A constraint programming approach to the additional relay placement problem in wireless sensor networks

• Published in: Constraints : an international journal Vol. 20; no. 4; pp. 433 - 451
• Main Authors: Quesada, Luis, Sitanayah, Lanny, Brown, Kenneth N., O’Sullivan, Barry, Sreenan, Cormac J.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2015
• Subjects: Artificial Intelligence; Computer Science; Operations Research/Decision Theory; Optimization; Node disjoint paths; Wireless sensor networks; Constraint optimisation problem; Network deployment planning; Relay placement
• ISSN: 1383-7133; 1572-9354
• DOI: 10.1007/s10601-015-9188-8

A Wireless Sensor Network (WSN) is composed of many sensor nodes which transmit their data wirelessly over a multi-hop network to data sinks. Since WSNs are subject to node failures, the network topology should be robust, so that when a failure does occur, data delivery can continue from all surviving nodes. A WSN is k -robust if an alternate length-constrained route to a sink is available for each surviving node after the failure of up to k -1 nodes. A WSN is strongly k -robust if there are k disjoint length-constrained routes to a sink for each node. Determining whether a network is k -robust is polynomial. However, determining whether a network is strongly k -robust is an NP-complete problem. We develop a Constraint Programming (CP) approach for deciding strongly k-robustness that outperforms a Mixed-Integer Programming (MIP) model on larger problems. A network can be made (strongly) robust by deploying extra relay nodes. We extend our CP approach to an optimisation approach by using QuickXplain to search for a minimal set of relays, and compare it to a state-of-the-art local search approach.