Station density effect on energy efficiency of relay-assisted cellular networks

The station density is believed to be a crucial factor that affects the energy efficiency of relay-assisted cellular networks dramatically, which can not be neglected for practical network design and planning. In this paper, we propose an analytical model to investigate how the station density affects the energy efficiency of relay-assisted cellular networks. With the aid of stochastic geometry theory, we derive the coverage probabilities and mean achievable rates of both cooperative users and non-cooperative users, and based on these, we further derive the analytical expression of energy efficiency and verify that by simulation. Numerical results show the significant improvement on energy efficiency brought by relays and that the energy efficiency presents a convex trend as the station density varies, which sheds key insights into the optimal densities of both base stations and relays with respect to energy efficient network deployment.