A multi-beam satellite uplink resource management method for Internet of Things communication

Abstract

The present invention discloses a multi-beam satellite uplink resource management method for Internet of Things communication. This method utilizes the beam management list generated and maintained at the satellite end, and uses the spatial degrees of freedom provided by the beams to perform interference management and beam cooperation for users with different data priorities and interference conditions, so as to improve the system spectrum efficiency, improve the continuity of signal coverage, and enhance the controllability of signal quality. The beam resource allocation principle is to satisfy the QoS of each terminal service as much as possible, and at the same time process the current inflow load of the system, that is, service data, as much as possible.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-beam systems, and particularly to a multi-beam satellite uplink resource management method for Internet of Things (IoT) communication. Background Art

[0002] For the IoT, most of its service operations are short burst data services, such as the position, traveling speed, destination, etc. of ships in the maritime IoT. To meet the QoS requirements of IoT communication, resource management in multi-beam satellite communication systems is a key link. In some satellite wireless communication systems, such as the VHF (Very High Frequency) Data Exchange System (VDES) used for international maritime communication, in the currently publicly available technical characteristic document ITU-R M.2092-0 and the technical discussion document IALA G1139 of relevant organizations represented by IALA, the satellite uses a single-beam antenna (such as a Yagi antenna). Because of the high altitude of the satellite and the large coverage area (field of view) on the Earth's surface, the spectral efficiency is extremely low. In the case of a lack of communication spectrum resources and an increasing number of maritime IoT devices, it is necessary to introduce a multi-beam full frequency reuse satellite system to increase the regional spectral efficiency (spatial spectral efficiency) through spatial beams to make up for the serious shortage of the spectrum. Currently, a single satellite in China can have more than 60 beams. In theory, the system capacity can be increased by 60 times. However, to ensure no gaps between beams (to ensure the continuity of coverage), in practical conditions, the beams cannot avoid overlapping, so it is impossible to achieve complete orthogonality and interference between beams is introduced. Compared with the communication quality under single-antenna coverage, not only the SINR will be affected, but also the continuity and uniformity will be damaged, and even the increase in system capacity brought by multi-beams may be offset. Therefore, a practical multi-beam system resource management scheme is extremely crucial for fully obtaining the benefits brought by multi-beams, which is relied on to ensure the consistency and uniformity of the communication quality in the multi-beam coverage area, especially the continuity of communication at the beam edge junction, and to meet the QoS requirements of different maritime services. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a multi-beam satellite uplink resource management method for IoT communication to solve the technical problems in the background art. The present invention can not only increase the utilization efficiency of spectrum resources, but more importantly, can better meet the QoS requirements of terminal services.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A multi-beam satellite uplink resource management method for Internet of Things communication, the method comprising the following steps:

[0006] Step S1: For a multi-beam satellite communication system, which includes a satellite terminal and multiple user terminals, the user terminal obtains the beam ID from the downlink signal, and the satellite terminal downlink signal is scrambled with the corresponding ID according to different beams; wherein, when a certain user terminal among the multiple user terminals needs to upload resources to the satellite terminal, the user terminal sends an uplink resource request to the satellite terminal, and the user terminal selects the ID of the beam with the strongest signal strength from the obtained downlink signals of multiple different beams, scrambles the resource request signal, and sends the request signal to the satellite terminal on the resources specified by the system;

[0007] Step S2: For multiple beams, the satellite terminal selects one of the beams, detects all uplink resource request signals according to the beam ID and records their signal strengths;

[0008] Step S3: On all beams, the satellite terminal repeats Step S2;

[0009] Step S4: According to the signal strength data obtained in Step S2 and Step S3, construct an interference management list, wherein, for the interference management list, its vertical axis is the classification of user terminals, its horizontal axis is the beam classification, or, its vertical axis is the beam classification, its horizontal axis is the user terminal classification, and a threshold value is set, and the signal measurement values lower than the threshold value are set to null;

[0010] Step S5: According to the interference management list in Step S4 and the user service data information in the scheduler, perform beam resource scheduling for the multiple user terminals, wherein, when performing beam resource scheduling, the following principles need to be followed: as much as possible to meet the QoS of each terminal service, and at the same time as much as possible to process the current inflow load of the system;

[0011] Step S6: Scramble the uplink signals of the user terminals assigned to different beams.

[0012] Further, in Step S1, when the user terminal sends an uplink resource request to the satellite terminal, the request includes: data packet size, QoS, and MAC ID, wherein the MAC ID is the hashed ID to reduce the signal load.

[0013] Further, in Step S2, the satellite terminal is on beam φ, and on the time-frequency resources specified by the system, detects all uplink resource request signals with φ as the scrambling code;

[0014] When the uplink resource request signal of a user terminal x is detected by the satellite on (φ,υ), the signal strength output by its detector is expressed as per unit resource energy, as shown in the following formula:

[0015]

[0016] In this formula, Ω is the system time-frequency resource set, is the channel gain of terminal x on (φ,υ), ρ x The energy per unit resource of the signal transmitted by terminal x.

[0017] Furthermore, in step S5, the QoS of each terminal service is satisfied as much as possible, and the current inflow load of the system is processed as much as possible, which is specifically expressed as follows:

[0018] According to the priority, find the largest terminal set in the user terminal set Λ Shared time slot ω, and satisfy:

[0019]

[0020] In this formula, Indicates that user terminal x is allocated time-frequency resource ω∈Ω, and the satellite is allocated time-frequency resource (Φ x ,ω) received by terminal x,Φ x is the beam set participating in the joint reception of the user terminal x signal, and Γ is the threshold value that ensures that the probability of successful reception of data by the satellite terminal is greater than a certain value.

[0021] Furthermore, in the step S6, when the scrambling code is executed, the scrambling code is independent of the beam number but is related to the MAC ID of the user terminal.

[0022] Furthermore, in the multi-beam satellite communication system, signals on different beams are distinguished by different scrambling sequences, and the scrambling sequences are pseudo-random sequences related to the beam numbers, wherein:

[0023] For downlink signals, 42-bit mask Determined according to the following formula:

[0024]

[0025] It is the identification code of mobile communication service in maritime Internet of Things; beam is the identifier of the beam in a multi-beam antenna.

[0026] Further, when there is uplink data, the user terminal initiates a resource request to the satellite side using a specific physical channel, where the specific physical channel is a random access channel, and a pseudo-random sequence related to the selected beam is used as the scrambling code of this uplink signal, and its specific representation is:

[0027]

[0028] The beneficial effects of the present invention are:

[0029] Through the technical solution of the present invention, a multi-beam uplink resource management scheme is formed, which can not only increase the utilization efficiency of spectrum resources to improve system capacity, but also better meet the QoS requirements of terminal services. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the model of the multi-beam satellite communication system provided in Embodiment 1;

[0031] Figure 2 It is a signal strength distribution diagram of the multi-beam satellite communication system provided in Embodiment 1;

[0032] Figure 3 It is an SINR distribution diagram of the multi-beam satellite communication system provided in Embodiment 1;

[0033] Figure 4 It is a schematic diagram of the model of the simplified TDMA system based on time slots as the basic time-frequency resource scheduling granularity provided in Embodiment 1;

[0034] Figure 5 It is a schematic diagram of the process of executing the uplink resource scheduling scheme provided in Embodiment 1;

[0035] Figure 6 It is an uplink resource request provided in Embodiment 1, and its specific schematic diagram of the included content. Detailed Embodiments

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Embodiment 1

[0038] Refer to Figures 1-6 , this embodiment provides a multi-beam satellite uplink resource management method for Internet of Things communication, and the method specifically includes:

[0039] Step S1. For a multi-beam satellite communication system, which includes a satellite terminal and multiple user terminals. In this system, the satellite downlink signal is scrambled with the corresponding beam ID according to the beam it belongs to.

[0040] Step S2. The above-mentioned user terminal obtains the beam ID from the downlink signal. In this embodiment, the downlink signal can be a downlink synchronization signal. Specifically, in this embodiment, a user terminal x can see the downlink signals of multiple different beams, and selects the beam with the maximum signal strength, denoted as beam φ ∈ Φ, where Φ is the set of all beams.

[0041] When a certain user terminal has service data to upload, after scrambling the uplink signal with ID(φ), it sends an uplink resource request to the satellite on the time-frequency resource υ specified by the system for sending request signals.

[0042] Among them, the uplink resource request specifically includes: packet size, QoS, and MAC ID in this embodiment. The MAC ID will be used by the satellite to distinguish service user terminals, such as a 9-digit MMSI, and can be mapped into a smaller number of bits (such as 16 bits) using a hash function to reduce the signal burden.

[0043] Step S3. The satellite terminal detects all uplink resource request signals with φ as the scrambling code on the beam φ on the time-frequency resource specified by the system. Among them, when the uplink resource request signal of a terminal x is detected by the satellite on (φ, υ), the signal strength output by its detector (matched filter) can be expressed as the energy per unit resource:

[0044]

[0045] In formula (1), Ω is the set of system time-frequency resources. is the channel gain of user terminal x on (φ, υ). For details, please refer to Figure 1 , ρ x is the energy per unit resource of the signal transmitted by terminal x.

[0046] The satellite terminal measures the strength of the uplink resource request signal on other beams respectively, obtains the corresponding signal measurement values, and records them as the signal strength of terminal x on beam :

[0047]

[0048] Specifically, in this embodiment, for those beams far from beam φ it can be defaulted to to save the calculation amount.

[0049] Step S4: Execute Step S3 for all beams;

[0050] Step S5: Record all the detected users in Step S4 in the interference management list. For the interference management list, the vertical axis is the classification of terminals, and the horizontal axis is the beam classification, or the vertical axis is the beam classification, and the horizontal axis is the terminal classification. Among them, a threshold is set, and the signal measurement values lower than this threshold are set to zero.

[0051] Step S6: Perform system resource allocation for all user terminals according to the interference management list in Step S5 and the user data priority information maintained by the satellite station. Among them, the system resources include: beam and time-frequency resources. Specifically, in this embodiment, optimization algorithms such as neural network algorithms and deep learning algorithms can be used to perform system resource allocation for all user line terminals;

[0052] Step S7: The user terminals allocated with uplink resources scramble the uplink signals used to transmit service data. This scrambling is independent of the beam number but related to the MAC ID of the terminal to facilitate the satellite receiver to distinguish the signal.

[0053] To more clearly illustrate the multi-beam satellite uplink resource management method for Internet of Things communication provided in this embodiment, a specific case is described below.

[0054] For a satellite communication system, the coverage area of a single satellite base station is determined by the tangent of the satellite to the earth. Since the satellite is far from the ground (>500km), its coverage area is much larger than that of a ground station, which means that a satellite station needs to serve more users. For example, the visual radius of a LEO satellite at a low orbit of 600km is about 2600km. For a MEO satellite at a medium orbit of 2000km, the corresponding visual radius is 4500km. In contrast, the coverage radius of a ground base station with an antenna height of 100m is only 35km, which is much smaller than the coverage area of the satellite station. Obviously, for a narrowband Internet of Things system, a single satellite is difficult to support services within a huge visual range. To improve system capacity, an effective solution is to deploy a multi-beam antenna on the satellite space station to form multiple spatial beams so as to divide the visual range into multiple smaller footprints, that is, coverage areas.

[0055] Satellite stations use multi-beam technology to divide the entire coverage area of the satellite into multiple small beam coverages. Usually, a full-frequency reuse scheme is adopted between the beams, so as to maximize the spatial spectrum utilization efficiency. In this way, the communication resources provided by the satellite communication system to end users have an additional beam dimension in addition to the usual time and frequency dimensions. In the most ideal case, the system capacity under the coverage of a satellite increases linearly with the increase in the number of beams. However, in an actual system, the beams are not completely orthogonal like time-frequency resources, and the coverages of different beams overlap with each other, resulting in interference to the end users in the overlapping area.

[0056] According to the requirements of the on-orbit VDES payload's ground view coverage and the electrical performance of the payload antenna in the space segment, it is necessary to meet the requirement of resolving the time slot conflict of the VDE signal of the ship on the ground by the on-board system. The beam width after antenna beam synthesis should be as narrow as possible. The single antenna has a wide ground view coverage in the VHF band. A multi-beam antenna that forms multiple beams through array formation is the best choice for this system. The VDES payload operates in the VHF band, and the antenna size is relatively large. After array formation, the size of the array is too large, exceeding the satellite envelope range. It is necessary to design the array antenna to be deployable. There are too many array elements, and the complexity of the conventional antenna deployment mechanism is relatively high. And the antenna needs to conform to the satellite structure for large-scale integrated layout requirements due to its structural form. The performance of the VHF antenna is realized by using a thin-film structure. The antenna element uses a flexible thin-film dielectric material. There is an air layer between the thin-film layer and the ground layer. The thin-film layer and the reflection cavity can be deployed through a flexible deployment mechanism, which can not only reduce the weight of the antenna, but also has the characteristics of light weight and low profile of the antenna. The antenna adopts the form of a microstrip slot antenna. To reduce the back radiation of the microstrip slot antenna, a reflection cavity is used to realize the directional radiation of the VHF band antenna. The conventional antenna form is generally divided into three layers, namely the radiation layer, the feeding layer, and the ground layer. In this type of antenna, the distance between the radiation layer and the feeding layer, and the relative position change of the coupled feeding and the radiation element have a greater impact on the electrical performance of the antenna, and it is difficult to process, assemble, and maintain the shape of the antenna array surface. At the same time, the antenna size working in the VDES system is relatively large. Therefore, the antenna design scheme of this system adopts a reflection cavity type antenna scheme with a relatively simple structure. This design scheme has relatively loose requirements for antenna size control and synthesizes 30 beams in total.

[0057] Assume that the orbital altitude of the satellite is 600 km, and the satellite beam coverage is as Figure 1 shown. The received signal strength distribution in the coverage area of a single satellite signal on the Earth's surface is as Figure 2 shown. Figure 2The numbers from 1 to 30 in the figure represent beam numbers. The multi-beam satellite antenna forms a total of 30 receiving beams. The inner layer consists of beams numbered from 1 to 4, the middle layer consists of beams numbered from 5 to 14, and the outer layer consists of beams numbered from 15 to 30. The signal strength is distinguished by colors, and the signal strength values (unit: dBm) corresponding to different colors are represented by the color bar on the right side of the figure. There is actually overlap between different beams, and the signal strength in the figure is the strongest signal value in the overlapping area.

[0058] The signal quality is not only related to the signal strength, but also affected by the interference strength and thermal noise strength it suffers. The signal quality of the satellite receiving the uplink signal from the end user is determined by the signal-to-interference-plus-noise ratio (SINR), that is, the ratio of the total received signal energy to the sum of the total interference energy and the receiver thermal noise. In the traditional receiving framework, the SINR of the satellite receiving the signal from user x at (φ, ω) is:

[0059]

[0060] In this formula (3), user x and user i share the same time-frequency resource ω; N 0 represents the receiver thermal noise power spectral density.

[0061] The average SINR distribution of the uplink signal is as Figure 3 shown, and the middle area indicates a lower SINR. Figure 2 In the middle layer and the inner layer beams where the signal strength is generally high in the figure, the uplink users in the neighboring beams cause greater interference, showing a lower SINR; although the signal strength of the outer layer beams is relatively weak, the interference is relatively small, so they obtain a better SINR. Generally speaking, a lower average SINR level is presented in the beam overlapping area.

[0062] The signals on different beams are distinguished by different scrambling sequences, and this scrambling sequence is a pseudo-random sequence related to the beam number. In this embodiment, the symbol scrambling mode in Document 1 is adopted, which not only forms differences between different terminals, different air interfaces, and physical waveforms of different frequency carriers, but also adds beam difference information.

[0063] Specifically, in this embodiment, for the downlink signal, the 42-bit mask is determined according to the following formula:

[0064]

[0065] In this formula (4), is the mobile communication service identification code (Maritime Mobile Service Identity, MMSI) in the maritime Internet of Things. MMSI consists of 9 decimal digits, and at least 30 bits of binary digits are required to quantify the 9 decimal MMSI; nbeam It is the identifier of the beam in the multi-beam antenna, represented by an 8-bit binary number, and can distinguish up to 256 beams. The above 42-bit mask can be used in conjunction with a 42-bit PN sequence generator to generate a scrambling sequence, referring to Patent

CN110380748 A

[0066] The scrambling sequence of the downlink signals transmitted by different beams in different satellite stations is a parameter related to the satellite terminal, n beam is a parameter related to the beam ID. The lowest bit "1" indicates downlink, "0" indicates uplink, and the highest bit "1" indicates it is a satellite system (to distinguish from the ground communication system "0").

[0067] For the maritime Internet of Things, most of its service operations are short burst data services (Short Burst Data Services), such as ships reporting their positions, traveling speeds, destinations, etc. When there is uplink data, the terminal will use a specific physical channel (such as the random access channel) to initiate a resource request to the satellite station, and use the pseudo-random sequence related to the selected beam (such as the beam index is φ) as the scrambling code of this uplink signal:

[0068]

[0069] Specifically, the fields and sizes included in the uplink resource request are as Figure 6 shown. Among them, the 4-bit scheduling level will be used to determine the user data scheduling priority, which is dynamically determined by its QoS and transmission status (such as waiting time).

[0070] After the uplink resource request signal of terminal x is detected by the satellite on the corresponding system resources (φ, υ), its strength is shown in formula (1). The satellite measures the strength of this uplink resource request signal on other beams respectively, obtains the corresponding signal measurement values, and records them as the signal strength of terminal x on the beam as specifically shown in formula (2).

[0071] Repeat the above process for all detected terminals to obtain a beam management list, as shown in Table 1. The priority in the table is jointly determined by the resource scheduler according to the data waiting time and the delay requirement of its QoS.

[0072] Table 1

[0073]

[0074]

[0075] For the convenience of discussion, consider a TDMA system based on the slot as the basic time-frequency resource scheduling granularity of VDES, specifically asFigure 4 As shown, assume that terminals A, B, C, D, E, F, G, H, and I make uplink resource requests in a certain time slot. The satellite can respectively form the following according to the measurement of the request signals, as shown in Table 2 below, where ω is defaulted to the time slot to be scheduled currently, and the measured energy lower than the threshold is 0, represented by "-":

[0076] Assume that terminal x is allocated time-frequency resources (i.e., time slot) ω in the beam set The signal used by the terminal to send data is scrambled with parameters related to MMSI, such as the 16-bit MMSI after hashing:

[0077]

[0078] Then the SINR of the signal of terminal x received by the satellite on the system resources (Φ x , ω) can be estimated as:

[0079]

[0080] In this formula (7), Λ is the set of all online terminals.

[0081] The goal of multi-beam resource scheduling is to satisfy the QoS of each terminal's service as much as possible, and at the same time process the current inflow load of the system, that is, service data, as much as possible.

[0082] More specifically, the strategy of this embodiment is to find the largest one according to the priority That is, all terminals in X share the time slot ω and satisfy:

[0083]

[0084] In this formula (8), Γ is the threshold to ensure that the probability of the data being successfully received by the satellite is greater than a certain value (such as 1%).

[0085] When the beam management table is as shown in Table 2, assume that Γ = 0dB, N 0 = -174dBm,. An expected scheduling scheme for the current time slot can be considered as follows, where the unit of S is dBm, and the terminals are arranged from top to bottom in descending order of priority:

[0086] Table 2

[0087] Terminal Beam 1 Beam 2 Beam 3 Beam 4 Beam 5 Beam 6 Beam 7 Terminal B - -171 - - - - - Terminal C - -174 -172 - - - - Terminal E - - - - -171 - - Terminal G - - - - - -174 -174 Terminal D -174 - -174 -174 - - - Terminal A -171 - - - - - - Terminal F - - - - - -169 - Terminal H - - - -171 - - - Terminal I - - - - -165 - -

[0088] For the current time slot ω to be scheduled, design the scheduling scheme for the terminals on the system resources (Φ, ω) in the order of priority in the list in turn:

[0089] ​The data service priority of terminal B is the highest, so resource allocation is carried out preferentially. Terminal B can only be received by beam 2 and can be interfered by terminal C. Assuming that both terminals B and C transmit in the current time slot ω, the SINR received by terminal B on beam 2 is:

[0090]

[0091] Meeting the threshold requirement of Γ = 0dB, so Φ B = {2}.

[0092] According to the beam management list, the priority of terminal C follows that of terminal B. Terminal C can be detected on beam 2 and beam 3. Therefore, it can be interfered by terminal B on beam 2 and by terminal D on beam 3. If terminals B, C, and D all transmit in the current time slot ω, the received SINR of terminal C on beam 2 is:

[0093]

[0094] The received SINR on beam 3 is:

[0095]

[0096] It can be seen that the reception on either beam 2 or beam 3 cannot meet the threshold of Γ = 0dB.

[0097] In this case, the uplink signal of terminal C is jointly received on beam 2 and beam 3, and the received SINR obtained by using the maximum ratio combining scheme is:

[0098]

[0099] Meeting the condition of Γ = 0dB, so, Φ C = {2, 3}.

[0100] Terminal E can only be received by beam 5 and can be interfered by terminal I. Its SINR is:

[0101]

[0102] The priority of terminal I is relatively low. After silencing, the SINR is 3dB, meeting the condition of Γ = 0dB: Φ E = {5}.

[0103] Terminal G can be detected by beam 6 and beam 7. It is not interfered by other terminals on beam 7 and can be interfered by terminal F on beam 3. If terminals G and F both transmit in the current time slot ω, the received SINR of terminal G on beam 7 is:

[0104]

[0105] The received SINR on beam 6 is:

[0106]

[0107] The terminal G uses beam 7 to meet the condition of Γ = 0 dB: Φ E = {7}.

[0108] The terminal D can be detected by beams 1, 3, and 4, and can be interfered by the terminal A in beam 1, by the terminal C in beam 3, and by the terminal H in beam 4. If the terminals C, D, A, and H all transmit in the current time slot ω, the received SINR of the G terminal in beam 1 is:

[0109]

[0110] The received SINR in beam 3 is:

[0111]

[0112] The received SINR in beam 4 is:

[0113]

[0114] In single-beam reception, the SINR cannot meet the condition of Γ = 0 dB. Therefore, the uplink signal of the terminal D is jointly received by beams 1, 3, and 4, and the received SINR is obtained by using the maximum ratio combining scheme:

[0115]

[0116] Meets the requirement of Γ = 0 dB, and its combined beam is Φ D = {1, 3, 4}.

[0117] The situation of the terminal A is similar to that of the terminal B, and the requirement of Γ = 0 dB can be met when receiving in beam 1.

[0118] The terminal F is similar to the terminal B, and the requirement of Γ = 0 dB can be met when receiving in beam 3.

[0119] The terminal H can only be received by beam 4 and can be interfered by the terminal D, and its SINR is 0 dB, meeting the requirement of Γ = 0 dB: Φ F = {4}.

[0120] According to the above analysis of the terminal I, the terminal I is silent in the current time slot ω:

[0121] At this time, the terminals X = {A, B, C, D, E, F, G, H}, through the spatial degrees of freedom provided by Φ, share the time slot ω on the premise of meeting the QoS.

[0122] More specifically, the multi-beam satellite uplink resource management method provided in this embodiment can be completed by a trained artificial intelligence module, and can make expected scheduling decisions in most system cases, that is, while ensuring the QoS of user services, taking into account the maximum possible processing of the input traffic of the system.

[0123] More specifically, Document 1 mentioned in this embodiment is Michael Mao Wang, Jingjing Zhang, and Xiaohu You, “Machine-type communication for maritime Internet of Things: A design,” IEEE Communications: Surveys and Tutorials, vol. 22, no. 4, pp 2550–2585, 2020.

[0124] In summary, the present invention provides a multi-beam satellite uplink resource management method, which not only makes full use of the spatial degrees of freedom provided by multi-beams to increase the efficiency of extremely scarce time-frequency resources, but also ensures the continuity of beam coverage and the uniform consistency of signal quality. Compared with the traditional single beam, it not only improves the system's ability to process input traffic (i.e., expands the system capacity), but more importantly, provides the system with more means to ensure the QoS of user services. By introducing artificial intelligence, most of the resource management complexity can be completed offline, especially in the case of a large number of beams, reducing the online workload, which is particularly suitable for the characteristics of small LEO satellite loads.

[0125] Details not described in the present invention are all well-known techniques in the art.

[0126] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall fall within the protection scope determined by the claims.

Claims

1. A multi-beam satellite uplink resource management method for Internet of Things communication, characterized in that, the method comprises the following steps: Step S1: For a multi-beam satellite communication system, which includes a satellite terminal and multiple user terminals, the user terminal obtains the beam ID from the downlink signal, and the satellite terminal downlink signal is scrambled with corresponding IDs according to different beams; wherein, when a certain user terminal among the multiple user terminals needs to upload resources to the satellite terminal, the user terminal sends an uplink resource request to the satellite terminal, and the user terminal selects the ID of the beam with the strongest signal intensity from the obtained downlink signals of multiple different beams, scrambles the resource request signal, and sends the request signal to the satellite terminal on the resources specified by the system; Step S2: For multiple beams, the satellite terminal selects one of the beams, detects all uplink resource request signals according to the beam ID and records their signal intensities; Step S3: On all beams, the satellite terminal repeats Step S2; Step S4: According to the signal intensity data obtained in Step S2 and Step S3, construct an interference management list, wherein, for this interference management list, the vertical axis is the classification of user terminals, the horizontal axis is the beam classification, or, the vertical axis is the beam classification, the horizontal axis is the user terminal classification, and a threshold value is set, and the signal measurement values lower than this threshold value are set to null; Step S5: According to the interference management list in Step S4 and the user service data information in the scheduler, perform beam resource scheduling for the multiple user terminals, wherein, when performing beam resource scheduling, the following principles need to be followed: satisfy the QoS of each terminal service as much as possible, and at the same time process the current inflow load of the system as much as possible; Step S6: Scramble the uplink signals of user terminals assigned to different beams; In Step S1, when the user terminal sends an uplink resource request to the satellite terminal, the request includes: the size of the data packet. In Step S2, the satellite terminal is on beam φ and on the time-frequency resources specified by the system, and detects all uplink resource request signals with φ as the scrambling code; When the uplink resource request signal of a user terminal x is detected by the satellite terminal on (φ, υ), the signal intensity output by its detector is expressed as the energy per unit resource, as shown in the following formula: In this formula, Ω is the set of system time-frequency resources, is the channel gain of terminal x at (φ, υ), and ρ x is the energy per unit resource of the signal transmitted by terminal x; In Step S5, the expression of satisfying the QoS of each terminal service as much as possible and at the same time processing the current inflow load of the system as much as possible is: Find the largest terminal set in the user terminal set Λ according to the priority Share the time slot ω, and Satisfy: In this formula, represents the SINR of the signal of user terminal x received by the satellite on the system resources (Φ x , ω) when the user terminal x is allocated the time-frequency resource ω ∈ Ω, and Φ x is the set of beams participating in the joint reception of the signal of user terminal x, and Γ is the threshold to ensure that the probability of successful reception of data by the satellite side is greater than a certain value; In Step S6, when performing scrambling, the scrambling is independent of the beam number, but related to the MAC ID of the user terminal.

2. A multi-beam satellite uplink resource management method for Internet of Things communication according to claim 1, characterized in that, in the multi-beam satellite communication system, the signals on different beams are distinguished by different scrambling sequences, and the scrambling sequence is a pseudo-random sequence related to the beam number, wherein, for the downlink signal, the 42-bit mask M is determined according to the following formula: is the mobile communication service identification code in the Internet of Things for maritime affairs; n beam is the identifier of the beam in the multi-beam antenna.

3. A multi-beam satellite uplink resource management method for Internet of Things communication according to claim 2, characterized in that, When there is uplink data, the user terminal uses a specific physical channel to initiate a resource request to the satellite end, where the specific physical channel is a random access channel and uses a pseudo-random sequence associated with the selected beam as the scrambling code of the uplink signal, which is specifically expressed as:

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