Optimal Pricing with Wireless Powered Communication Network for Energy Saving

This paper studies cooperation between two users in a wireless powered communication network (WPCN) with a pricing mechanism for energy saving. First, a two-user WPCN of one hybrid access point (H-AP) with a constant power supply is considered, while in the downlink (DL), wireless energy is transmitted to two users and in the uplink (UL) individually harvested energy is used to transmit independent information from users to the H-AP. Based on the "doubly near-far" phenomenon, a WPCN with user cooperation is proposed where the near user (U2) uses harvested extra energy to help the far user (U1) to relay information to the H-AP. Furthermore, a pricing mechanism is proposed to incentivize uplink cooperative communications to achieve energy saving for the far user (U1). In the ideal case with full cooperation, the payment of U2 equals the energy used by U1 to relay information. However, with partial cooperation, U2 expects to receive extra reward. This paper formulates the U1's pricing and relay data in an ideal case and also considers the communication mode selection and cooperation distance constraints. Finally, numerical simulation results show that the proposed cooperative communication of WPCN with pricing can significantly the decrease far user's expected cost and can also increase the reliability of user's communication in WPCN.