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Modulation method and device suitable for asymmetric visible light communication

A visible light communication, asymmetric technology, applied in the field of visible light communication, can solve the problems of limiting the data transmission rate, unable to fully utilize the channel capacity data transmission rate, unable to improve the data transmission rate and other problems

Active Publication Date: 2021-01-05
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But LCD's low switching frequency (100-240Hz) fundamentally limits the data transfer rate
Moreover, the nonlinear problem of LCD will make the response time of modulation state switching highly asymmetrical, and even with a sufficiently high signal-to-noise ratio, the data transmission rate cannot be increased, that is, the channel capacity cannot be fully utilized to increase the data transmission rate.

Method used

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  • Modulation method and device suitable for asymmetric visible light communication
  • Modulation method and device suitable for asymmetric visible light communication
  • Modulation method and device suitable for asymmetric visible light communication

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Experimental program
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Embodiment 1

[0056] This embodiment discloses a modulation method suitable for asymmetric visible light communication. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation manners of other embodiments may be used as a supplement to this embodiment.

[0057] At present, based on the retroreflective visible light communication in the visible light communication system, it provides a low-power network connection solution for mobile networks and the Internet of Things. However, for low power consumption and long-term non-charging operation, a low-power liquid crystal modulator (Liquid Crystal Modulator, LCM) is basically used as the modulator 2 . But the response time of the liquid crystal modulator is slow, and its switching frequency (100-240 Hz) to change the state of the optical signal fundamentally limits the data transmission rate (hundreds of bps). Even by pushing up the symbol length limit, its data transfer rate does not exceed 1Kbps. Con...

Embodiment 2

[0062] This embodiment is a further improvement or supplement to Embodiment 1, and repeated content will not be repeated.

[0063] This embodiment also provides a modulation device suitable for asymmetric visible light communication, which includes at least a controller 1 and at least one modulator 2 . The controller 1 is configured to transmit a first symbol / first waveform within a first response time which is the fastest among the response times of the modulator 2 to change the state of the optical signal. Preferably, the controller 1 is configured to superimpose and / or interleave first symbols / first waveforms transmitted by different modulators 2 within their first response times. The first response time is the fastest response time of the modulator 2 when changing the state of the optical signal. Preferably, the second symbols / second waveforms are constructed by superimposing and / or interleaving first symbols / first waveforms emitted by different modulators 2 . Preferably...

Embodiment 3

[0065] This embodiment is a further improvement or supplement to Embodiments 1 and 2 and their combination, and the repeated content will not be repeated.

[0066] This embodiment also provides a modulation device suitable for asymmetric visible light communication, which includes at least a controller 1 and at least one modulator 2 . The controller 1 is configured to superimpose and / or interleave the first symbols / first waveforms emitted by the different modulators 2 during the fastest first response time among the response times to change the state of the optical signal to construct a second symbol / second waveform . Preferably, the controller 1 is configured to superimpose and / or interleave the first stages of different modulators 2 . The first stage is the stage corresponding to the first response time of the modulator 2 that changes the state of the optical signal fastest. For example, when the modulator 2 is a liquid crystal modulator, the first response time is the cha...

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Abstract

The present invention relates to a modulation method and device suitable for asymmetric visible light communication. The modulation device comprises at least a controller and at least one modulator, the controller being configured to construct a first symbol / first waveform representing information with a trend of the modulator to change an optical signal state. By means of the setting mode, the modulator can change the trend of the state of an optical signal, for example, the modulator rises, falls, falls to rise and the like to construct the first symbol / first waveform for modulation, modulation can be conducted without waiting for the modulator to completely finish state conversion of the modulator, and therefore the data transmission rate of communication is increased.

Description

technical field [0001] The invention belongs to the technical field of visible light communication, and relates to a modulation method and a device, in particular to a modulation method and a device suitable for asymmetric visible light communication. Background technique [0002] Visible Light Communication technology (Visible Light Communication, VLC) refers to the use of light in the visible light band as an information carrier, without the use of optical fiber and other wired channel transmission media, and a communication method that directly transmits optical signals in the air. Compared with traditional wireless communication equipment, the cost of visible light communication is low, and it is also more low-carbon and green. Natural advantages such as less interference, anti-eavesdropping, and large available bandwidth. The most common visible light communication technology uses light-emitting diodes (Light Emitting Diode, LED) as the basic unit of the signal source,...

Claims

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Application Information

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IPC IPC(8): H04B10/116H04B10/516
CPCH04B10/116H04B10/516
Inventor 许辰人吴越
Owner PEKING UNIV