Forwarding Angles and the Trade-Off Between Reliability, Latency and Unicast Efficiency in Content-Based Beaconless Forwarding

Receiver-based routing protocols are well suited for the Vehicular Ad-hoc Networks (VANETs) due to their ability that can make a routing decision on the fly. Forwarding zone is one of the key features in the receiver-based routing protocols in which a forwarding angle associated with a forwarding zone has a significant impact on the routing performance. However, the existing studies in this area have not focused much on the impact of a forwarding angle to the performance of the receiver-based routing protocols. This article presents a receiver-based routing protocol called Content-Based Beaconless Forwarding (CBBF) that utilizes the content in the header of a data packet while performing the routing operation. Specifically, CBBF uses location information to set a forwarding zone and the waiting time criterion. At the same time, other fields of the data packet's header are utilized to facilitate various mechanisms involved in the operation of CBBF. The impact of varying forwarding angles on the performance of CBBF is then studied and analyzed via simulations using QualNet. The simulations are carried out by varying the source transmission rate, node density and node velocity. The performance is evaluated in terms of packet delivery ratio (PDR), average end-to-end (ETE) delay and packet redundancy coefficient (PRC). From the simulation results, the CBBF with a forwarding angle of 60° offers the best trade-off between reliability, latency and unicast efficiency.