SWIPT with Diplexer-based Multiple-Antenna Rectification

Simultaneous wireless information and power transfer (SWIPT), with the use of radio frequency (RF) signals, has been identified as one of the promising technologies for the Internet of Things (IoT). In order to practically achieve SWIPT the received RF signal is split in time, power or spatial domain. Even for the solution of the integrated SWIPT receiver, the converted direct current power signal is split in the power domain. As such a portion of the received signal is used for information decoding and the other for energy harvesting (EH). Recently, a scheme which achieves SWIPT without split of the resources, with the use of a diplexer at the receiver's side, was proposed. In this paper, we adopt this solution and we extend it to a diplexer-based SWIPT receiver, with multiple-antenna rectification circuits. As such we succeed SWIPT with enhanced performance, both in terms of symbol error rate and EH. We further compare the solution to the conventional integrated SWIPT receiver with multiple rectennas and prove the enhanced performance of the proposed solution. Non-coherent energy detection is succeeded with the use of a maximum-likelihood soft decoder, while the adopted modulation scheme is on-off keying (OOK). Furthermore, we investigate the effect of pulse energy modulation (PEM) in the system's performance. It is shown that PEM scheme enhances the performance in terms of EH, while lags behind in terms of information decoding, compared to OOK.