W-Band Wireless Prototype: Advancing Quantum-Resistant Communications  

The SMARTY Project is progressing toward a secure, high-speed, short-range wireless link through the development of a W-band prototype (75–110 GHz). This forms a key component of a quantum-resistant transceiver tailored for edge environments where secure communication is required but wired infrastructure is not available. 

W-Band Prototype: Current Status 

The initial laboratory setup has demonstrated a unidirectional uplink (UL) over a wireless W-band path, while the downlink (DL) remains fiber-based. 

Transmitter architecture includes: 

  • Coherent detection at the fiber input 
  • A Uni-Traveling Carrier Photodiode (UTC-PD) generating the W-band signal by optical heterodyning 
  • A Medium Power Amplifier (MPA) and horn antenna for RF transmission 

Receiver chain includes: 

  • A horn antenna and Low Noise Amplifier (LNA) 
  • An Envelope Detector (ED) for amplitude demodulation 
  • A Mach-Zehnder Modulator (MZM) to convert the received signal back to the optical domain 

Tests with a 1.3 Gbps On-Off Keying (OOK) signal over 80 GHz show promising signal integrity, with clean eye diagrams at the output of the envelope detector. Current link distance is ~0.5 meters, limited by the absence of the LNA in the downlink. 

Next Steps 

  1. Bidirectional Wireless Communication: 
    The system will be upgraded to support full bidirectional transmission. This will be achieved via frequency multiplexing, a method commonly used in mobile and optical networks. 
    • Uplink: 75–92 GHz 
    • Downlink: 93–110 GHz
  1. Antenna Architecture: 
    Two configurations are under evaluation: 
    • Four-antenna setup (two per direction) 
    • Two-antenna setup using circulators to handle simultaneous TX/RX, with attention to minimizing coupling between transmitter and receiver paths 
  1. Encryption and Modulation Enhancements: 
    • Integration of AES-256 encryption for secure communication
    • Investigation of phase modulation schemes (e.g., QPSK), contingent on implementing a laser phase-locking mechanism 
  1. Extended Range: 
    • LNA integration and improved antenna modules will support distances of 5–10 meters, aligning with target use cases such as field-deployed edge devices. 

    This prototype lays the foundation for quantum-resilient wireless links applicable to smart mobility, defense, and secure IoT deployments. 

    📡 To follow progress and explore technical deliverables, visit: 
    https://www.smarty-project.eu 

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