Topology Control in Hybrid VLC/RF Vehicular Ad-Hoc Network

Vehicular ad-hoc network (VANET) is a promising technology to realize communications among vehicles in intelligent transportation systems. Conventional VANET utilizes radio frequency (RF) for vehicle to vehicle communications. However, as the vehicle density increases, RF-based VANET suffers from limited bandwidth and unavoidable interference. Visible light communication (VLC) is emerging as a complement candidate, which possesses the advantages of wide spectrum, high power efficiency and low interference, but also has the drawback of limited communication range. Therefore, the hybrid VLC/RF structure is beneficial to an efficient and reliable VANET. Since there are usually no center infrastructures in VANET and different vehicles could have different preferences, the distributed and non-cooperative topology control (TC) should be investigated for the establishment of VLC and RF links among various vehicles to satisfy some properties, e.g., interference level, power consumption, connectivity and delay requirements. Conventional TC schemes designed particularly for RF-based ad-hoc network can not be applied directly due to the distinctive features of VLC and RF links. In this paper, the TC problem for the hybrid VLC/RF VANET is modeled as a potential game. When considering the different features of the two kinds of links, a distributed TC algorithm is proposed to handle the TC game, in which the RF and VLC transmitting power of each vehicle is locally adapted based on the vehicle's local knowledge about the VANET topology and can converge to a Nash Equilibrium state.