Transmit Power Minimization in Bidirectional Tag-to-Device Communications for IoT

摘要

This paper explores a bidirectional communication scenario between a backscatter tag and an energy harvesting user in the presence of a multi-antenna energy transmitter. This hybrid user scenario provides the flexibility of optimizing our performance metric as the two techniques complement each other in achieving the desired objective. We measure the performance of the system in terms of the transmit power with an aim of minimizing it. This objective is achieved by solving a minimization problem over a joint set of constraints in energy transmit time, transmit power of the energy source, and a beamforming vector. Further, we analyze a special case where the source node is equipped with only a single antenna and leverage its analysis to achieve our overall aim, that is, the generalized case with a multi-antenna source node. Finally, the numerical results demonstrate a consensus with the analysis carried out for both the aforementioned cases.