Visible Light Communication Receiver Sampling Frequency Reduction
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Solution Overview
Problem
In visible light communication systems, a high sampling frequency is required for symbol clock synchronization, which can limit the number of pixels and reduce the throughput, making it challenging to maintain accurate synchronization while receiving signals from multiple transmitters.
Innovation Solution
A receiver is designed with a received signal generating unit that measures the intensity of electrical signals at a predetermined interval to generate a sequence of received signals, and a parameter estimation unit that estimates parameters such as maximum luminance, synchronization shift, and steady noise level, allowing for reduced sampling frequency and independent synchronization with each transmitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high sampling frequency is used for symbol clock synchronization, then synchronization accuracy is improved, but the number of pixels must be reduced and throughput decreases
Solution Approach 1:
The patent changes the parameter of sampling frequency from high to low, and introduces a new parameter (distribution of received signals) to maintain synchronization accuracy. By estimating parameters like maximum luminance value, synchronization shift, and steady noise level from the signal distribution, the system achieves accurate symbol timing recovery without requiring high sampling frequency, thus maintaining both synchronization accuracy and throughput
2Measurement precision
If a high sampling frequency is used for symbol clock synchronization, then synchronization accuracy is improved, but the number of pixels must be reduced
Solution Approach 1:
The patent changes the sampling frequency parameter from high to low, and compensates by using distribution-based parameter estimation. This allows the system to maintain synchronization accuracy while preserving a larger number of pixels, as the estimation method does not depend on high sampling rates
3Productivity
If the sampling frequency is reduced, then throughput is improved and more pixels can be used, but symbol timing recovery becomes less accurate
Solution Approach 1:
The patent uses feedback by continuously estimating the distribution of received signals and adjusting parameter estimates (maximum luminance value, synchronization shift, steady noise level) based on the observed signal distribution. This feedback mechanism enables accurate symbol timing recovery even at lower sampling frequencies, maintaining both throughput and accuracy
Solution Approach 2:
The patent introduces new parameters for estimation (distribution-based parameters) to compensate for the reduced sampling frequency. By estimating synchronization shift and other parameters from the signal distribution rather than relying on high-frequency sampling, the system maintains timing recovery accuracy while operating at lower sampling rates that support higher throughput
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the required sampling frequency for symbol timing recovery, enabling more efficient data transmission and supporting multiple transmitters without reducing the number of pixels or increasing the flashing period.
Implementation Method 1
a photodetector or an image sensor that is an array of photodetectors is used as a light receiving element of a receiver
Data Source
AI summary
A sampling frequency required for symbol timing recovery is made smaller than that of the related art. A receiver 1 performs visible light communication with a transmitter 8. A received signal generating unit 112 measures an intensity of an electrical signal corresponding to an optical signal received from a transmitter 8 at a predetermined time interval to generate a sequence of received signals. A parameter estimation unit 12 uses a distribution of received signals estimated from the sequence of received signals to estimate any one or more parameters of a maximum luminance value, a synchronization shift, and a steady noise level, the one or more parameters including at least the maximum luminance value.