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Data transmission method and device based on retro-reflection visible light communication

A data transmission method and a technology of a data transmission device, which are applied in digital transmission systems, transmission systems, free space transmission, etc., and can solve problems such as "spectrum compression, complex medium access control, and intersymbol interference"

Active Publication Date: 2020-12-01
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the large-scale deployment of such tags may introduce complex medium access control and interference management issues, and may even exacerbate the problem of "spectrum crunch" in unlicensed frequency bands
"Spectrum crunch" problem: very low spectral efficiency due to packet collisions, carrier sensing, interference, retransmissions, etc.
However, the technical solution disclosed in this document has an excessively long symbol length due to the multi-ary modulation method used, which increases the difficulty and complexity of system modulation and demodulation, and also has serious intersymbol interference problems

Method used

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  • Data transmission method and device based on retro-reflection visible light communication
  • Data transmission method and device based on retro-reflection visible light communication
  • Data transmission method and device based on retro-reflection visible light communication

Examples

Experimental program
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Effect test

Embodiment 1

[0069] Based retroreflective visible light communication, a light tag 1 requires the ability modulated optical signal, based on the economic cost considerations in practical applications, it is desirable modulation and demodulation scheme in a simple label side of the light, to avoid the cost and power consumption increase, thereby facilitating mobility, to enhance the deployment of a side of the optical labels, but also conducive to miniaturization of a light tag and no long-term battery operation. OOK modulation scheme is simple, does not require additional costs modulation, applied to an end of the natural retroreflected light signal visible light communication. Thus, the tag 1 using the light modulating LCD. LCD may pass or block light under control of the electric field. The principle is a polarizer LCD device is provided by two parallel and a liquid crystal material sandwiched between two polarizing device configuration. Molecules of the liquid crystal material distorted ali...

Embodiment 2

[0097] This example discloses a data transmission device based on reverse reflection visible light communication, and the overall and / or portion of the preferred embodiment of the other embodiments may be supplemented as the supplement of the present embodiment.

[0098] In reverse reflection visible communication, the light tag 1 can modulate information, for example, modulation can be made by micro-electro-mechanical system, MEMS or Semiconductor Multi-quantum Well (MQW) technology. However, in practical applications, based on economic cost reasons, it is desirable to use existing inverse reflective materials to achieve reverse reflection modulation, such as reverse reflective fabrics, which are characterized by thin, flexibility and low cost. Therefore, the light label 1 is modulated using an LCD in order to modulate light reflected by such a fabric. The LCD can pass or block light under the control of the electric field, and the principle is that the LCD is composed of two p...

Embodiment 3

[0112] The present invention also provides a data transmission terminal based on reverse reflection visible light, at least a light tag 1. The light tag 1 reverse reflects the optical signal transmitted by the reader 2 and blocks or modulates the optical signal by the light modulation unit 14. In the case where the light modulation unit 14 cannot immediately switch on the first state of the barrier optical signal and the second state of the optical signal, the optical tag 1 is configured to be based on the optical modulation unit 14 based on the optical modulation unit 14 due to the first state of the barrier optical signal and the second state of the optical signal. The first state and the tendency of the light signal brightness between the second state are modulated. The light tag 1 is configured to:

[0113] Use two different symbols when modulating the first class information in the original message, and the first symbol is the same as the previous symbol;

[0114] Use the sam...

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Abstract

The invention relates to a data transmission method and device based on retro-reflection visible light communication. The method comprises the following steps: the optical label retroreflects an optical signal sent by the reader-writer and modulates the optical signal through the optical modulation unit in a mode of blocking the optical signal or modulating the optical signal through the optical signal. The optical modulation unit cannot be immediately switched between a first state of blocking an optical signal and a second state of passing through the optical signal due to nonlinear responsetime. The optical label is modulated based on a trend of a change in brightness of an optical signal between a first state and a second state of the optical modulation unit. Through the setting mode,the signal can be modulated without waiting until the light modulation unit completely enters the first state and the second state, and the limitation of the response time of the light modulation unit is broken through.

Description

Technical field [0001] The present invention belongs to the field of wireless data transmission, and more particularly to data transmission methods and apparatus based on reverse reflection visible communication. Background technique [0002] It is expected that the Internet will consist of 50 billion devices, which will cause the Internet-of-Thing, IoT design. The Magnificent Vision of the Internet of Things - bring everything to the Internet so that you can better perceive, understand and drive the real world, that is, the foundation should be able to connect each object to the Internet and achieve data exchange that has never been seen. . In fact, most new generations, whether it is a household appliance from the outside, a mobile device with a large volumetric battery, or a micro-implantable sensor and a thin wearable device, claims to have "Internet of Things Capacity". However, it is necessary to fully realize the vision of the Internet of Things, but also need to deploy mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/116H04B10/54H04L1/00
CPCH04B10/116H04B10/541H04L1/0054
Inventor 许辰人沈国斌徐燮阳沈洋陈国俊王璞瑞吴越
Owner PEKING UNIV