The wireless communications is studied for the intelligent connected vehicles (ICV) networks by supporting heterogeneous access with direct access of one vehicle yet the dual-hop access of another vehicle. The dual-hop access is enhanced by one dedicated vehicle as relaying vehicle with multiple antennas. The goal in this paper is to joint design of both receive beamforming and transmit beamforming at the relaying multi-antenna vehicle to suppress the interference between the two wireless receive vehicles yet match the dual-hop wireless channel as much as possible. The energy efficiency is optimized as the objective function under the constraint of the limited power over every beamforming vector. Due to the difficulty of the optimization, the principle of the signal to leakage plus noise ratio (SLNR) is introduced to the studied ICV networks and thus to obtain the analytical expression of the beamforming vectors. With the derived closed form over all the beamforming vectors, an iterative algorithm is developed for jointly optimizing all the beamforming vectors to maximize the energy efficiency of the whole system, which is guaranteed to be convergent to one local optimum. Numerical simulations show the good performances of the proposed method in ICV networks.
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