Design and Performance of Resonant Beam Communications -- Part I: Quasi-Static Scenario

TL;DR

This work addresses the challenge of achieving high-rate resonant beam communications in a quasi-static setting by mitigating echo interference with a synchronization-based amplitude modulation scheme. It maps the RBCom channel to a Markov process and then to a tractable amplitude-constrained AWGN model, enabling rigorous capacity bounds computed via a joint bisection-exhaustive-search algorithm. The authors derive a simplified channel with N parallel amplitude-constrained AWGN links and show that the optimal design is independent of the symbol index, yielding near-tight upper and lower bounds ($C_{up}$ and $C_{low}$) validated numerically. The results provide practical design guidelines for high-speed RBCom and lay the groundwork for the mobile scenario explored in Part II.

Abstract

This two-part paper studies a point-to-point resonant beam communication (RBCom) system, where two separately deployed retroreflectors are adopted to generate the resonant beam between the transmitter and the receiver, and analyzes the transmission rate of the considered system under both the quasi-static and mobile scenarios. Part I of this paper focuses on the quasi-static scenario where the locations of the transmitter and the receiver are relatively fixed. Specifically, we propose a new information-bearing scheme which adopts a synchronization-based amplitude modulation method to mitigate the echo interference caused by the reflected resonant beam. With this scheme, we show that the quasi-static RBCom channel is equivalent to a Markov channel and can be further simplified as an amplitude-constrained additive white Gaussian noise channel. Moreover, we develop an algorithm that jointly employs the bisection and exhaustive search to maximize its capacity upper and lower bounds. Finally, numerical results validate our analysis. Part II of this paper discusses the performance of the RBCom system under the mobile scenario.

Figures (16)

• Figure 1: Structure of RBCom system.
• Figure 2: Data transmissions across different frames.
• Figure 3: Schematic diagram of resonant beam propagation from the transmitter to the receiver.
• Figure 4: Schematic diagram of the resonant beam in the gain medium at the transmitter Rigord1.
• Figure 5: Link gain function $h(x_k(n))$ vs. transmitted symbol $x_k(n)$.