ISSN 1000-1239 CN 11-1777/TP

计算机研究与发展 ›› 2018, Vol. 55 ›› Issue (2): 338-345.doi: 10.7544/issn1000-1239.2018.20160929

• 综述 • 上一篇    下一篇

移动机会网络中接触时间感知的协作缓存策略

郑啸, 高汉, 王修君, 秦锋   

  1. (安徽工业大学计算机科学与技术学院 安徽马鞍山 243002) (xzheng@ahut.edu.cn)
  • 出版日期: 2018-02-01
  • 基金资助: 
    国家自然科学基金项目(61402008,61402009);安徽省高校自然科学研究重大项目(KJ2014ZD05);安徽省科技重大专项(16030901060);安徽省高校优秀青年人才支持计划

Contact Duration Aware Cooperative Data Caching in Mobile Opportunistic Networks

Zheng Xiao, Gao Han, Wang Xiujun, Qin Feng   

  1. (School of Computer Science and Technology, Anhui University of Technology, Maanshan, Anhui 243002)
  • Online: 2018-02-01

摘要: 数据访问效率一直都是移动机会网络研究中的一个备受关注的问题.协作缓存技术经常被用来提高网络数据访问效率,但是该类网络中节点的强自主移动性和有限的接触时间使得传统的缓存技术无法得到有效应用.首先提出一个新的度量节点在协作缓存中重要程度的指标,即节点重要度.基于此指标,利用贪心算法选择初始缓存节点;利用缓存节点相遇的机会,进行缓存数据的主动再分配.为了适应节点间有限的接触时间,提出了数据分片策略,并使用随机线性网络编码方法对分片进行编码,以解决数据恢复时的赠券收集问题.此外为每个节点确定了缓存边界来限制缓存数据量,从而合理利用缓存空间.最后,通过实验验证了提出的缓存协议能够有效地提高数据访问效率.

关键词: 移动机会网络, 数据访问, 协作缓存, 接触持续时间, 随机线性网络编码

Abstract: How to improve the efficiency of data access is always a hot topic in the research area of mobile opportunistic networks. Traditional cooperative caching techniques are commonly used to improve the performance of data access. However, the strongly independent mobility and limited contact duration of the mobile nodes render these traditional caching schemes inefficient. Firstly, a new metric, called as node important degree, is proposed to determine which node is more important to cooperative data caching. Based on this metric, a greedy algorithm is used to select initial cache nodes, and subsequently the cache data will be redistributed among these cache nodes actively as they meet each other. A novel data fragmenting strategy is suggested to adapt to the limited contact duration between nodes with the aim to make our protocol suitable for short-duration contact between cache nodes. In order to solve the coupon collector’s problem in data recovery, a randomly linear network coding method is used to encode the data fragmentations. Moreover, we describe an adaptive caching bound calculation method for each mobile node to limit the amount of data it caches, which is helpful to the rational utilization of cache space. Experimental results show that our suggested cooperative caching protocol can significantly improve the efficiency of data access in mobile opportunistic networks.

Key words: mobile opportunistic networks, data access, cooperative caching, contact duration, random linear network coding

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