Energy-Autonomous Roadside Nodes in V2I Using RF Energy Harvesting

Future intelligent transportation systems will require complex networking infrastructures with communication among a huge number of vehicles and roadside nodes to support services such as autonomous driving. However, the deployment and operation of such a large number of roadside nodes is expensive due to either the cost of battery replacement or the maintenance of a continuous energy supply in long highways or rural areas. In this work, we evaluate the feasibility of a roadside unit harvesting energy from radio frequency (RF) signals transmitted by a nearby moving vehicle, with the incentive of using a part of the harvested energy to transmit small amounts of data to the vehicle. We consider a realistic model with the timing elements related to the movement of the vehicle, beam tracking errors, a non-linear model for energy harvesting, and potential line-of-sight obstructions in multi-vehicle scenarios. Results show that, with typical off-the-shelf components, it is feasible to use the RF harvested energy to transmit between a few hundred and several thousand bytes, depending on the speed of vehicles and the frequency of operation for energy harvesting, among other parameters.