Joint Downlink and Uplink Resource Allocation for Multi-user Multi-carrier Simultaneous Wireless Information and Power Transfer Systems

Simultaneous Wireless Information and Power Transfer (SWIPT) is an effective technique to solve the energy limitation problem of wireless networks. A multi-carrier SWIPT communication system that includes one Base Station (BS) and multiple users is investigated. Both the uplink and downlink of the system apply the OFDM transmission. In the downlink, the BS transmits information and power over different subcarriers to the users simultaneously. In the uplink, the user transmits information to the BS by using the power harvested from the BS in the downlink. This paper aims to maximize the weighted sum of the downlink and uplink achievable rates by jointly optimizing subcarrier allocation and power allocation of the uplink and downlink. An optimal algorithm is proposed to solve this resulted optimization problem, which is based on the Lagrange duality method and the ellipsoid method. The performances of the proposed algorithm are verified by computer simulations.