Performance Evaluation of Epidemic Broadcast with Directional Antennas in Vehicular Ad-Hoc Networks

In this paper, we extensively investigate the effectiveness of an epidemic broadcast with directional antennas on two-dimensional road model. In VANETs, realization of broadcast communication from a vehicle to other vehicles solely using a vehicle-to-vehicle radio communication channel is desired. In our previous work, we have proposed DSCF (Directional Store-Carry-Forward), which is an epidemic broadcast with two directional antennas. DSCF is a simple epidemic broadcast but it intentionally utilizes two directional antennas for directed message delivery for alleviating the broadcast storm problem. In this paper, we extensively investigate the effectiveness of DSCF on two-dimensional road a model in terms of reach ability, dissemination speed, uniformity, and efficiency. The performance of DSCF is thoroughly compared with that of P-BCAST, which is one of the simplest epidemic broadcasts with an omni directional antenna. In theory, P-BCAST achieves the optimal reach ability, dissemination speed, and uniformity while compromising the worst efficiency. Our findings include that DSCF can achieve satisfactory reach ability and dissemination speed comparable to those of P-BCAST with significantly better efficiency, which implies favorable characteristics of directional antennas for epidemic broadcasts in VANETs.