Comparison of interpolation-based sampling frequency offset compensation schemes for practical OFDM-VLC systems
Optics Express
|March 4, 2020
Summary
This study demonstrates real-time compensation for sampling frequency offset in visible light communication (VLC) systems using digital interpolation filters. The research evaluates performance and complexity trade-offs for cost-sensitive applications.
Area of Science:
- Electrical Engineering
- Optical Communications
- Signal Processing
Background:
- Sampling frequency offset (SFO) poses a challenge in Orthogonal Frequency-Division Multiplexing (OFDM)-based Visible Light Communication (VLC) systems, particularly with low-cost converters.
- Oversampling at the receiver is necessary to counteract aliasing caused by imperfect digital-to-analog converters (DACs) and nonlinearities in visible light sources.
Purpose of the Study:
- To experimentally evaluate the feasibility of digital interpolation-based SFO compensation schemes for cost-sensitive OFDM-VLC applications.
- To compare the transmission performance and digital signal processing (DSP) complexity of different order interpolation filters (2nd, 3rd, and 4th) in a real-time OFDM-VLC receiver.
Main Methods:
- A real-time OFDM-VLC receiver was implemented incorporating 2nd, 3rd, and 4th order digital interpolation filters.
- An OFDM frame structure was designed for synchronization, including SFO estimation and compensation, considering DSP precision and latency.
- Experimental demonstrations were conducted to assess the effectiveness of the implemented SFO compensation schemes.
Main Results:
- The study successfully demonstrated real-time SFO compensation in an OFDM-VLC system using digital interpolation filters.
- Performance and DSP complexity were compared across different filter orders, providing insights into their suitability for various VLC applications.
- The designed OFDM frame structure facilitated effective synchronization, including SFO estimation and compensation.
Conclusions:
- Digital interpolation filters offer a viable solution for SFO compensation in cost-sensitive OFDM-VLC systems.
- The choice of interpolation filter order impacts both transmission performance and DSP complexity, requiring careful consideration for specific applications.
- The experimental validation confirms the practical applicability of these SFO compensation techniques in real-time VLC systems.
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