Intelligent adjustable high-speed coherent optical communication network measurement and control integration method

Abstract

This invention relates to an intelligent, adjustable, high-speed coherent optical communication network measurement and control integration method, belonging to the field of satellite communication technology. It solves the problems of poor flexibility in static routing and reduced ground controllability caused by distributed algorithms in traditional satellite networks. During the transmission phase, the invention implements channel coding (LDPC coding), framing, constellation mapping (BPSK modulation), and digital-to-analog conversion-driven modulation (specifically, a Mach-Zehnder modulator). During the reception phase, the signal is acquired through a dual-polarized coherent receiver, and after polarization correction / frequency offset compensation, the synchronization and tracking unit, in conjunction with the digital channel processing unit, performs deframing, deinterleaving, and LDPC decoding to obtain user data. Furthermore, it integrates communication ranging by extracting the time of flight. This invention is primarily applied in satellite communication.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology. Background Technology

[0002] Most current satellite network systems, such as the Iridium system, use static route snapshots to ensure network reliability and controllability. However, the inflexibility of traditional control structures makes it impossible to meet requirements for service load balancing, node failures, and network scalability. In recent years, many dynamic routing algorithms using distributed link-state collection and route calculation have been proposed. While these algorithms can quickly adapt to changes in network services and link failures, they reduce the controllability of the satellite network from the ground control center. Each satellite cannot easily obtain full network information, forcing it to optimize routes and configuration strategies locally. Summary of the Invention

[0003] The purpose of this invention is to address the problems of poor flexibility in static routing of traditional satellite networks and reduced ground controllability due to distributed algorithms. This invention provides an intelligent, adjustable, high-speed coherent optical communication network measurement and control integrated method.

[0004] An intelligent, adjustable, high-speed coherent optical communication network measurement and control integrated method is applied to satellite communication networks. The method includes a transmission phase and a reception phase.

[0005] The launch phase includes:

[0006] After channel coding and interleaving of user data, physical frames are formed according to the frame structure. After framing, the data is mapped according to the constellation diagram, and then the signal output after digital channel processing is modulated into signal light after digital-to-analog conversion. The user data can be dynamic routing data obtained by the operation coordination center based on the real-time global network view and performing centralized dynamic routing calculation. The dynamic routing data is used to realize on-orbit reconfiguration.

[0007] The receiving phase includes:

[0008] Signal input unit: used to extract the intermediate frequency signal obtained by photoelectric conversion after coherently mixing the signal light in space with the local oscillator light through the receiver, and to perform analog-to-digital conversion on the obtained I-channel and Q-channel analog signals in the X and Y polarization directions to obtain digital I-channel baseband signal and digital Q-channel baseband signal;

[0009] The digital channel processing unit is used to perform polarization correction on the digital I baseband signal and the digital Q baseband signal, and then combine the two baseband signals into a single IQ signal.

[0010] The synchronization and tracking unit is used to detect whether user data has arrived based on the correlation between a single IQ signal and a local preamble signal. After determining that the data has arrived, the unit performs frequency offset estimation on the single IQ signal and sends the frequency offset estimation result to the digital channel processing unit. It is also used to perform signal bit synchronization detection based on the frequency offset estimation result, use the obtained bit-synchronized signal to estimate phase deviation and timing deviation, and send the phase deviation and timing deviation estimation results to the ranging unit.

[0011] The digital channel processing unit is also used to correct the frequency offset of a single IQ signal based on the frequency offset estimation result, and to correct the timing of the frequency offset corrected signal using the timing deviation estimation result. After interpolation, the timing corrected signal is divided into two paths. One path is sent to the deframe unit as the first corrected signal after being aligned with the signal at the given optimal sampling point, and the other path is sent to the ranging unit as the second corrected signal.

[0012] The deframe unit extracts data segments from the received first modified signal according to the physical frame structure;

[0013] The deinterleaving unit is used to deinterleave the deframed data;

[0014] The channel decoding unit is used to decode the deinterleaved data and output user data;

[0015] The ranging unit is used to determine the flight time based on the second corrected signal and the phase and timing deviation estimation results to achieve ranging.

[0016] Preferably, during the transmission phase, channel coding is performed using LDPC codes conforming to the CCSDS131.1-O-2 standard, and the encoded data is scrambled.

[0017] Preferably, the implementation method of mapping the framed data according to the constellation diagram is as follows: the constellation mapping between the data segment and the synchronization preamble in the frame structure of the framed data is BPSK mapping.

[0018] Preferably, the digital channel processing methods during the transmission phase include sampling rate conversion and spectrum shaping.

[0019] Preferably, the signal light is modulated using a Mach-Zehnder modulator during the transmission phase.

[0020] Preferably, the implementation methods for electrical signal extraction in the receiving stage include:

[0021] Intermediate frequency amplification, filtering, and IQ quadrature demodulation are performed sequentially.

[0022] Preferably, the decoding of the deinterleaved data is performed by decoding according to the LDPC code of the CCSDS131.1-O-2 standard.

[0023] Preferably, the implementation methods for signal bit synchronization detection based on the frequency offset estimation results include:

[0024] The frequency offset estimation results provide a basis for sampling symbol alignment for bit synchronization detection, thereby enabling signal bit synchronization detection.

[0025] Preferably, the implementation method for estimating phase and timing deviations using the obtained bit-synchronized signal includes:

[0026] The deviation between the phase of the bit-synchronized signal and the local reference phase is used as the phase deviation estimation result;

[0027] The deviation between the actual sampling time of the signal after bit synchronization and the given sampling time is used as the timing deviation estimation result.

[0028] Preferably, the frequency offset estimation result is also used to coordinate the control of the local oscillator wavelength control module to fine-tune the local oscillator wavelength.

[0029] The beneficial effects of this invention are:

[0030] This invention provides an intelligent, tunable, high-speed coherent optical communication network measurement and control integrated method. During the transmission phase, it implements channel coding (LDPC coding), framing, constellation mapping (BPSK modulation), and digital-to-analog conversion-driven modulation (specifically, a Mach-Zehnder modulator). During the reception phase, the signal is acquired through a dual-polarized coherent receiver, and after polarization correction / frequency offset compensation, the synchronization and tracking unit, in conjunction with the digital channel processing unit, performs deframing, deinterleaving, and LDPC decoding to obtain user data. Furthermore, it integrates communication and ranging by extracting the time of flight. In addition to calculating user data, this invention can also achieve ranging. On-orbit reconfiguration is achieved through user data transmission, significantly improving network dynamism, receiver sensitivity, and controllability at the ground center.

[0031] Innovatively, dual data signals are output to the demodulation and ranging units respectively. In practical applications, the frequency offset estimation results are also used to coordinate the control of the local oscillator wavelength control module, and the local oscillator wavelength is finely adjusted to ensure that the signal can be quantized. Attached Figure Description

[0032] Figure 1 This is a block diagram of the architecture of a high-speed laser coherent communication system.

[0033] Figure 2 This is a schematic diagram illustrating the principle of the launch phase.

[0034] Figure 3 This is a schematic diagram illustrating the principle of the receiving phase;

[0035] Figure 4 is a schematic diagram of the collaborative operation of the synchronization and tracking unit and the digital channel processing unit. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0039] A high-speed coherent laser communication system mainly consists of two parts: a transmitting unit and a receiving unit. A block diagram of the coherent communication system can be found here. Figure 1 As shown. The basic principle of a coherent laser communication system is as follows: the baseband signal is loaded onto a highly coherent signal light, modulated (amplitude, phase, and frequency) by a modulator, and then transmitted through an optical antenna. The coherent receiver collects the spatial optical signal and sends it to an optical mixer, where it is mixed with the local oscillator light generated by a local oscillator laser. The mixture is then photoelectrically converted by a photodetector to obtain a difference frequency signal, commonly referred to as the intermediate frequency (IF) signal. This signal undergoes subsequent electrical processing, including IF amplification, filtering, and demodulation, to ultimately reconstruct the baseband signal. Using coherent spatial optical communication can significantly improve the sensitivity of the optical receiver. Based on the above, this invention provides an integrated measurement and control method for an intelligent, adjustable, high-speed coherent optical communication network.

[0040] Detailed Implementation Method 1, see [link / reference] Figure 1 This embodiment describes an intelligent, adjustable, high-speed coherent optical communication network measurement and control integrated method, which is applied in a satellite communication network. The method includes a transmission phase and a reception phase.

[0041] See Figure 2 The launch phase includes:

[0042] After channel coding and interleaving of user data, physical frames are formed according to the frame structure. After framing, the data is mapped according to the constellation diagram, and then the signal output after digital channel processing is modulated into signal light after digital-to-analog conversion. The user data can be dynamic routing data obtained by the operation coordination center based on the real-time global network view and performing centralized dynamic routing calculation. The dynamic routing data is used to realize on-orbit reconfiguration.

[0043] See Figure 3 The receiving phase includes:

[0044] Signal input unit: used to extract the intermediate frequency signal obtained by photoelectric conversion after coherently mixing the signal light in space with the local oscillator light through the receiver, and to perform analog-to-digital conversion on the obtained I-channel and Q-channel analog signals in the X and Y polarization directions to obtain digital I-channel baseband signal and digital Q-channel baseband signal;

[0045] See Figure 4 The digital channel processing unit is used to perform polarization correction on the digital I baseband signal and the digital Q baseband signal, and then combine the two baseband signals into a single IQ signal. Figure 4 In this context, the digital I baseband signal and the digital Q baseband signal are the dual-polarized digital IQ signals;

[0046] The synchronization and tracking unit is used to detect whether user data has arrived based on the correlation between a single IQ signal and a local preamble signal. After determining that the data has arrived, the unit performs frequency offset estimation on the single IQ signal and sends the frequency offset estimation result to the digital channel processing unit. It is also used to perform signal bit synchronization detection based on the frequency offset estimation result, use the obtained bit-synchronized signal to estimate phase deviation and timing deviation, and send the phase deviation and timing deviation estimation results to the ranging unit.

[0047] The digital channel processing unit is also used to correct the frequency offset of a single IQ signal based on the frequency offset estimation result, and to correct the timing of the frequency offset corrected signal using the timing deviation estimation result. After interpolation, the timing corrected signal is divided into two paths. One path is sent to the deframe unit as the first corrected signal after being aligned with the signal at the given optimal sampling point, and the other path is sent to the ranging unit as the second corrected signal.

[0048] The deframe unit extracts data segments from the received first modified signal according to the physical frame structure;

[0049] The deinterleaving unit is used to deinterleave the deframed data;

[0050] The channel decoding unit is used to decode the deinterleaved data and output user data;

[0051] The ranging unit is used to determine the flight time based on the second corrected signal and the phase and timing deviation estimation results to achieve ranging.

[0052] This invention employs a high-speed coherent communication architecture, divided into a transmission phase and a reception phase, implemented by a transmission unit and a reception unit, respectively. The transmission phase implements channel coding (LDPC coding), framing, constellation mapping (BPSK modulation), and digital-to-analog conversion-driven modulation (specifically, a Mach-Zehnder modulator). The reception phase acquires the signal through a dual-polarized coherent receiver, and after polarization correction / frequency offset compensation, the synchronization and tracking unit, in conjunction with the digital channel processing unit, performs deframing, deinterleaving, and LDPC decoding. Furthermore, the integration of communication and ranging is achieved by extracting the time of flight. The determination of the time of flight for ranging can be implemented using existing technologies.

[0053] This invention innovatively outputs dual data signals to the demodulation and ranging units separately, enabling synchronous deviation feedback to correct accumulated errors. In practical applications, the frequency offset estimation result is also used to collaboratively control the local oscillator wavelength control module, fine-tuning the local oscillator wavelength to ensure signal quantization. This invention significantly improves network dynamics, receiver sensitivity, and the controllability of the ground center.

[0054] This invention can realize an integrated hardware architecture of communication, telemetry and control, and ranging through a ground control center. In addition to calculating user data, it can also realize communication ranging by extracting flight time.

[0055] Specifically, user data can be dynamic routing data obtained by the operation coordination center through centralized dynamic routing calculation based on the real-time global network view. The dynamic routing data is used to achieve on-orbit reconfiguration.

[0056] Furthermore, during the transmission phase, channel coding is performed using LDPC codes conforming to the CCSDS131.1-O-2 (8160, 7136) standard, and the encoded data is scrambled.

[0057] Furthermore, during the launch phase, the implementation method for mapping the framed data according to the constellation diagram is as follows: the data segments in the frame structure of the framed data and the constellation mapping of the synchronization preamble are BPSK mapping.

[0058] Furthermore, the digital channel processing methods during the transmission phase include sampling rate conversion and spectrum shaping.

[0059] Furthermore, the signal light is modulated using a Mach-Zehnder modulator during the transmission phase.

[0060] Furthermore, the implementation methods for electrical domain signal extraction in the receiving phase include:

[0061] Intermediate frequency amplification, filtering, and IQ quadrature demodulation are performed sequentially.

[0062] In practical applications, the decoding of deinterleaved data is performed using LDPC codes based on the CCSDS131.1-O-2 (8160, 7136) standard.

[0063] Furthermore, based on the frequency offset estimation results, the methods for achieving signal bit synchronization detection include:

[0064] The frequency offset estimation results provide a basis for sampling symbol alignment for bit synchronization detection, thereby enabling signal bit synchronization detection.

[0065] Furthermore, the methods for estimating phase and timing deviations using the obtained bit-synchronized signal include:

[0066] The deviation between the phase of the bit-synchronized signal and the local reference phase is used as the phase deviation estimation result;

[0067] The deviation between the actual sampling time of the signal after bit synchronization and the given sampling time is used as the timing deviation estimation result.

[0068] In practical applications, software-adjustable high-speed coherent communication is mainly implemented by the communication control unit. The method of this invention can be integrated into the communication control unit, which can integrate coherent communication electrical signal transmission (DAC) and reception functions. The optical transmission unit board realizes signal LD ​​driving, RF driving, modulator and bias control; the receiving unit board can output I and Q signals in the X / Y polarization direction through the coherent receiver, which are then pre-filtered and ADC converted before being input to the FPGA for signal processing to realize signal decoding and ranging.

[0069] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. An intelligent, adjustable, high-speed coherent optical communication network measurement and control integrated method, characterized in that, Its application in satellite communication networks includes a transmission phase and a reception phase; The launch phase includes: After channel coding and interleaving of user data, physical frames are formed according to the frame structure. After framing, the data is mapped according to the constellation diagram, and then the signal output after digital channel processing is modulated into signal light after digital-to-analog conversion. The user data can be dynamic routing data obtained by the operation coordination center based on the real-time global network view and performing centralized dynamic routing calculation. The dynamic routing data is used to realize on-orbit reconfiguration. The receiving phase includes: Signal input unit: used to extract the intermediate frequency signal obtained by photoelectric conversion after coherently mixing the signal light in space with the local oscillator light through the receiver, and to perform analog-to-digital conversion on the obtained I-channel and Q-channel analog signals in the X and Y polarization directions to obtain digital I-channel baseband signal and digital Q-channel baseband signal; The digital channel processing unit is used to perform polarization correction on the digital I baseband signal and the digital Q baseband signal, and then combine the two baseband signals into a single IQ signal. The synchronization and tracking unit is used to detect whether user data has arrived based on the correlation between a single IQ signal and a local preamble signal. After determining that the data has arrived, the unit performs frequency offset estimation on the single IQ signal and sends the frequency offset estimation result to the digital channel processing unit. It is also used to perform signal bit synchronization detection based on the frequency offset estimation result, use the obtained bit-synchronized signal to estimate phase deviation and timing deviation, and send the phase deviation and timing deviation estimation results to the ranging unit. The digital channel processing unit is also used to correct the frequency offset of a single IQ signal based on the frequency offset estimation result, and to correct the timing of the frequency offset corrected signal using the timing deviation estimation result. After interpolation, the timing corrected signal is divided into two paths. One path is sent to the deframe unit as the first corrected signal after being aligned with the signal at the given optimal sampling point, and the other path is sent to the ranging unit as the second corrected signal. The deframe unit extracts data segments from the received first modified signal according to the physical frame structure; The deinterleaving unit is used to deinterleave the deframed data; The channel decoding unit is used to decode the deinterleaved data and output user data; The ranging unit is used to determine the flight time based on the second corrected signal and the phase and timing deviation estimation results to achieve ranging.

2. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, During the transmission phase, channel coding is performed using LDPC codes conforming to the CCSDS131.1-O-2 standard, and the encoded data is then scrambled.

3. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The implementation method of mapping the framed data according to the constellation diagram is as follows: the constellation mapping between the data segment and the synchronization preamble in the frame structure of the framed data is BPSK mapping.

4. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The digital channel processing methods during the transmission phase include sampling rate conversion and spectrum shaping.

5. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The signal light is modulated using a Mach-Zehnder modulator during the transmission phase.

6. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The methods for extracting electrical signals during the receiving phase include: Intermediate frequency amplification, filtering, and IQ quadrature demodulation are performed sequentially.

7. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The decoding of the deinterleaved data is performed using LDPC codes based on the CCSDS131.1-O-2 standard.

8. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, Based on the frequency offset estimation results, the methods for achieving signal bit synchronization detection include: The frequency offset estimation results provide a basis for sampling symbol alignment for bit synchronization detection, thereby enabling signal bit synchronization detection.

9. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The methods for estimating phase and timing deviations using the obtained bit-synchronized signal include: The deviation between the phase of the bit-synchronized signal and the local reference phase is used as the phase deviation estimation result; The deviation between the actual sampling time of the signal after bit synchronization and the given sampling time is used as the timing deviation estimation result.

10. The intelligent adjustable high-speed coherent optical communication network measurement and control integrated method according to claim 1, characterized in that, The frequency offset estimation results are also used to coordinate the control of the local oscillator wavelength control module to fine-tune the local oscillator wavelength.

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