symbol errors caused by fading, as observed for wireless channels, or packet erasures caused by congestion, as observed in the Internet. If a received video packet contains errors, then the portion of the video signal contained in the packet is lost and must be concealed. Error concealment schemes alone cannot … 相似文献
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CHAKARESKI Jacob 《浙江大学学报(A卷英文版)》2006,7(5):773-783
INTRODUCTION According to yearly statistics the demand for multimedia traffic over computer networks is con- stantly on the increase (Nielsen//NetRatings, http:// www.nielsen-netratings.com/). Therefore, it is inevi- table that situations where different media streams will need to share communication resources will be- come commonplace. In such cases, it would be of interest to optimize the overall performance of the network. In other words, resources should be allo- cated across the com… 相似文献
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在“国内本土潮流品牌”复兴的语境下,短视频媒介凭借媒介固有的沟通行动机制不仅促进了受众消费国货,还反向驱动了国货产品制作。短视频媒介平台顺应消费者民族中心主义,不断挖掘符合“Z世代”群体的消费审美的视频内容,进而建构了“国货消费”的社会景观,让短视频用户成功地接受并推广国货品牌。网红经济嵌入隐形带货逻辑、数据算法嵌入受众媒介终端、媒介嵌入日常生活消费情景则是短视频嵌入国货消费的方式特征,是短视频发挥产品营销功效的优势所在。 相似文献
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杜传乐 《潍坊教育学院学报》2010,23(1):60-62
由于网络带宽和传输机制的原因,目前教育网站的内容大多以静态的教材为主,而很少有视频、音频等流媒体教学信息。即使有些网站支持视频、音频等流媒体教学内容的在线浏览与下载,但由于网络传输速率很慢,很难实现双向交互,因此效果并不理想。这些在很大程度上削弱了网络教育对众多学习者的吸引力,因此使远程教育的质量和效果大打折扣。组播是一种能够有效地节省网络资源的传输方式。本文的目的是研究基于IP组播技术在远程网络教育中的应用。 相似文献