  With the rapid development of vehicular networks, various applications that
require high computation resources have emerged. To efficiently execute these
applications, vehicular edge computing (VEC) can be employed. VEC offloads the
computation tasks to the VEC node, i.e., the road side unit (RSU), which
improves vehicular service and reduces energy consumption of the vehicle.
However, communication environment is time-varying due to the movement of the
vehicle, so that finding the optimal offloading parameters is still an open
problem. Therefore, it is necessary to investigate an optimal offloading
strategy for effective energy savings in energy-limited vehicles. In this
paper, we consider the changes of communication environment due to various
speeds of vehicles, which are not considered in previous studies. Then, we
jointly optimize the offloading proportion and uplink/computation/downlink bit
allocation of multiple vehicles, for the purpose of minimizing the total energy
consumption of the vehicles under the delay constraint. Numerical results
demonstrate that the proposed energy-efficient offloading strategy
significantly reduces the total energy consumption.
