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WO2020134855A1 - 一种卫星通信系统 - Google Patents

一种卫星通信系统 Download PDF

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Publication number
WO2020134855A1
WO2020134855A1 PCT/CN2019/121951 CN2019121951W WO2020134855A1 WO 2020134855 A1 WO2020134855 A1 WO 2020134855A1 CN 2019121951 W CN2019121951 W CN 2019121951W WO 2020134855 A1 WO2020134855 A1 WO 2020134855A1
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WIPO (PCT)
Prior art keywords
signal
module
frequency
interference
modulation
Prior art date
Application number
PCT/CN2019/121951
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English (en)
French (fr)
Inventor
杨峰
任维佳
杜志贵
寇义民
Original Assignee
长沙天仪空间科技研究院有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority claimed from CN201811629492.5A external-priority patent/CN109698712B/zh
Priority claimed from CN201811629329.9A external-priority patent/CN109768823B/zh
Priority claimed from CN201910005961.4A external-priority patent/CN109802719B/zh
Application filed by 长沙天仪空间科技研究院有限公司 filed Critical 长沙天仪空间科技研究院有限公司
Priority to CN201980086573.1A priority Critical patent/CN113454919B/zh
Publication of WO2020134855A1 publication Critical patent/WO2020134855A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/71—Interference-related aspects the interference being narrowband interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks

Definitions

  • the invention belongs to the technical field of wireless communication, and particularly relates to a satellite channel system.
  • OFDM Orthogonal Frequency Division Multiplexing
  • OFDM technology uses a discontinuous multi-tone modulation technology to combine a large number of signals in carriers of different frequencies into a single signal to complete signal transmission.
  • the development of OFDM technology is to improve the spectrum utilization rate of the carrier. Its characteristic is that each subcarrier is orthogonal to each other, so the spectrum after spread spectrum modulation can overlap each other, thus reducing the mutual interference between the subcarriers.
  • WiMAX communication system is a communication system based on OFDM modulation technology.
  • One of the important keys to using OFDM is to increase the ability to resist frequency selective fading, while also increasing the ability to resist narrowband interference.
  • the condition that the OFDM system can resist narrow-band interference is assuming that the power of the OFDM signal is much larger than that of the narrow-band interference; however, in practical applications, the transmission power of the OFDM signal is limited, so that when the external narrow-band interference signal is strong enough Normal demodulation performance will be deteriorated. Therefore, how to suppress narrow-band interference in limited spectrum resources is a problem that cannot be ignored.
  • Narrow-band strong interference is a common interference in practical applications, and its suppression can be done in the time domain or the frequency domain.
  • the time-domain method uses the correlation of narrow-band interference to perform adaptive filtering using the least mean square algorithm or the recursive least square algorithm.
  • the frequency domain method uses fast Fourier transform or inverse fast Fourier transform to zero the frequency of interference to eliminate interference.
  • the common frequency domain filtering mainly has the following two methods: The first method is a simple interference suppression technology based on FFT/IFFT, which outputs the data through windowing, FFT calculation, NBI filter processing and IFFT calculation, In the second way, in order to reduce the signal-to-noise ratio loss caused by windowing, an interference suppression technique based on superimposed fast Fourier transform is proposed.
  • the basic idea is to copy and shift the input data into windowing, get two windowed data together with the original windowed data, perform FFT transformation, and perform filtering in the frequency domain. After filtering, perform IFFT to obtain interference-free time-domain data. Align and merge the two data to get the final output.
  • the patent document with publication number CN105549035B discloses a device and method for detecting and eliminating narrowband interference in the frequency domain of a baseband signal.
  • the method includes: dividing an intermediate frequency signal into two channels, which are respectively output to a narrowband interference detector and a narrowband interference canceller.
  • the narrow-band interference detector performs interference detection on a received intermediate frequency signal to obtain interference detection information, and sends it to the narrow-band interference canceller, and the narrow-band interference canceller performs an operation on another received intermediate frequency according to the interference detection information.
  • the signal is processed for narrow-band interference cancellation.
  • the invention multiplies the time domain of the signal by a window function to perform windowing before performing the fast Fourier transform.
  • the multiplication in the time domain is equivalent to the convolution in the frequency domain, so the effect of windowing is only to reduce interference Sidelobes produced by the source.
  • the performance that windowing can improve depends on the frequency of the interference source. When the interference source is not located on a certain subcarrier frequency, spectrum leakage will occur, and narrowband interference will affect all adjacent subcarriers. And it does not consider the elimination of inter-carrier interference.
  • module as used herein describes any type of hardware, software, or combination of hardware and software that is capable of performing the function associated with the “module.”
  • the present invention provides a satellite communication system, especially a narrow-band multi-channel satellite communication system.
  • the signal can be transmitted to at least one narrow-band satellite via a ground station, and several ground stations can be based on each other Narrowband satellite relays are communicatively coupled.
  • the ground station includes at least an encoding module and a first modulation module.
  • the ground station is configured to modulate the signal as follows:
  • the encoding module is configured to The signal performs an encoding process to obtain an encoded signal;
  • the first modulation module is configured to perform a serial-to-parallel conversion process on the encoded signal to generate a first branch code stream and a second branch code stream, where: in the first When the branch code stream performs delay processing so that the first branch code stream and the second branch code stream are spaced apart from each other by a set symbol period, the first branch code stream sequentially performs the first The first-stage filtering process and the first-stage modulation process obtain the first modulation signal, and the second branch code stream performs the first-stage filtering process and the second-stage modulation process in sequence to obtain the second modulation signal; the first modulation The signal and the second modulation signal are jointly subjected to the second-stage modulation process to obtain a third modulation signal, wherein the third modulation signal is subjected to the second-stage filter process to complete the modulation process.
  • the first-stage filtering process is performed by a raised cosine roll-off filter
  • the second-stage filtering process is performed by a band-pass filter.
  • the signal spectrum will have a periodic extension phenomenon, which eventually generates inter-symbol interference, and there will be side-lobe interference within the frequency range of the modulated signal, which reduces the modulated signal.
  • the quality of the code increases the bit error rate.
  • the second-stage filtering process can reduce the size of side lobes in the frequency range to the specified decibel range, and can eliminate inter-symbol interference.
  • the third modulation signal generated by modulation has a lower average power ratio peak value than the prior art. And through the first-stage filtering process, any phase discontinuities of the first branch code stream and the second branch code stream can be effectively removed smoothly.
  • the encoding module is configured to perform encoding processing on the signal in the following manner: the BCH code generated by the signal through the BCH encoding process and the transmitted information frame together constitute several information subframes with set bits, the The information subframes are subjected to synchronous scrambling to sequentially perform RS encoding and convolutional encoding.
  • the convolutionally encoded data and the carrier synchronization bits, pilot sequence, unique code, and frame tail together form a complete modulated data frame, in which: When the bit length of the information subframe is less than the set bit length, it is complemented in a manner of supplementing zero codes.
  • the ground station further includes a filtering module, a second modulation module and a frequency conversion module, and the ground station further processes the signal in the following manner: the encoded signal is transmitted to the first modulation module at a set code rate After the modulation process is performed in, the first carrier frequency is transmitted to the filter module; the filter module is configured to perform a filter process on the signal it receives and transmit it to the second modulation module; the second modulation module uses the second The carrier frequency transmits the signal it receives to the frequency conversion module, wherein the frequency conversion module is configured to frequency convert the signal it receives to a set radio frequency output frequency.
  • the narrowband satellite includes at least a signal conditioning module and an interference cancellation module, and in the case where the signal is transmitted to the narrowband satellite via the ground station, the narrowband satellite is configured to perform on the signal as follows Processing:
  • the signal conditioning module is configured to: determine the frequency component of the signal and acquire several decomposed signals in different time-frequency spaces to separate the frequency content of the interference signal.
  • the interference cancellation module is configured to: align the frequency of the interference signal with the center of the subcarrier frequency of the communication channel and establish a first complex sinusoid, and obtain based on the multiplication processing of the first complex sinusoid and the signal to obtain Offset signals and introduce inter-carrier interference therefrom; sequentially performing windowing processing and fast Fourier transform processing on the offset signals to generate a frequency domain signal, which can eliminate the frequency by setting the subcarrier frequency to zero Interference signal to obtain an interference cancellation signal; in the case where the interference cancellation signal is processed by inverse fast Fourier transform to generate time-domain sampling samples, a second complex sine curve is established and according to the second complex sine curve and the time domain The sampling samples perform multiplication processing to eliminate the inter-carrier interference.
  • the signal conditioning module obtains the decomposed signal as follows: configure a filter bank with several different filtering levels, and each filtering level includes at least a low communication channel and a high communication channel, the low communication channel and Each of the high communication channels is configured with at least one set of discrete wavelet transformers, wherein: based on several filter levels of the filter bank, several subbands of different frequency bands will be acquired; The discrete wavelet transform process decomposes into several different time-frequency spaces.
  • the first complex sine curve is given by the formula Limited
  • the second complex sine curve is given by the formula Limited
  • the scrambling code period and polynomial of the synchronous scrambling process are 2 15 -1 and 1+X 14 +X 15 respectively ; where F s represents the sampling frequency and N is the number of fast Fourier transform sampling points .
  • the first-stage filtering process is performed by a first filter
  • the second-stage filtering process is performed by a second filter
  • the first filter is a raised cosine roll-off filter
  • the first The second filter is a band-pass filter
  • the first-stage modulation process is a quadrature modulation process
  • the second-stage modulation process is an in-phase modulation process.
  • the narrowband satellite further includes an interference detection module and a demodulation module
  • the interference detection module is configured to calculate an average power of the signal to determine whether there is an interference signal in the subband
  • the demodulation module is configured to interfere with the interference
  • the output signal of the elimination module is demodulated.
  • the interference cancellation module is further configured to obtain the frequency ⁇ f of the fast Fourier transform filter bank closest to the frequency of the interference signal, wherein: the frequency of the first complex sinusoid is ⁇ f, and the second complex The frequency of the sine curve is - ⁇ f.
  • the interference cancellation module can set the frequency of the fast Fourier transform filter bank corresponding to the subcarrier frequency to zero to set the frequency The interference signal is eliminated.
  • the present invention also provides a satellite communication system, especially a narrow-band satellite communication system, at least including a narrow-band satellite and a ground station, the narrow-band satellite is configured to at least suppress interference of the signal during signal relay Processing to realize the transmission of the signal between several ground stations, which converts the signal it receives to several different RF output frequencies to establish multi-channel transmission with the narrow-band satellites ,
  • the narrow-band satellite is configured to: respectively establish a first complex sinusoid and a second complex sinusoid, and determine the frequency component of the signal to separate the frequency content of the interference signal; based on the first complex sinusoid and
  • the first-stage multiplication processing of the signal acquires the first processed signal and introduces inter-carrier interference; eliminates the interference signal in a manner that the subcarrier frequency is set to zero to obtain the second processed signal; after the second processed signal is subjected to Fast Fourier In the case of inverse transform processing, the second-stage multiplication processing based on the second complex sinusoid and the second processed signal
  • the narrow-band satellite is further configured to: align the frequency of the interference signal with the frequency of the sub-carrier frequency of the communication channel; obtain the frequency ⁇ f of the fast Fourier transform filter bank closest to the frequency of the interference signal; The interference signal is eliminated by setting the frequency ⁇ f of the fast Fourier transform filter bank corresponding to the subcarrier frequency to zero.
  • the narrowband satellite is further configured to configure a filter bank with several different filtering levels, and each filtering level includes at least a low communication channel and a high communication channel, the low communication channel and the high communication channel
  • each filtering level includes at least a low communication channel and a high communication channel, the low communication channel and the high communication channel
  • Each is configured with at least one set of discrete wavelet transformers, wherein: several subbands of different frequency bands are obtained based on several filter levels of the filter bank; the signals contained in the subbands can be decomposed into several by discrete wavelet transform processing, respectively Different time-frequency space to separate the frequency content of the interference signal.
  • the ground station includes at least an encoding module, a first modulation module and a filtering module, the ground station is configured to process the signal it receives in the following manner: the encoding module performs at least BCH encoding processing, RS The encoding process and the convolutional encoding process perform a common processing on the signal to encode the signal to obtain an encoded signal; the first modulation module performs modulation processing on the encoded signal and transmits it to the filter module at a first carrier frequency, wherein : When acquiring the first tributary code stream and the second tributary code stream with a symbol period set apart from each other based on the encoded signal, at least based on the first tributary code stream and the second tributary code stream The tributary code stream obtains the first modulation signal and the second modulation signal respectively; the first modulation signal and the second modulation signal acquire the third satisfying the first carrier frequency in a manner of sequentially performing modulation processing and filtering processing Modulated signal.
  • the encoded signal acquires the first branch code stream and the second branch code stream in a manner of performing serial-parallel conversion processing, the first branch code stream or the second branch code
  • the streams can be set at intervals from each other in a manner to perform delay processing, wherein: in the case where the first branch code stream performs the delay processing, the first branch code stream performs the first
  • the first modulation signal is acquired in the manner of first-level filtering and second-stage modulation
  • the second branch code stream is acquired in the manner of sequentially performing the first-stage filtering and second-stage modulation A modulation signal
  • the first modulation signal and the second modulation signal acquire the third modulation signal in a manner of sequentially performing a second-stage modulation process and a second-stage filter process.
  • the first-stage filtering process is performed by a raised cosine roll-off filter
  • the second-stage filtering process is performed by a band-pass filter.
  • the signal spectrum will have a periodic extension phenomenon, which will eventually produce inter-symbol interference, and there will be side-lobe interference within the frequency range of the modulated signal, which reduces the modulated signal.
  • the quality of the code increases the bit error rate.
  • the second-stage filtering process can reduce the size of side lobes in the frequency range to the specified decibel range, and can eliminate inter-symbol interference.
  • the third modulation signal generated by modulation has a lower average power ratio peak value than the prior art. And through the first-stage filtering process, any phase discontinuities of the first branch code stream and the second branch code stream can be effectively removed smoothly.
  • the encoding process includes at least the following steps: the signal is subjected to the BCH encoding process to generate a BCH code, and the BCH code and the transmitted information frame together constitute a number of information subframes with set bits in the manner of supplementary zero codes;
  • the information subframe is sequentially subjected to synchronous scrambling processing, RS coding processing and convolutional coding processing to obtain processed data
  • the processed data is at least complete with the carrier synchronization bit, pilot sequence, unique code and frame tail Modulation data frame.
  • the ground station further includes a second modulation module and a frequency conversion module
  • the filter module includes at least a first filter and a second filter, wherein: the filter module controls the first One branch code stream and the second branch code stream perform the first-stage filtering process and the second filter performs the second-stage filtering process on the third modulated signal in a manner The signal is filtered; in the case where the third modulated signal is transmitted to the second modulation module through the filter module, the second modulation module transmits the signal it receives to the frequency conversion at the second carrier frequency Module; the frequency conversion module converts the signal it receives to a set radio frequency output frequency.
  • the present invention provides a satellite communication system based on suppression of narrow-band interference.
  • the narrow-band satellite and the ground station communicate with each other in a multi-channel manner to relay transmission of a combined signal having several constituent signals.
  • the narrowband satellite is configured to:
  • the second-stage multiplication processing based on the second complex sinusoid and the second processed signal eliminates the inter-carrier interference
  • the narrow-band satellite includes at least an interference detection module, a windowing module, a separation module and a regeneration module.
  • the narrow-band satellite is configured to Combined signal processing: the windowing module is configured to generate a window processing signal after limiting the frequency of the combined signal based on windowing processing; the interference detection module is configured to perform n-th power processing based on the window processing signal to Determining the modulation characteristic of at least one component signal and the symbol rate of its corresponding carrier; the separation module is configured to be based on the symbol rate when the window processed signal generates at least one continuous wave based on the nth power processing Resample the window processing signal by m times to generate a resampled signal, and use this to determine at least one symbol trajectory and at least one modulation type; the regeneration module is configured to pair based on the symbol trajectory and the modulation type The component signals are synthesized and reproduced to generate a synthesized signal.
  • the narrow-band satellite further includes a cancellation module and an inversion module, and in the case where the synthesized signal is determined to be an interference signal, the narrow-band satellite is configured to process the synthesized signal as follows:
  • the conversion module is configured to invert the synthesized signal to generate an inverted copy;
  • the cancellation module is configured to receive a copy of the combined signal and superimpose the inverted copy and the combined signal to Generate the first-level interference suppression signal.
  • the narrowband satellite further includes a signal preprocessing module and an interference cancellation module, the narrowband satellite is configured to process the first-level interference suppression signal in the following manner: the signal preprocessing module is configured to establish a A complex sinusoidal curve and a second complex sinusoidal curve, and determining the frequency component of the first-stage interference suppression signal to separate the frequency content of the interference signal.
  • the interference cancellation module is configured to: introduce inter-carrier interference in a manner of performing multiplication processing of the first interference suppression signal and the first complex sinusoidal curve to generate an offset signal; and obtain interference in a manner of setting a subcarrier frequency to zero Eliminating the signal and acquiring its time-domain sampling samples; eliminating the inter-carrier interference in a manner that the time-domain sampling samples and the second complex sinusoidal curve perform multiplication processing.
  • the interference cancellation module acquires the interference cancellation signal as follows: aligns the frequency of the interference signal with the frequency of the subcarrier frequency of the communication channel and acquires the fast Fourier transform filter closest to the frequency of the interference signal The frequency ⁇ f of the group; performing the windowing process and the fast Fourier transform process on the offset signal in sequence to generate a frequency domain signal; and setting the frequency ⁇ f of the fast Fourier transform filter bank corresponding to the subcarrier frequency to zero.
  • the signal preprocessing module is configured to configure a filter bank with several different filtering levels, and each filtering level includes at least a low communication channel and a high communication channel, the low communication channel and the high communication channel
  • Each channel is configured with at least one set of discrete wavelet transformers, wherein: based on several filter levels of the filter bank, several subbands of different frequency bands are obtained; signals contained in the subbands can be decomposed into discrete wavelet transforms to Several different time-frequency spaces.
  • the ground station includes at least an encoding module and a first modulation module, the ground station is configured to modulate the signal as follows: the encoding module is configured to perform encoding processing on the signal to obtain Coded signal; the first modulation module is configured to perform a serial-to-parallel conversion process on the coded signal to generate a first branch code stream and a second branch code stream, wherein: performing delay on the first branch code stream Processing such that when the first branch code stream and the second branch code stream are separated from each other by a set symbol period, the first branch code stream sequentially performs the first-stage filtering process and the first The first-level modulation process obtains a first modulation signal, and the second branch code stream sequentially performs the first-level filter process and the second-stage modulation process to obtain a second modulation signal; the first modulation signal and the second The modulated signals are collectively subjected to the second-stage modulation process to obtain a third modulated signal, wherein the third-modulated signal is subjected to the second-
  • the first-stage filtering process is performed by a raised cosine roll-off filter
  • the second-stage filtering process is performed by a band-pass filter.
  • the signal spectrum will have a periodic extension phenomenon, which will eventually produce inter-symbol interference, and there will be side-lobe interference within the frequency range of the modulated signal, which reduces the modulated signal.
  • the quality of the code increases the bit error rate.
  • the second-stage filtering process can reduce the size of side lobes in the frequency range to the specified decibel range, and can eliminate inter-symbol interference.
  • the third modulation signal generated by modulation has a lower average power ratio peak value than the prior art. And through the first-stage filtering process, any phase discontinuities of the first branch code stream and the second branch code stream can be effectively removed smoothly.
  • the encoding process includes at least the following steps: the signal undergoes BCH encoding processing to generate a BCH code, and the BCH code and the transmitted information frame together constitute a number of information subframes with set bits in a manner of supplementing zero codes;
  • the processed data at least together with the carrier synchronization bit, pilot sequence, unique code, and frame tail form a complete modulation Data Frame.
  • the ground station further includes a filtering module, a second modulation module and a frequency conversion module, and the ground station further processes the signal in the following manner: the encoded signal is transmitted to the first modulation module at a set code rate After the modulation process is performed in, the first carrier frequency is transmitted to the filter module; the filter module is configured to perform a filter process on the signal it receives and transmit it to the second modulation module; the second modulation module uses the second The carrier frequency transmits the signal it receives to the frequency conversion module, wherein the frequency conversion module is configured to frequency convert the signal it receives to a set radio frequency output frequency.
  • the narrowband satellite further includes a demodulation module
  • the interference detection module is configured to calculate the average power of the signal to determine whether there is an interference signal in the subband
  • the demodulation module is configured to output the interference cancellation module The signal is demodulated, where the frequency of the first complex sinusoid is ⁇ f and the frequency of the second complex sinusoid is - ⁇ f.
  • the filtering module performs the first-stage filtering process on the first branch code stream and the second branch code stream according to a first filter and a second filter on the third modulated signal Performing the second-stage filtering process by filtering the received signal; in the case where the third modulated signal is transmitted to the second modulation module through the filtering module, the second modulation module
  • the second carrier frequency transmits the signal it receives to the frequency conversion module;
  • the first filter is a raised cosine roll-off filter, the second filter is a band-pass filter;
  • the first-stage modulation processing is In quadrature modulation processing, the second-stage modulation processing is in-phase modulation processing.
  • each narrow-band interference signal when each narrow-band interference signal is aligned with the center of the sub-carrier frequency of the communication channel, it will cause inter-carrier interference.
  • the signal will no longer carry the narrow-band interference after the sub-carrier frequency aligned with the narrow-band interference is removed, and then the inter-carrier interference is removed from the signal. Therefore, before decoding, the signal removes all narrow-band interference and any potential side lobes, thereby eliminating spectral leakage.
  • the digital shaping filter of the present invention can eliminate inter-symbol interference, and thus can meet the Nyquist characteristic without inter-symbol interference, and can also smooth the waveform, and thus can accelerate the out-of-band attenuation speed of the modulated signal and improve the spectrum utilization rate.
  • the processing of the band-pass filter can make the modulation envelope smoother.
  • the present invention can receive signals with overlapping frequencies, detect and filter the interference signals contained therein, and can effectively improve the utilization rate of spectrum resources.
  • FIG. 1 is a schematic diagram of the modular connection relationship of the preferred narrowband multi-channel satellite communication system of the present invention
  • FIG. 2 is a schematic diagram of the modular structure of the preferred ground station of the present invention.
  • FIG. 3 is a schematic diagram of the modulation processing flow of the first modulation module preferred in the present invention.
  • FIG. 4 is a schematic diagram of the modular structure of the preferred narrowband satellite of the present invention.
  • FIG. 5 is a schematic diagram of the processing flow of the preferred interference cancellation module of the present invention.
  • FIG. 6 is a block diagram of a preferred RS code encoding of the present invention.
  • FIG. 7 is a coding block diagram of a preferred convolutional code of the present invention.
  • FIG. 8 is a schematic diagram of the processing flow of the preferred encoding module of the present invention.
  • FIG. 9 is a schematic diagram of a modular structure of another narrow-band satellite preferred by the present invention.
  • FIG. 10 is a schematic diagram of the processing flow of the combined signal of the narrowband satellite of the present invention. .
  • Narrow-band satellites 2 Ground station
  • interference detection module 101 interference detection module 102: interference cancellation module 103: demodulation module
  • signal conditioning module 105 analog-to-digital conversion module
  • 106 windowing module
  • coding module 202 first modulation module 203: filter module
  • first filter 203b second filter
  • first modulator 202b second modulator 202c: third modulator
  • Each "module” in the present invention may be one or more of a dedicated integrated chip, a server, and a server group.
  • the module of the present invention describes any kind of hardware, software, or combination of hardware and software that can perform the function associated with the “module”.
  • the present invention provides a multi-channel satellite communication system, which includes at least one narrow-band satellite 1 and several ground stations 2 that communicate with each other.
  • the multi-channel satellite communication system includes a narrow-band satellite 1, a first ground station 2a, and a second ground station 2b.
  • the first ground station 2a may send the data signal it receives to the narrowband satellite 1, and then relay it to the second ground station 2b through the narrowband satellite 1.
  • the second ground station 2b may also relay the data signal it receives to the first ground station 2a through the narrowband satellite 1.
  • the first ground station 2a and the second ground station 2b may individually have their respective gateways, and all the gateways may be communicatively coupled to each other through a common network.
  • the ground station 2 includes at least an encoding module 201, a first modulation module 202, a filtering module 203, a second modulation module 204, and a frequency conversion module 205.
  • the encoding module 201 is used to encode the original data information received by the ground station 2 and transmit the encoded digital signal to the first modulation module 202 according to the set code rate.
  • the first modulation module 202 is used to modulate the digital signal to be converted to the set first carrier frequency.
  • the digital signal modulated by the first modulation module 202 is transmitted to the filtering module 203 for filtering.
  • the digital signal filtered by the encoding module 201 of the filtering module 203 is transmitted to the second modulation module 204 for re-modulation to switch to the set second carrier frequency.
  • the digital signal with the second carrier frequency is transmitted to the frequency conversion module 205.
  • the frequency conversion module 205 is used to convert the digital signal processed by the second modulation module 204 to a set transmission frequency point so as to upload it to the narrowband satellite 1.
  • the encoding module 201 may be configured to encode the original data information based on cyclic encoding or convolutional encoding.
  • the first modulation module 202 and the second modulation module 204 may be based on one of digital phase modulation, multi-ary digital phase modulation, phase shift keying modulation, quadrature phase keying modulation, offset quadrature phase shift keying modulation Or a combination of multiple types to modulate the digital signal.
  • the filtering module 203 can be a digital shaping filter.
  • the digital shaping filter can eliminate inter-symbol interference, which can meet the Nyquist characteristic without inter-symbol interference, and can also smooth the waveform, which can accelerate the out-of-band attenuation speed of the modulated signal. To improve spectrum utilization.
  • the frequency conversion module 205 may be a programmable phase-locked loop chip.
  • the modulation signal can be converted to a set RF output frequency range, and then the frequency division interval can be set by setting Divide the available spectrum at equal frequency intervals into several carrier channels. Dividing the spectrum into multiple channels can improve the spectrum utilization. For example, if the available frequency band is 100.0000MHz to 100.0100MHz, and if the frequency division interval is 100Hz, the frequency band can be divided into 100 channels.
  • the narrowband signal can be obtained through the frequency conversion module. Furthermore, narrow-band multi-channel communication between the ground station 2 and the narrow-band satellite 1 is realized.
  • the ground station 2 may send the original data to the first modulation module 202 at a code rate of 600 bps after being encoded by the encoding module for modulation processing.
  • the first modulation module 202 transmits to the filter module 203 with a carrier frequency of 15 KHz to perform filter processing.
  • the second modulation module 204 remodulates the 15 KHz modulation signal so that it is transmitted to the frequency conversion module 205 at a carrier frequency of 10.685 MHz.
  • the first modulation module 202 is further configured to modulate the encoded signal processed by the encoding module 201 according to the following working mode:
  • S1 The coded signal undergoes serial-parallel conversion processing to generate a first branch code stream and a second branch code stream, where the first branch code stream and the second branch code stream are spaced apart from each other by setting codes Metacycle.
  • the respective code rates of the first tributary code stream and the second tributary code stream are two One in one.
  • the first tributary code stream can be transmitted in a serial transmission manner
  • the second tributary code stream can be transmitted in a parallel transmission manner.
  • the set symbol period may be a half symbol period. Either the first branch code stream or the second branch code stream can be shifted by half a symbol period after being delayed by half a symbol period. cycle.
  • the first filter 203a is a digital shaping filter.
  • the digital shaping filter may be a raised cosine roll-off filter. By controlling the roll-off coefficient, the shaped waveform of the encoded signal can be changed, thereby reducing the influence of sampling timing errors.
  • the frequency response H(f) of the raised cosine roll-off filter can be expressed by the following formula:
  • the corresponding time-domain waveform function is:
  • the symbol period T s 1/2f N , where f N is the Quinnest frequency.
  • ⁇ is the roll-off factor, which determines the shape of H(f), and ⁇ takes a value between [0, 1].
  • ⁇ is large, the time-domain waveform attenuation block and the oscillation fluctuation are small, which is beneficial to reduce the impact of inter-symbol interference and timing error, but the occupied frequency band becomes wider, the frequency band utilization rate is reduced, and the effect of in-band noise on the signal Will increase accordingly.
  • the roll-off factor ⁇ can be selected as 0.5, and the order of the digital shaping filter is set to 32.
  • the first modulation module 202 includes at least a first modulator 202a, a second modulator 202b, and a third modulator 202c.
  • the first modulator 202a is a quadrature modulator
  • the second modulator 202b and the third modulator 202c are both in-phase modulators.
  • the first branch code stream is transmitted to the first modulator 202a for orthogonal modulation processing to obtain a first modulated signal
  • the second branch code stream is transmitted to a second modulator for in-phase modulation processing to obtain a second modulated signal.
  • Both the first modulation signal and the second modulation signal are uniformly transmitted to the third modulator 202c for in-phase modulation processing to obtain a third modulation signal.
  • the first-stage modulation process can be performed by the first modulator 202a. By the second modulation its 202b and the third modulator 202c can perform a second-stage modulation process.
  • the third modulated signal is transmitted to the second filter 203b for filtering processing to complete the modulation processing of the encoded signal.
  • the second filter 203b is a band-pass filter that allows signals within a specific frequency range to pass, and can attenuate signals outside the specific frequency range to a very low level.
  • the coded signal is based on the modulation re-sampling process of the modulation module, which causes periodic extension of the signal spectrum and generates inter-symbol interference, which in turn leads to an increase in the error probability of the modulation module.
  • the order of the band-pass filter can be set to 64.
  • the processing of the band-pass filter can make the modulation envelope smoother.
  • the second-stage filtering process can be performed by the second filter 203b.
  • the first ground station 2a may send the first signal to the narrowband satellite 1, and then relay the first signal to the second ground station 2b through the narrowband satellite 1.
  • the second ground station 2b transmits the second signal to the narrow-band satellite
  • the second ground station 2b can simultaneously receive the echo of the second signal and the first signal as a combined signal.
  • the first ground station 2a can simultaneously receive the echo of the first signal and the second signal as a combined signal.
  • the first ground station 2a and the second ground station 2b can use the echo cancellation method to eliminate the interference caused by the echo. By canceling the echo, the demodulation of the first signal and the second signal can be facilitated.
  • the first signal and the second signal are subject to different environments and different degrees of interference during transmission, resulting in the combined signal received by the ground station requiring at least the transmitted signal, the echo of the transmitted signal, and the noise floor.
  • the transmission signal that needs to be transmitted refers to the first signal or the second signal that needs to be transmitted between the first ground station and the second ground station.
  • the noise floor refers to the sum of all noise sources and unwanted signals in the communication system, that is, any other signal except the transmitted signal.
  • the narrow-band satellite 1 includes at least a signal conditioning module 104.
  • the signal conditioning module 104 includes several filters to resolve, analyze, or suppress interfering signals on the combined signal.
  • the signal conditioning module 104 is configured to process the combined signal as follows:
  • the signal conditioning module 104 may include a fast Fourier transformer, and transmitting the combined signal to the fast Fourier transformer can implement the fast Fourier transform of the combined signal.
  • the fast Fourier transformer can add the product of the combined signal samples and the complex sinusoid of the frequency to obtain the frequency domain representation of the combined signal, where the processing process of the fast Fourier transformer can be expressed as: x n is the digital sample of the combined signal. N is the total number of samples being processed.
  • the output signal processed by the fast Fourier transform is decomposed to obtain multiple decomposed signals in different time-frequency spaces.
  • the output signal may be transmitted into the filter bank, and the filter bank may include several different filtering levels.
  • Each filtering level may include a low communication channel and a high communication channel, and the low communication channel and the high communication channel are each configured with a set of discrete wavelet transformers.
  • the output signal can be divided into subbands of different frequency bands.
  • the signals contained in different subbands can be decomposed into multiple different time-frequency spaces by the discrete wavelet transform processing of the discrete wavelet transformer.
  • the time-frequency content of the transmitted signal is separated from the frequency content of the interference signal.
  • the narrow-band satellite 1 includes at least an interference detection module 101, an interference cancellation module 102, and a demodulation module 103.
  • the narrowband satellite 1 may have a signal receiving module such as an antenna, and thus can receive signals transmitted by the ground station 2 or other signal terminals.
  • the interference detection module 101 is used to perform interference detection on signals in several different sub-bands output by the signal conditioning module 104, and thus can determine frequencies corresponding to all interference sources present in the combined signal.
  • the interference cancellation module 102 is configured to perform, for example, filtering processing on the interference source detected and determined by the interference detection module, so as to achieve interference cancellation.
  • the demodulation module 103 is used to demodulate the signal to facilitate further transmission of the signal.
  • the interference detection module 101 can calculate the average power of the combined signal and set a standard threshold.
  • the interference detection module analyzes and determines that the actual power of the combined signal is higher than the set standard threshold, it can be determined that there is interference.
  • the set value of the standard threshold can be determined in advance through the simulation of the interference signal in advance.
  • the interference cancellation module 102 may include an offset logic circuit 102a, a first multiplier 102b, a window function circuit 102c, a first fast Fourier transform circuit 102d, an interference cancellation circuit 102e, an inverse fast Fourier transform circuit 102f and signal correction circuit 102g.
  • the offset logic circuit 102a is used to align the frequency of the interference signal with the frequency center of the subcarrier of the communication channel.
  • the offset logic circuit can determine the frequency between the interference signal and the center frequency of the fast Fourier transform filter bank frequency ⁇ f The difference and the offset logic circuit can determine one or more of the frequency of the fast Fourier transform filter bank that is closest to the frequency of the interference signal.
  • the offset logic circuit can also create a first complex sinusoidal curve with respect to the received signal for performing multiplication of the analog signals with each other in the first multiplier 102b.
  • F s represents the sampling frequency.
  • N is the number of fast Fourier transform sampling points.
  • the first multiplier 102b may receive the first complex sinusoid and the combined signal from the offset logic circuit, where the combined signal contains sampled samples of the interference signal.
  • the first multiplier 102b multiplies the first complex sinusoid by the sampled sample to obtain the offset signal.
  • inter-carrier interference can also be introduced into the first multiplier 102b by multiplying the first complex sinusoid by the sampled samples.
  • the window function circuit 102c is used to receive the output of the first multiplier 102b and perform windowing processing on it.
  • the window function circuit may use, for example, a Hanning window function, a rectangular window function, or a Bartley window function to window the signal.
  • the first fast Fourier transform circuit 102d can receive the output of the window function circuit 102c and perform fast Fourier transform processing on it to generate a frequency domain signal.
  • the interference cancellation circuit 102e can receive the demodulated fast Fourier transform signal processed by the first fast Fourier transform circuit 102d, and the interference cancellation circuit 102e can use the offset logic circuit 102a in the fast Fourier transform signal during the calculation of ⁇ f
  • the determined subcarrier frequency is removed to obtain an interference cancellation signal.
  • the interference cancellation circuit 102e can set the frequency of the fast Fourier transform filter bank corresponding to the subcarrier frequency to zero. Since the frequency of the interference signal has been processed by the offset logic circuit 102a to be aligned with the frequency center of the subcarrier, and the frequency of the current subcarrier is set to zero by the interference cancellation circuit 102e, the interference signal is eliminated.
  • the interference cancellation signal can be transmitted to the inverse fast Fourier transform circuit 102f and is subjected to inverse fast Fourier transform processing to generate time-domain sampling samples.
  • the second complex sine curve generated by the correction circuit 102g and the output signal generated by the inverse fast Fourier transform circuit 102f are simultaneously transmitted to the second multiplier 102h for multiplication processing to eliminate inter-carrier interference.
  • the output signal of the second multiplier 102h can be transmitted to the second fast Fourier transform circuit 102i to perform fast Fourier transform processing again to demodulate the signal.
  • the output signal of the second fast Fourier transform circuit 102i is finally transmitted to the demodulation module 103 for decoding processing.
  • the first fast Fourier transform circuit 102d and the second fast Fourier transform circuit 102i jointly define a fast Fourier transform filter bank.
  • each narrow-band interference signal when each narrow-band interference signal is aligned with the frequency center of the sub-carrier of the communication channel, it will cause inter-carrier interference.
  • the signal will no longer carry the narrow-band interference after the sub-carrier frequency aligned with the narrow-band interference is removed, and then the inter-carrier interference is removed from the signal. Therefore, before decoding, the signal removes all narrow-band interference and any potential side lobes, thereby eliminating spectral leakage.
  • the encoding module 201 is further configured to encode the signal as follows:
  • S1 The BCH code generated by the signal after the BCH encoding process and the transmitted information frame form a set bit information subframe, where the bit length of the information subframe does not meet the set bit length, according to the supplementary 0 code Way to fill it.
  • the b-bit BCH code output can be obtained by encoding the a-bit signal through BCH(b, a), and the b-bit BCH code and the transmitted information frame form a c-bit information subframe.
  • b can be set to 31 and c can be set to 223.
  • the information subframe is synchronously scrambled.
  • the scrambling code is an n-pseudo-random sequence. Adding the linear feedback of the n-sequence to the data can balance the number of occurrences of the 0 code and the 1 code. It can convert the data into approximately white noise and reduce the spatial signal fading and bit error rate. .
  • the scrambling code period of the synchronous scrambling process can be set to 2 15 -1, the polynomial is 1+X 14 +X 15 , the n sequence of the starting register value is 1001_0101_0000_000, and all the data after the frame is scrambled .
  • S3 The subframes subjected to the scrambling process are sequentially subjected to RS encoding and convolutional encoding.
  • Convolutional coding has 1 input port and 2 output ports.
  • FIG. 6 shows the coding block diagram of the RS code.
  • the input information polynomial h(x) is divided by g(x) to obtain the remainder r(x), and r(x) is spliced to the tail of h(x) to obtain the output.
  • Codeword Specifically, h(x) is directly output through the gate A, and h(x) enters the RS verification circuit. At this time, the output of the verification circuit is disconnected. When all 223 elements enter the verification circuit, several registers are stored The data is the RS check digit. At this time, the output of the check circuit is open, and the check bit is output to complete r(x) splicing to the tail of h(x), thereby forming 255-bit RS coded data.
  • FIG. 7 shows a coding block diagram of a convolutional code.
  • the code rate is 3/4 bits/symbol
  • the constraint length is 7 bits
  • the output is determined by the puncturing scheme, where C1: 101, C2: 110, 1 represents the transmitted symbol, and 0 represents the symbol that is not transmitted.
  • the shift register is used to store bit information.
  • the output code stream sequence enters the shift register and divides the code stream sequence into two branches, and performs two XOR operations respectively.
  • the operation polynomial of the first branch is g1(x)
  • the operation polynomial of the second branch is g2(x).
  • the first branch and the second branch can send the operation results to the puncturing unit, where the operation results of the two branches enter the puncturing unit alternately, and the puncturing unit divides the continuous 6-bit data shift into a group, The order of entry for each group is C 1 (1)C 2 (1)C 1 (2)C 2 (2)C 1 (3)C 2 (3)... Finally, the puncturing unit performs convolution coding 3/4 puncturing and outputting on a set of data according to the puncturing scheme, and the output sequence is C 1 (1)C 2 (1)C 2 (2)C 1 (3)...
  • the data generated after convolutional encoding can be combined with a 320-bit carrier synchronization bit, a 160-bit pilot sequence, a 64-bit unique code, and a 64-bit frame tail to form a complete modulated data frame.
  • the resulting combined coding method has low bit error rate, high confidentiality, and high spectrum utilization.
  • the present invention may also be a satellite communication system based on suppressing narrow-band interference.
  • the narrow-band satellite 1 may also receive a combined signal composed of multiple component signals.
  • the combined signal may include a demand signal and an interference signal.
  • the demand signal refers to a signal that needs to be relayed and transmitted through the narrow-band satellite 1.
  • the narrowband satellite 1 further includes an analog-to-digital conversion module 105, a windowing module 106, a separation module 107, a regeneration module 108, a delay module 109, a cancellation module 110, and an inversion module 111.
  • Multi-channel transmission is established between the narrow-band satellite 1 and the ground station 2.
  • the signals transmitted by the multi-channel can have frequency overlap with each other, which can improve the utilization rate of spectrum resources.
  • the narrow-band satellite 1 is configured to perform separation processing on the combined signal with frequency overlap as follows:
  • S1 Perform windowing processing based on the windowing module 106 to obtain a window processing signal, and perform nth power processing on the window processing signal based on the interference detection module 101 to determine the modulation characteristic of the component signal and the symbol rate of the carrier corresponding to the component signal.
  • the analog-to-digital conversion module 105 is used to perform analog-to-digital conversion on the combined signal received by the narrowband satellite to convert the analog signal into a digital signal.
  • the combined signal received by the narrowband satellite 1 is first transmitted to the analog-to-digital conversion module 105 for analog-to-digital conversion processing to generate a digital signal.
  • the windowing module 106 can receive the digital signal generated by the analog-to-digital conversion module 105.
  • the windowing module 106 can limit the bandwidth of the digital signal or pay attention to a part of the digital signal to ensure that it can effectively process the spectrum part of the demand signal, and then can Generate window processing signals.
  • the interference detection module 101 can receive the window processing signal and identify and determine its signal components.
  • the interference detection module 101 may be configured to perform n-th power processing on the window processing signal until it is converted into a continuous wave.
  • the window processing signal contains a variety of different signals, for example, it may contain two demand signals and three interference signals. Different signals have different modulation characteristics, and thus can form multiple different n-th power processing, that is, the window
  • the processed signal may obtain a continuous wave when performing the fourth power processing, and another continuous wave when performing the eighth power.
  • the window processing signal with 5 kinds of signals can generate 5 continuous waves independent of each other in 5 different nth powers.
  • the n-th power processing is executed in multiples of 2, that is, the power-of-two processing, power-of-four processing, power-of- six processing, etc. can be executed.
  • the n-th power processing when the n-th power processing is performed, it is performed in a manner that each stage is incremented by 2 stages.
  • the modulation characteristic of the component signal can be determined at least by one or more of phase offset, frequency offset, bandwidth and time delay of the component signal.
  • the waveform of the continuous wave formed after the nth power processing can determine the phase offset, frequency offset, bandwidth and time delay.
  • the symbol rate of the window processing signal may be determined based on the nth power processing process of the window processing signal. For example, when the signal is performing n-th power processing, the phases of the symbols will be correlated or the correlation between them will be eliminated, and then a continuous wave represented by a single frequency in the frequency domain can be formed. This process can produce a distribution. For the small side lobes around the frequency of the continuous wave, the interval between the small side lobes is related to the symbol rate of the carrier of the corresponding component signal, and the symbol rate of the carrier can be determined based on the interval between the small side lobes.
  • the separation module 107 resamples the window processing signal in a manner based on m times of the symbol rate to generate a resampled signal, and determines at least One symbol track and at least one modulation type.
  • the window processing signal may be transmitted to the separation module 107, and the separation module may process the signal in a manner of m times the symbol rate based on the determined modulation characteristics Resample. That is, the separation module 107 samples its received signal at a higher rate, and can then derive the symbol trajectory, shaping factor, and modulation type.
  • the shaping factor can be used to evaluate the degree of concentration or dispersion of signal energy.
  • the shaping factor may be the root-raised cosine spectrum of the window processed signal.
  • signals with different components can generate multiple continuous waves in different n-th power processing.
  • a continuous wave when using binary phase keying to modulate a signal, a continuous wave can be generated when the power is processed twice.
  • quadrature phase shift keying when using quadrature phase shift keying to modulate the signal, continuous waves can be generated during the fourth power processing. Therefore, the modulation type of the signal can be determined according to the number of times of self-multiplication processed by the nth power.
  • the value of m may be an integer greater than 2.
  • the regeneration module 108 synthesizes each component signal based on at least one symbol trajectory and at least one modulation type to generate a composite signal.
  • the inversion module 111 performs inversion processing on the composite signal
  • the delay module 109 delays the transmission of the copy of the digital signal to the cancellation module 110, and the cancellation module 110 superimposes the inverted copy with the copy of the digital signal to eliminate the interference signal, thereby obtaining the first-level interference Suppress the signal.
  • the first-level interference suppression signal can be transmitted to the signal preprocessing module 101 for processing to separate the time-frequency content of the transmitted signal from the frequency content of the interference signal.
  • the first-level interference suppression signal processed by the signal preprocessing module 101 can be transmitted to the interference cancellation module 102 to further eliminate the interference signal.

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Abstract

一种窄带多通道卫星通信系统，信号经地面站传输至至少一个窄带卫星，地面站至少包括编码模块和第一调制模块，地面站被配置为：编码模块配置为对信号执行编码处理以获取编码信号；第一调制模块配置为将编码信号执行串并变换处理以生成第一支路码流和第二支路码流，其中：在第一支路码流执行延迟处理以使得第一支路码流和第二支路码流彼此之间间隔设定码元周期的情况下，第一支路码流依次执行第一级滤波处理和第一级调制处理获取第一调制信号，第二支路码流依次执行第一级滤波处理和第二级调制处理获取第二调制信号；第一调制信号和第二调制信号共同经第二级调制处理以获得第三调制信号，其中，第三调制信号经第二级滤波处理以完成调制处理。

Description

一种卫星通信系统 技术领域
本发明属于无线通信技术领域，尤其涉及一种卫星通道系统。
背景技术
空间频谱资源是有限的，卫星通信的数据传输速率的提升是以牺牲信息的带宽为代价的，从而其不断对频谱资源进行巨大冲击。为了避免多个发射机发射同一频段信号而导致同频信号相互干扰，使得接收机无法调节正确信息。为了解决现有问题，常采用频谱固定分配模式，即将固定频段的使用权归于特定用户并禁止其他用户或者服务接入已被划分的频谱。固定频段分配模式十分有效地解决了无线电使用中产生的干扰。但随着无线技术的快速发展，越来越多的服务需要接入频谱，原来的频谱的静态分配管理模式使得频谱资源无法得到充分利用，从而使频谱资源越发显得短缺。因此，频谱利用率高、传输速率快且传输距离远的窄带通信技术的研究已成为必然。
OFDM(正交频分复用)为一种调制技术，利用多载波的传送方式，将一数据串通过低传输速率的子载波来传送。OFDM技术采用一种不连续的多音调制技术，将不同频率的载波中的大量信号合并成单一信号，完成信号传送。OFDM技术发展是为了提高载波的频谱利用率，其特点是各子载波相互正交，于是扩频调制后的频谱可以相互重叠，因而减小子载波之间的相互干扰。WiMAX通信系统就是基于OFDM调制技术的通信系统。使用OFDM的重要关键之一是可增加抵抗频率选择性衰落能力，同时也增加了抵制窄带干扰的能力。但是OFDM系统自身能够抗窄带干扰的条件是假设OFDM信号的功率与窄带干扰相比大得多；然而实际应用中，OFDM信号的发射功率是受限的，这样当外界的窄带干扰信号足够强时将会恶化正常解调性能。因此在有限的频谱资源中如何抑制窄带干扰是不可忽视的问题。
窄带强干扰在实际应用中是常见的干扰，对其抑制可以在时域或频域中完成。时域方法利用窄带干扰的相关性，进行最小均方算法或者递推最小二乘算法自适应滤波。频域方法则通过快速傅立叶变换或者快速傅立叶逆变换将干扰所处频点置零以消除干扰。具体的，常见的频域滤波主要有以下两种方式：第一种方式，简单的基于FFT/IFFT的干 扰抑制技术，将数据通过加窗处理、FFT计算、NBI滤波处理以及IFFT计算后输出，第二种方式，为减小加窗导致的信噪比损失，基于叠加的快速傅立叶变换的干扰抑制技术被提出来。基本思想是将输入数据复制并移位加窗，与原加窗数据一起得到两个加窗数据，进行FFT变换，并在频域进行滤波，滤波后进行IFFT得到去除干扰的时域数据，最后将两路数据对齐合并得到最终输出。
公开号为CN105549035B的专利文献公开了一种基带信号频域窄带干扰检测消除装置及方法，所述方法包括：将中频信号分为两路，分别输出给窄带干扰检测器与窄带干扰消除器，所述窄带干扰检测器对接收的一路中频信号进行干扰检测，得到干扰检测信息，并将其发送给所述窄带干扰消除器，所述窄带干扰消除器根据所述干扰检测信息对接收的另一路中频信号进行窄带干扰消除处理。该发明在进行快速傅立叶变换处理之前将信号的时域乘以窗函数以进行加窗处理，时域中的乘法运算等效于频域中的卷积处理，因此加窗的效果仅仅是减少干扰源产生的旁瓣。加窗处理可以提高的性能取决于干扰源的频率。当干扰源并不位于某一个子载波频率上，则会产生频谱泄露，并且窄带干扰会影响所有的相邻子载波。并且其也并未考虑对载波间干扰进行消除处理。
发明内容
如本文所用的词语“模块”描述任一种硬件、软件或软硬件组合，其能够执行与“模块”相关联的功能。
针对现有技术之不足，本发明提供一种卫星通信系统，尤其是一种窄带多通道卫星通信系统，信号能够经地面站传输至至少一个窄带卫星，若干个地面站彼此之间能够基于所述窄带卫星的中继而通信地耦合，所述地面站至少包括编码模块和第一调制模块，所述地面站被配置为按照如下方式对所述信号进行调制处理：所述编码模块配置为对所述信号执行编码处理以获取编码信号；所述第一调制模块配置为将所述编码信号执行串并变换处理以生成第一支路码流和第二支路码流，其中：在所述第一支路码流执行延迟处理以使得所述第一支路码流和所述第二支路码流彼此之间间隔设定码元周期的情况下，所述第一支路码流依次执行第一级滤波处理和第一级调制处理获取第一调制信号，所述第二支路码流依次执行所述第一级滤波处理和第二级调制处理获取第二调制信号；所述第一调制信号和所述第二调制信号共同经所述第二级调制处理以获得第三调制信号，其中，所述第三调制信号经所述第二级滤波处理以完成所述调制处理。第一级滤波处理由升余弦滚降滤波器执行，第二级滤波处理由带通滤波器执行。信号经第一级滤波处理后会由于后续的调制重采样过程而使得信号频谱出现周期延拓现象，最终产生码间干扰， 并且在调制信号的频率范围内会存在旁瓣干扰，降低了调制信号的质量，使得误码率升高。第二级滤波处理能够将频率范围内的旁瓣大小降低至指定的分贝范围内，能够消除码间干扰。调制生成的第三调制信号相比于现有技术具有更低的平均功率比峰值。并且通过第一级滤波处理能够有效地将第一支路码流和第二支路码流的任何相位的不连续性进行平滑移除。
有利地，所述编码模块被配置为按照如下方式对所述信号执行编码处理：所述信号经BCH编码处理生成的BCH码与发送信息帧共同构成设定比特的若干个信息子帧，所述信息子帧经同步加扰处理以依次执行RS编码处理和卷积编码处理，卷积编码后的数据与载波同步比特、引导序列、独特码、帧尾共同组成完整的调制数据帧，其中：在所述信息子帧的比特长度小于设定比特长度的情况下，按照补充零码的方式对其进行补齐。
有利地，所述地面站还包括滤波模块、第二调制模块和变频模块，所述地面站还按照如下方式对所述信号进行处理：所述编码信号以设定码速率传输至第一调制模块中执行调制处理后以第一载波频率传输至所述滤波模块；所述滤波模块配置为对其接收的信号执行滤波处理并传输至所述第二调制模块；所述第二调制模块以第二载波频率将其接收的信号传输至所述变频模块，其中，所述变频模块配置为将其接收的信号变频至设定的射频输出频率。
有利地，所述窄带卫星至少包括信号调节模块和干扰消除模块，在所述信号经所述地面站传输至所述窄带卫星的情况下，所述窄带卫星配置为按照如下方式对所述信号执行处理：将所述信号调节模块配置为：确定所述信号的频率成分并获取若干个不同时频空间的分解信号以将干扰信号的频率内容进行分离。将所述干扰消除模块配置为：将干扰信号的频率与通信信道的子载波频率中心对准并建立第一复正弦曲线，并基于所述第一复正弦曲线与所述信号的乘法处理以获取偏移信号并以此引入载波间干扰；将所述偏移信号依次执行加窗处理和快速傅立叶变换处理以生成频域信号，所述频域信号能够按照子载波频率置零的方式消除所述干扰信号以获取干扰消除信号；在所述干扰消除信号经快速傅立叶逆变换处理以产生时域采样样本的情况下，建立第二复正弦曲线并按照所述第二复正弦曲线与所述时域采样样本执行乘法处理的方式消除所述载波间干扰。
有利地，所述信号调节模块按照如下步骤获取所述分解信号：配置具有若干个不同滤波等级的滤波器组，并且每个滤波等级至少包括低通信道和高通信道，所述低通信道和所述高通信道均配置至少一组离散小波变换器，其中：基于所述滤波器组的若干个的滤波等级将获取若干个不同频段的子带；所述子带所包含的信号能够分别经离散小波变 换处理分解至若干个不同的时频空间。
有利地，所述第一复正弦曲线经公式
Figure PCTCN2019121951-appb-000001
限定，所述第二复正弦曲线经公式
Figure PCTCN2019121951-appb-000002
限定；BCH编码的生成多项式为g(x)＝x 10+x 9+x 8+x 6+x 5+x 3+1；RS编码的生成多项式为g(x)＝x 8+x 4+x 3+x 2+1；卷积编码的两个输出端口的生成多项式分别为g1(x)＝x 6+x 5+x 4+x 3+1和g2(x)＝x 6+x 4+x 3+x 1+1；同步加扰处理的扰码周期和多项式分别为为2 15-1和1+X 14+X 15；其中，F s表示采样频率，N是快速傅立叶变换采样点数。
有利地，所述第一级滤波处理经第一滤波器执行，所述第二级滤波处理经第二滤波器执行，其中：所述第一滤波器是升余弦滚降滤波器，所述第二滤波器是带通滤波器；所述第一级调制处理是正交调制处理，所述第二级调制处理是同相调制处理。
有利地，所述窄带卫星还包括干扰检测模块和解调模块，所述干扰检测模块配置为计算信号的平均功率以确定子带中是否存在干扰信号，所述解调模块配置为对所述干扰消除模块的输出信号进行解调处理。
有利地，所述干扰消除模块还被配置为获取与干扰信号的频率最接近的快速傅立叶变换滤波器组的频率Δf，其中：所述第一复正弦曲线的频率为Δf，所述第二复正弦曲线的频率为-Δf。
有利地，针对所述快速傅立叶变换滤波器组的频率Δf计算过程中所涉及的子载波频率，干扰消除模块能够将该子载波频率所对应的快速傅立叶转换滤波器组频率设置为零以将所述干扰信号消除。
本发明还提供了一种卫星通信系统，尤其是一种窄带卫星通信系统，至少包括窄带卫星和地面站，所述窄带卫星被配置为在信号的中继过程中至少对所述信号进行干扰抑制处理以实现所述信号在若干个地面站彼此之间的传输，所述地面站将其接收到的信号变频至若干个彼此不同的射频输出频率以与所述窄带卫星彼此之间建立多通道传输，其中，所述窄带卫星被配置为：分别建立第一复正弦曲线和第二复正弦曲线，并确定所述信号的频率成分以对干扰信号的频率内容进行分离；基于第一复正弦曲线与所述信号的第一级乘法处理获取第一处理信号并引入载波间干扰；按照子载波频率置零的方式消除所述干扰信号以获取第二处理信号；在所述第二处理信号经快速傅立叶逆变换处理的情况下，基于第二复正弦曲线与所述第二处理信号的第二级乘法处理消除所述载波间干扰。
有利地，所述窄带卫星还被配置为：将干扰信号的频率与通信信道的子载波频率中 心对准；获取与所述干扰信号的频率最接近的快速傅立叶变换滤波器组的频率Δf；按照将所述子载波频率所对应的快速傅立叶变换滤波器组的频率Δf置零的方式消除所述干扰信号。
有利地，所述窄带卫星还被配置为：配置具有若干个不同滤波等级的滤波器组，并且每个滤波等级至少包括低通信道和高通信道，所述低通信道和所述高通信道均配置至少一组离散小波变换器，其中：基于所述滤波器组的若干个滤波等级获取若干个不同频段的子带；所述子带所包含的信号能够分别经离散小波变换处理分解至若干个不同的时频空间以对干扰信号的频率内容进行分离。
有利地，所述地面站至少包括编码模块、第一调制模块和滤波模块，所述地面站被配置为按照如下方式对其接收到的信号进行处理：所述编码模块至少按照BCH编码处理、RS编码处理和卷积编码处理进行共同处理的方式对信号进行编码处理以获取编码信号；所述第一调制模块对所述编码信号进行调制处理并以第一载波频率传输至所述滤波模块，其中：在基于所述编码信号获取彼此之间间隔设定码元周期的第一支路码流和第二支路码流的情况下，至少基于所述第一支路码流和所述第二支路码流分别获取第一调制信号和第二调制信号；所述第一调制信号和所述第二调制信号按照依次执行调制处理和滤波处理的方式获取满足所述第一载波频率的第三调制信号。
有利地，所述编码信号按照执行串并变换处理的方式获取所述第一支路码流和所述第二支路码流，所述第一支路码流或所述第二支路码流能够按照执行延迟处理的方式而彼此间隔设定码元周期，其中：在所述第一支路码流执行所述延迟处理的情况下，所述第一支路码流按照依次执行第一级滤波处理和第二级调制处理的方式获取所述第一调制信号，所述第二支路码流按照依次执行所述第一级滤波处理和第二级调制处理的方式获取所述第二调制信号；所述第一调制信号和所述第二调制信号按照依次执行第二级调制处理和第二级滤波处理的方式获取所述第三调制信号。第一级滤波处理由升余弦滚降滤波器执行，第二级滤波处理由带通滤波器执行。信号经第一级滤波处理后会由于后续的调制重采样过程而使得信号频谱出现周期延拓现象，最终产生码间干扰，并且在调制信号的频率范围内会存在旁瓣干扰，降低了调制信号的质量，使得误码率升高。第二级滤波处理能够将频率范围内的旁瓣大小降低至指定的分贝范围内，能够消除码间干扰。调制生成的第三调制信号相比于现有技术具有更低的平均功率比峰值。并且通过第一级滤波处理能够有效地将第一支路码流和第二支路码流的任何相位的不连续性进行平滑移除。
有利地，所述编码处理至少包括如下步骤：信号经所述BCH编码处理以生成BCH 码，所述BCH码与发送信息帧按照补充零码的方式共同构成设定比特的若干个信息子帧；在所述信息子帧依次经同步加扰处理、RS编码处理和卷积编码处理以得到处理数据的情况下，所述处理数据至少与载波同步比特、引导序列、独特码和帧尾共同组成完整的调制数据帧。
有利地，所述地面站还包括第二调制模块和变频模块，所述滤波模块至少包括第一滤波器和第二滤波器，其中：所述滤波模块按照所述第一滤波器对所述第一支路码流和所述第二支路码流执行所述第一级滤波处理并且所述第二滤波器对所述第三调制信号执行所述第二级滤波处理的方式对其接收的信号进行滤波处理；在所述第三调制信号经所述滤波模块传输至所述第二调制模块的情况下，所述第二调制模块以第二载波频率将其接收的信号传输至所述变频模块；所述变频模块将其接收的信号变频至设定的射频输出频率。
针对现有技术之不足，本发明提供一种基于抑制窄带干扰的卫星通信系统，窄带卫星与地面站按照多通道的方式彼此通信连接以对具有若干个组成信号的组合信号进行中继传输，其特征在于，所述窄带卫星被配置为：
分别建立第一复正弦曲线和第二复正弦曲线，并确定所述信号的频率成分以对干扰信号的频率内容进行分离；基于第一复正弦曲线与所述信号的第一级乘法处理获取第一处理信号并引入载波间干扰；按照子载波频率置零的方式消除所述干扰信号以获取第二处理信号；
在所述第二处理信号经快速傅立叶逆变换处理的情况下，基于第二复正弦曲线与所述第二处理信号的第二级乘法处理消除所述载波间干扰；
其中，所述窄带卫星至少包括干扰检测模块、加窗模块、分离模块和再生模块，在所述组成信号彼此之间具有频率重叠的情况下，所述窄带卫星被配置为按照如下方式对所述组合信号进行处理：所述加窗模块配置为基于加窗处理对所述组合信号的频率进行限定后生成窗处理信号；所述干扰检测模块配置为基于所述窗处理信号的n次幂处理以确定至少一个组成信号的调制特性及其对应的载波的符号率；所述分离模块配置为在所述窗处理信号基于所述n次幂处理产生至少一个连续波的情况下，基于所述符号率的m倍的方式对所述窗处理信号重采样并生成重采样信号，并以此确定至少一个符号轨迹和至少一个调制类型；所述再生模块配置为基于所述符号轨迹和所述调制类型对所述组成信号进行合成再生以生成合成信号。
有利地，所述窄带卫星还包括消除模块和反转模块，在确定所述合成信号为干扰信 号的情况下，所述窄带卫星被配置为按照如下方式对所述合成信号进行处理：所述反转模块配置为对所述合成信号进行反转处理以生成反转副本；所述消除模块配置为接收所述组合信号的副本并将所述反转副本和所述组合信号的副本进行叠加处理以生成第一级干扰抑制信号。
有利地，所述窄带卫星还包括信号预处理模块和干扰消除模块，所述窄带卫星被配置为按照如下方式对所述第一级干扰抑制信号进行处理：所述信号预处理模块配置为建立第一复正弦曲线和第二复正弦曲线，并确定所述第一级干扰抑制信号的频率成分以对干扰信号的频率内容进行分离。所述干扰消除模块配置为：按照所述第一干扰抑制信号与所述第一复正弦曲线的执行乘法处理以生成偏移信号的方式引入载波间干扰；按照子载波频率置零的方式获取干扰消除信号并获取其时域采样样本；按照所述时域采样样本与所述第二复正弦曲线执行乘法处理的方式消除所述载波间干扰。
有利地，所述干扰消除模块按照如下方式获取所述干扰消除信号：将干扰信号的频率与通信信道的子载波频率中心对准并获取与所述干扰信号的频率最接近的快速傅立叶变换滤波器组的频率Δf；将所述偏移信号依次执行加窗处理和快速傅立叶变换处理以生成频域信号；将所述子载波频率所对应的快速傅立叶变换滤波器组的频率Δf置零。
有利地，所述信号预处理模块被配置为：配置具有若干个不同滤波等级的滤波器组，并且每个滤波等级至少包括低通信道和高通信道，所述低通信道和所述高通信道均配置至少一组离散小波变换器，其中：基于所述滤波器组的若干个滤波等级获取若干个不同频段的子带；所述子带所包含的信号能够分别经离散小波变换处理分解至若干个不同的时频空间。
有利地，所述地面站至少包括编码模块和第一调制模块，所述地面站被配置为按照如下方式对所述信号进行调制处理：所述编码模块配置为对所述信号执行编码处理以获取编码信号；所述第一调制模块配置为将所述编码信号执行串并变换处理以生成第一支路码流和第二支路码流，其中：在所述第一支路码流执行延迟处理以使得所述第一支路码流和所述第二支路码流彼此之间间隔设定码元周期的情况下，所述第一支路码流依次执行第一级滤波处理和第一级调制处理获取第一调制信号，所述第二支路码流依次执行所述第一级滤波处理和第二级调制处理获取第二调制信号；所述第一调制信号和所述第二调制信号共同经所述第二级调制处理以获得第三调制信号，其中，所述第三调制信号经所述第二级滤波处理以完成所述调制处理。第一级滤波处理由升余弦滚降滤波器执行，第二级滤波处理由带通滤波器执行。信号经第一级滤波处理后会由于后续的调制重采样 过程而使得信号频谱出现周期延拓现象，最终产生码间干扰，并且在调制信号的频率范围内会存在旁瓣干扰，降低了调制信号的质量，使得误码率升高。第二级滤波处理能够将频率范围内的旁瓣大小降低至指定的分贝范围内，能够消除码间干扰。调制生成的第三调制信号相比于现有技术具有更低的平均功率比峰值。并且通过第一级滤波处理能够有效地将第一支路码流和第二支路码流的任何相位的不连续性进行平滑移除。
有利地，所述编码处理至少包括如下步骤：信号经BCH编码处理以生成BCH码，所述BCH码与发送信息帧按照补充零码的方式共同构成设定比特的若干个信息子帧；在所述信息子帧依次经同步加扰处理、RS编码处理和卷积编码处理以得到处理数据的情况下，所述处理数据至少与载波同步比特、引导序列、独特码和帧尾共同组成完整的调制数据帧。
有利地，所述地面站还包括滤波模块、第二调制模块和变频模块，所述地面站还按照如下方式对所述信号进行处理：所述编码信号以设定码速率传输至第一调制模块中执行调制处理后以第一载波频率传输至所述滤波模块；所述滤波模块配置为对其接收的信号执行滤波处理并传输至所述第二调制模块；所述第二调制模块以第二载波频率将其接收的信号传输至所述变频模块，其中，所述变频模块配置为将其接收的信号变频至设定的射频输出频率。
有利地，所述窄带卫星还包括解调模块，所述干扰检测模块配置为计算信号的平均功率以确定子带中是否存在干扰信号，所述解调模块配置为对所述干扰消除模块的输出信号进行解调处理，其中：所述第一复正弦曲线的频率为Δf，所述第二复正弦曲线的频率为-Δf。
有利地，所述滤波模块按照第一滤波器对所述第一支路码流和所述第二支路码流执行所述第一级滤波处理并且第二滤波器对所述第三调制信号执行所述第二级滤波处理的方式对其接收的信号进行滤波处理；在所述第三调制信号经所述滤波模块传输至所述第二调制模块的情况下，所述第二调制模块以第二载波频率将其接收的信号传输至所述变频模块；所述第一滤波器是升余弦滚降滤波器，所述第二滤波器是带通滤波器；所述第一级调制处理是正交调制处理，所述第二级调制处理是同相调制处理。
本发明的卫星通信系统的有益技术效果为：
(1)本发明在迭代过程中，每个窄带干扰信号与通信信道的子载波频率中心对准时便会导致载波间干扰的产生。将窄带干扰对准的子载波频率去除后信号将不再携带该窄带干扰，随后从信号中将载波间干扰移除。因此，在解码之前，信号便去除了所有的窄 带干扰以及任何潜在的旁瓣，进而能够消除频谱泄露。
(2)本发明通过数字成形滤波器可以消除码间干扰，进而能够满足无码间干扰的奈奎斯特特性，同时还可以平滑波形，进而能够加快调制信号的频带外衰减速度，提高频谱利用率。通过带通滤波器的处理可以使得调制包络更加圆滑。
(3)本发明能够接收具有频率重叠的信号，并对其中所包含的干扰信号进行检测和滤除，能够有效地提高频谱资源的利用率。
附图说明
图1是本发明优选的窄带多通道卫星通信系统的模块化连接关系示意图；
图2是本发明优选的地面站的模块化结构示意图；
图3是本发明优选的第一调制模块的调制处理流程示意图；
图4是本发明优选的窄带卫星的模块化结构示意图；
图5是本发明优选的干扰消除模块的处理流程示意图；
图6是本发明优选的RS码的编码框图；
图7是本发明优选的卷积码的编码框图；
图8是本发明优选的编码模块的处理流程示意图；
图9是本发明优选的另一种窄带卫星的模块化结构示意图；和
图10是本发明优选的窄带卫星对组合信号的处理流程示意图。。
                附图标记列表
1：窄带卫星                2：地面站
101：干扰检测模块        102：干扰消除模块     103：解调模块
104：信号调节模块       105：模数转化模块     106：加窗模块
107：分离模块            108：再生模块        109：延迟模块
110：消除模块            111：反转模块
201：编码模块            202：第一调制模块     203：滤波模块
204：第二调制模块        205：变频模块
102a：偏移逻辑电路      102b：第一乘法器      102c：窗函数电路
102d：第一快速傅立叶变换电路 102e：干扰消除电路
102f：快速傅立叶逆变换电路 102g：校正电路 102h：第二乘法器
102i：第二快速傅立叶变换电路
2a：第一地面站            2b：第二地面站
203a：第一滤波器      203b：第二滤波器
202a：第一调制器      202b：第二调制器    202c：第三调制器
具体实施方式
下面结合附图进行详细说明。
本发明中的各个“模块”，分别可以是专用集成芯片、服务器、服务器组中的一种或几种。本发明的模块描述任一种硬件、软件或软硬件组合，其能够执行与“模块”相关联的功能。
根据一种可行方式，本发明提供一种多通道卫星通信系统，至少包括至少一个窄带卫星1和若干个彼此通信的地面站2。例如，如图1所示，多通道卫星通信系统包括窄带卫星1、第一地面站2a和第二地面站2b。第一地面站2a可以将其接收到的数据信号发送至窄带卫星1，进而通过窄带卫星1将其中继至第二地面站2b。同理，第二地面站2b也可以将其接收到的数据信号通过窄带卫星1中继到第一地面站2a。第一地面站2a和第二地面站2b可以单独具有其各自的网关，并且所有网关可以通过共同的网络彼此通信地耦合在一起。
优选的，如图2所示，地面站2至少包括编码模块201、第一调制模块202、滤波模块203、第二调制模块204和变频模块205。编码模块201用于对地面站2接收到的原始数据信息进行编码并将编码后的数字信号按照设定的码速率传输至第一调制模块202。第一调制模块202用于对数字信号进行调制以将转变至设定的第一载波频率。经第一调制模块202调制后的数字信号传输至滤波模块203中进行滤波处理。经滤波模块203编码模块201滤波处理后的数字信号传输至第二调制模块204中进行再次调制以转变至设定的第二载波频率。具有第二载波频率的数字信号传输至变频模块205中。变频模块205用于将第二调制模块204处理得到的数字信号变频至设定的发射频点以便于将其上传至窄带卫星1。
优选的，编码模块201可以被配置为基于循环编码或卷积编码对原始数据信息进行编码。第一调制模块202和第二调制模块204可以基于数字相位调制、多进制数字相位调制、相移键控调制、正交相位键控调制、偏移正交相移键控调制中的一种或多种的组合对数字信号进行调制。滤波模块203可以是数字成形滤波器，通过数字成形滤波器可以消除码间干扰，进而能够满足无码间干扰的奈奎斯特特性，同时还可以平滑波形，进而能够加快调制信号的频带外衰减速度，提高频谱利用率。
优选的，变频模块205可以是可编程锁相环芯片，通过配置锁相环芯片的分频寄存 器的参数可以将调制信号变频至设定的射频输出频率范围，同时再通过设置频率划分间隔便可以将可用频谱等频率间隔的分割为若干个载波信道。将频谱划分为多个通道可以提升频谱的利用率。例如，若可用频段为100.0000MHz～100.0100MHz，若频率划分间隔为100Hz，则可以将该频段划分为100个信道。通过变频模块可以得到窄带信号。进而实现地面站2与窄带卫星1彼此之间的窄带多通道通信。
优选的，地面站2可以将原始数据经编码模块的编码处理后以600bps的码速率送入第一调制模块202中进行调制处理。第一调制模块202以15KHz的载波频率传输至滤波模块203中进行滤波处理。第二调制模块204将15KHz的调制信号进行再次调制以使得其以10.685MHz的载波频率传输至变频模块205。
优选的，如图3所示，第一调制模块202还被配置为按照如下的工作方式对编码模块201处理得到的编码信号进行调制处理：
S1：编码信号经串并变换处理以生成第一支路码流和第二支路码流，其中，第一支路码流和第二支路码流按照延迟处理的方式彼此间隔设定码元周期。
具体的，编码信号经过串并变换处理生成第一支路码流和第二支路码流后，第一支路码流和第二支路码流各自的码速率为编码信号码速率的二分之一。第一支路码流可以按照串行传输的方式进行信号传输，第二支路码流可以按照并行传输的方式进行信号传输。设定码元周期可以是半个码元周期。将第一支路码流或第二支路码流中的任意一个经过半个码元周期的延时处理后便能将第一支路码流和第二支路码流错开半个码元周期。
S2：在将第一支路码流进行半个码元周期的延时处理的情况下，第一支路码流和第二支路码流按照一一对应的方式分别传输至滤波模块203中进行滤波处理，其中，滤波模块203至少包括第一滤波器203a和第二滤波器203b，第一支路码流和第二支路码流按照一一对应的方式传输至第一滤波器203a中进行滤波处理。通过第一滤波器203a可以执行第一级滤波处理。
具体的，第一滤波器203a是数字成形滤波器。数字成形滤波器可以是升余弦滚降滤波器，通过控制滚降系数，能够改变编码信号的成形波形，从而能够减小抽样定时误差造成的影响。升余弦滚降滤波器的频率响应H(f)可以通过如下公式表示：
Figure PCTCN2019121951-appb-000003
其中，对应的时域波形函数为：
Figure PCTCN2019121951-appb-000004
其中，码元周期T s＝1/2f N，f N为奎奈斯特频率。α为滚降因子，其决定H(f)的形状，α在[0，1]间取值。当α较大时，时域波形衰减块并且振荡起伏较小，其有利于减小码间干扰和定时误差的影响，但占用频带变宽，频带利用率降低，并且带内噪声对信号的影响也会相应增大。当α较小时，频带利用率增加，带内噪声的影响得到削弱，但波形振荡起伏增大，对码间干扰和定时误差的影响增大，最终导致误码率的提高。优选的，滚降因子α可以选取为0.5，数字成形滤波器的阶数设置为32阶。
S3：经过第一滤波器203a进行滤波处理后的第一支路码流和第二支路码流分别传输至第一调制模块202中进行调制处理。
具体的，第一调制模块202至少包括第一调制器202a、第二调制器202b和第三调制器202c。第一调制器202a是正交调制器，第二调制器202b和第三调制器202c均是同相调制器。第一支路码流传输至第一调制器202a中进行正交调制处理以得到第一调制信号，第二支路码流传输至第二调制器中进行同相调制处理以得到第二调制信号。第一调制信号和第二调制信号均统一传输至第三调制器202c中进行同相调制处理以得到第三调制信号。通过第一调制器202a可以执行第一级调制处理。通过第二调制其202b和第三调制器202c可以执行第二级调制处理。
S4：第三调制信号传输至第二滤波器203b中进行滤波处理以完成对编码信号的调制处理。
具体的，第二滤波器203b是带通滤波器，其允许特定频率范围内的信号通过，能够将特定频率范围外的信号衰减至很低水平。编码信号基于调制模块的调制重采样过程，使得信号频谱会出现周期延拓而产生码间干扰，进而导致调制模块的误码概率增加。优选的，带通滤波器的阶数可以设定为64阶。通过带通滤波器的处理可以使得调制包络更加圆滑。通过第二滤波器203b可以执行第二级滤波处理。
根据一个可行方式，再次参见图1，第一地面站2a可以将第一信号发送给窄带卫星1，进而通过窄带卫星1将第一信号中继至第二地面站2b。当第二地面站2b将第二信号传输至窄带卫星时，第二地面站2b能够同时接收到第二信号的回波和第一信号作为组合信号。同理，第一地面站2a能够同时接收到第一信号的回波和第二信号作为组合信号。第一地面站2a和第二地面站2b可以通过回波消除方法以消除由于回波导致的干扰，通 过消除回波可以利于第一信号和第二信号的解调。第一信号和第二信号在传输过程中会受到不同环境和不同程度的干扰，从而导致地面站接收到的组合信号至少需要传输的发射信号、发射信号的回波以及噪声基底。需要传输的发射信号是指需要在第一地面站和第二地面站之间进行传输的第一信号或第二信号。噪声基底是指通信系统中所有的噪声源和不需要的信号的总和，即除发射信号之外的任何其他信号。
优选的，如图4所示，窄带卫星1至少包括信号调节模块104。信号调节模块104包括若干个滤波器以实现对组合信号的分解、分析或抑制干扰信号。信号调节模块104被配置为按照如下方式对组合信号进行处理：
S1：对组合信号进行快速傅立叶变换处理以确定组合信号的频率成分。例如，信号调节模块104可以包括快速傅立叶变换器，将组合信号传输至快速傅立叶变换器便能够实现组合信号的快速傅立叶变换。快速傅立叶变换器可以将组合信号样本的乘积与频率的复正弦曲线相加以获取组合信号的频域表示，其中，快速傅立叶变换器的处理过程可以表示为：
Figure PCTCN2019121951-appb-000005
x n是组合信号的数字样本。N是正在处理的样本总数。
S2：经快速傅立叶变换处理后的输出信号经分解处理以获得多个不同时频空间的分解信号。具体的，输出信号可以传输进入滤波器组，滤波器组可以包括若干个不同的滤波等级。每个滤波等级可以包括低通信道和高通信道，并且低通信道和高通信道均分别配置一组离散小波变换器。通过不同的滤波等级能够将输出信号分割成若个个不同频段的子带，不同子带所包含的信号能够经离散小波变换器的离散小波变换处理而分解至多个不同时频空间，从而能够将发射信号的时频内容与干扰信号的频率内容进行分离。
优选的，再次参见图4，窄带卫星1至少包括干扰检测模块101、干扰消除模块102和解调模块103。窄带卫星1可以具有例如是天线的信号接收模块，进而能够接收地面站2或其他信号终端传输的信号。干扰检测模块101用于对信号调节模块104输出的若干个不同子带中信号进行干扰检测，进而能够确定组合信号中所存在的所有干扰源所对应的频率。干扰消除模块102用于针对干扰检测模块检测确定干扰源进行例如是滤波处理，从而实现干扰的消除。解调模块103用于对信号进行解调以便于信号的进一步传输。优选的，干扰检测模块101可以计算组合信号的平均功率并且设置标准阈值。当干扰检测模块分析确定的组合信号的实际功率高于设置的标准阈值，则可以判断存在干扰。可以通过对干扰信号进行的提前模拟来提前确定标准阈值的设定值。
优选的，如图5所示，干扰消除模块102可以包括偏移逻辑电路102a、第一乘法器102b、窗函数电路102c、第一快速傅立叶变换电路102d、干扰消除电路102e、快 速傅立叶逆变换电路102f和信号校正电路102g。偏移逻辑电路102a用于将干扰信号的频率与通信信道的子载波的频率中心进行对准，偏移逻辑电路能够确定干扰信号的频率与快速傅立叶转换滤波器组频率Δf的中心频率之间的差值，并且偏移逻辑电路可以从快速傅立叶转换滤波器组频率中确定与干扰信号的频率最为接近的一个或多个。优选的，偏移逻辑电路还能够创建关于接收到的信号的第一复正弦曲线以用于在第一乘法器102b中执行模拟信号彼此之间的相乘。第一复正弦曲线的频率可以用-Δf表示，并且第一复正弦曲线可以通过如下公式
Figure PCTCN2019121951-appb-000006
(n＝0，1，…，N-1)进行表示。F s表示采样频率。N是快速傅立叶变换采样点数。第一乘法器102b可以从偏移逻辑电路中接收第一复正弦曲线以及组合信号，其中，组合信号中包含干扰信号的采样样本。第一乘法器102b将第一复正弦曲线与采样样本相乘以获取偏移信号。同时，通过将第一复正弦曲线与采样样本相乘也能够将载波间干扰引入第一乘法器102b中。
优选的，窗函数电路102c用于接收第一乘法器102b的输出，并对其进行加窗处理。窗函数电路可以使用例如是汉宁窗函数、矩形窗函数或巴特利窗函数对信号进行加窗处理。通过加窗处理能够将第一乘法器102b的输出限制于主瓣上。第一快速傅立叶变换电路102d能够接收窗函数电路102c的输出，并对其执行快速傅立叶变换处理以生成频域信号。干扰消除电路102e能够接收由第一快速傅立叶变换电路102d处理后的解调的快速傅立叶变换信号，并且干扰消除电路102e能够将快速傅立叶变换信号中的由偏移逻辑电路102a在计算Δf过程中所确定的子载波频率进行移除以得到干扰消除信号。具体的，针对Δf计算过程中所涉及的子载波频率，干扰消除电路102e能够将该子载波频率所对应的快速傅立叶转换滤波器组频率设置为零。由于干扰信号的频率已经经偏移逻辑电路102a处理而与子载波的频率中心对准，而当前子载波的频率被干扰消除电路102e设定为零，从而使得干扰信号被消除。优选的，干扰消除信号能够传输至快速傅立叶逆变换电路102f并且被执行快速傅立叶逆变换处理以产生时域采样样本。优选的，校正电路102g被配置为生成频率等于Δf的斜坡信号，该斜坡信号可以通过第二复正弦曲线
Figure PCTCN2019121951-appb-000007
(n＝0，1，…，N-1)进行表示。从而校正电路102g能够消除载波间干扰。具体的，由校正电路102g生成的第二复正弦曲线与快速傅立叶逆变换电路102f生成的输出信号同时传输至第二乘法器102h中进行相乘处理以消除载波间干扰。优选的，第二乘法器102h的输出信号能够传输至第二快速傅立叶变换电路102i中再次进行快速傅立叶变换处理以对该信号进行解调处理。第二快速傅立叶变换电路102i的输出信号最终 传输至解调模块103中进行解码处理。优选的，第一快速傅立叶变换电路102d和第二快速傅立叶变换电路102i共同限定快速傅立叶转换滤波器组。
优选的，在迭代过程中，每个窄带干扰信号与通信信道的子载波频率中心对准时便会导致载波间干扰的产生。将窄带干扰对准的子载波频率去除后信号将不再携带该窄带干扰，随后从信号中将载波间干扰移除。因此，在解码之前，信号便去除了所有的窄带干扰以及任何潜在的旁瓣，进而能够消除频谱泄露。
根据一个可行方式，优选的，如图8所示，编码模块201还被配置为按照如下方式对信号进行编码处理：
S1：将信号经BCH编码处理后生成的BCH码与发送信息帧组成设定比特的信息子帧，其中，在信息子帧的比特长度不满足设定比特长度的情况下，按照补充0码的方式对其进行补齐。
具体的，a比特的信号经过BCH(b，a)编码能够得到b比特的BCH码输出，将b比特的BCH码与发送信息帧组成c比特的信息子帧。例如，b可以设定为31，c可以设置为223。
优选的，BCH码的生成多项式可以通过公式g(x)＝x 10+x 9+x 8+x 6+x 5+x 3+1进行表示。
S2：信息子帧经同步加扰处理。在数字通信中发送连续较长的0码或连续的1码时，会受到空间传输信道中存在的电磁场干扰，从而产生误码。扰码是一个n伪随机序列，将n序列的线性反馈和数据进行相加可以平衡0码和1码的出现次数，可以将数据转换成近似白噪声，降低了空间信号的衰落和误码率。具体的，同步加扰处理的扰码周期可以设定为2 15-1，多项式为1+X 14+X 15，起始寄存器值为1001_0101_0000_000的n序列，将成帧后的所有数据进行加扰处理。
S3：经加扰处理后的子帧依次进行RS编码和卷积编码。例如，RS编码的具体参数可以配置如下：码长n＝255，监督端k＝223，生成多项式g(x)＝x 8+x 4+x 3+x 2+1。卷积编码具有1个输入端口和2个输出端口，两个输出端口分别对应的生成多项式为g1(x)＝x 6+x 5+x 4+x 3+1和g2(x)＝x 6+x 4+x 3+x 1+1。
优选的，图6示出了RS码的编码框图，输入信息多项式h(x)去除g(x)得到余式r(x)，将r(x)拼接至h(x)的尾部，得到输出码字。具体的，h(x)通过选通器A直接输出，并且h(x)进入RS校验电路，此时校验电路的输出断路，当223个元素全部进入检验电路后，若干个寄存器中存放数据为RS校验位。此时校验电路的输出开路， 将校验位输出，完成r(x)拼接至h(x)的尾部，从而构成255比特的RS编码数据。
优选的，图7示出了卷积码的编码框图，码率为3/4比特/符号，约束长度为7比特，连接矢量G1＝1111001，G2＝1011011。输出由打孔方案决定，其中，C1：101，C2：110，1表示被传输的符号，0表示不被传送的符号。移位寄存器用于存储比特信息，输出的码流序列进入移位寄存器的同时将码流序列分为两个支路，分别进行两路异或运算。第一支路的运算多项式为g1(x)，第二支路的运算多项式为g2(x)。第一支路和第二支路能够将运算结果送入打孔单元，其中，两个支路的运算结果交替进入打孔单元中，打孔单元将连续6比特数据移位划分为一组，每组进入顺序是C 1(1)C 2(1)C 1(2)C 2(2)C 1(3)C 2(3)…。最后打孔单元根据打孔方案将一组数据进行卷积编码3/4删余输出，输出序列的顺序是C 1(1)C 2(1)C 2(2)C 1(3)…。
S4：将卷积编码后产生的数据与载波同步比特、引导序列、独特码、帧尾共同组成完整的调制数据帧。例如，卷积编码后产生的数据可以与320比特载波同步比特、160比特引导序列、64比特独特码、64比特帧尾共同组成完整的调制数据帧。通过将编码方式进行有机组合，形成的组合编码方式的误码率低、保密性高、频谱利用率高。
根据一个可行方式，本发明还可以是一种基于抑制窄带干扰的卫星通信系统。
优选的，窄带卫星1在与地面站2彼此通信时，窄带卫星1也可以接收到由多种组成信号组成的组合信号。组合信号可以包括需求信号和干扰信号，需求信号是指需要通过窄带卫星1进行中继传输的信号。窄带卫星1还包括模数转换模块105、加窗模块106、分离模块107、再生模块108、延迟模块109、消除模块110和反转模块111。窄带卫星1与地面站2之间建立多通道传输，多通道传输的信号彼此之间可以具有频率重叠，进而能够提高频谱资源的利用率。
优选的，窄带卫星1被配置为按照如下方式对具有频率重叠的组合信号进行分离处理：
S1：基于加窗模块106执行加窗处理以获取窗处理信号，并基于干扰检测模块101对所述窗处理信号执行n次幂处理确定组成信号的调制特性及组成信号对应的载波的符号率。
具体的，模数转换模块105用于将窄带卫星接收到的组合信号进行模数转换以将模拟信号转换为数字信号。窄带卫星1接收到的组合信号首先传输至模数转换模块105中进行模数转换处理以生成数字信号。加窗模块106能够接收经模数转换模块105处理生成的数字信号，加窗模块106能够限制数字信号的带宽或者关注数字信号的一部分以保 证其能够对需求信号的频谱部分进行有效处理，进而能够生成窗处理信号。干扰检测模块101可以接收窗处理信号并对其信号组成成分进行识别确定。例如，干扰检测模块101可以配置为将窗处理信号执行n次幂处理直至将其转换为连续波为止。当窗处理信号中包含多种不同信号时，例如可以包含两个需求信号和三个干扰信号，不同的信号由于具有不同的调制特性，进而可以形成多个不同的n次幂处理，即，窗处理信号可能在执行4次幂处理时便可以得到一个连续波，在执行8次幂时又可以得到另一个连续波。具有5种信号的窗处理信号可以以5中不同的n次幂产生5个彼此独立的连续波。n次幂处理按照以2的倍数进行执行，即可以执行2次幂处理、4次幂处理、6次幂处理等。优选的，在执行n次幂处理时，按照每级递增2级的方式进行执行。例如，在执行2次幂处理时未产生连续波的情况下，依次执行4次幂处理、6次幂处理、8次幂处理等。优选的，组成信号的调制特性至少可以通过组成信号的相位偏移、频率偏移、带宽和时间延迟中的一种或多种进行确定。通过n次幂处理后形成的连续波的波形便可以确定相位偏移、频率偏移、带宽和时间延迟。
优选的，可以基于对窗处理信号的n次幂处理过程对窗处理信号的符号率进行确定。例如，当信号在执行n次幂处理的过程中，符号的相位会产生相互关联或将彼此的相互关联关系消除，进而能够形成由频域中的单一频率表示的连续波，该过程能够产生分布在连续波的频率周围的小旁瓣，小旁瓣彼此之间的间隔与相应的组成信号的载波的符号率相关，进而可以基于小旁瓣彼此之间的间隔对载波的符号率进行确定。
S2：在窗处理信号基于n次幂处理产生至少一个连续波的情况下，分离模块107按照基于符号率的m倍的方式对窗处理信号进行重采样以生成重采样信号，并以此确定至少一个符号轨迹和至少一个调制类型。
优选的，当干扰检测模块101确定组合信号中具有多个组成信号时，窗处理信号可以传输至分离模块107中，分离模块可以基于确定的调制特性以符号率的m倍的方式对窗处理信号进行重新采样。即分离模块107是以更高的速率对其接收的信号进行采样，进而能够导出符号轨迹、整形因子和调制类型。整形因子可以用于评价信号能量的集中程度或分散程度。例如，整形因子可以是窗处理信号的根升余弦频谱。优选的，不同组成信号能够在不同的n次幂处理过程中生成多个连续波。例如，在使用二进制相位键控方式对信号进行调制时，可以两次幂处理时产生连续波。在使用正交相移键控方式对信号进行调制时，可以在四次幂处理时产生连续波。因而，可以根据n次幂处理的自乘次数确定信号的调制类型。m的可以是大于2的整数。
优选的，再生模块108基于至少一个符号轨迹和至少一个调制类型对每一个组成信号进行合成以生成合成信号，在确定合成信号是干扰信号的情况下，反转模块111对合成信号进行反转处理以生成反转副本，延迟模块109将数字信号的副本延迟传输至消除模块110中，消除模块110将反转副本与数字信号的副本进行叠加处理以将干扰信号消除，进而能够获得第一级干扰抑制信号。
优选的，如图9所示，第一级干扰抑制信号能够传输至信号预处理模块101中进行处理以将发射信号的时频内容与干扰信号的频率内容进行分离。经信号预处理模块101处理后的第一级干扰抑制信号能够传输至干扰消除模块102中对干扰信号进行进一步消除。
虽然已经详细描述了本发明，但是在本发明的精神和范围内的修改对于本领域技术人员将是显而易见的。这样的修改也被认为是本公开的一部分。鉴于前面的讨论、本领域的相关知识以及上面结合背景讨论的参考或信息(均通过引用并入本文)，进一步的描述被认为是不必要的。此外，应该理解，本发明的各个方面和各个实施方式的各部分均可以整体或部分地组合或互换。而且，本领域的普通技术人员将会理解，前面的描述仅仅是作为示例，并不意图限制本发明。

Claims (15)

  1. 一种窄带多通道卫星通信系统，信号能够经地面站(2)传输至至少一个窄带卫星(1)，若干个地面站(2)彼此之间能够基于所述窄带卫星(1)的中继而彼此通信连接，其特征在于，所述窄带卫星(1)被配置为：
    分别建立第一复正弦曲线和第二复正弦曲线，并确定所述信号的频率成分以对干扰信号的频率内容进行分离；
    基于第一复正弦曲线与所述信号的第一级乘法处理获取第一处理信号并引入载波间干扰；
    按照子载波频率置零的方式消除所述干扰信号以获取第二处理信号；
    在所述第二处理信号经快速傅立叶逆变换处理的情况下，基于第二复正弦曲线与所述第二处理信号的第二级乘法处理消除所述载波间干扰。
  2. 如权利要求1所述的窄带多通道卫星通信系统，其特征在于，所述窄带卫星(1)还被配置为：
    将干扰信号的频率与通信信道的子载波频率中心对准；
    获取与所述干扰信号的频率最接近的快速傅立叶变换滤波器组的频率Δf；
    按照将所述子载波频率所对应的快速傅立叶变换滤波器组的频率Δf置零的方式消除所述干扰信号。
  3. 如权利要求1或2所述的窄带多通道卫星通信系统，其特征在于，所述地面站(2)至少包括编码模块(201)和第一调制模块(202)，所述地面站(2)被配置为按照如下方式对所述信号进行调制处理：
    所述编码模块(201)配置为对所述信号执行编码处理以获取编码信号；
    所述第一调制模块(202)配置为将所述编码信号执行串并变换处理以生成第一支路码流和第二支路码流，其中：
    在所述第一支路码流执行延迟处理以使得所述第一支路码流和所述第二支路码流彼此之间间隔设定码元周期的情况下，所述第一支路码流依次执行第一级滤波处理和第一级调制处理获取第一调制信号，所述第二支路码流依次执行所述第一级滤波处理和第二级调制处理获取第二调制信号；
    所述第一调制信号和所述第二调制信号共同经所述第二级调制处理以获得第三调制 信号，其中，所述第三调制信号经所述第二级滤波处理以完成所述调制处理。
  4. 如权利要求3所述的窄带多通道卫星通信系统，其特征在于，所述编码模块(201)被配置为按照如下方式对所述信号执行编码处理：
    所述信号经BCH编码处理生成的BCH码与发送信息帧共同构成设定比特的若干个信息子帧，所述信息子帧经同步加扰处理以依次执行RS编码处理和卷积编码处理，卷积编码后的数据与载波同步比特、引导序列、独特码、帧尾共同组成完整的调制数据帧，其中：
    在所述信息子帧的比特长度小于设定比特长度的情况下，按照补充零码的方式对其进行补齐。
  5. 如前述权利要求之一所述的窄带多通道卫星通信系统，其特征在于，所述地面站(2)还包括滤波模块(203)、第二调制模块(204)和变频模块(205)，所述地面站(2)还按照如下方式对所述信号进行处理：
    所述编码信号以设定码速率传输至第一调制模块(202)中执行调制处理后以第一载波频率传输至所述滤波模块(203)；
    所述滤波模块(203)配置为对其接收的信号执行滤波处理并传输至所述第二调制模块(204)；
    所述第二调制模块(204)以第二载波频率将其接收的信号传输至所述变频模块(205)，其中，所述变频模块(205)配置为将其接收的信号变频至设定的射频输出频率。
  6. 如前述权利要求之一所述的窄带多通道卫星通信系统，其特征在于，所述窄带卫星(1)至少包括信号调节模块(104)和干扰消除模块(102)，在所述信号经所述地面站(2)传输至所述窄带卫星(1)的情况下，所述窄带卫星(1)配置为按照如下方式对所述信号执行处理：
    将所述信号调节模块(104)配置为：确定所述信号的频率成分并获取若干个不同时频空间的分解信号以将干扰信号的频率内容进行分离；
    将所述干扰消除模块(102)配置为：
    将干扰信号的频率与通信信道的子载波频率中心对准并建立第一复正弦曲线，并基于所述第一复正弦曲线与所述信号的乘法处理以获取偏移信号并以此引入载波间干扰；
    将所述偏移信号依次执行加窗处理和快速傅立叶变换处理以生成频域信号，所述频域信号能够按照子载波频率置零的方式消除所述干扰信号以获取干扰消除信号；
    在所述干扰消除信号经快速傅立叶逆变换处理以产生时域采样样本的情况下，建立第二复正弦曲线并按照所述第二复正弦曲线与所述时域采样样本执行乘法处理的方式消除所述载波间干扰。
  7. 如权利要求6所述的窄带多通道卫星通信系统，其特征在于，所述信号调节模块(104)按照如下步骤获取所述分解信号：
    配置具有若干个不同滤波等级的滤波器组，并且每个滤波等级至少包括低通信道和高通信道，所述低通信道和所述高通信道均配置至少一组离散小波变换器，其中：
    基于所述滤波器组的若干个滤波等级获取若干个不同频段的子带；
    所述子带所包含的信号能够分别经离散小波变换处理分解至若干个不同的时频空间。
  8. 如前述权利要求之一所述的窄带多通道卫星通信系统，其特征在于，所述第一复正弦曲线经公式
    Figure PCTCN2019121951-appb-100001
    限定，所述第二复正弦曲线经公式
    Figure PCTCN2019121951-appb-100002
    限定；
    BCH编码的生成多项式为g(x)＝x 10+x 9+x 8+x 6+x 5+x 3+1；
    RS编码的生成多项式为g(x)＝x 8+x 4+x 3+x 2+1；
    卷积编码的两个输出端口的生成多项式分别为g1(x)＝x 6+x 5+x 4+x 3+1和g2(x)＝x 6+x 4+x 3+x 1+1；
    同步加扰处理的扰码周期和多项式分别为为2 15-1和1+X 14+X 15；
    其中，F s表示采样频率，N是快速傅立叶变换采样点数。
  9. 如前述权利要求之一所述的窄带多通道卫星通信系统，其特征在于，所述第一级滤波处理经第一滤波器(203a)执行，所述第二级滤波处理经第二滤波器(203b)执行，其中：
    所述第一滤波器(203a)是升余弦滚降滤波器，所述第二滤波器(203b)是带通滤波器；所述第一级调制处理是正交调制处理，所述第二级调制处理是同相调制处理。
  10. 如前述权利要求之一所述的窄带多通道卫星通信系统，其特征在于，所述窄带卫星(1)还包括干扰检测模块(101)和解调模块(103)，所述干扰检测模块(101)配置为计算信号的平均功率以确定子带中是否存在干扰信号，所述解调模块(103)配置为对所述干扰消除模块(102)的输出信号进行解调处理。
  11. 如权利要求10所述的窄带多通道卫星通信系统，其特征在于，所述干扰消除模块(102)还被配置为获取与干扰信号的频率最接近的快速傅立叶变换滤波器组的频率Δf，其中：
    所述第一复正弦曲线的频率为Δf，所述第二复正弦曲线的频率为-Δf。
  12. 如权利要求11所述的窄带多通道卫星通信系统，其特征在于，针对所述快速傅立叶变换滤波器组的频率Δf计算过程中所涉及的子载波频率，干扰消除模块(102)能够将该子载波频率所对应的快速傅立叶转换滤波器组频率设置为零以将所述干扰信号消除。
  13. 一种基于抑制窄带干扰的卫星通信系统，窄带卫星(1)与地面站(2)按照多通道的方式彼此通信连接以对具有若干个组成信号的组合信号进行中继传输，其特征在于，
    所述窄带卫星(1)被配置为：
    分别建立第一复正弦曲线和第二复正弦曲线，并确定所述信号的频率成分以对干扰信号的频率内容进行分离；
    基于第一复正弦曲线与所述信号的第一级乘法处理获取第一处理信号并引入载波间干扰；
    按照子载波频率置零的方式消除所述干扰信号以获取第二处理信号；
    在所述第二处理信号经快速傅立叶逆变换处理的情况下，基于第二复正弦曲线与所述第二处理信号的第二级乘法处理消除所述载波间干扰；
    其中，
    所述窄带卫星(1)至少包括干扰检测模块(101)、加窗模块(106)、分离模块(107)和再生模块(108)，在所述组成信号彼此之间具有频率重叠的情况下，所述窄带卫星(1)被配置为按照如下方式对所述组合信号进行处理：
    所述加窗模块(106)配置为基于加窗处理对所述组合信号的频率进行限定后生成窗处理信号；
    所述干扰检测模块(101)配置为基于所述窗处理信号的n次幂处理以确定至少一个组成信号的调制特性及其对应的载波的符号率；
    所述分离模块(107)配置为在所述窗处理信号基于所述n次幂处理产生至少一个连续波的情况下，基于所述符号率的m倍的方式对所述窗处理信号重采样并生成重采样信号，并以此确定至少一个符号轨迹和至少一个调制类型；
    所述再生模块(108)配置为基于所述符号轨迹和所述调制类型对所述组成信号进行合成再生以生成合成信号。
  14. 如权利要求13所述的窄带多通道卫星通信系统，其特征在于，所述窄带卫星(1)还包括消除模块(110)和反转模块(111)，在确定所述合成信号为干扰信号的情 况下，所述窄带卫星(1)被配置为按照如下方式对所述合成信号进行处理：
    所述反转模块(111)配置为对所述合成信号进行反转处理以生成反转副本；
    所述消除模块(110)配置为接收所述组合信号的副本并将所述反转副本和所述组合信号的副本进行叠加处理以生成第一级干扰抑制信号。
  15. 如权利要求13或14所述的卫星通信系统，其特征在于，所述窄带卫星(1)还包括信号预处理模块(104)和干扰消除模块(102)，所述窄带卫星(1)被配置为按照如下方式对所述第一级干扰抑制信号进行处理：
    所述信号预处理模块(104)配置为建立第一复正弦曲线和第二复正弦曲线，并确定所述第一级干扰抑制信号的频率成分以对干扰信号的频率内容进行分离；
    所述干扰消除模块(102)配置为：
    按照所述第一干扰抑制信号与所述第一复正弦曲线的执行乘法处理以生成偏移信号的方式引入载波间干扰；
    按照子载波频率置零的方式获取干扰消除信号并获取其时域采样样本；
    按照所述时域采样样本与所述第二复正弦曲线执行乘法处理的方式消除所述载波间干扰。
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