Fault Tolerance Analysis of Mobile Systems

随着数字蜂窝系统的进步，无线移动网络的部署正在迅速增加，这有望在移动环境中实现大规模、可靠的语音、数据和多媒体通信。个人通信服务（PCS）的实现将增加公共和私营部门对移动网络的依赖，这意味着导致通信或关键数据丢失的系统故障将是不可容忍的。容错分析提供了对故障后系统功能的理解。有线网络的容错分析，如可靠性、可用性和生存性问题，一直得到很好的研究。用户的移动性以及运动的不可预测性表明，有线网络的模型和假设不能转移到无线、移动领域。目前对移动网络容错分析的关注还很少。本课题通过对提供大规模pc机（包括语音、数据和多媒体通信）的系统容错分析的探索性研究填补了这一空白。这些系统由与现有（有线）基础设施互连的移动蜂窝或微蜂窝网络中的射频通信组成。由于所提供的服务和底层互连网络的异质性，以及由于无线通信介质固有的不可靠性，这些系统的容错标准和评估方法并不是立即显而易见的。这个项目的目标是制定适当的研究问题关于移动系统的容错，并指出一个分析策略。这包括识别对测量系统鲁棒性最有用的容错参数（或提出新的容错参数），开发网络建模方法（或一组方法），并使用这些模型提出初步的容错算法。

Deployment of wireless, mobile networks is rapidly increasing as advances in digital cellular systems promise large-scale, reliable voice, data, and multimedia communications in a mobile environment. The realization of Personal Communications Services (PCS) will increase dependence on mobile networks by the mass public and private sectors, implying that system failure resulting in loss of communication or critical data will not be tolerated. Fault tolerance analysis provides an understanding of system functionality in the wake of failures. Fault tolerance analysis such as the reliability, availability, and survivability problems continues to be well researched for wired networks. The mobility of the user along with the unpredictability of motion indicate that models and assumptions for wired networks cannot be carried over to the wireless, mobile domain. Very little focus has yet been placed on fault tolerance analysis for mobile networks in particular. This project fills this void through exploratory research on fault tolerance analysis of systems which provide large-scale PCS, including voice, data and multimedia communications. These systems are comprised of radio frequency communications within mobile cellular or picocellular networks that are interconnected to the existing (wired) infrastructure. The fault tolerance criteria and evaluation approach are not immediately apparent for these systems due to the heterogeneity of the services provided and of the underlying interconnection network, and due to the inherent unreliability of the wireless communications medium. The goal of this project is to formulate the appropriate research problems regarding fault tolerance of mobile systems and to indicate an analysis strategy. This includes identifying fault tolerance parameters (or propose new ones) which are most useful to measuring system robustness, developing a network modeling approach (or set of approaches), and proposing preliminary fault tolerance algor ithms using these models.