Reconfigurable passive relaying array for coverage enhancement

The use of decode-and-forward (DAF) and amplify-and-forward (AAF) relays with the purpose of receiving and re-transmitting information has long been proposed. Nonetheless, DAF relays increase latency and AAF relays suffer from inherent stability issues due to potential echoes on the relayed signal. Alternatively, a passive relaying array (PRA) is proposed as a means of coping with both of the so-mentioned drawbacks. The role of PRA is that of capturing and scattering energy in a desired direction. The current work proposes a closed-form model for a dipole-based PRA with an electronically tunable response. The validation of the proposed model and the link budget for communication through the relay are also shown. Furthermore, given the non-linear relationship of PRA on the electronically tunable loads, the simultaneous perturbation stochastic approximation (SPSA) method is used as a means of finding the set of loads that maximizes energy transfer in a desired direction.