A space-based heterogeneous multi-link networking selection transmission method

Abstract

The application provides a space-based heterogeneous multi-link networking selection transmission method, which comprises the following steps: step one, user terminal networking; step two, link quality estimation: the user terminal and the satellite periodically count the data volume of the transceiver, and estimate the communication quality of each transmission link in combination with the link load and the packet loss rate; step three, link selection; step four, link switching: in the service communication, the sending end decides the communication link switching by using the cumulative sum control chart technique according to the link state, so as to ensure that the service data is always transmitted through the optimal link; and step five, satellite protocol conversion: the satellite converts the protocols of various communication link frames into unified network layer data packets through address mapping, so as to realize the hinged communication of the multiple heterogeneous links by the routing of the IPv4 unified service data packets. The method of the application realizes the heterogeneous terminal networking by uniformly taking IP as the data bearing on the satellite, realizes the link optimization by using the link quality estimation and the control chart technique, and improves the flexibility and efficiency of the satellite communication.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of satellite networking communication, and relates to space-based heterogeneous multi-link networking, in particular to a space-based heterogeneous multi-link networking selection transmission method. BACKGROUND

[0002] With the iterative development of satellite communication technology and the independent construction of different user systems, the types of communication terminals of each system are various and complex, and multiple communication devices are often configured on the satellite. Due to policy, technology, history and other reasons, there are system barriers between different systems, and even between subsystems of the same satellite, which cannot be flexibly interconnected, resulting in low communication efficiency and rigid use mode. In addition, different types of communication devices use different link communication characteristics, such as Ka and Ku high-frequency communication with high speed but susceptible to environmental interference such as rain and snow; low-frequency communication with wide coverage but low communication speed. According to the real-time space electronic environment, how to flexibly and autonomously select and switch appropriate links as needed is a problem faced by users when using satellite communication. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide a space-based heterogeneous multi-link networking selection transmission method to solve the technical problem that the flexibility and efficiency of the space-based heterogeneous multi-link networking in the prior art need to be further improved.

[0004] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0005] A space-based heterogeneous multi-link networking selection transmission method, which is performed according to the following steps:

[0006] Step 1: User terminal access to network

[0007] The user terminal accesses the satellite network through a multi-type heterogeneous system communication transceiver, and saves the mapping information of the communication transceiver station address and the IP address used by the user terminal on the satellite.

[0008] Step 2: Link quality estimation

[0009] The user terminal and the satellite periodically count the data volume of the communication transceiver, and estimate the communication quality of each sending link in combination with the link load and the packet loss rate.

[0010] The estimation of the communication quality of each sending link includes the estimation of the uplink business communication link quality on the user terminal and the estimation of the downlink quality of the satellite business transmission.

[0011] Step 3: Link selection

[0012] In the business communication, the sending end selects the optimal link for communication according to the link quality estimation obtained in step 2.

[0013] Step four, link switching:

[0014] In the service communication, the sending end decides the communication link switching through the link state using the cumulative sum and control chart technology, so as to ensure that the service data is always transmitted through the optimal link.

[0015] The communication link switching includes the link switching of the uplink data transmission of the user terminal and the link switching of the downlink data transmission of the satellite.

[0016] Step five, satellite protocol conversion:

[0017] The satellite performs protocol conversion on various communication link frames to unified network layer data packets through address mapping, so as to realize the hinged communication of multiple heterogeneous links through the routing of the IPv4 unified service data packets.

[0018] The protocol conversion process includes a framing process and a deframing process, and the deframing process is opposite to the framing process.

[0019] Compared with the prior art, the present application has the following technical effects:

[0020] (I) The method of the present application realizes the networking of heterogeneous terminals by uniformly carrying data in IP on the satellite, realizes link optimization by using link quality estimation and control chart technology, and improves the flexibility and efficiency of satellite communication.

[0021] (II) The method of the present application is different from the independent use of each communication unit in the prior art, and the inconsistent protocol systems lead to rigid user usage and low resource utilization. The present application uses address mapping on the satellite to construct IPv4 datagrams from the link layer to realize unified carrying for routing exchange, and realizes the connectivity between heterogeneous satellite communication terminals.

[0022] (III) In the traditional network, routing is performed based on network layer parameters such as hop count and delay. Multi-path routing research focuses on network layer path selection and does not pay attention to link layer and physical layer capabilities. The method of the present application combines the transmission capabilities of the link layer, estimates the link transmission quality by considering the link load and packet loss rate through low-cost packet number statistics interaction, selects the link with the best transmission quality in multi-link satellite-ground data transmission, improves the transmission efficiency, reduces the probability of satellite-ground communication congestion, and improves the spectrum utilization rate.

[0023] (IV) Unlike the packet retransmission, waiting and other processing schemes in the traditional IP network, the method of the present application monitors the communication situation by using the cumulative sum and control chart method, can quickly detect the deterioration of the communication link to avoid the mis-detection caused by the link quality jitter, and can perform link switching without causing switching oscillation, so as to ensure the transmission quality and efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The working flow diagram of the space-based heterogeneous networking multi-link selection transmission method in the embodiment is shown.

[0025] Figure 2 The working scene diagram of the space-based heterogeneous networking multi-link selection transmission method in the application example is shown.

[0026] The specific content of the application is further explained in detail in combination with the embodiments. DETAILED DESCRIPTION

[0027] It should be noted that all the devices and technologies in the application, if not specially stated, all adopt the devices and technologies known in the prior art.

[0028] To realize the hinge communication of heterogeneous terminals, the real-time switching of multi-links and improve the system utilization, the application provides a space-based heterogeneous multi-link networking selection transmission method. A user configures multiple communication terminals to access a satellite for communication in different systems, a satellite node performs protocol conversion, an IP is uniformly carried for switching routing to realize heterogeneous terminal networking and hinge; the link load and the packet loss rate are considered to estimate the quality of each link with very low overhead to evaluate the link transmission performance; the communication quality change of different links is perceived through the control chart technology, and the link with good communication quality is selected from the available multi-links for service transmission. The application is aimed at various customized communication systems in the development process of satellite communication and the efficient hinge communication demand of a large number of heterogeneous terminals. The application realizes uniform carrying of heterogeneous networking through on-board protocol conversion, performs routing communication based on link quality evaluation, uses the cumulative sum chart to decide link switching and improves the service transmission efficiency. The application belongs to the field of satellite communication networking communication.

[0029] The specific embodiments of the application are given below. It should be noted that the application is not limited to the following specific embodiments, and any equivalent transformation made on the basis of the technical scheme of the application falls within the protection scope of the application.

[0030] Embodiment:

[0031] The embodiment gives a space-based heterogeneous multi-link networking selection transmission method. As shown in the figure, the method is performed according to the following steps: Figure 1

[0032] Step one, user terminal network access:

[0033] The user terminal accesses the satellite network through a plurality of heterogeneous system communication transceivers, and the mapping information of the communication transceiver station address and the IP address used by the user terminal is saved on the satellite.

[0034] In step one, the expression of the communication transceiver is: Tr={tr n |1≤n≤N}. ​

[0035] In the formula:

[0036] Tr represents the set of transceivers;

[0037] N represents the type of transceiver;

[0038] n represents the type number of the transceiver.

[0039] In the communication system used by the nth type of transceiver, the design rate of the satellite-to-user terminal wireless link is: The design speed of the user terminal to satellite wireless link is: The bit error rate of the satellite-to-user terminal wireless link is The bit error rate of the user terminal to satellite wireless link is The specified frame length is l n .

[0040] The theoretical packet error rate for the uplink communication of the nth type of transceiver is... The theoretical packet error rate for downlink communication of the nth type of transceiver is

[0041] Then satellite s i Load configuration as Access satellites i User terminal u j Configure the communication transceiver as

[0042] In step one, the process of accessing the satellite network is as follows: User terminal u j Select an available communication transceiver and access it via satellite. i Send the address of the available communication transceiver site to the ground network management center. and Exclusion Application for network access using external identity authentication information.

[0043] The satellite relays this network access request to the ground network management center, which then assigns a usable IPv4 address. Give user terminal u j and this IPv4 address A reply is sent to the user terminal via the network access reply method. j This indicates successful network access.

[0044] When the satellite relays the network access reply, it records the user terminal's current IPv4 address. With site address mapping relationship

[0045] in:

[0046] Indicates user terminal u j Configured communication transceiver The site address;

[0047] This represents the initial downlink quality value, i.e., the error-free downlink packet rate when the link is normal.

[0048] Step 2, Link Quality Estimation:

[0049] The user terminal and satellite periodically count the amount of data transmitted and received by the communication transceiver. Combined with the link load and packet loss rate, the communication quality of each transmission link is estimated to evaluate the link communication capability.

[0050] In step two, the communication quality of each transmission link is estimated, including the uplink communication link quality estimation for user terminals and the downlink quality estimation for satellite service transmission.

[0051] In step two, the specific method for estimating the quality of the uplink communication link on the user terminal is as follows:

[0052] User terminal u j via satellite i To the user terminal u j When an external user terminal sends data, it selects the transceiver with the best current communication quality based on the current statistical estimate of the transceiver link quality, i.e., the one with the highest estimated link quality. The communication transceiver transmits signals to the satellite. i Send data.

[0053]

[0054] In the formula:

[0055] For communication transceivers The maximum link quality estimate of uplink communication quality at time t;

[0056] For communication transceivers Design value for uplink communication rate;

[0057] T represents the statistical period;

[0058] For user terminal u j The communication transceiver within the current statistical period obtained at time t. Uplink data packet statistics;

[0059] For user terminal u jThe communication transceiver within the current statistical period obtained at time t. Estimated uplink packet error rate.

[0060] In step two, further... Statistical methods and The estimation method is as follows: satellite s i Record the communication between each transceiver and the user terminal u within each period t. j Sending and receiving from user terminal u j Number of data packets received and User terminal u j Record the communication transceiver's communication signal to satellite s within each period t. i Sending and receiving from satellites i Number of data packets received and satellites i and user terminal u j At the end of each statistical period t, the received statistical values ​​will be collected. and Each data packet is sent to the other end of the communication network to inform it of the number of data packets it has received; user terminal u j Estimate the uplink data packet transmission success rate for each transceiver. When there is no uplink data communication At this moment, I will remember.

[0061]

[0062] In step two, the specific method for estimating the downlink quality of satellite service transmission is as follows:

[0063] satellites i Each transceiver to the user terminal j The estimated downlink packet error rate is When there is no downlink data communication At this moment, I will remember. The calculated satellite downlink quality estimate And modify the user terminal communication transceiver site address corresponding to the satellite downlink quality estimate. Link quality estimates in the on-board address mapping table

[0064] Step 3, Link Selection:

[0065] In business communication, the sending end selects the optimal link for communication based on the link quality estimate obtained in step two.

[0066] Link selection includes the selection of uplink communication links for user terminals and the selection of downlink links for satellite service transmission.

[0067] In step three, specifically, the method for selecting the uplink communication link for the user terminal is as follows: User terminal u j via satellite i To the user terminal u j When an external user terminal sends data, it selects the transceiver with the best current communication quality based on the current statistical estimate of the transceiver link quality, i.e., the one with the highest estimated link quality. The communication transceiver transmits signals to the satellite. i Send data.

[0068] In step three, specifically, the method for selecting the downlink for satellite service transmission is as follows: For each IPv4 data packet that needs to be forwarded, the routing table is looked up before proceeding to the next hop. Based on the next hop forwarding address, the on-board address mapping table is consulted to obtain all available site addresses for the next hop address (addruj). and the current link quality estimate corresponding to all available site addresses. Select the transceiver with the highest link quality assessment value.

[0069] Step 4, Link Switching:

[0070] In business communication, the sending end uses cumulative sum control chart technology based on link status to decide on communication link switching, so as to ensure that business data is always transmitted with the optimal link.

[0071] Communication link switching includes link switching for uplink data transmission from user terminals and link switching for downlink data transmission from satellites.

[0072] In step four, specifically, the method for link switching of uplink data transmission by the user terminal is as follows: User terminal u j To satellites i During data transmission, the status of the currently used link is monitored in real time. When the packet error rate increases and exceeds the normal level, the communication service is switched to the communication transceiver with the highest estimated link quality value, excluding the currently used transceiver.

[0073] In step four, the further method for link switching of uplink data transmission by the user terminal is as follows: at the end of each packet error rate statistical estimation period t, the user terminal u j Calculate the current relationship with satellite s i Uplink transceiver used for communication Corresponding control chart cumulative sum in, For communication transceivers The allowed deviation of the uplink packet error rate jitter under normal circumstances; if is greater than the set decision threshold H n , it is determined that the link packet error rate exceeds the threshold, the value of 0 is set, the communication service is switched to the communication transceiver with the largest link quality estimation value except the currently used communication transceiver, otherwise the communication service continues to use the current communication transceiver.

[0074] In step four, the specific method for switching the satellite downlink data transmission link is as follows: the satellite s i monitors the state of the currently used link in real time, calculates the control chart cumulative sum of the downlink used by the current communication determines whether to switch the downlink according to whether the predetermined decision threshold is exceeded, and when switching is needed, the communication service is switched to the communication transceiver with the largest link quality estimation value except the currently used communication transceiver.

[0075] Step five, satellite protocol conversion:

[0076] The satellite performs protocol conversion of various communication link frames to unified network layer data packets through address mapping, and realizes the hinged communication of multiple heterogeneous links through the routing of IPv4 unified service data packets.

[0077] The protocol conversion process includes a framing process and a deframing process, and the deframing process is opposite to the framing process.

[0078] In step five, the framing process is as follows: for the uplink signal received by the satellite payload, the communication transceiver demodulates and processes the link frame to obtain the frame type through the frame header, for the IPv4 message in the frame payload, the IPv4 message in the frame payload is directly extracted; for other types of data formats in the frame payload, the corresponding IPv4 information is obtained through the station address information in the link frame header and combined with the address mapping table on the satellite to construct the IPv4 message header, and the frame payload and the IPv4 header are packaged to form the IPv4 message; the IPv4 message is routed and link selection is performed, and then the framing is performed to give the communication transceiver for modulation and transmission.

[0079] Application example:

[0080] The application example gives a kind of transmission method based on the above-mentioned embodiment of space-based heterogeneous multi-link networking, the working scene of the method of the application example is as shown in Figure 2 , including: satellite, user terminal, ground network management.

[0081] ​The satellite is a high-orbit satellite, responsible for receiving the uplink signal of the user terminal, processing and sending to the target user, wherein the processing process includes wireless signal receiving and demodulation, protocol frame resolution, routing and link selection, protocol frame encapsulation, modulation and transmission, and at the same time, the satellite network parameter configuration is carried out according to the ground network management instruction.

[0082] The user terminal is responsible for sending the network layer service data of the user to the satellite using a suitable transceiver, receiving the downlink signal sent by the satellite to itself, and sending the analyzed network layer data to the user.

[0083] The ground network management is the ground management center of the whole network, responsible for satellite network function configuration and whole network state maintenance.

[0084] Specifically:

[0085] First, the satellite s1 includes two types of communication transceivers, link estimation and routing modules, protocol conversion modules, and satellite network management agents:

[0086] The two types of communication transceivers are S low-speed communication transceivers and Ka high-speed communication transceivers used for modulating baseband data and demodulating intermediate frequency signals; S low-speed communication system protocol and Ka high-speed communication system protocol are run respectively, wherein the S link frame contains payload data and does not support IPv4 protocol, and the Ka frame contains network layer IPv4 protocol with IPv4 packet header; the design rate of the satellite to user and user to satellite wireless link in the above two communication systems is

[0087] The above is The bit error rate is The frame length is l1=500 bytes and l2=1000 bytes respectively. Then the uplink and downlink communication theoretical error packet rate of S and Ka transceivers is The user terminal u1 is also configured with S and Ka communication transceivers.

[0088] The link estimation and routing module is responsible for collecting and counting the downlink error packet rate of the S communication transceiver and the Ka high-speed communication transceiver to each terminal accessing the satellite in a timely manner, for calculating the downlink channel quality of the satellite to each terminal communication transceiver, and recording it in the routing table item corresponding to the terminal; when routing data packets, if there are multiple matching links to the target node, the path with good link quality is selected for transmission; at the same time, after the communication quality of the current transmission link deteriorates, other optimal communication path is switched in time.

[0089] Protocol conversion module, responsible for receiving link frames from S and Ka communication transceiver, according to the corresponding S low-speed communication system protocol or Ka high-speed communication system protocol to obtain frame payload data, and mark the communication transceiver number as needed to send to routing decision module; The IPv4 packet sent by the routing decision module is marked according to the routing decision result, and the corresponding S or Ka transceiver system is selected, and the payload in the IP data packet is framed according to the S low-speed communication system protocol or Ka high-speed communication system protocol. The payload is framed into S link frame or Ka link frame format, and then sent to the corresponding transceiver for modulation and transmission.

[0090] Satellite network management agent: responsible for receiving instruction information from ground network management, including address mapping information, link selection control signal, routing table item operation information, protocol conversion management, etc.

[0091] Second, the user terminal includes two types of communication transceivers and routing decision module:

[0092] User terminal 1 is configured with S low-speed communication transceiver and Ka high-speed communication transceiver to access satellite s1; The user terminal is connected with user equipment through network port for network data communication.

[0093] When the user needs to communicate through the satellite, the routing decision module is responsible for regularly estimating the uplink packet error rate of S / Ka transceiver, and selecting the communication transceiver with the best link quality for transmission.

[0094] Third, the ground network management: the ground network management is the management center of the satellite network, responsible for the network registration, authentication, address allocation, mobile management of the transceiver, the management of the global address mapping information of the satellite system, the configuration of the network parameters, etc. It interacts with the satellite through the feeder link.

[0095] Specifically, the method of the application example is performed according to the following steps:

[0096] Step 1, user terminal network access:

[0097] The user terminal accesses the satellite network through multiple types of heterogeneous communication transceivers, and saves the mapping information of the communication transceiver station address and IP address used by the user terminal on the satellite.

[0098] In this embodiment, the process of accessing the satellite network is: through the configured S or Ka communication transceiver, the satellite s1 sends the network access application to the ground network management center with its own station address and other identity authentication information, the satellite forwards the application data packet to the ground network management center, and the ground network management center performs authentication, and allocates an available IPv4 address addr u1The u1 is given, and a network entry success reply message containing the address is returned to the network entry terminal, informing it of the network entry success; the satellite forwards the network entry reply, and records the site address of the user terminal and the corresponding initialized link quality estimation and the IPv4 address addr allocated by the ground network management center u1 The mapping relationship is added into the on-board address mapping table.

[0099] Step two, link quality estimation

[0100] The user terminal and the satellite periodically count the data volume of the communication transceiver, and estimate the communication quality of each transmission link in combination with the link load and the packet loss rate.

[0101] The estimation of the communication quality of each transmission link includes the uplink service communication link quality estimation of the user terminal and the downlink quality estimation of the satellite service transmission.

[0102] In the present application example, the uplink service communication link quality estimation method of the user terminal is as follows: the S and Ka communication transceiver and The uplink communication quality estimation value at the current time t is

[0103] Wherein and are the uplink data volume statistics value and the uplink packet loss rate estimation value of the S and Ka communication transceiver and of the user u1 obtained at the time t in the current statistics period.

[0104] The statistics method of and the estimation method are as follows: the satellite s1 link estimation and routing module records the number of data packets transmitted by the S and Ka communication transceiver and the number of data packets received in each period. The user u1 link decision module records the number of data packets transmitted by the S and Ka communication transceiver and the number of data packets received in each period t. At the end of each statistics period t, the satellite s1 sends to the user u1, and the user u1 sends to the satellite s1. The user u1 estimates the uplink packet loss rate of the S and Ka transceiver When a communication transceiver has no uplink data communication, the corresponding

[0105] In this application example, the method for estimating the quality of the downlink of the satellite service transmission is as follows:

[0106] In this application example, the communication between the satellite and the user terminal u1 is taken as an example, and the method for other users is consistent. The satellite s i The method for estimating the quality of the downlink is the same as the method for estimating the quality of the uplink of the user, and the satellite s1 estimates the downlink packet loss rate of the Ka transceiver When there is no data communication in the S or Ka communication transceiver or is 0, at this time Then the quality of the downlink of the satellite is calculated

[0107] And it is recorded in real time to the corresponding user communication transceiver site address In the table entry in the address mapping table on the satellite

[0108]

[0109] Step three, link selection:

[0110] In the service communication, the sending end selects the optimal link for communication according to the link quality estimation obtained in step two.

[0111] The link selection includes the selection of the uplink service communication link of the user terminal and the selection of the downlink of the satellite service transmission.

[0112] In this application example, the method for selecting the uplink service communication link of the user terminal is as follows: when the user terminal starts to send data through the satellite, the routing decision module selects the communication transceiver with the best current communication quality, i.e., the largest link quality estimation value, to send data information to the satellite according to the currently estimated communication transceiver link quality.

[0113] In this application example, the method for selecting the downlink of the satellite service transmission is as follows: for each IPv4 data packet that needs to be sent down, the next hop is forwarded after searching the routing table, the address mapping table on the satellite is searched according to the next hop forwarding address, and all available site addresses of the next hop and the current link quality of the next hop are obtained.

[0114] The transceiver with the largest link quality evaluation value is selected.

[0115] In the service communication, the sending end decides the communication link switching by using the cumulative sum and control chart technology according to the link state, so as to ensure that the service data is always transmitted through the optimal link.

[0116] The communication link switching includes link switching of user terminal uplink data transmission and link switching of satellite downlink data transmission.

[0117] In the application example, the method of link switching of user terminal uplink data transmission is as follows: during the data transmission of user u1 through the satellite, the routing decision module monitors the state of the current used link in real time, and when the packet error rate increases and exceeds the normal level, switches to other communication transceivers with the largest link quality estimation value for transmission.

[0118] The specific decision process is as follows: at the end of each packet error rate statistical estimation period, user u1 calculates the uplink communication transceiver currently used for communication with the satellite The corresponding control chart cumulative sum Wherein is the standard deviation of the theoretical packet error rate of the nth type of communication transceiver in the normal environment. If is greater than the set decision threshold , it is determined that the link packet error rate exceeds the threshold, and is set to 0, and the communication service is switched to other available communication transceivers with the largest link quality estimation value.

[0119] In the application example, the method of link switching of satellite downlink data transmission is as follows: the routing and routing module monitors the state of the current used link in real time, and calculates the control chart cumulative sum of the downlink corresponding to the current communication using a similar method to the link switching of the terminal Wherein is the standard deviation of the theoretical packet error rate of the nth type of communication transceiver in the normal environment. If is greater than the set decision threshold , it is determined that the link packet error rate exceeds the threshold, and is set to 0, and the communication service is switched to other available communication transceivers with the largest link quality estimation value.

[0120] Step five, satellite protocol conversion:

[0121] The satellite performs protocol conversion of various communication link frames to unified network layer data packets through address mapping, and realizes the hinged communication of multiple heterogeneous links through the routing of IPv4 unified bearer service data packets.

[0122] The protocol conversion process includes the framing process and the deframing process, and the deframing process is opposite to the framing process.

[0123] In the application example, the frame-unpacking process is: the network layer and link layer data of S and Ka different system protocols are uniformly converted, so that multiple systems can be routed and exchanged under the unified IP bearing. Here, the S link frame contains payload data, does not support IPv4 protocol, and the Ka frame contains network layer IPv4 protocol with IPv4 packet header. The specific protocol conversion process is: for the S or Ka uplink signal received by the satellite payload, the S or Ka communication transceiver delivers the demodulated link frame to the protocol conversion module, the protocol conversion module identifies the frame type through the frame header, for S data frame, the source and destination node corresponding IPv4 addresses are obtained through the source and destination site address information in the link frame header combined with the on-board address mapping table, the IPv4 packet header is constructed, the S frame payload and IPv4 header are packaged to form an IPv4 packet; for Ka data frame, the IPv4 packet in the frame payload is directly extracted. Then the IPv4 packet is handed over to the link awareness and routing module for routing and link selection, and then the frame is sealed and handed over to the communication transceiver for modulation and transmission.

Claims

1. A method for selective transmission in space-based heterogeneous multi-link networking, characterized in that, The method is performed according to the following steps: Step one, user terminal network access: The user terminal accesses the satellite network through a multi-type heterogeneous communication transceiver, and the mapping information of the communication transceiver station address and IP address used by the user terminal is saved on the satellite; The expression for the aforementioned communication transceiver is: Tr={ |1≤n≤N}; In the formula: Tr represents a set of transceivers; N represents the type of transceiver; n represents the type number of transceiver; In the communication system used by the nth class of communication transceivers, the satellite-to-user terminal radio link is designed for a rate of , and the user terminal-to-satellite radio link is designed for a rate of ; the satellite-to-user terminal radio link is designed for an error rate of , and the user terminal-to-satellite radio link is designed for an error rate of ; and the frame length is defined as l n ; The theoretical error packet rate of the uplink communication of the nth type of communication transceiver is The theoretical error packet rate of the downlink communication of the nth type of communication transceiver is ; Then the satellite s i The load is configured to ={ } Tr, access satellite The user terminal The communication transceiver is configured to ; Step two, link quality estimation: The user terminal and the satellite periodically count the data volume of the communication transceiver, and estimate the communication quality of each transmission link in combination with the link load and packet loss rate; The estimation of the communication quality of each transmission link includes user terminal uplink service communication link quality estimation and satellite service transmission downlink quality estimation; Step three, link selection: In the service communication, the sending end selects the optimal link for communication according to the link quality estimation obtained in step two; The link selection includes user terminal uplink service communication link selection and satellite service transmission downlink selection; Step four, link switching: In the service communication, the sending end decides the communication link switching through the link state using the cumulative sum and control chart technique to ensure that the service data is always transmitted through the optimal link; The communication link switching includes user terminal uplink data transmission link switching and satellite downlink data transmission link switching; The method for link switching of uplink data transmission of the user terminal is: at the end of each packet error rate statistical estimation period, the user terminal u j calculating the current packet error rate of the user terminal u i uplink communication transceiver used for communication corresponding control chart cumulative sum wherein, communication transceiver normal uplink packet error rate jitter allowance, , standard deviation of the theoretical uplink packet error rate of the nth communication transceiver in normal environment; user terminal u j communication transceiver in the current statistical period obtained at time t uplink transmission packet error rate estimation value; uplink communication theoretical packet error rate of the nth communication transceiver If greater than a set decision threshold H n , then it is determined that the link packet error rate exceeds the threshold, the flag is set to 0, and the communication service is switched to the communication transceiver with the largest link quality estimate value except the currently used communication transceiver, otherwise the current communication transceiver is continued to be used for service communication. ​ The method for switching the link of the satellite downlink data transmission is: the satellite s i Real-time monitoring of the current link state, calculating the control chart cumulative sum of the current communication using downlink , wherein is the communication transceiver The normal downlink packet error rate jitter allowance, , is the standard deviation of the theoretical downlink packet error rate of the nth type of communication transceiver in the normal environment; is the satellite s i The downlink transmission packet error rate estimate value of each transceiver to the user terminal u j ; The downlink communication theoretical packet error rate of the nth type of communication transceiver; The determination of whether to switch the downlink is determined by whether the predetermined determination threshold is exceeded, and when switching is required, the communication service is switched to the communication transceiver with the maximum link quality estimation value other than the currently used communication transceiver; Step five, satellite protocol conversion: The satellite performs protocol conversion of various communication link frames to unified network layer data packets through address mapping to realize the hinged communication of multiple heterogeneous links by routing the IPv4 unified service data packets; The protocol conversion process includes a framing process and an unframing process, and the unframing process is opposite to the framing process. 2.The space-based heterogeneous multi-link networking selective transmission method according to claim 1, wherein, In step one, the process of accessing the satellite network is as follows: the user terminal selects the available communication transceiver through the accessed satellite sends the network management center on the ground the network access application with the site address of the available communication transceiver ={ } and the identity authentication information other than the identity authentication information. The satellite forwards the request to the ground network management center, which assigns an available IPv4 address to the user terminal and sends it back to the user terminal in a reply to the request, indicating that the request was successful . When the satellite relays the network access reply, it records the user terminal's current IPv4 address. With site address { Mapping relationship of} <addr uj , >; Wherein: representing a user terminal configured communication transceiver of the station address; represents the initial value of downlink quality, i.e. the downlink error packet rate when the link is normal. 3.The space-based heterogeneous multi-link networking selective transmission method according to claim 1, wherein, In step two, the method for estimating the user terminal uplink service communication link quality is: In the formula: communication transceiver maximum link quality estimate of the uplink communication quality at time t; for a communication transceiver a designed value of an uplink communication rate; T is the statistical period; for the user terminal u j the communication transceiver in the current statistical period obtained at time t uplink data packet statistical value; the user terminal u j the communication transceiver in the current statistical period obtained at time t the uplink transmission packet error rate estimate value. 4.The space-based heterogeneous multi-link networking selective transmission method of claim 3, wherein, In step two, the aforementioned The statistical methods and the aforementioned The estimation method is as follows: satellite s i Record the communication between each transceiver and the user terminal u within each period t. j Sending and receiving from user terminal u j Number of data packets received { }and{ User terminal u j Record the communication transceiver's communication signal to satellite s within each period t. i Sending and receiving from satellites i Number of data packets received { }and{ };Satellite s i and user terminal u j At the end of each statistical period t, the received statistical values ​​collected by itself will be { }and{ Each data packet is sent to the other end of the communication to inform it of the number of data packets received; user terminal u j Estimate the uplink data packet transmission success rate for each transceiver. ; When there is no uplink data communication = 0, at which time . 5.The space-based heterogeneous multi-link networking selective transmission method according to claim 3, wherein, In step three, the method for selecting the uplink communication link for the user terminal is as follows: User terminal u j via satellite i To the user terminal u j When an external user terminal sends data, it selects the transceiver with the best current communication quality based on the current statistical estimate of the transceiver link quality, i.e., the one with the highest estimated link quality. The communication transceiver transmits signals to the satellite. i Send data. 6.The space-based heterogeneous multi-link networking selective transmission method according to claim 5, wherein, In step two, the method for estimating the satellite service transmission downlink quality is: Satellite s i Downlink packet error rate estimate for each transceiver to user terminal u j When there is no downlink data communication = 0, at this time record ; Calculate the satellite downlink quality estimate , and modify the satellite downlink quality estimate corresponding to the user terminal communication transceiver site address Link quality estimate in the on-board address mapping table <addr uj ,( , )>;​ In step three, the method for selecting a satellite service transmission downlink is as follows: for each IPv4 data packet needing to be forwarded, a routing table is searched and then a next hop is forwarded, a satellite address mapping table is searched according to the next hop forwarding address, and an available all-site address of the next hop addruj is obtained , and a current link quality estimation value corresponding to the available all-site address , and a transceiver with the largest link quality estimation value is selected. 7.The space-based heterogeneous multi-link networking selective transmission method according to claim 1, wherein, In step five, the framing process is: for the uplink signal received by the satellite payload, the communication transceiver demodulates and processes to obtain a link frame, identifies the frame type through the frame header, and for the IPv4 message in the frame payload, directly extracts the IPv4 message in the frame payload; for other types of data format in the frame payload, the corresponding IPv4 information is obtained through the station address information in the link frame header in combination with the address mapping table on the satellite to construct an IPv4 message header, and the frame payload and the IPv4 header are packaged to form an IPv4 message; The IPv4 message is routed and link selected, and then framed to be modulated and transmitted by the communication transceiver.

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