Joint communication and sensing with structured beams carrying orbital angular momentum

Area of Science:

• Physics
• Electrical Engineering
• Wireless Communications

Background:

• Electromagnetic beams with orbital angular momentum (OAM) offer helical phase structures and doughnut intensity profiles, suitable for mode-division multiplexing and sensing in millimeter wave and sub-terahertz frequencies.
• Simultaneous use of multiple OAM modes in joint communication and sensing systems is challenging due to conflicting requirements: communication needs concurrent orthogonal modes for throughput, while sensing requires probing individual modes for location-dependent scattering signatures.

Purpose of the Study:

• To reconcile the conflicting requirements of communication and sensing in systems utilizing orbital angular momentum (OAM) beams.
• To develop a method for joint communication and sensing by flexibly reconfiguring OAM modes.

Main Methods:

• Exploiting the flexibility of OAM multiplexing to reconfigure subsets of OAM modes, generating diverse composite field distributions.
• Deriving theoretical limits for joint sensing performance.
• Validating the approach through extensive over-the-air experiments at 120 GHz.

Main Results:

• Demonstrated the ability to maintain orthogonality for data multiplexing while encoding rich spatial information through reflections from sensing targets.
• Achieved accurate target localization concurrently with high-speed data transmission.
• Validated the theoretical modeling and experimental design based on OAM beam physics and MIMO wireless propagation.

Conclusions:

• The proposed method effectively reconciles the demands of high-throughput communication and precise sensing using OAM multiplexing.
• This approach opens new possibilities for integrated communication and sensing systems in millimeter wave and sub-terahertz regimes.
• The findings highlight the potential of OAM beams for advanced wireless applications.