Routing protocols

Abstract

A wireless sensor network (WSN) consists of hundreds or thousands of sensor nodes that are constrained in energy supply and bandwidth. Therefore, incorporating energy-awareness in all the layers of the protocol, stack is a basic requirement. Different sensor network applications generally require similar physical and link layers and the design of these layers is focused on system level power awareness such as dynamic voltage scaling, radio communication hardware, low duty cycle issues, system partitioning and energy aware MAC protocols (Heinzelman 2000; Min 2000; Woo 2001; Ye 2002; Eugene 2001). However, network layer gets influenced by the type of application besides ensuring energy-efficient route setup, reliable data-delivery and maximising network lifetime. Accordingly, routing in wireless sensor networks is nontrivial and should take into consideration its inherent features along with application and architectural requirements. The routing techniques are employed by contemporary communication and ad hoc networks cannot be applied directly to wireless sensor networks due to the following reasons: Traditional IP based protocols are inapplicable as it is infeasible to assign and maintain unique IDs for such a large number of sensor nodes As against a typical communication network nearly all the applications of WSNs require flow of data from several sources to one destination. Multiple sensor nodes within the vicinity of the sensed phenomenon might generate same data. In contrast to other networks, this fact can be exploited at the network layer to improve energy efficiency and bandwidth requirements. Sensor nodes have severe limitation on transmission power, energy reservoir, processing capability and storage that are not major issues in other networks. Sensor networks are application specific and the design requirement changes. Sensor networks are data-centric networks, i.e., they require attribute based addressing and queries are also formed in attribute-value pairs. For example, if a sensor network is queried with "temperature 60"then only the sensors with temperature greater then 60 will respond. © Springer-Verlag Berlin Heidelberg 2007.