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

在这项研究中，研究人员建议开发一种基于移动性的框架，用于无线自组织网络中的自适应集群和路由。无线自组织网络是一种新兴的网络架构，其特点是其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，尚未回答的问题，这些问题已经提出了关于ad-hoc网络中的路由问题。具体来说，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，这就提出了一个问题，即这些策略应该是什么，以及如何有效地在它们之间切换。此外，还提出了机动信息可以用于选择更长的路径，并提高路径创建和维护的效率。然而，没有明确定义的基于移动度的度量被提出来反映路径稳定性的定量度量。在这项研究中，研究人员探索了新颖而重要的想法，这些想法解决了上述每一个缺点，并将它们构建成一个统一的研究框架。具体来说，研究人员建议开发一种定义良好的基于移动性的路由度量，称为路径可用性。该度量用于自适应簇表征和ad-hoc网络中的路由。基于移动性的聚类特征为高效的分布式聚类算法提供了基础，该算法可自适应地维持集群组织，每个集群的大小和成员资格由局部节点的移动性特征动态决定。利用这一度量，研究人员建议研究主动的集群内和集群间路由策略：集群内路由将基于表驱动的路由协议，该协议维护有关所有集群目的地的最新路由信息，而集群间路由是基于需求管理的，通过在源和目的地之间以动态分层方式构建路由，作为相对稳定的集群序列。通过主动维护每个集群内的路由，可以实现更有效的路由搜索，只有当源或目的地离开其原始集群，或者路由沿线的下一个集群不可达时，才需要进行被动路由修复。大多数对节点移动的反应在集群内部局部处理，因此，拓扑变化的深远影响被最小化。通过使集群组织的特征适应局部节点移动模式，该策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QoS需求。很少有聚类策略定义了自适应聚类技术，或者在聚类决策过程中考虑了移动性信息。因此，这项工作对该领域作出了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.