Wireless Information and Power Transfer in Single User OFDM Systems

In this article, OFDM-based single-user simultaneous wireless information and power transfer (SWIPT) system for power splitting (PS) and time switching (TS) plans is analyzed. The optimal design for resource allocation (i.e., power allocation and subcarrier assignment) is investigated in order to maximize the sum rate with a minimum transferred power constraint. By extending power allocation and time division to more spans, two new schemes TPS2 and TPS1 which are obtained by appropriate combination of TS and PS will be analyzed and simulated. In proposed method, we will divide the time frame of data transfer into more subintervals that are equipped with power split hardware. The problem of transferring information in this system becomes a constraint convex optimization problem. By solving this non-convex optimization problem with mathematical methods, increase in the rate of information transfer can be found comparing to the conventional schemes. Results are presented as the rate of information transfer in terms of different values of the minimum required harvested energy. Simulation results show that the proposed method, i.e. PTS2, has about 11% superiority in comparison with conventional PS and TS schemes in the data transfer rate for the same energy harvesting value. Also in this method, with the increase in the number of sub-intervals an ideal simultaneous transmission can be achieved, in which energy harvesting will not lead to reduction in any data transfer rate.