Routing Protocols for Dense Wireless Sensor Networks: Characteristics and Challenges

Wireless Sensor Networks WSNs are emerged as effective network types which mainly depend on employing very small manufactured sensor nodes to aggregate the environmental data and then transfer it toward the concerned node. Some tactical applications such as medical, military, monitoring, emergency, and others require high density of WSN in limited area. Dense WSNs is a special type of WSNs in which very large density for the deployed nodes and also for the exchanged data are considered. Routing process in DWSNs requires special design due to its unique characteristics and requirements. This paper investigates the characteristics, design and challenges in routing protocols of DWSNs. Furthermore; the paper classifies the routing protocols based on different criteria. The paper ends up with an evaluation of several hierarchal and flat-based routing protocols based on different performance criteria. Finally some open research areas, conclusion remarks and future works are presented.