Design, implementation and evaluation of protocol stacks for sensor networks
Optimization of sensor networks performance through sink mobility
This activity stems from the observation nodes around the sink tend to transmit/receive more packets, fast deploying their available energy and isolating the sink from the rest of the network. A way to load balance energy consumption among the network nodes is via relay or sinks mobility. The activity carried out has resulted in scalable models which output sojourn times of the sink at different sites, as well as the sink movement which maximize the network lifetime. Both the single sink and the multi-sink cases have been considered. Distributed solutions which achieve performance close to the optimum have also been designed.
Design of complete, cross-layer optimized protocol stacks for terrestrial wireless sensor networks.
Three different stacks have been designed, evaluated, implemented and tested: ROME, ALBA-R and IRIS. They do not require any knowledge of the neighborhood of a node, do not require exchange of information between pairs of neighboring devices unless there is the need to transmit data traffic.
ROME is a geographic routing protocol for wireless sensor networks (WSNs) with mobile nodes. ROME design is suited to deal with communication problems in WSN scenarios with high network dynamics, such as nodal addition, nodal removal and node mobility. In addition, it retains desirable properties of protocols for static WSNs such as using cross-layer techniques for performance optimization, dealing with asynchronous nodal duty cycles, and being able to deal with connectivity dead ends.
ALBA-R is a solution for convergecasting in wireless sensor networks. ALBA-R features the crosslayer integration of geographic routing with contention-based MAC for relay selection and load balancing (ALBA) as well as a mechanism to detect and route around connectivity holes (Rainbow). ALBA and Rainbow (ALBA-R) together solve the problem of routing around a dead end without needing high-overhead techniques such as graph planarization and face routing. The protocol is fully localized and distributed, is highly adaptive to variations in traffic and to different node deployments.
IRIS is a cross-layer protocol for WSNs that integrates different desirable features: awake/asleep scheduling, interest dissemination, cross layer convergecasting, data fusion, adaptive duty cycle and estimation of the number of neighbors of each sensor node. IRISI TinyOS implementation will be made available soon.
We have also developed robust, energy-efficient interest dissemination schemes. Fireworks exploits topology graph properties to perform reliable probabilistic flooding.
Design of schemes for backbone formation in ad hoc and wireless sensor networks
The activity has focused on 1) comparing major solutions so far proposed identifying which features or approaches are required for realistic deployments. A simulation framework has been developed to perform such evaluation and has been made available to the scientific community (see sw and test-bed section of these pages); 2) designing improved solutions for backbone formation. Activities have in particular focused on the design of schemes which are resilient to nodes failures and that lead to low overhead and fast backbone reorganization.
Development of tools for managing a wireless sensor networks test-bed
Tools have been developed to monitor the performance of indoor, cabled test-beds, as well as for monitoring the performance of real-life test-beds.
We have developed a Wireless Sensor Network Test-bed Management System, called JAMES (JAva test-bed ManagEment System). JAMES is a complete system to remotely manage a pool of federated test-beds, schedule tests, gather and analyze results, supporting fair comparative performance evaluation of different protocols and of a protocol in various settings.
- "ALBA-R: Load-Balancing Geographic Routing Around Connectivity Holes in Wireless Sensor Networks", IEEE Transactions on Parallel and Distributed Systems, March, 2014, pp. 529 - 539.
- "IRIS: Integrated data gathering and interest dissemination system for wireless sensor networks", Elsevier Ad Hoc Networks, Vol. 11, March, 2013, pp. 654 - 671.
- "Coordinated and Controlled Mobility of Multiple Sinks for Maximizing the Lifetime of Wireless Sensor Networks", ACM/Springer Journal on Wireless Networks (WINET), January, 2011.
- "ROME: Routing Over Mobile Elements in WSNs". Proceedings of IEEE GLOBECOM 2009. Honolulu, Hawaii, USA : IEEE Computer Society. 30 November -- 4 Dec. 2009.
- "Controlled Sink Mobility for Prolonging Wireless Sensor Networks Lifetime", ACM/Springer Journal on Wireless Networks (WINET), Vol. 14, December, 2008, pp. 831-858.