Flicker suppression method in OFDM modulation mode in visible light communication

A technology of visible light communication and modulation mode, which is applied in the field of visible light communication to achieve the effect of ensuring healthy lighting, avoiding discomfort to human eyes, and facilitating implementation and promotion.

Pending Publication Date: 2022-07-12
NANJING UNIV OF POSTS & TELECOMM
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  • Abstract
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  • Application Information

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Problems solved by technology

This design method mainly aims at the potential health effects caused by low-frequency flicker in indoor visib

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  • Flicker suppression method in OFDM modulation mode in visible light communication
  • Flicker suppression method in OFDM modulation mode in visible light communication

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[0020] The objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of the preferred embodiments. These embodiments are only typical examples of applying the technical solutions of the present invention, and all technical solutions formed by taking equivalent replacements or equivalent transformations fall within the scope of protection of the present invention.

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] like figure 1 As shown, the specific implementation steps of the present invention are as follows:

[0023] Step 1. Randomly generate a binary bit sequence, and then perform quadrature amplitude modulation QAM after serial-parallel conversion;

[0024] Step 2. The QAM modulated signals obtained in step 1 correspond to the frequency domain sub-carriers of OFDM, and the sub-carriers are sort...

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Abstract

The invention discloses a flicker suppression method under an OFDM (Orthogonal Frequency Division Multiplexing) modulation mode in visible light communication. The problem of eye health caused by low-frequency flicker when a white light LED (Light Emitting Diode) is used as a transmitter in an existing indoor VLC (Visible Light Communication) system is effectively relieved. According to the method, OFDM frequency domain subcarriers of a sending end are arranged, after the first subcarrier and the (N-1) th subcarrier containing low-frequency flicker components are selected to be subjected to zero setting operation, Ermitt symmetry and IFFT are conducted on subcarrier sequences, and finally time domain OFDM signals are loaded to a white light LED to be sent to a channel to be transmitted after being subjected to unipolarity processing. The design is different from a traditional flicker suppression method, and low-frequency flicker components are removed by analyzing and processing the signals of the frequency domain at the transmitting end. The subcarrier containing the low-frequency flicker component does not carry data after zero setting, and the visible light signal transmitted in the channel does not contain the low-frequency component below 200Hz, so that the discomfort of human eyes caused by low-frequency flicker in the VLC system is effectively avoided while the communication function is ensured and the normal indoor illumination is maintained.

Description

technical field [0001] The invention belongs to the technical field of visible light communication, and is especially suitable for a data transmission mode in an indoor visible light model in which LEDs simultaneously realize lighting and communication functions. Background technique [0002] Visible Light Communication (VLC) is an optical wireless communication technology that uses visible light in the wavelength range of 380nm to 780nm as a modulated carrier for information transmission. Light Emitting Diode LED is a two-lead semiconductor light source that converts electrical signals into optical signals, and can be used as transmitters in visible light communication systems. White LED-based visible light communication provides a spectrum-free, ultra-high-speed, reliable, safe, and easy-to-interconnect solution for indoor wireless communication. When indoor communication base stations are combined with white LED lighting fixtures and connected to other communication netwo...

Claims

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Application Information

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IPC IPC(8): H04L27/26H04B10/50H04B10/116
CPCH04L27/2634H04B10/116H04B10/502Y02D30/70
Inventor 陈健钟倩雯
Owner NANJING UNIV OF POSTS & TELECOMM
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