CN114301515B - Terminal simulator for low-earth-orbit satellite constellation communication system and control method - Google Patents
Terminal simulator for low-earth-orbit satellite constellation communication system and control method Download PDFInfo
- Publication number
- CN114301515B CN114301515B CN202111618908.5A CN202111618908A CN114301515B CN 114301515 B CN114301515 B CN 114301515B CN 202111618908 A CN202111618908 A CN 202111618908A CN 114301515 B CN114301515 B CN 114301515B
- Authority
- CN
- China
- Prior art keywords
- terminal
- multiple access
- module
- uplink
- satellite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Radio Relay Systems (AREA)
Abstract
The invention relates to a terminal simulator and a control method for a low-orbit satellite constellation communication system, wherein the multiple access mode of the terminal simulator for communicating with a satellite comprises one or a combination of a plurality of time division multiple access, a frequency division multiple access, a code division multiple access and a space division multiple access, the terminal simulator comprises a terminal uplink and receiving parameter simulation module, a local pps signal synchronization module, a spread spectrum transmitting module and a spread spectrum receiving module, the terminal uplink and receiving parameter simulation module is used for outputting a multiple access control signal which corresponds to the set multiple access mode and is used for uplink and receiving of the terminal, the spread spectrum receiving module is used for receiving and demodulating a downlink signal sent by the satellite, and the spread spectrum transmitting module is used for receiving the multiple access control signal and outputting the uplink signal to the satellite. By combining multiple access modes, the communication capacity and the test efficiency of the satellite constellation communication system can be improved from multiple angles of time, frequency, address and space.
Description
Technical Field
The invention relates to the technical field of satellite communication, in particular to a terminal simulator and a control method for a low-earth-orbit satellite constellation communication system.
Background
Satellites can be generally classified into three categories according to different operating heights: high orbit satellites, medium orbit satellites, and low orbit satellites. Because the distance between the satellite and the ground is close, the low-orbit satellite communication system has the advantages of small time delay, small path loss, small transmitting power and the like, and is widely applied to various fields. The low-orbit satellite constellation can provide global coverage, and rapidly improve the capabilities of satellite communication, satellite remote sensing and the like; the potential is huge in the aspect of communication broadband, and the service quality can be improved by lower signal propagation delay; the low-orbit constellation is applied to the signal enhancement of the current global navigation satellite system, and the rapid and accurate positioning can be realized. The satellite constellation arranges a plurality of satellites on a plurality of orbital planes, a cellular service cell is formed on the earth surface through a communication link, and a user terminal in the service cell is covered by at least one satellite and accesses the system at a specified time slot.
The terminal simulation is used as an important basis for the on-orbit running joint debugging test of the satellite, and plays an important guiding role in the ground terminal development process. The terminal simulator can receive and process downlink signals transmitted by the satellite and transmit uplink signals for Doppler compensation and satellite-to-ground distance compensation. The terminal simulator can receive and process the satellite high dynamic signal and carry out Doppler compensation and satellite-ground distance compensation on the satellite high dynamic signal; specific signals can also be generated to verify the acquisition and tracking performance of the satellite receiver.
In the prior art, a terminal simulator for a low earth orbit satellite communication system generally adopts a code division multiple access mode to realize communication with a satellite, the number of users is influenced by the number of pseudo-random codes, and meanwhile, the system has fewer accessible users and lower test efficiency of a simulated satellite constellation communication system.
Therefore, it is desirable to provide a terminal simulator that improves the communication capacity of a low-earth orbit satellite communication system and increases the number of terminals that can be simulated to solve the above-described technical problems.
Disclosure of Invention
In order to solve the technical problem, the invention provides a terminal simulator for a low earth orbit satellite constellation communication system. The problems that in the prior art, a code division multiple access mode is adopted to realize communication with different user terminals, the number of accessible users is too small, and the testing efficiency of a communication system is low are solved.
The technical effects of the invention are realized as follows:
a terminal simulator for a low earth orbit satellite constellation communication system is used for simulating a plurality of terminals to communicate with a satellite, the multiple access mode for the communication between the terminal simulator and the satellite comprises one or a combination of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the terminal simulator comprises a terminal uplink and receiving parameter simulation module, a local pps signal synchronization module, a spread spectrum transmitting module and a spread spectrum receiving module, the terminal uplink and receiving parameter simulation module is used for outputting a multiple access control signal which corresponds to a set multiple access mode and is used for terminal uplink and receiving so as to control the spread spectrum transmitting module and the spread spectrum receiving module to work according to the multiple access mode, the spread spectrum receiving module is used for receiving the multiple access control signal and a downlink signal sent by the satellite and demodulating the downlink signal sent by the satellite according to the multiple access control signal, the spread spectrum transmitting module is used for receiving the multiple access control signal and outputting an uplink signal to the satellite, and the local pps signal synchronization module is used for outputting a local pps signal to the uplink terminal and receiving parameter simulation module. Through the novel terminal simulator in the application, the communication between a plurality of simulated terminals and a satellite can be realized by adopting a mode of combining multiple access modes such as time division multiple access, frequency division multiple access, code division multiple access, space division multiple access and the like, so that the communication capacity of a satellite constellation communication system can be improved from a plurality of angles of time, frequency, address and space, the number of terminals which can be simulated by the terminal simulator is greatly increased, the number of users which can be accessed by the satellite constellation communication system is increased, and then the satellite constellation communication system which can be communicated by adopting different multiple access modes and has a large number of users can be simulated and tested, the test efficiency of the satellite constellation communication system is improved, and the problems that the communication between the satellite constellation communication system and different user terminals is realized by adopting the code division multiple access mode in the prior art, the number of the accessible users is too small, and the test efficiency of the communication system is low are solved.
Furthermore, the multiple access control signal output by the uplink and reception parameter simulation module of the terminal comprises a time slot control signal, a carrier frequency control signal, a pseudo code frequency control signal and a pseudo code generator polynomial.
Further, the terminal uplink and reception parameter simulation module includes a read address control module, a terminal uplink and reception parameter ROM, and a terminal uplink and reception parameter analysis module, where the read address control module is configured to output an address to the terminal uplink and reception parameter ROM, and the terminal uplink and reception parameter analysis module is configured to read and analyze multiple access parameters corresponding to the address in the terminal uplink and reception parameter ROM to output a corresponding multiple access control signal.
Furthermore, the spread spectrum transmitting module comprises a Doppler compensation and delay control module, and the Doppler compensation and delay control module is used for compensating Doppler dynamic and satellite-to-ground distance delay output terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words so as to modulate corresponding multiple access control signals used for terminal uplink.
Furthermore, the spread spectrum receiving module comprises a capturing module, and the capturing module is used for capturing the sampled downlink signal, outputting a carrier NCO control word received by the terminal, a pseudo code NCO control word received by the terminal, and a pseudo code phase control signal received by the terminal.
Further, when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same carrier frequency and the same pseudo code, the terminal simulator communicates with the satellite in a time division multiple access manner.
Further, when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same pseudo code and different carrier frequencies, the terminal simulator communicates with the satellite in a frequency division multiple access manner.
Further, when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same carrier frequency and different pseudo codes, the terminal simulator communicates with a satellite in a code division multiple access mode.
Further, when a plurality of terminals simulated by the terminal simulator are located in different beam coverage areas and use the same carrier frequency and the same pseudo code, the terminal simulator adopts a space division multiple access mode to communicate with the satellite.
In addition, a control method for a terminal simulator of a low earth orbit satellite constellation communication system is also provided, the method is implemented based on the terminal simulator for the low earth orbit satellite constellation communication system as described above, and the method includes:
the control terminal uplink and receiving parameter simulation module initializes parameters related to a multiple access mode and outputs corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals used for terminal uplink and multiple access control signals used for terminal receiving;
the terminal simulator simulates a plurality of terminals according to the multiple access control signals, and the plurality of terminals respectively use different multiple access parameters to modulate and demodulate input signals and output signals;
a plurality of terminals simulated by the terminal simulator receive downlink signals sent by a satellite through a spread spectrum receiving module according to corresponding multiple access parameters of the terminals, and demodulate uplink signals according to multiple access control signals received by the terminals;
a plurality of terminals simulated by the terminal simulator output terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words for the multi-address control signals for terminal uplink compensation Doppler dynamics and satellite-to-ground distance delay through a spread spectrum transmitting module;
and modulating the uplink pseudo code NCO control word of the terminal and the uplink carrier NCO control word of the terminal by a plurality of terminals simulated by the terminal simulator according to the corresponding multiple access parameters, and outputting uplink signals to the satellite.
As described above, the present invention has the following advantageous effects:
1) Through the novel terminal simulator in the application, the communication between a plurality of simulated terminals and a satellite can be realized by adopting a mode of combining multiple access modes such as time division multiple access, frequency division multiple access, code division multiple access, space division multiple access and the like, so that the communication capacity of a satellite constellation communication system can be improved from multiple angles of time, frequency, address and space, the number of terminals which can be simulated by the terminal simulator is greatly increased, the number of users which can be accessed by the satellite constellation communication system is increased, and then the satellite constellation communication system which can be communicated by adopting different multiple access modes and has a large number of users can be simulated and tested, the test efficiency of the satellite constellation communication system is improved, and the problems that the communication between the terminal and different user terminals is realized by adopting the code division multiple access mode in the prior art, the number of accessible users is too small, and the test efficiency of the communication system is low are solved.
2) By arranging the terminal uplink and receiving parameter simulation module, the corresponding multiple access control signal can be output by controlling the terminal uplink and receiving parameter simulation module to initialize the parameters related to the multiple access mode so as to realize the multiple access mode of the terminal uplink and the terminal receiving, so that the terminal simulator is switched to the corresponding multiple access mode according to the multiple access mode of the terminal which needs to communicate, and the terminal simulator simulates the communication between the terminal adopting different multiple access modes and the satellite.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiment or the description of the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art it is also possible to derive other drawings from them without inventive effort.
Fig. 1 is a schematic structural diagram of a terminal simulator for a low earth orbit satellite constellation communication system according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a terminal uplink and reception parameter simulation module according to an embodiment of the present disclosure;
fig. 3 is a flowchart of a working procedure of a terminal uplink and reception parameter simulation module according to an embodiment of the present disclosure;
fig. 4 is a schematic diagram of a communication process when a terminal simulator provided in an embodiment of the present disclosure communicates with a satellite in a time division multiple access manner;
fig. 5 is a schematic diagram of a communication process of a terminal simulator communicating with a satellite in a frequency division multiple access manner according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of a communication process when a terminal simulator provided in an embodiment of the present disclosure communicates with a satellite by using code division multiple access;
fig. 7 is a schematic diagram of a communication process when a terminal simulator provided in an embodiment of the present disclosure communicates with a satellite by using space division multiple access;
fig. 8 is a schematic diagram of a communication process when the terminal simulator provided in the embodiment of the present disclosure communicates with a satellite by using a combination of time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access;
fig. 9 is a schematic flowchart of a terminal simulator communicating with a satellite according to an embodiment of the present disclosure.
Wherein the reference numerals in the figures correspond to:
the system comprises a terminal uplink and receiving parameter simulation module 1, a reading address control module 11, a terminal uplink and receiving parameter ROM, a terminal uplink and receiving parameter analysis module 13, a spread spectrum transmitting module 3, a Doppler compensation and delay control module 31, a spread spectrum receiving module 4 and an acquisition module 41.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1:
as shown in fig. 1-8, an embodiment of the present disclosure provides a terminal simulator for a low-earth satellite constellation communication system, where the terminal simulator is configured to simulate a plurality of terminals to communicate with a satellite, a multiple access manner for the terminal simulator to communicate with the satellite includes one or a combination of time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access, the terminal simulator includes a terminal uplink and reception parameter simulation module 1, a local pps signal synchronization module 2, a spread spectrum transmission module 3, and a spread spectrum reception module 4, the terminal uplink and reception parameter simulation module 1 is configured to output a multiple access control signal for terminal uplink and reception corresponding to a set multiple access manner to control the spread spectrum transmission module 3 and the spread spectrum reception module 4 to operate in the multiple access manner, the spread spectrum reception module 4 is configured to receive the multiple access control signal and a downlink signal sent by the satellite and demodulate the downlink signal sent by the satellite according to the multiple access control signal, the spread spectrum transmission module 3 is configured to receive the multiple access control signal and output an uplink signal to the satellite, and the local pps signal synchronization module 2 is configured to output a local pps signal to the terminal uplink and reception parameter simulation module 1.
Specifically, the multiple access control signal comprises a multiple access control signal used for terminal uplink and a multiple access control signal used for terminal reception, the spread spectrum transmitting module 3 receives the multiple access control signal used for terminal uplink and outputs an uplink signal to the satellite, and the spread spectrum receiving module 4 receives the multiple access control signal used for terminal reception and a downlink signal sent by the satellite and demodulates the downlink signal sent by the satellite according to the multiple access control signal used for terminal reception.
Specifically, the principles of time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access are as follows:
time division multiple access is performed on a broadband wireless carrier by dividing time into periodic frames, and dividing each frame into a plurality of time slots (no matter whether the frames or the time slots are mutually non-overlapping), wherein each time slot is a communication channel and is allocated to a user. Multiple users are allowed to access the communication system using the same frequency or code address in different time slices (time slots) to communicate with the satellite.
Frequency division multiple access divides a frequency band into a plurality of channels, and simultaneously, a plurality of different address users use different carriers (channels) to realize multiple access, and only one user's service information can be transmitted in one frequency channel at the same time. The users use channels of different frequencies and therefore do not interfere with each other.
Cdma is an address that is distinguished by different address codes, and each user can communicate using the same frequency band at the same time using different address codes.
Space division multiple access is the use of spatial division to form different channels, with the beams of the antennas on the satellites being directed to different regions of the earth's surface. Users in different areas on the ground do not interfere with each other at the same time, even if they operate using the same frequency.
It should be noted that, in the prior art, a terminal simulator for a low earth orbit satellite communication system generally employs a code division multiple access method to implement communication with a satellite, the number of users is affected by the number of pseudo-random codes, and meanwhile, the system has a small number of accessible users and a low test efficiency of a simulated satellite constellation communication system.
Therefore, the novel terminal simulator is arranged, communication between a plurality of simulated terminals and a satellite can be realized by combining a plurality of multi-access modes such as time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the communication capacity of a satellite constellation communication system can be improved from a plurality of angles of time, frequency, address and space, the number of terminals which can be simulated by the terminal simulator is greatly increased, the number of users which can be accessed by the satellite constellation communication system is increased, then the satellite constellation communication system which can be communicated by adopting different multi-access modes and has a large number of users can be simulated and tested, the test efficiency of the satellite constellation communication system is improved, and the problems that communication between the satellite constellation communication system and different user terminals is realized by adopting the code division multiple access mode in the prior art, the number of accessible users is too small, and the test efficiency of the communication system is low are solved.
Preferably, the multiple access control signal output by the terminal uplink and reception parameter simulation module 1 includes a timeslot control signal, a carrier frequency control signal, a pseudo code frequency control signal, and a pseudo code generator polynomial.
Preferably, as shown in fig. 2, the terminal uplink and reception parameter simulation module 1 includes a read address control module 11, a terminal uplink and reception parameter ROM12, and a terminal uplink and reception parameter analysis module 13, where the read address control module 11 is configured to output an address to the terminal uplink and reception parameter ROM12, a local pps signal is input to the terminal uplink and reception parameter analysis module 13, and the terminal uplink and reception parameter analysis module 13 is configured to read and analyze a multiple access parameter corresponding to the address in the terminal uplink and reception parameter ROM12 to output a corresponding multiple access control signal.
Specifically, the read address control module 11 changes the address value of the read address control module 11 under the control of the data output by the terminal uplink and receive parameter ROM12, the terminal uplink and receive parameter ROM12 stores parameters related to multiple access modes, such as timeslot allocation, pseudo code polynomial, pseudo code initial phase, pseudo code frequency, carrier frequency, etc., the terminal uplink and receive parameter ROM12 outputs multiple access parameters according to the read address, and the terminal uplink and receive parameter parsing module 13 outputs timeslot control signals, pseudo code polynomial and initial phase, pseudo code NCO control words, carrier NCO control words and channel selection signals after parsing the multiple access parameters.
Specifically, the time slot control signal comprises a terminal uplink time slot control signal and a terminal receiving time slot control signal, the pseudo code polynomial and the initial phase comprise a terminal uplink pseudo code polynomial and an initial phase and a terminal receiving pseudo code polynomial and an initial phase, the pseudo code NCO control word comprises a terminal uplink pseudo code NCO control word and a terminal receiving pseudo code NCO control word, the carrier NCO control word comprises a terminal uplink carrier NCO control word and a terminal receiving carrier NCO control word, and the channel selection signal comprises a terminal uplink channel selection signal and a terminal receiving channel selection signal.
Wherein, the terminal uplink time slot control signal, the terminal uplink pseudo code polynomial and initial phase, the terminal uplink pseudo code NCO control word, the terminal uplink carrier NCO control word and the terminal uplink channel selection signal are used for outputting to the spread spectrum emission module 3; the terminal receiving time slot control signal, the terminal receiving pseudo code polynomial and terminal receiving initial phase, the terminal receiving pseudo code NCO control word, the terminal receiving carrier NCO control word and the terminal receiving channel selection signal are used for being output to the spread spectrum receiving module 4.
As shown in fig. 3, the working process of the terminal uplink and receiving parameter simulation module 1 is that, first, the terminal uplink and receiving parameter ROM12 initializes through the core file at the beginning of powering on the low orbit satellite constellation communication system to store multiple access parameters, assigns the initial value of the reading address addr of the terminal uplink and receiving parameter ROM12 to zero, then enters judgment and circulation to judge whether addr is less than or equal to the maximum address that the terminal uplink and receiving parameter ROM12 can read, if yes, the content pointed by the address addr in the terminal uplink and receiving parameter ROM12, that is, multiple access parameters, and analyzes the read multiple access parameters through the terminal uplink and receiving parameter analysis module 13 to output control signals, that is, time slot control signals, pseudo code polynomials, initial phases, pseudo code control words, carrier NCO control words and channel selection signals for terminal uplink and receiving, and then adds the value of the reading address addr to judge again; if not, the value of the read address addr is set to zero and the judgment is carried out again.
Preferably, the spread spectrum transmitting module 3 includes a doppler compensation and delay control module 31, and the doppler compensation and delay control module 31 is configured to compensate the doppler dynamics and the satellite-to-ground distance delay to output the uplink pseudo code NCO control word of the terminal and the uplink carrier NCO control word of the terminal so as to modulate the corresponding multiple access control signal used for uplink of the terminal.
Specifically, the spread spectrum transmission module 3 further includes: the system comprises a terminal uplink coding module, a terminal uplink pseudo code NCO, a pseudo code generator, a forming filter, a terminal uplink carrier NCO, a sine table, a cosine table and a DAC and a channel selection module.
Specifically, the spread spectrum transmitting module 3 is configured to compensate the doppler dynamic and the satellite-to-ground distance delay through the doppler compensation and delay control module 31, perform spreading and modulation on the baseband signal output by the terminal uplink coding module, and output the uplink signal with the doppler dynamic and satellite-to-ground distance delay compensation.
The terminal uplink coding module is used for processing original data codes (such as RS codes, differential codes, convolutional codes and the like) to generate baseband signals; the terminal uplink pseudo code NCO is used for generating corresponding pseudo code frequency according to the terminal uplink pseudo code control word; the pseudo code generator is used for generating a corresponding pseudo code sequence based on pseudo code frequency according to an externally input generator polynomial and an initial phase, and performing spread spectrum modulation on a baseband signal; the shaping filter is used for eliminating intersymbol interference and compressing transmission bandwidth; the terminal uplink carrier NCO is used for generating a corresponding carrier frequency according to the terminal uplink carrier control word; the sine table and the cosine table are respectively used for mapping out corresponding sine signals and cosine signals according to uplink carrier frequencies of the terminal and carrying out up-conversion modulation on baseband signals after spread spectrum modulation; and the DAC and channel selection module is used for selecting a corresponding radio frequency channel according to the uplink channel selection signal of the terminal, converting the up-converted signal into an analog signal and outputting the analog signal through the radio frequency channel.
Preferably, the spread spectrum receiving module 4 includes a capturing module 41, and the capturing module 41 is configured to capture the sampled downlink signal, and output a terminal receive carrier NCO control word, a terminal receive pseudo code NCO control word, and a terminal receive pseudo code phase control signal.
Specifically, the spread spectrum receiving module 4 further includes a code loop module and a carrier loop module, where the code loop module is configured to receive the pseudo code NCO control word by the output terminal, and the carrier loop module is configured to receive the carrier NCO control word by the output terminal, so as to implement modulation of the corresponding multiple access control signal for terminal reception through the common action of the capturing module 41, the code loop module, and the carrier loop module.
Specifically, the spread spectrum receiving module 4 is configured to receive a downlink signal sent by a satellite, perform sampling, capturing, tracking, and demodulate a data frame.
Specifically, the spread spectrum receiving module 4 further includes an ADC and channel selection module, a terminal receiving carrier NCO, a sine table, a cosine table, a terminal receiving pseudo code NCO, a terminal receiving pseudo code generator, a carrier loop module, a code loop module, and a bit synchronization module.
The ADC and channel selection module is used for selecting a corresponding radio frequency channel according to a terminal receiving channel selection signal and converting an analog signal into a digital signal; the terminal receiving carrier NCO is used for generating a corresponding carrier frequency according to the terminal receiving carrier control word; the sine table and the cosine table are respectively used for mapping out corresponding sine signals and cosine signals according to the receiving carrier frequency of the terminal and stripping the carrier waves of the input signals; the terminal receiving pseudo code NCO is used for generating corresponding pseudo code frequency according to the terminal receiving pseudo code control word; the terminal receiving pseudo code generator is used for generating a corresponding pseudo code sequence according to an externally input terminal receiving generating polynomial and an initial phase, generating a corresponding pseudo code sequence according to a terminal receiving pseudo code frequency, and respectively outputting an advanced pseudo code sequence, a prompt pseudo code sequence and a lag pseudo code sequence for tracking a downlink input signal pseudo code; the carrier ring module is used for carrier tracking, namely after carrier capture, the carrier Doppler frequency offset is reduced to a smaller range, carrier tracking is required at this time, the output terminal receives a carrier NOC control word, the terminal receiving carrier frequency is adjusted, and frequency error is further reduced so as to realize correct demodulation; the code loop module is used for tracking a pseudo code of an input signal through a delay locked loop, receiving a pseudo code NCO control word by an output terminal, and adjusting the frequency of a pseudo code sequence received by the terminal to realize correct stripping of the pseudo code of the input signal so as to realize correct demodulation; the bit synchronization module is used for realizing the bit synchronization of the demodulated data and demodulating the correct data bit.
Specifically, the local pps signal synchronization module 2 tracks an externally input pps signal through a phase-locked loop, and outputs a local pps signal synchronized therewith. The externally input pps signal is usually from the output of the GPS/BD navigation satellite time service module to realize the synchronization of the terminal simulator and the Universal Time Coordinated (UTC).
The multiple access mode of the novel terminal simulator can be any one or combination of any several of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access. The following explains the communication process between the novel terminal simulator and the satellite in each multiple access mode and four multiple access modes simultaneously:
in the first embodiment, the terminal simulator simulates that i terminals communicate with the satellite in a time division multiple access manner, and as shown in fig. 4, when the satellite communicates with i terminals, all terminals can use the same carrier frequency and the same pseudo code in the same beam coverage area. Firstly, dividing a communication time interval into i time slots, wherein in each time slot, a satellite only communicates with a corresponding terminal, namely in the time slot 1, the satellite communicates with the terminal 1; in time slot 2, the satellite communicates with terminal 2; during time slot i, the satellite communicates with terminal i. Due to the influence of Doppler frequency offset and satellite-to-ground distance, a certain time delay exists between the data sent by the satellite and the data received by the terminal, or between the data sent by the terminal and the data received by the satellite, so that a period of time is set in each time slot, which is called an effective period. In the communication process, the satellite or the terminal is ensured to receive data in the valid time period. Taking communication between a satellite and a terminal 1 as an example, the satellite simulates Doppler dynamics and satellite-ground distance, a data frame 1 is sent out in a time slot 1, after a certain time delay, the terminal 1 receives the data frame 1 in an effective period of the time slot 1, the Doppler frequency offset and the satellite-ground distance are demodulated and calculated, compensation is carried out, then the data frame 1 is sent out in the next time slot 1, after a certain time delay, the satellite receives the data frame 1 in the effective period of the time slot 1, and the satellite and the terminal 1 complete communication.
In a second embodiment, the terminal simulator simulates that i terminals communicate with the satellite in frequency division multiple access, and as shown in fig. 5, the satellite communicates with j terminals at the same time, and all terminals can be in the same beam coverage area and use the same pseudo code, but they use different carrier frequencies. After the satellite simulates Doppler dynamic and satellite-ground distance, different carrier frequencies are used for simultaneously sending out data frames 1-j, the terminal demodulates corresponding data frames by utilizing respective carrier frequencies, the Doppler frequency offset and the satellite-ground distance are calculated and compensated, the data frames are sent out by the respective carrier frequencies, the satellite demodulates by the corresponding carrier frequencies to obtain the data frames 1-j, and the satellite and each terminal complete communication.
In a third embodiment, the terminal simulator simulates that i terminals communicate with the satellite in cdma, and as shown in fig. 6, the satellite communicates with k terminals at the same time, and all terminals may be in the same beam coverage area and use the same carrier frequency, but they use different pseudo codes. The satellite simulates Doppler dynamics and satellite-ground distance, different pseudo codes are used for spreading frequency and then simultaneously sending out data frames 1-k, the terminal demodulates corresponding data frames by utilizing respective pseudo codes, doppler frequency offset and satellite-ground distance are calculated and compensated, then respective pseudo codes are used for spreading frequency and sending out data frames, the satellite demodulates corresponding pseudo codes to obtain data frames 1-k, and the satellite and each terminal complete communication.
In the fourth embodiment, the terminal simulator simulates that i terminals communicate with the satellite in space division multiple access, and as shown in fig. 7, the satellite communicates with q terminals at the same time, and all terminals use the same carrier frequency and pseudo code, but in different beam coverage areas. After simulating Doppler dynamic and satellite-ground distance, the satellite simultaneously sends out data frames 1-q through different radio frequency channels, the terminal receives corresponding data frames in respective beam coverage areas, calculates Doppler frequency offset and satellite-ground distance and sends out data frames after compensation, the satellite receives the data frames 1-q through corresponding radio frequency channels, and the satellite and each terminal complete communication.
In a fifth embodiment, the terminal simulator simulates i terminals to communicate with the satellite by using a combination of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, as shown in fig. 8, the communication system comprises i time slots, j carrier frequencies, k pseudo codes and q beams, and the terminals (i, j, k, q) communicate with the satellite in the ith time slot, the jth carrier frequency and the kth pseudo code in the qth beam coverage area.
An embodiment of the present specification provides a method for controlling a terminal simulator used in a low earth orbit satellite constellation communication system, where the method is implemented based on the terminal simulator used in the low earth orbit satellite constellation communication system in embodiment 1, and the method includes:
the control terminal uplink and receiving parameter simulation module 1 initializes parameters related to a multiple access mode to output corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals used for terminal uplink and multiple access control signals used for terminal receiving;
the terminal simulator simulates a plurality of terminals according to the multiple access control signals, and the plurality of terminals respectively use different multiple access parameters to modulate and demodulate input signals and output signals;
a plurality of terminals simulated by the terminal simulator receive downlink signals sent by a satellite through the spread spectrum receiving module 4 according to corresponding multiple access parameters, and demodulate uplink signals according to multiple access control signals received by the terminals;
a plurality of terminals simulated by the terminal simulator output terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words for the multi-address control signals for terminal uplink compensation Doppler dynamics and satellite-to-ground distance delay through a spread spectrum transmitting module 3;
and modulating the uplink pseudo code NCO control word of the terminal and the uplink carrier NCO control word of the terminal by a plurality of terminals simulated by the terminal simulator according to the corresponding multiple access parameters, and outputting uplink signals to the satellite.
Specifically, as shown in fig. 9, a terminal uplink and reception parameter simulation module 1 in the terminal simulator initializes parameters related to a multiple access method, such as timeslot allocation, pseudo code polynomial, pseudo code initial phase, pseudo code frequency, carrier frequency, and the like for uplink and reception of the terminal, and outputs a corresponding multiple access control signal according to the parameters; then the terminal simulator simulates a plurality of terminals according to the multiple access control signals, and the terminals respectively use different multiple access parameters to modulate and demodulate input and output signals; each terminal simulated by the terminal simulator receives and demodulates a corresponding downlink signal from a satellite according to the multiple access parameter of the terminal; and finally, after Doppler compensation and delay control are carried out on each terminal simulated by the terminal simulator, modulating and outputting an uplink signal to the satellite according to the multiple access parameters of the terminal simulator.
Although the present invention has been described by way of preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the present invention.
In this document, the terms front, back, upper, lower and the like in the drawings are used for the sake of clarity and convenience only for the components are located in the drawings and the positions of the components relative to each other. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.
The embodiments and features of the embodiments described herein above can be combined with each other without conflict.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (9)
1. A terminal simulator for a low earth orbit satellite constellation communication system, the terminal simulator is used for simulating a plurality of terminals to communicate with a satellite, the multiple access mode of the terminal simulator communicating with the satellite comprises two or more of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the terminal simulator comprises a terminal uplink and receiving parameter simulation module (1), a local pps signal synchronization module (2), a spread spectrum transmitting module (3) and a spread spectrum receiving module (4), the terminal uplink and receiving parameter simulation module (1) is used for outputting a multiple access control signal corresponding to a set multiple access mode and used for terminal uplink and receiving so as to control the spread spectrum transmitting module (3) and the spread spectrum receiving module (4) to work according to the multiple access mode, the spread spectrum receiving module (4) is used for receiving the multiple access control signal and a downlink signal sent by the satellite and demodulating the downlink signal sent by the satellite according to the multiple access control signal, the spread spectrum transmitting module (3) is used for receiving the multiple access control signal and outputting the uplink signal to the satellite, the local pps signal synchronization module (2) is used for outputting the uplink signal and the local simulation parameter (1) sent by the local terminal to the local pps signal synchronization module,
the multiple access control signal output by the terminal uplink and receiving parameter simulation module (1) comprises a time slot control signal, a carrier frequency control signal, a pseudo code frequency control signal and a pseudo code generator polynomial.
2. The terminal simulator for low earth orbit satellite constellation communication system of claim 1, wherein the terminal uplink and reception parameter simulation module (1) comprises a read address control module (11), a terminal uplink and reception parameter ROM (12) and a terminal uplink and reception parameter analysis module (13), the read address control module (11) is configured to output an address to the terminal uplink and reception parameter ROM (12), and the terminal uplink and reception parameter analysis module (13) is configured to read and analyze a multiple access parameter corresponding to the address in the terminal uplink and reception parameter ROM (12) to output a corresponding multiple access control signal.
3. Terminal simulator for low earth orbit satellite constellation communication system according to claim 1, characterized in that the spread spectrum transmission module (3) comprises a doppler compensation and delay control module (31), the doppler compensation and delay control module (31) being adapted to compensate doppler dynamics and satellite to ground distance delay output terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words to modulate corresponding multiple access control signals for terminal uplink.
4. The terminal simulator for low earth orbit satellite constellation communication system of claim 1, wherein the spread spectrum receiving module (4) comprises an acquisition module (41), and the acquisition module (41) is configured to acquire the sampled downlink signal and output a terminal received carrier NCO control word, a terminal received pseudo code NCO control word and a terminal received pseudo code phase control signal.
5. The terminal simulator for a low earth orbit satellite constellation communication system of claim 1, wherein when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same carrier frequency and the same pseudo code, the terminal simulator communicates with the satellite in a time division multiple access manner.
6. The terminal simulator for low earth orbit satellite constellation communication system of claim 1, wherein when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same pseudo code and different carrier frequencies, the terminal simulator communicates with the satellite in frequency division multiple access.
7. The terminal simulator for low earth orbit satellite constellation communication system of claim 1, wherein when a plurality of terminals simulated by the terminal simulator are located in the same beam coverage area and use the same carrier frequency and different pseudo codes, the terminal simulator communicates with the satellite in code division multiple access.
8. The terminal simulator for a low earth orbit satellite constellation communication system of claim 1, wherein when a plurality of terminals simulated by the terminal simulator are located in different beam coverage areas and use the same carrier frequency and the same pseudo code, the terminal simulator communicates with a satellite in a space division multiple access manner.
9. A method for controlling a terminal simulator for a low earth orbit satellite constellation communication system, the method being implemented based on the terminal simulator for a low earth orbit satellite constellation communication system according to any one of claims 1-8, the method comprising:
the method comprises the steps that a control terminal uplink and receiving parameter simulation module (1) initializes parameters related to a multiple access mode and outputs corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals used for terminal uplink and multiple access control signals used for terminal receiving;
the terminal simulator simulates a plurality of terminals according to the multiple access control signals, and the plurality of terminals respectively use different multiple access parameters to modulate and demodulate input signals and output signals;
a plurality of terminals simulated by the terminal simulator receive downlink signals sent by a satellite through a spread spectrum receiving module (4) according to corresponding multiple access parameters of the terminals, and demodulate uplink signals according to multiple access control signals received by the terminals;
a plurality of terminals simulated by the terminal simulator output terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words to a multi-address control signal for terminal uplink compensation Doppler dynamic and satellite-ground distance delay through a spread spectrum transmitting module (3);
and modulating terminal uplink pseudo code NCO control words and terminal uplink carrier NCO control words by a plurality of terminals simulated by the terminal simulator according to corresponding multiple access parameters thereof, and outputting uplink signals to the satellite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111618908.5A CN114301515B (en) | 2021-12-27 | 2021-12-27 | Terminal simulator for low-earth-orbit satellite constellation communication system and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111618908.5A CN114301515B (en) | 2021-12-27 | 2021-12-27 | Terminal simulator for low-earth-orbit satellite constellation communication system and control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114301515A CN114301515A (en) | 2022-04-08 |
| CN114301515B true CN114301515B (en) | 2023-03-28 |
Family
ID=80970179
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111618908.5A Active CN114301515B (en) | 2021-12-27 | 2021-12-27 | Terminal simulator for low-earth-orbit satellite constellation communication system and control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114301515B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1091506A2 (en) * | 1999-10-01 | 2001-04-11 | Ascom Systec AG | A hybrid CDMA and TDMA radio access scheme for personal satellite communication systems |
| CA2446769A1 (en) * | 2001-05-10 | 2002-11-14 | Qualcomm Incorporated | Multi-mode satellite and terrestrial communication device |
| US7292547B1 (en) * | 2002-05-22 | 2007-11-06 | The Directv Group, Inc. | Device and method for nodal multiple access into communications channels |
| CA2885817A1 (en) * | 2012-10-02 | 2014-04-10 | Rearden, Llc | Systems and methods for wireless bacichaul in distributed-input distributed-output wireless systems |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7840178B2 (en) * | 2005-07-12 | 2010-11-23 | Martin E. Hellman | FM broadcast system competitive with satellite radio |
| CN104316938B (en) * | 2014-09-25 | 2016-10-19 | 上海欧科微航天科技有限公司 | A kind of New Satellite simulator for the plesiochronous communication system of low orbit satellite |
| CN105635016B (en) * | 2014-10-29 | 2019-06-21 | 北京信威通信技术股份有限公司 | Support satellite mobile communication system, the method and device of either simplex data collection service |
| CN104378152B (en) * | 2014-11-10 | 2017-12-05 | 上海微小卫星工程中心 | A kind of multiple access method that on-board processing is received based on LEO satellite multi-beam |
| JP6142395B2 (en) * | 2014-11-28 | 2017-06-07 | 株式会社クォリンクス・コーポレーション | Satellite communication simulation system |
| CN111970045B (en) * | 2020-08-17 | 2022-04-12 | 湖南斯北图科技有限公司 | Space-based Internet of things signal processing solution with variable message rate |
-
2021
- 2021-12-27 CN CN202111618908.5A patent/CN114301515B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1091506A2 (en) * | 1999-10-01 | 2001-04-11 | Ascom Systec AG | A hybrid CDMA and TDMA radio access scheme for personal satellite communication systems |
| CA2446769A1 (en) * | 2001-05-10 | 2002-11-14 | Qualcomm Incorporated | Multi-mode satellite and terrestrial communication device |
| US7292547B1 (en) * | 2002-05-22 | 2007-11-06 | The Directv Group, Inc. | Device and method for nodal multiple access into communications channels |
| CA2885817A1 (en) * | 2012-10-02 | 2014-04-10 | Rearden, Llc | Systems and methods for wireless bacichaul in distributed-input distributed-output wireless systems |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114301515A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4194759B2 (en) | System and method for narrowing the frequency uncertainty range of a Doppler shifted signal | |
| EP3353969B1 (en) | Frequency tracking with sparse pilots | |
| AU681483B2 (en) | Method of transmitting and receiving power control messages in a CDMA cellular radio system | |
| RU2256935C2 (en) | System, method and user's terminal in system of unambiguous determination of location with the use of two satellites on lo- altitude near-earth orbit | |
| JP4386574B2 (en) | Multi-layered PN code spreading in multi-user communication systems | |
| CN104297765A (en) | Ground terminal simulator used for low-orbit satellite synchronous communication system | |
| JP2018512798A (en) | Satellite beam power back-off | |
| CN104316938A (en) | Novel satellite simulator for low-earth-orbit satellite quasi-synchronous communication system | |
| Nardin et al. | Empowering the tracking performance of LEO-based positioning by means of meta-signals | |
| CN114362811B (en) | Doppler frequency compensation device and method for space satellite-borne terminal of space satellite | |
| CN105915264B (en) | The method of the double spread-spectrum code signals of multiplexing SMA links | |
| CN112118150B (en) | Satellite internet-based on-orbit testing method and system | |
| CN114301515B (en) | Terminal simulator for low-earth-orbit satellite constellation communication system and control method | |
| WO2001017301A1 (en) | Satellite simulator | |
| CN114301514B (en) | Satellite simulator for low-orbit satellite constellation communication system and control method | |
| KR101987815B1 (en) | massive air-channel simulator for massive MIMO base station with self-calibration | |
| An et al. | Antenna array calibration for IIoT oriented satellites: From orthogonal CDMA to NOMA | |
| KR102129270B1 (en) | method for calibrating I/Q imbalance of massive air-channel simulator | |
| Singh et al. | Spectrumize: Spectrum-efficient Satellite Networks for the Internet of Things | |
| KR102009444B1 (en) | method for calibrating channel reciprocity of massive air-channel simulator | |
| Lacoste et al. | Hybrid single frequency network propagation channel sounding and antenna diversity measurements | |
| Rodríguez-Osorio et al. | ADAM: A realistic implementation for a W-CDMA smart antenna | |
| Zheng et al. | Synthetic Waveform Generation for Satellite, HAPS, and 5G Base Station Positioning Reference Signal Using QuaDRiGa | |
| Musso et al. | Integration of galileo and umts services using a software radio based receiver | |
| da Silva Araujo et al. | Cognitive Radio Strategy Combined with MODCOD Technique to Mitigate Interference on Low Orbit Satellite Downlinks |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |