Service-adaptive satellite-borne non-uniform multicarrier demodulation device

Abstract

The invention discloses a service-adaptive satellite-borne non-uniform multicarrier demodulation device, and belongs to the field of digital signal processing. The method comprises the following steps of: firstly, performing orthogonal down-conversion and resampling filtering processing on a digital intermediate frequency signal sampled by an ADC (Analog to Digital Converter), processing the digital intermediate frequency signal by a non-uniform channelization splitter, and then serially outputting the digital intermediate frequency signal to a spread spectrum ratio self-adaptive variable burst capturer according to fixed quadruple sampling to capture a leading head and identify the spread spectrum ratio; the method comprises the following steps: completing symbol synchronization and de-spreading processing on an input signal according to a spread spectrum ratio, then completing carrier coarse synchronization and pattern word identification, completing modulation mode identification and carrier synchronization according to a pattern word, performing channel decoding through a multi-mode decoder to recover to an information bit stream, and outputting the information bit stream. And the information bit stream is sent to a service frame recombination processor for search identification and recombination splicing, and output is carried out after whole-frame CRC check is carried out. The method has the advantages of flexibility in use, low resource occupation and capability of realizing adaptive demodulation of variable-rate, multi-modulation-mode and multi-coding-mode service transmission signals without parameter configuration.

Description

Technical Field

[0001] This invention relates to the field of spaceborne communication technology, and in particular to a service-adaptive non-uniform multi-carrier demodulation device. It is suitable for adaptive processing of terminal communication services with different rates, apertures, and mobility in broadband satellite communication processing payloads. Background Technology

[0002] Most existing spaceborne demodulators demodulate communication services by receiving parameter configuration commands or configuration frames. Signals with different spreading ratios and modulation / coding schemes require configuration and switching via remote control commands. However, this parameter configuration method suffers from drawbacks in practical applications, including low bandwidth utilization (carrier frequencies must be switched according to commands or even remain fixed), poor compatibility with terminals of varying capabilities, and inflexible terminal networking. Furthermore, it cannot adjust parameters in real time based on satellite link quality (rain attenuation, obstruction, and interference, etc.). These shortcomings limit the flexibility of current satellite communication services and fail to meet the communication service requirements of future broadband satellite communication systems. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a service-adaptive spaceborne non-uniform multi-carrier demodulation device, which is flexible in use, occupies low resources, and can realize a universal design for adaptive demodulation of service transmission signals with variable rate, multiple modulation methods and multiple coding methods without parameter configuration.

[0004] The objective of this invention is achieved as follows: A service-adaptive spaceborne non-uniform multicarrier demodulation device includes an improved CIC resampling filter 1, a non-uniform channelization splitter 2, a spreading ratio adaptive variable burst capture unit 3, an adaptive demodulation synchronizer 4, a multi-mode decoder 5, and a service frame reassembly processor 6; wherein, The improved CIC resampling filter 1 performs orthogonal downconversion on the digital intermediate frequency signal sampled by the ADC to obtain a digital baseband signal, and performs resampling filtering on non-uniform multicarrier digital baseband signals with different sampling rates, and sends them to the non-uniform channelization splitter 2. Non-uniform channelization splitter 2 processes the input non-uniform multicarrier digital baseband signal, and performs channelization processing on the input signal through a non-uniform modulation filter. Signals with different sampling rates are serially output to the spread spectrum ratio adaptive variable burst capture unit 3 at a fixed 4 times sampling rate. The adaptive variable burst capture unit 3 first performs a preamble capture on the input signal and identifies the spread ratio, and then sends the spread ratio parameter, capture indication and signal to the adaptive demodulation synchronizer 4. The adaptive demodulation synchronizer 4 completes symbol synchronization and despreading of the input signal according to the spreading ratio, then completes carrier coarse synchronization and mode word recognition, completes modulation mode recognition and carrier synchronization according to the mode word, and then sends the demodulated data and parameters to the multi-mode decoder 5. The multi-mode decoder 5 identifies the encoding method and code rate according to the demodulation parameters, performs channel decoding on the input demodulated data to recover the information bit stream, and sends the information bit stream to the service frame reassembly processor 6; The service frame reassembly processor 6 searches, identifies, reassembles, and splices the segmented service frames carried by the physical layer according to the reassembly queue number, and outputs the result after performing a full frame CRC check.

[0005] The non-uniform channelization splitter 2 includes an input signal reconstruction module 2-1, an analysis and filtering module 2-2, a filter coefficient output control module 2-3, and a comprehensive filtering module 2-4; wherein, The signal reconstruction module 2-1 buffers the non-uniform multi-carrier digital baseband signal input to the improved CIC resampling filter 1, outputs it in a repetitive overlapping mode according to the number of sub-bands, and sends the buffered and reconstructed data to the analysis and filtering module 2-2 for fixed-length analysis filtering and IFFT transformation. The output is then sent to the comprehensive filtering module 2-4 for signal extraction at different rates. At the same time, the filter coefficient output control module 2-3 adjusts the reading step value of the comprehensive filter coefficients according to different rates (sampling rates) and synchronously sends the output coefficients to the comprehensive filtering module 2-4 to complete the comprehensive filtering. The multi-channel filtered signals are then processed by parallel-to-serial conversion, classified by rate level, and serially output to the spread spectrum ratio adaptive variable burst capture unit 3. The spread spectrum ratio adaptive variable burst capture device 3 includes an anti-frequency offset capture module 3-1, a spread spectrum ratio identification module 3-2, and an output control module 3-3; wherein, The frequency offset acquisition module 3-1 can acquire burst signals or locate frames of continuous signals, and can adapt to a maximum normalized Doppler frequency offset of ±1 / 8; the spreading ratio identification module 3-2 compares the correlation peak calculation results of the frequency offset acquisition module 3-1 and outputs the spreading ratio of the current signal; the output control module 3-3 performs buffer delay processing on the input signal, reads out the buffer signal according to the acquisition indication output by the frequency offset acquisition module 3-1, and sends it along with the spreading ratio and acquisition indication to the adaptive demodulation synchronizer 4; The adaptive demodulation synchronizer 4 includes a timing synchronization despreading module 4-1, a carrier coarse synchronization module 4-2, a pattern word recognition module 4-3, and a carrier tracking module 4-4; wherein, The timing synchronization and despreading module 4-1 uses a digital squared filtering timing algorithm to obtain the timing error through frequency domain phase rotation. Therefore, the squared timing error estimation algorithm is not sensitive to the signal amplitude and is suitable for various modulation methods such as MPSK, MAPSK, and MQAM. At the same time, it performs despreading processing on the timing-synchronized signal according to the spreading ratio parameter. The carrier coarse synchronization module 4-2 captures and corrects large frequency offsets through a binary search method. The pattern word recognition module 4-3 identifies the current modulation and coding method through RM decoding. The carrier tracking module 4-4 adopts an open-loop structure and completes carrier synchronization through the V&V algorithm.

[0006] The service frame reassembly processor 6 includes a reassembly information extraction module 6-1, a service frame search and reassembly module 6-2, and a service frame combining module 6-3; wherein, The reassembly information extraction module 6-1 performs CRC verification on the MAC frame header and extracts priority and reassembly queue information. Based on the priority and reassembly queue, it sends the data to different queue modules. The service frame search and reassembly module 6-2 completes the service frame search and reassembly function based on the reassembly queue number. The service frame combining module 6-3 performs combining processing on parallel multi-channel service frames and outputs the results.

[0007] Based on the reassembly queue number, the segmented service frames carried by the physical layer are searched, identified, reassembled, and spliced, and then output after performing full-frame CRC verification.

[0008] Compared with the prior art, the present invention has the following advantages: 1. This invention uses an improved CIC resampling filter to effectively reduce the resource consumption of onboard hardware while ensuring performance, and can meet the needs of low resource consumption of onboard equipment.

[0009] 2. The non-uniform channelization splitter in this invention can realize channelization processing of signals with multiple symbol rates, thereby meeting the communication needs of multiple rates and improving bandwidth utilization.

[0010] 3. The spread spectrum ratio adaptive variable burst capture device in this invention can adaptively complete the burst signal capture or continuous signal frame positioning processing of spread spectrum signals with a spread spectrum ratio of 1 to 8, and at the same time output the spread spectrum ratio parameter for subsequent demodulation processing.

[0011] 4. The adaptive demodulation synchronizer in this invention can adaptively identify the modulation and coding scheme of the input signal, complete symbol synchronization and carrier synchronization, and output demodulation parameters at the same time.

[0012] 5. The service frame reassembly processor in this invention can support parallel frame search and reassembly processing for up to 192 reassembly queues and supports priority queue management.

[0013] 6. This invention demodulates signals at multiple rates while outputting signals in a common frame format. The interface protocol is simple and highly scalable.

[0014] 7. This invention can be implemented using FPGA (Field Programmable FPGA) devices, and has the advantages of simple circuitry, small size, stable and reliable performance, making it suitable for engineering applications. Attached Figure Description

[0015] Figure 1 This is an electrical schematic diagram of a service-adaptive spaceborne non-uniform multi-carrier demodulation device in an embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A schematic diagram of a non-uniform channelization splitter.

[0017] Figure 3 yes Figure 1 A schematic diagram of an adaptive variable burst capture device with medium spread ratio.

[0018] Figure 4 yes Figure 1 A schematic diagram of an adaptive demodulation synchronizer.

[0019] Figure 5 yes Figure 1 A schematic diagram of a mid-service frame reassembly processor. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] Reference Figure 1 A service-adaptive onboard non-uniform multicarrier demodulation device includes an improved CIC resampling filter 1, a non-uniform channelization splitter 2, a spread ratio adaptive variable burst capture 3, an adaptive demodulation synchronizer 4, a multi-mode decoder 5, and a service frame reassembly processor 6. Figure 1 This is a schematic diagram of an embodiment of the present invention, which describes a service-adaptive onboard non-uniform multi-carrier demodulation device for broadband satellite processing payloads. The embodiment follows... Figure 1 Connecting lines.

[0022] The improved CIC resampling filter 1 performs orthogonal downconversion processing on the input digital intermediate frequency signal to obtain a digital baseband signal. It then performs resampling filtering on non-uniform multi-carrier digital baseband signals with different sampling rates and sends them to the non-uniform channelization splitter 2.

[0023] Non-uniform channelization splitter 2 processes the input non-uniform multicarrier digital baseband signal. (Refer to...) Figure 2The signal reconstruction module 2-1 buffers the resampled non-uniform multi-carrier digital baseband signal and outputs it in a repetitive overlapping mode according to the number of sub-bands. The buffered and reconstructed data is sent to the analysis and filtering module 2-2 for fixed-length analysis filtering and IFFT transformation, and then output to the comprehensive filtering module 2-4 for different rate signal extraction. At the same time, the filter coefficient output control module 2-3 adjusts the reading step value of the comprehensive filter coefficient according to different rates (sampling rates) and synchronously sends the output coefficients to the comprehensive filtering module 2-4 to complete the comprehensive filtering. The multi-channel filtered signals are then processed by parallel-to-serial conversion, classified by rate level, and output serially. Signals with different sampling rates are all serially output to the spread spectrum ratio adaptive variable burst capture unit 3 at a fixed 4 times sampling.

[0024] Reference Figure 3 The adaptive variable burst capture unit 3 includes a frequency offset capture module 3-1, a spread ratio identification module 3-2, and an output control module 3-3. The frequency offset capture module 3-1 uses normalization processing and differential correlation to capture high-dynamic burst signals or frame positioning of continuous signals, and can adapt to a maximum normalized Doppler frequency offset of ±1 / 8. The spread ratio identification module 3-2 compares the correlation peak calculation results of the frequency offset capture module 3-1 and outputs the spread ratio of the current signal. The output control module 3-3 performs buffer delay processing on the input signal, reads out the buffer signal according to the capture indication output by the frequency offset capture module 3-1, and sends it along with the spread ratio and capture indication to the adaptive demodulation synchronizer 4. Reference Figure 4 The adaptive demodulation synchronizer 4 includes a timing synchronization despreading module 4-1, a carrier coarse synchronization module 4-2, a pattern word recognition module 4-3, and a carrier tracking module 4-4. The timing synchronization despreading module 4-1 uses a digital squared filtering timing algorithm to obtain the timing error through frequency domain phase rotation. Therefore, the squared timing error estimation algorithm is insensitive to signal amplitude and is suitable for various modulation methods such as MPSK, MAPSK, and MQAM. Simultaneously, it despreads the timed synchronized signal according to the spreading ratio parameter. The carrier coarse synchronization module 4-2 captures and corrects large frequency offsets using a binary search method. The pattern word recognition module 4-3 identifies the current modulation and coding scheme through RM decoding. The carrier tracking module 4-4 adopts an open-loop structure and completes carrier synchronization using the V&V algorithm.

[0025] Reference Figure 5The service frame reassembly processor 6 includes a reassembly information extraction module 6-1, a service frame search and reassembly module 6-2, and a service frame combining module 6-3. The reassembly information extraction module 6-1 performs CRC verification on the MAC frame header and extracts priority and reassembly queue information, and sends the data to different queue modules according to the priority and reassembly queue. The service frame search and reassembly module 6-2 completes the service frame search and reassembly function according to the reassembly queue number. The service frame combining module 6-3 performs combining processing on parallel multi-channel service frames and outputs the results.

[0026] The basic working principle of this invention is as follows: The improved CIC resampling filter 1 performs quadrature down-conversion on the digital intermediate frequency signal sampled by the ADC to obtain a digital baseband signal. It then performs resampling filtering on non-uniform multi-carrier digital baseband signals with different sampling rates before sending them to the non-uniform channelization splitter 2. The non-uniform channelization splitter 2 processes the input non-uniform multi-carrier digital baseband signal, channelizing it through a non-uniform modulation filter. Signals with different sampling rates are serially output to the adaptive variable burst capture unit 3 at a fixed 4x sampling rate. The adaptive variable burst capture unit 3 first performs preamble capture on the input signal and identifies the spreading ratio, then sets the spreading ratio parameter and the capture value accordingly. Indicators and signals are sent to the adaptive demodulation synchronizer 4; the adaptive demodulation synchronizer 4 completes symbol synchronization and despreading of the input signal according to the spreading ratio, then completes carrier coarse synchronization and mode word identification, and completes modulation mode identification and carrier synchronization according to the mode word, and then sends the demodulated data and parameters to the multi-mode decoder 5; the multi-mode decoder 5 identifies the encoding mode and code rate according to the demodulation parameters, performs channel decoding on the input demodulated data to recover the information bit stream, and sends the information bit stream to the service frame reassembly processor 6; the service frame reassembly processor 6 searches, identifies and reassembles the segmented service frames carried by the physical layer according to the reassembly queue number, performs whole frame CRC check and outputs the result.

Claims

1. A service-adaptive non-uniform multicarrier demodulation device, comprising an improved CIC resampling filter (1) and a multi-mode decoder (5), characterized in that: It also includes a non-uniform channelization splitter (2), a spread ratio adaptive variable burst capture unit (3), an adaptive demodulation synchronizer (4), and a service frame reassembly processor (6). The improved CIC resampling filter (1) performs quadrature downconversion on the digital intermediate frequency signal sampled by the ADC to obtain a digital baseband signal, and performs resampling filtering on non-uniform multi-carrier digital baseband signals with different sampling rates, and sends them to the non-uniform channelization splitter (2); the non-uniform channelization splitter (2) processes the input non-uniform multi-carrier digital baseband signal, and performs channelization processing on the input signal through a non-uniform modulation filter. Signals with different sampling rates are all serially output to the spread spectrum ratio adaptive variable burst capture device (3) at a fixed 4 times sampling; the spread spectrum ratio adaptive variable burst capture device (3) first performs pre-capture on the input signal and identifies the spread spectrum ratio, and then sets the spread spectrum ratio parameter and the capture... Indication and signals are sent to the adaptive demodulation synchronizer (4); the adaptive demodulation synchronizer (4) first completes the symbol synchronization and despreading of the input signal according to the spreading ratio, then completes the carrier coarse synchronization and mode word recognition, completes the modulation mode recognition and carrier synchronization according to the mode word, and sends the demodulated data and parameters to the multi-mode decoder (5); the multi-mode decoder (5) performs channel decoding on the input demodulated data according to the demodulation parameters to recover the information bit stream, and sends the information bit stream to the service frame reassembly processor (6); the service frame reassembly processor (6) searches, identifies and reassembles the segmented service frames carried by the physical layer according to the reassembly queue number, performs whole frame CRC check and outputs the result.

2. The service-adaptive non-uniform multi-carrier demodulation device according to claim 1, characterized in that: The non-uniform channelization splitter (2) consists of a signal reconstruction module (2-1), an analysis and filtering module (2-2), a filter coefficient output control module (2-3), and a comprehensive filtering module (2-4); The signal reconstruction module (2-1) buffers the digital baseband signal sent by the improved CIC resampling filter (1), outputs it according to the number of subbands in the odd-even self-repeating overlapping mode, and sends the buffered and reconstructed data to the analysis and filtering module (2-2) for fixed-length analysis filtering and IFFT transformation, and forwards it to the comprehensive filtering module (2-4) for different rate signal extraction. At the same time, the filter coefficient output control module (2-3) adjusts the reading step value of the comprehensive filter coefficient according to different rates, and sends the output coefficient synchronously to the comprehensive filtering module (2-4) to complete the comprehensive filtering. The multi-channel filtered signal is processed by parallel-to-serial conversion, and after being classified by rate level, it is serially output to the spread spectrum ratio adaptive variable burst capture device (3).

3. The service-adaptive non-uniform multi-carrier demodulation device according to claim 1, characterized in that: The spread ratio adaptive variable burst capture unit (3) consists of an anti-frequency offset capture module (3-1), a spread ratio identification module (3-2), and an output control module (3-3); The frequency offset acquisition module (3-1) uses normalization processing and differential correlation to acquire high dynamic burst signals or frame localization of continuous signals, adapting to a maximum normalized Doppler frequency offset of ±1 / 8; the spread spectrum ratio identification module (3-2) compares the correlation peak calculation results of the frequency offset acquisition module (3-1) and outputs the spread spectrum ratio of the current signal; the output control module (3-3) performs buffer delay processing on the input signal, reads out the buffer signal according to the acquisition indication output by the frequency offset acquisition module (3-1), and sends it along with the spread spectrum ratio and acquisition indication to the adaptive demodulation synchronizer (4).

4. The service-adaptive non-uniform multi-carrier demodulation device according to claim 1, characterized in that: The adaptive demodulation synchronizer (4) includes a timing synchronization despreading module (4-1), a carrier coarse synchronization module (4-2), a pattern word recognition module (4-3), and a carrier tracking module (4-4). The timing synchronization despreading module (4-1) uses a digital squared filter timing algorithm to obtain the timing error through frequency domain phase rotation, and performs despreading processing on the timing-synchronized signal according to the spreading ratio parameter. The carrier coarse synchronization module (4-2) captures and corrects large frequency offsets through a binary search method. The pattern word recognition module (4-3) identifies the current modulation and coding scheme through RM decoding. The carrier tracking module (4-4) adopts an open-loop structure and completes carrier synchronization through the V&V algorithm.

5. The service-adaptive non-uniform multi-carrier demodulation device according to claim 1, characterized in that: The service frame reassembly processor (6) includes a reassembly information extraction module (6-1), a service frame search and reassembly module (6-2), and a service frame combining module (6-3). The reassembly information extraction module (6-1) performs CRC verification on the MAC frame header and extracts priority and reassembly queue information. Based on the priority and reassembly queue, it sends the data to different queue modules. The service frame search and reassembly module (6-2) completes the service frame search and reassembly function based on the reassembly queue number. The service frame combining module (6-3) performs combining processing on parallel multi-channel service frames and outputs the results.

Images