Self-Recycling in Multi-antenna Systems: Integrating RF Energy Harvesting in a Full-duplex Spatial Modulation System

Overview & Synopsis

In this paper, we propose a system that combines full-duplex spatial modulation (FDSM) and the radio frequency energy harvesting (RFEH) in a single system. FDSM is a multipleinput multiple-output (MIMO) technique that combines spatial modulation and full-duplex to perform higher spectral efficiency and low energy consumption. The proposed system aims at harvesting the part of the emitted power of the FDSM system that is naturally coupled to the surrounding antennas, to improve the overall energy efficiency of the system (concept of self-recycling). An array of four patch antennas, operating at 850 MHz, is considered and the focus is on two different antenna topologies: linear and circular. The impact of the spacing d between the center of the antenna elements on both the bit error rate (BER) and the level of harvested power is studied. A co-simulation in Matlab and ADS software was conducted and the results obtained from this study demonstrate a trade-off between these two criteria. It is observed that as the spacing d increases, the BER is enhanced, and the harvested power is reduced. For the linear topology, the optimal compromise is determined to be d = 0.5λ, where λ denotes the wavelength. For the circular topology, when λ< d <2λ, the BER begins to be acceptable, and the harvested power is higher.