Subcarrier Allocation of Cognitive OFDM Systems with SWIPT-Enabled Relay

Cognitive radio (CR), as an intelligent spectrum sharing technology, can improve utilization of spectrum. Simultaneous wireless information and power transfer (SWIPT) is harvesting energy from ambient RF signals and makes full use of RF signals. Orthogonal frequency division multiplexing (OFDM) can allocate subcarrier flexibly and the transmission power on the subcarrier can be controlled. In this paper, we utilize subcarrier allocation method to dispose the interface at receiving end for cognitive OFDM systems.