CN111866878A - A terminal login method in a satellite communication system - Google Patents

Abstract

The invention provides a terminal login method in a satellite communication system, including: a terminal receives a broadcast message of a high-orbit satellite and sends a log-in request to the high-orbit satellite; the high-orbit satellite receives a log-in request and sends a log-in request response to the terminal, and the terminal receives In response to the login request, in this process, a low-orbit satellite serving the terminal is specified based on the login request or based on the login request response; the terminal establishes a connection with the specified low-orbit satellite. The terminal login method in the satellite communication system of the present invention realizes efficient terminal login and overcomes the high mobility of low-orbit satellites by initiating the login process from the terminal to the high-orbit satellite, and the high-orbit satellite assists the terminal to connect to the low-orbit satellite. The impact on the initial access of the terminal improves the success rate of establishing a connection between the terminal and the low-orbit satellite.

Description

A terminal login method in a satellite communication system

technical field

The invention belongs to the technical field of wireless communication, and in particular relates to a terminal login method in a satellite communication system.

Background technique

With the continuous development of satellite and communication technology, the use of satellites in multi-layer orbits to jointly build a satellite communication system has become an important means to achieve global mobile network coverage. Satellites in different orbits have different motion states, coverage and transmission characteristics. The high-orbit satellite is located in a geosynchronous orbit of 35,786km, which is relatively stationary with the ground and has a large coverage area, but its transmission rate is limited due to the long transmission path. The orbital altitude of low-orbit satellites is usually around 300-1500km. Using beamforming and other technologies can achieve higher transmission rates. However, due to their higher moving speed relative to the ground, the Doppler frequency shift is large, The transmission timing changes rapidly and the available service time is short, which brings certain challenges to the synchronization, access and mobility management of the terminal.

When a satellite terminal logs in to a satellite communication system, it first needs to receive broadcast messages sent by the satellite in order to achieve downlink synchronization and obtain necessary information needed to access the system. Then the terminal sends a login request to the selected serving satellite, and receives the corresponding login request response, so as to realize the login authentication of the terminal and obtain the required resource configuration. However, when the terminal initiates the above login process to the low-orbit satellite, the high-frequency offset, high time offset, and difficult antenna alignment caused by the high mobility of the low-orbit satellite may make it difficult for the terminal's login request to be accurately received. This hinders the subsequent data transmission process.

Therefore, there is a need for a terminal login method in a satellite communication system to improve the success rate of establishing a connection between a terminal and a low-orbit satellite.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a terminal registration method in a satellite communication system, so as to realize efficient terminal registration and improve the success rate of establishing a connection between the terminal and the low-orbit satellite.

In order to achieve the above purpose, the present invention provides a terminal registration method in a satellite communication system. The applicable satellite communication system is a joint high- and low-orbit satellite network, which includes terminals, high-orbit satellites and low-orbit satellites. Methods include:

Step S1: the terminal receives the broadcast message of the high-orbit satellite and sends a login request to the high-orbit satellite;

Step S2: the high-orbit satellite receives the log-in request and sends the log-in request response to the terminal, and the terminal receives the log-in request response. In this process, the low-orbit satellite that provides services for the terminal is designated based on the log-in request or based on the log-in request response;

Step S3: The terminal establishes a connection with the designated low-orbit satellite.

In the step S1, the broadcast message of the high-orbit satellite includes a network clock reference, a network information table, a satellite location table and a log-in slot location;

The terminal sends a log-in request to the high-orbit satellite at the log-in slot position, where the log-in request includes terminal ID and terminal capability information.

The terminal has a positioning function, then in the step S1, the login request further includes the terminal position information; in the step S2, the satellite communication system is based on the terminal position information or both based on the terminal position information and the terminal position information. The terminal capability information is used to designate a low-orbit satellite serving the terminal, and the login request response includes the information of the designated low-orbit satellite.

The terminal does not have a positioning function, then in the step S1, the login request does not include the terminal location information; in the step S2, the login request response includes the candidate low-orbit satellites that can provide services for the terminal. information, based on the information of the candidate low-orbit satellites in the response to the login request, the terminal specifies the low-orbit satellites that serve the terminal in the following ways:

Step S21: the terminal measures the candidate low-orbit satellites based on the information of the candidate low-orbit satellites in the login request response, and sends a measurement report to the high-orbit satellites;

Step S22: The satellite communication system designates a low-orbit satellite serving the terminal based on the measurement report, and the high-orbit satellite sends a low-orbit satellite connection command to the terminal, where the low-orbit satellite connection command includes the information of the designated low-orbit satellite.

In the step S2, the information of the candidate low-orbit satellites includes:

IDs of multiple candidate low-orbit satellites, frequencies and reference signals used by the candidate low-orbit satellites; and beam IDs of multiple candidate low-orbit satellites, frequencies and reference signals used by the candidate beams; at least one of and a transmission resource and transmission configuration for sending the measurement report.

In the step S21, measuring the candidate low-orbit satellites includes: receiving a corresponding reference signal at the frequency of each candidate low-orbit satellite and/or beam to measure the corresponding low-orbit satellite and/or beam. the strength of the reference signal;

In the step S22, the measurement report includes one or more preferred low-orbit satellite IDs and their measurement information; and/or one or more preferred beam IDs and their measurement information.

In the step S2, the information of the designated low-orbit satellite includes: the ID of the designated low-orbit satellite and/or the beam ID of the designated low-orbit satellite, the position of the control time slot allocated for the terminal, and the timing and frequency Offset.

In the step S3, the terminal establishes a connection with the designated low-orbit satellite in the following manner:

Step S31: the terminal receives the broadcast message sent by the designated low-orbit satellite;

Step S32: the terminal uses the timing and frequency offset in the information of the designated low-orbit satellite to send a control message to the low-orbit satellite at the allocated control time slot position;

Step S33: The low-orbit satellite feeds back a response message to the terminal.

In the step S31, the broadcast message sent by the low-orbit satellite includes a network clock reference and a satellite position table;

In the step S32, the control message includes the terminal ID, channel state information and power headroom;

In the step S33, the response message includes a connection success indication, a transmission resource, a transmission configuration and a correction message.

The terminal login method in the satellite communication system of the present invention initiates a login process to the high-orbit satellite through the terminal, and the high-orbit satellite assists the terminal to connect to the low-orbit satellite. Compared with high-speed moving low-orbit satellites, it is less difficult for the terminal to synchronize with the high-orbit satellite at the initial login and complete the login process, thus realizing efficient terminal login. In addition, since the high-orbit satellite can provide the terminal with low-orbit satellite information, timing and frequency offset after completing the terminal certification, and allocate dedicated transmission resources, the terminal can better compensate for these information and resources after obtaining the information and resources. The high-frequency offset and time offset caused by the high mobility of low-orbit satellites, and avoid conflicts caused by competing access, significantly improve the success rate of establishing connections with low-orbit satellites.

Description of drawings

FIG. 1 is a flow chart of a terminal registration method in the satellite communication system of the present invention.

FIG. 2 is a scene diagram of a satellite communication system to which the terminal registration method in the satellite communication system of the present invention is applied.

FIG. 3 is a signaling flow chart of a terminal login method in a satellite communication system according to the first embodiment of the present invention.

FIG. 4 is a signaling flow chart of a terminal login method in a satellite communication system according to a second embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following implementation. example.

Figure 2 shows a scene of a satellite communication system to which the terminal login method in the satellite communication system of the present invention is applicable. The applicable satellite communication system is a joint high- and low-orbit satellite network, and the satellite communication system at least includes a terminal 1, a high-orbit orbit Satellite 2 and LEO Satellite 3. Data and control signaling are transmitted between the terminal 1 and the high-orbit satellite 2 and between the terminal 1 and the low-orbit satellite 3 through the user link 5 . In addition, satellite communication systems typically include gateway stations 4 on the ground. The ground gateway 4 has a data gateway function, and is responsible for part or all of the control and management functions of the satellite communication system, which is used to provide a feeder link 6 to the satellite and transmit data and control signaling, but the technical solution of this patent does not. It involves the transmission on the feeder link, mainly for the signaling transmission on the user link between the terminal 1 and the satellites 2 and 3. The low-orbit satellite 3 moves at high speed relative to the ground, and can be connected to the gateway 4 through the feeder link 6 , or connected to the high-orbit satellite 2 through the inter-satellite link 7 . The high-orbit satellite 2 remains relatively stationary with the ground, and is connected to the gateway 4 through a feeder link.

The first embodiment: a terminal login method in a satellite communication system in which the terminal has a positioning function

In this embodiment, in the satellite communication system, the terminal has a positioning function.

As shown in Figure 1 and Figure 3, the terminal login method in the satellite communication system specifically includes the following steps:

Step S1 : the terminal 1 receives the broadcast message of the high-orbit satellite 2 , and sends a login request to the high-orbit satellite 2 .

The broadcast message received by the terminal 1 includes, but is not limited to, a network clock reference, a network information table, a satellite location table, and a log-in slot location, and the like. These broadcast messages are broadcast messages of the existing satellite communication system. The network clock reference is mainly used for the clock synchronization of the terminal 1 during initial access, the network information table is used to obtain satellite communication network information, and the satellite position table is used for antenna alignment. .

The terminal 1 sends a registration request to the high-orbit satellite 2 at the registration time slot position. The login request includes but is not limited to terminal ID and terminal capability information. In addition, in this embodiment, if the terminal has a positioning function, the login request also includes terminal location information.

Step S2: the high-orbit satellite 2 receives the log-in request and sends a log-in request response to the terminal 1, and the terminal 1 receives the log-in request response. low-orbit satellites in service;

In this embodiment, since the terminal 1 has a positioning function, the log-in request sent by the terminal 1 includes the terminal position information. Therefore, the satellite communication system is based on the terminal position information in the log-in request or both based on the terminal position information in the log-in request and The terminal capability information is used to designate the low-orbit satellite that serves the terminal, and the login request response includes the information of the designated low-orbit satellite 3 that serves the terminal 1 .

Among them, the decision to designate the low-orbit satellite to provide service for the terminal can be made by the satellite communication system, and specifically can be made by the control function in the ground gateway station or the control function in the high-orbit satellite. The decision-making process can use existing techniques, such as selecting the LEO satellite with the closest distance and the best channel quality based on terminal location or measurement reports.

The information of the designated low-orbit satellite 3 includes, but is not limited to: the ID of the designated low-orbit satellite 3 and/or the beam ID of the designated low-orbit satellite 3, the assigned control slot position for the terminal 1, and the timing and frequency offset amount, etc.

Among them, a low-orbit satellite may generate multiple beams using technologies such as beamforming, and the coverage, frequency band, and bandwidth of each beam may be different. Low-orbit satellites configured with multiple beams need to serve terminals through the beams they generate. The ID of the low-orbit satellite 3 and the beam ID of the low-orbit satellite 3 are used to inform the terminal of the beam in the low-orbit satellite to be connected in step 3, the ID of the designated low-orbit satellite 3 and/or the designated low-orbit satellite 3 The beam ID indicates that at least the satellite ID needs to be determined, and the beam ID can be determined after the terminal is connected to the low-orbit satellite. The control slot position is the resource allocated by the low-orbit satellite 3 to the terminal 1 to send the control message, and is related to the terminal capability information, and the timing and frequency offset are calculated according to the terminal position information.

Step S3: The terminal 1 establishes a connection with the designated low-orbit satellite 3.

For a terminal with positioning function, the terminal can establish a connection with the designated low-orbit satellite 3 in the following manner based on the information of the designated low-orbit satellite 3 in the login request response:

Step S31: The terminal 1 receives a broadcast message sent by the designated low-orbit satellite 3; the broadcast message sent by the low-orbit satellite 3 includes a network clock reference, a satellite position table, and the like. The low-orbit satellite 3 periodically broadcasts these broadcast messages, and the terminal 1 receives the corresponding broadcast message by searching the frequency band to find the ID of the specified low-orbit satellite 3 and/or the beam ID of the low-orbit satellite 3 .

Step S32: The terminal 1 uses the timing and frequency offset in the information of the designated low-orbit satellite 3 to send a control message to the low-orbit satellite 3 at the assigned control time slot position; the control message includes the terminal ID, channel state information and power headroom, etc. These control messages are used to determine the modulation and coding, transmit power and other configurations of subsequent data transmissions.

Step S33: The low-orbit satellite 3 feeds back a response message to the terminal 1; the response message includes a connection success indication, transmission resources, transmission configuration, and correction messages. The response messages are all configurations used for subsequent data transmission, the transmission resources are the time-frequency resources configured for data transmission, the transmission configuration includes modulation and coding, transmit power and other configurations, and the correction message includes timing, frequency, and power corrections.

Thus, after the above connection process is completed, that is, after step S3 is completed, the terminal 1 can start data transmission with the low-orbit satellite 3 .

Second embodiment: terminal login method in a satellite communication system where the terminal does not have a positioning function

As shown in Figure 1 and Figure 4, the terminal login method in the satellite communication system specifically includes the following steps:

Step S1: The terminal 1 receives the broadcast message of the high-orbit satellite and sends a login request to the high-orbit satellite.

The broadcast message received by the terminal 1 includes a network clock reference, a network information table, a satellite location table, a log-in slot location, and the like.

The terminal sends a log-in request to the high-orbit satellite at the log-in time slot position, where the log-in request includes but is not limited to terminal ID and terminal capability information. In this embodiment, since the terminal does not have a positioning function, the login request does not include terminal location information.

Step S2: the high-orbit satellite 2 receives the login request and sends a login request response to the terminal 1, and the terminal 1 receives the login request response.

Since in step S1, the login request does not include the terminal location information, the satellite communication system cannot directly designate the low-orbit satellite 3 that provides services for the terminal. Therefore, in step S2, the login request response includes information that can serve the terminal. Based on the information of the candidate low-orbit satellites 3 that provide services, the terminal 1 specifies the low-orbit satellites 3 that provide services to the terminal 1 based on the information of the candidate low-orbit satellites 3 in the registration request response.

Wherein, the information of the candidate low-orbit satellite 3 includes but is not limited to:

IDs of multiple candidate low-orbit satellites, frequencies and reference signals used by the candidate low-orbit satellites; and beam IDs of multiple candidate low-orbit satellites, frequencies and reference signals used by the candidate beams; at least one of species; and transmission resources and transmission configurations for sending measurement reports.

Specifically, if the satellite does not use beamforming technology (ie, there are no multiple beams), or uses a dedicated frequency band to cover the entire service area (which can be understood as a wide beam with a large coverage area for broadcasting information, etc.) , then the satellite needs to send a satellite-level reference signal on the used frequency for the terminal to measure the signal strength of different satellites.

If the satellite is configured with multiple beams (different frequency points may be used), a beam-level reference signal needs to be sent on each beam for the terminal to measure the signal strength of different beams.

The frequency refers to the frequency used by the satellite or beam, and the reference signal is a known signal such as a pilot signal sent on the satellite or beam, which is used by the terminal to measure the signal strength. The terminal needs to receive the reference signal on the frequency point of the satellite to measure the signal strength.

Based on the information of the candidate low-orbit satellites in the log-in request response, Terminal 1 specifically adopts the following method to designate the low-orbit satellites that provide services for Terminal 1:

Step S21 : The terminal 1 measures the candidate low-orbit satellite 3 based on the information of the candidate low-orbit satellite 3 in the registration request response, and sends a measurement report to the high-orbit satellite 2 .

Since the information of the candidate low-orbit satellite 3 includes the frequency and reference signal used by the candidate low-orbit satellite or the frequency and reference signal used by the candidate beam, the measurement of the candidate low-orbit satellite 3 includes: Corresponding reference signals are received at the frequencies of the orbiting satellites and/or beams to measure the strength of the reference signals of the corresponding low-orbiting satellites and/or beams.

Correspondingly, the measurement report includes the IDs of one or more preferred low-orbit satellites 3 and their measurement information; and/or one or more preferred beam IDs and their measurement information. That is, at least the ID of the low-orbit satellite 3 needs to be decided; the beam ID of the low-orbit satellite 3 can be specified at the same time, or the decision can be made after the terminal 1 is connected to the low-orbit satellite 3 . If the beam ID of the low-orbit satellite 3 needs to be specified at the same time, at least the beam ID and measurement information are required, and the optimal beam is selected according to the beam measurement information, and then the satellite that generates the beam is selected.

Step S22 : the satellite communication system designates the low-orbit satellite serving the terminal based on the measurement report, and the high-orbit satellite sends a low-orbit satellite connection command to the terminal 1 , the low-orbit satellite connection command includes the information of the designated low-orbit satellite 3 .

The decision to designate the low-orbit satellite to serve the terminal can be made by the satellite communication system, specifically by the control function in the ground gateway or the control function in the high-orbit satellite. The decision-making process can use existing techniques, such as selecting the beam of the LEO satellite with the best channel quality according to the measurement report.

The information of the designated low-orbit satellite 3 includes, but is not limited to: the ID of the designated low-orbit satellite 3 and/or the beam ID of the designated low-orbit satellite 3, the assigned control slot position for the terminal 1, and the timing and frequency offset amount, etc.

Step S3: The terminal 1 establishes a connection with the designated low-orbit satellite 3.

In this embodiment, for the terminal 1 without the positioning function, the terminal 1 can establish a connection with the designated low-orbit satellite 3 in the following manner based on the information of the designated low-orbit satellite 3 in the low-orbit satellite connection command:

Step S31: The terminal 1 receives a broadcast message sent by the designated low-orbit satellite 3; the broadcast message sent by the low-orbit satellite 3 includes a network clock reference, a satellite position table, and the like.

Step S32: The terminal 1 uses the timing and frequency offset in the information of the designated low-orbit satellite 3 to send a control message to the low-orbit satellite 3 at the assigned control time slot position; the control message includes the terminal ID, channel state information and power headroom, etc.

Step S33: The low-orbit satellite 3 feeds back a response message to the terminal 1; the response message includes a connection success indication, transmission resources, transmission configuration, and correction messages.

Thus, after completing the above connection process, the terminal can start data transmission with the low-orbit satellite.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can be made to the above-mentioned embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and descriptions of the present application shall fall within the protection scope of the claims of the present invention. What is not described in detail in the present invention is conventional technical content.

Claims (9)

1. A terminal login method in a satellite communication system is characterized in that the applicable satellite communication system is a high-low orbit satellite combined network, the satellite communication system comprises a terminal, a high orbit satellite and a low orbit satellite, and the terminal login method comprises the following steps:

Step S1: the terminal receives the broadcast message of the high orbit satellite and sends a login request to the high orbit satellite;

step S2: the high orbit satellite receives the login request and sends a login request response to the terminal, and the terminal receives the login request response and designates the low orbit satellite serving by the terminal based on the login request or the login request response in the process;

step S3: the terminal establishes a connection with the designated low earth orbit satellite.

2. The terminal registration method in a satellite communication system according to claim 1, wherein in the step S1, the broadcast message of the high-orbit satellite includes a network clock reference, a network information table, a satellite position table, and a registration slot position;

and the terminal sends a login request to the high orbit satellite at the login time slot position, wherein the login request comprises a terminal ID and terminal capability information.

3. The terminal registration method in a satellite communication system according to claim 2, wherein the terminal has a positioning function, the registration request further includes terminal location information in the step S1;

in the step S2, in the above step,

the satellite communication system specifies a low-orbit satellite that the terminal provides service based on the terminal position information or both the terminal position information and the terminal capability information, and the login request response includes information of the specified low-orbit satellite.

4. The terminal registration method in a satellite communication system according to claim 2, wherein the terminal has no positioning function, then in the step S1, the registration request does not include terminal position information;

in the step S2, in the above step,

the login request response comprises information of candidate low-orbit satellites capable of providing services for the terminal, and the terminal is specified as the low-orbit satellite providing the services for the terminal based on the information of the candidate low-orbit satellites in the login request response in the following ways:

step S21: the terminal measures the candidate low-orbit satellites based on the information of the candidate low-orbit satellites in the login request response and sends a measurement report to the high-orbit satellites;

step S22: the satellite communication system specifies a low-orbit satellite serving the terminal based on the measurement report, and the high-orbit satellite transmits a low-orbit satellite connection command to the terminal, the low-orbit satellite connection command containing information of the specified low-orbit satellite.

5. The terminal registration method in a satellite communication system according to claim 4,

in step S2, the information of the candidate low-earth orbit satellite includes:

the IDs of a plurality of candidate low-orbit satellites, the frequencies used by the candidate low-orbit satellites and the reference signals; and

A beam ID of a plurality of candidate low earth satellites, a frequency used by the candidate beam, and a reference signal; at least one of;

and a transmission resource and a transmission configuration for sending the measurement report.

6. The terminal registration method in a satellite communication system according to claim 5,

in step S21, the measurement of the candidate low-earth orbit satellite includes: receiving a corresponding reference signal at the frequency of each candidate low-earth satellite and/or beam to measure the strength of the reference signal of the corresponding low-earth satellite and/or beam;

in step S22, the measurement report includes one or more preferred low-earth orbit satellite IDs and measurement information thereof; and/or one or more preferred beam IDs and their measurement information.

7. The terminal registration method in a satellite communication system according to any one of claims 3 to 6, wherein in the step S2, the information of the specified low-earth satellite includes: an ID of the designated low earth orbit satellite and/or a beam ID of the designated low earth orbit satellite, a control slot location assigned for the terminal, and a timing and frequency offset.

8. The method for logging on a terminal in a satellite communication system according to claim 7, wherein in said step S3, the terminal establishes a connection with the specified low earth orbit satellite in the following way:

Step S31: a terminal receives a broadcast message sent by a designated low-orbit satellite;

step S32: the terminal sends a control message to the low-orbit satellite at the position of the allocated control time slot by using the timing and frequency offset in the information of the designated low-orbit satellite;

step S33: and the low-earth orbit satellite feeds back a response message to the terminal.

9. The terminal registration method in a satellite communication system according to claim 8, wherein in the step S31, the broadcast message transmitted by the low-earth satellite includes a network clock reference and a satellite position table;

in the step S32, the control message includes a terminal ID, channel state information, and a power headroom;

in the step S33, the response message includes a connection success indication, transmission resources, transmission configuration, and a correction message.

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