Named data networking （NDN） is a new Internet architecture that replaces today＇s focus on where - addresses and hosts with what -- the content that users and applications care about. One of NDN＇s prominent advanta...Named data networking （NDN） is a new Internet architecture that replaces today＇s focus on where - addresses and hosts with what -- the content that users and applications care about. One of NDN＇s prominent advantages is scalable and efficient content distribution due to its native support of caching and multicast in the network. However, at the last hop to wireless users, often the WiFi link, current NDN im- plementation still treats the communication as multiple uni- cast sessions, which will cause duplicate packets and waste of bandwidth when multiple users request for the same popular content. WiFi＇s built-in broadcast mechanism can alleviate this problem, but it suffers from packet loss since there is no MAC-layer acknowledgement as in unicast. In this paper, we develop a new NDN-based cross-layer approach called NLB for efficient and scalable live video streaming over wireless LAN. The core ideas are： using WiFi＇s broadcast channel to deliver content from the access point to the users, a leader- based mechanism to suppress duplicate requests from users, and receiver-driven rate control and loss recovery. The design is implemented and evaluated in a physical testbed comprised of one software AP and 20 Raspberry Pi-based WiFi clients. While NDN with multiple unicast sessions or plain broadcast can support no more than ten concurrent viewers of a 1Mbps streaming video, NDN plus NLB supports all 20 viewers, and can likely support much more when present.展开更多
The Fast Broadcasting scheme is one of the simplest schemes that provide video services. In this scheme, the video is divided into equal-sized segments depending upon the bandwidth allocated by the video server. If th...The Fast Broadcasting scheme is one of the simplest schemes that provide video services. In this scheme, the video is divided into equal-sized segments depending upon the bandwidth allocated by the video server. If the video length is not known, then this scheme cannot be applied as the number of video segments cannot be determined. In a live video wherein the video size is unknown, especially the ending time of the live broadcast, e.g., cricket match, this scheme cannot be applied. In this paper, we propose a model that helps the Fast Broadcasting scheme to support live video broadcasting. The basic architecture of the system consists of a live system with one video channel that broadcasts the live video and a video server that broadcasts the already broadcast live video to users.展开更多
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi...In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.展开更多
With the increasing popularity of solid sate lighting devices, Visible Light Communication (VLC) is globally recognized as an advanced and promising technology to realize short-range, high speed as well as large capac...With the increasing popularity of solid sate lighting devices, Visible Light Communication (VLC) is globally recognized as an advanced and promising technology to realize short-range, high speed as well as large capacity wireless data transmission. In this paper, we propose a prototype of real-time audio and video broadcast system using inexpensive commercially available light emitting diode (LED) lamps. Experimental results show that real-time high quality audio and video with the maximum distance of 3 m can be achieved through proper layout of LED sources and improvement of concentration effects. Lighting model within room environment is designed and simulated which indicates close relationship between layout of light sources and distribution of illuminance.展开更多
The integration of reliable Video-on-Demand (VoD) broadcasting schemes in the DVB-h transmission system is studied, exemplary for Pyramid Broadcasting (PB). Sophisticated VoD broadcasting schemes such as PB allow rece...The integration of reliable Video-on-Demand (VoD) broadcasting schemes in the DVB-h transmission system is studied, exemplary for Pyramid Broadcasting (PB). Sophisticated VoD broadcasting schemes such as PB allow receivers to tune into the ongoing transmission of a video-stream at arbitrary time, while still being able to receive the multimedia sequence from the beginning to end, after a short initial playout latency. Raptor coding, integrated in the FLUTE protocol, is combined with the traditional PB scheme in order to provide high service and presentation reliability. We give a short overview on the DVB-h transmission system as well as on the FLUTE protocol. We present and discuss options for the integration of VoD broadcasting schemes in combination with Raptor coding. We achieve backward-compatibility even with terminals not supporting Raptor coding. Simulation results show the benefits of the discussed VoD scheme compared to existing carousel approaches in DVB-h.展开更多
科学技术不断创新的背景下,第五代移动通信技术(5th Generation Mobile Communication Technology,5G)、人工智能(Artificial Intelligence,AI)技术、云编辑技术及区块链技术等诸多新技术应运而生,并广泛应用于传媒领域。借助新技术可...科学技术不断创新的背景下,第五代移动通信技术(5th Generation Mobile Communication Technology,5G)、人工智能(Artificial Intelligence,AI)技术、云编辑技术及区块链技术等诸多新技术应运而生,并广泛应用于传媒领域。借助新技术可显著提升短视频新闻节目制播效率及内容质量,带给观众更好的观看体验,增强观众黏性,提高短视频新闻节目的收视率,推动短视频新闻媒体实现可持续发展。为保证新技术的有效应用,探讨新技术支持下的短视频新闻节目制播策略。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
文摘Named data networking （NDN） is a new Internet architecture that replaces today＇s focus on where - addresses and hosts with what -- the content that users and applications care about. One of NDN＇s prominent advantages is scalable and efficient content distribution due to its native support of caching and multicast in the network. However, at the last hop to wireless users, often the WiFi link, current NDN im- plementation still treats the communication as multiple uni- cast sessions, which will cause duplicate packets and waste of bandwidth when multiple users request for the same popular content. WiFi＇s built-in broadcast mechanism can alleviate this problem, but it suffers from packet loss since there is no MAC-layer acknowledgement as in unicast. In this paper, we develop a new NDN-based cross-layer approach called NLB for efficient and scalable live video streaming over wireless LAN. The core ideas are： using WiFi＇s broadcast channel to deliver content from the access point to the users, a leader- based mechanism to suppress duplicate requests from users, and receiver-driven rate control and loss recovery. The design is implemented and evaluated in a physical testbed comprised of one software AP and 20 Raspberry Pi-based WiFi clients. While NDN with multiple unicast sessions or plain broadcast can support no more than ten concurrent viewers of a 1Mbps streaming video, NDN plus NLB supports all 20 viewers, and can likely support much more when present.
文摘The Fast Broadcasting scheme is one of the simplest schemes that provide video services. In this scheme, the video is divided into equal-sized segments depending upon the bandwidth allocated by the video server. If the video length is not known, then this scheme cannot be applied as the number of video segments cannot be determined. In a live video wherein the video size is unknown, especially the ending time of the live broadcast, e.g., cricket match, this scheme cannot be applied. In this paper, we propose a model that helps the Fast Broadcasting scheme to support live video broadcasting. The basic architecture of the system consists of a live system with one video channel that broadcasts the live video and a video server that broadcasts the already broadcast live video to users.
基金Support to the SatNEx-Ⅲ Network of Experts (SatNEx-Ⅲ) CoO2,2011-2012
文摘In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.
文摘With the increasing popularity of solid sate lighting devices, Visible Light Communication (VLC) is globally recognized as an advanced and promising technology to realize short-range, high speed as well as large capacity wireless data transmission. In this paper, we propose a prototype of real-time audio and video broadcast system using inexpensive commercially available light emitting diode (LED) lamps. Experimental results show that real-time high quality audio and video with the maximum distance of 3 m can be achieved through proper layout of LED sources and improvement of concentration effects. Lighting model within room environment is designed and simulated which indicates close relationship between layout of light sources and distribution of illuminance.
文摘The integration of reliable Video-on-Demand (VoD) broadcasting schemes in the DVB-h transmission system is studied, exemplary for Pyramid Broadcasting (PB). Sophisticated VoD broadcasting schemes such as PB allow receivers to tune into the ongoing transmission of a video-stream at arbitrary time, while still being able to receive the multimedia sequence from the beginning to end, after a short initial playout latency. Raptor coding, integrated in the FLUTE protocol, is combined with the traditional PB scheme in order to provide high service and presentation reliability. We give a short overview on the DVB-h transmission system as well as on the FLUTE protocol. We present and discuss options for the integration of VoD broadcasting schemes in combination with Raptor coding. We achieve backward-compatibility even with terminals not supporting Raptor coding. Simulation results show the benefits of the discussed VoD scheme compared to existing carousel approaches in DVB-h.
文摘科学技术不断创新的背景下,第五代移动通信技术(5th Generation Mobile Communication Technology,5G)、人工智能(Artificial Intelligence,AI)技术、云编辑技术及区块链技术等诸多新技术应运而生,并广泛应用于传媒领域。借助新技术可显著提升短视频新闻节目制播效率及内容质量,带给观众更好的观看体验,增强观众黏性,提高短视频新闻节目的收视率,推动短视频新闻媒体实现可持续发展。为保证新技术的有效应用,探讨新技术支持下的短视频新闻节目制播策略。
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。
