CN205986877U - It is thus clear that optical locating hardware systems based on CDMARF fuses communication - Google Patents

Abstract

The utility model discloses an it is thus clear that optical locating hardware systems based on CDMARF fuses communication, including modulation module, emission module, transport module, receiving module and demodulation module, the modulation module is used for realizing QPSK modulation, the modulation of OOK baseband and CDMA spread spectrum, emission module includes LED drive circuit, LED lamps and lanterns and emit antenna, transport module includes optical channel and radio frequency channel among the free space, receiving module includes photodetecting device, radio signal recepition machine, adaptive filtering circuit and amplifier circuit, demodulation module is used for realizing that OOK demodulation, QPSK separate the despreading of mediation CDMA. The utility model discloses not only improve the precision of location far away, has not needed to launch in step the signal moreover, the utility model discloses system simple structure has improved the robustness of system greatly, has wide market prospect and application space.

Description

A visible light positioning hardware system based on CDMA/RF fusion communication

technical field

The utility model relates to a visible light positioning method, in particular to a visible light positioning hardware system based on CDMA/RF fusion communication.

Background technique

With the improvement of people's living standards and the continuous development of economy and technology, people's demand for navigation and positioning services is increasing day by day. The Global Positioning System (GPS) has wide coverage, high positioning accuracy, complete functions, and mature technology. However, because the signals emitted by GPS satellites cannot effectively penetrate buildings, it cannot perform accurate positioning in many indoor environments.

In recent years, visible light communication technology has attracted the attention of many experts and scholars at home and abroad. VLC has been involved in many fields and has made some progress, such as the proposal of LiFi. The possible application prospects of visible light communication include indoor short-range wireless access, indoor positioning, intelligent transportation network in urban environment, and so on. If visible light communication technology is applied to positioning, it has many advantages compared with traditional positioning technology, such as no electromagnetic interference, fewer additional modules, high positioning accuracy, good confidentiality, and consideration of communication and lighting. This makes the visible light localization method widely valued.

However, optical channels are susceptible to interference from weather conditions and ambient light, and optical links are interrupted when obstacles appear. Moreover, due to the existence of multipath effects and inter-symbol interference of different LED lamps, the positioning accuracy is greatly reduced.

Utility model content

In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this utility model is to provide a visible light positioning hardware system based on CDMA/RF fusion communication.

The purpose of this utility model is achieved through the following technical solutions.

A visible light positioning hardware system based on CDMA/RF fusion communication, including a modulation module, a transmitting module, a transmission module, a receiving module and a demodulation module;

The modulation module is used to realize QPSK modulation, OOK baseband modulation and CDMA spread spectrum; the transmission module includes an LED drive circuit, LED lamps and a transmission antenna; the transmission module includes an optical channel and a radio frequency channel in free space; the The receiving module includes a photoelectric detection device, a wireless signal receiver, an adaptive filter circuit and an amplifying circuit; the demodulation module is used to realize OOK demodulation, QPSK demodulation and CDMA despreading.

Further, the modulation module includes a QPSK modulation module, an OOK baseband modulation module, and a CDMA spread spectrum module.

Further, the transmission module includes an optical channel and a radio frequency channel in free space, the optical channel is used to transmit optical signals, and the radio frequency channel is used to transmit radio frequency signals.

Further, the receiving module includes a photoelectric detection device, a wireless signal receiver, an adaptive filter circuit and an amplification circuit, and the photoelectric detection device receives the optical signal with the ID information of the LED lamp arriving through free space and converts it into an electrical signal, The wireless signal receiver receives the radio frequency signal on the radio frequency channel and converts it into an electrical signal, and the two electrical signals undergo adaptive filtering and amplification processing to filter out noise and obtain an effective signal.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

(1) The structure of the utility model is simple, and by utilizing the orthogonality of the spreading codes in the CDMA modulation technology, while overcoming inter-code interference, the capacity of the channel is increased and the communication quality is improved.

(2) The utility model utilizes the stability of RF communication, is not easily disturbed by environmental factors, and can realize stable communication.

(3) The utility model solves the limitations and deficiencies in coverage of the pure visible light communication system, while maintaining its communication capability based on positioning, and provides better user experience in terms of navigation and positioning services.

(4) The utility model utilizes the directivity of visible light communication and the stability of wireless communication for positioning, and mixes and deploys two different communication technologies to realize technical complementarity.

Description of drawings

FIG. 1 is a schematic diagram of a visible light positioning hardware system based on CDMA/RF fusion communication of the present invention.

detailed description

Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but the embodiment of the utility model is not limited thereto, it should be pointed out that the key of the utility model lies in the technical scheme proposed to the hardware part, relates to the software part All can be realized by those skilled in the art with reference to the prior art.

Example 1

As shown in Figure 1, a visible light positioning system based on CDMA/RF fusion communication includes a modulation module, a transmitting module, a transmission module, a receiving module, and a demodulation module.

The modulation module includes QPSK modulation, OOK baseband modulation and CDMA spread spectrum. The transmitting module includes an LED driving circuit, an LED lamp and a transmitting antenna. The transmission module includes an optical channel and a radio frequency channel in free space. The receiving module includes a photoelectric detection device, a wireless signal receiver, an adaptive filtering circuit and an amplifying circuit. The demodulation module includes OOK demodulation, QPSK demodulation and CDMA despreading.

As an example, the modulation module includes a QPSK modulation module, an OOK baseband modulation module, and a CDMA spread spectrum module. QPSK has four constellation positions. In actual implementation, 00 is mapped to -1-1i, 01 is mapped to -1+1i, 10 is mapped to 1+1i, 11 is mapped to 1+1i, and multiplied by One factor. QPSK adopts 4-ary PSK modulation, each phase can represent two bits of binary information, and its coding efficiency is high. OOK modulation uses a unipolar non-return-to-zero code sequence to control the on and off of the sinusoidal carrier, which has the advantage of being simple and energy-saving. CDMA spread spectrum uses channelization coding, base station code and user code, and multiplies the signal after baseband modulation with user-specific PN code to spread spectrum. The PN code uses m-sequence as channel code and Walsh sequence as address code. The Walsh code can be generated by Hadamard matrix to generate a set of binary sequences with good correlation.

The modulation module carries out CDMA spread spectrum through the signal of QPSK modulation and OOK modulation, and concrete operation is to multiply the modulated signal and user-specific PN code and carry out spread spectrum, and described PN code adopts m sequence as the code of channel, Walsh sequences are encoded as addresses. The Walsh code can be generated by Hadamard matrix to generate a set of binary sequences with good correlation. At the same time, the QPSK modulated data is sent to the transmitting antenna, and the same PN code is used for CDMA spread spectrum at the same time.

The transmission module includes an optical channel and a radio frequency channel in free space, the optical channel is used for transmitting optical signals, and the radio frequency channel is used for transmitting radio frequency signals. A radio frequency channel has a high coverage such that it covers almost the entire space. Only the ID of the LED is transmitted through the optical channel, and CDMA is used to solve the radio frequency interference and visible light interference of adjacent signals.

The receiving module includes a photoelectric detection device, a wireless signal receiver, an adaptive filter circuit and an amplifying circuit. The photoelectric detection device receives the optical signal with the ID information of the LED lamp that arrives through free space and converts it into an electrical signal. The signal receiver receives the radio frequency signal on the radio frequency channel and converts it into an electrical signal. The two circuits of electrical signals are filtered out of noise after adaptive filtering and amplification processing to obtain effective signals.

Further, the spread-spectrum modulated signals are respectively loaded on the driving circuit, and the LED and the transmitting antenna are driven to send optical signals and radio frequency signals respectively, and both the optical signals and the radio frequency signals carry CDMA spreading codes.

Further, the optical channel and the radio frequency channel in the free space transmit optical signals and radio frequency signals respectively. A radio frequency channel has a high coverage such that it covers almost the entire space. Only the ID of the LED is transmitted through the optical channel, and the radio frequency interference and visible light interference between adjacent signals can be solved by using CDMA.

Further, the photoelectric detection device receives the optical signal transmitted by the optical channel and performs photoelectric conversion to convert the optical signal into an electrical signal. The wireless signal receiver receives the radio frequency signal transmitted by the radio frequency channel and converts the radio frequency signal into an electrical signal. Further, the self-adaptive filtering circuit and the amplifying circuit filter and amplify the two electrical signals to filter out noise and amplify effective signals.

Further, the demodulation module performs OOK demodulation on the optical signal received by the optical signal receiving end, and then performs QPSK demodulation on the radio frequency signal received by the wireless signal receiving end and the aforementioned signal after OOK demodulation, and then performs CDMA After despreading, effective information such as the ID of the LED, the signal arrival time difference between the receiving end and the sending end can be obtained. Furthermore, precise positioning can be achieved by using the TOA algorithm to accurately calculate the position of the receiving end. This system has broad market prospects and can be applied to museums, shopping malls, restaurants and intelligent transportation systems, etc.

The specific visible light positioning as an example includes the following steps:

Step 1. Perform QPSK modulation, OOK modulation and CDMA modulation on the ID information of each LED lamp, and the modulated signal drives the LED lamp to emit light signals; at the same time, the transmitting antenna transmits a QPSK-modulated radio frequency signal, which is carried synchronously With CDMA spreading code;

Step 2, the optical signal is transmitted through the optical channel, the radio frequency signal is transmitted through the radio frequency channel, and both the optical channel and the radio frequency channel are located in free space;

Step 3. After the photoelectric detection device at the receiving end receives the visible light signals from each LED lamp, it obtains ID information through corresponding signal processing;

Step 4. According to the orthogonality of the spreading codes, the receiving end uses the spreading code corresponding to the ID obtained on the optical channel to despread the radio frequency signal on the radio frequency channel, thereby realizing accurate calculation of the position of the receiving end.

Described step 1 comprises the following steps:

Step 11, perform QPSK modulation and OOK baseband modulation on the ID information of each LED lamp, and the bandwidth of the modulated signal is B1 _;

Step 12. After the above modulated signal is subjected to a spread spectrum operation by a PN code generator, a spread spectrum signal with a bandwidth of B ₂ is formed, and B ₂ is much larger than B ₁ .

Said step 1 also includes the following steps:

Step 21, performing QPSK modulation on the original radio frequency signal;

Step 22, performing synchronous CDMA spread spectrum processing on the QPSK modulated signal.

Said step 3 includes the following steps:

Step 31, the visible light signal is received by the photoelectric detection device at the receiving end, and an electrical signal is formed after photoelectric conversion;

Step 32, the electrical signal is filtered by an adaptive filter to remove noise, and then processed by an amplification circuit to obtain an effective signal;

Step 33: The CDMA despreading module captures the exact phase of the PN code transmitted by the LED lamp through the built-in synchronization circuit, thereby generating a PN code that is in phase with the sending end and despreading the signal before despreading to restore output ID information.

Described step 4 comprises the following steps:

Step 51. After receiving the radio frequency signal, the receiving end uses the spreading code corresponding to the ID information obtained on the optical channel to despread the signal on the radio frequency channel;

Step 52. The receiving end is equipped with a time detection device. When the signal arrives at the receiving end, the signal arrival time difference between the receiving end and the sending end is obtained, and then the position of the receiving end is accurately calculated using the TOA algorithm.

The above-mentioned embodiment is only one embodiment of the present utility model, but the embodiment of the present utility model is not limited by the above-mentioned embodiment, and any other changes, modifications and substitutions made without departing from the spirit and principle of the present utility model , combination, and simplification should all be equivalent replacement methods, and are all included within the protection scope of the present utility model.

Claims (4)

1. a kind of visible ray alignment system based on CDMA/RF converged communication is it is characterised in that include modulation module, transmitting mould Block, transport module, receiver module and demodulation module；Described modulation module is used for realizing QPSK modulation, OOK baseband modulation and CDMA Spread spectrum；Described transmitter module includes LED drive circuit, LED lamp and transmitting antenna；Described transport module is included in free space Optical channel and radio-frequency channel；Described receiver module includes photoelectricity testing part, wireless signal receiver, auto-adaptive filter circuit And amplifying circuit；Described demodulation module is used for realizing OOK demodulation, QPSK demodulation CDMA despreading.

2. the visible ray alignment system based on CDMA/RF converged communication according to claim 1 is it is characterised in that described tune Molding block includes QPSK modulation module, OOK baseband-modem module, CDMA spread spectrum module.

3. the visible ray alignment system based on CDMA/RF converged communication according to claim 1 is it is characterised in that described biography Defeated module includes optical channel and radio-frequency channel in free space, and optical channel is used for transmitting optical signal, and radio-frequency channel is used for transmitting Radiofrequency signal.

4. the visible ray alignment system based on CDMA/RF converged communication according to claim 1 is it is characterised in that described connect Receive module and include photoelectricity testing part, wireless signal receiver, auto-adaptive filter circuit and amplifying circuit, described photoelectric detector Part receives to be had the optical signal of LED lamp id information and is converted to the signal of telecommunication through what free space reached, described wireless communication Number receiver receives the radiofrequency signal in radio-frequency channel and is converted to the signal of telecommunication, and two path signal is through adaptive-filtering and amplification Filter off noise after process, obtain useful signal.