Mobility-Based Clustering for Scalable and Responsive Routing in Ad-Hoc Networks

在这项研究中，研究人员提出了一种基于移动性的框架，用于无线自组织网络中的自适应分簇和路由。无线自组织网络是一种新兴的网络体系结构，具有高度动态的拓扑结构和有限的资源。在这个框架内，研究人员将解决几个关键的、尚未得到回答的问题，这些问题已经被提出，与自组织网络中的路由问题有关。具体地说，有人认为，为了实现可接受的路由性能，多个路由策略可能需要在同一网络中协同工作。然而，这提出了一个问题，即这些战略应该是什么，以及如何有效地在它们之间切换。此外，已经提出可以使用移动性信息来选择较长寿命的路线，并提高路线创建和维护的效率。然而，还没有提出基于移动性的良好定义的度量来反映路径稳定性的定量度量。在这项研究中，研究人员探索了解决上述每个缺点的新颖而有意义的想法，并将它们构建成一个统一的路由框架。具体地说，研究人员建议开发一种定义明确的基于移动性的路由度量，称为路径可用性。该度量用于自组织网络中的自适应簇表征和路由。基于移动性的簇特征为高效的分布式簇算法提供了基础，该算法自适应地维护簇的组织--每个簇的大小和成员资格由本地节点的移动性特征动态确定。使用此度量，研究人员建议研究主动的簇内和簇间路由策略：簇内路由将基于表驱动的路由协议，该协议维护关于所有簇目的地的最新路由信息，而簇间路由通过在源和目的地之间以动态分层方式构建作为相对稳定的簇的序列的动态分层方式来按需管理。通过主动维护每个簇中的路由，可以实现更高效的路由搜索，并且仅当源或目的地离开其原始簇时，或者如果沿路由的下一个簇变得不可达时，才需要反应性路由修复。对节点移动性的大部分反应是在簇内局部处理的，因此，拓扑变化的深远影响被最小化。通过使集群组织的特点适应本地化的节点移动模式，该战略有望在广泛的条件下表现良好。此外，该框架可以扩展以满足支持多媒体通信的服务质量要求的需要。很少有集群策略定义了自适应集群技术，或者在集群决策过程中考虑了移动性信息。因此，这项工作是对该领域的重大和可持续的贡献。

In this study, the researchers propose to develop a mobility-based framework for adaptive clustering and routing in wireless ad-hoc networks-an emerging class of network architecture that is characterized by its highly dynamic topology and its limited resources. Within this framework, the researchers will address several key, as yet unanswered questions, which have been raised with respect to the routing problem in ad-hoc networks. Specifically, it has been argued that to achieve acceptable routing performance, multiple routing strategies may need to act cooperatively in the same network. However, this raises the question as to what those strategies should be, and how to effectively toggle between them. Furthermore, it has been proposed that mobility information can be used to select longer-lived routes, and to improve the efficiency of route creation and maintenance. However, no well-defined mobility based metric has been proposed that reflects a quantitative measure of path stability. In this study, the researchers explore novel and significant ideas which address each of the shortcomings described above, and builds them into a unifiedrouting framework. Specifically, the researchers propose to develop a well-defined mobility based routing metric, referred to as path availability. This metric is used for adaptive cluster characterization and routing in ad-hoc networks. The mobility-based cluster characterization provides the basis for an efficient distributed clustering algorithm which adaptively maintains a cluster organization-the size and membership in each cluster is determined dynamically by the mobility characteristics of the local nodes. Using this metric, the researchers propose to investigate pro-active intra-cluster and inter-cluster routing strategies: intra-cluster routing will be based on table-driven routing protocols that maintain up-to-date routing information regarding all cluster destinations, whereas inter-cluster routing is managed on a demand-basis by constructing routes in a dynamic hierarchical fashion as a sequence of relatively stable clusters between the source and the destination. More efficient route search is enabled by the proactive maintenance of routes within each cluster, and reactive route repair is only needed if the source or destination depart their original clusters, or if the next cluster along a route becomes unreachable. Most of the reaction to node mobility is handled locally within the clusters, hence, the far-reaching effects of topological changes are minimized. By adapting the characteristics of the cluster organization to localized node mobility patterns, the strategy is expected to perform well over a wide range of conditions. Furthermore, this framework can be extendedto address the need to support QoS requirements for mutlimedia communications. Very few clustering strategies have defined either an adaptive clustering technique, or have factored mobility information into the clustering decision process. Hence, this work represents a significant, and sustainable contribution to the field.