Site-assisted D2D communication method under short-wave communication system
By using a site-assisted D2D communication method, dynamically allocating frequency points and utilizing ionospheric monitoring, the problems of low reliability and resource consumption in shortwave D2D communication are solved, and efficient end-to-end communication is achieved.
Patent Information
- Application Number
- CN202511242774.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2026-01-13
AI Technical Summary
Existing shortwave D2D communication has low reliability, is highly dependent on ionospheric state, is difficult to adaptively select frequencies, and has high resource consumption, long link establishment time, large transmission delay and is prone to congestion when relaying at sites.
The site-assisted D2D communication method is adopted. The site and the terminal agree on a fixed frequency table and ID, dynamically allocate frequency points, and use ionospheric monitoring to calculate the midpoint coordinates for adaptive frequency point selection, thus avoiding dual resource consumption and decoding and remodulation operations.
It improves communication reliability, reduces link congestion and transmission delay, optimizes channel resource utilization, and solves the inherent defects of traditional shortwave D2D communication.
Smart Images
Figure CN121334892A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of shortwave communication, and specifically relates to a site-assisted D2D communication method in a shortwave communication system. Background Technology
[0002] In existing shortwave (3MHz-30MHz) communication systems, terminal-to-terminal communication mainly takes two forms: direct D2D communication and site relay communication. Direct D2D communication is more widely used; for example, amateur radio operators can adjust frequencies and antennas to receive or transmit shortwave signals for connectionless communication. Furthermore, some devices supporting the ALE protocol can establish links based on fixed frequency points specified in the protocol, thus achieving connection-based communication. Site relay communication modes include... Figure 1 As shown, there is no direct link between terminals; communication between them relies on a "terminal-site-terminal" link. In this case, the terminal needs to establish a connection with the site first, and then communicate through the "terminal-site-terminal" link.
[0003] Existing shortwave D2D communication has the following drawbacks: 1. Traditional shortwave D2D communication has low reliability, is highly dependent on ionospheric states, and is difficult to adaptively select frequencies based on actual channel characteristics; 2. In site relay communication, maintaining the links between terminals requires certain resources. Due to limited site resources, congestion or even collisions can occur when a large number of terminals need to communicate with each other; 3. In site relay communication, after the transmitting terminal's signal arrives at the site, the site needs to decode and remodulate it before forwarding it to the receiving terminal, resulting in excessively long link establishment time and significant transmission delay; 4. In site relay communication, the "terminal-site-terminal" link consumes more channel resources. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a site-assisted D2D communication method in a shortwave communication system to solve the problems of low reliability, congestion and long delay in traditional shortwave D2D communication.
[0005] Technical solution: To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0006] A site-assisted D2D communication method in a shortwave communication system includes the following steps:
[0007] Step 1: The site and the terminal agree on a fixed frequency table, terminal ID, and terminal serial number;
[0008] Step 2: All terminals scan the fixed frequency table; the station broadcasts to all terminals using the fixed frequency table.
[0009] Step 3: If the terminal receives broadcast information from the station, it reports its location information, status information, and requests to establish a D2D link.
[0010] Step 4: When the station receives a D2D link request from a terminal, it checks whether the target terminal has reported the data. If the target terminal has reported the data, the station calculates the coordinates of the midpoint of the connection between the two terminals based on their location information. It then performs ionospheric monitoring based on these coordinates, evaluates each frequency point, and assigns one or more frequency points to the two terminals.
[0011] Step 5: If the station in Step 4 broadcasts that the requested link is feasible, the terminal scans the frequency points allocated by the station, and the master terminal makes cyclic calls on these frequency points; otherwise, the terminal repeats Step 2.
[0012] Step 6: If a call is received from the main terminal at step 5, then reply; otherwise, both terminals repeat step 5.
[0013] Step 7: If the master terminal receives a reply from the slave terminal in step 6, it sends an ACK signal; otherwise, both terminals repeat step 5.
[0014] Step 8: If the terminal receives the ACK signal from the master terminal at step 7, the D2D link establishment is successful; otherwise, the terminal repeats step 5. If the D2D link establishment is not completed within the preset time or the D2D communication ends, both terminals return to step 2.
[0015] Preferably, in step 2, the scanning period of the terminal is T. s =N sc ×T d , where N sc T represents the number of selectable frequencies in the fixed frequency table. d Let T be the dwell time of the terminal at each frequency point. d If a broadcast signal is detected, the dwell time on that frequency will be extended to decode the information in the short frame; if the extended dwell time T... dsf =2T sf Once the correct information is decoded, the terminal will continue to reside on that frequency to decode subsequent short frames until the source ID, T, is decoded. sf For the duration of a short frame; if in T dsf The correct information was not found or the longest dwell time T was not found. wce If the source ID is not decoded, the terminal switches to the next frequency and continues scanning.
[0016] Preferably, in step 2, the station broadcasts on a single frequency, and the broadcast signal structure consists of a broadcast feature signal, carried information, and a source ID. The broadcast feature signal consists of multiple repeating short frames with a duration T. sc The scanning cycle is longer than that of the terminal, and the information it carries consists of an integer number of short frames, including the current D2D link information; the source ID occupies one short frame.
[0017] Preferably, in step 3, after the terminal correctly receives the broadcast from the station, the reply signal structure consists of the destination ID, the information carried, and the source ID; wherein the destination ID and the source ID occupy one short frame, and the information carried occupies multiple short frames. The information includes location information and status information, wherein the status information includes three types: idle, non-idle, and requesting D2D communication.
[0018] Preferably, in step 3, all terminals use time-division multiplexing to reply, dividing the time after the station finishes sending the end flag into different time slots. Each terminal sends according to its priority number in the corresponding time slot. In the first time slot, the station performs a send / receive switch, and the terminal does not reply.
[0019] Preferably, in step 4, after receiving a response from the terminal, the station records the terminal's location and status; the cycle is based on the terminal broadcasting to all frequencies in the fixed frequency table once. If the station does not receive a response from a terminal within a cycle, it will automatically set the terminal's status to non-idle; after receiving a D2D communication request from a terminal, if the target terminal's status is idle, the station will calculate the coordinates of the midpoint of the connection between the two terminals based on their location information, then perform ionospheric monitoring based on the coordinates, select one or more frequencies, and determine the master and slave terminals for D2D link establishment, then write them into the information section of the broadcast; finally, the station sets the status of both terminals to non-idle.
[0020] Preferably, in step 4, after the station obtains the positions of the two terminals, it calculates the coordinates of the midpoint M; then the station controls the beam to point to point M, and steps to detect and record the echo energy in the 3MHz-30MHz frequency band, and selects one or more frequency points with the largest echo energy as the frequency points for D2D communication between the two terminals.
[0021] Preferably, in step 5, after successfully obtaining the D2D connection establishment information from the broadcast, the two terminals begin a three-way handshake to establish a connection; the terminal then sets the N... sc,D Cyclic scanning on each frequency point, when the terminal is in residence time T dIf a broadcast signal is detected, the terminal will extend its dwell time on that frequency to decode the information in the short frame. If the correct destination ID is decoded, the terminal will continue to dwell until the source ID is decoded. The master terminal will call cyclically on each frequency. The signal structure of each call includes the destination ID and the source ID. The destination ID and the source ID occupy one short frame, and the destination ID is sent repeatedly for a duration longer than one scan cycle of the slave terminal. After each transmission, the master terminal will wait for the slave terminal's reply on that frequency. If no reply is received within a preset time, the master terminal will switch to the next frequency to make the call.
[0022] A computer system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When executed by the processor, the computer program implements the execution steps of a station or terminal in a station-assisted D2D communication method under a shortwave communication system.
[0023] A computer program product includes a computer program that, when executed by a processor, implements the execution steps of a station or terminal in a station-assisted D2D communication method under a shortwave communication system.
[0024] Beneficial Effects: This invention fundamentally solves the inherent defects of traditional shortwave communication by dynamically allocating D2D communication frequencies at stations. Addressing the low reliability of traditional D2D communication due to the time-varying characteristics of the ionosphere, it utilizes backscatter scanning of the ionospheric energy at the midpoint of the communication path to achieve adaptive frequency selection. Simultaneously, it avoids the dual resource consumption of station relay mode. On the one hand, it eliminates the decoding and remodulation operations required for "terminal-station-terminal" double-hop forwarding, compressing end-to-end latency; on the other hand, it releases station channel resources, avoiding link congestion and collision risks during concurrent communication by multiple terminals. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of relay communication at a shortwave system site.
[0026] Figure 2 This is a flowchart of a method according to an embodiment of the present invention.
[0027] Figure 3 This is a schematic diagram of the site broadcast signal structure in an embodiment of the present invention.
[0028] Figure 4 This is a schematic diagram of the terminal response signal structure in an embodiment of the present invention.
[0029] Figure 5 This is a schematic diagram of terminal time-division multiplexing response in an embodiment of the present invention.
[0030] Figure 6 This is a schematic diagram of the main terminal call signal structure in an embodiment of the present invention.
[0031] Figure 7 This is a schematic diagram of the structure of the reply signal from the terminal in an embodiment of the present invention.
[0032] Figure 8 This is a schematic diagram of the main terminal ACK signal structure in an embodiment of the present invention. Detailed Implementation
[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0034] like Figure 2 As shown in the figure, an embodiment of the present invention discloses a site-assisted D2D communication method in a shortwave communication system, comprising the following steps:
[0035] Step 1: The site and the terminal agree on a fixed frequency table, terminal ID, terminal serial number, and other information.
[0036] In this step, the number of selectable frequencies in the fixed frequency table is N. sc The number of terminals is N u And all terminals have a unique ID.
[0037] Step 2: All terminals scan the fixed frequency table; the station broadcasts the fixed frequency table to all terminals and then controls the corresponding frequency for the corresponding time period.
[0038] In this step, the terminal's scanning cycle is:
[0039] T s =N sc ×T d (1)
[0040] In equation (1), T d Let T be the dwell time of the terminal at each frequency. d If a broadcast signal is detected, the dwell time at that frequency will be extended to decode the information in the short frame. This time can be written as:
[0041] T dsf =2T sf (2)
[0042] In equation (2), T sf The duration of a short frame. If in T dsf Once the correct information is decoded, the terminal will continue to reside on that frequency to decode subsequent short frames until the source ID is decoded. The maximum residency time is T. wce If in T dsf The correct information was not found inside or in T wce If the source ID is not decoded, the terminal will switch to the next frequency and continue scanning.
[0043] A station broadcasts on a specific frequency. Its broadcast signal structure consists of broadcast characteristic signals, carried information, and a source ID, such as... Figure 3 As shown. To ensure that the terminal can receive the broadcast signal through scanning, the broadcast characteristic signal consists of multiple repeating short frames with a duration of T. sc (>T s The information consists of an integer number of short frames, which mainly contain the current D2D link information. The source ID occupies one short frame.
[0044] After a station transmits a broadcast frame on a certain frequency, it needs to stop transmitting and wait on that frequency to receive a response from the terminal. After the wait is over, the station will switch to the next frequency to broadcast.
[0045] Step 3: If the terminal in Step 2 receives the broadcast information from the station, the terminal reports its location information, status information, and requests to establish a D2D link; otherwise, repeat Step 2.
[0046] In this step, after the terminal correctly receives the broadcast from the site, it will proceed according to... Figure 4 The terminal responds to the signal structure shown. The destination ID and source ID occupy one short frame, while the information occupies multiple short frames. The information includes location information and status information, with three status states: idle, non-idle, and requesting D2D communication. In the idle state, the terminal does not actively request D2D communication with other terminals, but it can accept D2D communication requests from other terminals. In the non-idle state, the terminal rejects all D2D communication requests. When requesting D2D communication, the terminal needs to provide the terminal ID it wishes to communicate with.
[0047] All terminal responses use time-division multiplexing, such as Figure 5 As shown, the time after the station finishes sending the end flag is divided into different time slots, and each terminal sends data in a specific time slot according to its terminal sequence number. The duration T of each time slot is... sl Slightly greater than the total duration T of a single terminal response re This is to prevent collisions caused by factors such as spatial propagation time and transmit / receive switching time. Furthermore, during the first time slot, the station performs transmit / receive switching, and the terminal does not respond.
[0048] Step 4: The station receives a D2D link request from a terminal and checks whether the target terminal has reported the data. If the target terminal has reported the data, the station calculates the coordinates of the midpoint of the connection between the two terminals based on their location information, performs ionospheric monitoring based on these coordinates, and assigns one or more frequency points to the two terminals.
[0049] In this step, after receiving a response from the terminal, the station records the terminal's location and status. A cycle is defined as one broadcast from each terminal to all frequencies in a fixed frequency table. If the station does not receive a response from a terminal within a cycle, it automatically sets the terminal's status to non-idle. Upon receiving a D2D communication request from a terminal, if the target terminal's status is idle, the station calculates the coordinates of the midpoint of the line connecting the two terminals based on their location information. It then transmits a reference signal towards the midpoint to perform frequency scanning and receive the scattered echoes. Based on the energy of the scattered echoes, one or more suitable D2D communication frequencies can be selected. Simultaneously, the master and slave terminals for D2D link establishment are determined and written into the information section of the broadcast. Finally, the station sets the status of both terminals to non-idle.
[0050] Step 5: If a terminal receives a site broadcast in Step 4, it determines whether it has been designated as a D2D master or slave terminal. If designated as a D2D master terminal, it parses the D2D frequencies carried in the broadcast and performs loop calls on these frequencies; if designated as a D2D slave terminal, it parses the D2D frequencies carried in the broadcast and scans on these frequencies; otherwise, the terminal repeats Step 2.
[0051] In this step, after successfully obtaining the D2D connection establishment information from the broadcast, the two terminals begin a three-way handshake to establish a connection. The terminal then sets the N... sc,D The frequency points are scanned cyclically, with a scan period of:
[0052] T s,D =N sc,D ×T d (3)
[0053] When the terminal is in residence time T d If a broadcast signal is detected, the dwell time on that frequency will be extended to T. dsf Used to decode information in short frames. If in T... dsf Once the correct destination ID is decoded, the terminal will continue to reside until the source ID is decoded.
[0054] The master terminal makes calls cyclically on each frequency point. The signal structure of each call includes a destination ID and a source ID, such as... Figure 6 As shown. The destination ID and source ID occupy a short frame, and the destination ID needs to be sent repeatedly for a duration T. sc,D Greater than one scan cycle T from the terminal s,D After each transmission, the master terminal will wait for a reply from the slave terminal on that frequency. If in T... swt,D If no response is received, the call will be switched to the next frequency.
[0055] Step 6: If a call is received from the main terminal at step 5, then reply; otherwise, both terminals repeat step 5.
[0056] In this step, after receiving the call from the master terminal, the terminal then... Figure 7 The signal structure shown is used to respond. Then, the slave terminal waits for an ACK response from the master terminal; if in T... swt,D If no ACK signal is received, switch to the next frequency point to continue scanning.
[0057] Step 7: If the master terminal receives a reply from the slave terminal in step 6, it sends an ACK signal; otherwise, both terminals repeat step 5.
[0058] In this step, after the master terminal receives the reply from the slave terminal, it uses... Figure 8 The signal structure shown sends an ACK signal. Otherwise, the master terminal restarts the loop call.
[0059] Step 8: If the terminal receives an ACK signal from the master terminal at step 7, the D2D link establishment is successful; otherwise, the terminal repeats step 5. If the D2D link establishment fails to be completed within a certain time or the D2D communication ends, both terminals return to step 2.
[0060] In this step, if the chain establishment process is in T b If the connection is not established within the specified time, or if the two terminals have completed D2D communication, the two terminals will rescan the site broadcast and report the latest location and status.
[0061] This invention also discloses a computer system, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the execution steps of the station or terminal in the station-assisted D2D communication method under a shortwave communication system.
[0062] This invention also discloses a computer program product, including a computer program that, when executed by a processor, implements the execution steps of a station or terminal in a station-assisted D2D communication method under a shortwave communication system.
Claims
1. A site-assisted D2D communication method in a shortwave communication system, characterized in that, Includes the following steps: Step 1: The site and the terminal agree on a fixed frequency table, terminal ID, and terminal serial number; Step 2: All terminals scan the fixed frequency table; the station broadcasts to all terminals using the fixed frequency table. Step 3: If the terminal receives broadcast information from the station, it reports its location information, status information, and requests to establish a D2D link. Step 4: The site receives a D2D link request from a terminal and checks whether the target terminal has reported it. If the target terminal has reported, the station calculates the coordinates of the midpoint of the line connecting the two terminals based on their location information, performs ionospheric monitoring based on these coordinates, evaluates each frequency point, and assigns one or more frequency points to the two terminals. Step 5: If the station in Step 4 broadcasts that the requested link is feasible, the terminal scans the frequency points allocated by the station, and the master terminal makes cyclic calls on these frequency points. Otherwise, the terminal repeats step 2; Step 6: If a call is received from the main terminal at step 5, then reply; otherwise, both terminals repeat step 5. Step 7: If the master terminal receives a reply from the slave terminal in step 6, it sends an ACK signal; otherwise, both terminals repeat step 5. Step 8: If the terminal receives the ACK signal from the master terminal at step 7, the D2D link establishment is successful; otherwise, the terminal repeats step 5. If the D2D link establishment is not completed within the preset time or the D2D communication ends, both terminals return to step 2.
2. The site-assisted D2D communication method in a shortwave communication system according to claim 1, characterized in that, In step 2, the terminal's scanning period is T. s =N sc ×T d , where N sc T represents the number of selectable frequencies in the fixed frequency table. d Let T be the dwell time of the terminal at each frequency point. d If a broadcast signal is detected, the dwell time on that frequency will be extended to decode the information in the short frame; if the extended dwell time T... dsf =2T sf Once the correct information is decoded, the terminal will continue to reside on that frequency to decode subsequent short frames until the source ID, T, is decoded. sf For the duration of a short frame; if in T dsf The correct information was not found or the longest dwell time T was not found. wce If the source ID is not decoded, the terminal switches to the next frequency and continues scanning.
3. The site-assisted D2D communication method in a shortwave communication system according to claim 2, characterized in that, In step 2, the station broadcasts on a frequency. The broadcast signal structure consists of a broadcast feature signal, carried information, and a source ID. The broadcast feature signal consists of multiple repeating short frames with a duration T. sc The scanning cycle is longer than that of the terminal, and the information it carries consists of an integer number of short frames, including the current D2D link information; the source ID occupies one short frame.
4. The site-assisted D2D communication method in a shortwave communication system according to claim 1, characterized in that, In step 3, after the terminal correctly receives the broadcast from the station, the reply signal structure consists of the destination ID, the information carried, and the source ID. The destination ID and source ID occupy one short frame, while the information carried occupies multiple short frames. The information includes location information and status information, among which the status information includes three types: idle, non-idle, and requesting D2D communication.
5. The site-assisted D2D communication method in a shortwave communication system according to claim 1, characterized in that, In step 3, all terminals use time-division multiplexing to reply, dividing the time after the station finishes sending the end flag into different time slots. Each terminal sends according to its priority number in the corresponding time slot. In the first time slot, the station performs a send / receive switch, and the terminal does not reply.
6. The site-assisted D2D communication method in a shortwave communication system according to claim 1, characterized in that, In step 4, after receiving a response from the terminal, the station records the terminal's location and status. A cycle is defined as one broadcast from the terminal to all frequencies in the fixed frequency table. If the station does not receive a response from a terminal within a cycle, its status is automatically set to non-idle. Upon receiving a D2D communication request from a terminal, if the target terminal is idle, the station calculates the coordinates of the midpoint of the connection between the two terminals based on their location information. Then, based on these coordinates, it performs ionospheric monitoring, selects one or more frequencies, and determines the master and slave terminals for D2D link establishment. These are then written into the information portion of the broadcast. Finally, the station sets the status of both terminals to non-idle.
7. A site-assisted D2D communication method for a shortwave communication system according to claim 1, characterized in that, In step 4, after the station obtains the positions of the two terminals, it calculates the coordinates of the midpoint M. Then, the station controls the beam to point to point M and steps to detect and record the echo energy in the 3MHz-30MHz frequency band. One or more frequency points with the largest echo energy are selected as the frequency points for D2D communication between the two terminals.
8. The site-assisted D2D communication method in a shortwave communication system according to claim 1, characterized in that, In step 5, after successfully obtaining the D2D connection establishment information from the broadcast, the two terminals begin a three-way handshake to establish a connection; the terminal then sets the N... sc,D Cyclic scanning on each frequency point, when the terminal is in residence time T d If a broadcast signal is detected, the terminal will extend its dwell time on that frequency to decode the information in the short frame. If the correct destination ID is decoded, the terminal will continue to dwell until the source ID is decoded. The master terminal will call cyclically on each frequency. The signal structure of each call includes the destination ID and the source ID. The destination ID and the source ID occupy one short frame, and the destination ID is sent repeatedly for a duration longer than one scan cycle of the slave terminal. After each transmission, the master terminal will wait for the slave terminal's reply on that frequency. If no reply is received within a preset time, the master terminal will switch to the next frequency to make the call.
9. A computer system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by the processor, it implements the execution steps of the station or terminal of the station-assisted D2D communication method under a shortwave communication system according to any one of claims 1-8.
10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the execution steps of the station or terminal of the station-assisted D2D communication method under a shortwave communication system as described in any one of claims 1-8.