无线多媒体传感器网络最优化资源分配与传输技术研究

Wireless Multimedia Sensor Network is a special kind of wireless sensor network, which is integrated with sensor technology, multimedia information techniques and wireless communication technology. It can be deployed for some practical applications, including military sensing and tracking, environment and security monitoring. Thus, it has received considerable attention and become a hotspot in research area. We attempt to investigate the hotspots of the research on the lifetime of wireless multimedia sensor networks, network utility maximum, opportunities routing protocol. Addressed the performance optimization of network lifetime and resource allocation for wireless video sensor networks, we construct a power consumption model for video sensors, in which video encoding, data communication and error-control behavior are completely considered. Then, we propose a joint optimization of video coding rate, aggregate power consumption and flow control to maximize the network lifetime and meet video quality requirements. Still we also study the problem of data gathering framework in wireless sensor networks and formulate it as a network utility maximization problem. And an opportunistic routing scheme, based on the optimization problem, can be proposed to contribute a distributed framework for data gathering. Moreover, we study a dynamic coding policy which allows network coding applied across sessions and develops a necessary condition for coding policy by denoting the flow gaining from coding. With the coding policy, intermediate nodes can independently judge whether the coding operation is appropriate and easily decide which packet to transmit among the incoming flows. An opportunistic routing protocol joint with opportunistic network coding is proposed for correlated sources. In order to reduce the total transmission, the expected number of coded transmission is introduced as metric for the routing selection. Moreover, the coding gain is defined for the network nodes to count the coding opportunistic, with which the throughput of the wireless sensor network is further increased. The achievements of this project are expected to be applied in high-efficient wireless multimedia sensor networks. We believe that the intellectual property rights obtained from these new techniques can increase our competence in this research area.

无线多媒体传感器网络是传感器技术、多媒体信息技术和无线通信技术的综合体，尤其在敌对和恶劣的网络环境中，有着巨大的应用价值。本课题拟对无线多媒体传感器网络的生命周期、网络效用和路由协议等网络优化问题进行深入研究。首先，针对网络生存周期问题，本课题将通过研究视频压缩编码、视频接收与发送，以及基于网络传输差错控制的节点功率消耗数学模型，并采用拉格朗日对偶理论和次梯度算法，实现信源速率、链路速率、视频编码功率的联合优化。其次，针对网络效用和路由协议问题，本课题将通过研究基于网络编码的机会路由方式以及基于吞吐量增益的组间网络编码决策机制，并引入拥塞代价指标来衡量无线网络链路质量，从而提高网络的吞吐量和传输可靠性。最后，通过研究联合机会网络编码的机会路由协议，增加网络编码的可能，进一步提高网络吞吐量。预期本项目研究成果可应用于未来无线多媒体传感器网，实现网络整体资源分配的优化和网络传输能力的提高。

项目研究的重点在于无线通信资源分配和终端通信模式选择，目的是为了增加系统的频谱利用率且提高系统的传输效率。然而由于多终端通信系统的过程中会对不同用户造成相互之间的干扰。所以如何降低系统总干扰值是本项目的重点之一。除此之外，提高点到点的传输速度，优化系统吞吐量十分重要，本项目研究了基于系统总干扰值最小和系统总吞吐量最优这两个不同的资源分配策略。.针对于多用户共享信道的分配问题，研究了以系统总干扰值最小化和以吞吐量最优化为目标的两种不同分配方案，并从独立资源分配和联合资源分配这两个不同分配策略分别对这两个分配方案进行研究。在仿真验证部分首先使用Matlab仿真软件建立相关的无线通信系统仿真的初始化模型，并对不同场景下多用户接入干扰性能的影响做出了一定的研究和分析。仿真结果表明，在使用优化算法对系统进行多用户终端通信的准入控制和资源分配能有效提高多用户接入的对数和系统的通信性能。且联合分配的资源分配策略的通信性能明显优于独立分配策略。这对未来的实际应用场景有一定的指向性。