Balancing noise and nonlinear distortion by power loading in FBMC OWC

Area of Science:

• Optical Wireless Communications
• Signal Processing
• LED Technology

Background:

• Nonlinear distortion (ND) is a major limitation in LED-based optical wireless communication systems, especially with multicarrier modulation.
• Existing mitigation techniques like power back-off or complex equalizers increase computational load.
• Efficiently managing ND is crucial for achieving higher data rates.

Purpose of the Study:

• To demonstrate a method for mitigating nonlinear distortion in multicarrier optical wireless communications without added computational cost.
• To introduce and evaluate a novel adaptive nonlinear power loading (NPL) algorithm.
• To improve asymptotic information rates in systems utilizing offset quadrature amplitude modulated filter bank multicarrier.

Main Methods:

• Theoretical analysis using a nonlinear LED behavioral model.
• Experimental validation of subcarrier power loading combined with bit or entropy loading.
• Comparison of uniform power loading, pre-emphasis, and the proposed NPL algorithm.

Main Results:

• The proposed NPL algorithm effectively suppresses ND, outperforming uniform loading and pre-emphasis at intermediate power levels.
• Combining NPL with entropy loading (EL) achieved an 11% improvement in asymptotic information rates over conventional EL.
• A 17% gain was observed compared to the Levin-Campello algorithm.

Conclusions:

• Subcarrier power loading combined with bit or entropy loading is an effective strategy to mitigate ND in multicarrier optical wireless systems.
• The adaptive NPL algorithm offers superior performance for ND mitigation without increasing computational complexity.
• This approach enables higher data rates in optical wireless communication systems.