CN113660027B - Dynamic access method of low-orbit satellite in VDES system - Google Patents
Dynamic access method of low-orbit satellite in VDES system Download PDFInfo
- Publication number
- CN113660027B CN113660027B CN202110899180.1A CN202110899180A CN113660027B CN 113660027 B CN113660027 B CN 113660027B CN 202110899180 A CN202110899180 A CN 202110899180A CN 113660027 B CN113660027 B CN 113660027B
- Authority
- CN
- China
- Prior art keywords
- low
- orbit satellite
- ship
- phi
- frequency shift
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18519—Operations control, administration or maintenance
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Radio Relay Systems (AREA)
Abstract
The invention belongs to the technical field of wireless communication, and particularly relates to a dynamic access method of a low-orbit satellite in a VDES system, which comprises the following steps: sequencing and numbering the ships according to the Doppler frequency shift of the uplink signals; and sequentially carrying out uplink dynamic access on the low-orbit satellite on the ship according to the serial number of the ship. Compared with the existing direct competition access method, the invention adds the sorting of the ships according to the Doppler frequency shift values, and the ships with small Doppler frequency shift values are accessed according to the sorting, so that the Doppler frequency shift of the system can be reduced; the invention also increases the dynamic adjustment that when the ship is in the coverage range of a plurality of low-orbit satellites, one low-orbit satellite fails to be accessed and is adjusted to another low-orbit satellite for access, thereby fully utilizing the idle channel resources of the low-orbit satellites. Therefore, the method disclosed by the invention can fully utilize the idle channel resources of the low-orbit satellite and effectively reduce the Doppler frequency shift of the system.
Description
Technical Field
The invention belongs to the technical field of wireless communication, and particularly relates to a dynamic access method of a low-orbit satellite in a VDES system.
Background
Maritime communication is a requirement for marine navigation of ships and also a requirement for ensuring the safety of the marine navigation. The original maritime communication mainly depends on an Automatic Identification System (AIS) of a ship to realize information transmission among the ship, the coast and the satellite. With the increasing number of ships and diversification of information demands, stronger data exchange capacity is needed among ships, coasts and satellites to exchange richer information, such as navigation, collision avoidance, weather, hydrology, risk warning, search, rescue and rescue information and the like. The original AIS System has not been able to meet the actual demand, so the International Association of navigation systems (IALA) proposed a very high frequency Data Exchange System (VDES), and the VDES System comprehensively promotes the Data transmission capability among ships, coasts, and satellites by introducing Application Specific Message information (ASM) and very high frequency Data Exchange (VDE).
With the introduction of integrated networks of "air-space-sea", the development of "air" in VDES systems is partially starting towards a stereoscopic network composed of medium and low orbit satellites and geosynchronous orbit satellites, wherein low orbit satellite communication has the advantages of shorter transmission delay, smaller path loss, easier avoidance of congestion of synchronous orbits, easier realization of global coverage, and so on, and thus receives a great deal of attention, for example, documents "VDES-based air-space-sea communication network architecture and key technology" (author huxu, mobile communication, 5 th in 2019, pages 2 to 8) and documents "satellite communication and 5G (up)" (author chu 26107, digital communication world, 9 months in 2020, pages 1 to 5). However, the relative motion speed between the low-orbit satellite and the earth is high, so the doppler shift effect between the low-orbit satellite and the marine vessel is serious, and the transmission quality of signals is seriously influenced. In addition, a ship may be in the coverage of multiple low-orbit satellites at the same time, so how to select proper low-orbit satellite access is a key problem to be solved.
Summarizing the existing research findings, in order to reduce the doppler shift effect, the ships in the existing documents adopt the direct competition access method based on the minimum doppler shift when selecting the low orbit satellite access, for example, the documents "VDES satellite constellation design and communication key technology research" (the authors have great profits, university of electronic technology, academic paper, 2017, 03 month) and the documents "the architecture and key technology of the space, ground and sea communication network based on VDES" (the authors have avail, mobile communication, 2019, 5 th, pages 2-8) adopt the direct competition access method. The direct competition access method gives up access when the minimum Doppler frequency shift low orbit satellite of the ship has no idle channel, does not consider the dynamic adjustment of the access when the ship is in the coverage range of a plurality of low orbit satellites, and therefore can not fully utilize the idle channel resources, and does not consider the access sequencing according to the Doppler frequency shift value, and therefore can not effectively reduce the Doppler frequency shift of the system. Therefore, a dynamic access method for low-orbit satellites, which can fully utilize the idle channel resources and effectively reduce the doppler frequency shift of the system, needs to be found.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a dynamic access method of a low-orbit satellite in a VDES system, which can fully utilize idle channel resources and effectively reduce the Doppler frequency shift of the system.
The scheme for solving the technical problems is as follows:
a dynamic access method for a low orbit satellite in a VDES system, the method comprising the steps of:
the method comprises the following steps: sorting and numbering ships according to Doppler frequency shift of uplink signals
There are N vessels, each of which is at least phi 1 And phi 2 One of the two low orbit satellites is in the coverage range, and the N ships simultaneously send uplink access request signals, wherein the low orbit satellite phi 1 And phi 2 Separately estimating the Doppler shift of the uplink signal of each vessel, wherein the ith vessel is relative to the low-orbit satellite phi 1 And phi 2 Respectively, as the Doppler shift of the uplink signal
And
wherein i belongs to {1,2, \8230;, N };
if the ith ship is only in the low orbit satellite phi 1 Or phi 2 Within the coverage of
Or
First, find out the relative phi of each ship to the low orbit satellite 1 And phi 2 I.e. the ith vessel relative to the low earth orbit satellite phi 1 And phi 2 Has a minimum Doppler shift of
Maximum Doppler shift of
Wherein min i ∈{φ 1 ，φ 2 Is the minimum Doppler shift low orbit satellite, epc, of vessel i i ∈{φ 1 ，φ 2 Is the maximum Doppler shift low-orbit satellite of ship i, an
Then sorting the minimum Doppler frequency shift values of the N ships from small to large, and numbering the sorted ships as l in sequence 1 ，l 2 ，…，l j ，…，l N I.e. by
Wherein j belongs to {1,2, \8230;, N }, lj belongs to {1,2, \8230;, N };
step two: and sequentially carrying out uplink dynamic access on the low-orbit satellite on the ship according to the serial number of the ship, wherein the dynamic access algorithm of the low-orbit satellite is as follows:
1) Let j =1;
2) For ship q = l j Performing uplink dynamic access of the low-earth orbit satellite:
3) Minimum Doppler frequency shift low-orbit satellite min for searching ship q q Whether there is a free channel;
31 If low earth orbit satellite min q If the idle channel exists, jumping to the step 5);
32 If low earth orbit satellite min q If no idle channel exists, judging that the ship q is relative to the low orbit satellite epc q Doppler shift of (2)
Whether it is equal to ∞;
321 If)
If the value is equal to infinity, jumping to the step 4);
322 If)
Searching the maximum Doppler frequency shift low-orbit satellite epc of the ship q not equal to infinity q Whether there is a free channel;
3221 If low orbit satellite epc q Jumping to step 4) if no idle channel exists;
3222 If low orbit satellite epc q Jumping to step 5) if an idle channel exists;
4) Putting the access request message of the ship q, waiting for the next frame to arrive, searching for the idle channel access for the ship q, and then jumping to the step 6);
5) Accessing the ship q into the idle channel, and then jumping to the step 6);
6) j = j +1, and judging whether j is less than or equal to N;
61 If j is less than or equal to N, returning to the step 2), and q = l for the next ship j Performing uplink dynamic access of the low-orbit satellite;
62 If j > N, the dynamic access of the low-orbit satellite has been completed for all ships, and the algorithm is ended.
Compared with the prior art, the invention has the following beneficial effects:
compared with the existing direct competition access method of the low orbit satellite, the dynamic access method of the low orbit satellite in the VDES system has the advantages that ships are sequenced according to the Doppler frequency shift value of an uplink access request signal, and then the ships with small Doppler frequency shift values are accessed according to the sequencing, so that the Doppler frequency shift of the system can be reduced, and the communication quality is improved. And the invention also increases the dynamic adjustment that when the ship is in the coverage area of a plurality of low-orbit satellites, one low-orbit satellite fails to access and is adjusted to another low-orbit satellite for access, so that the idle channel resources of the low-orbit satellite can be fully utilized, the success rate of the access of the low-orbit satellite can be improved, the timeliness of the communication between the ship and the low-orbit satellite is ensured, and the invention has a particularly important significance on the navigation safety of the ship.
Drawings
FIG. 1 is a block diagram illustrating the steps of a dynamic access method for a low-earth orbit satellite in a VDES system according to the present invention;
FIG. 2 is a schematic diagram of a system model of a dynamic access method for low-earth orbit satellites in a VDES system according to the present invention;
FIG. 3 is a block diagram of a dynamic access algorithm for a low-earth orbit satellite in a dynamic access method for a low-earth orbit satellite in a VDES system disclosed in the present invention;
FIG. 4 is a diagram showing simulation results of average Doppler shift of a low-earth orbit satellite in a VDES system according to the present invention;
Detailed Description
The invention will be further explained with reference to the drawings.
Example 1
As shown in fig. 1 to 3, the present invention discloses a dynamic access method for a low-orbit satellite in a VDES system, which comprises the following steps:
the method comprises the following steps: sorting and numbering ships according to Doppler frequency shift of uplink signals
There are N vessels, see figure 2, where each vessel is located at least at phi 1 And phi 2 One of the two low orbit satellites is in the coverage range, and the N ships simultaneously send uplink access request signals, wherein the low orbit satellite phi 1 And phi 2 Separately estimating the Doppler shift of the uplink signal of each ship, wherein the ith ship is relative to the low-orbit satellite phi 1 And phi 2 Respectively, are recorded as the Doppler frequency shift of the uplink signal
And
wherein i belongs to {1,2, \8230;, N };
if the ith ship is only in the low orbit satellite phi 1 Or phi 2 Within the coverage of (2), then
Or
First, find out the relative phi of each ship to the low orbit satellite 1 And phi 2 I.e. the ith vessel relative to the low orbit satellite phi 1 And phi 2 Is the most important ofA small Doppler shift of
Maximum Doppler shift of
Wherein min i ∈{φ 1 ，φ 2 Is the minimum Doppler shift low orbit satellite, epc, of vessel i i ∈{φ 1 ，φ 2 Is the maximum Doppler shift low-orbit satellite of the ship i, and
then sorting the minimum Doppler frequency shift values of the N ships from small to large, and numbering the sorted ships as l in sequence 1 ，l 2 ，…，l j ，…，l N I.e. by
Where j ∈ {1,2, \8230;, N }, l ∈ [ ] j ∈{1，2，…，N}；
Step two: according to the serial number of the ship, the ship is sequentially subjected to uplink dynamic access of the low-orbit satellite, and fig. 3 is a flow chart of a dynamic access algorithm of the low-orbit satellite, which is specifically described as follows:
1) Let j =1;
2) For ship q = l j And performing uplink dynamic access of the low-orbit satellite:
3) Minimum Doppler frequency shift low-orbit satellite min for searching ship q q Whether there is a free channel;
31 If low earth orbit satellite min q Jumping to step 5) if an idle channel exists;
32 If low orbit satellite min q If no idle channel exists, judging that the ship q is relative to the low orbit satellite epc q Doppler shift of (2)
Whether it is equal to ∞;
321 If) if
If the value is equal to infinity, jumping to the step 4);
322 If)
Not equal to infinity, searching the maximum Doppler frequency shift low orbit satellite epc of the ship q q Whether there is a free channel;
3221 If low orbit satellite epc q Jumping to step 4) if no idle channel exists;
3222 If low orbit satellite epc) q Jumping to step 5) if an idle channel exists;
4) Laying aside the access request message of the ship q, waiting for the next frame to arrive, searching for an idle channel for the ship q to access, and then jumping to the step 6);
5) Accessing a ship q into the idle channel, and then jumping to the step 6);
6) j = j +1, and j is judged whether less than or equal to N;
61 If j is less than or equal to N, returning to the step 2), and q = l for the next ship j Performing uplink dynamic access of the low-orbit satellite;
62 If j > N, the dynamic access of the low-orbit satellite has been completed for all ships, and the algorithm is ended.
Example 2 (Experimental example)
The following is a simulation experiment performed according to the dynamic access method of low-orbit satellites in the VDES system disclosed in the present invention to illustrate the feasibility and effectiveness of the method of the present invention.
During simulation, the radius of the earth is 6370km, the orbit heights of 2 low-orbit satellites are 780km, the frequency of an uplink signal is 160MHz, continuous 10 minutes are selected as simulation time, the total number of idle channels of the 2 low-orbit satellites is 100, the idle channels are randomly distributed on the 2 low-orbit satellites, and the ship is uniformly distributed in the coverage range of the 2 low-orbit satellites. And if the ship is not successfully accessed in the simulation, calculating according to the maximum Doppler frequency shift of 40 KHz.
Fig. 4 is a simulation result diagram, in which "direct contention access" is the low earth orbit satellite access method in the prior art, and "dynamic access" is the dynamic access method of the low earth orbit satellite disclosed in the present invention.
In fig. 4, the abscissa represents the number N of the vessels, and the ordinate represents the average doppler shift of all the vessels. As can be seen from fig. 4, as the number of ships increases, the average doppler frequency shift of the "direct competition access" and the "dynamic access" increases, because as the number of ships increases, the number of ships that cannot be successfully accessed increases, so the average doppler frequency shift increases. The dynamic access disclosed by the invention is obviously superior to direct competitive access, and the advantage of the dynamic access is more obvious when the number N of ships is larger. The reason is that compared with the direct competition access, the dynamic access increases the sorting of the ships according to the Doppler frequency shift values, and the ships with small Doppler frequency shift values are accessed firstly according to the sorting, so that the Doppler frequency shift of the system can be effectively reduced.
In summary, compared with the existing direct contention access method, the dynamic access method for the low orbit satellite in the VDES system disclosed by the present invention can fully utilize the idle channel resources of the low orbit satellite and effectively reduce the doppler frequency shift of the system.
Claims (1)
1. A dynamic access method for a low orbit satellite in a VDES system, the method comprising the steps of:
the method comprises the following steps: sorting and numbering ships according to Doppler frequency shift of uplink signals
There are N vessels, each of which is at least phi 1 And phi 2 One of the two low orbit satellites is in the coverage range, and the N ships simultaneously send uplink access request signals, wherein the low orbit satellite phi 1 And phi 2 Separately estimating the Doppler shift of the uplink signal of each vessel, wherein the ith vessel is relative to the low-orbit satellite phi 1 And phi 2 Respectively, are recorded as the Doppler frequency shift of the uplink signal
And
wherein i belongs to {1,2, \8230;, N };
if the ith ship is only in the low orbit satellite phi 1 Or phi 2 Within the coverage of
Or
First, find out the relative phi of each ship to the low orbit satellite 1 And phi 2 I.e. the ith vessel relative to the low earth orbit satellite phi 1 And phi 2 Has a minimum Doppler shift of
Maximum Doppler shift of
Wherein min i ∈{φ 1 ,φ 2 Is the minimum Doppler shift low orbit satellite, epc, of vessel i i ∈{φ 1 ,φ 2 Is the maximum Doppler shift low-orbit satellite of the ship i, and
then sorting the minimum Doppler frequency shift values of the N ships from small to large, and numbering the sorted ships as l in sequence 1 ,l 2 ,…,l j ,…,l N I.e. by
Wherein j ∈ {1,2, \8230;, N }, l j ∈{l 1 ,l 2 ,…,l N }；
Step two: and sequentially carrying out uplink dynamic access on the low-orbit satellite on the ship according to the serial number of the ship, wherein the dynamic access algorithm of the low-orbit satellite is as follows:
1) Let j =1;
2) For ship q = l j And performing uplink dynamic access of the low-orbit satellite:
3) Minimum Doppler frequency shift low-orbit satellite min for searching ship q q Whether there is a free channel;
31 If low earth orbit satellite min q If the idle channel exists, jumping to the step 5);
32 If low earth orbit satellite min q If no idle channel exists, judging that the ship q is opposite to the low orbit satellite epc q Doppler shift of
Whether it is equal to ∞;
321 If)
If the value is equal to infinity, jumping to the step 4);
322 If)
Searching the maximum Doppler frequency shift low-orbit satellite epc of the ship q not equal to infinity q Whether there is a free channel;
3221 If low orbit satellite epc q Jumping to step 4) if no idle channel exists;
3222 If low orbit satellite epc q Jumping to step 5) if an idle channel exists;
4) Laying aside the access request message of the ship q, waiting for the next frame to arrive, searching for an idle channel for the ship q to access, and then jumping to the step 6);
5) Accessing the ship q into the idle channel, and then jumping to the step 6);
6) j = j +1, and judging whether j is less than or equal to N;
61 ) if j is less than or equal to N, returning to step 2), and q = l for the next ship j Uplink dynamic connection of low earth orbit satelliteEntering;
62 If j > N, the dynamic access of the low-orbit satellite has been completed for all ships, and the algorithm is ended.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110899180.1A CN113660027B (en) | 2021-08-05 | 2021-08-05 | Dynamic access method of low-orbit satellite in VDES system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110899180.1A CN113660027B (en) | 2021-08-05 | 2021-08-05 | Dynamic access method of low-orbit satellite in VDES system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113660027A CN113660027A (en) | 2021-11-16 |
| CN113660027B true CN113660027B (en) | 2023-02-28 |
Family
ID=78490436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110899180.1A Active CN113660027B (en) | 2021-08-05 | 2021-08-05 | Dynamic access method of low-orbit satellite in VDES system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113660027B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6058306A (en) * | 1998-11-02 | 2000-05-02 | Hughes Electronics Corporation | Compensation of dynamic doppler frequency of large range in satellite communication systems |
| CN111372320A (en) * | 2020-04-08 | 2020-07-03 | 成都爱科特科技发展有限公司 | Ship VDES communication system and method for channel scheduling |
| CN111385013A (en) * | 2018-12-29 | 2020-07-07 | 华为技术有限公司 | Method and device for broadcasting data |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10884138B2 (en) * | 2018-06-21 | 2021-01-05 | Eagle Technology, Llc | Satellite automatic identification system (AIS) for tracking a plurality of maritime vessels and related methods |
-
2021
- 2021-08-05 CN CN202110899180.1A patent/CN113660027B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6058306A (en) * | 1998-11-02 | 2000-05-02 | Hughes Electronics Corporation | Compensation of dynamic doppler frequency of large range in satellite communication systems |
| CN111385013A (en) * | 2018-12-29 | 2020-07-07 | 华为技术有限公司 | Method and device for broadcasting data |
| CN111372320A (en) * | 2020-04-08 | 2020-07-03 | 成都爱科特科技发展有限公司 | Ship VDES communication system and method for channel scheduling |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113660027A (en) | 2021-11-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Eriksen et al. | Maritime traffic monitoring using a space-based AIS receiver | |
| CN111565465B (en) | Scheduling and distributing method for satellite-ground channel of VDES (virtual disk evolution system) | |
| CN211352458U (en) | Ship VDES communication system for channel scheduling | |
| US20210105063A1 (en) | Location-based wireless communication access over a satellite communication network | |
| CN111294110B (en) | Beidou global short message satellite selection method based on satellite coverage service volume density | |
| CN116403441B (en) | Scheduling method, device, equipment and medium for ship arrival and departure | |
| CN113660027B (en) | Dynamic access method of low-orbit satellite in VDES system | |
| CN111372320A (en) | Ship VDES communication system and method for channel scheduling | |
| CN111210665A (en) | Satellite-borne AIS time slot collision signal separation method based on single antenna | |
| CN113891470A (en) | Dynamic frequency reuse method between self-organizing cells of VDES system | |
| CN108924903B (en) | MAC layer selective access method based on signal cross-correlation | |
| CN110300388B (en) | Power control method and device of sea area communication system | |
| Lin et al. | Next generation marine wireless communication networks | |
| CN115827185B (en) | Method, storage medium and equipment for combining 6G air base station with Beidou air obstacle avoidance | |
| CN114070538A (en) | Dynamic pilot frequency allocation method in ship-shore VDE communication | |
| Zhang et al. | An improved MAC protocol design in VHF data exchange system (VDES) for Internet of vessels | |
| Namgung | Spectrum requirements for control and non-payload communication of maritime autonomous surface ship | |
| Hasegawa et al. | Transmission evaluation of Ship-borne Automatic Identification System (AIS) in congested waterways | |
| Hu et al. | A collision feedback based multiple access control protocol for very high frequency data exchange system in E-navigation | |
| WO2010106280A1 (en) | Payload for a satellite with ais, and corresponding method | |
| CN111698024B (en) | Ship satellite vsat video bandwidth allocation information transmission system and method | |
| CN114827132B (en) | Ship traffic file transmission control method, system, device and storage medium | |
| CN113115455B (en) | VDES system self-adaptive channel selection method capable of reducing time slot collision probability | |
| CN117279072B (en) | Terminal access method and device | |
| CN117880331B (en) | Block chain data sharing method and device for ocean satellite Internet of things |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: A Dynamic Access Method for Low Earth Orbit Satellites in VDES System Effective date of registration: 20230724 Granted publication date: 20230228 Pledgee: China Construction Bank Corporation Weishan sub branch Pledgor: Shandong Xingtong Easy Aviation Communication Technology Co.,Ltd. Registration number: Y2023980049531 |