Routing Protocols

The WISAR Lab addresses Wireless Sensor Network (WSN) routing protocols mostly in the context of Body Area Networks. Traditional Routing protocols have not been designed specifically for these cases and are usually designed to cover relatively large distances and for large numbers of nodes, which are not as resource constrained as those found in WSN's.

It is envisaged that the Body Area Network (BAN) will often consist of a hub (which may be a dedicated device and/or a mobile phone or PDA), with the wireless sensor devices communicating to that hub, which can then forward the data to other locations in a collated/aggregated or raw manner.

If the communication can be done in a single hop, then a simple star topology can be used, but multiple hops may be required due to constraints such as sensor power or location or factors such as multipath fading or shadowing. The use of a multiple hop approach may require less transmit power for each transmission (as it is directed to the next node on the route), but it adds overhead to establish/maintain these routes.

The ongoing research work of the WiSAR Lab includes

• investigating a range of routing protocols (flat-based or hierarchical and proactive, reactive, and hybrid) including LEACH, Power-Efficient Gathering in Sensor Information Systems (PEGASIS), Threshold-sensitive Energy Efficient Protocols (TEEN and APTEEN), Self Organizing Protocol (SOP) to assess their energy efficiency and ability to address the QoS issues.
• the comparison of MAC forwarding mechanisms against tree-based routing,
• inter-BAN routing (routing between the hubs of the networks),
• topology selection
• the development of link costs for path selection most suitable for BANs. 

A key consideration of this research is to address Quality of Service issues such as energy efficiency, reliability and latency given the harsh wireless working environment BANs operate under. For example, a Body Area Network's propagation conditions change continuously  and an energy aware routing protocol should react to those changes, but it should do so in a way that avoids being too active as this would increase the energy use of the motes. Meeting those such contradictory objectives means is a key goal of our research into routing protocols for WSNs.