CN112953637A - Indoor visible light communication method and system based on DCO-OFDM and adopting relay assistance - Google Patents

Indoor visible light communication method and system based on DCO-OFDM and adopting relay assistance Download PDF

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CN112953637A
CN112953637A CN202110216416.7A CN202110216416A CN112953637A CN 112953637 A CN112953637 A CN 112953637A CN 202110216416 A CN202110216416 A CN 202110216416A CN 112953637 A CN112953637 A CN 112953637A
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陈墨
胡天宇
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University of Science and Technology Beijing USTB
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/116—Visible light communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/29—Repeaters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2697—Multicarrier modulation systems in combination with other modulation techniques
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/14—Two-way operation using the same type of signal, i.e. duplex
    • H04L5/16—Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission

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Abstract

The invention discloses a DCO-OFDM-based indoor visible light communication method and system with relay assistance, wherein the method comprises the following steps: in the broadcasting stage, a source end modulates a signal to be transmitted based on a DCO-OFDM method and simultaneously transmits the modulated signal to a relay end and a destination end; in the relay stage, the source end does not send a signal, the relay end decodes and modulates the signal from the source end and forwards the modulated signal to the destination end; the destination then combines the signals received in the two stages according to the maximum ratio. The invention solves the technical problems that different objects in the existing visible light communication system can cause different propagation phenomena, and a link between a sending end and a receiving end is easy to be blocked, so that the performance of the whole communication system is influenced, and even communication is interrupted. The time and space resources of the whole system are effectively utilized, and the communication performance is improved.

Description

Indoor visible light communication method and system based on DCO-OFDM and adopting relay assistance
Technical Field
The invention relates to the technical field of visible light communication, in particular to a DCO-OFDM-based indoor visible light communication method and system with relay assistance.
Background
With the rapid development of scientific technology and the continuous improvement of living standard of people, people have higher requirements on Communication speed and Communication quality, and Visible Light Communication (VLC) is an emerging wireless optical Communication technology developed based on LED technology, which just gives it unlimited opportunities and challenges. The visible light communication technology is a high-speed communication mode which uses light in a visible light wave band as an information carrier and transmits information by using high-speed bright and dark flashing signals which are emitted by fluorescent lamps, light-emitting diodes and the like and cannot be seen by naked eyes. The VLC technology which gives consideration to both illumination and communication provides a flexible solution for rapid deployment of indoor wireless broadband access. Compared with other communication modes, the VLC has the advantages of being rich in frequency spectrum, high in confidentiality, green, environment-friendly and the like.
However, in the indoor VLC system, due to the short transmission distance, many obstacles, and complex and variable propagation modes, different objects may cause different propagation phenomena, such as: reflection, refraction, diffraction and scattering, the link between the transmitting end and the receiving end is easily blocked, and at this time, the performance of the whole communication system is deteriorated, and even communication is interrupted.
Disclosure of Invention
The invention provides a DCO-OFDM-based indoor visible light communication method and system with relay assistance, and aims to solve the technical problems that in an existing indoor visible light communication system, different objects can cause different propagation phenomena, and a link between a sending end and a receiving end is easily blocked, so that the performance of the whole communication system is influenced, and even communication interruption can be caused.
In order to solve the technical problems, the invention provides the following technical scheme:
on one hand, the invention provides a DCO-OFDM-based indoor visible light communication method adopting relay assistance, which is suitable for indoor scenes, wherein the scenes comprise a source end, a relay end and a destination end; the source end and the relay end both have the functions of illumination and optical communication; the source end, the relay end and the destination end adopt a half-duplex orthogonal cooperation protocol for communication, and the indoor visible light communication method comprises the following steps:
in a broadcasting stage, the source terminal modulates a signal to be transmitted based on a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) method, and simultaneously transmits the modulated signal to the relay terminal and the destination terminal;
in a relay stage, the source end does not send a signal, the relay end decodes and modulates the signal from the source end based on a DCO-OFDM method, and forwards the modulated signal to the destination end;
and the destination end combines the signal sent by the source end in the broadcasting stage and the signal sent by the relay end in the relay stage, and demodulates the combined signal to obtain the information content sent by the source end.
Further, the height of the relay terminal is adjustable.
Further, the merging, by the destination, the signal sent by the source in the broadcast stage and the signal sent by the relay in the relay stage, including:
and the destination terminal combines the signal sent by the source terminal in the broadcast stage and the signal sent by the relay terminal in the relay stage according to the maximum ratio.
Further, the available optical orthogonal frequency division multiplexing, OFDM, signal energy of the broadcast phase and the relay phase is set to 2E in terms of average power calculation; where E is the energy per slot.
Further, the source terminal and the relay terminal are respectively allocated with 2EKEAnd 2E (1-K)E) The signal energy of (a).
Further, the relay cooperation mode adopted by the relay terminal is amplify-forward or decode-retransmit.
On the other hand, the invention also provides an indoor visible light communication system based on DCO-OFDM and adopting relay assistance, and the indoor visible light communication system comprises: a source terminal, a relay terminal and a destination terminal; the source end and the relay end both have the functions of illumination and optical communication;
in the DCO-OFDM-based indoor visible light communication system adopting relay assistance, the source end, the relay end and the target end adopt a half-duplex orthogonal cooperation protocol for communication;
in a broadcasting stage, the source terminal modulates a signal to be transmitted based on a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) method, and simultaneously transmits the modulated signal to the relay terminal and the destination terminal;
in a relay stage, the source end does not send a signal, the relay end decodes and modulates the signal from the source end based on a DCO-OFDM method, and forwards the modulated signal to the destination end;
and the destination end combines the signal sent by the source end in the broadcasting stage and the signal sent by the relay end in the relay stage, and demodulates the combined signal to obtain the information content sent by the source end.
Further, the height of the relay terminal is adjustable.
Further, the destination is specifically configured to: and combining the signals sent by the source end in the broadcast stage and the signals sent by the relay end in the relay stage according to the maximum ratio.
Further, the available optical orthogonal frequency division multiplexing, OFDM, signal energy of the broadcast phase and the relay phase is set to 2E in terms of average power calculation; wherein E is energy per time slot;
the source terminal and the relay terminal are respectively distributed with 2EKEAnd 2E (1-K)E) The signal energy of (a);
the relay cooperation mode adopted by the relay terminal is amplification forwarding or decoding retransmission.
The technical scheme provided by the invention has the beneficial effects that at least:
the invention uses direct current biased light orthogonal frequency division multiplexing (DCO-OFDM) method and half-duplex orthogonal cooperation protocol in VLC system, analyzes the blocking condition in the room by the cooperation of the relay light source and the main light source, selects several relay positions meeting the condition, and selects the best relay position by combining the power distribution. The time and space resources of the whole system are effectively utilized, and the communication performance is improved.
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In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flowchart of an indoor visible light communication method using relay assistance based on DCO-OFDM according to an embodiment of the present invention;
fig. 2 is a schematic room model diagram of an indoor visible light communication system with relay assistance based on DCO-OFDM according to an embodiment of the present invention.
Description of reference numerals:
1. a source end; 2. a relay terminal; 3. and a destination terminal.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First embodiment
The embodiment provides a DCO-OFDM-based indoor visible light communication method adopting relay assistance, which is suitable for an indoor scene, wherein the scene has two light sources, and the method comprises the following steps: a source terminal, a relay terminal and a destination terminal; the source end and the relay end both have the functions of illumination and optical communication; the destination end is arranged on a computer on the desktop in the form of a USB receiver; in the embodiment, the lamp on the desktop is taken into consideration, the lamp on the ground is taken as the relay lamp, and the height of the relay lamp is adjustable;
in this embodiment, the relay end does not access the backbone network, but receives the information from the source end and forwards the information to the destination end; and uses a half-duplex orthogonal cooperation protocol. The protocol consists of two phases, a broadcast phase and a relay phase. Specifically, the execution flow of the method is shown in fig. 1, and includes the following steps:
s1, in the broadcast stage, the source terminal modulates the signal to be transmitted based on the direct current biased optical orthogonal frequency division multiplexing DCO-OFDM method, and transmits the modulated signal to the relay terminal and the destination terminal at the same time;
s2, in the relay stage, the source end does not send signals, the relay end decodes and modulates the signals from the source end based on the DCO-OFDM method, and forwards the modulated signals to the destination end;
and S3, the destination terminal combines the signal sent by the source terminal in the broadcast stage and the signal sent by the relay terminal in the relay stage, and demodulates the combined signal to obtain the information content sent by the source terminal.
Further, in this example, the manner in which the destination terminal combines the signal sent by the source terminal in the broadcast phase and the signal sent by the relay terminal in the relay phase is as follows: and combining the signals sent by the source end in the broadcast stage and the signals sent by the relay end in the relay stage according to the maximum ratio.
Specifically, in the implementation of the DCO-OFDM-based indoor visible light communication method with relay assistance, such as phase modulation (PSK) or Quadrature Amplitude Modulation (QAM), the input bit stream is first mapped to the complex symbol s. The input vector X is subjected to an inverse fast fourier transform (N-IFFT) to form a discrete signal X N. Real and non-negative x [ n ] is communicated optically by intensity modulation and direct detection (IM/DD).
Wherein the available OFDM signal energy of the two cooperation phases is set to 2E in terms of average power calculation, which is also proportional to the energy per slot E. The optimal power distribution of the source terminal and the relay terminal is determined by the minimum bit error rate of the relay cooperative system. Lead-in source coefficient KLThe distribution of the number of the LED chips of the source end and the relay end is determined by representing the proportion of the number of the LED chips of the source end to the total number of the LEDs. Introduction of a Performance parameter KEAnd the optimal power distribution of the source and the relay end is determined by the minimum bit error rate of the AF relay cooperation system. Due to the negative exponential relationship, the minimum bit error rate is equal to the maximum signal-to-noise ratio. And since the most primitive task of a lighting device is lighting, it is adjustedIntegral parameter KLTo the required illumination ratio and setting the parameter KETo optimize communication performance. KERIs a performance parameter in the event of congestion. KEAnd KERFrom KLAnd the correlation gain is calculated. The LEDs at the source end and the relay end are respectively distributed with 2EKEAnd 2E (1-K)E) The signal energy of (a). Another parameter KLThe proportion of the number of the LED chips of the source end and the relay end is controlled. It is assumed that all LEDs between the source and relay terminals have the same dc offset value. X is to bes(t) is defined as a power of 2EKEThe source terminal of (1) transmits a signal.
Figure BDA0002953943630000041
Defined as a power of 2E (1-K)E) The relay terminal of (2) transmits a signal. Then, the received electrical signal at the destination and the electrical signal received at the relay in the first stage are yD1(t) and yR(t) of (d). In the amplify-and-forward mode, the relay terminal has a simple amplifying function on the received signal. The signal received by the destination terminal in the relay stage is yD2(t), the destination then combines the received signals of the two stages according to the maximum ratio.
The relay cooperation mode adopted by the relay cooperation system is amplify-and-forward AF or decode-and-retransmit DF.
Optimum K for DCO-OFDM VLC system for AF relayL,KE,KERAs shown in table 1.
TABLE 1 optimal K for AF relayed DCO-OFDM VLC systemL,KE,KER
Figure BDA0002953943630000051
Figure BDA0002953943630000061
Optimal K of DCO-OFDM VLC system of DF relayL,KE,KERAs shown in table 2.
TABLE 2 DF relayed DCOptimum K for O-OFDM VLC systemL,KE
Figure BDA0002953943630000062
Figure BDA0002953943630000071
In summary, in the present embodiment, a direct current biased light orthogonal frequency division multiplexing (DCO-OFDM) method and a half-duplex orthogonal cooperation protocol are used in the VLC system, and the blocking condition in the room is analyzed by the cooperation of the relay light source and the main light source; the advantages brought by the OFDM technology in optical communication are as follows: the linear damage of the electric signal is compensated, a high-order modulation mode is easy to realize, a system can select partial subcarriers to modulate and demodulate, and linear intermodulation distortion can be ignored. The relay technology has the characteristics of coverage increase, capacity improvement, transmission power reduction and flexible and rapid deployment in the wireless field. The relay technology is introduced into the technical field of visible light communication, a system structure of a source end-relay end-terminal is formed, and time and space resources of the whole system are effectively utilized. Thereby effectively utilizing time and space resources of the entire system and improving communication performance.
Second embodiment
The embodiment provides an indoor visible light communication system based on DCO-OFDM and adopting relay assistance, wherein an applicable scene is a typical office area, and a model of the system is shown in fig. 2; the system comprises: a source end 1, a relay end 2 and a destination end 3; the source end 1 and the relay end 2 both have the functions of illumination and optical communication; the destination end 3 is arranged on a computer on a desktop in the form of a USB receiver; in the embodiment, the lamp on the desktop is taken into consideration, the lamp on the ground is taken as the relay lamp, and the height of the relay lamp is adjustable;
in this embodiment, the relay end 2 does not access the backbone network, but receives the information from the source end 1 and forwards the information to the destination end 3; and uses a half-duplex orthogonal cooperation protocol. The protocol consists of two phases, a broadcast phase and a relay phase. In a broadcasting stage, the source end 1 modulates a signal to be transmitted based on a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) method, and simultaneously transmits the modulated signal to the relay end 2 and the destination end 3; in the relay stage, the source end 1 does not send signals, only the relay end 2 forwards information, and the relay end 2 decodes and modulates the signals from the source end based on a DCO-OFDM method and forwards the modulated signals to the destination end 3; and the destination terminal 3 combines the signal sent by the source terminal 1 in the broadcast stage and the signal sent by the relay terminal 2 in the relay stage according to the maximum ratio, and demodulates the combined signal to obtain the information content sent by the source terminal 1.
Specifically, in the deployment of the indoor visible light communication system with relay assistance based on DCO-OFDM of the present embodiment, such as phase modulation (PSK) or Quadrature Amplitude Modulation (QAM), the input bit stream is first mapped to the complex symbol s. The input vector X is subjected to an inverse fast fourier transform (N-IFFT) to form a discrete signal X N. Real and non-negative x [ n ] is communicated optically by intensity modulation and direct detection (IM/DD).
Wherein the available OFDM signal energy of the two cooperation phases is set to 2E in terms of average power calculation, which is also proportional to the energy per slot E. The optimal power allocation of the source terminal 1 and the relay terminal 2 is determined by the minimum bit error rate of the relay cooperative system. Lead-in source coefficient KLThe ratio of the number of LED chips of the source terminal 1 to the total number of LEDs is shown, that is, the distribution of the number of LED chips of the source terminal 1 and the relay terminal 2 is determined. Introduction of a Performance parameter KEThe optimal power allocation of the source terminal 1 and the relay terminal 2 is determined by the minimum bit error rate of the AF relay cooperative system. Due to the negative exponential relationship, the minimum bit error rate is equal to the maximum signal-to-noise ratio. And since the most primitive task of the lighting device is lighting, the parameter K is adjustedLTo the required illumination ratio and setting the parameter KETo optimize communication performance. KERIs a performance parameter in the event of congestion. KEAnd KERFrom KLAnd the correlation gain is calculated. The LEDs at the source end 1 and the relay end 2 are respectively distributed with 2EKEAnd 2E (1-K)E) The signal energy of (a). Another parameter KLThe proportion of the number of the LED chips of the source end 1 and the relay end 2 is controlled. It is assumed that all LEDs between the source 1 and the relay 2 have the same dc offset value. X is to bes(t) is defined as a power of 2EKEThe source terminal 1 transmits a signal.
Figure BDA0002953943630000082
Defined as a power of 2E (1-K)E) The relay terminal 2 of (2) transmits a signal. Then, the electrical signal received by the destination terminal 3 and the electrical signal received by the relay terminal 2 in the first stage are yD1(t) and yR(t) of (d). In the amplify-and-forward mode, the relay terminal 2 has a simple amplifying function on the received signal. The signal received by the destination terminal 3 in the relay stage is yD2(t), the destination terminal 3 will then combine the received signals of the two stages according to the maximum ratio.
The relay cooperation mode adopted by the relay cooperation system is amplify-and-forward AF or decode-and-retransmit DF.
Optimum K for DCO-OFDM VLC system for AF relayL,KE,KERAs shown in table 1.
TABLE 1 optimal K for AF relayed DCO-OFDM VLC systemL,KE,KER
Figure BDA0002953943630000081
Figure BDA0002953943630000091
Optimal K of DCO-OFDM VLC system of DF relayL,KE,KERAs shown in table 2.
TABLE 2 optimal K for DCO-OFDM VLC system for DF relayingL,KE
Figure BDA0002953943630000092
Figure BDA0002953943630000101
In summary, in the present embodiment, a direct current biased light orthogonal frequency division multiplexing (DCO-OFDM) method and a half-duplex orthogonal cooperation protocol are used in the VLC system, and the blocking condition in the room is analyzed by the cooperation of the relay light source and the main light source; the advantages brought by the OFDM technology in optical communication are as follows: the linear damage of the electric signal is compensated, a high-order modulation mode is easy to realize, a system can select partial subcarriers to modulate and demodulate, and linear intermodulation distortion can be ignored. The relay technology has the characteristics of coverage increase, capacity improvement, transmission power reduction and flexible and rapid deployment in the wireless field. The relay technology is introduced into the technical field of visible light communication, a system structure of a source end-relay end-terminal is formed, and time and space resources of the whole system are effectively utilized. Thereby effectively utilizing time and space resources of the entire system and improving communication performance.
Furthermore, it should be noted that the present invention may be provided as a method, apparatus or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media having computer-usable program code embodied in the medium.
Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.
Finally, it should be noted that while the above describes a preferred embodiment of the invention, it will be appreciated by those skilled in the art that, once the basic inventive concepts have been learned, numerous changes and modifications may be made without departing from the principles of the invention, which shall be deemed to be within the scope of the invention. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.

Claims (10)

1. An indoor visible light communication method based on DCO-OFDM and adopting relay assistance is suitable for indoor scenes, wherein the scenes comprise a source end, a relay end and a destination end; the source end and the relay end both have the functions of illumination and optical communication; the indoor visible light communication method is characterized in that the source end, the relay end and the destination end adopt a half-duplex orthogonal cooperation protocol for communication, and the indoor visible light communication method comprises the following steps:
in a broadcasting stage, the source terminal modulates a signal to be transmitted based on a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) method, and simultaneously transmits the modulated signal to the relay terminal and the destination terminal;
in a relay stage, the source end does not send a signal, the relay end decodes and modulates the signal from the source end based on a DCO-OFDM method, and forwards the modulated signal to the destination end;
and the destination end combines the signal sent by the source end in the broadcasting stage and the signal sent by the relay end in the relay stage, and demodulates the combined signal to obtain the information content sent by the source end.
2. The DCO-OFDM-based indoor visible light communication method using relay assist according to claim 1, wherein a height of the relay terminal is adjustable.
3. The DCO-OFDM-based indoor visible light communication method using relay assist according to claim 1, wherein the destination end combines a signal transmitted by the source end in a broadcast phase and a signal transmitted by the relay end in a relay phase, and the method comprises:
and the destination terminal combines the signal sent by the source terminal in the broadcast stage and the signal sent by the relay terminal in the relay stage according to the maximum ratio.
4. The DCO-OFDM-based indoor visible light communication method with relay assistance according to claim 1, wherein an available optical orthogonal frequency division multiplexing, OFDM, signal energy of the broadcasting stage and the relaying stage is set to 2E in terms of average power calculation; where E is the energy per slot.
5. The DCO-OFDM-based indoor visible light communication method using relay assistance according to claim 1, wherein the source terminal and the relay terminal are respectively allocated 2EKEAnd 2E (1-K)E) The signal energy of (a).
6. The DCO-OFDM-based indoor visible light communication method adopting relay assistance as claimed in claim 1, wherein the relay cooperation mode adopted by the relay end is amplify-forward or decode-retransmit.
7. An indoor visible light communication system based on DCO-OFDM and adopting relay assistance comprises a source end, a relay end and a destination end; the source end and the relay end both have the functions of illumination and optical communication; the DCO-OFDM-based indoor visible light communication system adopting relay assistance is characterized in that a source end, a relay end and a target end communicate with each other by adopting a half-duplex orthogonal cooperation protocol;
in a broadcasting stage, the source terminal modulates a signal to be transmitted based on a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) method, and simultaneously transmits the modulated signal to the relay terminal and the destination terminal;
in a relay stage, the source end does not send a signal, the relay end decodes and modulates the signal from the source end based on a DCO-OFDM method, and forwards the modulated signal to the destination end;
and the destination end combines the signal sent by the source end in the broadcasting stage and the signal sent by the relay end in the relay stage, and demodulates the combined signal to obtain the information content sent by the source end.
8. The DCO-OFDM-based indoor visible light communication system employing relay assist according to claim 7, wherein a height of the relay terminal is adjustable.
9. The DCO-OFDM-based indoor visible light communication system employing relay assist according to claim 7, wherein the destination is specifically configured to: and combining the signals sent by the source end in the broadcast stage and the signals sent by the relay end in the relay stage according to the maximum ratio.
10. The DCO-OFDM-based indoor visible light communication system with relay assistance according to claim 7, wherein an available optical orthogonal frequency division multiplexing, OFDM, signal energy of the broadcasting stage and the relaying stage is set to 2E in terms of average power calculation; wherein E is energy per time slot;
the source terminal and the relay terminal are respectively distributed with 2EKEAnd 2E (1-K)E) The signal energy of (a);
the relay cooperation mode adopted by the relay terminal is amplification forwarding or decoding retransmission.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017125747A1 (en) * 2016-01-19 2017-07-27 Qatar Foundation For Education, Science And Community Development A relay-assisted visible light communication system
CN108494484A (en) * 2018-03-19 2018-09-04 山东大学 The working method of indoor VLC spatial modulation systems based on IHDAF agreements
CN110808769A (en) * 2019-11-13 2020-02-18 大连理工大学 Wireless energy-carrying communication method based on OFDM (orthogonal frequency division multiplexing) amplification forwarding cooperative relay

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017125747A1 (en) * 2016-01-19 2017-07-27 Qatar Foundation For Education, Science And Community Development A relay-assisted visible light communication system
CN108494484A (en) * 2018-03-19 2018-09-04 山东大学 The working method of indoor VLC spatial modulation systems based on IHDAF agreements
CN110808769A (en) * 2019-11-13 2020-02-18 大连理工大学 Wireless energy-carrying communication method based on OFDM (orthogonal frequency division multiplexing) amplification forwarding cooperative relay

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
REFIK CAGLAR KIZILIRMAK ET AL.: "《2014 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom)》", 30 May 2014 *
REFIK CAGLAR KIZILIRMAK ET AL.: "Relay-Assisted OFDM-Based Visible Light Communications", 《IEEE TRANSACTIONS ON COMMUNICATIONS》 *

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