A delay-bounded routing protocol for vehicular ad hoc networks with traffic lights

In vehicular ad hoc networks, vehicles may use a routing protocol to inform emergent events, e.g. car accidents or traffic jams. Hence, many of the researchers are focus on minimizing the end-to-end delay of the routing protocol. However, some applications, e.g. email or ftp, are not time critical and radio spectrum is a limited resource. Hence, delay-bounded routing protocol, whose goal is to deliver messages to the destination within user-defined delay and minimize the usage of radio, has become an important issue. The delay-bounded routing protocols deliver message to the destination by the hybrid of data muling (carried by the vehicle) and forwarding (transmitted through radio). When the available time is enough, the message will be delivered by muling, otherwise, it will be delivered by forwarding. However, in an urban area, there are many traffic lights, which may greatly affect the performance of the delay-bounded routing protocols. Existing works do not consider the effect of traffic lights and hence it may adopt an improper delivery strategy and thus wastes a lot of available time. To improve previous works, we propose a novel delay-bounded routing protocol which has considered the effect of traffic lights. Whenever a vehicle pass an intersection, it will gather the information of traffic light and traffic load of the next road section and thus it can make a more accurate prediction and adopt a more proper strategy to deliver message. Simulation results show that the proposed protocol can make a better usage of the available time and uses less radio resource to deliver the message in time.