基于MBMS的手机电视技术

多媒体广播组播业务(MBMS)是3GPP Release 6版本中引入的一项重大功能,目的在于节省系统资源,为用户提供广播或者组播的分组数据业务.作为一种具体的MBMS应用,手机电视技术在3G业务中占有重要的地位.文中介绍了多媒体广播和组播技术(MBMS),包括MBMS的网络结构、业务流程以及基于TD-SCDMA的MBMS系统架构,对LTE中的E-MBMS技术进行了初步研究,并从逻辑结构、业务模式和信道结构等方面简单分析了从MBMS到E-MBMS的演进.     

从MBMS向E-MBMS的演进

经过长期的研究和发展,多媒体广播/组播业务(MBMS)在R6、R7版本的3G系统中已经取得了完整的实现,但是仍然无法满足日益增长的业务需求,尤其是用户和运营商对手机电视业务的强烈需求。随着R8规范的开始制定,一方面为了进一步提高MBMS的业务性能,另一方面需要适应新的系统架构演进/长期演进(SAE/LTE)系统,MBMS在逻辑架构、业务模式、传输方式和信道结构等方面进行了重大改进。通过分析研究,文章就这几个方面详细地阐述了从现有的MBMS(即R6/R7 MBMS)到演进多媒体广播/组播业务(E-MBMS)(包括SAE MBMS和LTE MBMS)的演进过程。     

基于LTE的E-MBMS传输技术的研究

本文简单介绍了E-MBMS的体系架构和传输方式,重点研究了多小区传输方式MBSFN,包括传输区域、传输信道、参考信号设计等,并对MBSFN系统初步提出了一种结合MIMO传输技术的传输方案,目的是为了实现MBSFN系统的性能优化,提高小区边缘用户的接收性能。     

中兴HSPA+MBMS特色方案引手机电视热潮

MBMS网络结构MBMS(Multimedia Broadcast/Multicast Service)即多媒体广播/组播业务,是一种共享网络资源,是从一个数据源向多个目标传送数据的技术,是3GPP R6定义的多媒体广播组播功能。MBMS提供点到多点单向多媒体服务的技术,实现网络资源共享,提高网络资源的利用率,尤其是宝贵的空中接口资源。为了实现MBMS,需要对WCDMA网络中现有的SGSN(Serving GPRS Support Node)、GGSN(Gateway GPRS SupportNode)、RNC(Radio Network Con-troller)和U(E User Equipment)等节点增加MBMS功能,同时需要增加广播和多播服务中心(…     

一种IMS与MBMS融合的方案设计

介绍了多媒体广播组播服务(MBMS)和IP多媒体系统(IMS)的融合方案,分析了该方案的系统架构设计和关键步骤的信令流程.最后,在该方案基础上提出了应用实例,并对该方案的应用前景进行了展望.     

TD-SCDMA系统中多媒体广播业务的实现

多媒体业务是目前被业界看好的一个非常有潜力的应用。多媒体广播的一种主要技术种类是基于移动通信系统蜂窝网的多媒体广播和组播技术（MBMS）标准。主要介绍了在TD-SCDMA移动通信系统中如何实现多媒体广播业务,并介绍了相关技术的标准进展、网络架构以及具体的技术方案。     

中兴通讯WCDMA MBMS解决方案

1前言 多媒体广播/组播业务是一种共享网络资源从一个数据源向多个目标传送数据的技术.在传统WCDMA网络中,小区广播业务(CBS)允许低比特率数据通过小区共享公共信道向所有用户发送,属于消息类业务,在R99中只有小区广播短消息业务(SMS)使用CBS.为了在提供多媒体业务的同时有效地利用移动网络资源,3GPP在R6中提出了多媒体广播/组播业务(MBMS).MBMS在移动网络中提供一个数据源向多个用户发送数据的点到多点业务,实现网络资源共享,使资源的利用取决于内容渠道的数量,而非用户数量,从而提高网络资源,尤其是宝贵的空中接口资源的利用率.MBMS不仅能实现纯文本、低速率的消息类组播和广播,还能实现高速多媒体业务的组播和广播,提供丰富的视频、音频和数据业务,这无疑顺应了未来移动通信的发展趋势,为3G的发展提供更好的前景.     

基于BCMCS的精密定位信息移动广播方案设计

主要研究在CDMA2000 1xEV-DO网络中建立基于BCMCS的移动广播网络方案,具体内容包括了BCMCS的介绍,广播方案的网络拓扑、基本流程图和关键技术等。方案将应用于定位信息分发业务当中,实现将从大众导航与位置服务信息处理服务中心获得的精密定位信息实时送达到用户移动终端上,解决定位信息分发业务无法实现大规模用户和快速实时送达的不足,实现更高效的传输。     

广播/组播业务的发展及在B3G中的应用

随着多媒体业务的快速发展,通过点对点移动流媒体技术提供的业务量远远不能满足未来的需求,所以提出广播/组播技术来进一步提高未来多媒体业务量.本文主要介绍广播/组播的概念、在3G/B3G标准化中进展情况以及国内研究进展情况.     

CMMB中央业务分发与地方业务集成方案探讨

对目前移动多媒体广播中央业务分发和地方业务集成实施方案进行了详细介绍,并对其改进方案进行了研究和实验室测试,最后提出了一种具有前瞻性的设想方案.     

Real-Time Streaming Relay Mechanism for P2P Conferences on Hierarchical Overlay Networks

A peer-to-peer (P2P) multimedia conferencing service is operating that users share their resources to each other on the Internet. It can solve the problem in the centralized conferencing architecture, such as the centralized loading, single point error, and expensive infrastructure. However, P2P networks have the problem that a peer has a difference between the physical location and logical location in the overlay network. In the viewpoint of P2P networks, the nearest conference resource may be far away geographically. The P2P-session initiation protocol (P2P-SIP) multimedia conference is to construct an application-based logical multicast network efficiently according to physical network information. Thus, this paper proposes a real-time streaming relay mechanism for P2P conferences on hierarchical overlay networks. The real-time streaming relay mechanism can improve the transportation efficiency of conferencing stream exchange well based on the application-layer multicast (ALM) structure and the hierarchical overlay networks.     

A novel adaptive modulation and coding strategy based on partial feedback for enhanced MBMS network

The difference in link condition of broadcast/ multicast users and the limitation of uplink resource, make it difficult to utilize adaptive modulation and coding （AMC） in the enhanced multimedia broadcast and multicast service （E-MBMS） network. To obtain the improvement of system throughput, this study proposes an adaptive modulation and coding scheme based on partial feedback, by which only partial users whose channel qualities are lower than the system threshold need to make a response to the modulation coding scheme （MCS） adaptation procedure. By this investigation, an adaptive scheme can be introduced in the E-MBMS network. Both the theoretical analysis and simulation results demonstrate the efficiency of the proposed strategy, in which the performance is close to the ideal one and has a significant throughput improvement when compared with that of the fixed MCS transmission scheme.     

P2P网络架构的资源搜寻算法设计

结构化对等(P2P,Peer to Peer)架构的资源搜寻算法如Chord、CAN、Pastry等的提出,改变了非结构化P2P架构的泛洪式资源搜寻的方式,降低了P2P资源搜寻信息的流量,从而增强了系统的扩展性.但是以上算法均未考虑到节点间实际物理距离对搜寻路径长度的影响.文章提出一种基于节点能力和节点区域性的结构化搜寻算法,该算法综合了CBT和Grapes的优点并充分考虑到节点的区域性以及节点能力,从而构建了一个短搜寻路径能力集包容的P2P系统.     

An Adaptive Power Control Scheme for Multicast Service in Green Cellular Railway Communication Network

Along with emerging increasing multimedia service need from the big amount of users in the train, wireless cellular railway network has big energy saving potential with its own specific characteristics, which is widely deployed over the world. Enhanced Multimedia Broadcast Multicast Service (E-MBMS) is a prevalent solution for high speed data handling. In this paper, to achieve an energy efficient solution for wireless cellular railway network, we proposed an optimal power control solution to adjust eNodeB’s transmission power adaptively based on actual Signal to Interference plus Noise Ratio (SINR) for Multimedia Broadcast multicast service Single Frequency Network (MBSFN) at User Equipment (UE) side when provide E-MBMS. We established the system model and proposed the optimization algorithms to calculate the E-MBMS transmit power. We also designed the geometry group scheme to significantly reduce the calculation effort. And proposed the Mobility offset parameter to cope with high speed mobility of the train and variation of signal level. Finally, Simulation results showed that this solution can be a good way for high network energy efficiency and can dynamically adjust the output power for the multicast service in the wireless cellular railway communication network.     

基于区域资源聚集的P2P网络

P2P网络规模的扩大使基于洪泛的检索方法产生严重的通信消耗问题,提出一种区域资源聚集模型,对非结构化对等网络中分散的资源进行分层聚集,形成大粒度的资源实体,从而显著缩减网络规模,并综合考虑影响资源检索命中率的多种因素,构造资源引用价值衰减函数来调节描述资源实体的引用价值向量和矩阵.检索时从区域资源簇中具有最大引用价值的资源组开始逐步寻找所要的资源.实验证明,该方法的消息转发范围得到控制、检索命中率有显著提高.     

SKIP:an efficient search mechanism in unstructured P2P networks

Search efficiency and accuracy of resource are important considerations for search algorithm in peer-to-peer(P2P)network.Most search algorithms use flooding among neighbor nodes to search relevant resource.However,this usually causes great amount of redundant messages,which results in high search costs and low search precision.In this paper,we use vector space model(VSM)and relevance ranking algorithms to construct overlay network,and a novel search mechanism search with K-iteration preference(SKIP)based on semantic group for P2P networks is proposed to efficiently solve these problems.The key idea of SKIP is to reorder the semantic neighbors of nodes according to relevant scores and to utilize preference selection during the process of query.We analysis and implement the scheme and reveal that the SKIP provides a low overhead on topology maintenance,which can be effectively used in P2P searching and verify it outperformanee in higher precision and lower search cost by comparing with current semantic-based searching mechanism gnutella-like efficient searching system(GES).     

P2P网络中一种新型的基于DHT的多关键字信息检索模型

在现有的P2P系统应用中,信息的检索是一项非常重要的内容,但现有的检索机制不够高效.本文针对这个问题,在现有的结构化DHT模型基础上,提出一种新型的多关键字检索模型.在一个P2P节点上存储包含一个资源内容的多个关键字的信息,使用带有权重的多关键字向量代表资源信息,并把请求也表示成带有权重的多关键字向蝌量,对请求和资源信息的向量进行匹配,选取符合要求的信息.仿真和分析表明此方案可以显著改善搜索结果的精确性和大大减少搜索所需的寻路跳数.     

A game theoretic approach to video streaming over peer-to-peer networks

We consider the problem of foresighted multimedia resource reciprocation in peer-to-peer (P2P) networks, which consist of rational peers aiming at maximizing their individual utilities. We introduce an artificial currency (credit) to take into account the characteristics of different parts of the video signal. The resource reciprocation with the proposed credit metric can be formulated as a stochastic game, in which the peers determine their optimal strategies using Markov Decision Process (MDP) framework. The introduced framework can be applied to the general video coding, and in particular, is suitable for the scalable video where various parts of the encoded bit stream have significantly different importance for the video quality.     

Potentials and challenges of peer-to-peer based content distribution

Multimedia content currently accounts for over three quarters of all Internet traffic. This increase in traffic volume and content availability derives from a paradigm shift from the traditional text and picture based Web, to more resource demanding audio and video content. A controversial driver for this development is content distribution systems based on peer-to-peer overlay networks. Flooding the Internet with often illegal content, these networks now pose challenges to all actors in the value chain. However, if viewed as surmountable challenges in an evolutionary path, peer-to-peer technology has the potential of increasing efficiency in content distribution and unleashing resources to form scalable and resilient overlay networks of unprecedented dimensions.

In this paper we examine the potentials and challenges of peer-to-peer technology in content distribution, and analyse how, and under which circumstances, peer-to-peer technology can be used to increase the efficiency of multimedia services. The paper provides an up-to-date overview of the development of peer-to-peer networks as well as describing the economics laws governing their use. To conclude the study, the paper analyses Skype, a well known telecommunications service utilising the peer-to-peer technology, as well as demonstrating the benefits of peer-to-peer based content distribution using empirical data from the Danish Broadcasting Corporation.     

一种基于P2P技术的网络管理系统的设计

文章首先分析了传统对等(Peer-to-Peer,P2P)网络模型存在的优缺点,并在此基础上提出一种改进的P2P网络模型,如丢弃已见过的消息、原路返回应答消息和设置广播的半径等.同时,对网络模型中的节点管理功能模块、资源搜索功能模块和下载管理功能模块等做了较详细的介绍;文章作者在此基础上,设计、开发了一种基于P2P的网络管理系统(NMS).