CAREER: Resource Management in Mobile ad hoc Networks - the Spatial Dimension

建议的研究的目标是发展一个全面的理解空间方面的分布式计算在移动的系统。传统上，分布式计算中的事件按时间排序。标量和矢量时钟用于表示逻辑时间和因果依赖关系。然而，节点的移动性注入了一个新的空间维度的问题。在移动网络中，节点之间的物理距离和网络距离是不相关的。此外，移动的网络中的一些无线链路可以是单向的。因此，与物理距离不同，节点之间的网络距离不是对称关系。最后，如果两个移动的节点的请求基于它们各自距第三（资源）节点的距离而被优先化，则它们的相对优先级可以随时间改变。这与基于时间的事件的不可变的相对顺序形成对比。因此，如果距离是用于排序请求的标准之一，则用于诸如互斥（使用逻辑时钟）的问题的现有解决方案不能有效地用于移动的计算中的资源分配。我们将开发一个新的正式表示的时空之间的关系在移动的计算事件。时空矢量是朝这个方向迈出的一步。一个理论的基础上，他们的时空坐标的事件可能是不可变的排序将被开发。这样的请求排序可以用于资源无死锁、无饥饿和公平的资源管理。将在MAC子层开发新协议，使节点能够使用单向无线链路进行通信。我们将开发新的路由协议，利用这个MAC子层协议，并能正确路由数据包在无线移动的网络与单向和双向链路的组合。随后，这些解决方案的性能将通过仿真实验和原型进行评估。研究生和本科生将积极参与项目的每个阶段。

The goal of the proposed research is to develop a comprehensive understanding of the spatial aspect of distributed computing in mobile systems. Traditionally, events in a distributed computation are ordered by time. Scalar and vector clocks are used to represent logical time and causal dependencies. However, the mobility of nodes injects a new spatial dimension into the problem. The physical and network distances between nodes in a mobilenetwork are not correlated. Moreover, some wireless links in a mobile network may be unidirectional. Hence, unlike physical distance, the network distance between nodes is not a symmetric relation. Finally, if requests of two mobile nodes are being prioritized on the basis of their respective distances from a third (resource) node, their relative priority can change with time. This is in contrast to the immutable relative ordering of events based on time. Hence, if distance is one of the criteria for ordering requests, existing solutions for problems like mutual exclusion (using logical clocks) cannot be efficiently used for resource allocation in mobile computing. We will develop a new formal representation of the spatial-temporalrelationship between events in mobile computing. Space-time vectors are a step in this direction. A theory for a possibly immutable ordering of events based on their spatial-temporal coordinates will be developed. Such an ordering of requests could be used for resource deadlock free, starvation free and fair resource management. New protocols will be developed at the MAC sub-layer enabling nodes to communicate using unidirectional wireless links. We will develop new routing protocols that utilize this MAC sub-layer protocol, and can correctly route packetsin a wireless mobile network with a combination of unidirectional andbidirectional links.Subsequently, the performance of these solutions will be evaluatedthrough simulation experiments and prototyping. Graduate and undergraduate students will actively participate in every stage of the project.