Abiding geocast

Abiding geocast is a time stable geocast delivered to all nodes that are inside a destination region within a certain period of time. Services like position--based advertising, position--based publish--and--subscribe, and many other location--based services profit from abiding geocast. For vehicular ad hoc networks, abiding geocast allows realization of information and safety applications like virtual warning signs. Similar to real traffic or warning signs, they are attached to a certain geographical position or area. When a vehicle enters such an area, the virtual warning sign is displayed for the driver.This paper discusses the design space, the semantics, and three reasonable approaches for abiding geocast in an ad hoc network. The first one is a server solution to store the messages. The second approach stores the messages at an elected node inside the geocast destination region that temporarily acts as a server. The last one complements the exchange of neighbor information necessary for many unicast routing protocols with abiding geocast information.We compare the proposed protocols with a probabilistic network load and delivery success ratio analysis. The results show that the approaches with local message storage cause less network load. However, we also observed that in some cases the delivery success ratio of the approaches with local message storage is lower.