Mobile Intelligence

7.4 LOCATION SERVICE AND APPLICATIONS

On the basis of the clustering architecture, a multihop wireless network using the KCLS protocol is a distributed location service system, where each cluster head takes the responsibility of a location server to provide location information to its cluster members. In this case, the location enquiry from an orphan node is only forwarded to the nearest reachable cluster head. Hence, the KCLS protocol has much shorter latency for location searching than other location service protocols [6, 15], in which it may need to search the destination among several databases.

This distributed location service based on clustering architecture is reliable. Even in a case that some cluster heads are unreachable due to inter-cluster link failures, however, such failure only affects the relevant clusters, and the other clusters in the network are still active. Moreover, the transmission of data packet is still available even in the lack of the destination's accurate location information. This is because the location information in the packet header can be modified by intermediate cluster heads along the path to the destination. For example, when data packet faces inter-cluster link failure on its way to the destination, then this packet is forwarded to the nearest reachable cluster, where the cluster head modifies the location information contained in the packet that includes destination cluster ID, the coordinates of cluster head, and the sequence number. Then, ...