Route planning is considered as one of the fundamental technologies in the navigation system, which finds an optimal route between a pair of source and target locations. Navigation services are required to provide real-time responses to route planning queries to promote user experiences on the road under different situations, such as sudden detour, unpredictable traffic congestion and loss of GPS signals. However, most commercial navigation products search the optimal path at the remote central server which suffer from several inherent limitations. First, the communication between the access network and the remote central server has a large uncertain Internet-induced time delay. Second, the computational cost of retrieving an optimal path is increasing exponentially with the distance from the source location to the destination in a large-scale road network. To address the above issues, we propose a real-time Cache-Aided Route Planning System based on Mobile Edge Computing (CARPS-MEC), aiming to greatly shorten the communication and computation time of route planning queries by caching those frequently requested paths. Different from traditional cache based route planning algorithms which require an exact path matching from point to point, CARPSMEC makes a rough path matching from region to region. Thus, it only needs to process unmatched road segments on a MEC server which is closer to the end users. This will significantly reduce the transmission latency due to the uncertainty of the Internet. Experiment results demonstrate that CARPS-MEC can increase the cache hit ratio and reduce the response time greatly.

中文翻译：

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基于移动边缘计算的实时缓存辅助路由规划

路线规划被认为是导航系统中的基本技术之一，它可以在一对源位置和目标位置之间找到一条最佳路线。需要导航服务来提供对路线规划查询的实时响应，以促进用户在不同情况下在道路上的体验，例如突然绕道，不可预测的交通拥堵和GPS信号丢失。但是，大多数商业导航产品都在远程中央服务器上搜索最佳路径，这受到一些固有的限制。首先，访问网络和远程中央服务器之间的通信具有很大的不确定性，它是Internet引起的时间延迟。第二，在大规模道路网络中，检索最佳路径的计算成本随着从源位置到目的地的距离呈指数增长。为了解决上述问题，我们提出了一种基于移动边缘计算的实时高速缓存辅助路由规划系统（CARPS-MEC），旨在通过缓存那些经常请求的路径来大大缩短路由规划查询的通信和计算时间。与传统的基于缓存的路线规划算法需要点到点的精确路径匹配不同，CARPSMEC会进行从区域到区域的粗略路径匹配。因此，它只需要在距离最终用户更近的MEC服务器上处理不匹配的路段。由于互联网的不确定性，这将大大减少传输延迟。