Examining transmission power in minimum capacity underwater acoustic networks

Abstract

This paper explores the prospect of reducing the transmission power required to operate links within an underwater acoustic network by minimizing the total capacity of the network while maintaining certain data flow requirements. This is motivated by an approximate model for underwater acoustic transmission power that demonstrates that decreasing the distance between nodes, the capacity of a link between nodes, or both, reduces the power required to send a signal between those nodes. A procedure for determining a minimum-sum capacity network developed by Gomory and Hu in 1961 is applied to several common network topologies including tree, ring, and mesh structures. The approximate model for transmission power, which takes into account the large effects of signal attenuation and noise, is used to evaluate these minimal networks. The networks derived from the Gomory-Hu procedure are shown to require less total transmission power to operate the entire network. In order to maintain the pre-set data flow requirements in the Gomory-Hu network, it is necessary to send information across multiple parallel paths in the network. Results show that because of this extra transmission distance, the networks derived via the Gomory-Hu procedure and their consequent parallel routing schemes are less efficient in terms of a single-transmission from one node to another node in the network than their counterpart networks that operate via a direct-access method, although the transmission power requirements per node are reduced. This parallel routing scheme implies that the Gomory-Hu networks could be beneficial for multi-cast transmission. Results show that applying the Gomory-Hu procedure to networks intended for multi-cast instead of single-cast transmission could be a promising way of increasing the efficiency of the overall network.