Multi-beam satellite hopping beam method based on spectrum sharing for satellite-ground integrated networks

Abstract

This invention proposes a multi-beam satellite beam-hopping method based on spectrum sharing for satellite-terrestrial converged networks. In satellite-terrestrial converged networks, the traffic demand of terrestrial cells changes dynamically in both space and time. Simultaneously, since the satellite network and the terrestrial network share the same spectrum resources, the spectrum resources available to satellite terminals are no longer fixed. This invention introduces spectrum sharing to assist in the design of beam-hopping schemes, adapting to the simultaneous changes in traffic demand and available spectrum resources in the spatiotemporal dimensions. The proposed spectrum-sharing-based beam-hopping algorithm can reduce multiple access interference and improve system reliability to a certain extent.

Description

Technical Field

[0001] This invention belongs to the field of radio technology, and in particular relates to a multi-beam satellite hopping beam method based on spectrum sharing for satellite-ground converged networks. Background Technology

[0002] To meet the demands for seamless global coverage and ubiquitous access, integrating satellite communication systems with terrestrial communication networks to form a unified space-ground communication network has become a development trend in wireless communication systems. To better utilize satellite resources, satellite multi-beam technology has been widely applied in integrated space-ground networks. Multi-beam satellites utilize precoding technology to simply and efficiently generate multiple small-coverage, high-gain spot beams, greatly enhancing the channel capacity and service quality of point-to-point communication links. Furthermore, multi-beam satellites introduce frequency reuse and polarization reuse technologies between spot beams, providing service beams with different frequencies and polarizations to adjacent beam cells, reducing co-channel interference between beams, and improving service quality while achieving full beam coverage. Further, considering the uneven distribution and time-varying nature of traffic demand in terrestrial cells within integrated space-ground networks, beam hopping technology has been introduced as a promising approach. However, integrated space-ground networks allow terrestrial and satellite terminals to share the same spectrum resources, and the available spectrum resources for the satellite system need to be adjusted in real-time based on the resources already occupied by the terrestrial network. Existing beam scheduling algorithms typically allocate satellite beams based on terminal needs, ignoring the dynamic changes in available satellite spectrum resources. This makes them unsuitable for scenarios where both demand and dynamics change rapidly. Therefore, it is necessary to explore new beam-hopping methods to adapt to the new scenario of dynamically changing spectrum resources and traffic demands in space-ground converged networks. Summary of the Invention

[0003] The purpose of this invention is to address the problems in existing technologies by proposing a multi-beam satellite beam-hopping method based on spectrum sharing for satellite-terrestrial converged networks. In satellite-terrestrial converged networks, the traffic demand of terrestrial cells changes dynamically in both space and time. Simultaneously, since the satellite network and the terrestrial network share the same spectrum resources, the spectrum resources available to satellite terminals are no longer fixed. This invention introduces spectrum sharing to assist in the design of beam-hopping schemes, adapting to the simultaneous changes in traffic demand and available spectrum resources in both space and time.

[0004] This invention is achieved through the following technical solution: This invention proposes a multi-beam satellite hopping beam method based on spectrum sharing for satellite-ground integrated networks, the method comprising the following steps:

[0005] Step 1: The satellite control center first analyzes the traffic demand of N ground-based beam cells within a certain time slot. It is assumed that the satellite knows the service distribution T of each ground cell in the current time slot through the control channel. 1× N ={T1,T2,…T n ,…T N}, where T n This represents the number of terminals requesting access to the nth cell; the number of terminals accessing a cell represents the cell's traffic demand.

[0006] Step 2: The terrestrial network and the satellite network share the same spectrum resources. The satellite terminal collaboratively captures the status information of the terrestrial terminal in the surrounding environment and detects spectrum holes in real time.

[0007] Step 3: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage information of the ground terminal and reports the sensing results to the unified fusion center. The number of available carriers for the ground cell in the current time slot is denoted as C. 1×N ={C1,C2,…C n ,…C N};

[0008] Step 4: Within a time slot, the satellite control center comprehensively analyzes the traffic demand of the ground cells and the available spectrum resources in the current time slot, and allocates appropriate beams to serve the ground cells. Each satellite narrow beam can serve one cell. The satellite beams adopt a time-division multiplexing mode, and each time slot activates part of the beams to serve part of the ground cells.

[0009] Step 5: In the next time slot, the satellite control center will adjust the beam allocation strategy according to changes in spectrum resources and terminal requirements;

[0010] Step Six: In the space-ground converged network, the satellite control center and ground base stations cooperate to enable satellite terminals and ground terminals to share the same spectrum resources;

[0011] Step 7: After the satellite control center allocates beams to ground cells based on traffic demand and available resources, the satellite terminals in the covered cells need to access the satellite network to complete communication. The satellite terminals use power-domain non-orthogonal multiple access (NOMA). Taking a two-user NOMA downlink as an example, after setting appropriate power configuration factors a1 and a2, the satellite, as the signal transmitter, transmits a time-frequency superimposed signal to user 1 and user 2. The signal is represented as follows:

[0012]

[0013] Therefore, the received signal from the ground terminal is represented as follows:

[0014] y1 = h1x + n1,

[0015] y2=h2x+n2,

[0016] Where h1 and h2 are the channels, and n1 and n2 are the additive white noise of the channels: and According to the power domain NOMA power allocation principle, SIC is implemented at the receiver. The power allocated to users with weak channel conditions at the transmitter is higher than that for users with strong channel conditions, i.e., a1 < a2.

[0017] Step 8: In the downlink, the user acts as the signal receiver, equipped with SIC processing capabilities. User 1, due to favorable channel conditions, first demodulates the high-power signal from User 2, reconstructs and eliminates the User 2 signal, then demodulates and extracts the User 1 signal. User 2, due to poor channel conditions, directly treats the User 1 signal as noise and extracts its own signal. After User 1 successfully demodulates, reconstructs, and eliminates the User 2 signal (i.e., completes SIC processing), the user communication capacities are respectively...

[0018]

[0019]

[0020] Furthermore, the spectrum sharing methods include superimposed spectrum access, underlying spectrum access, and hybrid access.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) For the satellite-ground integrated network scenario, a non-uniform distribution and time-varying resource model and traffic demand model of the satellite-ground integrated network were established, in which the ground terminal is regarded as the primary user and the satellite terminal is regarded as the secondary user (sensing terminal).

[0023] (2) In the context of a space-ground converged network, a beam-hopping scheme based on spectrum sharing and beam-hopping technology is designed, taking into account both the access needs of ground cells and the availability of satellite resources, to improve spectrum resource utilization and terminal access density. This overcomes the shortcomings of traditional beam-hopping schemes, which only consider the needs of ground cells and ignore the availability of spectrum resources, which is also subject to spatiotemporal variations.

[0024] (3) Beam scheduling algorithms take into account available spectrum resources. In scenarios with active ground terminal communication, available spectrum resources are often limited, and satellite beams generally avoid such cells, thus reducing communication interference. Therefore, beam hopping algorithms based on spectrum sharing can reduce system multiple access interference to a certain extent and improve system reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the architecture of a space-ground integrated network system.

[0026] Figure 2 This is a schematic diagram of hopping beam technology based on spectrum sharing.

[0027] Figure 3This is a schematic diagram of adaptive nonorthogonal multiple access based on spectrum sharing.

[0028] Figure 4 This is a schematic diagram of a two-user power NOMA scheme.

[0029] Figure 5 This is a graph showing the relationship between uplink system capacity and the average number of terminals per cell.

[0030] Figure 6 This is a graph showing the relationship between downlink system capacity and the average number of terminals per cell. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] A hopping beam multi-beam satellite system based on spectrum sharing for satellite-ground integrated networks, such as Figure 1 As shown, compared to a single communication network system (terrestrial communication network or satellite communication network), a space-ground integrated network can allocate communication resources more efficiently and improve resource efficiency through unified resource allocation. In this invention, considering that terrestrial communication is more convenient and less expensive than satellite communication, the terrestrial terminal (the terminal communicating with the base station) is designated as the primary user, and the satellite terminal (the terminal communicating with the satellite) is designated as the sensing user.

[0033] This invention proposes a multi-beam satellite beam-hopping method based on spectrum sharing for satellite-ground integrated networks. The method includes the following steps:

[0034] Step 1: The satellite control center first analyzes the traffic demand of N ground-based beam cells within a certain time slot. It is assumed that the satellite knows the service distribution T of each ground cell in the current time slot through the control channel. 1×N ={T1,T2,…T n ,…T N}, where T n This represents the number of terminals requesting access to the nth cell; the number of terminals accessing a cell represents the cell's traffic demand.

[0035] Step Two: Because terrestrial and satellite networks share the same spectrum resources, in addition to knowing the cell's traffic demand, it is also necessary to know the spectrum resources available to the satellite terminal to guide the beam scheduling algorithm. During this process, the satellite terminal collaboratively captures the status information of terrestrial terminals in the surrounding environment and detects spectrum holes in real time.

[0036] Step 3: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage information of the ground terminal and reports the sensing results to the unified fusion center. The number of available carriers for the ground cell in the current time slot is denoted as C. 1×N ={C1,C2,…C n ,…C N};

[0037] Step 4: Within a time slot, the satellite control center comprehensively analyzes the traffic demand of the ground cells and the available spectrum resources in the current time slot, and allocates appropriate beams to serve the ground cells, such as... Figure 2 As shown, each satellite's narrow beam can serve one cell. The satellite beams use a time-division multiplexing mode, with each time slot activating a portion of the beam to serve a portion of the ground cells; from Figure 2 As can be seen, user traffic demand is unevenly distributed spatially and changes dynamically over time. Furthermore, the busy spectrum resources and the available idle spectrum resources are also different in each satellite beam.

[0038] Step 5: In the next time slot, the satellite control center will adjust the beam allocation strategy according to changes in spectrum resources and terminal requirements;

[0039] Step Six: In a space-ground converged network, the satellite control center and ground base stations collaborate to enable satellite terminals and ground terminals to share the same spectrum resources. Common spectrum sharing methods include overlay spectrum access, underlying spectrum access, and hybrid access, such as... Figure 3 As shown on the right, the present invention employs a superimposed spectrum sharing mode;

[0040] Step 7: After the satellite control center allocates beams to ground cells based on traffic demand and available resources, the satellite terminals in the beam-covered cells need to access the satellite network to complete communication. To improve spectrum efficiency and access density, satellite terminals use power-domain non-orthogonal multiple access (NOMA). Taking a two-user NOMA downlink as an example, ... Figure 4 As shown, after setting appropriate power configuration factors a1 and a2, the satellite, acting as the signal transmitter, transmits a time-frequency domain superimposed signal to users 1 and 2. The signal is represented as follows:

[0041]

[0042] Therefore, the received signal from the ground terminal is represented as follows:

[0043] y1 = h1x + n1,

[0044] y2=h2x+n2,

[0045] Where h1 and h2 are the channels, and n1 and n2 are the additive white noise of the channels: and According to the principle of power allocation in the power domain NOMA, in order to ensure system fairness, SIC is implemented at the receiver. The power allocated to users with weak channel conditions at the transmitter is higher than that allocated to users with strong channel conditions, i.e., a1 < a2.

[0046] Step 8: In the downlink, the user acts as the signal receiver, equipped with SIC processing capabilities. User 1, due to favorable channel conditions, first demodulates the high-power signal from User 2, reconstructs and eliminates the User 2 signal, then demodulates and extracts the User 1 signal. User 2, due to poor channel conditions, directly treats the User 1 signal as noise and extracts its own signal. After User 1 successfully demodulates, reconstructs, and eliminates the User 2 signal (i.e., completes SIC processing), the user communication capacities are respectively...

[0047]

[0048]

[0049] Example

[0050] A multi-beam satellite hopping beam system based on spectrum sharing for space-ground integrated networks, such as Figure 1 As shown, the satellite coverage area is divided into many cells, and each satellite's narrow beam can serve one cell. The ground terminal and the satellite terminal share the same spectrum resources. Assuming 20 satellites serve 240 cells, each satellite can activate a maximum of 12 beams. The satellite transceiver antenna gain is 30dB, the transmit power is 10W, and the total transmit power is evenly distributed by the active beams. In the satellite-ground fusion network, the satellite operates at a frequency of 2.4GHz, with a total bandwidth of 5MHz and a subcarrier bandwidth of 100kHz. The satellite terminal transmit power is set to 20mW, and the transceiver antenna gain has four options: 0dB, 5dB, 10dB, and 15dB. In the beam-hopping scheme, one satellite activates 4 beams in one time slot. The number of carriers occupied by the ground terminal in the current time slot follows a uniform distribution on [10, 30].

[0051] The method of this invention is implemented through the following steps:

[0052] Step 1: The satellite control center will first analyze the ground traffic demand within a specific time slot. Assume the satellite knows the service distribution T of each ground cell in the current time slot via the control channel. 1×N ={T1,T2,…T n ,…T N}, where T n This represents the number of terminals requesting access to the nth cell;

[0053] Step Two: Knowing the cell's traffic demand, it's also necessary to know the available spectrum resources for the satellite terminal. During this process, the satellite terminal collaboratively captures the status information of ground terminals in the surrounding environment and detects spectrum holes in real time.

[0054] Step 3: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage information of the ground terminal and reports the sensing results to the unified fusion center. The number of available carriers for the current time slot ground cell is denoted as C. 1×N ={C1,C2,…C n ,…C N}

[0055] Step 4: Within a time slot, the satellite control center comprehensively analyzes the traffic demand of the ground cells and the available spectrum resources in the current time slot, and allocates appropriate beams to serve the ground cells, such as... Figure 2 As shown. Each satellite's narrow beam can serve one cell. The satellite beams use a time-division multiplexing mode, with each time slot activating a portion of the beam to serve a portion of the ground cells. From Figure 2 As can be seen, user traffic demand is unevenly distributed spatially and changes dynamically over time. Furthermore, the busy spectrum resources and the available idle spectrum resources are also different in each satellite beam.

[0056] Step 5: In the next time slot, the satellite control center will adjust the beam allocation strategy according to changes in spectrum resources and terminal requirements.

[0057] Step Six: In the satellite-ground integrated network, the satellite control center and ground base stations cooperate to enable satellite terminals and ground terminals to share the same spectrum resources. This invention employs a superimposed spectrum sharing mode, such as... Figure 3 As shown.

[0058] Step 7: Considering the received signal quality and the complexity of the detection algorithm, this invention adopts a two-user power domain NOMA access scheme. Taking a two-user NOMA downlink as an example, as follows... Figure 4 As shown, after setting appropriate power configuration factors a1 and a2, the satellite, acting as the signal transmitter, transmits a time-frequency domain superimposed signal to users 1 and 2. The signal is represented as follows:

[0059]

[0060] Therefore, the received signal from the ground terminal is represented as follows:

[0061] y1 = h1x + n1,

[0062] y2=h2x+n2,

[0063] Where h1 and h2 are the channels, and n1 and n2 are the additive white noise of the channels: and According to the power domain NOMA power allocation principle, in order to ensure system fairness, SIC is implemented at the receiver. The power allocated to users with weak channel conditions at the transmitter is higher than that allocated to users with strong channel conditions, i.e., a1 < a2.

[0064] Step 8: In the downlink, the user acts as the signal receiver, possessing SIC processing capabilities. User 1, due to better channel conditions, first demodulates the signal from User 2, which has higher power, then reconstructs and eliminates the User 2 signal, demodulates and extracts the User 1 signal. User 2, due to poorer channel conditions, directly treats the User 1 signal as noise and extracts its own signal. After User 1 successfully demodulates, reconstructs, and eliminates the User 2 signal (i.e., completes SIC processing), the user communication capacities are respectively...

[0065]

[0066]

[0067] Figure 5 The uplink system capacity was simulated to verify the superiority of the spectrum-sharing-based beam hopping algorithm. This invention analyzes the performance of two beam scheduling schemes: spectrum-sharing-based beam hopping and conventional beam hopping. As shown in the figures, under the same access method, spectrum-sharing-based beam hopping always outperforms conventional beam hopping. This is because spectrum-sharing-based beam hopping considers both terminal demand and available spectrum resources, making it more suitable for space-ground converged networks where both demand and resources are dynamic and time-varying. In contrast, conventional beam hopping technology only considers demand and ignores information about available resources. This invention also compares the power domain NOMA access scheme and frequency division multiplexing (FDM) access. It can be seen that when the number of terminals is small, FDM access is better because with fewer terminals and sufficient spectrum resources, FDM utilizes more resources. When the number of terminals increases to a certain value, the system capacity corresponding to power domain NOMA technology will exceed that of DFM technology. This is because with the increase in the number of terminals, NOMA can access more terminals with higher system information transmission rates on limited spectrum resources. In today's world, spectrum resources are scarce and highly competitive, and this non-orthogonal mode often has a higher resource utilization rate.

[0068] Figure 6 The downlink system capacity was simulated, and the trend of system capacity change was compared with... Figure 5Similarly, among the three access methods, ADMA has the largest downlink system capacity. Furthermore, the combined BH and ADMA algorithm based on CR significantly outperforms other methods. Compared to uplink system capacity, under the same access technology and beam scheduling scheme, downlink system capacity is greater.

Claims

1. A multi-beam satellite beam-hopping method based on spectrum sharing for space-ground integrated networks, characterized by: The method includes the following steps: Step 1: The satellite control center first analyzes the ground within a specific time slot. N The traffic demand of each beam cell is assumed to be known by the satellite via the control channel as T, where the traffic distribution of each ground cell in the current time slot is known. 1×N = { T 1, T 2,… T n ,… T N },in T n Indicates the first n The number of terminals requesting access in a cell; the number of terminals accessing a cell represents the cell's traffic demand. Step 2: The terrestrial network and the satellite network share the same spectrum resources. The satellite terminal collaboratively captures the status information of the terrestrial terminal in the surrounding environment and detects spectrum holes in real time. Step 3: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage information of the ground terminal and reports the sensing results to the unified fusion center. The number of available carriers for the ground cell in the current time slot is denoted as C. 1×N = { C 1, C 2,… C n ,… C N }; Step 4: Within a time slot, the satellite control center comprehensively analyzes the traffic demand of the ground cells and the available spectrum resources in the current time slot, and allocates appropriate beams to serve the ground cells. Each satellite narrow beam can serve one cell. The satellite beams adopt a time-division multiplexing mode, and each time slot activates part of the beams to serve part of the ground cells. Step 5: In the next time slot, the satellite control center will adjust the beam allocation strategy according to changes in spectrum resources and terminal requirements; Step Six: In the space-ground converged network, the satellite control center and ground base stations cooperate to enable satellite terminals and ground terminals to share the same spectrum resources; Step 7: After the satellite control center allocates beams to ground cells based on traffic demand and available resources, the satellite terminals in the covered cells need to access the satellite network to complete communication; the satellite terminals use power domain non-orthogonal multiple access (NOMA); the downlink is a two-user NOMA, and the satellite, as the signal transmitter, is configured with an appropriate power configuration factor. a 1. a After step 2, a time-frequency domain superimposed signal is transmitted to both user 1 and user 2. The signal is represented as follows: Therefore, the received signal from the ground terminal is represented as follows: in, and These represent the transmission data of user 1 and user 2, respectively; , For the channel, , Additive white noise for the channel: , ,and ;in and To account for noise power, based on the principle of power allocation in the power domain (NOMA), SiC is implemented at the receiver. The transmitter allocates higher power to users with weak channel conditions than to users with strong channel conditions. ; Step 8: In the downlink, the user acts as a signal receiver with SIC processing capabilities. User 1, due to channel limitations... Under favorable conditions, the signal from user 2, which has high power, is demodulated first. After reconstruction, the signal from user 2 is eliminated, and then the signal from user 1 is demodulated and extracted. Because user 2 has poor channel conditions, the signal from user 1 is directly treated as noise, and its own signal is extracted. After user 1 successfully demodulates, reconstructs, and eliminates the signal from user 2 (i.e., after completing the SIC process), the user communication capacities are as follows:

2. The method according to claim 1, characterized in that, The spectrum sharing methods include superimposed spectrum access, underlying spectrum access, and hybrid access.

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