Tianyi Lin Jun Du 0001 Haijun Zhang 0001 Arumugam Nallanathan Jun Wang 0012 PPO-Based Energy-Efficient Power Control and Spectrum Allocation in In-Vehicle HetNets. 6334-6339 2023 GLOBECOM https://doi.org/10.1109/GLOBECOM54140.2023.10437468 conf/globecom/2023 db/conf/globecom/globecom2023.html#LinDZNW23