Experimental demonstration of free-space information transfer using phase modulated orbital angular momentum radio

TL;DR

This paper demonstrates in real-world urban conditions that radio beams with orbital angular momentum can be phase modulated to transfer information effectively, showing potential for advanced wireless communication.

Contribution

It provides the first real-world experimental validation of digital phase shift modulation of OAM radio beams for information transfer.

Findings

OAM radio beams can be phase modulated for data transfer

The method is robust against reflections and interference

Compatible with existing digital communication protocols

Abstract

In a series of fundamental proof-of-principle experiments, comprising numerical, controlled laboratory, and real-world experimentation, we have shown that it is possible to use the angular momentum physical layer for radio science and radio communication applications. Here we report a major, decisive step toward the realization of the latter, in the form of the real-world experimental demonstration that a radio beam carrying orbital angular momentum (OAM) can readily be digitally phase shift modulated and that the information thus encoded can be effectively transferred in free space to a remote receiver. The experiment was carried out in an urban setting and showed that the information transfer is robust against ground reflections and interfering radio signals. The importance of our results lies in the fact that digital phase shift keying (PSK) protocols are used in many present-day wireless communication scenarios, allowing new angular momentum radio implementations to use methods and protocols that are backward compatible with existing linear momentum ones.