A three-hop communication system and method from water to sky

Abstract

The present invention relates to the field of communication technology, and specifically to a three-hop communication system and method from water to sky, comprising a plurality of sensor nodes, an underwater relay, a buoy relay and an unmanned aerial vehicle, wherein the sensor node sends information to the underwater relay via a link through an acoustic signal; the underwater relay converts the acoustic signal into optical information and then combines it into an optical wireless link, and sends the optical information to the buoy relay via an optical signal; the buoy relay converts the optical signal into a radio frequency signal and sends it to the unmanned aerial vehicle via an radio frequency link, thereby avoiding energy loss caused by absorption and scattering when directly using optical waves to pass through the sea surface; and the unmanned aerial vehicle receives the radio frequency signal. The underwater communication method combining hydroacoustic and optical wireless is adopted to solve the problem of severe interference from the underwater environment and large propagation attenuation during long-distance underwater transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of communication technologies, and in particular to a water-to-sky three-hop communication system and method. Background Art

[0002] Underwater acoustic communication is the most mature technology at present. Sound waves propagate underwater with low signal attenuation, long transmission distance, and can support temperature-stable deep-water communications of tens of kilometers. The attenuation rate is one thousandth of that of electromagnetic waves. However, since the underwater acoustic link is a very complex medium space, sound waves will be greatly affected by environmental noise, temperature, salinity, etc. during propagation. At the same time, sound waves can hardly propagate across the interface between water and air. This limits the flexibility of the communication system by this method.

[0003] Light waves can provide high-speed data with low power consumption and low quality requirements in air communications. In underwater communications, they have the characteristics of strong information carrying capacity, easy to achieve large-capacity underwater data transmission, and high security and confidentiality. However, during underwater transmission, due to interference from the underwater environment, the propagation attenuation is large, making the propagation distance relatively limited, usually within 100m. Summary of the invention

[0004] The purpose of the present invention is to provide a three-hop communication system and method from water to sky, aiming to solve the problem of severe interference from the underwater environment and large propagation attenuation during underwater transmission.

[0005] To achieve the above-mentioned object, in a first aspect, the present invention provides a three-hop communication system from water to sky, comprising a plurality of sensor nodes, an underwater relay, a buoy relay and a drone, wherein the underwater relay, the buoy relay and the drone are connected in sequence, and the plurality of sensor nodes are all connected to the underwater relay;

[0006] The sensor node is used to send information to the underwater relay via an acoustic signal via an underwater acoustic link;

[0007] The underwater relay is used to convert the acoustic wave signal into optical information and then combine it into an optical wireless link, and send the optical information to the buoy relay via an optical wave signal;

[0008] The buoy relay is used to convert the optical wave signal into a radio frequency signal and send it to the UAV via a radio frequency link;

[0009] The drone is used to receive the radio frequency signal.

[0010] Wherein, the underwater relay comprises a data acquisition module, an acoustic-optical conversion module and a transmission module, and the data acquisition module, the acoustic-optical conversion module and the transmission module are connected in sequence;

[0011] The data acquisition module is used to collect the acoustic wave signal through the hydroacoustic link;

[0012] The acoustic-optical conversion module is used to perform acoustic-optical conversion on the collected acoustic wave signal to obtain optical information, and to combine the optical information into an optical wireless link;

[0013] The transmission module is used to transmit the optical information to the buoy relay via the optical wireless link.

[0014] Wherein, the buoy relay comprises a receiving module, a photoelectric conversion module and a forwarding module, and the receiving module, the photoelectric conversion module and the forwarding module are connected in sequence;

[0015] The receiving module is used to receive the optical information;

[0016] The photoelectric conversion module is used to convert the optical information into a radio frequency signal;

[0017] The forwarding module is used to send the radio frequency signal to the drone via a radio frequency link.

[0018] In a second aspect, the present invention provides a three-hop communication method from water to sky, comprising the following steps:

[0019] The sensor node sends the information to the underwater relay via an acoustic signal via an underwater acoustic link;

[0020] The acoustic wave signal is converted into optical information through an underwater relay and then combined into an optical wireless link, and the optical information is sent to the buoy relay through an optical wave signal;

[0021] The optical wave signal is converted into a radio frequency signal through a buoy relay and sent to the drone via a radio frequency link;

[0022] Receive RF signals via drone.

[0023] The present invention provides a three-hop communication system from water to sky. The sensor node sends information to the underwater relay via an acoustic wave signal via an underwater acoustic link. The underwater relay converts the acoustic wave signal into optical information and then combines it into an optical wireless link, thus realizing the transformation from low-speed underwater acoustic communication to high-speed wireless optical communication, improving the efficiency of communication. The optical information is sent to the buoy relay via an optical wave signal. The buoy relay converts the optical wave signal into an RF signal and sends it to the drone via an RF link, thus avoiding the energy loss caused by absorption and scattering when the light wave is directly used to pass through the sea surface. The RF signal is received by the drone. The underwater communication method combining acoustic and optical wireless solves the problem of severe interference from the underwater environment and large propagation attenuation during long-distance underwater transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The present invention provides a structural diagram of a three-hop communication system from water to sky.

[0026] Figure 2 The present invention provides a three-hop communication system from water to sky, and its interruption performance under different signal-to-noise ratios and underwater turbulence intensities.

[0027] Figure 3 The present invention provides a relationship between the interruption probability of a three-hop communication system from water to sky and the horizontal and vertical distances between an aerial UAV node and a surface buoy relay.

[0028] Figure 4 The present invention provides a relationship between the performance of a three-hop communication system from water to sky and the delay error of underwater acoustic channel state information feedback.

[0029] Figure 5 This is a schematic diagram of a three-hop communication system from water to sky provided by the present invention.

[0030] Figure 6 The present invention provides a flow chart of a three-hop communication system method from water to sky.

[0031] 1-sensor node, 2-underwater relay, 3-buoy relay, 4-drone, 5-data acquisition module, 6-acoustic-optical conversion module, 7-transmission module, 8-receiving module, 9-photoelectric conversion module, 10-forwarding module. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0033] See also Figures 1 to 5In a first aspect, the present invention provides a three-hop communication system from water to sky, comprising a plurality of sensor nodes 1, an underwater relay 2, a buoy relay 3 and a drone 4, wherein the underwater relay 2, the buoy relay 3 and the drone 4 are connected in sequence, and the plurality of sensor nodes 1 are all connected to the underwater relay 2;

[0034] The sensor node 1 is used to send information to the underwater relay 2 via an acoustic signal via an underwater acoustic link;

[0035] The underwater relay 2 is used to convert the acoustic wave signal into optical information and then combine it into an optical wireless link, and send the optical information to the buoy relay 3 via an optical wave signal;

[0036] The buoy relay 3 is used to convert the optical wave signal into a radio frequency signal and send it to the drone 4 via a radio frequency link;

[0037] The drone 4 is used to receive the radio frequency signal.

[0038] Specifically, the underwater relay 2 is an unmanned submersible, and the sensor node 1 sends information to the underwater relay 2 via an acoustic wave signal via an underwater acoustic link; the underwater relay 2 converts the acoustic wave signal into optical information and then compounds it into an optical wireless link, thereby realizing the transformation from low-speed underwater acoustic communication to high-speed wireless optical communication, improving the efficiency of communication, and sending the optical information to the buoy relay 3 via an optical wave signal; the buoy relay 3 converts the optical wave signal into an radio frequency signal and sends it to the drone 4 via an radio frequency link, thereby avoiding the energy loss caused by absorption and scattering when directly using light waves to pass through the sea surface; the radio frequency signal is received by the drone 4, and a communication method combining underwater acoustic and optical wireless is adopted, thereby solving the problem of severe interference from the underwater environment and large propagation attenuation during long-distance underwater transmission.

[0039] Further, the underwater relay 2 includes a data acquisition module 5, an acoustic-optical conversion module 6 and a transmission module 7, and the data acquisition module 5, the acoustic-optical conversion module 6 and the transmission module 7 are connected in sequence;

[0040] The data acquisition module 5 is used to collect the acoustic wave signal through the hydroacoustic link;

[0041] The acoustic-optical conversion module 6 is used to perform acoustic-optical conversion on the collected acoustic wave signal to obtain optical information, and to combine the optical information into an optical wireless link;

[0042] The transmission module 7 is used to transmit the optical information to the buoy relay 3 via the optical wireless link.

[0043] Specifically, the data acquisition module 5 collects the acoustic wave signal through the underwater acoustic link; the acoustic-optical conversion module 6 performs acoustic-optical conversion on the collected acoustic wave signal to obtain optical information, and combines the optical information into an optical wireless link; the transmission module 7 transmits the optical information to the buoy, and the acoustic wave signal received by the underwater relay 2 is represented by y 1 =h k x+n 1 , where h k represents the channel gain between the selected sensor node 1 and the relay, n 1 is additive white Gaussian noise, x is the transmitted signal, the transmission module 7 transmits the optical information to the buoy through a beam of light waves (blue-green light), assuming that there are three sensor nodes 1, there are three hydroacoustic links between the three sensor nodes 1 and the underwater relay 2, first assume that the average signal-to-noise ratios of the three links are all equal. Figure 4 The system is shown in Figure 2 at different signal-to-noise ratios. and underwater turbulence intensity (given by the scintillation index As the scintillation index decreases, that is, the turbulence intensity decreases, the system outage probability gradually decreases. As the link signal-to-noise ratio increases, the system achieves good outage performance. Figure 5 The figure shows the system outage probability and the horizontal distance r between the aerial drone 4 node and the surface buoy relay 3 when the scintillation index value is 0.1484. UAV And the relationship between the vertical distance h. It can be seen that the interruption probability decreases first and then increases with h, indicating that when the horizontal distance is constant, there is an optimal height of UAV 4 that makes the system interruption performance the best. When the vertical height is constant, the interruption probability of the system increases with the increase of horizontal distance. This is because the increase of horizontal distance means the reduction of the coverage range of UAV 4.

[0044] Figure 6 The figure shows the relationship between system performance and delay error of underwater acoustic channel state information feedback (reflected by correlation coefficient ρ) when the flicker index value is 0.4201. When the value of ρ is closer to 1, that is, the delay error is smaller (a value of 1 indicates no error), the interruption probability of the system is lower.

[0045] Furthermore, the buoy relay 3 includes a receiving module 8, a photoelectric conversion module 9 and a forwarding module 10, and the receiving module 8, the photoelectric conversion module 9 and the forwarding module 10 are connected in sequence;

[0046] The receiving module 8 is used to receive the optical information;

[0047] The photoelectric conversion module 9 is used to convert the optical information into a radio frequency signal;

[0048] The forwarding module 10 is used to send the radio frequency signal to the drone via a radio frequency link.

[0049] Specifically, the receiving module 8 receives the optical information; the photoelectric conversion module 9 converts the optical information into a radio frequency signal; the forwarding module 10 sends the radio frequency signal to the drone via a radio frequency link, and the optical information received by the buoy relay 3 is expressed as y=Iη(h k x+n 1 )+n 2 , where I is the optical wireless channel gain, which is related to absorption, scattering, and underwater turbulence intensity, η is the acoustic-optical conversion coefficient, and n 2 is additive Gaussian white noise. Both underwater relay 2 and buoy relay 3 use a decoding and forwarding protocol, that is, the received signal is demodulated, and after decoding, it is still encoded using the original encoding method and then sent to the destination node. Specifically, a cyclic redundancy check is used to determine whether the correct data packet is received. If it is correct, it is forwarded, and if it is incorrect, it is discarded.

[0050] See also Figure 6 In a second aspect, the present invention provides a three-hop communication method from water to sky, comprising the following steps:

[0051] S101 sends information to the underwater relay 2 through the sensor node 1 via an acoustic signal via an underwater acoustic link;

[0052] Specifically, the sound wave signal received by the underwater relay 2 is represented by y 1 =h k x+n 1 , where h k represents the channel gain between the selected sensor node 1 and the relay, n 1 is additive white Gaussian noise, and x is the transmitted signal.

[0053] S102 converts the acoustic wave signal into optical information through the underwater relay 2 and then combines it into an optical wireless link, and sends the optical information to the buoy relay 3 through the optical wave signal;

[0054] S103 converts the optical wave signal into a radio frequency signal through the buoy relay 3 and sends it to the drone 4 via a radio frequency link;

[0055] Specifically, the optical signal received by the buoy relay 3 is expressed as y=Iη(h k x+n 1 )+n 2 ,

[0056] Where I is the optical wireless channel gain, which is related to absorption, scattering, and underwater turbulence intensity, η is the acousto-optic conversion coefficient, and n2 is additive Gaussian white noise, which converts the optical signal into a radio frequency signal and sends it to the drone 4 via the radio frequency link

[0057] S104 receives the radio frequency signal through the drone 4.

[0058] Beneficial effects:

[0059] In the present invention, for communication nodes in deeper sea areas, information communication is carried out by transmitting sound waves, which reduces a large amount of transmission loss caused by long-distance transmission compared to traditional optical communication systems and improves the stability of communication.

[0060] In the present invention, the underwater relay is used to obtain the channel state information of the underwater acoustic channel, which schedules the channel to the user with the best channel condition and aggregates as many underwater acoustic messages as possible into a wireless optical communication link and transmits them to the buoy relay 3 on the sea surface, thereby maximizing the capacity of the system.

[0061] In the present invention, the characteristics of the three communication technologies are fully utilized. First, the multi-channel hydroacoustic links are converged to the relay node and then combined into the optical wireless link, realizing the transformation from low-speed hydroacoustic communication to high-speed wireless optical communication, thereby improving the communication efficiency. Finally, in the water buoy relay 3, the received optical signal is converted into a radio frequency signal and transmitted to the drone 4, avoiding the energy loss caused by absorption and scattering when directly using light waves to pass through the sea surface, thereby completing the deep sea-air communication and expanding the communication range of the system.

[0062] What is disclosed above is only a preferred embodiment of a three-hop communication system and method from water to sky of the present invention. Of course, it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention are still within the scope of the invention.

Claims

1. A three-hop communication system from water to sky, characterized in that: It includes a plurality of sensor nodes, an underwater relay, a buoy relay and a drone, wherein the underwater relay, the buoy relay and the drone are connected in sequence, and the plurality of sensor nodes are all connected to the underwater relay; The sensor node is used to send information to the underwater relay via an acoustic signal via an underwater acoustic link; The underwater relay is used to convert the acoustic wave signal into optical information and then combine it into an optical wireless link, and send the optical information to the buoy relay via an optical wave signal; The buoy relay is used to convert the optical wave signal into a radio frequency signal and send it to the UAV via a radio frequency link; The drone is used to receive the radio frequency signal.

2. The water-to-sky three-hop communication system according to claim 1, characterized in that: The underwater relay includes a data acquisition module, an acoustic-optical conversion module and a transmission module, and the data acquisition module, the acoustic-optical conversion module and the transmission module are connected in sequence; The data acquisition module is used to collect the acoustic wave signal through the hydroacoustic link; The acoustic-optical conversion module is used to perform acoustic-optical conversion on the collected acoustic wave signal to obtain optical information, and to combine the optical information into an optical wireless link; The transmission module is used to transmit the optical information to the buoy relay via the optical wireless link.

3. The water-to-sky three-hop communication system according to claim 2, characterized in that: The buoy relay includes a receiving module, a photoelectric conversion module and a forwarding module, and the receiving module, the photoelectric conversion module and the forwarding module are connected in sequence; The receiving module is used to receive the optical information; The photoelectric conversion module is used to convert the optical information into a radio frequency signal; The forwarding module is used to send the radio frequency signal to the drone via a radio frequency link.

4. A three-hop communication method from water to sky, applied to the three-hop communication system from water to sky as claimed in claim 3, characterized in that: The following steps are involved: The sensor node sends the information to the underwater relay via an acoustic signal via an underwater acoustic link; The acoustic wave signal is converted into optical information through an underwater relay and then combined into an optical wireless link, and the optical information is sent to the buoy relay through an optical wave signal; The optical wave signal is converted into a radio frequency signal through a buoy relay and sent to the drone via a radio frequency link; Receive RF signals via drone.

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