Green resource allocation for powerline communications

The growth in energy demand coupled with global warming provide new trends in communication systems known as green radio. In this paper, we focus on energy minimization for powerline communications. The transmitted consumed energy is minimized in the case of point to point transmission link using parallel channels. The transmission of data, that corresponds to a finite number of bits, can be performed with slight delay constraint. We make the assumption that this constraint is completely relaxed. In this case, the minimization of the consumed transmitted energy leads to infinite time of transmission. To overcome this drawback of infinite time of transmission, the operating point of communication system is defined under energy efficiency constraint. This energy efficiency is the ratio between the energy lower bound and the transmitted energy consumed by the system. The goal is then to find the bit and the associated energy distributions among parallel channels for a given energy efficiency. The problem is solved in the case of uniform spectral efficiency and uniform bandwidth for all channels. The solution given by convex optimization tools leads to uniform bit distribution among a subset of channels. A low complex algorithm is proposed to provide the optimal solution. Simulation results are performed for powerline communications over Zimmermann channel and show that a gain factor of 500 in energy saving is reached while the time of transmission is only multiplied by 10. This green resource allocation strategy provides a huge energy gain for powerline communications with a small increase of the transmission time.