An Energy-Efficient FPGA-Based Real-Time IMDD OFDM-PON Enabled by an Efficient FFT.

Area of Science:

• Optical Communications
• Digital Signal Processing
• Integrated Circuit Design

Background:

• Passive Optical Networks (PONs) are crucial for broadband access.
• Intensity Modulation Direct Detection (IMDD) is a cost-effective modulation technique for PONs.
• Orthogonal Frequency Division Multiplexing (OFDM) enhances spectral efficiency in optical systems.

Purpose of the Study:

• To propose and implement a highly energy-efficient 32-parallel 64-point FFT scheme for IMDD OFDM-PON.
• To establish a relationship between FFT power consumption and FPGA logic resource utilization.
• To optimize FFT bit resolution for minimal power consumption under varying received optical power levels.

Main Methods:

• Implementation of a 32-parallel 64-point FFT on a Xilinx ML605 FPGA platform.
• Experimental verification of an FPGA logic resource power consumption model for FFT calculations.
• Derivation of a resource selection principle for FFT bit resolution optimization.

Main Results:

• Established a clear relationship between FFT power consumption and FPGA logic resource usage.
• Achieved a 76.1% reduction in FFT power consumption compared to traditional Spiral FFT at -21 dBm received optical power.
• Demonstrated up to 43% power saving in real-time IMDD OFDM-PON receivers using the proposed FFT scheme.

Conclusions:

• The proposed energy-efficient FFT scheme significantly reduces power consumption in IMDD OFDM-PON systems.
• The derived resource selection principle enables power optimization through FFT bit resolution adjustment.
• This work offers a practical solution for reducing the operational cost of next-generation optical access networks.