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CDMA modulation based 3D positioning method of visible light communication (VLC)

A technology for visible light communication and three-dimensional positioning, applied in the field of three-dimensional positioning of visible light communication based on CDMA modulation, can solve the problems of strong volatility, limit positioning accuracy, increase system complexity, etc., achieve speed and quality improvement, overcome positioning errors, realize The effect of code division multiplexing

Active Publication Date: 2017-03-08
SOUTH CHINA UNIV OF TECH
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Problems solved by technology

However, these positioning systems have the following disadvantages: (i) more signal access points need to be reconfigured, which increases the cost of the indoor positioning system and the difficulty of control; (ii) due to the uneven spatial distribution of wireless signals and the stability It is not high, and the fluctuation of the positioning point at the same point is strong, which limits the accuracy of positioning; (iii) These wireless positioning technologies will generate electromagnetic interference. On the one hand, they will be affected by other wireless services and affect the quality of positioning , on the other hand, it is not suitable for electromagnetic sensitive occasions such as hospitals and airports
Further, when triangulation algorithm is generally used to estimate the positioning distance based on received signal strength based on Intensity Modulation and Direct Detection (IM / DD), it is necessary to know the position coordinates of at least three different reference points, and The ID position information sent by different reference point sources generally overlap in the time domain and frequency domain, and intersymbol interference will occur due to multipath effects, which greatly limits the accuracy of VLC positioning
In order to overcome inter-symbol interference and further improve positioning accuracy, Kim Hyun-Seung et al. used carrier allocation technology, but since the transmitter and receiver do not change stably with frequency, an additional compensation algorithm is required; Yang Se-Hoon et al. respectively use time slot Allocation technology and wavelength allocation technology to overcome the influence of intersymbol interference, but requires strict synchronization between the transmitter and receiver and requires optical filters or multiple receivers for diversity reception; these methods greatly increase the complexity of the system

Method used

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  • CDMA modulation based 3D positioning method of visible light communication (VLC)
  • CDMA modulation based 3D positioning method of visible light communication (VLC)
  • CDMA modulation based 3D positioning method of visible light communication (VLC)

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Embodiment 1

[0052] Such as figure 1 As shown in the figure, it is a schematic diagram of a system for realizing indoor visible light communication positioning based on the RSS three-dimensional positioning algorithm based on CDMA modulation. In this embodiment, four LED lamps are set at the four endpoints of the ceiling of the system space model of L*W*H (unit: m) as a positioning unit, such as figure 1 LED A, LED B, LED C, LED D shown. On the horizontal plane from the ground h, three identical photodiodes are respectively located at the three corners of an equilateral triangle with a side length of 0.01m to form a photodetection device.

[0053] Further, as figure 2 In the schematic block diagram of the system shown, the ID position information of the three LED lamps is baseband modulated by the OOK baseband modulation module to form a baseband modulation signal; the baseband modulation signal is formed after the spread spectrum operation of the CDMA spread spectrum module. frequency...

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Abstract

The invention discloses a CDMA modulation based 3D positioning method of VLC. Multiple reference point light sources exist in a traditional visible light indoor positioning system, intersymbol interference is caused among the reference point light sources due to different transmission paths, and the precision of indoor positioning is influenced greatly. Optical signals which are overlapped in both time domain and frequency domain originally can be separated by utilizing orthogonality of spread spectrum coding. A positioning position area is determined according to ID position information obtained by a positioning terminal, and the coordinate of a positioning position is determined according to a light intensity attenuation factor of a reception end by utilizing an RSS triangular positioning algorithm. Compared with the traditional VLC positioning technology, the positioning precision is improved, the system is simple and stable and does not need synchronous emission, and the system has a wide application prospect.

Description

technical field [0001] The invention relates to a visible light communication positioning technology, in particular to a CDMA modulation-based visible light communication three-dimensional positioning method. Background technique [0002] In recent years, Indoor Positioning Systems (IPS) has become the hottest topic. This technology is beneficial to indoor services for humans and intelligent robots, and can provide users with location information and push corresponding service information. Global Positioning System (Global Positioning System, GPS) is a good navigation system for outdoor applications, and has a wide range of applications in mobile phone map services, car navigation, ships and aircraft. However, due to multipath fading, electromagnetic shielding effects, and interference from other wireless devices, traditional outdoor positioning technologies such as GPS have poor signal coverage indoors, and there are large positioning errors when used for indoor positioning...

Claims

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Application Information

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IPC IPC(8): G01S5/16H04B10/116
CPCH04B10/116G01S5/16Y02D30/70
Inventor 吴玉香关伟鹏易佳霖陈颖聪文尚胜
Owner SOUTH CHINA UNIV OF TECH
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