CN112838890A - Satellite communication system with cooperative spectrum sensing and communication - Google Patents
Satellite communication system with cooperative spectrum sensing and communication Download PDFInfo
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- CN112838890A CN112838890A CN202110174130.7A CN202110174130A CN112838890A CN 112838890 A CN112838890 A CN 112838890A CN 202110174130 A CN202110174130 A CN 202110174130A CN 112838890 A CN112838890 A CN 112838890A
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- 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
- H04B7/18513—Transmission in a satellite or space-based system
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
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- 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
Abstract
One embodiment of the invention discloses a satellite communication system with cooperative spectrum sensing and communication, which comprises: the system comprises a spectrum sensing antenna, spectrum sensing processing equipment, a service antenna, service processing equipment and inter-satellite transmission equipment, wherein the spectrum sensing antenna is used for receiving and frequency converting a radiation signal and outputting a first output signal; the frequency spectrum sensing processing equipment is used for processing the first output signal and transmitting the frequency band and the position of the first output signal to the service processing equipment and the inter-satellite transmission equipment; the service processing equipment rejects the corresponding frequency band in a subcarrier deleting mode when frequency band resources are allocated according to the frequency band and the position of the first output signal, and a generated second output signal is transmitted to a service antenna; the service antenna does not point to a service area corresponding to a wave position related to the first output signal according to a control instruction of the service processing equipment, and the second output signal is amplified and then radiated to a space; the inter-satellite transmission device informs the adjacent satellite of the frequency band and the position information of the first output signal.
Description
Technical Field
The invention relates to the technical field of satellite communication, in particular to a satellite communication system based on frequency spectrum sensing and communication coordination.
Background
In a low-earth-orbit satellite communication system, in order to enhance satellite-ground fusion degree, one method is to adopt a lower frequency band and share the same frequency with other systems on the ground to achieve the aim of satellite-satellite communication broadband hand-held communication. One of the methods is to use a frequency band of a ground radar to perform low earth orbit satellite communication. On the basis of obtaining the position and the frequency band of the ground radar based on the spectrum sensing technology, a certain space isolation degree is provided by adopting a space evasion method, the isolation degree is further improved by adopting a frequency evasion method, and various requirements of sharing the frequency band with the radar can be met.
The traditional satellite communication system adopting fixed beams can only adopt a beam closing mode to provide space isolation, and large-area users have no signals. By adopting the phased array beam hopping technology, the beam angle is small, the coverage range is small, the interference range is small, and the signal-free range of a user caused by space isolation can be greatly reduced. Under the condition that the satellite processing technology and the satellite spectrum sensing technology are more and more mature, the beam hopping technology can adjust beam pointing direction in real time and plan a service area in real time according to the spectrum sensing condition, and the space evasion method on the basis has small interference on the ground and low influence on the system efficiency.
In the traditional communication system adopting a single carrier or a plurality of wide-band subcarriers, when a scene needing frequency avoidance is encountered, a wider bandwidth needs to be closed, and the single-satellite available frequency spectrum is directly narrowed. On the basis of wide application of the OFDM technology, the OFDM flexible subcarrier allocation method is utilized, flexible and continuous adjustment can be performed according to the actual working frequency band of the ground radar, and the frequency avoidance method on the basis is high in adaptability and low in influence on system efficiency.
Disclosure of Invention
The invention aims to provide a satellite communication system with cooperative spectrum sensing and communication, so as to realize the frequency sharing of a low-earth-orbit satellite communication downlink frequency band and a radar, achieve higher isolation and expand the available frequency of low-earth-orbit satellite communication.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a satellite communication system with cooperative spectrum sensing and communication, which comprises: a spectrum sensing antenna, a spectrum sensing processing device, a service antenna, a service processing device and an inter-satellite transmission device,
wherein the content of the first and second substances,
the spectrum sensing antenna is used for receiving and frequency converting the radiation signal and outputting a first output signal to the spectrum sensing processing equipment;
the frequency spectrum sensing processing equipment is used for processing the received first output signal and transmitting the frequency band and position information of the first output signal to the service processing equipment and the inter-satellite transmission equipment;
the service processing equipment plans a wave position related to the first output signal not to provide service according to the frequency band and the position of the first output signal, and rejects the corresponding frequency band in a subcarrier deleting mode when frequency band resources are allocated, and transmits a generated second output signal to a service antenna;
the service antenna does not point to a service area corresponding to a wave position related to the first output signal according to a control instruction of the service processing equipment, and a second output signal transmitted by the service processing equipment is amplified by an amplifier and then radiated to a space;
and the inter-satellite transmission equipment informs the adjacent satellite of the position and the frequency band of the first output signal.
In a specific embodiment, the spectrum sensing antenna covers a communication service frequency band of the system, and adopts an antenna form with adjustable beam direction.
In a specific embodiment, the spectrum sensing processing device processes the received first output signal, and the processing includes identifying a frequency band in which the first output signal is located, and estimating a direction from which the first output signal originates to obtain a location thereof.
In a specific embodiment, the time for completing spectrum sensing of 1 wave position is dT, during the spectrum sensing, the satellite does not transmit a same-frequency signal, only the spectrum of 1 wave position is sensed in every dT time, dT is far greater than dT, during the rest dT-dT times, the satellite normally communicates, the total time for sensing all the wave positions is dT × N, which is called a sensing period, and N is the wave position number required by all sensing of a coverage area.
In one embodiment, the amplifier meets linearity requirements to ensure that the signal power generated by the amplifier in the frequency band to be avoided does not exceed a standard.
In one embodiment, the G/T value of the spectrum sensing antenna meets the requirement of detecting the side lobe of the ground radiation source, and the positioning error value is equivalent to the size of the communication beam coverage area.
In a specific embodiment, the ground projection range required to be sensed by the spectrum sensing antenna is larger than the communication coverage range, the coverage radius of the former is the sum of the coverage radius of the latter and ddr, and ddr is the sum of the range of the extra coverage of the side lobe when the satellite points to the most marginal wave position and the distance of time flight consumed by the satellite at all positions in the spectrum sensing coverage area.
In a specific embodiment, the service processing device plans a service area and an available frequency band according to the frequency band and the location information obtained in the last sensing period, and the frequency band and the location information obtained in the current sensing period are used in the next sensing period.
The invention has the following beneficial effects:
the invention can realize the frequency sharing of the low-earth-orbit satellite communication downlink frequency band and the radar, achieve higher isolation, expand the available frequency of the low-earth-orbit satellite communication, and simultaneously have low influence on the time efficiency and the spectral efficiency of a communication system and small influence on a service area.
Drawings
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 diagram of a satellite communication system with spectrum sensing and communication coordination according to an embodiment of the present invention.
Detailed Description
In order to make the 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.
The invention provides a satellite communication system with cooperative spectrum sensing and communication, as shown in fig. 1, comprising: a spectrum sensing antenna, a spectrum sensing processing device, a service antenna, a service processing device and an inter-satellite transmission device,
wherein the content of the first and second substances,
the spectrum sensing antenna is used for receiving and frequency converting the radiation signal and outputting a first output signal to the spectrum sensing processing equipment;
the frequency spectrum sensing processing equipment is used for processing the received first output signal and transmitting the frequency band and position information of the first output signal to the service processing equipment and the inter-satellite transmission equipment;
and the service processing equipment plans the wave position related to the first output signal not to provide service according to the frequency band and the position of the first output signal, eliminates the frequency band corresponding to the first output signal in a subcarrier deleting mode when frequency band resources are distributed, and transmits the generated second output signal to a service antenna so as to achieve the purpose of frequency avoidance.
The service antenna does not point to a service area corresponding to a wave position related to the first output signal according to a control instruction of the service processing equipment, and a second output signal transmitted by the service processing equipment is amplified by an amplifier and then radiated to a space;
the inter-satellite transmission equipment informs the position and the frequency band of the first output signal to the adjacent satellite, the adjacent satellite naturally has space isolation due to not covering the radiation source position, whether frequency isolation is needed or not is determined according to the total isolation requirement, the corresponding subcarrier is removed, and the isolation is further improved.
In one embodiment, the range of the nearby satellite is a vertically upward conical space range with the ground radiation source as the vertex, which is calculated according to the avoidance requirement.
After the satellite senses a wave position needing to be avoided, the satellite needs to inform surrounding satellites except for avoiding, and the surrounding satellites need to be avoided and communicate through inter-satellite links.
In a specific embodiment, the spectrum sensing antenna covers a communication service frequency band of the system, and adopts an antenna form with adjustable beam direction.
In a specific embodiment, the spectrum sensing processing device processes the received first output signal, and the processing includes identifying a frequency band in which the first output signal is located, and estimating a direction from which the first output signal originates to obtain a location thereof.
In a specific embodiment, the time for completing spectrum sensing of 1 wave position is dT, the millisecond level is lower, during the spectrum sensing, the satellite does not transmit a same frequency signal, only the spectrum of 1 wave position is sensed in every dT time, dT is far greater than dT, during the rest dT-dT times, the satellite normally communicates, the total time for sensing all the wave positions is dT N, which is called a sensing period, and N is the wave position number required by all the sensing of a coverage area.
In one embodiment, the amplifier meets linearity requirements to ensure that the signal power generated by the amplifier in the frequency band to be avoided does not exceed a standard.
In a specific embodiment, the G/T value of the spectrum sensing antenna meets the requirement of detecting the side lobe of the ground radiation source, the positioning error value is equivalent to the size of the communication beam coverage area, and the smaller the value, the better the value without adding extra cost, wherein the G/T value is the ratio of the gain of the receiving antenna to the noise.
In a specific embodiment, the ground projection range required to be sensed by the spectrum sensing antenna is larger than the communication coverage range, the coverage radius of the former is the sum of the coverage radius of the latter and ddr, and ddr is the sum of the range of the extra coverage of the side lobe when the satellite points to the most marginal wave position and the distance of time flight consumed by the satellite at all positions in the spectrum sensing coverage area.
In a specific embodiment, the service processing device plans a service area and an available frequency band according to the frequency band and the location information obtained in the last sensing period, the frequency band and the location information obtained in the current sensing period are used in the next sensing period, and the available frequency band is the frequency band from which the subcarriers are removed.
For the clarity of the present invention, the example of the isolation requirement of 50dB is illustrated:
the spectrum sensing antenna covers all communication service frequency bands of the system, a sensing area in a wave beam adjustable antenna form is divided into 36 wave bits, the receiving and frequency conversion of radiation signals are completed, and a first output signal is output to spectrum sensing processing equipment; the G/T value of the antenna meets the requirement of detecting and receiving the side lobe of the ground radiation source, and the positioning error is not more than 30 km.
The spectrum sensing antenna of the satellite configuration needs to sense a ground projection range larger than a communication coverage range, wherein the coverage radius 475km of the former is the sum of the coverage radius 400km and ddr of the latter, ddr is the sum of the range 25km additionally covered by the sidelobe of-3 dBc to-25 dBc when the satellite points to the most marginal wave position and the distance 50km of time flight of the satellite 36 x 0.2s (sensing period, time consumed by sensing all positions in the coverage area).
The frequency spectrum sensing processing equipment processes the received first output signal, identifies the frequency band B of the signal, estimates the direction of the signal source to obtain the position P of the signal source, and informs the frequency band and the position information of the first output signal to the service processing equipment and the inter-satellite transmission equipment;
the time for finishing spectrum sensing of 1 wave position is 2ms, during the spectrum sensing, the satellite does not transmit a same frequency signal, only the spectrum of 1 wave position is sensed within every 200ms, 200ms is far greater than 2ms, and the satellite normally communicates within the rest 198ms, so that the total sensing time in the coverage area is 7.2s, namely the sensing period.
And the service processing equipment plans a service area and an available frequency band according to the frequency band and the position information of the last sensing period, and the frequency band and the position information of the sensing period are used for the next sensing period.
And the service processing equipment plans the wave position related to the service not to provide service according to the frequency band and the position information of the received first output signal, and the wave position to be avoided is all wave positions overlapped by a circle formed by the position of the ground radiation source and the positioning error and the wave position covered by an antenna with-3 dBc to-25 dBc. And the service antenna does not point to the corresponding service area according to the control command of the service processing equipment, and amplifies the second output signal transmitted by the service processing equipment and radiates the amplified second output signal to the space.
When the service processing equipment allocates frequency resources, the corresponding frequency band is removed by deleting the subcarriers, and the generated signal is transmitted to a service antenna, so that the purpose of avoiding the frequency is achieved. The frequency band to be avoided is the bandwidth of 5MHz of the ground radar working frequency band B extension, and 5MHz is the bandwidth corresponding to-25 dBc of signal roll-off. In order to ensure that the power of a new signal generated by the amplifier in a frequency band to be avoided does not exceed the standard, a certain linearity requirement needs to be met.
The inter-satellite transmission equipment informs the position and the frequency of the radiation source to the adjacent satellite, the adjacent satellite naturally has space isolation because the position of the radiation source is not covered by the adjacent satellite, whether frequency isolation is adopted again is determined according to the total isolation requirement, the corresponding subcarrier is removed, and the isolation is further improved.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.
Claims (8)
1. A satellite communication system with spectrum sensing and communication coordination, comprising: a spectrum sensing antenna, a spectrum sensing processing device, a service antenna, a service processing device and an inter-satellite transmission device,
wherein the content of the first and second substances,
the spectrum sensing antenna is used for receiving and frequency converting the radiation signal and outputting a first output signal to the spectrum sensing processing equipment;
the frequency spectrum sensing processing equipment is used for processing the received first output signal and transmitting the frequency band and position information of the first output signal to the service processing equipment and the inter-satellite transmission equipment;
the service processing equipment plans a wave position related to the first output signal not to provide service according to the frequency band and the position of the first output signal, and rejects the corresponding frequency band in a subcarrier deleting mode when frequency band resources are allocated, and transmits a generated second output signal to a service antenna;
the service antenna does not point to a service area corresponding to a wave position related to the first output signal according to a control instruction of the service processing equipment, and a second output signal transmitted by the service processing equipment is amplified by an amplifier and then radiated to a space;
and the inter-satellite transmission equipment informs the adjacent satellite of the frequency band and the position information of the first output signal.
2. The system of claim 1, wherein the spectrum sensing antenna covers a communication service frequency band of the system, and is in the form of an antenna with adjustable beam direction.
3. The system of claim 1, wherein the spectrum sensing processing device processes the received first output signal, and wherein the processing comprises identifying a frequency band in which the first output signal is located, and estimating a direction from which the first output signal originates to obtain its location.
4. The system of claim 1, wherein the spectrum sensing time for completing 1 wave bit is dT, during the spectrum sensing, the satellite does not transmit the same frequency signal, the spectrum of 1 wave bit is sensed in every dT time, dT is much larger than dT, during the rest dT-dT time, the satellite normally communicates, the total time for sensing all wave bits is dT × N, which is called a sensing period, and N is the wave bit number required for sensing all the coverage areas.
5. The system of claim 1, wherein the amplifier meets linearity requirements to ensure that the signal power produced by the amplifier in the frequency band to be avoided does not exceed a standard.
6. The system of claim 1, wherein the spectral sensing antenna has a G/T value that meets the requirements for detecting the side lobes of the terrestrial radiation source, and a positioning error value that is comparable to the size of the communication beam footprint.
7. The system of claim 1, wherein the ground projection range that the spectrum sensing antenna needs to sense is larger than the communication coverage range, the former coverage radius is the sum of the latter coverage radius and ddr, and ddr is the sum of the range of the extra coverage of the side lobe when the satellite points to the most marginal wave position and the distance of the time flight consumed by the satellite at all positions in the spectrum sensing coverage area.
8. The system of claim 4, wherein the service processing device plans the service area and the available frequency band according to the frequency band and the location information obtained in the previous sensing period, and the frequency band and the location information obtained in the current sensing period are used in the next sensing period.
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