Fpga-implemented Real-Time DSP framework enabling experimental 50 m Photonics-Aided Millimeter-Wave links with enhanced frequency offset compensation

We experimentally demonstrate a 50 m wireless W-band photonics-aided transmission system with FPGA-implemented real-time DSP, achieving robust 7.3728 GBaud quadrature phase shift keying (QPSK) signal recovery. At the core of the digital signal processing (DSP) framework lies a novel frequency offset estimation algorithm, termed PF-CT-FOE, that integrates phase folding with cumulative phase transition feedback, resolving the accuracy-efficiency trade-off in large-frequency-offset compensation for real-time photonics-aided millimeter-wave systems. Building on this innovation, a parallelized real-time DSP framework is established specifically optimized for photonics-aided millimeter wave transmission. Through comprehensive numerical simulations, we characterized the performance of both the T/2-spaced constant modulus algorithm (T/2 CMA) and the proposed FOE algorithm, while all signal equalization and recovery components were fully implemented and validated on a field-programmable gate array (FPGA) platform. Implemented on 128-parallel FPGA paths, the system achieves real-time recovery of 7.3728 GBaud QPSK signals over 100 m fiber and 50 m wireless links with 1.2 × 10^-4 BER, below the 3.8 × 10^-3 threshold for HD-FEC. This work establishes a practical pathway for cost-sensitive millimeter-wave backhaul deployments requiring sub-ms latency.