Photonic Millimeter-Wave Joint Radar Communication System Using Spectrum-Spreading Phase-Coding

A novel millimeter-Wave (mm-Wave) joint radar and communication (JRC) system based on photonic spectrum-spreading phase-coding is proposed. The key to the proposed system is the convergence of photonic microwave phase-coding and spectrum-spreading multiplexing techniques. Phase-coding enables the generation of wideband mm-Wave JRC signal, leading to both high range resolution (< 3.5 cm) for radar detection and high capacity (>1 Gb/s) for wireless communication. The spectrum-spreading multiplexing orthogonalizes the radar signal and communication data, highly reducing mutual interferences. In addition, the spectrum-spreading multiplexing is able to improve both peak sidelobe ratio (PSR) for radar and anti-jamming/anti-noise performance for communication. In the proof-of-concept experiments, a JRC phase-coding signal at 35 GHz is generated. For a 5-Gb/s coding rate, the signal-to-noise ratio (SNR) margin is improved by around 13.8 dB for wireless communication below the pre-forward error correction (FEC) limit, while the PSR reaches ~12 dB for radar. Moreover, the impact of spreading gain on the communication capacity has been discussed, revealing that an optimized spreading gain should be set to balance the radar and communication performances.