Improved junction-based routing for VANETs using a Bio-inspired route stability approach

The Junction-Based Routing (JBR) is established as the adequate solution to data packet routing within an urban Vehicular Ad Hoc Network (VANET). The latter is characterized by radio obstacles, unreadable traffic density change, and unstable vehicular mobility speed. Existing JBR routing protocols have not defined specific evaluation mechanisms to anticipate and detect stable road segments in large urban areas yet. Consequently, the connectivity of selected streets for data forwarding may not be regularly reliable for long periods, especially for remote destinations. As a matter of fact, stable long-lifespan JBR paths cannot be discovered; hence, generating low Packet Delivery Ratio (PDR) performances. In this paper, we introduce swarm-inspired optimization as a novel solution to reduce the number of lost data packets on the basis of a new route stability notion. A bio-inspired metaheuristic technique named the Intelligent Water Drops (IWD) algorithm is applied to track reactively and proactively the routing consistency of road segments. IWD seeks to gather accurately unreachable road segments' up-to-date connectivity information in order to predict progressively their stability degree. The latter is deduced according to predefined routing parameters featuring the history of route traffic and data forwarding, and vehicles' speed. These parameters are utilized to trace direct JBR paths to data packets' destinations with minimum disconnected road segments following IWD-inspired Dijkstra JBR paths. The proposed bio-inspired JBR protocol is compared to a few notable JBR schemes in a city map scenario. The simulation results showed a consistent mean PDR progress between 2.55% and 33.47% of all tested simulation variants.