Dual-chirp-based photonic THz-ISAC system with adaptive frequency synchronization

Area of Science:

• Photonics
• Terahertz (THz) technology
• Integrated sensing and communication (ISAC) systems

Background:

• Photonic THz-ISAC systems are gaining prominence for combined sensing and communication.
• Frequency offset (FO) poses a challenge for synchronization in these systems.
• Existing methods often require training preambles, increasing overhead.

Purpose of the Study:

• To develop an adaptive FO compensation method for dual-chirp ISAC waveforms.
• To enable preamble-free frequency synchronization.
• To enhance robustness against system noise.

Main Methods:

• Utilizing the fractional Fourier transform (FrFT) for FO estimation.
• Implementing an adaptive compensation scheme for dual-chirp waveforms.
• Experimental validation in a 300 GHz photonic THz-ISAC system.

Main Results:

• Successful compensation of frequency offsets from -5 to 5 GHz.
• Achieved estimation error below 0.08%.
• Demonstrated low chirp-pilot power overhead of 0.5%.

Conclusions:

• The proposed FrFT-based method effectively compensates frequency offsets in photonic THz-ISAC systems.
• Preamble-free synchronization is achievable with high accuracy and noise robustness.
• The technique supports high-speed data transmission (20 Gbps QPSK) and precise sensing (1.5 cm resolution).