  In this paper we consider a heterogeneous network which consists of a macro
base station and some pico base stations utilizing massive MIMO and MIMO
techniques, respectively. A central software-defined mobile network (SDMN)
controller is adopted in order to provide user association and energy
scheduling. The users are considered battery limited and are capable of
simultaneous wireless information and power transfer (SWIPT) in order to
harvest energy and address the energy shortage issue. These users harvest
energy from the received signals in the downlink and consume it via their
uplink communications. This paper deals with the downlink user association by
jointly optimizing the overall sum-rate of the network and the harvested energy
by introducing an appropriate utility function. In this regard, the optimum
user association and power splitting factor for each user are calculated via
the downlink optimization stage. Then, the process of uplink scheduling is
defined as choosing the best users in each time epoch to transfer data as well
as optimizing their transmit power by solving Lyapunov drift-plus-penalty
function. Simulation results are provided in order to confirm the optimality of
the proposed algorithm in comparison with the previous user association and
uplink scheduling approaches in terms of providing fairness and battery
management among users.
