An evolutionary approach towards contact plan design for disruption-tolerant satellite networks.pdfVIP

Applied Soft Computing 52 (2017) 446–456 Contents lists available at ScienceDirect Applied Soft Computing journal homepage: /locate/asoc An evolutionary approach towards contact plan design for disruption-tolerant satellite networks Juan A. Fraire a,?, Pablo G. Madoery a, Jorge M. Finochietto a, Guillermo Leguizamón b a Universidad Nacional de Córdoba – CONICET, Córdoba, Argentina b Universidad Nacional de San Luis, San Luis, Argentina article info Article history: Received 5 April 2016 Received in revised form 15 October 2016 Accepted 17 October 2016 Available online 22 October 2016 Keywords: Delay tolerant networks Contact plan design Evolutionary algorithms abstract Delay and disruption tolerant networks (DTNs) are becoming an appealing solution for satellite networks where nodes can temporarily store and carry in-transit data until a link with a suitable next-hop becomes available. Since satellite trajectories and orientation can be predicted, on-board routing schemes can base these forwarding decisions on a contact plan comprising all forthcoming communication opportunities. In general, contact plans are previously calculated on ground where their design can be optimized to con- sider not only available spacecraft resources but also the expected traf?c which is largely foreseeable in space applications. Despite optimal contact plan design procedures exist, their computation complexity might result prohibitive even for medium-sized satellite networks. In this work, we propose an evolu- tionary algorithm to provide sub-optimal yet ef?cient and implementable contact plans in bounded time. In particular, we depict speci?c strategies such as encoding and repairing techniques to later evaluate the algorithm performance in a typical scenario demonstrating its usefulness for planning future DTN-based satellite networks. ? 2016 Elsevier B.V. All rights reserved. 1. Introduction Today, optical and radar images are acquired continuously from orbit as they enable better un