Performance Evaluation of Broadcast Communication Protocol DSCF (Directional Store-Carry-Forward) for VANETs with Two-Dimensional Road Model

In this paper, we reveal several characteristics of a broadcast communication protocol called DSCF (Directional-Store-Carry-Forward). In recent years, realization of VANETs (Vehicular Ad-hoc Networks) has been demanded for delivering information to vehicles at a low cost. In VANETs, a vehicle may or may not find other vehicles within its radio communication range because of vehicles' mobility, which results in frequently intermittent vehicle-to-vehicle radio communications. DTN (Delay Tolerant Networking) broadcast communication mechanisms can continue communication against intermittent vehicle-to-vehicle radio communications. Our previous work, we have proposed a DTN broadcast communication mechanism called DSCF. The effectiveness of DSCF in simple one-dimensional road models has been extensively studied. However, characteristics of DSCF in a realistic environment have not been investigated. In this paper, we therefore quantitatively examine several characteristics of the broadcast communication with DSCF in two-dimensional road models through simulation. In particular, four major characteristics of a broadcast communication in VANETs are investigated: dissemination speed, uniformity, reliability, and efficiency. Through extensive simulations, we show that DSCF performs quite effectively in terms of dissemination speed, uniformity, reliability, and efficiency unless the vehicle density is too low.