A method and apparatus for phase tracking for a satellite communication system

Abstract

Embodiments of the present application provide a phase tracking method and device for a satellite communication system, the method comprising: acquiring a frequency offset compensation signal, the frequency offset compensation signal comprising a pilot segment and a data segment; performing demodulation processing on the pilot segment to obtain a demodulated pilot segment; splicing the demodulated pilot segment and the data segment to obtain a spliced signal; performing despreading processing on the spliced signal to obtain a despread signal; performing phase compensation processing on the despread signal to obtain an initial phase compensation signal; performing phase error calculation based on the initial phase compensation signal to obtain a target phase error; and performing phase compensation processing on the initial phase compensation signal based on the target phase error to obtain a target phase compensation signal, aiming to improve the signal-to-noise ratio of the signal and improve the phase tracking performance.

Description

Technical Field

[0001] This application relates to the field of satellite communication technology, and in particular to a phase tracking method and apparatus for satellite communication systems. Background Technology

[0002] In the field of modern communications, broadband spread spectrum communication systems, with their unique signal processing methods and anti-interference capabilities, are widely used for data transmission in various complex environments. Spread spectrum communication, by extending the signal over a wider frequency band, can resist noise and interference to a certain extent, thereby improving the reliability and security of communication. However, under low signal-to-noise ratio conditions, the system faces severe challenges.

[0003] Low signal-to-noise ratio (SNR) environments mean an extremely low ratio of signal power to noise power, significantly amplifying the impact of noise on the signal. In such conditions, the signal's phase information is easily interfered with by noise, leading to increased phase error jitter. Phase tracking is a crucial signal processing step in spread spectrum communication systems, ensuring signal synchronization and demodulation performance by real-time monitoring and correction of phase deviations. However, when phase error jitter is large, phase tracking, typically used for synchronization and parameter estimation in the frame header (the beginning of the signal), suffers from limited signal energy and relatively strong noise interference. This makes it difficult for the phase tracking loop to accurately lock the signal phase, severely hindering the attainment of synchronization.

[0004] Once phase tracking is lost, the system needs to re-enter the acquisition state. This process not only consumes additional time and resources, but may also lead to a significant increase in the error rate of signal demodulation. If the traditional closed-loop phase tracking scheme is continued to be used, relying directly on the frame header for phase tracking, the performance of the spread spectrum communication system under low signal-to-noise ratio conditions will be severely limited. Therefore, the limitations of the existing phase tracking scheme in low signal-to-noise ratio environments have become one of the key factors restricting the performance improvement of broadband spread spectrum communication systems. Summary of the Invention

[0005] The main objective of this application is to propose a phase tracking method and apparatus for satellite communication systems, aiming to improve the signal-to-noise ratio and enhance phase tracking performance.

[0006] To achieve the above objectives, a first aspect of this application proposes a phase tracking method for a satellite communication system, the method comprising:

[0007] Acquire a frequency offset compensation signal, the frequency offset compensation signal including a pilot band and a data band;

[0008] The pilot band is demodulated to obtain a demodulated pilot band;

[0009] The demodulation pilot band and the data segment are spliced ​​together to obtain the spliced ​​signal;

[0010] The spliced ​​signal is despread to obtain the despread signal;

[0011] The despread signal is subjected to phase compensation processing to obtain an initial phase compensation signal;

[0012] The target phase error is obtained by calculating the phase error based on the initial phase compensation signal;

[0013] The initial phase compensation signal is processed based on the target phase error to obtain the target phase compensation signal.

[0014] The method provided in the first aspect can improve the signal-to-noise ratio (SNR) of the frame header signal and enhance the phase tracking performance of the frame header. This overcomes the problem in the prior art where the frame header is directly used for phase tracking in low SNR environments, which makes it difficult for the spread spectrum communication system to adapt to low SNR environments and thus severely limits the performance of the spread spectrum communication system.

[0015] In one possible implementation, the demodulation process of the pilot band to obtain a demodulated pilot band includes:

[0016] Obtain the original baseband signal modulation sequence of the transmitting end of the satellite communication system, and obtain the Gaussian white noise sequence of the channel of the satellite communication system;

[0017] The pilot band is demodulated based on the original baseband signal modulation sequence and the Gaussian white noise sequence to obtain the demodulated pilot band.

[0018] In one possible implementation, the despreading process of the spliced ​​signal to obtain the despread signal includes:

[0019] Obtain the spreading indication, and obtain the spreading factor based on the spreading indication;

[0020] Read the total length of the spliced ​​signal, the total length including the pilot length;

[0021] The spliced ​​signal is despread based on the spreading factor and the pilot length to obtain the despread signal.

[0022] In one possible implementation, the step of calculating the phase error based on the initial phase compensation signal to obtain the target phase error includes:

[0023] The initial phase error is obtained based on the initial phase compensation signal;

[0024] The initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error.

[0025] In one possible implementation, the initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error, including:

[0026] The initial phase compensation signal is split into two signals to obtain the phase compensation split signal.

[0027] The phase-compensated branch signal is passed sequentially through a phase detector, a loop filter, a digitally controlled oscillator, and a phase smoother to update the initial phase error and obtain a new phase error.

[0028] The phase-compensated branch signal is processed using the new phase error to obtain a new phase-compensated signal;

[0029] The new phase compensation signal is split into two signals to obtain a new phase compensation split signal.

[0030] The new phase-compensated branch signal is sequentially passed through the phase detector, the loop filter, the numerically controlled oscillator, and the phase smoother for multiple rounds of error calculation to obtain the target phase error.

[0031] In one possible implementation, the initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error. Before obtaining the target phase error, the process further includes:

[0032] Obtain the spreading indication, and obtain the spreading factor based on the spreading indication;

[0033] Obtain the real and imaginary parameters of the initial phase compensation signal;

[0034] Using a switching controller, the phase detector switches modulation modes according to the spreading factor, the real part parameter, and the imaginary part parameter to obtain a predefined phase detector.

[0035] In one possible implementation, the initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error, including:

[0036] The initial phase compensation signal is passed through the predefined phase detector, which obtains the first phase error based on the real part parameter and the imaginary part parameter.

[0037] The first phase error is passed through the loop filter, which eliminates the high-frequency components in the first phase error to obtain the second phase error;

[0038] The second phase error is passed through the numerically controlled oscillator, which adjusts the second phase error to obtain the third phase error;

[0039] The third phase error is passed through the phase smoother, which performs phase smoothing on the third phase error based on the spread factor to update the initial phase error and obtain the target phase error.

[0040] To achieve the above objectives, a second aspect of this application provides a phase tracking device for a satellite communication system, the device comprising:

[0041] Signal acquisition module: used to acquire frequency offset compensation signal, which includes pilot band and data band;

[0042] Demodulation module: used to perform demodulation processing on the pilot band to obtain a demodulated pilot band;

[0043] splicing module: used to splice the demodulation pilot band and the data segment to obtain a spliced ​​signal;

[0044] Despreading module: used to despread the spliced ​​signal to obtain a despread signal;

[0045] Phase compensation module: used to perform phase compensation processing on the despread signal to obtain an initial phase compensation signal;

[0046] Error calculation module: used to calculate the phase error based on the initial phase compensation signal to obtain the target phase error;

[0047] The phase compensation module is further used to perform phase compensation processing on the initial phase compensation signal based on the target phase error to obtain the target phase compensation signal.

[0048] The device provided in the second aspect can improve the signal-to-noise ratio (SNR) of the frame header signal and enhance the phase tracking performance of the frame header. This overcomes the problem in the prior art where the frame header is directly used for phase tracking in low SNR environments, which makes it difficult for the spread spectrum communication system to adapt to low SNR environments, thus severely limiting the performance of the spread spectrum communication system.

[0049] Thirdly, an electronic device is provided, the electronic device including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the phase tracking method for a satellite communication system as described in any possible implementation of the first aspect.

[0050] Fourthly, a computer-readable storage medium is provided, the storage medium storing a computer program that, when executed by a processor, implements the phase tracking method for a satellite communication system as described in any possible implementation of the first aspect. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in one or more embodiments or prior art of this specification, the accompanying drawings used in the description of one or more embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic flowchart of a phase tracking method for a satellite communication system provided in an embodiment of this application;

[0053] Figure 2 This is a principle block diagram of the phase tracking method for a satellite communication system provided in the embodiments of this application;

[0054] Figure 3 This is a schematic block diagram of the interface of the top-level module of the phase tracking device for a satellite communication system provided in the embodiments of this application;

[0055] Figure 4 This is a structural block diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described one or more embodiments are merely some embodiments of this specification, and not all embodiments. All other embodiments obtained by those skilled in the art based on one or more embodiments of this specification without creative effort should fall within the protection scope of this document.

[0057] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0059] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0060] In communication systems, signal transmission is often affected by various factors, among which relative motion is a significant and undeniable source of interference. When there is relative motion between the transmitter and receiver, the signal frequency and phase will change accordingly, specifically manifested as frequency offset and phase offset. Frequency offset refers to the difference between the carrier frequency of the received signal and the carrier frequency of the transmitted signal, while phase offset refers to the deviation between the phase of the received signal and the phase of the transmitted signal. Failure to effectively correct these offsets will have a severely detrimental impact on the signal transmission quality.

[0061] It should be noted that the embodiments of this application provide a closed-loop phase tracking method. The closed-loop structure uses the phase error information of the feedback carrier to control the local carrier source, so that its output frequency and phase gradually approach the carrier frequency and phase of the received signal. This can achieve real-time phase tracking, reduce data storage, reduce hardware resource consumption, and is suitable for broadband communication systems.

[0062] Figure 1 This is an optional flowchart of a phase tracking method for a satellite communication system provided in an embodiment of this application. Figure 1 The method may include, but is not limited to, steps S100 to S700. Figure 2 This is a principle block diagram of the phase tracking method for satellite communication systems provided in the embodiments of this application.

[0063] Firstly, such as Figure 1 and Figure 2 As shown, a phase tracking method for a satellite communication system is provided, the method comprising:

[0064] S100. Obtain the frequency offset compensation signal, which includes the pilot band and the data band.

[0065] It's important to note that the primary task of phase tracking is to handle residual frequency offset and significant phase noise. Therefore, before performing phase tracking, it's necessary to acquire the frequency offset-compensated signal. By performing frequency offset compensation first, the signal frequency can be adjusted to be close to its original frequency, thereby eliminating the linear phase change. In this way, the phase tracking loop only needs to handle residual frequency offset and significant phase noise, rather than simultaneously handling frequency offset and phase offset, simplifying the phase tracking task and allowing the phase tracking loop to more accurately lock the signal phase, improving tracking accuracy and stability. The frequency offset-compensated signal includes a pilot segment and a data segment. The pilot segment is specifically used for channel estimation; it contains known reference signals. The receiver can use these known signals to estimate the channel characteristics. The data segment's signal transmission relies on the channel estimation results provided by the pilot segment. The receiver uses the channel parameters estimated by the pilot segment to correct and demodulate the data segment to recover the original data. In essence, the pilot segment provides channel estimation and synchronization support for the data segment's transmission, while the data segment relies on the information from the pilot segment to achieve accurate signal recovery and data transmission.

[0066] It should also be noted that in some embodiments, frequency and phase offsets are introduced into the signal during transmission due to relative motion. Carrier synchronization is required to correct these offsets. Therefore, before performing phase tracking, it is necessary to acquire the frequency offset-compensated signal. Acquiring the frequency offset-compensated signal includes, but is not limited to:

[0067] Assume that the signal is subjected to a frequency offset during transmission after entering the channel. and phase bias Due to the influence of this, the sequence form before entering the carrier synchronization module is as follows:

[0068] ,

[0069] in, This represents the sequence of unsigned timing errors after matched filtering. This indicates the phase offset process at the error-free transmitting end, used to ensure that the receiver can correctly demodulate the received signal. This represents the Gaussian white noise loaded in the channel. , This indicates the total length of the observation signal received by the synchronization module. Represent the duration of a symbol, and set... ;

[0070] Assuming the frequency offset estimation yields an estimated frequency offset value of The signal obtained after frequency offset compensation is:

[0071] ,

[0072] In practical systems, the frequency offset estimation result is not exactly equal to the actual frequency offset. Therefore, the signal obtained after frequency offset correction still contains the participating offset frequency, and the residual offset frequency value is expressed as follows: , Let the independent and identically distributed Gaussian random variables be represented. , This indicates the total length of the observation signal received by the synchronization module.

[0073] S200. Demodulate the pilot band to obtain the demodulated pilot band.

[0074] S300: The demodulation pilot band and the data band are spliced ​​together to obtain the spliced ​​signal.

[0075] S400: Despread the spliced ​​signal to obtain the despread signal.

[0076] It should be noted that in spread spectrum communication systems, the frame header is typically located at the beginning of the signal frame structure, followed by the pilot segment, and finally the data segment. The frame header provides the receiver with the starting position and basic parameters of the signal frame. The pilot segment uses known signals to help the receiver estimate channel characteristics. The data segment is the part that actually transmits user data, and its correct demodulation depends on the information provided by the frame header and pilot segment. These signals are used to help the receiver perform initial synchronization and parameter estimation. Using the frame header for phase acquisition ensures that the phase tracking loop is already synchronized when processing the data segment. However, since closed-loop phase tracking is more suitable for conditions where the signal power is greater than the noise power, the traditional scheme of directly relying on the frame header for phase tracking in spread spectrum communication systems has significant limitations under low signal-to-noise ratio conditions. Due to the influence of noise, the phase error jitter is large, phase tracking is difficult to synchronize, and it is prone to loss of lock and reacquisition, thus seriously affecting the demodulation performance of the receiver. Therefore, this application proposes to perform demodulation processing on the pilot segment in the frequency offset compensation signal, and then concatenate the demodulated pilot segment and the data segment in the frequency offset compensation signal to obtain a concatenated signal. The concatenated signal is then despread. Through channel estimation and correction, the pilot segment can reduce the impact of channel characteristics on the frame header segment, improve the synchronization accuracy and detection performance of the frame header segment, solve the problem that the received pilot signal is not suitable for direct despreading, improve the signal-to-noise ratio of the frame header segment signal, and improve the phase tracking performance of the frame header segment.

[0077] S500: Perform phase compensation processing on the despread signal to obtain the initial phase compensation signal.

[0078] It should be noted that phase compensation processing is performed on the despread signal to obtain an initial phase compensation signal, which is used for subsequent phase error calculation. The specific formula is as follows:

[0079] ,

[0080] in, This represents the initial phase compensation signal. Elements representing the despread signal, This represents the initial phase error, with an initial value of 0.

[0081] S600. Calculate the phase error based on the initial phase compensation signal to obtain the target phase error.

[0082] It should be noted that the embodiments of this application provide a closed-loop phase tracking method, which calculates the phase error based on the initial phase compensation signal to obtain the target phase error. This helps to reduce errors in the data transmission process, thereby reducing the bit error rate, improving the accuracy of data transmission, and enabling the system to more accurately synchronize the transmission and reception of signals.

[0083] S700: Perform phase compensation processing on the initial phase compensation signal based on the target phase error to obtain the target phase compensation signal.

[0084] It should be noted that using the target phase error to perform phase compensation processing on the initial phase compensation signal can effectively reduce phase noise and jitter. These factors may increase the bit error rate during signal transmission. However, through phase compensation, the phase of the signal becomes more stable, thereby reducing the bit error rate and improving the quality and reliability of the signal.

[0085] The method provided in the first aspect can improve the signal-to-noise ratio (SNR) of the frame header signal and enhance the phase tracking performance of the frame header. This overcomes the problem in the prior art where the frame header is directly used for phase tracking in low SNR environments, which makes it difficult for the spread spectrum communication system to adapt to low SNR environments and thus severely limits the performance of the spread spectrum communication system.

[0086] In one possible implementation, the demodulation processing of the pilot band to obtain the demodulated pilot band includes: acquiring the original baseband signal modulation sequence of the transmitter of the satellite communication system, and acquiring the Gaussian white noise sequence of the channel of the satellite communication system; and performing demodulation processing on the pilot band according to the original baseband signal modulation sequence and the Gaussian white noise sequence to obtain the demodulated pilot band.

[0087] It should be noted that since the received pilot signal is not suitable for direct despreading, the received pilot band needs to be demodulated first. Specifically, it is first necessary to obtain the original baseband signal modulation sequence from the transmitting end of the satellite communication system and the Gaussian white noise sequence loaded in the channel of the satellite communication system. Then, the pilot band is demodulated based on the obtained original baseband signal modulation sequence and Gaussian white noise sequence. The specific formula is as follows:

[0088] ,

[0089] in, Indicates pilot band, The sequence elements represent the original baseband signal modulation sequence. The sequence elements representing the Gaussian white noise sequence;

[0090] The elements are ,in, , Indicates the total length of the signal. This represents the residual frequency offset. Indicates symbol rate, This indicates a phase shift.

[0091] In one possible implementation, the despreading process of the spliced ​​signal to obtain the despread signal includes: acquiring a spreading indication and acquiring a spreading factor based on the spreading indication; reading the total length of the spliced ​​signal, the total length including the pilot length; and despreading the spliced ​​signal according to the spreading factor and the pilot length to obtain the despread signal.

[0092] It should be noted that despreading the spliced ​​signal, that is, despreading the data segment and the demodulated pilot segment, effectively improves the signal-to-noise ratio (SNR) of the received signal. By optimizing the SNR, despreading the spliced ​​signal can ensure that phase tracking can still operate stably in a low SNR environment. This not only enhances the signal reception quality but also provides a reliable operational basis for phase tracking.

[0093] It should also be noted that despreading the spliced ​​signal first requires obtaining the spreading indicator, which contains the spreading factor. Then, the total length of the spliced ​​signal is read, including the pilot length. Finally, the spliced ​​signal is despread based on the obtained spreading factor and pilot length to obtain the despread signal. The specific formula is as follows:

[0094] ,

[0095] in, Indicates the despread signal. Indicates the spread factor. Indicates the pilot length. The element representing the demodulation pilot band. Elements representing a data segment.

[0096] It should also be noted that the element representation of the despread signal obtained after despreading the spliced ​​signal is as follows: ,in, Elements representing the despread signal, ,when hour, ,when hour, Related to the modulation symbols of the data segment, Indicates the spread factor. Indicates the pilot length. This represents the residual frequency offset. Indicates symbol rate, Indicates phase shift, The sequence element representing the Gaussian white noise sequence is the first... Each element.

[0097] In one possible implementation, such as Figure 2 As shown, the step of calculating the phase error based on the initial phase compensation signal to obtain the target phase error includes: obtaining the initial phase error based on the initial phase compensation signal; and performing multiple rounds of error calculation on the initial phase compensation signal by sequentially passing it through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother to update the initial phase error and obtain the target phase error.

[0098] It should be noted that the closed-loop phase tracking method provided in this application requires obtaining the initial phase error and sequentially passing the initial phase compensation signal through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error. This helps to reduce errors in the data transmission process, thereby reducing the bit error rate, improving the accuracy of data transmission, and enabling the system to more accurately synchronize the transmission and reception of signals.

[0099] In one possible implementation, the step of sequentially passing the initial phase compensation signal through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error includes: performing signal splitting processing on the initial phase compensation signal to obtain a phase compensation split signal; sequentially passing the phase compensation split signal through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother to update the initial phase error to obtain a new phase error; performing phase compensation processing on the phase compensation split signal using the new phase error to obtain a new phase compensation signal; performing signal splitting processing on the new phase compensation signal to obtain a new phase compensation split signal; and sequentially passing the new phase compensation split signal through the phase detector, the loop filter, the numerically controlled oscillator, and the phase smoother for multiple rounds of error calculation to obtain the target phase error.

[0100] It should be noted that, since a larger bit width results in higher accuracy of phase error calculation during phase tracking, this application proposes to perform signal splitting processing on the phase-compensated signal. One output signal is used for output, and this output signal undergoes saturation processing, which involves outputting the signal according to a preset rule. The other output signal is used for subsequent phase error calculation. Specifically, the phase-compensated split signal is passed sequentially through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother to update the initial phase error, resulting in a new phase error. This new phase error is then used to perform phase compensation processing on the phase-compensated split signal to obtain a new phase-compensated signal. This new phase-compensated signal is then further processed by signal splitting to obtain another new phase-compensated split signal. This new phase-compensated split signal is then passed sequentially through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother, and the above steps are repeated for multiple rounds of error calculation to obtain the target phase error. The signal splitting processing method for the phase-compensated signal provided in this application satisfies both the bit width requirements of the subsequent signal processing interface and ensures the accuracy of the phase error.

[0101] In one possible implementation, the initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error. Before obtaining the target phase error, the method further includes: acquiring a spreading indication and acquiring a spreading factor based on the spreading indication; acquiring the real part and imaginary part parameters of the initial phase compensation signal; and using a switching controller to control the phase detector to switch the modulation mode according to the spreading factor, the real part parameters, and the imaginary part parameters to obtain a predefined phase detector.

[0102] It should be noted that, in some embodiments, the phase detector proposed in this application is used to calculate the phase detection error of different modulation schemes. Specifically, the phase detector is switched according to a switching controller, which obtains the real and imaginary parameters of the initial phase compensation signal. Using the switching controller, the phase detector switches modulation schemes based on the spreading factor, the real parameters, and the imaginary parameters, thus obtaining a predefined phase detector. Switching the modulation scheme of the phase detector through the switching controller improves the system's flexibility, making the method provided in this application applicable to different spreading conditions and different modulation schemes.

[0103] It should also be noted that whenever a new signal frame arrives, the switching controller starts a counter to count the counts. When the counter value reaches a specific threshold related to the spreading factor, the switching controller instructs the phase detector to perform a switching operation. The modulation scheme of the phase detector includes, but is not limited to, BPSK, QPSK, 8PSK, and 16APSK. For example, when the count value is within the specific threshold related to the spreading factor, a BPSK phase detector is used; when the count value is greater than the specific threshold related to the spreading factor, the phase detector is switched according to the modulation scheme provided by the switching controller. Furthermore, when the 16APSK phase detector is used in the embodiments of this application, the phase detection algorithm can adopt a simplified constellation diagram algorithm. Since there are many points on the constellation diagram, direct phase estimation is relatively complex. Therefore, using a simplified constellation diagram algorithm can reduce computational complexity.

[0104] In one possible implementation, the step of sequentially passing the initial phase compensation signal through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error includes: passing the initial phase compensation signal through the predefined phase detector, which obtains a first phase error based on the real part parameter and the imaginary part parameter; passing the first phase error through the loop filter, which eliminates high-frequency components in the first phase error to obtain a second phase error; passing the second phase error through the numerically controlled oscillator, which adjusts the second phase error to obtain a third phase error; and passing the third phase error through the phase smoother, which performs phase smoothing processing on the third phase error based on the spreading factor to update the initial phase error and obtain the target phase error.

[0105] It should be noted that the initial phase compensation signal needs to be passed through a phase detector, loop filter, numerically controlled oscillator and phase smoother in multiple rounds of error calculation to obtain the target phase error. This helps to reduce errors in the data transmission process, thereby reducing the bit error rate, improving the accuracy of data transmission, and enabling the system to transmit and receive signals more accurately.

[0106] In some embodiments, the phase detector provided in this application is used to perform phase detection on input signals with different modulation schemes and calculate the phase error. The phase detector performs phase detection on signals with different modulation schemes according to the instructions of the switching controller.

[0107] In some embodiments, the loop filter provided in this application can be a second-order loop filter, used to remove high-frequency components from the error signal output by the phase detector, achieve signal smoothing, ensure loop stability, improve noise suppression performance, and optimize the acquisition and tracking process.

[0108] In some embodiments, the numerically controlled oscillator provided in this application directly synthesizes waveforms of the desired frequency digitally, which has advantages such as high precision, high stability and ease of control.

[0109] In some embodiments, the phase smoother provided in this application performs phase smoothing on the phase error of the numerically controlled oscillator output according to the spread spectrum instruction. The specific formula of the smoothing strategy is as follows:

[0110] ,

[0111] Among them, when the spreading factor is When the phase error is equal to the phase error output of the phase error smoother, the phase error output of the numerically controlled oscillator is the same as the phase error output of the oscillator; when the spread spectrum factor is... When the phase error is at the specified frequency, the phase error output by the phase error smoother is updated every two points; when the spreading factor is 2 or 1, the phase error output by the phase error smoother is updated every four points. Since broadband satellite communication systems in spread spectrum mode need to adapt to lower signal-to-noise ratio conditions, the spreading gain is smaller when the spreading factor is low. Therefore, this application proposes a phase error smoother to cope with sudden interference or large momentum noise, improve the problem of large phase jitter in low signal-to-noise ratio, that is, improve the signal-to-noise ratio state of the signal and improve the phase tracking performance of the broadband spread spectrum communication system.

[0112] To achieve the above objectives, a second aspect of this application provides a phase tracking device for a satellite communication system, the device comprising:

[0113] Signal acquisition module: used to acquire frequency offset compensation signal, which includes pilot band and data band.

[0114] In communication systems, signal transmission is often affected by various factors, among which relative motion is a significant and undeniable source of interference. When there is relative motion between the transmitter and receiver, the signal frequency and phase will change accordingly, specifically manifested as frequency offset and phase offset. Frequency offset refers to the difference between the carrier frequency of the received signal and the carrier frequency of the transmitted signal, while phase offset refers to the deviation between the phase of the received signal and the phase of the transmitted signal. Failure to effectively correct these offsets will have a severely detrimental impact on the signal transmission quality.

[0115] It should be noted that the embodiments of this application provide a closed-loop phase tracking device. The closed-loop structure uses the phase error information of the feedback carrier to control the local carrier source, so that its output frequency and phase gradually approach the carrier frequency and phase of the received signal. This can achieve real-time phase tracking, reduce data storage, reduce hardware resource consumption, and is suitable for broadband communication systems.

[0116] It should also be noted that the main task of phase tracking is to handle residual frequency offset and large phase noise. Therefore, before performing phase tracking, it is necessary to obtain the signal after frequency offset compensation. By performing frequency offset compensation first, the frequency of the signal can be adjusted to be close to its original frequency, thereby eliminating the linear change part of the phase. In this way, the phase tracking loop only needs to handle residual frequency offset and large phase noise, instead of handling frequency offset and phase offset at the same time, which simplifies the phase tracking task and allows the phase tracking loop to lock the phase of the signal more accurately, improving the tracking accuracy and stability.

[0117] Demodulation module: used to perform demodulation processing on the pilot band to obtain a demodulated pilot band.

[0118] The splicing module is used to splice the demodulation pilot band and the data segment to obtain a spliced ​​signal.

[0119] Despreading module: used to despread the spliced ​​signal to obtain a despread signal.

[0120] It should be noted that in spread spectrum communication systems, the frame header typically contains synchronization and pilot signals. These signals are used to assist the receiver in initial synchronization and parameter estimation. Using the frame header for phase acquisition ensures that the phase tracking loop is synchronized when processing the data segment. However, since closed-loop phase tracking is more suitable for conditions where signal power is greater than noise power, the traditional scheme of directly relying on the frame header for phase tracking in spread spectrum communication systems has significant limitations under low signal-to-noise ratio (SNR) conditions. Due to the influence of noise, phase error jitter is large, making it difficult for phase tracking to enter a synchronized state, and it is prone to loss of lock and reacquisition, thus seriously affecting the demodulation performance of the receiver. Therefore, this application proposes to demodulate the pilot segment in the frequency offset compensation signal, concatenate the demodulated pilot segment with the data segment in the frequency offset compensation signal to obtain a concatenated signal, and then despread the concatenated signal. This solves the problem that the received pilot signal is not suitable for direct despreading, improves the SNR of the frame header signal, and enhances the phase tracking performance of the frame header.

[0121] Phase compensation module: used to perform phase compensation processing on the despread signal to obtain an initial phase compensation signal.

[0122] Error calculation module: used to calculate the phase error based on the initial phase compensation signal to obtain the target phase error.

[0123] The phase compensation module is further used to perform phase compensation processing on the initial phase compensation signal based on the target phase error to obtain the target phase compensation signal.

[0124] The device provided in the second aspect can improve the signal-to-noise ratio (SNR) of the frame header signal and enhance the phase tracking performance of the frame header. This overcomes the problem in the prior art where the frame header is directly used for phase tracking in low SNR environments, which makes it difficult for the spread spectrum communication system to adapt to low SNR environments, thus severely limiting the performance of the spread spectrum communication system.

[0125] It should also be noted that the phase tracking device for satellite communication systems provided in this application embodiment further includes a top-level phase tracking module, such as... Figure 3 As shown, Figure 3This is a schematic block diagram of the interface of the top-level module (PHASE_TRACK_TOP) of the phase tracking device for a satellite communication system provided in the embodiments of this application. Specifically, it includes a reset signal rst, a system clock clk, 8-bit I-channel and 8-bit Q-channel data I_data_i and I_data_q, input data enable I_data_en, input data divider clock I_data_vld, and outputs including 8-bit I-channel and 8-bit Q-channel data O_data_i and O_data_q, output data enable O_data_en, and output data divider clock O_data_vld.

[0126] This application also provides an electronic device, such as... Figure 4 As shown, the electronic device 1400 includes:

[0127] One or more processors 1410;

[0128] The memory 1420 stores one or more programs that, when executed by one or more processors 1410, enable the one or more processors 1410 to implement the phase tracking method for a satellite communication system provided in any embodiment of this application.

[0129] Memory 1420, as a non-transitory network system, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory 1420 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory 1420 may optionally include remotely located memories 1420 relative to processor 1410, which can be connected to processor 1410 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0130] The memory 1420 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1420 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1420 and is called and executed by the processor 1410.

[0131] The processor 1410 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0132] In some embodiments, the electronic device further includes:

[0133] Input / output interfaces are used to implement information input and output;

[0134] The communication interface is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0135] The bus transmits information between various components of the device (e.g., processor 1410, memory 1420, input / output interfaces, and communication interfaces);

[0136] The processor 1410, memory 1420, input / output interface, and communication interface can communicate with each other within the device via a bus.

[0137] An embodiment of this application also provides a computer-readable storage medium storing computer-executable instructions for executing a phase tracking method for a satellite communication system provided in any embodiment of this application.

[0138] An embodiment of this application also provides a computer program product, including a computer program or computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the computer device to perform a phase tracking method for a satellite communication system provided in any embodiment of this application.

[0139] The system architecture and application scenarios described in this application are intended to more clearly illustrate the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that as system architectures evolve and new application scenarios emerge, the technical solutions provided in this application are also applicable to similar technical problems.

[0140] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0141] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0142] The above description, with reference to the accompanying drawings, illustrates some embodiments of this application, but does not limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of this invention should be considered within the scope of this application.

[0143] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0144] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0145] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0146] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0147] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0148] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A phase tracking method for a satellite communication system, characterized in that, The method includes: Acquire a frequency offset compensation signal, the frequency offset compensation signal including a pilot band and a data band; The pilot band is demodulated to obtain a demodulated pilot band; The demodulation pilot band and the data segment are spliced ​​together to obtain the spliced ​​signal; The spliced ​​signal is despread to obtain the despread signal; The despread signal is subjected to phase compensation processing to obtain an initial phase compensation signal; The target phase error is obtained by calculating the phase error based on the initial phase compensation signal; The initial phase compensation signal is processed based on the target phase error to obtain the target phase compensation signal.

2. The method according to claim 1, characterized in that, The process of demodulating the pilot band to obtain the demodulated pilot band includes: Obtain the original baseband signal modulation sequence of the transmitting end of the satellite communication system, and obtain the Gaussian white noise sequence of the channel of the satellite communication system; The pilot band is demodulated based on the original baseband signal modulation sequence and the Gaussian white noise sequence to obtain the demodulated pilot band.

3. The method according to claim 1, characterized in that, The process of despreading the spliced ​​signal to obtain the despread signal includes: Obtain the spreading indication, and obtain the spreading factor based on the spreading indication; Read the total length of the spliced ​​signal, the total length including the pilot length; The spliced ​​signal is despread based on the spreading factor and the pilot length to obtain the despread signal.

4. The method according to claim 1, characterized in that, The step of calculating the target phase error based on the initial phase compensation signal includes: The initial phase error is obtained based on the initial phase compensation signal; The initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a numerically controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error.

5. The method according to claim 4, characterized in that, The process of sequentially passing the initial phase compensation signal through a phase detector, a loop filter, a digitally controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error includes: The initial phase compensation signal is split into two signals to obtain the phase compensation split signal. The phase-compensated branch signal is passed sequentially through a phase detector, a loop filter, a digitally controlled oscillator, and a phase smoother to update the initial phase error and obtain a new phase error. The phase-compensated branch signal is processed using the new phase error to obtain a new phase-compensated signal; The new phase compensation signal is split into two signals to obtain a new phase compensation split signal. The new phase-compensated branch signal is sequentially passed through the phase detector, the loop filter, the numerically controlled oscillator, and the phase smoother for multiple rounds of error calculation to obtain the target phase error.

6. The method according to claim 4, characterized in that, The initial phase compensation signal is sequentially passed through a phase detector, a loop filter, a digitally controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error. Before obtaining the target phase error, the process further includes: Obtain the spreading indication, and obtain the spreading factor based on the spreading indication; Obtain the real and imaginary parameters of the initial phase compensation signal; Using a switching controller, the phase detector switches modulation modes according to the spreading factor, the real part parameter, and the imaginary part parameter to obtain a predefined phase detector.

7. The method according to claim 6, characterized in that, The process of sequentially passing the initial phase compensation signal through a phase detector, a loop filter, a digitally controlled oscillator, and a phase smoother for multiple rounds of error calculation to update the initial phase error and obtain the target phase error includes: The initial phase compensation signal is passed through the predefined phase detector, which obtains the first phase error based on the real part parameter and the imaginary part parameter. The first phase error is passed through the loop filter, which eliminates the high-frequency components in the first phase error to obtain the second phase error; The second phase error is passed through the numerically controlled oscillator, which adjusts the second phase error to obtain the third phase error; The third phase error is passed through the phase smoother, which performs phase smoothing on the third phase error based on the spread factor to update the initial phase error and obtain the target phase error.

8. A phase tracking device for a satellite communication system, characterized in that, The device includes: Signal acquisition module: used to acquire frequency offset compensation signal, which includes pilot band and data band; Demodulation module: used to perform demodulation processing on the pilot band to obtain a demodulated pilot band; splicing module: used to splice the demodulation pilot band and the data segment to obtain a spliced ​​signal; Despreading module: used to despread the spliced ​​signal to obtain a despread signal; Phase compensation module: used to perform phase compensation processing on the despread signal to obtain an initial phase compensation signal; Error calculation module: used to calculate the phase error based on the initial phase compensation signal to obtain the target phase error; The phase compensation module is further used to perform phase compensation processing on the initial phase compensation signal based on the target phase error to obtain the target phase compensation signal.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the phase tracking method for a satellite communication system as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the phase tracking method for a satellite communication system as described in any one of claims 1 to 7.

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