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

自组织网络中使用的终端主要是便携设备，其中支持LBS(Location Based Services)。为支持LBS，应配备定位设备。由于它们的价格正在急剧下降，我们可以假设大多数航站楼都配备了它们。因此，利用终端的位置信息不仅可以提供LBS，还可以提高网络的连通性，这是非常合理的。从这一角度出发，我们研究了利用位置信息进行自组网的路由发现等操作。主要研究成果如下：1.研究成果。当从源点到目的地的路线上存在障碍时，传统路线的性能会恶化。为了避免这些问题，我们引入了参考点的概念，并提出了一种绕过参考点的路径选择方法。我们同时测量了多个行人的流动性，并在实验的基础上提出了一种新的包含群体流动性的流动性模型。此外，通过使用它们，我们还开发了一种地理路线，如果行人的流动性与之相关，则该路线工作得很好。我们开发了一个反映GPS实际定位误差时变的仿真工具。然后，在该平台上提出了一种存在定位误差的稳健地理布线方法。在被测系统上实现了上述路由算法，包括利用GPS等信息进行定位的功能。在此基础上，我们提出了一种新的寻址方案--STA(Spatio Temporal Address)，它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。在测试平台上也实现了STA，我们正在更加深入地研究和提高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