The impact on throughput of hierarchical routing in ad hoc wireless networks

The purpose of this paper is to investigate the network throughput in ad hoc wireless networks (AHWN) under a cluster-based hierarchical routing scheme. Hierarchical routing has been known to handle the scalability issue in the AHWN. Such hierarchical routing protocols can reduce the routing overhead, as lesser nodes need to know topology information of an AHWN. Some works have studied the routing overhead of hierarchical base routing. However, there is little formal analysis that considers influence on the other network performance metric, e.g. throughput, incurred by these procedures. This paper provides a theoretical computation on the throughput of the AHWN under one hierarchical structure, i.e., cluster-based. It discusses the issue that the cluster head nodes may become the bottle neck for throughput, since the throughput of such AHWN is relatively smaller by a factor of O(N2/N1), N2 is the number of cluster-head nodes and N1 is the number of all the nodes in a network. Hence, there is a trade-off between the gain from routing overhead and loss from network throughput in the design of hierarchical routing for AHWN which need to be optimized.