title: Routing protocols in wireless sensor networks.
abstract: The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks.
authors.affiliation: Group of Analysis, Security and Systems (GASS), Department of Software Engineering and Artificial Intelligence, School of Computer Science, Office 431, Complutense University of Madrid (UCM), Calle Profesor José García Santesmases s/n, Ciudad Universitaria, 28040 Madrid, Spain; E-Mails:  asandoval@fdi.ucm.es  (A.S.);  atrica@fdi.ucm.es  (A.T.);  cbarenco@fdi.ucm.es  (C.B.).
authors.forename: Luis Javier García
authors.initials: LJ
authors.lastname: Villalba
authors.forename: Ana Lucila Sandoval
authors.initials: AL
authors.lastname: Orozco
authors.forename: Alicia Triviño
authors.initials: AT
authors.lastname: Cabrera
authors.forename: Cláudia Jacy Barenco
authors.initials: CJ
authors.lastname: Abbas