CN112202698B - Method and device for noncoherent demodulation and detection of heartbeat control packet and electronic equipment - Google Patents
Method and device for noncoherent demodulation and detection of heartbeat control packet and electronic equipment Download PDFInfo
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Abstract
The invention discloses a method, a device and electronic equipment for noncoherent demodulation and detection of a heartbeat control packet, wherein the method comprises the following steps: acquiring a data packet to be detected; performing incoherent demodulation on the acquired data packet to be detected to obtain M FSK incoherent demodulation results; judging according to the size relation between the incoherent demodulation result and the judgment threshold value to obtain a judgment symbol result or a transition symbol 'z', and calculating soft information S of a corresponding symbol; calculating the sum of soft information S corresponding to the M symbols, and generating a pre-synchronization signal when the sum is not less than a set threshold value T, the M judgment results are compared with known heartbeat control packet code words without error codes, and a transition symbol 'z' does not enter the error codes, or else, generating no pre-synchronization signal; and performing signal demodulation and detection once every effective sampling length L, and judging that the heartbeat control packet is detected when p or more pre-synchronization signals are continuously generated. The invention has the advantages of low false alarm probability, no influence of strong interference at the anti-communication frequency point and the like.
Description
Technical Field
The invention belongs to the technical field of signal detection and processing, and particularly relates to a method and a device for noncoherent demodulation and detection of a heartbeat control packet and electronic equipment.
Background
The heartbeat control packet is a control data packet with a size of M symbols sent by a sending end to a receiving end (the receiving end can comprise a plurality of nodes) at intervals among interconnected equipment, and when the receiving end equipment cannot detect the heartbeat control packet of the sending end, the communication is considered to be interrupted, and then the equipment directly makes corresponding action or feeds an interruption result back to the sending end equipment.
Frequency Shift Keying (FSK) is a common modulation scheme in communications and is based primarily on controlling the frequency of a carrier wave in which digital information is transmitted, such as the carrier frequency f in 2FSK0Corresponding bit information "0", and carrier frequency f1Symbol information in FSK corresponding to bit information '1' or 4 respectively with carrier frequency f0、f1、f2、f3And (4) showing. As shown in fig. 2, each symbol data of the heartbeat control packet is used as a baseband signal, the baseband signal is modulated by using a 4FSK method, the baseband signal is modulated to a higher frequency band, the heartbeat control packet is converted into an analog signal, the analog signal is amplified by power and then can be transmitted in a long distance in a channel, and adjacent heartbeat control packets are separated by a time slot with a certain length.
Taking 4FSK heartbeat control packets as an example, a common incoherent demodulation process is shown in fig. 3, where a received original signal is processed by an analog channel, a/D converted and then sampled into a digital signal r (N), divided into eight paths, multiplied by sine and cosine signals corresponding to demodulation frequencies, and g is a signal waveform window function (such as a rectangular window, a hanning window, a gaussian window, etc.) with a length of NN(nTs) And respectively intercepting partial information of corresponding symbol positions (N corresponds to the sampling length of 1 FSK symbol), calculating the square sum of the summation results of the same path, then comparing the square sum, and taking the symbol corresponding to the maximum value as the current decision result.
Other FSK noncoherent demodulation modes are similar to the 4FSK, and demodulation judgment can be carried out after branches are correspondingly subtracted or added.
The detection of the traditional heartbeat control packet generally receives signals from a channel in a serial mode at a receiving end according to a hard decision result of a whole control data frame packet, data signals with the size of M × N are obtained after the processing of modules such as sampling, filtering and the like, signals are intercepted by M connected and non-overlapped signal waveform window functions and are respectively subjected to incoherent demodulation to obtain M times of hard decision results, a pre-synchronization signal is generated if the data are completely consistent with known heartbeat control packet data, a plurality of pre-synchronization signals are continuously detected to judge and detect the heartbeat control packet, the principle is shown in figure 4, and the pre-synchronization signal can be generated if a starting point of data to be detected is positioned near an optimal detection position.
In the noncoherent demodulation of FSK, the possible interferences occurring in the channel can be classified into single-frequency interference at or near the carrier frequency, single-frequency interference at non-carrier frequency, simultaneous existence of multiple single-frequency interferences, narrowband interference and wideband interference, etc. Since the incoherent demodulation of the FSK signal only concerns the demodulation result at the carrier frequency position, and the filter of the signal channel at the receiving end can also well filter the interference far away from the carrier frequency, the strong interference is mainly expressed as the direct interference at the carrier frequency and the interference of the frequency interference near the carrier frequency to the carrier frequency due to the leakage of the spectrum energy thereof.
For a traditional FSK noncoherent demodulation communication system, when interference higher than the strength of a normal heartbeat control packet occurs at a certain communication frequency point (carrier frequency position), a filter of the system cannot filter the interference at the communication frequency point, at the moment, a sending end sends the heartbeat control packet, the noncoherent demodulation result of a receiving end at a frequency point corresponding to strong interference is always higher than the values of other frequency points, the judgment result is also fixed to a certain symbol, if the sent information is the symbol, the judgment is not wrong, if other symbol information is sent, the judgment result is still the symbol corresponding to the interference frequency, the heartbeat control packet with the length of M symbols is wrong, a pre-synchronization signal cannot be accurately generated, and the noncoherent demodulation and detection of the FSK modulated heartbeat control packet fail.
In summary, the conventional incoherent demodulation and detection system for the heartbeat control packet has a certain disadvantage in the face of strong interference, and the judgment result of the receiving end is constantly the symbol information corresponding to the interference frequency during demodulation, so that the demodulation and detection system for the heartbeat control packet fails and cannot continue to work normally.
Disclosure of Invention
The embodiment of the invention aims to provide a method, a device and electronic equipment for noncoherent demodulation and detection of a heartbeat control packet, so as to solve the problem that a heartbeat control packet control system cannot continue to work normally when the position of a channel communication frequency point in the traditional technology has interference which is not less than the amplitude of the heartbeat control packet.
In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:
in a first aspect, an embodiment of the present invention provides a method for noncoherently demodulating and detecting a heartbeat control packet, including:
an acquisition step, which is used for acquiring a data packet to be detected;
an incoherent demodulation step, which is used for carrying out incoherent demodulation on the acquired data packet to be detected to obtain M FSK incoherent demodulation results;
a decision step, which is used for carrying out decision according to the size relation between the incoherent demodulation result and the decision threshold value to obtain a decision symbol result or a transition symbol 'z' and calculating soft information S of a corresponding symbol;
a pre-synchronization signal generation step, which is used for calculating the sum of soft information S corresponding to M symbols, and when the sum is not less than a set threshold value T, and M judgment results are compared with known heartbeat control packet code words without error codes, a pre-synchronization signal is generated when a transition symbol 'z' does not count the error codes, otherwise, the pre-synchronization signal is not generated;
and a demodulation and detection step, which is used for carrying out signal demodulation and detection once every effective sampling length L and judging that the heartbeat control packet is detected when p or more presynchronization signals are continuously generated.
In a second aspect, an embodiment of the present invention further provides an apparatus for noncoherently demodulating and detecting a heartbeat control packet, where the apparatus includes:
the acquisition module is used for acquiring a data packet to be detected;
the noncoherent demodulation module is used for performing noncoherent demodulation on the acquired data packet to be detected to obtain M FSK noncoherent demodulation results;
the decision module is used for carrying out decision according to the size relation between the incoherent demodulation result and the decision threshold value to obtain a decision symbol result or a transition symbol 'z' and calculating soft information S of a corresponding symbol;
the pre-synchronization signal generation module is used for calculating the sum of the soft information S corresponding to the M symbols, and when the sum is not less than a set threshold value T, and M judgment results are compared with known heartbeat control packet code words without error codes, a pre-synchronization signal is generated when a transition symbol 'z' does not count the error codes, otherwise, the pre-synchronization signal is not generated;
and the demodulation and detection module is used for demodulating and detecting signals once every effective sampling length L and judging that the heartbeat control packet is detected when more than p pre-synchronization signals are continuously generated.
In a third aspect, an embodiment of the present invention further provides an electronic device, including:
one or more processors;
a memory for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement a method as described in the first aspect.
According to the technical scheme, the beneficial technical effects of the invention are as follows: the effects brought by the scheme of claim 1
(1) According to the incoherent demodulation and detection method of the FSK heartbeat control packet, when the heartbeat control packet is sent, strong interference occurs at a certain carrier frequency of a channel, a receiving end judges whether the heartbeat control packet and the interference exist at the same time according to a judgment threshold value, judges the heartbeat control packet and the interference as transition symbol information which does not cause error codes, and avoids the phenomenon that strong interference directly causes the demodulation and detection system of the heartbeat control packet to be incapable of working normally. The decision threshold value is iteratively adjusted in the idle time slot of each heartbeat control packet, channel change is self-adapted, and a transition symbol mechanism is started on the premise of accurately identifying interference.
(2) In order to inhibit the generation of signal false alarm, the invention adopts a mode of jointly controlling the generation of the pre-synchronization signal by the transition symbol and the soft information sum, counts the soft information sum of the M symbols in order to avoid the problem of signal false alarm introduced by the transition symbol, and can not generate the pre-synchronization signal even if the soft information sum does not meet the requirement of a threshold value T. The threshold value setting of the soft information sum ensures that the receiving device does not generate the presynchronization signal by mistake due to the judgment of excessive transition symbols under the condition of no heartbeat control packet.
(3) Compared with other methods for incoherent demodulation and detection of the FSK modulated heartbeat control packet, the method has the advantages of low false alarm probability, effective resistance to strong interference near a communication frequency point and the like, and both simulation and actual systems prove that the incoherent demodulation and detection system of the FSK modulated heartbeat control packet can still work normally under a channel with strong interference at the communication frequency point, so that the stability of the system controlled by the heartbeat control packet is further improved.
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The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flowchart of a method for noncoherent demodulation and detection of a heartbeat control packet according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a 4FSK modulated heartbeat control packet from baseband to modulation waveform;
fig. 3 is a schematic structural diagram of a commonly used FSK modulated heartbeat control packet non-coherent demodulation and detection method in the conventional art;
fig. 4 is a schematic diagram illustrating a detection principle of a heartbeat control packet with a conventional FSK modulation;
FIG. 5 is a schematic structural diagram of a method for noncoherent demodulation and detection of a heartbeat control packet to which the present invention is applied;
FIG. 6 is f0Outputting a diagram of a presynchronization signal by a traditional FSK modulated heartbeat control packet incoherent demodulation and detection method when 1-time signal amplitude interference occurs at a position;
FIG. 7 is f0When the position has 1 time signal amplitude interference, the method for noncoherently demodulating and detecting the heartbeat control packet outputs a diagram of presynchronization signals;
fig. 8 is a block diagram of an apparatus for noncoherent demodulation and detection of a heartbeat control packet according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. 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 application.
Example 1:
aiming at the problem that a heartbeat control packet control system cannot continue to work normally when the interference which is not smaller than the amplitude of a heartbeat control packet occurs at the position of a channel communication frequency point in the traditional technology, the embodiment of the invention provides a method for incoherent demodulation and detection of the heartbeat control packet, the embodiment takes incoherent demodulation and detection of the heartbeat control packet modulated by 4FSK as an example to elaborate the scheme provided by the application in detail, certainly not only limited to incoherent demodulation and detection of the heartbeat control packet modulated by 4FSK, but also comprises the following steps:
an acquisition step S101, acquiring a data packet to be detected;
specifically, the receiving device obtains a data packet to be detected with a length of M × N from the channel, where N corresponds to a sampling length of 1 FSK symbol, and M is the number of symbols of the heartbeat control packet.
An incoherent demodulation step S102, which is to perform incoherent demodulation on the acquired data packet to be detected to obtain M FSK incoherent demodulation results; the method specifically comprises the following steps:
step S1021, intercepting the acquired heartbeat control packet by using signal waveform window functions with M FSK signal lengths to obtain receiving data corresponding to M symbols; signal waveform window function (e.g., rectangular window, Hanning window, Gaussian window, etc.) gN(nTs) The length is N, the corresponding symbol position parts are respectively intercepted by M identical waveform windows which are connected and do not overlap, the received data corresponding to M symbols is obtained, the symbols can be ensured not to interfere with each other through the waveform windows, and meanwhile, the main lobe width of a signal frequency spectrum is reduced.
Step S1022, setting an incoherent demodulation frequency; the demodulation frequency is used for FSK modulation of the heartbeat control packet; 4FSK modulation frequency of f0、f1、f2、f3For use in the demodulation process.
Step S1023, dividing the received data corresponding to each symbol into multiple paths, and multiplying the multiple paths by a sine signal and a cosine signal corresponding to demodulation frequency respectively; corresponding each symbol after windowing to the received data and the demodulation signal cos (2 pi f)0nTs)、sin(2πf0nTs)、cos(2πf1nTs)、sin(2πf1nTs)、cos(2πf2nTs)、sin(2πf2nTs)、cos(2πf3nTs)、sin(2πf3nTs) Multiplication, n denotes the nth sampling instant, f0、f1、f2、f3Modulating frequency, T, by FSKsRepresenting the sampling interval.
And step S1024, summing the signals of each path, and calculating the sum of squares of the summation results of the same demodulation frequency to obtain the incoherent demodulation results of the frequency points corresponding to the M symbols. Summing each path of signal to obtain r0c、r0s、r1c、r1s、r2c、r2s、r3c、r3sThe calculation expression is as follows:
calculating r0cAnd r0s、r1cAnd r1s、r2cAnd r2s、r3cAnd r3sSum of squares v of0 2、v1 2、v2 2、v3 2The calculation expression is as follows:
the incoherent demodulation result can be regarded as the signal energy size at the corresponding carrier frequency, and is used as a judgment basis.
A decision step S103, which is to perform decision according to the size relationship between the incoherent demodulation result and the decision threshold value to obtain a decision symbol result or a transition symbol "z", and calculate soft information S of a corresponding symbol; the method comprises the following steps:
step S1031, except the maximum incoherent demodulation result, under the condition that other demodulation results are all smaller than a decision threshold value, the decision result is the symbol corresponding to the maximum incoherent demodulation result; the incoherent demodulation result of the non-decision frequency point is lower, and the non-coherent demodulation result is not greater than the decision threshold value B0 u、B1 u、B2 u、B3 uIn the case (u is the current iteration number), it is considered that the channel does not have strong interference at the carrier frequency, and a conventional FSK noncoherent demodulation decision method is adopted, and the decision process is as follows:
v0 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is1 2≤B1 u、v2 2≤B2 u、v3 2≤B3 uThe decision result J is the symbol "0";
v1 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2≤B0 u、v2 2≤B2 u、v3 2≤B3 uThe decision result J is the symbol "1";
v2 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2≤B0 u、v1 2≤B1 u、v3 2≤B3 uThe decision result J is the symbol "2";
v3 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2≤B0 u、v1 2≤B1 u、v2 2≤B2 uThe decision result J is the symbol "3";
the decision formula for the current symbol J is as follows:
and judging that no strong interference exists at the carrier frequency of the channel under the condition that the non-coherent demodulation result of the non-decision frequency point does not exceed the decision threshold value, thereby avoiding the condition of false alarm caused by starting a transition symbol mechanism.
Step S1032, divide the maximum incoherent demodulation resultBesides, under the condition that other demodulation results are not less than the decision threshold, the two cases are divided at this time: when the maximum value is larger than k times of the mean value of other demodulation results, the judgment result is the symbol corresponding to the maximum incoherent demodulation result; when the maximum value is less than or equal to k times of the average value of other demodulation results, the decision result is the transition symbol 'z'. The incoherent demodulation result of the non-decision frequency point is higher and is more than the decision threshold value B0 u、B1 u、B2 u、B3 uIn the case (u is the current iteration number), it is considered that strong interference may exist at the communication frequency point in the channel at this time, and a transition symbol decision mechanism is introduced at this time, when max (v) is reached0 2,v1 2,v2 2,v3 2) In (v)0 2+v1 2+v2 2+v3 2-max(v0 2,v1 2,v2 2,v3 2) Within k times of/3), the symbol is decided as a transition symbol, thereby causing no error code. k is a real number not less than 1 and can be determined according to the interference amplitude at the carrier frequency of the channel, 4FSK is generally set to 6, 2FSK is set to 2, namely, the interference within 2 times of the signal amplitude in the channel is resisted. The decision process is as follows:
v0 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is1 2＞B1 u、v2 2＞B2 u、v3 2＞B3 uSatisfy more than one and v0 2＞k(v1 2+v2 2+v3 2) And/3, the judgment result J is a symbol '0';
v1 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2＞B0 u、v2 2＞B2 u、v3 2＞B3 uSatisfy more than one and v1 2＞k(v0 2+v2 2+v3 2) And/3, the judgment result J is a symbol '1';
v2 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2＞B0 u、v1 2＞B1 u、v3 2＞B3 uSatisfy more than one and v2 2＞k(v0 2+v1 2+v3 2) And/3, the judgment result J is a symbol of '2';
v3 2＝max(v0 2,v1 2,v2 2,v3 2) Under the condition of v is0 2＞B0 u、v1 2＞B1 u、v2 2＞B2 uSatisfy more than one and v3 2＞k(v0 2+v1 2+v2 2) And/3, the judgment result J is a symbol '3';
other than the above condition, i.e. max (v)0 2,v1 2,v2 2,v3 2)≤k(v0 2+v1 2+v2 2-max(v0 2,v1 2,v2 2,v3 2) 3), and any one of the demodulation results except the maximum value exceeds a set threshold, wherein the decision result J is a transition symbol 'z';
the decision formula for the current symbol J is as follows:
the device judges that strong interference occurs at the carrier frequency of a channel by the condition that the incoherent demodulation result of an incoherent demodulation frequency point exceeds a decision threshold value, the traditional incoherent demodulation mode cannot be used for correct processing, and the result is wrongly judged as a symbol corresponding to the interference frequency.
A pre-synchronization signal generation step S104, calculating the sum of soft information S corresponding to M symbols, and generating a pre-synchronization signal when the sum is not less than a set threshold value T, the M judgment results are compared with known heartbeat control packet code words without error codes, and the transition symbol 'z' does not count the error codes, or else, the pre-synchronization signal is not generated;
specifically, the sum of the soft information corresponding to the M symbols obtained by calculation is not less than a threshold T, the threshold T is set to be related to the number of symbols M and the modulation mode, and T can be 250 under the 2FSK incoherent demodulation condition when M is 15; under the condition of 4FSK noncoherent demodulation, when M is 15, T can be taken as 750, and when the sum of soft information meets a threshold value and M symbol judgment results are error-free, the device generates a presynchronization signal. The soft information S and the calculation of the soft information S sum further reduce the false alarm probability of the incoherent demodulation and detection of the heartbeat control packet modulated by the FSK, and due to the existence of the soft information sum threshold T, the incoherent demodulation value of a certain communication frequency point meets the judgment threshold B even under the interference of Gaussian white noise0 u、B1 u、B2 u、B3 uThe average soft information of each symbol must be high enough to ensure that the sum of the soft information reaches the requirement of the threshold value T, and the soft information value at the position of the transition symbol is judged to be less than k, even if the receiving end judges too many transition symbols without a heartbeat control packet due to noise interference, the communication has no error code, but the soft information and the threshold value T are not met, and the pre-synchronization signal cannot be generated.
The soft information S calculation expression of the corresponding symbol is as follows:
a demodulation and detection step S105, which performs signal demodulation and detection once every effective sampling length L, and determines that a heartbeat control packet is detected when p or more presynchronization signals are continuously generated.
Specifically, due to the limitation of hardware conditions, incoherent demodulation and detection of a heartbeat control packet of FSK modulation cannot be completed once at each sampling time, in order to reserve sufficient time for a system and enable detection to have high resolution, signal demodulation and detection are performed once every effective sampling length L, and if p or more presynchronization signals are continuously generated, the heartbeat control packet is judged to be detected, so that the signal false alarm phenomenon caused by accidental factors is avoided.
The effective sampling length L is a fixed value and is larger than the time length for detecting the heartbeat control packet once, and the system does incoherent demodulation and detection of the heartbeat control packet once at intervals.
In order to ensure that the decision threshold value changes along with the channel self-adaption, the method further comprises the following steps:
and an iteration step S106, after determining that the heartbeat control packet is detected, continuously performing M-symbol incoherent demodulation, learning and iteratively updating a decision threshold value in an idle time slot of the heartbeat control packet to obtain an adjusted decision threshold value, and repeating the decision step, the presynchronization signal generation step and the demodulation and detection step to obtain a final heartbeat control packet.
Specifically, iteration is carried out on the decision threshold value in the idle time slot of the heartbeat control packet to obtain B0 u+1、B1 u+1、B2 u+1、B3 u+1The value can be obtained from the following equation:
and learning the decision threshold in the idle time slot of the heartbeat control packet and updating the decision threshold in an iterative manner to obtain an adjusted decision threshold, wherein the iterative decision threshold is mainly calculated by the current decision threshold and an incoherent demodulation result in the idle time slot.
In summary, a schematic structural diagram of the demodulation and detection method of the present invention is obtained, as shown in fig. 5.
The simulation results of the present invention are shown in fig. 6 and 7, the heartbeat control packet adopts FSK mode, and it is assumed that the system receives 1 time signal amplitude frequency f while receiving the heartbeat control packet0The interference influence of the FSK heartbeat control packet is that the traditional technology is adopted to carry out incoherent demodulation and detection on the heartbeat control packet, and a correct code word cannot be demodulated due to the existence of strong interference at a communication frequency point, as shown in figure 6, a presynchronization signal cannot be generated, but the incoherent demodulation and detection method of the FSK heartbeat control packet under the strong interference effectively overcomes the influence caused by the strong interference of the signal frequency point, and as a result, as shown in figure 7, a plurality of presynchronization signals can be correctly generated, and when the number of the presynchronization signals reaches p or more, the heartbeat control packet is detected.
The technical scheme provided by the embodiment of the invention designs a method for noncoherent demodulation and detection of the heartbeat control packet, and realizes the function that the noncoherent demodulation and detection system of the heartbeat control packet can still continue to work stably when large-amplitude interference occurs at a communication carrier frequency.
Example 2:
fig. 8 is a block diagram of an apparatus for noncoherently demodulating and detecting a heartbeat control packet according to an embodiment of the present invention, where the apparatus can execute any method for noncoherently demodulating and detecting a heartbeat control packet according to any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method. The device includes:
an obtaining module 901, configured to obtain a heartbeat control packet;
an incoherent demodulation module 902, configured to perform incoherent demodulation on the obtained heartbeat control packet to obtain M FSK incoherent demodulation results;
a decision module 903, configured to perform decision according to a size relationship between the incoherent demodulation result and a decision threshold to obtain a decision symbol result or a transition symbol "z", and calculate soft information S of a corresponding symbol;
a pre-synchronization signal generation module 904, configured to calculate a sum of soft information S corresponding to the M symbols, and generate a pre-synchronization signal when the sum is not less than a set threshold T, and the M decision results are compared with known heartbeat control packet codewords without error codes, and a transition symbol "z" does not count in an error code, otherwise, the pre-synchronization signal is not generated;
the demodulation and detection module 905 is configured to demodulate and detect a signal every effective sampling length L, and determine that a heartbeat control packet is detected when p or more presynchronization signals are continuously generated.
Further comprising: an iteration module 906, configured to determine that M symbol incoherent demodulation is performed after the heartbeat control packet is detected, learn and iteratively update the decision threshold in an idle time slot of the heartbeat control packet to obtain an adjusted decision threshold, and repeat the decision step, the pre-synchronization signal generation step, and the demodulation and detection step to obtain a final heartbeat control packet.
Example 3:
an embodiment of the present invention further provides an electronic device, including:
one or more processors;
a memory for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the method of embodiment 1.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described device embodiments are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit 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 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 Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A method for noncoherent demodulation and detection of heartbeat control packets, comprising:
an acquisition step, which is used for acquiring a data packet to be detected;
an incoherent demodulation step, which is used for carrying out incoherent demodulation on the acquired data packet to be detected to obtain M FSK incoherent demodulation results;
a decision step for making a decision according to the magnitude relation between the non-coherent demodulation result and the decision threshold value to obtain a decision symbol result or a transition symbol "z", and calculating the soft information of the corresponding symbolS；
A pre-synchronization signal generation step for calculating soft information corresponding to the M symbolsSWhen the sum is not less than a set threshold valueTComparing the M judgment results with the known heartbeat control packet code word without error codes, generating a pre-synchronization signal when a transition symbol 'z' does not enter the error codes, or not generating the pre-synchronization signal;
a demodulation and detection step for every effective sampling lengthLPerforming signal demodulation and detection once, and continuously generatingpJudging that the heartbeat control packet is detected when the number of the pre-synchronization signals is more than or equal to the preset number;
wherein, the determining according to the magnitude relation between the non-coherent demodulation result and the determination threshold value to obtain the determination symbol result or the transition symbol "z" includes:
except the maximum incoherent demodulation result, under the condition that other demodulation results are smaller than a decision threshold value, the decision result is a symbol corresponding to the maximum incoherent demodulation result;
except for the maximum incoherent demodulation result, under the condition that other demodulation results are not less than the decision threshold, the two cases are divided at this time: with maximum value greater than the mean of the other demodulation resultskWhen the time is doubled, the judgment result is the symbol corresponding to the maximum incoherent demodulation result; with maximum value less than or equal to the mean of the other demodulation resultskWhen the time is doubled, the judgment result is a transition symbol 'z';
wherein the soft information of the corresponding symbolSThe calculation expression is as follows:
2. the method of claim 1, further comprising:
an iteration step for determining whether the heartbeat control packet is detected and then continuing to performMAnd (3) carrying out incoherent demodulation on each symbol, learning and iteratively updating a decision threshold value in an idle time slot of the heartbeat control packet to obtain an adjusted decision threshold value, and repeating the decision step, the presynchronization signal generation step and the demodulation and detection step to obtain a final heartbeat control packet.
3. The method of claim 1, wherein obtaining the data packet to be detected and then performing incoherent demodulation to obtain M FSK incoherent demodulation results comprises:
for the obtained data packets to be detected, M data packets are usedFSKIntercepting the signal waveform window function of the signal length to obtain the receiving data corresponding to M symbols;
setting a non-coherent demodulation frequency;
dividing the received data corresponding to each symbol into multiple paths, and multiplying the multiple paths by a sine signal and a cosine signal corresponding to demodulation frequency respectively;
and summing the signals of each path, and calculating the square sum of the summation results of the same demodulation frequency to obtain the incoherent demodulation results of the frequency points corresponding to the M symbols.
4. The method of claim 3, wherein: the demodulation frequency is the frequency used by the heartbeat control packet FSK modulation.
5. The method of claim 1, wherein the effective sample lengthLThe length of the time interval is larger than the time length for detecting the heartbeat control packet, and the system performs incoherent demodulation and detection on the heartbeat control packet at every interval.
6. An apparatus for noncoherent demodulation and detection of heartbeat control packets, comprising:
the acquisition module is used for acquiring a data packet to be detected;
the noncoherent demodulation module is used for performing noncoherent demodulation on the acquired data packet to be detected to obtain M FSK noncoherent demodulation results;
a decision module for making a decision according to the magnitude relation between the non-coherent demodulation result and the decision threshold value to obtain a decision symbol result or a transition symbol "z", and calculating the soft information of the corresponding symbolS；
A pre-synchronization signal generation module for calculating soft information corresponding to M symbolsSWhen the sum is not less than a set threshold valueTComparing the M judgment results with the known heartbeat control packet code word without error codes, generating a pre-synchronization signal when a transition symbol 'z' does not enter the error codes, or not generating the pre-synchronization signal;
a demodulation and detection module for every effective sampling lengthLPerforming signal demodulation and detection once, and continuously generatingpJudging that the heartbeat control packet is detected when the number of the pre-synchronization signals is more than or equal to the preset number;
wherein, the determining according to the magnitude relation between the non-coherent demodulation result and the determination threshold value to obtain the determination symbol result or the transition symbol "z" includes:
except the maximum incoherent demodulation result, under the condition that other demodulation results are smaller than a decision threshold value, the decision result is a symbol corresponding to the maximum incoherent demodulation result;
removing maximum incoherenceBesides the demodulation result, under the condition that other demodulation results are not less than the decision threshold, the two cases are divided at this time: with maximum value greater than the mean of the other demodulation resultskWhen the time is doubled, the judgment result is the symbol corresponding to the maximum incoherent demodulation result; with maximum value less than or equal to the mean of the other demodulation resultskWhen the time is doubled, the judgment result is a transition symbol 'z';
wherein the soft information of the corresponding symbolSThe calculation expression is as follows:
7. the apparatus of claim 6, further comprising:
an iteration module for determining whether the heartbeat control packet is detected and then continuing to performMAnd (3) carrying out incoherent demodulation on each symbol, learning and iteratively updating a decision threshold value in an idle time slot of the heartbeat control packet to obtain an adjusted decision threshold value, and repeating the decision step, the presynchronization signal generation step and the demodulation and detection step to obtain a final heartbeat control packet.
8. An electronic device, comprising:
one or more processors;
a memory for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the method of any one of claims 1-5.
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