Development of Geocasting Protocols for a MANET

自组织网络涉及计算机，通常是无线移动节点，它们在没有特定用户管理或配置的情况下协作形成网络。换句话说，自组织网络允许移动节点的任意集合按需创建网络。这种能力在战术任务和救援行动以及教育和商业用途中有许多应用。由于需要形成自组织网络基础设施的应用的数量很多，因此这项技术的开发目前是NSF的研究重点。本提案中的工作涉及在自组织网络中提供Geocast通信的协议的开发和性能评估。地理广播协议的目标是将分组递送到指定地理区域内的一组节点，即地理广播区域。研究人员将开发和评估向明确定义的组(即，向已注册到组的Geocast区域中的移动节点提供Geocast)和隐式定义的组(即，向Geocast区域中的所有移动节点提供Geocast)两者提供Geocast通信的协议。研究人员还将考虑固定地理播送区域(即，由特定地理位置定义)和动态地理播送区域(即，由危险移动目标定义)。研究人员将开发和评估(通过模拟)三种不同的地理预测方法：定向泛洪方法、基于树的方法和基于网格的方法。他们还建议开发基于要传输的消息的性质和/或性能考虑的混合方法(例如，如果移动节点在最近过去一直移动缓慢，则可能不需要由基于网格的方法提供的冗余)。最后，研究人员计划在使用共享树或共享网状网方法时纳入可预测和可控制的端到端服务质量。在整个项目中，他们将进行广泛的模拟，以确定每种Geocast算法在什么条件下最有效。研究人员将改变模拟中的基本参数，以避免产生偏差的结果，例如网络规模、连通性、拓扑变化率和各种移动/呼叫模式。此外，模拟将考虑一些现实的限制，这些限制并不总是在以前的性能评估中得到解决，例如，广泛可用的消费者全球定位系统中存在的位置误差。拟议的项目是两名调查员之间的合作，他们拥有成功完成该项目所需的经验和能力。一名研究人员的专长是移动计算和网络领域。另一位研究人员的专长是开发模拟模型和评估协议的性能。在整个调查过程中，方法将从实际意义上进行。研究人员将参加互联网工程任务组的会议，以获得特别协议的当前状态并分享结果。

Ad hoc networking involves computers, typically wireless mobile nodes, that cooperatively form a network without specific user administration or configuration. In other words, ad hoc networking allows an arbitrary collection of mobile nodes to create a network on demand. This capability has numerous applications in tactical missions and rescue operations, as well as for educational and commercial use. Due to the number of applications desiring the formation of an ad hoc network infrastructure, development of this technology is currently a research priority at NSF. The work in this proposal concerns the development and performance evaluation of protocols that offer geocast communication in an ad hoc network. The goal of a geocasting protocol is to deliver a packet to a set of nodes within a specified geographical area, i.e., the geocast region. The researchers will develop and evaluate protocols that offer geocast communication to both explicityly defined groups (i.e., geocast to those mobile nodes in the geocast region that have registered with the group) and implicitly defined groups (i.e., geocast to all mobile nodes in the geocast region). The researchers will also consider both fixed geocast regions (i.e., defined by a specific geographical location) and dynamic geocast regions (i.e., defined by a dangerous moving target). The researchers will develop and evaluate (via simulation) three different approaches to geocasting: a directed flooding approach, a tree-based approach, and a mesh-based approach. They also propose to develop a hybrid approach that is based on the nature of the message to be transmitted and/or performance considerations (e.g., if the mobile nodes have been moving slowly in the recent past, then the redundancy offered by a mesh-based approach may not be needed). Lastly, the researchers plan to incorporate predictable and controllable end-to-end quality of service when a shared tree or shared mesh approach is used. Throughout the project, they will conduct extensive simulations to determine the conditions under which each of the geocast algorithms is most effective. The researchers will vary the essential parameters in the simulations to avoid biased results, e.g., network size, connectivity, topological rate of change, and various movement/calling patterns. In addition, the simulations will take into account some realistic limitations that have not always been addressed in prior performance evaluations, e.g., location errors that exist in widely available consumer Global Positioning Systems. The proposed project is a collaboration between two investigators who have the experience and capability necessary to complete the project successfully. The expertise of one investigator is in the mobile computing and networking area. The expertise of the other investigator is in the development of simulation models and the evaluation fo a protocol's performance. Throughout the investigation, the approach will be from a practical sense. The researchers will attend Internet Engineering Task Force meetings to obtain the current status of ad hoc protocols and to share the results.