Abstract-In this paper, we design a resource allocation algorithm for multiuser simultaneous wireless information and power transfer systems for a realistic non-linear energy harvesting (EH) model. In particular, the algorithm design is formulated as a nonconvex optimization problem for the maximization of the longterm average total harvested power at EH receivers subject to quality of service requirements for information decoding receivers. To obtain a tractable solution, we transform the corresponding non-convex sum-of-ratios objective function into an equivalent objective function in parametric subtractive form. This leads to a computationally efficient iterative resource allocation algorithm. Numerical results reveal a significant performance gain that can be achieved if the resource allocation algorithm design is based on the non-linear EH model instead of the traditional linear model. is an appealing solution for enabling self-sustainable wireless devices in communication networks. Thereby, the inconvenience of recharging and replacing batteries can be avoided by harvesting energy from different energy sources, such as solar and wind. Recently, wireless power transfer (WPT) via radio frequency (RF) signals has received considerable attention as it provides an ubiquitous, relatively stable, and controllable source of energy [1], [2] . Moreover, additional benefits can be reaped by employing informationcarrying signals for WPT, which enables simultaneous wireless information and power transfer (SWIPT) [3] . SWIPT introduces a paradigm shift for system, receiver, and resource allocation algorithm design for communication systems due to the newly imposed challenges in delivering information and energy concurrently. In particular, there is a fundamental trade-off between EH and information decoding (ID), as was shown in [3] . Thereby, resource allocation plays a particularly important role for improving the system performance of SWIPT networks. In [2], the authors proposed a power allocation algorithm for near-field communication systems. However, the authors of [2] and [3] assumed that the receivers are able to harvest energy from the received signal, while simultaneously decoding the embedded information, which is not feasible in practice, yet, due to practical limitations of EH circuits. Consequently, hybrid power splitting receivers and separate receivers were proposed for SWIPT in [4] and [5], respectively. Additionally, a simple time-switching receiver was proposed for alternating between ID and EH across different time slots [4] . For multiuser downlink SWIPT systems, suboptimal order-based scheduling schemes to balance the trade-off between the ergodic achievable rates and the average amounts of harvested energy of the users were proposed in [6] . Furthermore, adopting the same system model as in [6] ,
Based on this practical EH model, the authors proposed an optimal resource allocation strategy in a SWIPT system where all devices equipped with a single antenna REF .
Power Allocation and Scheduling for SWIPT Systems with Non-linear Energy Harvesting Model
2016 IEEE International Conference on Communications (ICC)
2016 IEEE International Conference on Communications (ICC)
Computer Science Mathematics