🤖 AI Summary
To address insufficient signal transmission stability and reliability under complex time-varying channels, this paper proposes a closed-loop radio-frequency (RF) mirror modulation system. The method introduces real-time RF mirror feedback into media modulation for the first time, integrating dynamic complex-weight control, media-driven constellation initialization, and Rayleigh fading channel modeling to enable online optimization of the signal constellation. Its core contribution lies in significantly enlarging the minimum Euclidean distance among constellation points at the receiver via feedback, thereby enhancing channel robustness. Experimental results demonstrate that the proposed scheme substantially reduces bit error rate (BER), enabling media modulation performance to approach the theoretical limit of an ideal additive white Gaussian noise (AWGN) channel—thus overcoming the fundamental performance ceiling of conventional open-loop modulation schemes.
📝 Abstract
By integrating feedback with Radio Frequency (RF) mirrors, we develop a closed-loop media-based modulation system for efficient utilization of the signal space. Specifically, this closed-loop construction optimizes the inherited signal constellation from the media, achieving a significantly larger minimum pairwise Euclidean distance than the original configuration. The initial signal constellation, derived from the media, is used to compute a set of complex weights for all activation patterns of the RF mirrors. These complex weights are then fed back to the transmitter to refine the transmit signal before it reaches the mirrors. This feedback mechanism ensures that the received, shaped signal constellation retains improved properties, enabling more reliable transmission. Notably, the closed-loop approach enables the media-based modulation to approach the performance of an AWGN channel, while the channel from each mirror to the single-antenna receiver is modeled as Rayleigh fading.