无线网状网络环境下的合作缓存关键技术研究

项目名称： 无线网状网络环境下的合作缓存关键技术研究

项目编号： No.60803137

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 吴维刚

作者单位： 中山大学

项目金额： 20万元

中文摘要： 无线网状网（WMN）将成为下一代无线接入网的主流技术。本项目着重研究了WMN 环境下合作式数据缓存管理相关的关键技术。数据缓存是一种非常适于无线环境的数据管理技术，可以有效地减少数据访问开销，提高数据维护效率。合作式缓存通过网络结点相互合作实现缓存共享，从而进一步提高缓存的效用。由于 WMN 在体系结构、通讯模式等方面的独特性，已有的缓存技术不能满足 WMN 环境的要求也不能充分利用 WMN 的特点。我们的研究涵盖了合作式数据缓存的放置、发现以及一致性维护三大问题。其基本思路是，基于WMN的网络结构、通信方式、节点移动性等几个方面的特性，有针对性地研究设计了适宜的机制和算法，主要包括基于层次结构的缓存体系结构、层次性缓存放置判据和放置算法设计、基于无线链路开放性的缓存放置和发现机制、基于Voronoi图的缓存发现机制、基于节点合作的缓存一致性维护方法等。基于我们的研究成果，我们搭建了一个真实部署的实验演示系统，并以Web访问具体为应用，开发实现了合作式缓存的实验性系统。项目的成果已经发表在了主流的国际会议和期刊上，为国际同行引用，对相关领域的研究和应用起到了积极的推动作用。

中文关键词： 合作式缓存；无线网状网；移动计算；数据管理

英文摘要： WMN is perceived to be the major technology for Internet access in the future. This project focuses on the cooperative caching system in WMNs. Caching has been widely used in various environments. In wireless networks, cooperative caching, i.e. sharing cache copies among network nodes, is a promising technique for further reduce data access cost. Although there have been quite a number of studies on cooperative cahing in wireless networks, the features of WMN have not been considered. In this project, we systematically study cooperative caching system with respect to the chacracteristics of WMN, including network architecture, communicaiton path, node mobility, etc. Our work covers all the three major problems in cooperative cahing, i.e. cache placement, cache discovery and cache consistency. More precisely, we propose the design of hierachrical cooperative caching system, include: 1) A hierarchical cache system architecture to fit the layered network of WMN. The mesh routers act as local cache coordinator to manage the cache copies in a cell. 2) A hierarchical cache placement algorithm, with network level metric and cell level metric. 3) A overhearing-aided cache placement algorithm, which makes use of the openess of wireless links to obtain more cache information and consequently increase utility of cache copies. 4) Voronoi digram based cache discovery algorithms, which make use of the concept of Voronoi diagram to maintain cahce ifnormation so as to reduce the cost of maintenance. 5) A cooperative cachi cosistency approach with too cooerative techniques to reduce the cost of cache validation report delivery. With our proposed algorithms and mechanisms, we establish a preliminary testbed, which has four customized wireless mesh routers. Notebooks are used as the mobile clients. Web service is assumed to be the upper layer application. Our research results have been published in vaious major conferences and journals, which inidcates that our work is recognized by scholars in the related fields.

英文关键词： Cooperative Caching; WMN; Mobile Computing; Data Management