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LED visible light communication system based on OFDM

A visible light communication and LED driving technology, applied in the field of visible light communication, can solve the problems of weak anti-interference ability and low communication rate of visible light communication system, and achieve the effect of improving anti-interference ability, expanding response bandwidth and flexible networking

Inactive Publication Date: 2015-11-18
HARBIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problems of low communication rate and weak anti-interference ability of the existing visible light communication system, thereby providing an OFDM-based LED visible light communication system

Method used

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  • LED visible light communication system based on OFDM

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specific Embodiment approach 1

[0013] Specific implementation mode one: combine figure 1 This embodiment is described in detail. The OFDM-based LED visible light communication system described in this embodiment includes: an amplifier circuit 1, an LED drive circuit 4, an LED array 5, and an optical filter 6. It also includes a pre-equalization circuit 2, an OFDM Modulation circuit 3, photoelectric module 7 and signal processing module 11;

[0014] The input end of the amplifier circuit 1 is connected to the output end of the signal source, the output end of the amplifier circuit 1 is connected to the communication signal input end of the OFDM modulation circuit 3, the output end of the pre-equalization circuit 2 is connected to the compensation signal input end of the OFDM modulation circuit 3, and the OFDM modulation The output end of the circuit 3 is connected to the input end of the LED driving circuit 4, the output end of the LED driving circuit 4 is connected to the input end of the LED array 5, the o...

specific Embodiment approach 2

[0016] Specific embodiment 2: This embodiment is a further description of the OFDM-based LED visible light communication system described in specific embodiment 1. In this embodiment, the above-mentioned photoelectric module 7 includes a PIN photodetector 8, a preamplifier circuit 9 and low pass filter 10;

[0017] PIN photodetector 8 receives light beam, and the output end of PIN photodetector 8 connects the input end of preamplifier circuit 9, and the output end of preamplifier circuit 9 connects the input end of low-pass filter 10, and the input end of low-pass filter 10 The output end serves as the output end of the photoelectric module 7 .

specific Embodiment approach 3

[0018] Specific Embodiment 3: This embodiment is a further description of the OFDM-based LED visible light communication system described in Specific Embodiment 1. In this embodiment, the signal processing module 11 includes an OFDM demodulation circuit 12, a DSP 13 and a post-equalization circuit. 14;

[0019] The input end of OFDM demodulation circuit 12 and the communication signal input end of DSP13 are all used as the input end of signal processing module 11, and the output end of OFDM demodulation circuit 12 is connected with the demodulation signal input end of DSP13, and the obvious characteristic signal output end of DSP13 is connected The input end of the post equalization circuit 14 and the output end of the post equalization circuit 14 are connected to the compensation signal input end of the DSP 13 , and the communication signal output end of the DSP 13 is used as the output end of the signal processing module 11 .

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Abstract

An LED visible light communication system based on OFDM relates to a visible light communication technology. The LED visible light communication system of the invention is used for solving the problem that transmission speed rate is low and the anti-jamming capability is weak because the visible light communication system is simple in design. A pre-equalizing circuit is used for compensating distortion brought by a system via a device and a channel so as to extend a response bandwidth of an LED array, and an OFDM modulator circuit takes full advantage of existing bandwidth to improve transmission rate. A photoelectric module is used for converting the received optical signal into an electric signal; a signal processing circuit is used for obtaining an obvious characteristic signal after processing the input electric signal. A communication protocol is used for solving the problems of a transmitting and receiving acknowledgement mechanism, a message read-write mechanism, a time sequence matching mechanism. By using an OFDM modulation technique as basis, and using DSP digital information processing technique as core, the LED visible light communication system of the invention improves the transmission speed rate. The pre-equalizing circuit and a post-equalizing circuit improve the anti-jamming capability of the system. The LED visible light communication system of the invention could be applied to visible light communication of an LED.

Description

technical field [0001] The invention relates to visible light communication technology. Background technique [0002] The maturity and wide application of LED lighting technology have brought new opportunities for the development of visible light communication. With its high modulation rate, low energy consumption under working conditions, and easy control of the central wavelength, white LEDs can achieve deep coupling between lighting and communication. LiFi technology, which uses white light LED as the communication medium, has become another new application field of wireless short-range communication due to its advantages such as wide spectrum range, low communication power consumption, low electromagnetic interference, and strong privacy. [0003] Existing visible light communication systems usually use on-off keying modulation or pulse width modulation. Due to the simple system design, the communication rate is low and the anti-interference ability is weak. Contents ...

Claims

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Application Information

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IPC IPC(8): H04B10/116H04L27/26
Inventor 王宏民王中杰薛萍刘贞周李冰
Owner HARBIN UNIV OF SCI & TECH
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