Downlink adaptive non-orthogonal multiple access method for star-ground fusion network

Abstract

This invention proposes a downlink adaptive nonorthogonal multiple access method for satellite-ground converged networks. By integrating promising cognitive radio and nonorthogonal multiple access technologies, this invention proposes an adaptive dynamic multiple access technology based on spectrum sharing to match the uneven distribution and time-varying characteristics of service demands and available spectrum resources in ISTCN, thereby improving spectrum utilization and access density.

Description

Technical Field

[0001] This invention belongs to the field of radio technology, and in particular relates to a downlink adaptive nonorthogonal multiple access method for satellite-ground converged networks. Background Technology

[0002] To meet the seamless information service requirements of future 6G networks—global coverage, ubiquitous access, and on-demand service—Integrated Satellite Terrestrial Communication Networks (ISTCNs), by organically integrating the advantages of satellite systems and terrestrial networks, can effectively fulfill these requirements and have become a development trend for future wireless communication systems. However, ISTCNs are typical resource-constrained systems. Faced with the exponential growth in the number of terminals and increasingly fierce competition for wireless communication resources, new multi-access technologies with higher spectrum and energy efficiency, greater connection density, and more flexible access methods are needed. Simultaneously, considering the uneven distribution and time-varying nature of traffic demand in terrestrial cells within ISTCNs, the number of terminals requesting services and available spectrum resources are time-varying in ISTCNs, and a single multiple access method cannot fully utilize valuable spectrum resources. To address these issues, this invention proposes an adaptive dynamic multiple access technology based on spectrum sharing by integrating promising cognitive radio and non-orthogonal multiple access technologies. This technology matches the uneven and time-varying distribution of service demands and available spectrum resources in ISTCNs, improving spectrum utilization and access density. Summary of the Invention

[0003] The purpose of this invention is to address the problems in existing technologies by proposing a downlink adaptive non-orthogonal multiple access method for satellite-terrestrial converged networks. In satellite-terrestrial converged networks, the spatial distribution of traffic demand in terrestrial cells is uneven and time-varying, while the spectrum resources available to satellite terminals are no longer fixed. Considering the uneven distribution and dynamic time-varying characteristics of both demand and resources, an adaptive non-orthogonal multiple access scheme is designed.

[0004] This invention is achieved through the following technical solution: This invention proposes a downlink adaptive non-orthogonal multiple access method for satellite-ground converged networks, the method comprising the following steps:

[0005] Step 1: The satellite control center first analyzes the ground traffic demand within a certain time slot. During this process, the satellite terminal collaboratively captures the status information of the ground terminal in the surrounding environment and detects spectrum holes in real time.

[0006] Step 2: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage of the ground terminal and reports the sensing results to the unified fusion center;

[0007] Step 3: The fusion center analyzes all terminal channels based on the available spectrum resources sensed by the satellite terminals, and allocates the most suitable access channel according to the terminal's service requirements and QoS (Quality of Service).

[0008] Step 4: In the satellite-ground integrated network, the satellite control center and the ground base station cooperate to enable satellite terminals and ground terminals to share the same spectrum resources;

[0009] Step 5: Determine whether the satellite terminal can continue to use the spectrum resources. Assume that the satellite terminal is only temporarily using the spectrum resources of the ground terminal. If the ground terminal wants to resume communication during the data transmission of the satellite terminal, the satellite terminal will switch to another available spectrum resource.

[0010] Step Six: The satellite control center and the ground station jointly select a spectrum sharing mode for non-orthogonal multiple access;

[0011] Step 7: The satellite control center analyzes and determines the overload factor for non-orthogonal multiple access based on the available spectrum resources in the current time slot and the number of terminals requesting access.

[0012] Step 8: The satellite control center determines the number of terminals on each resource block based on the overload factor. ; A user uses a single-layer rate splitting technique to divide their data into shared data. and private data Among them, private data Encoded into data stream , Public data synthesis of individual users Encoded into data stream The total data flow is ;

[0013] Step Nine: The satellite control center uses a precoding matrix For the total data stream Perform linear precoding.

[0014]

[0015] By using the linear precoding matrix Optimize to achieve the best system performance;

[0016] Step 10: Then at the receiving end, the first... The signal received by a user can be represented as:

[0017]

[0018] in, It is the antenna array and user that form the current beam. Channel gain between users; First, treat all privately owned data as interference, and then target the public data stream. Demodulation is performed; at the user Demodulated data stream The SINR is,

[0019]

[0020] Step Eleven: Once It was successfully decoded, and it was used to decode the original received signal. The user's contribution was then deducted, and afterwards... Decoding one's own private data stream by treating other users' private data streams as noise ; in the user Decoding private data streams The SINR is,

[0021]

[0022] user The corresponding public and private data can be represented by the following rates: and ; Actual information transmission rate It should not exceed ,Right now Then the weighted sum rate of all users can be expressed as: .

[0023] Furthermore, the spectrum sharing methods include superimposed spectrum access, underlying spectrum access, and hybrid access.

[0024] Furthermore, using Represents the overload factor, where and These represent the number of time-frequency resource blocks and the number of users, respectively.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) For the satellite-ground integrated network scenario, a non-uniform distribution and time-varying resource model and traffic demand model of ISTCN 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).

[0027] (2) In the scenario of satellite-ground converged network, by combining spectrum sharing and RSMA technology, the number of terminals accessing a time-frequency resource block using RSMA technology can be adaptively adjusted according to the number of satellite terminals and available satellite resources, thereby improving spectrum resource utilization and terminal access density.

[0028] (3) Because the RSMA technology receiver detection algorithm uses a single-layer continuous interference cancellation algorithm, the system complexity increases linearly with the number of terminals. The detection algorithm complexity is significantly lower than other non-orthogonal access technologies. Therefore, the algorithm of this invention has low complexity while improving the system's spectral efficiency and access density. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the architecture of a space-ground integrated network system.

[0030] Figure 2 This is a schematic diagram of adaptive nonorthogonal multiple access based on spectrum sharing.

[0031] Figure 3 For rate splitting User structure system diagram.

[0032] Figure 4 For rate splitting User transmission model diagram.

[0033] Figure 5 This is a graph showing the relationship between downlink system capacity and the average number of terminals per cell. Detailed Implementation

[0034] 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.

[0035] An access system based on the spectrum sharing concept for satellite-ground converged networks, such as Figure 1 As shown, compared to terrestrial networks and satellite systems, ISTCN can better allocate communication resources and improve resource efficiency. Satellite coverage is divided into many cells; each satellite's narrow beam can serve one cell, and multiple satellites collectively serve the ground cells, forming antenna subarrays for each beam. A single antenna. Ground terminals and satellite terminals share the same spectrum resources. The fusion center collects system resource information sensed by the satellite terminals and reports it to the satellite control center for unified allocation. In this invention, considering that ground communication is more convenient and lower in cost than satellite communication, the ground terminal is designated as the primary user and the satellite terminal as the sensing user.

[0036] This invention proposes a downlink adaptive nonorthogonal multiple access method for satellite-ground converged networks, the method comprising the following steps:

[0037] Step 1: The satellite control center first analyzes the ground traffic demand within a certain time slot. During this process, the satellite terminal collaboratively captures the status information of the ground terminal in the surrounding environment and detects spectrum holes in real time.

[0038] Step 2: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage of the ground terminal and reports the sensing results to the unified fusion center;

[0039] Step 3: The fusion center analyzes all terminal channels based on the available spectrum resources sensed by the satellite terminals, and allocates the most suitable access channel according to the terminal's service requirements and communication service quality (QoS).

[0040] Step 4: 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 2 As shown on the right.

[0041] Step 5: Determine whether the satellite terminal can continue to use the spectrum resources. Assume that the satellite terminal is only temporarily using the spectrum resources of the ground terminal. If the ground terminal wants to resume communication during the data transmission of the satellite terminal, the satellite terminal will switch to another available spectrum resource.

[0042] Step Six: The satellite control center and the ground station jointly select a spectrum sharing mode for non-orthogonal multiple access;

[0043] Step Seven: The satellite control center analyzes and determines the overload factor for non-orthogonal multiple access based on the available spectrum resources in the current time slot and the number of terminals requesting access; using... Represents the overload factor, where and These represent the number of time-frequency resource blocks and the number of users, respectively.

[0044] Step 8: The satellite control center determines the number of terminals on each resource block based on the overload factor. Detailed transmission scheme as follows Figure 3 and Figure 4 As shown, A user uses a single-layer rate splitting technique to divide their data into shared data. and private data Among them, private data Encoded into data stream , Public data synthesis of individual users Encoded into data stream The total data flow is ;

[0045] Step Nine: The satellite control center uses a precoding matrix For the total data stream Perform linear precoding.

[0046]

[0047] By using the linear precoding matrix Optimize to achieve the best system performance;

[0048] Step 10: Then at the receiving end, the first... The signal received by a user can be represented as:

[0049]

[0050] in, It is the antenna array and user that form the current beam. Channel gain between users; First, treat all privately owned data as interference, and then target the public data stream. Demodulation is performed; at the user Demodulated data stream The SINR is,

[0051]

[0052] Step Eleven: Once It was successfully decoded, and it was used to decode the original received signal. The user's contribution was then deducted, and afterwards... Decoding one's own private data stream by treating other users' private data streams as noise ; in the user Decoding private data streams The SINR is,

[0053]

[0054] user The corresponding public and private data can be represented by the following rates: and To ensure that all users can successfully decode the public data stream, Actual information transmission rate It should not exceed ,Right now Then the weighted sum rate of all users can be expressed as: .

[0055] Example

[0056] An access system based on the spectrum sharing concept for satellite-ground converged networks, such as Figure 1 As shown, the satellite's coverage area is divided into many cells, and each satellite's narrow beam can serve one cell. The antenna subarray forming each beam consists of... The ground terminal and satellite terminal share the same spectrum resources. Assume 20 satellites serve 240 cells, each satellite activates 4 beams, each beam diameter is 100 km, and the satellite orbital altitude is set to 600 km. The satellite transceiver antenna gain is 30 dB, the transmit power is 10 W, and the total transmit power is evenly distributed among the satellite beams. In ISTCN, the satellite operates at a frequency of 2.4 GHz, with a total bandwidth of 5 MHz and a subcarrier bandwidth of 100 kHz. The satellite terminal transceiver antenna gain has four options: 0 dB, 5 dB, 10 dB, and 15 dB. The number of carriers occupied by the ground terminal in the current time slot follows a uniform distribution on [10, 40].

[0057] The method of this invention is implemented through the following steps:

[0058] Step 1: The satellite control center first analyzes the ground traffic demand within a specific time slot. During this process, satellite terminals collaboratively capture the status information of ground terminals in the surrounding environment and detect spectrum holes in real time. In the centralized collaborative spectrum sensing mode, the satellite terminals report their sensing results to a unified fusion center. In the distributed collaborative spectrum sensing mode, the satellite terminals, acting as the fusion center, exchange sensing results and determine spectrum resource allocation.

[0059] Step Two: Satellite terminals collaboratively capture the status information of ground terminals in the surrounding environment and detect spectrum holes in real time. In the centralized collaborative spectrum sensing mode, the satellite terminal reports its sensing results to a unified fusion center. In the distributed collaborative spectrum sensing mode, the satellite terminal acts as the fusion center, exchanging sensing results and determining spectrum resource allocation.

[0060] Step 3: The fusion center analyzes all terminal channels based on the available spectrum resources sensed by the satellite terminals, and allocates the most suitable access channel according to the terminal's service requirements and communication QoS.

[0061] Step Four: In a space-ground converged network, the satellite control center and ground base stations work together 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 2 As shown on the right.

[0062] Step 5: Determine if the satellite terminal can continue to use the spectrum resources. Assuming the satellite terminal is only temporarily using the ground terminal's spectrum resources, if the ground terminal wants to resume communication during the satellite terminal's data transmission, the satellite terminal will have to switch to another available spectrum resource.

[0063] Step Six: The satellite control center and the ground station jointly select a spectrum sharing mode for non-orthogonal multiple access.

[0064] Step 7: The satellite control center analyzes and determines the overload factor for non-orthogonal multiple access based on the available spectrum resources in the current time slot and the number of terminals requesting access. For simplicity, we use... Represents the overload factor, where and These represent the number of time-frequency resource blocks and the number of users, respectively.

[0065] Step 8: The satellite control center determines the number of terminals on each resource block based on the overload factor. Detailed transmission scheme as follows: Figure 3 and Figure 4 As shown. A user uses a single-layer rate splitting technique to divide their data into shared data. and private data Private data Encoded into data stream , Public data synthesis of individual users Encoded into data stream The total data flow is .

[0066] Step 9: Then, the satellite control center uses a precoding matrix. For the total data stream Perform linear precoding.

[0067]

[0068] By using the linear precoding matrix Optimize to achieve the best system performance.

[0069] Step 10: Then at the receiving end, the first... The signal received by a user can be represented as:

[0070]

[0071] user First, treat all privately owned data as interference, and then target the public data stream. Demodulation is performed. (At the user's...) Demodulated data stream The SINR is,

[0072]

[0073] Step Eleven: Once It was successfully decoded, and it was used to decode the original received signal. The user's contribution was then deducted. Afterwards, the user... Decoding one's own private data stream by treating other users' private data streams as noise In the user Decoding private data streams The SINR is,

[0074]

[0075] user The corresponding public and private data can be represented by the following rates: and It should be noted that, in order to ensure that all users can successfully decode the public data stream, Actual information transmission rate It should not exceed ,Right now Then the weighted sum rate of all users can be expressed as: .

[0076] Figure 5 Simulations were conducted to compare the adaptive non-orthogonal multiple access (NOA) and orthogonal multiple access (OMA) methods in a downlink system. It can be seen that, under the same simulation parameters, the performance of the adaptive NOA method is superior to that of the OMA method. As the number of terminal users increases, the advantages of the adaptive NOA method over the OMA method become more pronounced. This is because, with the increasing number of terminals, limited by the available spectrum resources of satellite terminals, excess users in the OMA scheme will be unable to access the communication system, while the adaptive NOA scheme can still continue to provide access for these excess users.

Claims

1. A downlink adaptive non-orthogonal multiple access method for satellite-ground converged networks, characterized in that: The method includes the following steps: Step 1: The satellite control center first analyzes the ground traffic demand within a certain time slot. During this process, the satellite terminal collaboratively captures the status information of the ground terminal in the surrounding environment and detects spectrum holes in real time. Step 2: In the centralized collaborative spectrum sensing mode, the satellite terminal obtains the spectrum usage of the ground terminal and reports the sensing results to the unified fusion center; Step 3: The fusion center analyzes all terminal channels based on the available spectrum resources sensed by the satellite terminals, and allocates the most suitable access channel according to the terminal's service requirements and QoS (Quality of Service). Step 4: In the satellite-ground integrated network, the satellite control center and the ground base station cooperate to enable satellite terminals and ground terminals to share the same spectrum resources; Step 5: Determine whether the satellite terminal can continue to use the spectrum resources. Assume that the satellite terminal is only temporarily using the spectrum resources of the ground terminal. If the ground terminal wants to resume communication during the data transmission of the satellite terminal, the satellite terminal will switch to another available spectrum resource. Step Six: The satellite control center and the ground station jointly select a spectrum sharing mode for non-orthogonal multiple access; Step 7: The satellite control center analyzes and determines the overload factor for non-orthogonal multiple access based on the available spectrum resources in the current time slot and the number of terminals requesting access. Step 8: The satellite control center determines the number of terminals on each resource block based on the overload factor. ; A user uses a single-layer rate splitting technique to divide their data into shared data. and private data Among them, private data Encoded into data stream , Public data synthesis of individual users Encoded into data stream The total data flow is ; Step Nine: The satellite control center uses a precoding matrix For the total data stream Perform linear precoding. By using the linear precoding matrix Optimize to achieve the best system performance; Step 10: Then at the receiving end, the... The signal received by a user can be represented as: in, It is the antenna array and user that form the current beam. Channel gain between users; First, treat all privately owned data as interference, and then target the public data stream. Demodulation is performed; at the user Demodulated data stream The SINR is, Step Eleven: Once It was successfully decoded, and it was used to decode the original received signal. The user's contribution was then deducted, and afterwards... Decoding one's own private data stream by treating other users' private data streams as noise ; in the user Decoding private data streams The SINR is, user The corresponding public and private data can be represented by the following rates: and ; Actual information transmission rate It should not exceed ,Right now Then the weighted sum rate of all users can be expressed as: .

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

3. The method according to claim 1, characterized in that, use Represents the overload factor, where and These represent the number of time-frequency resource blocks and the number of users, respectively.

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