Intelligent reflecting surfaces adaptive beamsteering and PSK direct modulation

Intelligent Reflecting Surfaces (IRS), a planar ar�ray consisting of a large number of low-cost and low-complexitymetal patch elements, is predicted to be among the key technolo�gies in future wireless communications. This is mainly due to itscapability to improve wireless energy and spectrum efficiency byreconfiguring the wireless environment in a smart and flexibleway. IRS is capable of shifting the phase, amplitude, frequency,or even polarity of the impinging electromagnetic (EM) wave.However, only the phase-shift type of IRS is widely adoptedin most scenarios. In this paper, we exploit the property ofsuch IRS to directly modulate an incident EM wave with phase shift keying (PSK) modulation. We consider one transmitantenna that transmits a continuous single-tone electromagnetic(EM) wave, which is then modulated by the IRS and reflectedtoward the receiver. In addition to the theoretical explanation,we present simulation results with different modulation orders.Moreover, we validated the simulation results by experiment.Furthermore, we also proposed a beam scanning method toobtain IRS patterns to steer the beam towards the desired direction in an adaptive manner. One optimal pattern thatmaximizes the received power is then selected from the beam
scanning codebook. By doing so, a wireless path strength canbe significantly improved.