CN114257357A - Method and device for detecting leader sequence signal - Google Patents
Method and device for detecting leader sequence signal Download PDFInfo
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Abstract
The invention discloses a method for detecting a leader sequence signal, which comprises the following steps: acquiring a channel impulse response signal output by a matched filter and a delayed communication signal output by a delayer, wherein the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal; inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal; and determining a detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold, wherein the detection result is used for indicating the existence or nonexistence of the wireless communication signal by a preamble sequence signal. Therefore, the detection accuracy of the leader sequence signal in the wireless communication signal can be improved by implementing the method, and the performance of the wireless communication technology can be improved.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for detecting a preamble sequence signal.
Background
In the wireless communication technology, since the transmission environment of electromagnetic waves is complex and variable, a preamble sequence signal is usually set in a wireless communication signal, a receiving device of the wireless communication signal determines whether there is a valid wireless communication signal in the surrounding environment by detecting the preamble sequence signal in the surrounding environment, and when it is determined that there is a valid wireless communication signal, the receiving device performs a related preparation operation to prepare for receiving the valid wireless communication signal.
In practical application, the receiving device detects the preamble sequence signal in the surrounding environment through the matched filter, when the preamble sequence signal appears in the surrounding environment, the matched filter in the receiving device outputs a peak with a theoretically optimal signal-to-noise ratio, and whether the preamble sequence signal exists in the surrounding environment can be accurately judged by detecting whether the peak appears in the output of the matched filter. However, the wireless communication signal has abundant phenomena of reflection, refraction, diffraction, etc. during the propagation process of the actual channel, which causes the generation of multiple physical propagation paths, each propagation path will apply delay and attenuation to the wireless communication signal, thereby causing a multipath phenomenon, which results in that after the matched filter in the receiving device detects the preamble sequence signal, the output ideal strong peak is hashed into multiple weak peaks in time, and the signal-to-noise ratio of each weak peak is lower than that of the ideal strong peak, which is not favorable for the receiving device to accurately detect the preamble sequence signal. In addition, noise (e.g., thermal noise, flicker noise, etc.) exists at all times in the actual transmission environment of the wireless communication signal, and the noise is collected at the output port of the matched filter, which also affects the detection accuracy of the preamble sequence signal by the receiving device. Therefore, how to improve the detection accuracy of the preamble sequence signal is a difficult problem still to be solved in the prior art.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a method and an apparatus for detecting a preamble sequence signal, where a channel impulse response signal is input to a norm calculation module to obtain a first norm signal, so as to achieve weighting of the channel impulse response signal, thereby improving detection gain, a delay communication signal is input to a norm calculation module to obtain a second norm signal, so as to achieve weight reduction of the delay communication signal, thereby suppressing noise jitter, and finally a detection result of a wireless communication signal is determined according to the first norm signal and the second norm signal, thereby improving detection accuracy of the preamble sequence signal in the wireless communication signal, and facilitating improvement of performance of a wireless communication technology.
In order to solve the above technical problem, a first aspect of the present invention discloses a method for detecting a preamble sequence signal, where the method includes:
acquiring a channel impulse response signal output by a matched filter and a delayed communication signal output by a delayer, wherein the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal;
inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal;
and determining a detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold, wherein the detection result is used for indicating the existence or nonexistence of the wireless communication signal by a preamble sequence signal.
As an optional implementation manner, in the first aspect of the present invention, the respectively inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal includes:
determining a first parameter and a second parameter of a norm calculation module;
inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal;
and inputting the delayed communication signal and the second parameter into the norm calculation module for analysis to obtain a second norm signal.
As an optional implementation manner, in the first aspect of the present invention, the first parameter includes a first sub-parameter and a second sub-parameter, the second parameter includes a third sub-parameter and a fourth sub-parameter, and the fourth sub-parameter is equal to the second sub-parameter;
and inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal, including:
inputting the first sub-parameter, the second sub-parameter and the channel impulse response signal into the norm calculation module for analysis to obtain a first norm signal;
wherein, after receiving the first sub-parameter, the second sub-parameter and the channel impulse response signal, the norm calculation module is configured to, based on the first sub-parameter and the second sub-parameter, perform the following processing on the channel impulse response signal:
in the formula, La(n) is the first norm signal, h (i) is the channel impulse response signal, a is the first subparameter, and m is the second subparameter;
and inputting the delayed communication signal and the second parameter into the norm calculation module for analysis to obtain a second norm signal, including:
inputting the third sub-parameter, the fourth sub-parameter and the delayed communication signal into the norm calculation module for analysis to obtain a second norm signal;
wherein the norm calculation module is configured to, after receiving the third subparameter, the fourth subparameter and the delayed communication signal, based on the third subparameter and the fourth subparameter, perform the following processing on the delayed communication signal:
in the formula, Lb(n) is the second norm signal, r (i- τ) is the delayed communication signal, b is the third norm signalSubparameter, x is the fourth subparameter.
As an optional implementation manner, in the first aspect of the present invention, the first sub-parameter is greater than 1, and the third sub-parameter is greater than 0 and less than 1.
As an optional implementation manner, in the first aspect of the present invention, the second sub-parameter or the fourth sub-parameter includes a coefficient of a low-pass filter.
As an optional implementation manner, in the first aspect of the present invention, the determining a detection result of the wireless communication signal according to the first norm signal, the second norm signal, and the determined norm signal threshold includes:
calculating a norm signal ratio of the first norm signal and the second norm signal;
judging whether the norm signal ratio is greater than or equal to the determined norm signal threshold;
when the norm signal ratio is judged to be greater than or equal to the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal has a leader sequence signal;
and when the norm signal ratio is judged to be not more than the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal does not have the leader sequence signal.
As an optional implementation manner, in the first aspect of the present invention, the matched filter is configured to convolve the received wireless communication signal and a local communication signal to obtain the channel impulse response signal.
The second aspect of the present invention discloses a preamble sequence signal detection apparatus, which includes:
an obtaining module, configured to obtain a channel impulse response signal output by a matched filter and a delayed communication signal output by a delay, where the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal;
the analysis module is used for inputting the channel impulse response signal and the delayed communication signal into the norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal;
a determining module, configured to determine a detection result of the wireless communication signal according to the first norm signal, the second norm signal, and the determined norm signal threshold, where the detection result is used to indicate that a preamble sequence signal exists or does not exist in the wireless communication signal.
As an alternative embodiment, in the second aspect of the present invention, the analysis module includes:
the determining submodule is used for determining a first parameter and a second parameter of the norm calculating module;
the analysis submodule is used for inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal;
the analysis submodule is further configured to input the delayed communication signal and the second parameter to the norm calculation module for analysis, so as to obtain a second norm signal.
As an optional implementation manner, in the second aspect of the present invention, the first parameter includes a first sub-parameter and a second sub-parameter, the second parameter includes a third sub-parameter and a fourth sub-parameter, and the fourth sub-parameter is equal to the second sub-parameter;
and the analysis submodule inputs the channel impulse response signal and the first parameter into the norm calculation module for analysis, and the specific way of obtaining a first norm signal is as follows:
inputting the first sub-parameter, the second sub-parameter and the channel impulse response signal into the norm calculation module for analysis to obtain a first norm signal;
wherein, after receiving the first sub-parameter, the second sub-parameter and the channel impulse response signal, the norm calculation module is configured to, based on the first sub-parameter and the second sub-parameter, perform the following processing on the channel impulse response signal:
in the formula, La(n) is the first norm signal, h (i) is the channel impulse response signal, a is the first subparameter, and m is the second subparameter;
and the analysis submodule inputs the delayed communication signal and the second parameter into the norm calculation module for analysis, and the specific way of obtaining a second norm signal is as follows:
inputting the third sub-parameter, the fourth sub-parameter and the delayed communication signal into the norm calculation module for analysis to obtain a second norm signal;
wherein the norm calculation module is configured to, after receiving the third subparameter, the fourth subparameter and the delayed communication signal, based on the third subparameter and the fourth subparameter, perform the following processing on the delayed communication signal:
in the formula, Lb(n) is the second norm signal, r (i- τ) is the delayed communication signal, b is the third sub-parameter, and x is the fourth sub-parameter.
As an optional implementation manner, in the second aspect of the present invention, the first sub-parameter is greater than 1, and the third sub-parameter is greater than 0 and less than 1.
As an alternative implementation, in the second aspect of the present invention, the second sub-parameter or the fourth sub-parameter includes a coefficient of a low-pass filter.
As an optional implementation manner, in the second aspect of the present invention, a specific manner of determining, by the determining module, the detection result of the wireless communication signal according to the first norm signal, the second norm signal, and the determined norm signal threshold is as follows:
calculating a norm signal ratio of the first norm signal and the second norm signal;
judging whether the norm signal ratio is greater than or equal to the determined norm signal threshold;
when the norm signal ratio is judged to be greater than or equal to the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal has a leader sequence signal;
and when the norm signal ratio is judged to be not more than the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal does not have the leader sequence signal.
As an optional implementation manner, in the second aspect of the present invention, the matched filter is configured to convolve the received wireless communication signal and a local communication signal to obtain the channel impulse response signal.
The third aspect of the present invention discloses another preamble sequence signal detection apparatus, including:
a memory storing executable program code;
a processor coupled with the memory;
the processor calls the executable program code stored in the memory to execute the preamble sequence signal detection method disclosed by the first aspect of the invention.
In a fourth aspect, the present invention discloses a computer-readable storage medium, which stores computer instructions for executing the method for detecting a preamble sequence signal disclosed in the first aspect of the present invention when the computer instructions are called.
Compared with the prior art, the invention has the following beneficial effects:
the embodiment of the invention firstly obtains the channel impulse response signal and the time-delay communication signal, then inputs the channel impulse response signal and the time-delay communication signal into the norm calculation module for analysis respectively to obtain a first norm signal and a second norm signal respectively, and finally determines the detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold. Therefore, the channel impulse response signal is input into the norm calculation module to obtain the first norm signal, weighting of the channel impulse response signal is achieved, detection gain is improved, the delay communication signal is input into the norm calculation module to obtain the second norm signal, weight reduction of the delay communication signal is achieved, noise jitter is restrained, and finally the detection result of the wireless communication signal is determined according to the first norm signal and the second norm signal, so that detection accuracy of a leader sequence signal in the wireless communication signal can be improved, and performance of a wireless communication technology is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced 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 based on these drawings without creative efforts.
FIG. 1 is a schematic block diagram of a preamble signal detection method according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a preamble sequence signal detection method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a channel impulse response according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a channel impulse response signal according to an embodiment of the present invention;
FIG. 5 is a block diagram of an exemplary engineering implementation of a norm calculation module as referenced in an embodiment of the present invention;
FIG. 6 is a flow chart of another preamble sequence signal detection method disclosed in the embodiment of the present invention;
fig. 7 is a schematic structural diagram of a preamble sequence signal detection apparatus according to an embodiment of the present invention;
FIG. 8 is a schematic structural diagram of another preamble sequence signal detection apparatus disclosed in the embodiment of the present invention;
fig. 9 is a schematic structural diagram of another preamble sequence signal detection apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, 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 only a part of the embodiments of the present invention, 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 invention.
The terms "first," "second," and the like in the description and claims of the present invention and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or apparatus that comprises a list of steps or elements is not limited to those listed but may alternatively include other steps or elements not listed or inherent to such process, method, product, or apparatus.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The invention discloses a method and a device for detecting a leader sequence signal, which are characterized in that a channel impulse response signal is input into a norm calculation module to obtain a first norm signal, the channel impulse response signal is weighted, the detection gain is improved, a delay communication signal is input into a norm calculation module to obtain a second norm signal, the delay communication signal is down weighted, the noise jitter is inhibited, and finally the detection result of the wireless communication signal is determined according to the first norm signal and the second norm signal, so that the detection accuracy of the leader sequence signal in the wireless communication signal can be improved, and the performance of the wireless communication technology is improved.
In order to facilitate understanding of the scheme in the embodiment of the present invention, the signal processing flow mentioned in the embodiment of the present invention is described below with reference to fig. 1. First, a wireless communication signal r (n) is received by a wireless communication receiver, and the wireless communication signal r (n) and a local communication signal S are transmittedlocInputting the signal to a matched filter to obtain a channel impulse response signal h (n), and inputting the channel impulse response signal h (n) and a first parameter (a, m) comprising a first sub-parameter a and a second sub-parameter m into a norm calculation module to obtain a first norm signal La(n) of (a). Inputting a wireless communication signal r (n) into a delay matching module to obtain a delay communication signal r (n-tau), and inputting the delay communication signal r (n-tau) and a second parameter (b, x) comprising a third sub-parameter b and a fourth sub-parameter x into a norm calculation module to obtain a second norm signal Lb(n), wherein the delay coefficient τ of the delay matching module is given by the matched filter to represent the processing delay of the matched filter. The first norm signal La(n) and a second norm signal Lb(n) inputting the division module to obtain the quotient L of the twoab(n), finally, dividing the quotient LabAnd (n) and the norm signal threshold y are input into the comparator module to output a detection result.
Example one
Referring to fig. 2, fig. 2 is a flowchart illustrating a method for detecting a preamble sequence signal according to an embodiment of the present invention. As shown in fig. 2, the preamble sequence signal detection method may include the following operations:
101. and acquiring a channel impulse response signal output by the matched filter and a delay communication signal output by the delay device.
In the above step 101, the channel impulse response signal and the delayed communication signal are generated based on the received wireless communication signal.
Wireless communication waveforms typically carry preamble field waveforms with good autocorrelation characteristics for receiver detection and synchronization. Meanwhile, in order to prevent the distortion caused by peak clipping or compression by the rf front end of the transmitter, the preamble field waveform generally has a low peak-to-average power ratio. The signals in the air are detected by placing a matched filter in the receiver. When the waveform of the preamble field appears in the air, the output port of the matched filter appears a peak, and the peak has a theoretically optimal signal-to-noise ratio, so that whether the effective communication signal exists in the air currently can be accurately judged by detecting whether the peak appears.
In addition, the wireless communication signal has abundant phenomena of reflection, refraction, diffraction and the like in the propagation process of an actual channel, which causes the generation of a plurality of physical propagation paths, each propagation path applies delay and attenuation to the wireless communication signal, thereby causing a multipath phenomenon, which causes an ideal strong peak output by a matched filter in receiving equipment to be hashed into a plurality of weak peaks in time after detecting a preamble sequence signal, the signal-to-noise ratio of each weak peak is lower than that of the ideal strong peak, and a signal formed by the weak peaks is called as a channel impulse response, as shown in fig. 3. In addition, noise (for example, thermal noise, flicker noise, etc.) exists at all times in the actual transmission environment of the wireless communication signal, the noise is collected at the output port of the matched filter, when the preamble sequence signal arrives, the superposition of the channel impulse response and the noise appears at the output port of the matched filter, and the superposed signal is the channel impulse response signal, as shown in fig. 4.
Further, the matched filter may be used to convolve the received wireless communication signal with the local communication signal to obtain a channel impulse response signal. The local communication signal refers to a communication signal that is predetermined by the wireless communication receiver when receiving the wireless communication signal.
102. And respectively inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal.
In an optional embodiment, the respectively inputting the channel impulse response signal and the delayed communication signal into the norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal, which includes:
determining a first parameter and a second parameter of a norm calculation module;
inputting the channel impulse response signal and the first parameter into a norm calculation module for analysis to obtain a first norm signal;
and inputting the delay communication signal and the second parameter into a norm calculation module for analysis to obtain a second norm signal.
It can be seen that, by implementing the optional embodiment, the channel impulse response signal is analyzed based on the first parameter, and the delayed communication signal is analyzed based on the second parameter, so that the first norm signal and the second norm signal can be obtained.
In this optional embodiment, it is further optional that the first parameter includes a first sub-parameter and a second sub-parameter, the second parameter includes a third sub-parameter and a fourth sub-parameter, and the fourth sub-parameter is equal to the second sub-parameter;
and inputting the channel impulse response signal and the first parameter into a norm calculation module for analysis to obtain a first norm signal, wherein the method comprises the following steps:
inputting the first sub-parameter, the second sub-parameter and the channel impulse response signal into a norm calculation module for analysis to obtain a first norm signal;
after receiving the first sub-parameter, the second sub-parameter and the channel impulse response signal, the norm calculation module is configured to perform the following processing on the channel impulse response signal based on the first sub-parameter and the second sub-parameter:
in the formula, La(n) is the first norm signal, h (i) is the channel impulse response signal, a is the first subparameter, m is the second subparameter;
and inputting the delay communication signal and the second parameter into a norm calculation module for analysis to obtain a second norm signal, wherein the method comprises the following steps:
inputting the third sub-parameter, the fourth sub-parameter and the delayed communication signal into a norm calculation module for analysis to obtain a second norm signal;
after receiving the third subparameter, the fourth subparameter and the delayed communication signal, the norm calculation module is configured to perform the following processing on the delayed communication signal based on the third subparameter and the fourth subparameter:
in the formula, Lb(n) is the second norm signal, r (i- τ) is the delayed communication signal, b is the third sub-parameter, and x is the fourth sub-parameter.
In this further alternative embodiment, La(n) and LbA typical engineering implementation of the calculation formula of (n) is shown in fig. 5, where | x | represents a modulo operation, conv (,) represents a convolution operation, and ones (m) represents a full 1 sequence of length m. When calculating the first norm signal La(n), when p is a, the second norm signal L is calculatedbWhen (n) is used, p is b.
La(n) and LbThe nature of the calculation formula of (n) shows that the calculation result of the formula depends more on the peak value of the input signal when p is larger, and depends more on the average value of the input signal when p is smaller, so that L can be adjusted by selecting proper a and ba(n) and Lb(n) dependence on the peak in h (n) and r (n- τ). Specifically, since the channel impulse response in h (n) exists in the form of discrete peaks, a is selected>1 may be such that La(n) contain more channel impulse response information. In addition, because the preamble waveform typically has a low peak-to-average power ratio, the peak in r (n- τ) is contributed by noise, when 0 is chosen<b<1 may be such that Lb(n) contains less noise information. L can be improved under the condition of the same signal-to-noise ratio by reasonably selecting the values of m, a and ba(n) and Lb(n) to improve the accuracy of the detection.
Preferably, the first sub-parameter is greater than 1 and the third sub-parameter is greater than 0 and less than 1.
Preferably, the second or fourth sub-parameter comprises a coefficient of a low-pass filter. The low-pass filter may be an FIR filter or an IIR filter.
It can be seen that, in this further alternative embodiment, the channel impulse response signal is analyzed based on the first sub-parameter and the second sub-parameter, and the delayed communication signal is analyzed based on the third sub-parameter and the fourth sub-parameter, so that the first norm signal and the second norm signal can be obtained. In addition, by setting the first sub-parameter and the third sub-parameter to appropriate values, the ratio of the first norm signal to the second norm signal under the same signal-to-noise ratio can be improved, thereby improving the accuracy of detection.
103. And determining the detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold.
In the above step 103, the detection result is used to indicate the presence or absence of the preamble signal in the wireless communication signal.
In another alternative embodiment, determining a detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold includes:
calculating a norm signal ratio of the first norm signal and the second norm signal;
judging whether the norm signal ratio is greater than or equal to the determined norm signal threshold;
when the norm signal ratio is judged to be greater than or equal to the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal has a leader sequence signal;
and when the norm signal ratio is judged to be not more than the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal does not have the leader sequence signal.
In this alternative embodiment, when the norm signal ratio is greater than or equal to the norm signal threshold, it indicates that there is a spike in the wireless communication signal, i.e., there is a preamble signal in the wireless communication signal.
Alternatively, whether the preamble sequence signal exists in the wireless communication signal may also be determined by determining whether the first norm signal is greater than or equal to a second norm signal of a preset multiple.
It can be seen that, in implementing this alternative embodiment, by determining whether the ratio of the norm signals of the first norm signal and the second norm signal is greater than or equal to the determined norm signal threshold, it can be determined whether the preamble sequence signal exists in the wireless communication signal.
It can be seen that, with the method for detecting a preamble sequence signal described in fig. 2, a channel impulse response signal is input to the norm calculation module to obtain a first norm signal, thereby implementing weighting of the channel impulse response signal, and thus improving detection gain, a delay communication signal is input to the norm calculation module to obtain a second norm signal, thereby implementing weighting reduction of the delay communication signal, thereby suppressing noise jitter, and finally, a detection result of a wireless communication signal is determined according to the first norm signal and the second norm signal, thereby improving detection accuracy of the preamble sequence signal in the wireless communication signal, and facilitating improvement of performance of a wireless communication technology. In addition, the channel impulse response signal is analyzed based on the first sub-parameter and the second sub-parameter, the delay communication signal is analyzed based on the third sub-parameter and the fourth sub-parameter, and the ratio of the first norm signal to the second norm signal under the same signal-to-noise ratio condition can be improved by setting the first sub-parameter and the third sub-parameter to appropriate values, so that the detection accuracy is improved.
Example two
Referring to fig. 6, fig. 6 is a flowchart illustrating another preamble sequence signal detection method according to an embodiment of the present invention. As shown in fig. 6, the method for detecting a preamble sequence signal may include the following operations:
201. and acquiring a channel impulse response signal output by the matched filter and a delay communication signal output by the delay device.
202. And respectively inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal.
203. And determining the detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold.
For the detailed description of the steps 201-203, reference may be made to the detailed description of the steps 101-103, which is not described in detail herein.
204. And when the detection result is used for indicating that the wireless communication signal has the preamble sequence signal, judging whether the average power of the wireless communication signal is larger than or equal to a predetermined power threshold value. When the determination result in step 204 is no, step 205 may be triggered to be executed, and when the determination result in step 204 is yes, the process may be ended.
205. And analyzing the wireless communication signals to obtain corresponding wireless communication data.
In step 204 and step 205, the average power of the wireless communication signal may fluctuate greatly, and when the fluctuation of the average power of the wireless communication signal is too large, the signal with too large power may easily cause a peak at the output port of the matched filter, and then the signal with too large power is erroneously determined as the preamble sequence signal, which causes an erroneous determination.
In an optional embodiment, after parsing the wireless communication signal to obtain corresponding wireless communication data, the method further includes:
judging whether the wireless communication data contains a lead code;
and when the wireless communication data is judged not to contain the preamble, modifying the detection result to be used for indicating that the wireless communication signal does not contain the preamble sequence signal.
In this alternative embodiment, the preamble refers to a segment of codes with a predetermined format, which is set in the wireless communication data, and corresponds to the preamble sequence signal in the wireless communication signal, and the preamble sequence signal is analyzed to obtain the preamble. If the wireless communication signal is a valid communication signal, the wireless communication data obtained by analyzing the wireless communication signal includes a preamble.
Therefore, by implementing the optional embodiment, the wireless communication data is obtained by analyzing the wireless communication signal, and then after the wireless communication data is judged not to contain the preamble, the detection result is modified to indicate that the wireless communication signal does not have the preamble sequence signal, so that the accuracy of preamble sequence signal detection can be further improved.
In this optional embodiment, further optionally, the method further includes:
when the wireless communication data is judged to contain the lead code, checking the wireless communication data;
when the verification is failed, triggering to modify the detection result into an operation for indicating that the wireless communication signal has no preamble sequence signal.
In this further alternative embodiment, the manner of checking the wireless communication data is a parity check or a CRC check or an LRC check or a gray code check or an MD5 check. If the wireless communication signal is not a valid communication signal, the analyzed wireless communication data generally cannot pass the verification, so when the wireless communication data fails to pass the verification, the detection result is modified to indicate that the wireless communication signal does not have a preamble sequence signal.
Therefore, by implementing the further optional embodiment, when the wireless communication data contains the preamble and the wireless communication data check fails, the detection result is modified to indicate that no preamble sequence signal exists in the wireless communication signal, so that the accuracy of preamble sequence signal detection can be further improved.
It can be seen that, with the method for detecting a preamble sequence signal described in fig. 6, after the detection result is used to indicate that a preamble sequence signal exists in a wireless communication signal, and after the average power of the wireless communication signal is not greater than or equal to the preset power threshold, the wireless communication signal is analyzed to obtain corresponding wireless communication data, so that the accuracy of the wireless communication data obtained by analysis can be improved, and the performance of the wireless communication technology can be improved. After the wireless communication data is judged not to contain the lead code or after the wireless communication data is judged to contain the lead code and the wireless communication data is not verified, the detection result is modified to indicate that the wireless communication signal does not have the lead sequence signal, and the accuracy of the detection of the lead sequence signal can be further improved.
EXAMPLE III
Referring to fig. 7, fig. 7 is a schematic structural diagram of a preamble sequence signal detection apparatus according to an embodiment of the present invention. As shown in fig. 7, the preamble sequence signal detection apparatus may include:
an obtaining module 701, configured to obtain a channel impulse response signal output by the matched filter and a delayed communication signal output by the delay, where the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal;
an analysis module 702, configured to input the channel impulse response signal and the delayed communication signal to the norm calculation module for analysis, so as to obtain a first norm signal and a second norm signal, respectively;
a determining module 703 is configured to determine a detection result of the wireless communication signal according to the first norm signal, the second norm signal, and the determined norm signal threshold, where the detection result is used to indicate that the wireless communication signal has or does not have a preamble sequence signal.
It can be seen that, with the detection apparatus for preamble sequence signals described in fig. 7, the channel impulse response signal is input to the norm calculation module to obtain the first norm signal, thereby implementing weighting on the channel impulse response signal, and thus improving the detection gain, the delay communication signal is input to the norm calculation module to obtain the second norm signal, thereby implementing weighting reduction on the delay communication signal, thereby suppressing noise jitter, and finally, the detection result of the wireless communication signal is determined according to the first norm signal and the second norm signal, thereby improving the detection accuracy on the preamble sequence signal in the wireless communication signal, and being beneficial to improving the performance of the wireless communication technology.
In an alternative embodiment, the analysis module 702 includes:
a determining submodule 7021 configured to determine a first parameter and a second parameter of the norm calculating module;
the analysis submodule 7022 is configured to input the channel impulse response signal and the first parameter to the norm calculation module for analysis, so as to obtain a first norm signal;
the analysis sub-module 7022 is further configured to input the delayed communication signal and the second parameter to the norm calculation module for analysis, so as to obtain a second norm signal.
It can be seen that, when the preamble sequence signal detection apparatus described in fig. 8 is implemented, the channel impulse response signal is analyzed based on the first parameter and the delayed communication signal is analyzed based on the second parameter, so that the first norm signal and the second norm signal can be obtained.
In this optional embodiment, it is further optional that the first parameter includes a first sub-parameter and a second sub-parameter, the second parameter includes a third sub-parameter and a fourth sub-parameter, and the fourth sub-parameter is equal to the second sub-parameter;
and the analysis submodule 7022 inputs the channel impulse response signal and the first parameter to the norm calculation module for analysis, and the specific way of obtaining the first norm signal is as follows:
inputting the first sub-parameter, the second sub-parameter and the channel impulse response signal into a norm calculation module for analysis to obtain a first norm signal;
after receiving the first sub-parameter, the second sub-parameter and the channel impulse response signal, the norm calculation module is configured to perform the following processing on the channel impulse response signal based on the first sub-parameter and the second sub-parameter:
in the formula, La(n) is the first norm signal, h (i) is the channel impulse response signal, a is the first subparameter, m is the second subparameter;
and the analysis submodule 7022 inputs the delayed communication signal and the second parameter to the norm calculation module for analysis, and the specific way of obtaining the second norm signal is as follows:
inputting the third sub-parameter, the fourth sub-parameter and the delayed communication signal into a norm calculation module for analysis to obtain a second norm signal;
after receiving the third subparameter, the fourth subparameter and the delayed communication signal, the norm calculation module is configured to perform the following processing on the delayed communication signal based on the third subparameter and the fourth subparameter:
in the formula, Lb(n) is the second norm signal, r (i- τ) is the delayed communication signal, b is the third sub-parameter, and x is the fourth sub-parameter.
Preferably, the first sub-parameter is greater than 1 and the third sub-parameter is greater than 0 and less than 1.
Preferably, the second or fourth sub-parameter comprises a coefficient of a low-pass filter.
It can be seen that, when the preamble sequence signal detection apparatus described in fig. 8 is implemented, the channel impulse response signal is analyzed based on the first sub-parameter and the second sub-parameter, and the delayed communication signal is analyzed based on the third sub-parameter and the fourth sub-parameter, so that the first norm signal and the second norm signal can be obtained. In addition, by setting the first sub-parameter and the third sub-parameter to appropriate values, the ratio of the first norm signal to the second norm signal under the same signal-to-noise ratio can be improved, thereby improving the accuracy of detection.
In another optional embodiment, the determining module 703 determines the detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold in a specific manner as follows:
calculating a norm signal ratio of the first norm signal and the second norm signal;
judging whether the norm signal ratio is greater than or equal to the determined norm signal threshold;
when the norm signal ratio is judged to be greater than or equal to the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal has a leader sequence signal;
and when the norm signal ratio is judged to be not more than the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal does not have the leader sequence signal.
It can be seen that, implementing the preamble sequence signal detection apparatus described in fig. 8, by determining whether the ratio of the norm signals of the first norm signal and the second norm signal is greater than or equal to the determined norm signal threshold, it can be determined whether the preamble sequence signal exists in the wireless communication signal.
For a specific description of the preamble sequence signal detection apparatus, reference may be made to the specific description of the preamble sequence signal detection method, which is not described in detail herein.
Example four
Referring to fig. 9, fig. 9 is a schematic structural diagram of another preamble sequence signal detection apparatus according to an embodiment of the present invention. As shown in fig. 9, the apparatus may include:
a memory 901 in which executable program code is stored;
a processor 902 coupled to a memory 901;
the processor 902 calls the executable program code stored in the memory 901 for executing the preamble sequence signal detection method described in the first embodiment or the second embodiment.
EXAMPLE five
The embodiment of the invention discloses a computer-readable storage medium which stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute the preamble sequence signal detection method described in the first embodiment or the second embodiment.
EXAMPLE six
An embodiment of the present invention discloses a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute the preamble sequence signal detection method described in the first embodiment or the second embodiment.
The above-described embodiments of the apparatus are merely illustrative, and the modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above detailed description of the embodiments, those skilled in the art will clearly understand that the embodiments may be implemented by software plus a necessary general hardware platform, and may also be implemented by hardware. Based on such understanding, the above technical solutions may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, where the storage medium includes a Read-Only Memory (ROM), a Random Access Memory (RAM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), a One-time Programmable Read-Only Memory (OTPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Compact Disc-Read-Only Memory (CD-ROM), or other disk memories, CD-ROMs, or other magnetic disks, A tape memory, or any other medium readable by a computer that can be used to carry or store data.
Finally, it should be noted that: the method and apparatus for detecting a preamble sequence signal disclosed in the embodiments of the present invention are only preferred embodiments of the present invention, and are only used for illustrating the technical solutions of the present invention, not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art; the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for detecting a preamble signal, the method comprising:
acquiring a channel impulse response signal output by a matched filter and a delayed communication signal output by a delayer, wherein the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal;
inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal;
and determining a detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold, wherein the detection result is used for indicating the existence or nonexistence of the wireless communication signal by a preamble sequence signal.
2. The method according to claim 1, wherein the step of inputting the channel impulse response signal and the delayed communication signal into a norm calculation module for analysis to obtain a first norm signal and a second norm signal respectively comprises:
determining a first parameter and a second parameter of a norm calculation module;
inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal;
and inputting the delayed communication signal and the second parameter into the norm calculation module for analysis to obtain a second norm signal.
3. The preamble sequence signal detection method according to claim 2, wherein the first parameter comprises a first sub-parameter and a second sub-parameter, the second parameter comprises a third sub-parameter and a fourth sub-parameter, and the fourth sub-parameter is equal to the second sub-parameter;
and inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal, including:
inputting the first sub-parameter, the second sub-parameter and the channel impulse response signal into the norm calculation module for analysis to obtain a first norm signal;
wherein, after receiving the first sub-parameter, the second sub-parameter and the channel impulse response signal, the norm calculation module is configured to, based on the first sub-parameter and the second sub-parameter, perform the following processing on the channel impulse response signal:
in the formula, La(n) is the first norm signal, h (i) is the channel impulse response signal, a is the first subparameter, and m is the second subparameter;
and inputting the delayed communication signal and the second parameter into the norm calculation module for analysis to obtain a second norm signal, including:
inputting the third sub-parameter, the fourth sub-parameter and the delayed communication signal into the norm calculation module for analysis to obtain a second norm signal;
wherein the norm calculation module is configured to, after receiving the third subparameter, the fourth subparameter and the delayed communication signal, based on the third subparameter and the fourth subparameter, perform the following processing on the delayed communication signal:
in the formula, Lb(n) is the second norm signal, r (i- τ) is the delayed communication signal, b is the third sub-parameter, and x is the fourth sub-parameter.
4. The method of claim 3, wherein the first sub-parameter is greater than 1, and the third sub-parameter is greater than 0 and less than 1.
5. The preamble sequence signal detection method according to any one of claims 1 to 4, wherein the second sub-parameter or the fourth sub-parameter comprises a coefficient of a low-pass filter.
6. The method for detecting a preamble sequence signal according to any one of claims 1 to 4, wherein the determining the detection result of the wireless communication signal according to the first norm signal, the second norm signal and the determined norm signal threshold comprises:
calculating a norm signal ratio of the first norm signal and the second norm signal;
judging whether the norm signal ratio is greater than or equal to the determined norm signal threshold;
when the norm signal ratio is judged to be greater than or equal to the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal has a leader sequence signal;
and when the norm signal ratio is judged to be not more than the norm signal threshold, determining that the detection result of the wireless communication signal is used for indicating that the wireless communication signal does not have the leader sequence signal.
7. The preamble sequence signal detection method according to any one of claims 1 to 4, wherein the matched filter is configured to convolve the received wireless communication signal and local communication signal to obtain the channel impulse response signal.
8. An apparatus for detecting a preamble signal, the apparatus comprising:
an obtaining module, configured to obtain a channel impulse response signal output by a matched filter and a delayed communication signal output by a delay, where the channel impulse response signal and the delayed communication signal are generated based on a received wireless communication signal;
the analysis module is used for inputting the channel impulse response signal and the delayed communication signal into the norm calculation module for analysis to respectively obtain a first norm signal and a second norm signal;
a determining module, configured to determine a detection result of the wireless communication signal according to the first norm signal, the second norm signal, and the determined norm signal threshold, where the detection result is used to indicate that a preamble sequence signal exists or does not exist in the wireless communication signal.
9. The apparatus for detecting preamble signal according to claim 8, wherein the analyzing module comprises:
the determining submodule is used for determining a first parameter and a second parameter of the norm calculating module;
the analysis submodule is used for inputting the channel impulse response signal and the first parameter into the norm calculation module for analysis to obtain a first norm signal;
the analysis submodule is further configured to input the delayed communication signal and the second parameter to the norm calculation module for analysis, so as to obtain a second norm signal.
10. An apparatus for detecting a preamble signal, the apparatus comprising:
a memory storing executable program code;
a processor coupled with the memory;
the processor calls the executable program code stored in the memory to execute the preamble sequence signal detection method according to any one of claims 1 to 7.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050047530A1 (en) * | 2003-08-29 | 2005-03-03 | Lee Jung Ah | Method and arrangement for detecting a random access channel preamble using multiple antenna reception in a communication system |
| JP2008085952A (en) * | 2006-09-29 | 2008-04-10 | Fujitsu Ltd | Preamble detection apparatus and radio receiver |
| CN102523185A (en) * | 2011-12-09 | 2012-06-27 | 大唐移动通信设备有限公司 | Preamble sequence detection method and device |
| US20140064203A1 (en) * | 2011-03-18 | 2014-03-06 | Lg Electronics Inc. | Method and device for communicating device-to-device |
| CN103931150A (en) * | 2011-11-15 | 2014-07-16 | 阿科恩科技公司 | OFDM receiver with time domain channel estimation |
| US20170163300A1 (en) * | 2015-12-03 | 2017-06-08 | Mstar Semiconductor, Inc. | Signal detection method and device |
| CN107231225A (en) * | 2017-05-22 | 2017-10-03 | 江苏沁恒股份有限公司 | A kind of leading character sequence detecting method and device |
| CN108736921A (en) * | 2017-04-20 | 2018-11-02 | 中国科学院声学研究所 | A kind of power line carrier communication lead detecting method for resisting random impulsive noise |
-
2020
- 2020-09-24 CN CN202011014350.5A patent/CN114257357A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050047530A1 (en) * | 2003-08-29 | 2005-03-03 | Lee Jung Ah | Method and arrangement for detecting a random access channel preamble using multiple antenna reception in a communication system |
| JP2008085952A (en) * | 2006-09-29 | 2008-04-10 | Fujitsu Ltd | Preamble detection apparatus and radio receiver |
| US20140064203A1 (en) * | 2011-03-18 | 2014-03-06 | Lg Electronics Inc. | Method and device for communicating device-to-device |
| CN103931150A (en) * | 2011-11-15 | 2014-07-16 | 阿科恩科技公司 | OFDM receiver with time domain channel estimation |
| CN102523185A (en) * | 2011-12-09 | 2012-06-27 | 大唐移动通信设备有限公司 | Preamble sequence detection method and device |
| US20170163300A1 (en) * | 2015-12-03 | 2017-06-08 | Mstar Semiconductor, Inc. | Signal detection method and device |
| CN108736921A (en) * | 2017-04-20 | 2018-11-02 | 中国科学院声学研究所 | A kind of power line carrier communication lead detecting method for resisting random impulsive noise |
| CN107231225A (en) * | 2017-05-22 | 2017-10-03 | 江苏沁恒股份有限公司 | A kind of leading character sequence detecting method and device |
Non-Patent Citations (2)
| Title |
|---|
| TAEHOON KIM: "An Enhanced PRACH Preamble Detector for Cellular IoT Communications", IEEE COMMUNICATIONS LETTERS, 31 December 2017 (2017-12-31) * |
| 王丹;张怡凡;杜颜敏;: "基于5G系统的随机接入前导检测算法", 光通信研究, no. 01, 10 February 2020 (2020-02-10) * |
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