User association for load balancing in heterogeneous networks powered with energy harvesting sources

User association strategies for heterogeneous networks are proposed in order to balance the load among different base stations (BSs) and obtain higher downlink aggregate network utility based on per-user throughputs. The BSs are assumed to be solely powered with finite batteries and energy harvesting sources that allow them to collect energy from the environment and to recharge the batteries. Such battery limitations are considered explicitly in the proposed design. The simulations evaluate the effect of the energy harvesting capabilities on the network throughput and the comparison with other traditional strategies.