Swarm Intelligence for Routing in Ad Hoc Wireless Networks

Ad hoc networks consist of autonomous self-organized nodes. Nodes use a wireless medium for communication, thus two nodes can communicate directly if and only if they are within each other’s transmission radius. Examples are sensor networks (attached to a monitoring station), rooftop networks (for wireless Internet access), and conference and rescue scenarios for ad hoc networks, possibly mobile. In a routing task, a message is sent from a source to a destination node in a given network. Two nodes normally communicate via other nodes in a multi-hop fashion. Swarm intelligence follows the behaviour of cooperative ants in order to solve hard static and dynamic optimization problems. Ants leave pheromone trails at nodes or edges which increases the likelihood of other ants to follow these trails. Routing paths are then found dynamically on the fly, using this so called notion of stigmergy. In this article we survey existing literature on swarm intelligence based solutions for routing in ad hoc networks. We identified 12 different methods, covering non-position and position based approaches, flooding and path based search methods. Some of the articles consider related problems such as multicasting or data centric routing. All of the articles were published after 2001. The ideas coming from existing swarm intelligence based routing in communication networks are incorporated into the wireless domain, with some new techniques which are typical for the wireless domain (such as flooding, use of position, monitoring traffic at neighbouring nodes) being incorporated. We observed that the experimental data provided by these articles is insufficient to make a firm conclusion about scenarios which show the advantages of the proposed swarm intelligence based methods with respect to other existing methods.