Placement of multiple mobile data collectors in underwater acoustic sensor networks

We propose two schemes for routing and placement of mobile data collectors in Underwater acoustic sensor networks (UASNs): the delay tolerant placement and routing, (DTPR) and the delay constrained placement and routing (DCPR). As their names reveal, while the DTPR maximizes the lifetime of the network without any delay considerations, the DCPR maximizes the lifetime of the network With all upper bound on the maximum delay. Both schemes are based on a 3D architecture, in which on-the-surface data collectors gather data from underwater sensors and relay them to an on-shore sink. We divide the lifetime of the network into fixed length rounds and move the data collectors to new locations at the beginning of each round. These problems are formulated as integer linear programs (ILPs), and we use an ILP solver to find the optimal placement of data collectors together with the multi-hop routing paths to deliver data from underwater sensors to data collectors. Our work is a pioneering effort in the placement of mobile data collectors in three-dimensional UASNs. Comprehensive experiments show that our schemes prolong the lifetime of the network significantly as compared to other data collector placement schemes. Copyright (c) 2008 John Wiley & Sons, Ltd.