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Modulation and demodulation method for visible light communication

A visible light communication, modulation and demodulation technology, applied in multiplex communication, electromagnetic wave transmission system, short-range system, etc., can solve the problems of complex structure and signal interference, achieve simple implementation, improve transmission rate and frequency spectrum The effect of utilization

Inactive Publication Date: 2021-05-07
DONGGUAN POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is interference between various types of signals, and the structure is complex

Method used

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  • Modulation and demodulation method for visible light communication
  • Modulation and demodulation method for visible light communication
  • Modulation and demodulation method for visible light communication

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] The present invention proposes a virtual and real polarity separation OFDM (RIPSO-OFDM) visible light modulation and demodulation technology, such as figure 1 As shown, compared with the existing mainstream DCO-OFDM, ACO-OFDM, PSO-OFDM and other algorithms, its characteristic is that a complex OFDM signal is decomposed into four The "real" and "positive" signal of the positive value of the part and the negative value of the imaginary part, and then use the characteristics of linear superposition and coupling of visible light in free space to greatly improve the transmission rate and spectrum utilization. Its system principle is as figure 2 shown.

[0064] The input data is a binary information sequence, and after serial to parallel conversion (Serial to Parallel, S / P), quadrature amplitude modulation (Quadrature Amplitude Modulation, QAM) is performed to obtain a complex array S, as shown in formula (1).

[0065] S=[S 1 ,S 2 ,...,S N ] (1)

[0066] where N is the...

Embodiment 2

[0090] More specifically, on the basis of Embodiment 1, the present invention is compared with existing algorithms in terms of ideal transmission rate and ideal spectrum utilization.

[0091] Let the CP length of OFDM symbol be NCP, then the ideal transmission rate R of RIPSO-OFDM technology RIPSO As shown in formula (14).

[0092]

[0093] Among them, N is the number of subcarriers, B is the modulation bandwidth, and M is the modulation order of QAM. From this, the ideal spectrum utilization rate E of the RIPSO-OFDM scheme can be obtained RIPSO , as shown in formula (15).

[0094]

[0095] According to their respective generation mechanisms, the ideal transmission rate and ideal spectrum utilization rate of DCO-OFDM, ACO-OFDM, PSO-OFDM, GLIM-OFDM and other technologies can be obtained, such as equations (16), (17), (18), ( 19), (20), (21), (22) and (23).

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Comparin...

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Abstract

The invention provides a modulation and demodulation method for visible light communication, which comprises the following steps of: processing four groups of time domain signals including a real part positive value signal, an imaginary part positive value signal, a real part negative value signal and an imaginary part negative value signal by using a to-be-sent information sequence, respectively carrying out digital-to-analog conversion on the four groups of time domain signals, modulating the four groups of time domain signals into corresponding optical signals, and transmitting the corresponding optical signals in a visible light channel; and finally, enabling the receiving end to receive and restore the signal, and restoring the to-be-sent information sequence from the optical signal. According to the modulation and demodulation method for visible light communication provided by the invention, a complex OFDM signal is decomposed into four real and positive signals with information of a real part positive value, a real part negative value, an imaginary part positive value and an imaginary part negative value respectively, and then linear superposition and coupling characteristics of visible light in a free space are utilized; and the transmission rate and the spectrum utilization rate are greatly improved, the implementation mode is simple, and the method can be applied to various high-speed visible light communication systems.

Description

technical field [0001] The present invention relates to the technical field of optical communication, and more specifically, to a modulation and demodulation method for visible light communication. Background technique [0002] Visible light communication uses light-emitting diodes (Light-Emitting Diode, LED) to send out high-speed bright and dark flashing signals for communication. It has the advantages of high transmission data rate, no radiation, no authorization for spectrum use, and strong confidentiality. It forms a complementary advantage with radio frequency communication. Modulation and demodulation is a key technology and research hotspot of Visible Light Communication (VLC). Restricted by the physical characteristics of LEDs, the VLC system uses "Intensity Modulation / Direct Detection (IM / DD)" as its modulation and demodulation In the way of modulation, IM / DD realizes light intensity modulation, which requires the value of the electrical signal to be "real" and "po...

Claims

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Application Information

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IPC IPC(8): H04B10/116H04B10/516H04J11/00
CPCH04B10/116H04B10/516H04J11/00
Inventor 杨恺卞建勇麦强赵美玲杨润丰
Owner DONGGUAN POLYTECHNIC
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