CN108243130A - Demodulation method, device, spectrum detector and computer readable storage medium - Google Patents
Demodulation method, device, spectrum detector and computer readable storage medium Download PDFInfo
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Abstract
The present invention relates to demodulation method, device, spectrum detector and computer readable storage mediums, belong to signal processing technology field.The demodulation method includes：Receive radio signal；Can modulation system be identified used by judging the radio signal based on presetting method；When to be, the corresponding demodulation mode of modulation system used by can judgement be found with the radio signal；When to be, the radio signal is demodulated based on the demodulation mode.It can carry out effectively identification to the signal of the unknown modulation system of the different frequency range received and search corresponding demodulation mode to go to demodulate by this method, read the useful information carried in the signal, and no longer it is that only known signal is demodulated, greatly solve under current complex electromagnetic environment, it is insufficient to monitoring/monitoring technology of radio the problem of.
Description
Technical Field
The invention belongs to the technical field of signal processing, and particularly relates to a demodulation method, a demodulation device, a frequency spectrum detector and a computer readable storage medium.
Background
Modulation is the process of processing a signal source of information onto a carrier to render it into a form suitable for channel transmission, and is a technique of changing the carrier with the signal source. Generally, information of a signal source (also referred to as a source) contains a direct current component and a frequency component having a lower frequency, and is referred to as a baseband signal. The baseband signal often cannot be used as a transmission signal and must therefore be converted to a signal of very high frequency relative to the baseband frequency to be suitable for channel transmission. This signal is called modulated signal and the baseband signal is called modulated signal. The modulation is achieved by changing the amplitude, phase or frequency of the high frequency carrier, i.e. the carrier signal of the message, so that it varies with the amplitude of the baseband signal. Demodulation is the process of extracting the baseband signal from the carrier for processing and understanding by the intended recipient (also known as the sink).
In other words, both sides predetermine the modulation type in advance and know the demodulation method accordingly, the transmitting side modulates the signal according to the predetermined convention when transmitting the signal, and the receiving side demodulates the signal based on the known demodulation method after receiving the signal.
Disclosure of Invention
In view of the above, the present invention provides a demodulation method, a demodulation apparatus, a spectrum detector and a computer readable storage medium, so as to effectively solve the problem of insufficient monitoring/monitoring techniques for radio in the current complex electromagnetic environment.
The embodiment of the invention is realized by the following steps:
in a first aspect, an embodiment of the present invention provides a demodulation method, including: receiving a radio signal; judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method; if so, judging whether a demodulation mode corresponding to the modulation mode adopted by the radio signal can be found; if so, the radio signal is demodulated based on the demodulation method.
In a second aspect, an embodiment of the present invention further provides a demodulation apparatus, including: a receiving module for receiving a radio signal; the first judgment module is used for judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method; a second judgment module, configured to judge whether a demodulation mode corresponding to the modulation mode used by the radio signal can be found; and the selection module is used for demodulating the radio signal based on the demodulation mode.
In a third aspect, an embodiment of the present invention further provides a spectrum detector, including: a processor and a memory, the processor coupled with the memory; the memory is used for storing programs; the processor is used for calling a program stored in the memory and executing the demodulation method.
In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium storing program code executable by a processor in a computer, the computer-readable storage medium including a plurality of instructions configured to cause the processor to execute the demodulation method.
Compared with the prior art, the demodulation method, the demodulation device, the spectrum detector and the computer readable storage medium provided by the embodiment of the invention greatly solve the problem of insufficient radio monitoring/monitoring technology in the current complex electromagnetic environment. Further, in the radio spectrum monitoring and information countermeasure under the non-cooperative communication condition, the non-cooperative receiving party cannot predict the modulation mode used by the received radio signal, therefore, when the radio signal is received, whether the modulation mode of the signal can be identified is judged based on a preset method, if so, whether a demodulation mode matched with the modulation mode can be found is judged, and if so, the demodulation mode is selected to demodulate so as to read the useful information carried in the signal, and the demodulation is not carried out on the known signal.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts. The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings. Like reference numerals refer to like parts throughout the drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
Fig. 1 shows a block diagram of a spectrum detector according to an embodiment of the present invention.
Fig. 2 shows a flowchart of a demodulation method according to a first embodiment of the present invention.
Fig. 3 shows a flowchart of a method of step S102 in fig. 2 according to an embodiment of the present invention.
Fig. 4 shows a flowchart of a demodulation method according to a second embodiment of the present invention.
Fig. 5 shows a block diagram of a demodulation apparatus according to a third embodiment of the present invention.
Fig. 6 is a block diagram illustrating a second determining module in fig. 5 according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "first", "second", "third", and the like are used only for distinguishing the description, and are not intended to indicate or imply relative importance.
As shown in fig. 1, fig. 1 is a block diagram illustrating a spectrum detector 100 according to an embodiment of the present invention. The spectrum sensor 100 includes: demodulation apparatus 110, memory 120, memory controller 130, and processor 140.
The memory 120, the memory controller 130, and the processor 140 are electrically connected to each other directly or indirectly to realize data transmission or interaction. For example, the components may be electrically connected to each other via one or more communication buses or signal lines. The demodulation device 110 includes at least one software functional module, which may be stored in the memory 120 in the form of software or firmware (firmware) or solidified in an Operating System (OS) of the spectrum detector 100. The processor 140 is configured to execute executable modules stored in the memory 120, such as software functional modules or computer programs included in the demodulation apparatus 110.
The Memory 120 may be, but is not limited to, a Random Access Memory (RAM), a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Read-Only Memory (EPROM), an electrically Erasable Read-Only Memory (EEPROM), and the like. The memory 120 is used for storing a program, and the processor 140 executes the program after receiving an execution instruction, and a method executed by the spectrum detector 100 defined by a process disclosed in any embodiment of the invention described later may be applied to the processor 140, or implemented by the processor 140.
The processor 140 may be an integrated circuit chip having signal processing capabilities. The processor may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. The various methods, steps and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
First embodiment
Referring to fig. 2, steps included in a demodulation method applied to the spectrum detector 100 according to an embodiment of the present invention will be described with reference to fig. 2.
Step S101: a radio signal is received.
The spectrum detector receives the detected radio signal when detecting the radio signal.
Step S102: and judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method.
After receiving a radio signal, in order to further know the content contained in the signal, the received signal needs to be demodulated first, because the received radio signal is not a signal modulated according to a predetermined modulation method, but is an unknown signal. Therefore, it is necessary to determine whether or not the modulation scheme used for the radio signal can be identified. This step is further illustrated by the method flow diagram shown in fig. 3.
Step S201: and preprocessing the radio signal to obtain a preprocessed signal.
Because the current modulation signal can be divided into an analog modulation signal and a digital modulation signal according to the form, if the radio signal is the digital modulation signal, the radio signal can be directly sampled to obtain a sampling signal, and if the radio signal is the analog modulation signal, the radio signal needs to be subjected to AD conversion to obtain a digital signal, and then the digital signal is sampled to obtain the sampling signal. I.e. the above-mentioned preprocessing differs depending on the received signal, i.e. the preprocessing is AD conversion and/or sampling.
Step S202: and extracting characteristic quantity representing the modulation mode based on the preprocessed signal.
Extracting a characteristic quantity of the pre-processed signal after AD conversion and/or sampling, wherein the characteristic quantity can be any characteristic quantity capable of characterizing a modulation mode, such as: cumulative-based classification features, spectral-based classification features, amplitude envelope flatness-based classification features, and the like.
Step S203: and judging whether the characteristic quantity can be identified based on a preset method.
And after the characteristic quantity of the signal is obtained, selecting a method from a method database to identify the modulation mode corresponding to the characteristic quantity, and if the method cannot identify the modulation mode corresponding to the characteristic quantity, selecting a method from the rest methods to identify the modulation mode corresponding to the characteristic quantity until the modulation mode corresponding to the characteristic quantity is identified or all the methods in the method database are selected. The preset method may be a Radial Basis Function Neural Network (RBFNN) or a signal matching identification algorithm based on a communication characteristic parameter.
The signal matching identification algorithm based on the communication characteristic parameters is used for accurately and quickly identifying the modulation mode of the radio by using the detection signal frequency index S, Chirp signal characteristic index P and the spectrum peak index T. Due to the fact that the characteristic parameters corresponding to different modulation modes are different, the type of signals meeting the parameter specification can be rapidly identified by the aid of the three characteristic parameters.
When it is determined whether the feature quantity can be recognized based on a preset method, if the feature quantity can be recognized, step S103 is executed, and if the feature quantity cannot be recognized, the process is terminated.
Step S103: and judging whether a demodulation mode corresponding to the modulation mode adopted by the radio signal can be found.
When the modulation scheme of the radio signal is identified, for example, FSK, MFSK, PSK, BPSK, QPSK, 8PSK, DBPSK, DQPSK, 8DPSK, 16DPSK, MPSK, BPSM, QPSM, 8PSM, QAM16, QAM32, QAM64, and the like are used. And judging whether a demodulation mode corresponding to the modulation mode can be found. If the demodulation mode corresponding to the signal can not be found, ending the process; if the corresponding demodulation method can be found, step S104 is executed.
Step S104: the radio signal is demodulated based on the demodulation method.
When a demodulation method corresponding to the modulation method adopted by the radio signal can be found, the signal is demodulated based on the found demodulation method to obtain a demodulated signal, so that the subsequent processing can be carried out. Furthermore, since the modulation signal can adopt a parallel burst mode to transmit information, after a target signal is identified, burst capture is required to be carried out, the start-stop position of a burst is accurately positioned, and burst signal positioning under the condition of low signal-to-noise ratio is effectively realized by adopting a burst detection algorithm based on spectral entropy. The basic principle of the algorithm is as follows: the observation number x (n) is set to contain L sampling points, and the L sampling points are segmented. Each segment is assumed to contain N sampling pointsA section whereinIndicating a rounding down. Writing the observed data x (n) in matrix form, i.e.
The observed data is then subjected to Short-time fourier transform (STFT), i.e.:
where k is 0,1, …, and N-1 indicates the frequency bin of the STFT. w (N) is a sliding window of length N. h represents the number of samples spaced between two adjacent windows. Xk(m) may beTo represent the following form:
wherein, | Xk(m) andrepresenting the magnitude and phase spectra, respectively.
From the statistical characteristics of signal and noise amplitude spectrum, firstly, the method is used for | Xk(m)|2Defining a normalized spectral probability density function for each frequency component;
wherein p iskIs the probability density for a certain frequency component k. Since the burst signal is typically sine wave modulated, it has a repetitive harmonic structure in the spectrum, and noise does not have this characteristic, so the Entropy (Entropy) of the spectrum can be used for detection. Similar to speech signal processing, the spectral entropy of the form:
entropy H (m) represents | Xk(m)2When the observed data x (n) is white noise, the probability of each frequency component of x (n) is equal, the uncertainty is maximum, and the entropy is maximum; when the observed data is a burst signal, the samples have larger correlation, the uncertainty is smaller, and the entropy value is smaller. This indicates | Xk(m)|2The more fuzzy the probability distribution of (a) is, the larger the entropy value is. Let H be a row vector consisting of spectral entropies of each piece of observed data, i.e., H ═ H (1), H (2), …, H (M)]Comparing H with a preset threshold, if smallAnd considering the burst signal to start to appear at the threshold value until the spectrum entropy is larger than the threshold value, and considering the signal to end.
Wherein the selection of the threshold will directly affect the detection performance of the algorithm. Compared with a fixed threshold, the adaptive threshold detection algorithm can adaptively adjust the threshold value according to the time-varying characteristic of the signal. The decision threshold γ is defined as:
where N represents the data window length and α is a scaling factor related to the false alarm probability, when the constant false alarm probability is pFAWhen there is
After burst positioning is carried out by using a spectral entropy method, burst synchronization head information can be further used for carrying out time domain correlation on a synchronization head and observation data, and the burst signal effective positioning under a low signal-to-noise ratio can be realized by combining the synchronization head and the observation data.
In which the influence of short-wave channel fading characteristics on signal transmission (additive noise and multiplicative interference) is taken into account, wherein multiplicative interference includes frequency selective fading caused by multipath effect and non-linear time selective fading caused by inter-path doppler difference effect. Therefore, a multi-strategy joint anti-fading non-partner blind receiving algorithm can be adopted to acquire the channel parameters required during demodulation. The multi-strategy joint anti-fading non-partner blind receiving algorithm comprises the following steps: symbol rate estimation based on the squared spectrum of the signal envelope, non-data aided carrier frequency offset maximum likelihood estimation and non-data aided carrier initial phase estimation.
For short wave signals with low signal-to-noise ratio under non-cooperative blind receiving conditions, a non-data-aided forward estimation algorithm can be adopted when carrier synchronization parameters (carrier frequency and carrier phase) are estimated, namely parameters are directly estimated from samples of received signals based on a certain criterion (for example, a maximum likelihood criterion). For signal capture and identification under the condition of blind reception of a non-partner, firstly, carrying out coarse estimation on carrier frequency offset based on a detection signal to realize rapid capture of a carrier, and limiting an estimation error within +/-0.5 Hz; then carrying out down-conversion and matched filtering processing; and then, carrying out fine estimation on symbol rate, carrier frequency offset and carrier phase aiming at each path of subcarrier to obtain the demodulation information bit stream of each path.
Considering that the influence of fading on the short-wave burst signal is random, fading may occur at the head of the burst, or may occur in the middle or at the tail of the burst. At this time, if the demodulation parameters are estimated in a single manner (for example, demodulation parameter estimation is performed using burst header data all together), the result is likely to be inaccurate. Aiming at the problem, a multi-strategy joint anti-fading non-cooperative blind receiving algorithm which starts from different positions of burst signals, respectively carries out demodulation processing and then carries out fusion judgment on the result is adopted, and the optimal demodulation result is determined by respectively utilizing the data of the head, the middle and the tail of the burst to estimate the demodulation parameters and combining the CRC check result. Further, regarding a certain burst signal of a certain path of sub-carrier, dividing the burst into a head part, a middle part and a tail part for consideration, respectively performing demodulation parameter estimation, and determining whether the data frame is correctly demodulated through CRC check. By using the strategy, the influence of the short-wave channel fading characteristic on signal blind reception can be effectively reduced.
1) Symbol rate estimation based on the squared spectrum of the signal envelope:
in this case, the received signal symbol rate is deviated from the theoretical value in consideration of a certain error in the crystal oscillators of both the communication parties. This requires symbol rate estimation prior to symbol timing estimation, using a symbol rate estimation algorithm based on the squared spectrum of the signal envelope.
For observed data x (t) in white gaussian noise w (t), the following:
wherein, anAnd bnRepresenting the real and imaginary parts, T, of the information symbolbIs a symbol period, fcIs the carrier frequency. Firstly, Hilbert conversion is carried out to obtain an analytic signalThen calculateThe squared envelope signal z (t), i.e.:
by appropriate derivation, one can obtain:
wherein,and the Fourier transform of u (t) can be expressed as
Thus, the discrete spectral lines corresponding to the symbol rate can be detected from the fourier transform magnitude spectrum of z (t).
2) Non-data-aided maximum likelihood estimation:
and carrying out fine estimation on the carrier frequency offset of the quasi-baseband signal subjected to the rough frequency offset estimation, the down-conversion and the matched filtering by adopting a non-data-aided maximum likelihood estimation algorithm.
Assume that the received data for which accurate symbol synchronization has been obtained is:
wherein, akIs the independent and equally distributed equivalent DQPSK data (assuming that the signal is a 16-tone signal adopting DQPSK modulation mode), T is the symbol period, feIs the unknown carrier frequency offset, θ0Is the unknown carrier phase, nkIs complex white Gaussian noise with the variance of sigma2. By proper derivation, x can be knownkThe log-likelihood function of (a) is:
where N represents the data symbol length and has:
wherein,represents a pair function Y (a)k…) of akAnd taking an average value. By substituting equation (2) for equation (1) and omitting irrelevant terms, we can obtain:
for a 2 pi/M rotationally symmetric constellation, we can further simplify to:
thereby obtaining the maximum likelihood estimation of the carrier frequency offset as:
then order:
for the derivation of the above equation, only the necessary condition that the derivative is 0, i.e. the imaginary part is 0, is analyzed, i.e.:
wherein the autocorrelation function r (k) is defined as:
and is provided withIt can be seen that the autocorrelation function r (k) contains all the information of the carrier frequency offset, and then the classical M is used&The M algorithm estimates the frequency offset, i.e.:
wherein the weight w (k) is:
3) non-data-aided carrier initial phase estimation:
if the burst time is short, it is sufficient to perform phase estimation once in a burst time, but if the burst time is long, it is not reasonable to assume that there is no frequency offset in a burst time, and at this time, the whole burst needs to be divided into several time periods, and it is assumed that there is no frequency offset in each period, and phase offset estimation is performed for each segment of data. This processing method may generate phase jumps from segment to segment, i.e., phase ambiguity from segment to segment.
To solve this problem, a carrier phase estimation value is obtained based on a V & V algorithm. The implementation process of the V & V algorithm can be summarized as follows: nonlinear de-modulation transforms-sum of the real and imaginary signals, respectively-compute phase. If the burst is short, the value is considered as the carrier phase estimation result of the burst; if the burst is longer, it is determined whether there is a phase jump and the phase jump is further eliminated.
Let V&The phase estimation value of the ith section of data output by the V algorithm isThe value range is + -pi/M, M represents the modulation order of DQPSK signal, and the actual phase isOne of them. Suppose the actual phase of the i-1 th segment signal within a burst is:
then, the actual phase of the i-th segment signal:
must be the closestThe phase value of (a), i.e.:
by adopting the method, the probability of continuous phase jump can be effectively reduced, and the anti-noise performance of the algorithm is improved.
Second embodiment
As an implementation manner, referring to fig. 4, the present embodiment provides a demodulation method applied to the spectrum detector 100, and the steps included in the demodulation method will be described with reference to fig. 4.
Step S301: a radio signal is received.
The step is the same as step S101, and please refer to step S101 for details.
Step S302: and judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method.
The step is the same as step S102, and please refer to step S102 specifically, wherein, if the modulation scheme adopted by the radio signal cannot be identified, step S305 is executed.
Step S303: and judging whether a demodulation mode corresponding to the modulation mode adopted by the radio signal can be found.
The step is the same as step S103, and please refer to step S103 for further description.
Step S304: the radio signal is demodulated based on the demodulation method.
The step is the same as step S104, and please refer to step S104 for specific description.
Step S305: and recording or sampling and storing the radio signal.
When the modulation mode adopted by the radio signal cannot be identified, the radio signal is recorded or sampled and stored to serve as a subsequent signal modulation analysis material, so that a new identification mode is developed for identifying the radio signal.
Third embodiment
The embodiment of the invention also provides a demodulation device, as shown in fig. 5. The demodulation apparatus 110 includes: the device comprises a receiving module 111, a first judging module 112, a second judging module 113, a selecting module 114 and a storing module 115.
The receiving module 111 is configured to receive a radio signal.
A first determining module 112, configured to determine whether the modulation scheme adopted by the radio signal can be identified based on a preset method. Further, as shown in fig. 6, the first determining module 112 further includes: a preprocessing submodule 1121, a feature extraction submodule 1122 and a judgment submodule 1123.
The preprocessing submodule 1121 is configured to preprocess the radio signal to obtain a preprocessed signal.
And a feature extraction submodule 1122, configured to extract a feature quantity characterizing the modulation scheme based on the preprocessed signal.
A judgment sub-module 1123 configured to judge whether the feature amount can be identified based on a preset method.
A second determining module 113, configured to determine whether a demodulation method corresponding to the modulation method used by the radio signal can be found.
A selecting module 114, configured to demodulate the radio signal based on the demodulation manner.
And the storage module 115 is configured to record or sample and store the radio signal.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
The implementation principle and the technical effect of the demodulation apparatus 110 provided by the embodiment of the present invention are the same as those of the foregoing method embodiments, and for the sake of brief description, reference may be made to the corresponding contents in the foregoing method embodiments for the part of the embodiment that is not mentioned.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, the functional modules in the embodiments of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a notebook computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes. It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A demodulation method, comprising:
receiving a radio signal;
judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method;
if so, judging whether a demodulation mode corresponding to the modulation mode adopted by the radio signal can be found;
if so, the radio signal is demodulated based on the demodulation method.
2. The method of claim 1, wherein determining whether the modulation scheme used by the radio signal is recognizable based on a predetermined method comprises:
preprocessing the radio signal to obtain a preprocessed signal;
extracting characteristic quantity representing a modulation mode based on the preprocessed signal;
and judging whether the characteristic quantity can be identified based on a preset method.
3. The method according to claim 2, wherein determining whether the feature quantity can be recognized based on a preset method includes:
and judging whether the characteristic quantity can be identified based on a radial basis function neural network or a signal matching identification algorithm based on the communication characteristic parameters.
4. The method of claim 1, wherein when the modulation scheme employed by the radio signal cannot be identified, the method further comprises:
and recording or sampling and storing the radio signal.
5. A demodulation apparatus, comprising:
a receiving module for receiving a radio signal;
the first judgment module is used for judging whether the modulation mode adopted by the radio signal can be identified or not based on a preset method;
a second judgment module, configured to judge whether a demodulation mode corresponding to the modulation mode used by the radio signal can be found;
and the selection module is used for demodulating the radio signal based on the demodulation mode.
6. The demodulation apparatus according to claim 5, wherein the first determining module comprises:
the preprocessing submodule is used for preprocessing the radio signal to obtain a preprocessed signal;
the characteristic extraction module is used for extracting characteristic quantity representing a modulation mode based on the preprocessed signal;
and the judging submodule is used for judging whether the characteristic quantity can be identified based on a preset method.
7. The demodulation apparatus according to claim 6, wherein the determining sub-module is further configured to determine whether the feature quantity can be identified based on a radial basis function neural network or a signal matching identification algorithm based on a communication feature parameter.
8. The demodulation apparatus according to claim 5, wherein said demodulation apparatus further comprises: and the storage module is used for recording or sampling and storing the radio signal.
9. A spectrum detector, comprising: a processor and a memory, the processor coupled with the memory;
the memory is used for storing programs;
the processor is used for calling a program stored in the memory and executing the demodulation method of any one of claims 1-4.
10. A computer-readable storage medium storing program code executable by a processor in a computer, the computer-readable storage medium comprising instructions configured to cause the processor to perform the demodulation method of any one of claims 1 to 4.
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