Access Points Grouping Scheme with Energy and Time Allocation in EH-based UDN

With the increasing requirements of uplink (UL) data transmission from emerging applications such as virtual reality, ultra dense network (UDN) has been proposed as an effective solution to support high data rate and massive connections in hot spot areas. With short distance between access points (APs) and user terminals, multiple APs may cooperate as a group to provide the access service for a user. Due to the high energy consumption for accessing to multiple APs, energy harvesting (EH) technology is introduced into UDN. We propose a novel APs grouping and resource allocation scheme to maximize the throughput via jointly optimizing energy and time allocation of downlink (DL) and UL in EH-based UDN. In order to ensure that the user’s energy harvested from APs is sufficient to transmit data, we present a probability function with the energy relationship of DL and UL to jointly optimize the EH range and the time allocation. Moreover, the APs are divided into groups based on the EH range obtained by the function. Particle swarm optimization (PSO) algorithm is adopted to derive the optimal solution of the formulated power allocation problem for the selected APs. Simulation results show that the proposed scheme has better performance compared with existing APs grouping schemes.