Theoretical probability distribution model and reduction techniques based on an interleaved DFT spread for PAPR in a...

Area of Science:

• Optical Communications
• Signal Processing
• Information Theory

Background:

• Peak-to-Average Power Ratio (PAPR) is a critical parameter in Digital Sub-Carrier Multiplexing (DSCM) systems, impacting power efficiency and performance.
• Existing literature lacks a theoretical probability distribution model for PAPR in DSCM systems.
• High PAPR can degrade the bit error rate (BER) performance in optical fiber communication systems.

Purpose of the Study:

• To propose a novel theoretical probability distribution model for PAPR in DSCM systems.
• To introduce an Interleaved Discrete Fourier Transform Spread DSCM (I-DFT-S-DSCM) scheme for PAPR reduction.
• To evaluate the effectiveness of the proposed model and scheme in a 64-GBaud 16-QAM DSCM system.

Main Methods:

• Development of a theoretical PAPR probability distribution model for DSCM.
• Implementation of an I-DFT-S-DSCM scheme introducing reversible correlations between subcarriers.
• Experimental validation using a 64-GBaud 16-QAM DSCM system with varying subcarrier counts (4, 8, 16).
• Transmission tests over 100-km standard single-mode fiber (SSMF) to assess BER performance.

Main Results:

• The proposed PAPR model achieved Mean Squared Errors (MSE) below 10^-5 for Complementary Cumulative Distribution Functions (CCDF) in both DSCM and I-DFT-S-DSCM.
• The I-DFT-S-DSCM scheme reduced PAPR by up to 1.44 dB compared to conventional DSCM.
• In 100-km SSMF transmission, I-DFT-S-DSCM achieved ~1.1 dB PAPR reduction and improved receiver sensitivity by ~0.7 dB at a 7% HD-FEC threshold.

Conclusions:

• The developed theoretical model accurately characterizes PAPR in DSCM and I-DFT-S-DSCM systems.
• The I-DFT-S-DSCM scheme offers a viable solution for significant PAPR reduction in high-speed optical communication systems.
• The proposed scheme enhances overall system performance, including receiver sensitivity, crucial for long-haul fiber transmissions.