Elastic multi-region spectrum sensing method, system, storage medium and satellite end

Abstract

The application provides an elastic multi-region spectrum sensing method, system, storage medium and satellite terminal, which is applied to a sub-satellite in a satellite-ground communication scene. The sub-satellite periodically passes through a beam coverage area of a main satellite. The method comprises the following steps: dividing the beam coverage area of the main satellite into multiple sensing regions; determining a currently located sensing region of the sub-satellite; and performing spectrum sensing based on the currently located sensing region. The elastic multi-region spectrum sensing method, system, storage medium and satellite terminal of the application realize elastic spectrum sensing based on multi-level regions in the spatial dimension, and effectively improve the detection probability and throughput performance of the system.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a flexible multi-region spectrum sensing method, system, storage medium, and satellite terminal. Background Technology

[0002] As mobile communication networks have evolved from Generation 1 to Generation 5, changes in lifestyles have driven changes in mobile communication methods. Meanwhile, innovation in mobile communication technology continues to drive the development of societal needs.

[0003] With the development of wireless communication and aerospace technologies, we are currently in the transition phase from the 5G era to the 6G era. After a long and extensive period of research, terrestrial communication technologies have gradually reached saturation and maturity. Meanwhile, with the rapid development of low-Earth orbit satellite technology in recent years, space-ground integration has become the main direction for future development, and three-dimensional, ubiquitous terminal connectivity will be a key feature of future 6G mobile communication.

[0004] With the gradual integration of terrestrial internet, mobile communication networks, and space network services, the construction of a unified space and terrestrial integrated information network has become an important feature of the future sixth-generation mobile communication network. It will consist of high Earth orbit satellites, medium Earth orbit satellites, low Earth orbit satellites, and terrestrial communication systems to form a multi-layered heterogeneous network with a large spatiotemporal scale.

[0005] The integrated space-ground communication architecture for future 6G is primarily designed to achieve wide-area intelligent connectivity for everything. In the future, intelligent systems such as autonomous vehicles, unmanned logistics systems, and remote-operation robots will be widely deployed globally, and information exchange and collaborative work between these systems will be ubiquitous. This will be beyond the capabilities of limited terrestrial systems. Driven by various business needs and technological advancements, satellite and space communications will develop in an integrated manner with terrestrial communications, merging at different levels such as spectrum and systems to achieve seamless global three-dimensional coverage. Of course, new technologies and visions bring new challenges. Compared to traditional satellite communication systems, integrated space-ground communication systems require more comprehensive capabilities, including computing power, AI capabilities, and security capabilities. Simultaneously, with the addition of satellites, the scarcity of spectrum resources further increases, and the security issues of heterogeneous network integration and ubiquitous connectivity cannot be ignored. Furthermore, the high-speed mobility of satellites also presents significant challenges to integrated space-ground communication systems.

[0006] From a spectrum resource perspective, since terrestrial networks have begun using higher spectrum that overlaps with satellite communications, satellite terminals can potentially access terrestrial networks in an integrated manner. However, effective spectrum management technologies are needed to avoid congestion and interference caused by satellite-terrestrial spectrum sharing. Spectrum resources are non-renewable and scarce resources for both terrestrial and space communication systems. Traditional spectrum resource allocation uses a fixed allocation scheme, assigning frequencies based on national borders and regions. Space communication systems, on the other hand, allocate frequency resources according to the International Telecommunication Union's "first-come, first-served" frequency usage principle. Currently, there is an average of one communication satellite per 1° of geostationary orbit, and the phenomenon of two or even multiple satellites sharing the same orbit is very common. Furthermore, frequency resources and orbital resources are not differentiated according to orbit, causing congestion and chaos in spectrum resource allocation. At the same time, the rapid development of large-scale low-Earth orbit satellite constellations further exacerbates the congestion of space frequency and orbital resources. With the growth of user service demands, the satellite frequency usage environment is becoming increasingly complex, and spectrum resources are becoming increasingly scarce, urgently requiring the development of efficient spectrum management technologies.

[0007] Cognitive radio technology, as one of the candidate technologies for future 6G, has been widely favored by scholars. Spectrum sensing technology is a key technology in cognitive radio, which opens up spectrum resources to a certain extent through "throttling" methods. When licensed users are idle, unlicensed users are allowed to use licensed frequency bands for communication, thereby achieving spectrum sharing and improving spectrum utilization. Furthermore, the more thoroughly spectrum holes are explored, the more significant the improvement in spectrum efficiency. In wide-area, ubiquitous terminals, the massive number of accesses further expands the demand for spectrum resources, and spectrum sensing technology's exploration of spectrum holes can effectively alleviate spectrum pressure.

[0008] On the other hand, large-scale low-Earth orbit (LEO) satellite constellations are considered an indispensable and important component of integrated space-ground systems. They can "open up" higher frequency bands on top of existing ones, alleviating spectrum pressure in low-frequency bands to some extent. Furthermore, compared to geostationary orbit (GEO) and medium-to-high orbit (MEO) satellites, LEO satellites are closer to the ground, have shorter communication latency, and are capable of achieving global coverage, demonstrating significant potential.

[0009] In fact, spectrum sensing technology and low-Earth orbit (LEO) satellite technology can be organically combined to fully utilize existing spectrum resources and alleviate spectrum pressure in a "resource-saving and cost-efficient" manner. However, the inherent high-speed mobility of LEO satellites also presents a significant challenge to the integration of these two technologies. The high-speed movement of satellites inevitably leads to the Doppler effect. The drastic channel changes caused by the Doppler effect will inevitably result in a significant reduction in the sensing performance for unlicensed users. Summary of the Invention

[0010] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a flexible multi-region spectrum sensing method, system, storage medium and satellite terminal, which realizes flexible spectrum sensing based on multi-level regions in spatial dimension, effectively improving the detection probability and throughput performance of the system.

[0011] In a first aspect, the present invention provides a flexible multi-region spectrum sensing method, applied to a secondary satellite in a satellite-to-ground communication scenario, wherein the secondary satellite periodically passes through the beam of a primary satellite. The method includes the following steps: dividing the beam coverage area of ​​the primary satellite into multiple sensing regions; determining the current sensing region of the secondary satellite; and performing spectrum sensing based on the current sensing region.

[0012] In one implementation of the first aspect, dividing the beam coverage area of ​​the main satellite into multiple sensing areas includes the following steps:

[0013] The operating speed and orbital altitude, coherence time, duration of a single symbol, and duration of the sensing window of the primary satellite and the secondary satellite are obtained.

[0014] The beam coverage area of ​​the primary satellite and the presence time of the secondary satellite within the beam coverage area are calculated based on the operating speed and orbital altitude of the primary satellite and the secondary satellite.

[0015] Set the first time point of the beam center of the main satellite;

[0016] The second time point at which the coherence time is equal to the duration of the single symbol is calculated;

[0017] The third time point at which the coherence time equals the duration of the sensing window is calculated;

[0018] Based on the relative velocity of the secondary satellite to the primary satellite, the coverage area of ​​the secondary satellite between the second time point and the third time point is the elastic sensing area, and the coverage area of ​​the secondary satellite between the first time point and the third time point is the static sensing area. The coverage area of ​​the secondary satellite during the existence time minus the elastic sensing area and the static sensing area is the rigid sensing area.

[0019] In one implementation of the first aspect, determining the current sensing area of ​​the subsatellite includes the following steps:

[0020] Calculate the current coherence time of the subsatellite;

[0021] When the current coherence time is less than the duration of a single symbol, the subsatellite is determined to be located in the rigid sensing region.

[0022] When the current coherence time is greater than or equal to the duration of the single symbol and less than the duration of the sensing window, the subsatellite is determined to be located in the elastic sensing area.

[0023] When the current coherence time is greater than or equal to the duration of the sensing window, the subsatellite is determined to be located in the static sensing area.

[0024] In one implementation of the first aspect, when the current sensing area of ​​the subsatellite is the static sensing area, performing spectrum sensing based on the current sensing area includes the following steps:

[0025] Acquire the sensing signal of the static sensing area;

[0026] Extract the feature values ​​of the sensed signal;

[0027] When the feature value is greater than the first threshold value, it is determined that there is a main satellite signal in the static sensing area; otherwise, communication is established with the ground user based on the static sensing area.

[0028] In one implementation of the first aspect, when the current sensing area of ​​the subsatellite is the elastic sensing area, performing spectrum sensing based on the current sensing area includes the following steps:

[0029] The elastic sensing region is elastically sliced ​​to obtain multiple slice regions; wherein the slice unit duration of the elastic slice is between the duration of a single symbol and half the duration of a sensing window;

[0030] Acquire the sensing signals of each slice region and extract the slice feature values ​​of the sensing signals of each slice region;

[0031] The feature values ​​of each slice are merged to obtain the fused feature value;

[0032] When the fused feature value is greater than the second threshold value, it is determined that there is a main satellite signal in the elastic sensing area; otherwise, communication is established with the ground user based on the elastic sensing area.

[0033] In one implementation of the first aspect, when the current sensing area of ​​the subsatellite is the rigid sensing area, performing spectrum sensing based on the current sensing area includes the following steps:

[0034] The rigid sensing region is sliced ​​into granular sections to obtain multiple granular regions; wherein the granular section slice unit duration is the duration of a single symbol.

[0035] Acquire the sensing signals of each granularity region and extract the granularity feature values ​​of the sensing signals of each granularity region;

[0036] By fusing feature values ​​at various granularities, a fused feature value is obtained.

[0037] When the fused feature value is greater than the third threshold, it is determined that there is a main satellite signal within the rigid sensing area; otherwise, communication is established with the ground user based on the rigid sensing area.

[0038] In one implementation of the first aspect, when the subsatellite is not in any sensing area, the subsatellite re-determines its current sensing area after waiting for a preset time.

[0039] Secondly, the present invention provides a flexible multi-region spectrum sensing system for use with a secondary satellite in a satellite-to-ground communication scenario. The secondary satellite periodically passes through the beam coverage area of ​​the primary satellite. The system includes a partitioning module, a determination module, and a sensing module.

[0040] The division module is used to divide the beam coverage area of ​​the main satellite into multiple sensing areas;

[0041] The determining module is used to determine the current sensing area of ​​the sub-satellite;

[0042] The sensing module is used to perform spectrum sensing based on the current sensing area.

[0043] Thirdly, the present invention provides a storage medium on which a computer program is stored, which, when executed by a processor, implements the above-described flexible multi-region spectrum sensing method.

[0044] Fourthly, the present invention provides a satellite terminal, comprising: a processor and a memory;

[0045] The memory is used to store computer programs;

[0046] The processor is used to execute the computer program stored in the memory, so that the satellite performs the above-described flexible multi-region spectrum sensing method.

[0047] As described above, the flexible multi-region spectrum sensing method, system, storage medium, and satellite terminal of the present invention have the following beneficial effects:

[0048] (1) In the application scenario of two low-orbit satellites, by dividing the main satellite beam into regions such as static sensing region, elastic sensing region and rigid sensing region, and designing corresponding sensing thresholds for different regions, the detection probability and throughput performance of the system can be effectively improved.

[0049] (2) It solves the problem of difficulty in detecting primary users in high-speed satellite mobile communication environment and alleviates the problem of satellite spectrum shortage;

[0050] (3) The flexible spectrum sensing scheme based on the spatial dimension of multi-level regional division effectively overcomes the negative impact of drastic channel changes. Attached Figure Description

[0051] Figure 1 The flowchart shown is an embodiment of the flexible multi-region spectrum sensing method of the present invention;

[0052] Figure 2 The diagram shows a division of the satellite beam coverage area in one embodiment.

[0053] Figure 3 The diagram shows a structural schematic of a dual-antenna transmitter based on CDD technology in one embodiment.

[0054] Figure 4 The diagram shown is a schematic representation of a sub-satellite performing flexible multi-region spectrum sensing in one embodiment of the present invention;

[0055] Figure 5 The diagram shown is a structural schematic of the flexible multi-region spectrum sensing system of the present invention in one embodiment.

[0056] Figure 6 The diagram shown is a structural schematic of the satellite terminal of the present invention in one embodiment. Detailed Implementation

[0057] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0058] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0059] The flexible multi-region spectrum sensing method, system, storage medium, and satellite terminal of the present invention achieve flexible spectrum sensing based on multi-level regions in spatial dimension by dividing the beam of the main satellite into multiple sensing regions. This effectively improves the detection probability and throughput performance of the system, solves the problem of difficulty in detecting the main user in the high-speed mobile communication environment of satellite, and alleviates the problem of satellite spectrum shortage, thus making it highly practical.

[0060] The flexible multi-region spectrum sensing method of the present invention is applied to secondary satellites in satellite-to-ground communication scenarios, wherein the secondary satellites periodically pass through the beam coverage area of ​​the primary satellite. For example... Figure 1 As shown, in one embodiment, the flexible multi-region spectrum sensing method of the present invention includes steps S1 to S3.

[0061] Step S1: Divide the beam coverage area of ​​the main satellite into multiple sensing areas.

[0062] Specifically, in this invention, the primary satellite and the secondary satellite are two low-orbit satellites with an altitude difference between them.

[0063] In one embodiment, dividing the beam coverage area of ​​the main satellite into multiple sensing areas includes the following steps:

[0064] 11) Obtain the operating speed and orbital altitude, coherence time, duration of a single symbol, and duration of the sensing window of the primary satellite and the secondary satellite.

[0065] Among them, coherence time f d (t) represents the Doppler frequency. The Doppler frequency f d The calculation process for (t) is as follows:

[0066]

[0067]

[0068]

[0069] Where R E R represents the Earth's radius, R1 and R2 represent the orbital altitudes of the primary and secondary satellites, respectively, and ω1 and ω2 represent the angular velocities of the primary and secondary satellites, respectively. i = 1, 2, G is the gravitational constant 6.67 * 10 - 11 Nm 2 / kg 2 M E The mass of Earth is 5.98 x 10⁻⁶. 24 kg. The duration of a single symbol is determined by the subcarrier spacing and is the reciprocal of the subcarrier spacing. The duration of the sensing window is a predefined value for the subsatellite.

[0070] 12) Calculate the beam coverage area of ​​the main satellite and the presence time of the secondary satellite within the beam coverage area based on the operating speed and orbital altitude of the main satellite and the secondary satellite.

[0071] The duration of the presence of the subsatellite within the beam coverage area. 2r*tanθ represents the beam coverage area of ​​the primary satellite, r represents the orbital altitude difference between the primary and secondary satellites, θ represents half of the beam angle of the primary satellite, and v1 and v2 represent the orbital speeds of the primary and secondary satellites, respectively. It should be noted that the beam coverage area in this invention...

[0072] 13) Set the first time point t1 of the beam center of the main satellite.

[0073] To simplify the calculation, the first time point t1 is set to 0.

[0074] 14) Calculate the second time point t2 where the coherence time is equal to the duration of a single symbol.

[0075] 15) Calculate the third time point t3, where the coherence time is equal to the duration of the perception window.

[0076] 16) Based on the relative velocity of the secondary satellite to the primary satellite, the coverage area of ​​the secondary satellite between the second time point t2 and the third time point t3 is the elastic sensing area, and the coverage area of ​​the secondary satellite between the first time point t1 and the third time point t3 is the static sensing area. The coverage area of ​​the secondary satellite during the existence time minus the elastic sensing area and the static sensing area is the rigid sensing area.

[0077] The formulas for calculating the operating velocities v1 and v2 of the primary and secondary satellites are as follows:

[0078]

[0079]

[0080] The elastic sensing region d flexible =2|v1-v2||t2-t3|.

[0081] The static sensing area d flexible = 2|v1-v2||t3-t1|. Preferably, when t1 = 0, the static sensing area...

[0082] d flexible =2|v1-v2||t3|.

[0083] The rigid sensing region d flexible =2|v1-v2||t total -t2|.

[0084] like Figure 2As shown, region 1 is the rigid sensing region, region 2 is the elastic sensing region, and region 3 is the static sensing region. It should be noted that in this invention, the beam coverage area, rigid sensing region, elastic sensing region, and static sensing region refer to the length of the corresponding beam coverage.

[0085] Step S2: Determine the current sensing area of ​​the subsatellite.

[0086] Specifically, the current coherence time of the subsatellite is first calculated. Then, if the current coherence time is less than the duration of a single symbol, the subsatellite is determined to be located in the rigid sensing region; if the current coherence time is greater than or equal to the duration of a single symbol and less than the sensing window duration, the subsatellite is determined to be located in the elastic sensing region; and if the current coherence time is greater than or equal to the sensing window duration, the subsatellite is determined to be located in the static sensing region.

[0087] Step S3: Perform spectrum sensing based on the current sensing area.

[0088] Specifically, for downlink communication, the primary satellite acts as a base station, establishing communication with the ground user group using a simultaneous transmission and non-transmission method. When the secondary satellite, orbiting slightly lower, enters the beam coverage area of ​​the primary satellite, it first determines its current sensing area and then uses the corresponding sensing algorithm for spectrum sensing.

[0089] Cyclic Delay Diversity (CDD) is a transmit diversity technique that uses multiple antennas at the transmitter. Before transmission, each antenna cyclically shifts the OFDM symbol and adds a cyclic prefix before transmitting. This is equivalent to using a shift in the time domain to introduce a phase shift in the frequency domain to achieve the diversity effect.

[0090] To minimize the need for prior information and the waste of spectrum resources in spectrum sensing, this invention employs CDD (Cyclic Delay Difference) technology to embed signal cyclic delay characteristics. For secondary satellites, only the cyclic delay of the primary satellite needs to be known, and CDD does not consume any spectrum resources. Specifically, the cyclic stationary characteristic identifier of the primary satellite is embedded into the OFDM signal stream in the form of an artificial cyclic delay. For dual-antenna transmission structures, such as... Figure 3 As shown, on the first antenna, the data information is directly generated as an OFDM signal after QAM modulation, a cyclic prefix is ​​added, and then it is transmitted. On the second antenna, the OFDM signal needs to be cyclically shifted according to an artificial cyclic delay before adding the cyclic prefix.

[0091] Therefore, at the signal transmitting end, this invention utilizes CDD technology to embed an artificial cyclic delay into the OFDM signal stream as a cyclic stationary feature of the signal. At the receiving end, the feature value of the received signal needs to be evaluated. If the feature value reaches a certain threshold, the received signal is considered to contain a primary satellite signal; otherwise, the received signal is considered to contain only noise. Because noise is generally stationary and does not possess cyclic stationary characteristics, the presence of a primary satellite signal can be determined by calculating the cyclic stationary feature value of the signal.

[0092] The received downlink and uplink signals are configured as follows:

[0093]

[0094]

[0095] Where r(n) represents the received signal, v(n) represents the noise, h1 and h2 represent the channel coefficients, and s(n) represents the transmitted signal. That is, if the main satellite has not established communication with the ground user at the current moment, then there is only noise in the channel, and the state is H0. Conversely, if the main satellite is communicating, the state is H1.

[0096] Therefore, the calculation of the characteristic value of the received signal can be expressed as:

[0097]

[0098] Here, T represents the sampling signal length, and Δ represents the cyclic feature delay. The threshold value required for judgment is actually related to noise, because its setting needs to consider the false alarm probability, i.e., the probability that the noise characteristic value is higher than the threshold when the main satellite is absent. Correspondingly, there is the detection probability, i.e., the probability that the signal characteristic value is higher than the threshold when the main satellite is present. These two are mutually restrictive; by studying the noise distribution, the relationship between the false alarm probability and the threshold value can be obtained. Where P f This represents the probability of a false alarm. This represents noise energy. In this invention, it is assumed that the false alarm probability is kept at 0.1, and the corresponding threshold value is then obtained.

[0099] Therefore, spectrum sensing based on the current sensing area includes the following three scenarios:

[0100] (i) The current sensing area of ​​the subsatellite is the static sensing area.

[0101] The Doppler effect is relatively small in the static sensing region, and the coherence time is longer than the sensing window duration, so it can be considered a static channel. Therefore, during spectrum sensing, the sensing signal in the static sensing region is first acquired; then, the feature value |F| of the sensing signal is extracted. When the feature value is greater than a first threshold, it is determined that a primary satellite signal exists in the static sensing region, and spectrum sensing continues until the secondary satellite leaves the beam coverage area or the primary satellite signal is detected to no longer exist; otherwise, communication is established with the ground user based on the static sensing region.

[0102] (ii) The current sensing area of ​​the subsatellite is the elastic sensing area.

[0103] The coherence time of the elastic sensing region is shorter than the duration of the sensing window. This will cause the signal's characteristic values ​​to cancel each other out due to phase superposition, becoming submerged in noise interference. Therefore, it is necessary to process the signal within the sensing window by appropriately slicing the signal to ensure that the duration of each slice is less than or equal to the length of the coherence time. Thus, as... Figure 4 As shown, during spectrum sensing, the flexible sensing area is first elastically sliced ​​to obtain multiple slice regions; the slice unit duration of the elastic slice is between the duration of a single symbol and half the duration of a sensing window. Then, the sensing signals of each slice region are acquired, and the slice feature values ​​of the sensing signals of each slice region are extracted. Next, the slice feature values ​​are fused by de-phase superposition to obtain a fused feature value. Finally, when the fused feature value is greater than a second threshold, it is determined that a primary satellite signal exists within the flexible sensing area, and spectrum sensing continues until the secondary satellite leaves the beam coverage area or the primary satellite signal is detected to be absent; otherwise, communication is established with the ground user based on the flexible sensing area.

[0104] (iii) The current sensing area of ​​the subsatellite is the rigid sensing area.

[0105] The coherence time of the rigid sensing region is less than the duration of the sensing window. This will cause the signal's eigenvalues ​​to cancel each other out due to phase superposition, becoming submerged in noise interference. Therefore, it is necessary to process the signal within the sensing window by appropriately slicing the signal to ensure that the duration of each slice is less than or equal to the length of the coherence time. Thus, as... Figure 4As shown, during spectrum sensing, the rigid sensing region is first sliced ​​into multiple granular regions; the slice duration is the duration of a single symbol. Then, the sensing signals of each granular region are acquired, and the granular feature values ​​of each region are extracted. Next, the granular feature values ​​are fused using dephase addition to obtain a fused feature value. Finally, when the fused feature value is greater than a third threshold, it is determined that a primary satellite signal exists within the rigid sensing region. Spectrum sensing continues until the secondary satellite leaves the beam coverage area or the primary satellite signal is detected to be absent; otherwise, communication is established with the ground user based on the rigid sensing region.

[0106] Furthermore, when the subsatellite is not in any sensing area, it cannot perform spectrum sensing. Therefore, the subsatellite will wait for a preset period of time before re-determining its current sensing area.

[0107] The scope of protection of the elastic multi-region spectrum sensing method described in this embodiment is not limited to the execution order of the steps listed in this embodiment. Any solution implemented by adding, subtracting, or replacing steps in the prior art based on the principle of this invention is included within the scope of protection of this invention.

[0108] This invention also provides a flexible multi-region spectrum sensing system, which can implement the flexible multi-region spectrum sensing method described in this invention. However, the implementation device of the flexible multi-region spectrum sensing method described in this invention includes, but is not limited to, the structure of the flexible multi-region spectrum sensing system listed in this embodiment. All structural modifications and substitutions of the prior art made according to the principles of this invention are included within the protection scope of this invention.

[0109] The flexible multi-region spectrum sensing system of this invention is applied to secondary satellites in satellite-to-ground communication scenarios, wherein the secondary satellites periodically pass through the beam coverage area of ​​the primary satellite. For example... Figure 5 As shown, in one embodiment, the flexible multi-region spectrum sensing system includes a partitioning module 51, a determination module 52, and a sensing module 53.

[0110] The division module 51 is used to divide the beam coverage area of ​​the main satellite into multiple sensing areas.

[0111] The determining module 52 is connected to the dividing module 51 and is used to determine the current sensing area of ​​the subsatellite.

[0112] The sensing module 53 is connected to the determining module 52 and is used to perform spectrum sensing based on the current sensing area.

[0113] The structure and principle of the division module 51, the determination module 52 and the sensing module 53 correspond one-to-one with the steps in the above-mentioned elastic multi-region spectrum sensing method, so they will not be repeated here.

[0114] It should be noted that the division of the various modules in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can be implemented entirely in software via processing element calls; they can be fully implemented in hardware; or some modules can be implemented by processing element calls to software, while others are implemented in hardware. For example, module x can be a separate processing element, or it can be integrated into a chip in the above device. Alternatively, it can be stored as program code in the memory of the above device, and its function can be called and executed by a processing element of the device. The implementation of other modules is similar. Moreover, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element mentioned here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed through the integrated logic circuits in the hardware of the processor element or through software instructions.

[0115] For example, these modules can be one or more integrated circuits configured to implement the above methods, such as one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs). As another example, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together to form a system-on-a-chip (SOC).

[0116] This invention also provides a computer-readable storage medium. Those skilled in the art will understand that all or part of the steps in the flexible multi-region spectrum sensing method of the above embodiments can be implemented by a program instructing a processor. The program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof. The storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. This available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital video disc (DVD)), or a semiconductor medium (e.g., solid-state drive (SSD)).

[0117] like Figure 6 As shown, in one embodiment, the satellite terminal of the present invention includes a processor 61 and a memory 62.

[0118] The memory 62 is used to store computer programs.

[0119] The memory 62 includes various media capable of storing program code, such as ROM, RAM, magnetic disk, USB flash drive, memory card, or optical disk.

[0120] The processor 61 is connected to the memory 62 and is used to execute the computer program stored in the memory 62 so that the satellite terminal performs the above-described flexible multi-area spectrum sensing method.

[0121] Preferably, the processor 61 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0122] In summary, the flexible multi-region spectrum sensing method, system, storage medium, and satellite terminal of this invention, in the application scenario of two low-Earth orbit satellites, effectively improve the detection probability and throughput performance of the system by dividing the main satellite beam into regions, such as static sensing regions, flexible sensing regions, and rigid sensing regions, and designing corresponding sensing thresholds for different regions. It solves the problem of difficulty in detecting primary users in high-speed satellite mobile communication environments and alleviates the problem of satellite spectrum shortage. The multi-level regional division flexible spectrum sensing scheme based on spatial dimensions effectively overcomes the negative impact of drastic channel changes. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A flexible multi-region spectrum sensing method, applied to a secondary satellite in a satellite-to-ground communication scenario, wherein the secondary satellite periodically passes through the beam coverage area of ​​the primary satellite, characterized in that: The method includes the following steps: The beam coverage area of ​​the main satellite is divided into multiple sensing areas; Determine the current sensing area of ​​the subsatellite; Perform spectrum sensing based on the current sensing area; Dividing the beam coverage area of ​​the main satellite into multiple sensing areas includes the following steps: The operating speed and orbital altitude, coherence time, duration of a single symbol, and duration of the sensing window of the primary satellite and the secondary satellite are obtained. The beam coverage area of ​​the primary satellite and the presence time of the secondary satellite within the beam coverage area are calculated based on the operating speed and orbital altitude of the primary satellite and the secondary satellite. Set the first time point of the beam center of the main satellite; The second time point at which the coherence time is equal to the duration of the single symbol is calculated; The third time point at which the coherence time equals the duration of the sensing window is calculated; Based on the relative velocity of the secondary satellite to the primary satellite, the coverage area of ​​the secondary satellite between the second time point and the third time point is the elastic sensing area, and the coverage area of ​​the secondary satellite between the first time point and the third time point is the static sensing area. The coverage area of ​​the secondary satellite during the existence time minus the elastic sensing area and the static sensing area is the rigid sensing area. Determining the current sensing area of ​​the subsatellite includes the following steps: Calculate the current coherence time of the subsatellite; When the current coherence time is less than the duration of a single symbol, the subsatellite is determined to be located in the rigid sensing region. When the current coherence time is greater than or equal to the duration of the single symbol and less than the duration of the sensing window, the subsatellite is determined to be located in the elastic sensing area. When the current coherence time is greater than or equal to the duration of the sensing window, the subsatellite is determined to be located in the static sensing area. When the current sensing area of ​​the subsatellite is the elastic sensing area, spectrum sensing based on the current sensing area includes the following steps: The elastic sensing region is elastically sliced ​​to obtain multiple slice regions; wherein the slice unit duration of the elastic slice is between the duration of a single symbol and half the duration of a sensing window; Acquire the sensing signals of each slice region and extract the slice feature values ​​of the sensing signals of each slice region; The feature values ​​of each slice are merged to obtain the fused feature value; When the fused feature value is greater than the second threshold value, it is determined that there is a main satellite signal in the elastic sensing area; otherwise, communication is established with the ground user based on the elastic sensing area.

2. The elastic multi-region spectrum sensing method of claim 1, wherein: When the current sensing area of ​​the subsatellite is the static sensing area, spectrum sensing based on the current sensing area includes the following steps: Acquire the sensing signal of the static sensing area; Extract the feature values ​​of the sensed signal; When the feature value is greater than the first threshold value, it is determined that there is a main satellite signal in the static sensing area; otherwise, communication is established with the ground user based on the static sensing area.

3. The flexible multi-region spectrum sensing method according to claim 1, characterized in that: When the current sensing area of ​​the subsatellite is the rigid sensing area, spectrum sensing based on the current sensing area includes the following steps: The rigid sensing region is sliced ​​into granular sections to obtain multiple granular regions; wherein the granular section slice unit duration is the duration of a single symbol. Acquire the sensing signals of each granularity region and extract the granularity feature values ​​of the sensing signals of each granularity region; By fusing feature values ​​at various granularities, a fused feature value is obtained. When the fused feature value is greater than the third threshold, it is determined that there is a main satellite signal within the rigid sensing area; otherwise, communication is established with the ground user based on the rigid sensing area.

4. The elastic multi-region spectrum sensing method of claim 1, wherein: When the subsatellite is not in any sensing area, the subsatellite will re-determine its current sensing area after waiting for a preset time.

5. A flexible multi-region spectrum sensing system, applied to a secondary satellite in a satellite-to-ground communication scenario, wherein the secondary satellite periodically passes through the beam coverage area of ​​the primary satellite, characterized in that: The system includes a partitioning module, a determination module, and a perception module; The division module is used to divide the beam coverage area of ​​the main satellite into multiple sensing areas; The determining module is used to determine the current sensing area of ​​the sub-satellite; The sensing module is used to perform spectrum sensing based on the current sensing area. Dividing the beam coverage area of ​​the main satellite into multiple sensing areas includes the following steps: The operating speed and orbital altitude, coherence time, duration of a single symbol, and duration of the sensing window of the primary satellite and the secondary satellite are obtained. The beam coverage area of ​​the primary satellite and the presence time of the secondary satellite within the beam coverage area are calculated based on the operating speed and orbital altitude of the primary satellite and the secondary satellite. Set the first time point of the beam center of the main satellite; The second time point at which the coherence time is equal to the duration of the single symbol is calculated; The third time point at which the coherence time equals the duration of the sensing window is calculated; Based on the relative velocity of the secondary satellite to the primary satellite, the coverage area of ​​the secondary satellite between the second time point and the third time point is the elastic sensing area, and the coverage area of ​​the secondary satellite between the first time point and the third time point is the static sensing area. The coverage area of ​​the secondary satellite during the existence time minus the elastic sensing area and the static sensing area is the rigid sensing area. Determining the current sensing area of ​​the subsatellite includes the following steps: Calculate the current coherence time of the subsatellite; When the current coherence time is less than the duration of a single symbol, the subsatellite is determined to be located in the rigid sensing region. When the current coherence time is greater than or equal to the duration of the single symbol and less than the duration of the sensing window, the subsatellite is determined to be located in the elastic sensing area. When the current coherence time is greater than or equal to the duration of the sensing window, the subsatellite is determined to be located in the static sensing area. When the current sensing area of ​​the subsatellite is the elastic sensing area, spectrum sensing based on the current sensing area includes the following steps: The elastic sensing region is elastically sliced ​​to obtain multiple slice regions; wherein the slice unit duration of the elastic slice is between the duration of a single symbol and half the duration of a sensing window; Acquire the sensing signals of each slice region and extract the slice feature values ​​of the sensing signals of each slice region; The feature values ​​of each slice are merged to obtain the fused feature value; When the fused feature value is greater than the second threshold value, it is determined that there is a main satellite signal in the elastic sensing area; otherwise, communication is established with the ground user based on the elastic sensing area.

6. A storage medium having stored thereon a computer program, characterized in that When the program is executed by the processor, it implements the flexible multi-region spectrum sensing method as described in any one of claims 1 to 4.

7. A satellite terminal, characterized in that, include: Processor and memory; The memory is used to store computer programs; The processor is used to execute the computer program stored in the memory to cause the satellite to perform the flexible multi-region spectrum sensing method according to any one of claims 1 to 4.

Images