A study on improving the performance of ad hoc networks using location information

在自组织网络中使用的终端主要是便携式设备，其中支持LBS（基于位置的服务）。为了支持LBS，应该配备定位设备。由于它们的价格正在急剧下降，我们可以假设大多数终端都配备了它们。因此，利用终端的位置信息不仅可以提供LBS服务，还可以提高网络的连通性，这是非常合理的。从这个角度出发，我们研究了位置信息在ad hoc网络路由发现和其他操作中的使用。本研究的主要成果如下：当从源到目的的路径上存在障碍物时，传统路由的性能会下降。为了避免它们，我们引入了参考点的概念，并提出了一种绕过参考点的路由方法。在实验的基础上，我们提出了一个包含群体移动的新的移动模型。此外，通过使用它们，我们还开发了一个地理路线，如果行人的机动性是相关的，那么它就会很好地工作。开发了反映GPS时变实际定位误差的仿真工具。然后，在此平台上提出了一种存在定位误差的鲁棒地理路由方法。我们在测试系统上实现了上述路由算法，其中包括利用GPS和其他信息进行定位的功能。此外，我们提出了一种新的寻址方案，称为STA（时空地址），其中使用终端的位置和时间来表示终端的地址。STA非常适合于以数据为中心的通信。在测试中也实施了STA，我们正在更深入地研究和提高STA的有效性

The terminals used in ad hoc networks are mainly portable devisees, where LBS (Location Based Services) are supported. To support LBS, positioning devices should be equipped. Since the prices of them are radically decreasing, we may assume that most of the terminals are equipped with them. Therefore it is very rational to use the location information of terminals not only to provide LBS but also to enhance the network performance as connectivity.From this point of view, we studied the usage of location information for route discovery and other operations of ad hoc networks. The major results of the research are as follows.1. When obstacles exist on the route from the source to the destination, the performance of conventional routings is deteriorated. To avoid them, we introduced the concept of reference point and proposed a routing method to detour them.2. We measured the mobility of many pedestrians at the same time, and based on the experiment we proposed a new mobility model that includes the group mobility. Further, by using them, we also developed a geographical routing which works well if the mobility of the pedestrians is correlated.3. We developed a simulation tool where the time varying actual positioning error of GPS is reflected. Then, on this platform we proposed a robust geographical routing method where positioning error exists.4. We implemented the above routing algorithms on the tested system, which includes the localization function using GPS and other information. Further, we proposed a new addressing scheme called STA (Spatio Temporal Address) where the address of terminals are expressed by using the location and the time of the terminals. STA is very suitable for Data Centric communication. STA is also implemented on the tested and we are studying and improving the effectiveness of STA more intensively