RIS-Based Reconfigurable Antenna for Anti-Jamming Communications with Bit-Limited ADCs

In the future of high-frequency communications, the jamming on multipath will pose a serious threat to the system. This paper explores the potential of reconfigurable intelligent surfaces (RIS) based reconfigurable antenna (RA) in anti-jamming communications with bit-limited analog-to-digital converter (ADC). To deal with the multipaths jamming and the signal blocking problem caused by the ADC, we first propose a reconstruction method to obtain the covariance matrix of the received signal with lower signal blocking probability. Second, we propose anti-jamming schemes based on the physical properties of RAs with continuous and discrete phase shifts, respectively. For the continuous-RA, an algorithm based on the semidefinite programming is proposed to find the optimal unit-modulus phase shifts. For the discrete-RA, RIS elements are rapidly switched to expand the adjustable range and approximate the optimal unconstrained weighted value. Simulation results verify that the proposed schemes can improve the jamming immunity at a lower cost, and the discrete- RA is more suitable for the scenarios of strong jamming and bit-limited ADCs.