Downlink and Uplink Transmission in K-Tier Heterogeneous Cellular Network with Simultaneous Wireless Information and Power Transfer

The emerging fifth-generation (5G) wireless communication system is expected to provide higher capacity, seamless connectivity and reduced energy consumption to support data intensive multimedia applications. Simultaneous wireless information and power transfer (SWIPT) in heterogeneous cellular networks (HCNs) is a promising approach to offer efficient spectrum and energy utilization in the 5G system. In this paper, we develop a tractable model for joint uplink (UL) and downlink (DL) transmission in a K-tier HCN with SWIPT. In this model, we use the power splitting (PS) protocol where the receiver splits the received signal power in two parts for harvesting the energy and decoding the information. The harvested energy in the DL is utilized for UL information transmission. We derive the exact analytical expressions for the average received power and the outage probability for both DL and UL for the system design. Monte carlo simulations confirm the accuracy of the derived results, and numerical analysis reveal that SWIPT is a reasonably efficient technique to power the cellular users. In particular, we observe that with the increase of the picocell density, both the DL and the UL outage probability in macrocell decreases significantly. Moreover, the DL and the UL outage probability in a tier is shown to decrease with the increase of BS transmit power of its own tier.