传统流媒体资源交互方法采用传统的网络站点方式,采用单台计算机实现资源的访问与存储,由于系统网络速度的瓶颈因素,导致系统整体访问效率低下。为此提出一种基于分级结构的大压缩率流媒体资源高速访问技术,采用分段思想将同一时间对同一资源的访问群体分割问多个不同的段,然后根据站点的相似性,将访问特性相同的站点进行归类,在此基础上,对流媒体资源的大数据量进行有效的压缩控制,降低系统通讯载荷,从而实现高效的资源访问。采用100个随机分布的访问站点进行流媒体资源的访问测试实验,结果显示,采用分级结构和压缩算法后,系统的访问效率大大提高,能够满足下一代流媒体资源大数据量的访问需求,具有很好的工程应用价值。

Traditionally, the streaming media resource was carried out at one single computer, the speed of network was limited. The high speed access of streaming based on hierarchical structure and large compression rate technology was proposed, segmented thinking was used to split the resource to several different segments, and then the similarity one of the site were collected together by the classified characteristics, on this basis, streaming media resource with large amount of data was compressed for effective control and reducing the system communication load. 100 randomly dis-tributed streaming media resource was used to test the ability of site access, the result shows that, with the hierarchical structure and compression algorithms, the system efficiency is greatly improved and it can meet the large amounts of data access for the next generation, and it has good value for engineering application.

对于新一代的无线网络,宽带无线系统的融合将成为一个重要的技术难题。近年来,尽管一些研究人员已经提出了几种技术方案用来增强第二代媒体访问控制协议(MAC),但这些设计主要针对的是数字信息。针对实时宽带信源给出一个了更好的集中控制访问技术,这项技术通过实现信息源的统计复用,并根据不同用户的服务质量需求来对无线终端进行组合,使之形成一个固定的有线宽带网络。同时这项技术将轮询方式与随机接入方式整合在一起,基站中的数据包调度程序负责动态地选择最高传输需求吞吐量的接入方式。对上述方法进行了性能测定,并估算了相关的参数。

For the new generation of wireless networks,the convergence of wireless systems with broadband services is becoming an important technical issue.In recent years,several schemes for enhancing second-generation media access control(MAC)protocols have been proposed,which,however,mainly focus on digital information.In this paper,an enhanced centrally controlled access technique for real-time broadband sources is presented.It enables full integration of wireless terminals into fixed wired broadband networks by realizing the statistical multiplexing of sources and depending on the user''s requirements of quality-of-service. Furthermore,the technique combines random access with polling,and the packet scheduler running at the base station dynamically selects the access method with the highest throughput for transmission of capacity requests. The performance of the method is tested,and the relevant parameters are calculated.

根据中国电力工业通信规范对配电网通信数据的要求,研究了一种在IEEE 802.15.4标准媒体访问控制(MAC)层协议中引入服务质量(QoS)支持的信道访问机制QoS-MAC模型。通过将配电网遥信、遥控、遥测三类通信数据分为3种优先等级的传输数据,建立节点内三级数据缓冲队列状态的马尔可夫链模型。依据该模型建立了每个节点的信道访问冲突模型、不同优先级数据网络有效吞吐率模型、传输延时模型、节点的无线信道冲撞率模型。通过仿真实验研究,衡量配电网无线传感器网络数据通信的性能。在不同的配电网数据产生率的情况下仿真实验结果表明,所提出的方法可为基于无线传感器网络的配电网数据通信提供有效的QoS保障。

According to the requirements of power industry specifications on communication data of the distribution power grid (DPG),an enhanced quality of service (QoS)-media access control (MAC) model with channel access mechanism based on IEEE 802.15.4 protocol is researched.By dividing the three communication data of telesignalisation,telecontrol and telemetering in DPG into three priority levels of transmit data,a Markovian chain model of node buffers is built.According to the model,every node”s channel access conflict model,different priority levels of network data throughput models,the communication time-delay model and wireless channel collision model are developed.A simulation analysis is designed to analyze the wireless sensor networks(WSNs)data communication performance of the DPG.The simulation results in different distribution data rate scenarios show that the method proposed is able to provide effective QoS for DPG data communication based on WSNs.

为了深入探讨车载网络协议IEEE 802.11p的特性,首先对该协议的物理层、媒体控制访问层及其帧结构进行了详细介绍,然后从工作频率、传输速率及最大功耗等方面与其他短距离无线通信技术进行对比分析,最后归纳出车载网络协议IEEE 802.11p作为一项新的协议标准,在车载网络的实际应用中有着区别于其他无线通信技术的特有优势。因此,对该协议的突破性研究,将有助于车载网络技术在智能交通系统领域走向实用,既具有一定的理论意义,又具有重要的应用前景。

In order to further investigate the characteristics of IEEE 802.11p protocol for vehicular networks,first of all,the physical layer,media access control layer and its frame structure are described in detail,and then the working frequency,trans-mission rate and maximum power consumption of the protocol are compared with those of other short distance wireless communi-cation technologies. Finally,as a new protocol standard,IEEE 802.11p protocol for vehicular networks has a unique advantage from other wireless communication technologies. Therefore,the breakthrough research of the protocol will help vehicular network technologies to move towards practical application for sure in the field of intelligent transportation system,and has the theoreti-cal significance and application prospect.

研究并提出了一种基于二维访问机制的数据缓存结构（2D Cache）及其更新管理策略．该缓存结构可以在控制硬件存储开销的同时，有效提升可重构系统的数据访存效率．实验结果表明，仅需4 KB的数据缓存开销，可重构系统的访存性能提升了29.16％～35.65％，并且对于不同标准的媒体处理算法都能获得较好的优化效果，具有很好的适应性．芯片实测结果表明，采用所述数据缓存设计方案的可重构系统可以在200 MHz下满足1080p＠30fps的实时解码需求，与国际同类架构相比，性能提高了1.8倍以上．

In order to improve the data flow of the reconfigurable system with a lower embedded data memory cost,a data cache optimization method is proposed,including the two-dimensional Cache structure and the related cache management strategy.The experimental results show that the approach is efficient for various multimedia applications,and the memory access performance of the reconfigu-rable system can be improved by 29.16% to 35.65% with a 4 KB data cache.The proposed data cache structure was adopted in a reconfigurable system and realized with real chip.Based on the the proposed data cache structures,the reconfigurable system can support the 1080p@30fps stream deco-ding at the clock frequency of 200 MHz.Moreover,the performance of the reconfigurable system is 1 .8 times higher than that of other reconfigurable architectures.