WO2022198549A1 - 信道扫描的方法、装置、设备和存储介质 - Google Patents

信道扫描的方法、装置、设备和存储介质 Download PDF

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Publication number
WO2022198549A1
WO2022198549A1 PCT/CN2021/082910 CN2021082910W WO2022198549A1 WO 2022198549 A1 WO2022198549 A1 WO 2022198549A1 CN 2021082910 W CN2021082910 W CN 2021082910W WO 2022198549 A1 WO2022198549 A1 WO 2022198549A1
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signal
frequency offset
current channel
channel
signal sequence
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French (fr)
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黄妮
罗正华
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Hytera Communications Corp Ltd
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Hytera Communications Corp Ltd
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Priority to PCT/CN2021/082910 priority Critical patent/WO2022198549A1/zh
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/08—Testing, supervising or monitoring using real traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information

Definitions

  • the present invention relates to the field of communication technologies, and in particular, to a method, apparatus, device and storage medium for channel scanning.
  • DMR Digital Mobile Radio
  • the existing detection preset time is generally greater than the maximum interval with synchronization.
  • the synchronization interval of the DMR-PDT voice signal is 360ms, and the stay detection preset time must be greater than 360ms. During this period, when there are target calls or data information on other channels in the scan list, it is easy to cause missed calls or call drops.
  • C1-C4 For example, it is assumed that four channels (C1-C4) are configured for scanning, and the configured channels are switched in turn for scanning in each time slot.
  • the channel C2 is scanned, if there is interference on C2, the presence of RSSI and carrier can be detected on this channel, and it will stay on this channel and continue to receive, and judge whether the service is received by whether the synchronization information of DMR-PDT is received. .
  • the synchronization interval of the DMR-PDT standard is voice synchronization
  • a service occurs on the C4 channel, a part of the services in front of the C4 channel will be missed, resulting in the missing of the previous part of the signal. Specifically, if it is a short message service, the signal will not be parsed directly; if it is a voice service, the previously transmitted voice will be lost (that is, the voice is dropped).
  • the present invention provides a method, apparatus, device and storage medium for channel scanning, so as to avoid missing valid signals during channel scanning.
  • a first aspect of the present application provides a method for channel scanning, including:
  • each of the maximum frequency offset envelope mean values calculated within the first period of time are within the required frequency offset range, it is determined that the signal of the current channel is a valid signal; wherein the first period of time is greater than the specified frequency offset.
  • the shard duration is less than the preset synchronization interval;
  • any one of the maximum frequency offset envelope mean values calculated within the first time period is not within the frequency offset requirement range, it is determined that the signal of the current channel is an invalid signal, and the signal in the scan channel list is Designate the next channel as the current channel, and return to performing the scan for the current channel.
  • the power peak value of the signal sequence is located at the symbol rate, and each of the maximum frequency offset envelope mean values calculated within the first time period are within the frequency offset requirement range, determine the current channel The signal is a valid signal.
  • the method before performing fast Fourier transform on the acquired signal sequence composed of each of the frequency offset deviations to obtain the spectrum of the signal sequence, the method further includes:
  • Performing fast Fourier transform on the acquired signal sequence composed of each of the frequency offset deviations to obtain the frequency spectrum of the signal sequence including:
  • Fast Fourier transform is performed on the adjusted signal sequence to obtain the frequency spectrum of the adjusted signal sequence.
  • the signal of the current channel includes synchronization information within the synchronization interval, and each of the maximum frequency offset envelope mean values calculated within the first time period are within the frequency offset requirement range, determine the The signal of the current channel is a valid signal.
  • a second aspect of the present application provides a channel scanning device, including:
  • a scanning unit configured to scan a current channel to obtain a signal of the current channel; wherein, the current channel is any channel in the scan channel list;
  • the calculation unit is configured to calculate the maximum frequency deviation envelope mean value of the signal of the current channel within the fragmentation duration every time a fragmentation duration passes, and determine whether the maximum frequency deviation envelope mean value is within a preset frequency. within the range of partial requirements;
  • a determining unit configured to determine that the signal of the current channel is a valid signal if each of the maximum frequency offset envelope mean values calculated within the first time period are within the frequency offset requirement range; wherein, the The first duration is greater than the segment duration and smaller than the preset synchronization interval;
  • the determining unit is configured to determine that the signal of the current channel is an invalid signal if any one of the maximum frequency offset envelope mean values calculated within the first time period is not within the frequency offset requirement range, and determine the signal of the current channel as an invalid signal.
  • the next channel in the scanning channel list is designated as the current channel, and the scanning of the current channel is returned.
  • the device further includes a judging unit for:
  • the determining unit is configured to, if the power peak value of the signal sequence is located at the symbol rate, and each of the maximum frequency offset envelope mean values calculated within the first time period are within the frequency offset requirement range Inside, it is determined that the signal of the current channel is a valid signal.
  • the judging unit is also used for:
  • the judging unit performs fast Fourier transform on the acquired signal sequence composed of the frequency offset deviation, and when obtaining the frequency spectrum of the signal sequence, the specific execution is as follows:
  • Fast Fourier transform is performed on the adjusted signal sequence to obtain the frequency spectrum of the adjusted signal sequence.
  • the device further includes a detection unit for:
  • the determining unit is configured to, if the signal of the current channel in the synchronization interval includes synchronization information, and each of the maximum frequency offset envelope mean values calculated within the first time period are within the frequency offset value. Within the required range, it is determined that the signal of the current channel is a valid signal.
  • a third aspect of the present application provides an electronic device, including a memory and a processor
  • the memory is used to store computer programs
  • the processor is configured to execute the computer program, and is specifically configured to implement the channel scanning method provided in any one of the first aspect of this application.
  • a fourth aspect of the present application provides a computer storage medium for storing a computer program, and when the computer program is executed, it is specifically used to implement the channel scanning method provided in any one of the first aspect of the present application.
  • a method, device, device and storage medium for channel scanning comprising: scanning a current channel to obtain a signal of the current channel; wherein, the current channel is any channel in the scanning channel list; after each fragmentation time, the calculation is performed in The mean value of the maximum frequency offset envelope of the signal of the current channel within the slice duration, and determine whether the mean value of the maximum frequency offset envelope is within the preset frequency offset requirement range; if each maximum frequency offset envelope calculated within the first duration The average value of the network is within the range of frequency offset requirements, and the signal of the current channel is determined to be a valid signal; wherein, the first duration is greater than the segment duration and smaller than the preset synchronization interval; if any maximum frequency calculated within the first duration The mean value of the partial envelope, which is not within the range of frequency offset requirements, determines that the signal of the current channel is an invalid signal, designates the next channel in the scan channel list as the current channel, and returns to execute the scan of the current channel.
  • FIG. 1 is a flowchart of a method for channel scanning provided by an embodiment of the present application
  • FIG. 2 is a flowchart of a method for channel scanning provided by another embodiment of the present application.
  • FIG. 3 is a schematic spectrum diagram of an adjusted signal sequence provided by an embodiment of the present application.
  • FIG. 4 is a flowchart of a method for channel scanning provided by another embodiment of the present application.
  • FIG. 5 is a flowchart of a method for channel scanning provided by still another embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of an apparatus for channel scanning provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • Digital Mobile Radio (DMR), Digital Mobile Radio and police Digital Trunking (DMR-PDT) are two communication protocols in the field of wireless communication, usually used in the communication of wireless walkie-talkies , a communication system composed of multiple wireless walkie-talkies applying the above-mentioned protocols can be called a DMR system, a DMR-PDT system, etc. accordingly.
  • the modulation of the signal is generally carried out by means of frequency shift keying.
  • the transmitting end generally adopts the 4th generation continuous phase frequency shift keying technology.
  • 4CPFSK continuous phase frequency shift keying
  • the 4CPFSK signal is broadcast through a certain channel, and when any receiving end scans the channel during broadcasting, the above-mentioned carrier signal carrying the information can be obtained from the channel.
  • the sender generally does not directly send the above 4CPFSK signal to the outside, but performs post-processing operations including but not limited to Frequency Modulation (FM) digital-to-analog conversion, frequency conversion, etc. on the 4CPFSK signal, and finally obtains the Air interface signal, and then broadcast the air interface signal through a sending device (such as an antenna).
  • FM Frequency Modulation
  • the receiving end obtains the 4CPFSK signal by scanning the channel, which essentially includes the following process:
  • the digital signal is then subjected to channel filtering, FM demodulation, resampling, and Root Raised Cosine filtering, and finally the 4CPFSK signal transmitted on the channel is obtained.
  • the receiving end needs to scan each channel one by one to determine which channel the transmitting end sends the signal through.
  • the carrier signals may not carry Any information (or the information originally carried is damaged by channel interference), in this application, this type of carrier signal is called an invalid signal (or interference signal), and the carrier signal carrying the information of the sender is called an effective signal. Signal.
  • the receiver During the scanning process, if there is no carrier signal on the currently scanned channel (ie, the current channel), the receiver will immediately switch to the next channel to continue scanning. Stay on for a certain period of time, and continue to scan the current channel, so as to identify whether the carrier signal of the current channel is a valid signal or an invalid signal. If it is an invalid signal, continue to scan the next channel, and if it is a valid signal, start to communicate with the sender.
  • the receiving end may miss the valid signal transmitted on another channel, resulting in the failure to receive the valid signal, or the information interpreted after receiving it is incomplete, that is, the background art
  • the speech is dropped or the valid signal is missed.
  • the purpose of the channel scanning solution provided by the present application is to shorten the time that the receiving end stays on the channel to which the invalid signal belongs during the scanning process as much as possible, so as to avoid the situation that the speech drops or the valid signal is missed.
  • the common invalid signals mainly include analog channel interference signals, blocking interference signals and intermodulation interference signals.
  • the demodulation of the analog channel interference signals is generally white noise or unidentifiable noise. voice.
  • the blocking interference signal specifically includes two situations.
  • the first is the blocking interference signal mixed with the interference signal with higher strength and the effective signal.
  • the interference signal will saturate the nonlinear device at the receiving end, causing nonlinear distortion of the nonlinear device and distorting the effective signal.
  • the second case is an effective signal with an excessively high intensity (referring to a working range higher than the device at the receiving end). If the intensity of the effective signal is too high, the phenomenon of amplitude compression will occur, which will also lead to distortion of the effective signal.
  • Intermodulation interference signals can be specifically divided into analog intermodulation interference signals, digital direct intermodulation interference signals, and digital relay intermodulation interference signals.
  • the signal characteristics after demodulation are consistent with the analog channel interference, which is manifested as white noise and noisy speech.
  • the signal characteristics after demodulation are as follows: the signal with a larger 4CPFSK frequency offset in the overlapping part of the signal, and no carrier in the non-overlapping part, which is a 60ms period signal with an asymmetric duty cycle; there is a certain probability that it can be Detach the sync signal.
  • the characteristics of the signal after digital relay intermodulation modulation are as follows: the overall frequency offset of the signal becomes larger, which is the signal after the amplitude of the two channels is superimposed; there is a certain probability that the synchronization signal can be solved.
  • the embodiment of the present application provides a method for channel scanning suitable for the DMR system and the DMR-PDT system.
  • the method can be applied to any one of the above systems. Communication equipment for channel scanning.
  • the method for channel scanning provided by an embodiment of the present application may include the following steps:
  • S101 Scan a current channel to obtain a signal of the current channel.
  • the current channel is any channel in the scan channel list.
  • the "signal" mentioned in the channel scanning method provided by any embodiment of the present application refers to performing the above-mentioned frequency conversion to a baseband signal, analog-to-digital conversion, and channel filtering on the directly received air interface signal,
  • the signal obtained after a series of operations such as FM demodulation, resampling, and root raised cosine (Root Raised Cosine) filtering. If the signal carries identifiable information, the signal is a valid signal, that is, a 4CPFSK signal. On the contrary, if the signal does not carry identifiable information (it is not originally carried, or it is carried but the information is distorted due to interference), Then the signal is called an invalid signal.
  • step S101 when step S101 is performed, the current channel may have a carrier signal or may not have a carrier signal. In other words, step S101 may be executed successfully, that is, the signal of the current channel is successfully obtained, or the execution may fail, that is, the current channel cannot be executed. get the signal.
  • the key of the method provided by the present application is how to quickly identify whether the signal on the channel is a valid signal. Therefore, in each embodiment, a signal exists in the current channel during scanning as an example for description.
  • step S107 may be directly executed.
  • S102 Calculate the maximum frequency offset envelope mean value of the signal of the current channel within the slicing time period after each slicing period.
  • the frequency offset is a common concept in the frequency shift keying technology (including the continuous phase frequency shift keying involved in this application, namely 4CPFSK), and is used to describe the amplitude of the frequency swing of the carrier modulated by this technology.
  • the signal obtained from the current channel is composed of multiple consecutive sampling points. For each sampling point, a frequency offset of the sampling point can be measured.
  • a frequency offset of the sampling point can be measured.
  • a set of frequency offset peak values (including positive and negative values) are generally set.
  • the frequency offset peak value is ⁇ 1.944kHz.
  • step S102 for a slice duration, it is possible to identify one by one whether the frequency offset of each sampling point of the signal obtained within this slice duration exceeds or reaches the frequency offset peak value, that is to say, identify the frequency offset of each sampling point. Whether the frequency offset is greater than or equal to 1.944kHz, or whether it is less than or equal to -1.944kHz, if the frequency offset of a sampling point is greater than or equal to 1.944kHz, or less than or equal to -1.944kHz, the sampling point is identified as this frequency offset. A peak point within the duration of the slice.
  • step S102 may be performed by measuring the frequency offset of each sampling point in real time, identifying whether each sampling point is a peak point based on the frequency offset, and then, every 2.5ms elapses , then average the frequency offsets of all peak points identified within the last 2.5ms to obtain the most recent 2.5ms, that is, the mean value of the maximum frequency offset envelope of the last segment.
  • the above-mentioned frequency offset requirement range can be specified by the digital mobile radio system. Specifically, the DMR protocol and the DMR-PDT protocol itself have a frequency offset requirement range set. In step S103, the maximum frequency offset envelope mean value can be directly determined Whether it is within the frequency offset requirement range set by the communication protocol.
  • step S102 and step S103 are executed in real time during the process of obtaining the signal from the current channel.
  • step S101 will be continuously performed, that is, the current channel will be continuously scanned to obtain the signal of the current channel.
  • step S104 can be executed.
  • step S105 may be executed.
  • the length of the fragmentation duration can be set according to the actual situation, for example, it can be set to 2.5ms.
  • the first duration is greater than the segment duration, and is shorter than the synchronization interval specified by the digital radio system.
  • the first duration can be set according to specific conditions. Generally, the first duration can be set to 70ms.
  • step S107 is executed; otherwise, if the scanning function is turned off, the current scanning is terminated, and the method ends.
  • Whether the scanning function is turned off can be manually determined by the user using the communication device by triggering a specific key. For example, after the user triggers the stop scanning key, the scanning function is turned off.
  • Whether the scanning function is turned off can also be determined by the communication device according to the preset scanning rules. For example, it can be set that if each channel in the scanning channel list is scanned once or N times (such as 3 times, 5 times), the scanning function is turned off. , you can set the cumulative running time of the scanning function to reach a certain length after this time, for example, the scanning function will be turned off when it reaches 20 seconds.
  • the communication device can determine in step S106 whether the current state of the device complies with the condition for turning off the scanning function set in the scanning rule. If so, the scanning function is automatically turned off, and the scanning function is judged to be turned off. It is determined that the scan function is not turned off, and step S107 is executed.
  • S107 Designate the next channel in the scan channel list as the current channel.
  • step S107 After the execution of step S107 is completed, it will return to step S101 to continue to scan the newly designated current channel.
  • the method provided by this embodiment on the premise that the scanning function is not turned off, will repeatedly scan each channel in the scanning channel list until a valid signal is identified on a certain channel. If the scanning function is turned off during the process, the method ends immediately, and the method is executed when the scanning function is enabled again.
  • the channel scanning method provided in this embodiment only needs to stay in the current channel for one segment at the earliest (if the duration of one segment is 2.5ms, it only needs to stay for 2.5ms) , it can be found that the maximum frequency offset envelope average value of this slice duration exceeds the frequency offset requirement range, and then immediately switches to the next channel for scanning. After 70ms), it is determined that the average value of the maximum frequency offset envelope of the last segment in the 70ms exceeds the required frequency offset range, and then switches to the next channel for scanning, that is, using the channel provided by this embodiment.
  • the scanning method can control the duration of staying on the channel to which the invalid signal belongs to within the range from the fragmentation duration to the first duration, while the prior art needs to stay for a synchronization interval, generally 360ms to determine the signal of the channel is an invalid signal.
  • this scheme detects whether the maximum frequency offset envelope mean value of the signal in each slice duration exceeds the frequency offset requirement range.
  • the signal of the current channel is an invalid signal, it only needs to stay in the current channel for one slice duration at the shortest.
  • the invalid signal can be identified within the time limit, and the invalid signal can be identified by staying on the current channel for the first time at the longest.
  • the walkie-talkie automatically generates a list of scanning channels based on the previous communication records, and the list contains multiple channels that need to be scanned next.
  • the walkie-talkie designates the first channel in the list as the current channel, and then performs the method described in the above embodiment on the current channel, assuming that the first channel does not have a carrier signal, that is, the walkie-talkie does not obtain a carrier signal from the first channel, so the walkie-talkie will go down.
  • One channel, ie, the second channel in the list, is designated as the current channel, and the above-described embodiment is performed again for the second channel.
  • the walkie-talkie After determining that there is a signal on the third channel, the walkie-talkie stays on the third channel and executes the method of the above embodiment. After the staying time reaches the first duration, each maximum frequency offset packet calculated by the walkie-talkie during this period of time The average value of the network is within the required frequency offset range, so it is judged that the signal of the third channel is a valid signal, and starts to communicate with the sender of the signal (which can be another walkie-talkie) on the third channel, and this scan ends.
  • another method for identifying valid signals can be introduced according to the symbol rate specified in the DMR system and the DMR-PDT system, and the method and the previous embodiment are based on the maximum frequency offset envelope mean methods are combined to improve accuracy.
  • a method for scanning channels provided by another embodiment of the present application may include the following steps:
  • S201 Scan a current channel to obtain a signal of the current channel.
  • S202 Calculate the maximum frequency offset envelope mean value of the signal of the current channel within the slice duration every time a segment passes.
  • step S209 is executed. If within the first duration, the mean value of the maximum frequency offset envelope of each slice duration does not exceed the frequency offset If it is not within the required range, step S207 is executed.
  • step S201 to step S203 is the same as that of step S101 to step S103, and will not be described in detail.
  • step S204 how to acquire the sampling point can be set according to the actual situation.
  • the first M eg, the first 1000 sampling points obtained from the most recent sampling of the signal of the current channel may be obtained, or each sampling point sampled from the start of scanning may be obtained in real time.
  • each sampling point can be measured to obtain a frequency offset, and the measured frequency offset is called the actual frequency offset of the sampling point.
  • the actual frequency offset of the sampling point can be calculated.
  • the difference between the offset and the standard frequency offset of the symbol to which the sampling point belongs, the result obtained is the frequency offset deviation of the sampling point.
  • the symbol rate it is possible to specify how long a period of signal takes to represent a symbol. For example, if the specified symbol rate is 4.8Ksymbol/s, that is, 4800 symbols per second, the corresponding signal every 1/4800 second is a symbol, and each sampling point sampled in a 1/4800 second belongs to this symbol sampling point.
  • sampling points can be obtained by sampling every 1/4800, and each corresponding symbol contains 5 sampling points.
  • the optimal sampling point can be determined.
  • the standard frequency offset corresponding to the range to which the decision value belongs that is, the standard frequency offset of this symbol.
  • the optimal sampling point in each symbol can be determined by various methods, such as determining the position of the optimal sampling point after frame synchronization.
  • the following provides a method for determining the optimal sampling point for each symbol without frame synchronization. :
  • each symbol contains 5 sampling points.
  • the first sampling point of each symbol is the best sampling point. Based on this, the frequency offset deviation of each sampling point is calculated to obtain a frequency offset deviation set. Assuming that the 2nd to 5th sampling points of each symbol are the optimal sampling points in turn, the frequency offset deviation sets corresponding to the 2nd to 5th sampling points are respectively calculated and obtained.
  • the frequency offset deviation valley value for each frequency offset deviation set, detect the frequency offset deviation valley value therein, so as to determine the number of frequency offset deviation valley values included in the frequency offset deviation set, that is, the number of valley values in the set, and use This number is subtracted from the expected number of valleys to obtain the number of valleys deviations for each frequency deviation set.
  • the expected number of valleys is a preset positive integer. For example, if it is expected that each symbol has a frequency offset deviation of one sampling point belonging to the frequency offset deviation valley, and 180 sampling points are obtained in step S204, which belong to If there are 36 symbols, then the expected number of valleys is 36.
  • the first step is to make the difference between the number of valleys in each frequency offset deviation set and 36 to obtain the deviation of the number of valleys.
  • the frequency offset deviation set with the smallest number of valleys and the next smallest frequency offset deviation set are selected, and for each of the two sets, each frequency offset deviation valley contained in the set is selected.
  • the position of the value is modulo N to obtain the modulo of each frequency offset deviation valley.
  • N refers to the number of sampling points contained in each symbol. When each symbol contains 5 sampling points, this step is to take modulo 5.
  • the position of the frequency offset deviation valley value refers to the sampling point corresponding to the frequency offset deviation valley value which is the number of sampling points obtained in step S204. For example, if the sampling point to which a certain frequency offset deviation valley value belongs is the 97th sampling point obtained in step S204 , the position of the frequency offset deviation valley value is 97 .
  • the frequency offset deviation set with the smallest number of valleys and the second smallest frequency deviation deviation set can be calculated to obtain multiple modulus, and then the set with the most modulus equal to m is determined as the optimal set.
  • the minimum frequency offset deviation set is determined as the optimal set.
  • the sampling point corresponding to the optimal set in each symbol can be designated as the optimal sampling point. For example, if the frequency offset deviation set obtained by taking the 4th sampling point of each symbol as the optimal sampling point is the optimal set, then the 4th sampling point of each symbol can be determined as the best sampling point of the symbol. best sampling point.
  • the frequency deviation valley value involved in the above process may refer to the frequency deviation deviation less than a certain threshold.
  • the threshold value can be set to 10 Hz. If a frequency deviation deviation is 9 Hz, it is determined that the frequency deviation deviation belongs to the frequency deviation deviation valley. value.
  • the vertical axis is the amplitude (the amplitude is proportional to the power), and the horizontal axis is the frequency.
  • step S206 is equivalent to judging whether the amplitude peak in the spectrum is located at the symbol rate.
  • step S206 is equivalent to judging whether the abscissa of the amplitude peak in the spectrum is 4800Hz.
  • step S207 is performed; otherwise, if the power peak value of the signal sequence is not located at the symbol rate, step S209 is performed.
  • the procedures from steps S204 to S206 can be executed simultaneously with the procedures from steps S202 to S203, that is, after staying on the current channel and scanning, the receiving end can follow the steps In the process from S202 to S203, the mean value of the maximum frequency deviation envelope of each slice duration is calculated one by one, and the judgment in S203 is performed.
  • the frequency deviation deviation of multiple sampling points can be collected, and the signal composed of these frequency deviation deviations can be detected. The power peak of the sequence, whether at the symbol rate.
  • step S208 is executed; otherwise, if at least one judgment result is negative, that is, the first judgment result is NO, or the second judgment result is NO , or if both the first judgment result and the second judgment result are negative, step S209 is executed.
  • the first judgment result refers to the judgment result of S203. If the average value of the maximum frequency deviation envelope calculated in any one slice duration exceeds the frequency deviation requirement range, the first judgment result is no. If the mean value of the maximum frequency offset envelope of the slice duration does not exceed the required frequency offset range, the first judgment result is yes.
  • the second judgment result refers to the judgment result of S206. If the power peak value of the signal sequence is at the symbol rate, the second judgment result is yes; otherwise, if the power peak value of the signal sequence is not at the symbol rate, the second judgment result is no.
  • Step S207 is equivalent to, if the power peak value of the signal sequence is located at the preset symbol rate of the digital mobile radio system, and the average value of each maximum frequency offset envelope calculated within the first time period is within the frequency offset requirement range, determine: The signal of the current channel is a valid signal.
  • steps S209 to S211 is the same as that of steps S105 to S107, and will not be repeated here.
  • step S211 ends, return to step S201 to continue scanning the newly designated current channel.
  • step S205 in order to reduce the computational resources consumed by performing the fast Fourier transform on the signal sequence, and at the same time improve the execution efficiency of the above-mentioned embodiment, before step S205 is performed, each frequency offset deviation obtained can be analyzed. Perform the following adjustment process:
  • a plurality of frequency deviation deviation valleys are identified in the obtained signal sequence composed of each frequency deviation deviation
  • the frequency offset deviation in the signal sequence that does not belong to the valley value of the frequency deviation deviation is set to zero to obtain the adjusted signal sequence.
  • the above adjustment is to judge one by one whether each frequency deviation in the signal sequence belongs to the valley of frequency deviation. If a frequency deviation belongs to the valley of frequency deviation, the current value of the frequency deviation is retained. The frequency deviation deviation does not belong to the frequency deviation deviation valley, so the frequency deviation deviation is set to 0.
  • the original step S205 is changed to perform fast Fourier transform on the adjusted signal sequence to obtain the spectrum of the adjusted signal sequence.
  • the original step S205 is changed to perform fast Fourier transform on the adjusted signal sequence to obtain the spectrum of the adjusted signal sequence.
  • Figure 3 is a schematic diagram of the spectrum of an adjusted signal sequence. It can be seen from Figure 3 that the position of the power peak in the spectrum is 4800Hz, which is consistent with the set symbol rate of 4800Symbol/s, that is, the power peak is located at the symbol rate. , and on this basis, if the first judgment result is yes, it can be determined that the signal of the corresponding channel is a valid signal.
  • the above-mentioned embodiment corresponding to FIG. 2 can solve the problem that only the maximum frequency offset envelope mean cannot distinguish between an effective relay signal and a single tone with modulation (and the single tone offset is exactly DMR).
  • the problem of the analog interference signal or the intermodulation interference signal with the maximum frequency offset), and the embodiment corresponding to FIG. 2 can more accurately identify the direct DMR signal compared with only using the maximum frequency offset envelope mean to distinguish the valid signal from the invalid signal .
  • Another embodiment of the present application also provides a method for channel scanning, please refer to FIG. 4 , the method may include the following steps:
  • S401 Scan the current channel to obtain the signal of the current channel.
  • S402 Calculate the maximum frequency offset envelope mean value of the signal of the current channel within the slice duration every time the segment passes.
  • step S408 is executed. If within the first duration, the mean value of the maximum frequency offset envelope of each slice duration does not exceed the frequency offset If it is not within the required range, step S406 is executed.
  • step S401 to step S403 is the same as that of step S101 to step S103, and will not be described in detail.
  • the detection of synchronization information in step S404 is consistent with the existing detection of synchronization information.
  • the synchronization pattern can be slidingly correlated with the received signal (that is, the signal of the current channel in the synchronization interval), (the synchronization pattern is also The first condition is satisfied when the sliding correlation result has a maximum value that can satisfy the set threshold. Then the position of the maximum value can know the start and end of the signal, and then perform symbol recovery of the signal, and then compare the recovered symbol with the expected synchronization word one by one to see if it is the expected synchronization word, if it can match, Synchronization information is considered to be detected.
  • the signal of the current channel in the synchronization interval refers to the carrier signal obtained from the current channel in a synchronization interval. If the synchronization interval is 360ms, step S404 is to detect a carrier signal with a duration of 360ms obtained from the current channel after starting to scan the current channel.
  • step S408 is performed, and if it is determined that the signal of the current channel within the synchronization interval carries synchronization information, step S407 is performed.
  • steps S402 to S403 and the processes described in steps S404 to S405 can also be executed in parallel, and are specifically consistent with the foregoing embodiment corresponding to FIG. 2 .
  • S406 Perform joint judgment on the first judgment result and the third judgment result.
  • the first judgment result refers to the judgment result of S403. If the average value of the maximum frequency deviation envelope calculated in any slice duration exceeds the frequency deviation requirement range, the first judgment result is no. If the mean value of the maximum frequency offset envelope of the slice duration does not exceed the required frequency offset range, the first judgment result is yes.
  • the third judgment result refers to the judgment result of S405. Specifically, if the signal of the current channel within the synchronization interval does not carry the synchronization information, the third judgment result is No. If the signal of the current channel within the synchronization interval carries the synchronization information, then the third judgment result is no. The judgment result is yes.
  • step S406 if both judgment results are yes, that is, the first judgment result and the third judgment result are both yes, then step S407 is executed, and if at least one judgment result is no, that is, the first judgment result and the third judgment result If any one of the results is negative or both of them are negative, step S408 is executed.
  • Step S406 is equivalent to, if the signal of the current channel contains synchronization information within the synchronization interval, and the average value of each maximum frequency offset envelope calculated within the first time period is within the required frequency offset range, determine that the signal of the current channel is: valid signal.
  • Steps S407 to S410 are the same as the corresponding steps in the foregoing embodiment, and will not be described in detail.
  • Combining the detection of synchronization information with the detection of the maximum frequency offset envelope mean value can also make up for the deficiency of only using the maximum frequency offset envelope mean value for detection, and improve the accuracy of the channel scanning method for identifying valid signals and invalid signals. .
  • the three methods for identifying valid signals and invalid signals include: identification based on the mean value of the maximum frequency offset envelope, identification based on symbol rate and power peak value, and identification based on synchronization information, which can be combined in the same embodiment.
  • the channel scanning method shown in Figure 5 is obtained:
  • S501 Scan the current channel to obtain the signal of the current channel.
  • step S502 is the process described in steps S202 to S203 in the foregoing embodiment corresponding to FIG. 2 , and details are not repeated here.
  • step S503 The specific execution process of step S503 is the same as the process described in steps S204 to S206 in the foregoing embodiment corresponding to FIG. 2 , and details are not repeated here.
  • step S504 The specific execution process of step S504 is consistent with steps S404 to S405 in the foregoing embodiment corresponding to FIG. 4 , and details are not described herein again.
  • the judgment result is NO
  • the judgment result is NO
  • step S506 is executed; otherwise, if the judgment result is no, step S507 is executed.
  • steps S502 to S504 may be performed in parallel.
  • step S509 is executed.
  • step S509 After the execution of step S509 is completed, return to the execution of step S501.
  • this embodiment uses the frequency offset, symbol rate, synchronization information and other characteristics to jointly determine the signals on each channel to be scanned, so as to quickly and accurately determine the signal on each channel to be scanned. Identify whether the signal of the current channel is a valid signal or an invalid signal.
  • the embodiment of the present application also provides a channel scanning device, please refer to FIG. 6 , the device may include:
  • the scanning unit 601 is configured to scan the current channel to obtain the signal of the current channel.
  • the current channel is any channel in the scan channel list.
  • the calculation unit 602 is configured to calculate the maximum frequency offset envelope mean value of the signal of the current channel within the fragmentation duration every time a segment passes, and determine whether the maximum frequency offset envelope mean value is within the preset frequency offset requirement range.
  • the determining unit 603 is configured to determine that the signal of the current channel is a valid signal if the average value of each maximum frequency offset envelope calculated within the first time period is within the required frequency offset range.
  • the first duration is greater than the segment duration and smaller than the preset synchronization interval.
  • the determining unit 603 is used to determine that the signal of the current channel is an invalid signal if any one of the maximum frequency offset envelope mean values calculated within the first time period is not within the frequency offset requirement range, and specify the next channel in the scanning channel list For the current channel, the trigger scanning unit 601 returns to perform scanning of the current channel.
  • the apparatus further includes a judgment unit 604 for:
  • the determining unit 603 is configured to, if the power peak value of the signal sequence is located at the preset symbol rate, and the average value of each maximum frequency offset envelope calculated within the first time period is within the frequency offset requirement range, determine the signal of the current channel is a valid signal.
  • the judging unit 605 is also used for:
  • a plurality of frequency deviation deviation valleys are identified in the obtained signal sequence composed of each frequency deviation deviation
  • the judging unit performs fast Fourier transform on the obtained signal sequence composed of each frequency offset deviation, and when obtaining the frequency spectrum of the signal sequence, the specific execution is as follows:
  • Fast Fourier transform is performed on the adjusted signal sequence to obtain the spectrum of the adjusted signal sequence.
  • the device further includes a detection unit 605 for:
  • the determining unit 603 is used to determine the signal of the current channel if the signal of the current channel contains synchronization information within the synchronization interval, and the average value of each maximum frequency offset envelope calculated within the first time period is within the required frequency offset range. is a valid signal.
  • the steps involved in joint decision in the foregoing embodiments may be performed by the determining unit 603 in the apparatus.
  • a device for channel scanning wherein the scanning unit 601 scans the current channel to obtain a signal of the current channel; wherein, the current channel is any channel in the scanning channel list; the calculating unit 602 calculates the time length of each fragment after passing through a fragment.
  • the maximum frequency offset envelope mean value of the signal of the current channel in the duration and determine whether the maximum frequency offset envelope mean value is within the preset frequency offset requirement range; the determining unit 603 is used for, if each calculated in the first duration
  • the mean value of the maximum frequency offset envelope is within the range of frequency offset requirements, and the signal of the current channel is determined to be a valid signal; wherein, the first duration is greater than the segment duration and less than the preset synchronization interval; if the calculated value within the first duration Any one of the maximum frequency offset envelope mean value, which is not within the frequency offset requirement range, determines that the signal of the current channel is an invalid signal, designates the next channel in the scan channel list as the current channel, and returns to execute the scan of the current channel.
  • An embodiment of the present application further provides a computer storage medium for storing a computer program, and when the computer program is executed, it is specifically used to implement the method for scanning a channel provided by any embodiment of the present application.
  • An embodiment of the present application further provides an electronic device, as shown in FIG. 7 , including a memory 701 and a processor 702 .
  • the memory 701 is used for storing computer programs.
  • the processor 702 is configured to execute the above computer program, and is specifically configured to implement the method for scanning channels provided by any embodiment of the present application.
  • the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions
  • the apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.
  • a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
  • processors CPUs
  • input/output interfaces network interfaces
  • memory volatile and non-volatile memory
  • Memory may include non-persistent memory in computer readable media, random access memory (RAM) and/or non-volatile memory in the form of, for example, read only memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.
  • RAM random access memory
  • ROM read only memory
  • flash RAM flash memory
  • Computer-readable media includes both persistent and non-permanent, removable and non-removable media, and storage of information may be implemented by any method or technology.
  • Information may be computer readable instructions, data structures, modules of programs, or other data.
  • Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Flash Memory or other memory technology, Compact Disc Read Only Memory (CD-ROM), Digital Versatile Disc (DVD) or other optical storage, Magnetic tape cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device.
  • computer-readable media does not include transitory computer-readable media, such as modulated data signals and carrier waves.
  • the embodiments of the present application may be provided as a method, a system or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.

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Abstract

本发明实施例提供一种信道扫描的方法、装置、设备和存储介质，方法包括，扫描当前信道，获得当前信道的信号；计算每一分片时长内信号的最大频偏包络均值，判断最大频偏包络均值是否在预设频偏要求范围内；若第一时长内计算得到的每一个最大频偏包络均值均在频偏要求范围内，确定信号有效；第一时长大于分片时长且小于预设同步间隔；若其中任一最大频偏包络均值不在频偏要求范围内，确定信号无效，继续扫描下一信道。本方案通过检测各分片时长内信号的最大频偏包络均值，最多在一个信道停留第一时长即可识别该信道的信号是否有效，缩短在无效信号所属信道上停留的时间，避免漏接有效信号。

Description

信道扫描的方法、装置、设备和存储介质 技术领域
本发明涉及通信技术领域，特别涉及一种信道扫描的方法、装置、设备和存储介质。
背景技术
在数字移动无线电(Digital Mobile Radio，DMR)系统中，当用户开启扫描功能时，期望能够切换多个信道监听到更多的呼叫。如果某些信道上存在干扰，能检测到上面有载波，则扫描就会停留在此信道上，持续检测一段预设时间内该信道上的信号，直至确认没有检测到有同步信息，再继续扫描下一信道。
现有的检测预设时间一般要大于有同步的最大间隔，例如DMR-PDT语音信号的同步间隔为360ms，则停留检测预设时间必须大于360ms。当此期间扫描列表里其他信道存在目标呼叫或数据信息时，容易导致漏接或呼叫掉字。
举例来讲，假定配置了扫描四个信道(C1-C4)，每个时隙依次切换配置的信道进行扫描。当扫描到信道C2，若C2上存在干扰，可在该信道上检测出RSSI和载波存在，就会停留在该信道一直进行接收，通过是否收到DMR-PDT的同步信息来判断是否收到业务。
而当DMR-PDT标准的同步间隔为语音同步时，360ms才会有一个同步信息。所以在C2信道需要停留至少360ms，才可以判断出确实不存在DMR-PDT业务，之后会再次启动对下一信道的扫描。
而在C2信道的停留期间，若C4信道发生业务，就会漏接C4信道前面一部分业务，导致前面部分信号的漏接。具体的，如果是短消息业务的话，会导致信号直接解析不出来；而如果是语音业务，前面发射的语音就会丢失(也就是语音掉字)。
发明内容
有鉴于此，本发明提供一种信道扫描的方法、装置、设备和存储介质，以避免信道扫描时漏接有效信号。
本申请第一方面提供一种信道扫描的方法，包括：
扫描当前信道，获得所述当前信道的信号；其中，所述当前信道是扫描信道列表中的任意一个信道；
每经过一个分片时长，计算在所述分片时长内所述当前信道的信号的最大频偏包络均值，并判断所述最大频偏包络均值，是否在预设频偏要求范围内；
若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号；其中，所述第一时长大于所述分片时长，并且小于预设同步间隔；
若在所述第一时长内计算得到的任意一个所述最大频偏包络均值，不在所述频偏要求范围内，确定所述当前信道的信号为无效信号，将所述扫描信道列表中的下一个信道指定为当前信道，返回执行所述扫描当前信道。
可选的，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号之前，还包括：
获取所述当前信道的信号中多个采样点的频偏偏差；
对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱；
基于所述频谱，判断所述信号序列的功率峰值是否位于预设符号速率处；
其中，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号，包括：
若所述信号序列的功率峰值位于所述符号速率处，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
可选的，所述对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱之前，还包括：
在获取的每一个所述频偏偏差组成的信号序列中识别得到多个频偏偏差谷值；
将所述信号序列中不属于所述频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列；
所述对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱，包括：
对所述调整后的信号序列进行快速傅里叶变换，得到所述调整后的信号序列的频谱。
可选的，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号之前，还包括：
对同步间隔内所述当前信道的信号进行同步信息检测；
其中，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号，包括：
若在所述同步间隔内所述当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
本申请第二方面提供一种信道扫描的装置，包括：
扫描单元，用于扫描当前信道，获得所述当前信道的信号；其中，所述当前信道是扫描信道列表中的任意一个信道；
计算单元，用于每经过一个分片时长，计算在所述分片时长内所述当前信道的信号的最大频偏包络均值，并判断所述最大频偏包络均值，是否在预设频偏要求范围内；
确定单元，用于若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号；其中，所述第一时长大于所述分片时长，并且小于预设同步间隔；
所述确定单元，用于若在所述第一时长内计算得到的任意一个所述最大频偏包络均值，不在所述频偏要求范围内，确定所述当前信道的信号为无效信号，将所述扫描信道列表中的下一个信道指定为当前信道，返回执行所述扫描当前信道。
可选的，所述装置还包括判断单元，用于：
获取所述当前信道的信号中多个采样点的频偏偏差；
对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱；
基于所述频谱，判断所述信号序列的功率峰值是否位于预设符号速率处；
所述确定单元用于，若所述信号序列的功率峰值位于所述符号速率处，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
可选的，所述判断单元还用于：
在获取的每一个所述频偏偏差组成的信号序列中识别得到多个频偏偏差谷值；
将所述信号序列中不属于所述频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列；
所述判断单元对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱时，具体执行：
对所述调整后的信号序列进行快速傅里叶变换，得到所述调整后的信号序列的频谱。
可选的，所述装置还包括检测单元，用于：
对同步间隔内扫描得到的当前信道的信号进行同步信息检测；
所述确定单元用于，若在所述同步间隔内所述当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
本申请第三方面提供一种电子设备，包括存储器和处理器；
其中，所述存储器用于存储计算机程序；
所述处理器用于执行所述计算机程序，具体用于实现本申请第一方面任意一项所提供的信道扫描的方法。
本申请第四方面提供一种计算机存储介质，用于存储计算机程序，所述计算机程序被执行时，具体用于实现本申请第一方面任意一项所提供的信道扫描的方法。
为实现上述目的，本发明实施例提供如下技术方案：
一种信道扫描的方法、装置、设备和存储介质，方法包括，扫描当前信道，获得当前信道的信号；其中，当前信道是扫描信道列表中的任意一个信道；每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值，并判断最大频偏包络均值，是否在预设频偏要求范围内；若在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号；其中，第一时长大于分片时长，并且小于预设同步间隔；若在第一时长内计算得到的任意一个最大频偏包络均值，不在频偏要求范围内，确定当前信道的信号为无效信号，将扫描信道列表中的下一个信道指定为当前信道，返回执行扫描当前信道。本方案通过检测各个分片时长内信号的最大频偏包络均值是否超出频偏要求范围，最多只需在当前信道停留第一时长即可识别出当前信道的信号是否有效，缩短了在无效信号所属信道上停留的时间，从而避免漏接有效信号。
上述说明仅是本发明技术方案的概述，为了能够更清楚了解本发明的技术手段，而可依照说明书的内容予以实施，并且为了让本发明的上述和其它目的、特征和优点能够更明显易懂，以下特举本发明的具体实施方式。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本发明的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1为本申请实施例提供的一种信道扫描的方法的流程图；
图2为本申请另一实施例提供的一种信道扫描的方法的流程图；
图3为本申请实施例提供的调整后的信号序列的频谱示意图；
图4为本申请又一实施例提供的一种信道扫描的方法的流程图；
图5为本申请再一实施例提供的一种信道扫描的方法的流程图；
图6为本申请实施例提供的一种信道扫描的装置的结构示意图；
图7为本申请实施例提供的一种电子设备的结构示意图。
具体实施方式
下面将参照附图更详细地描述本公开的示例性实施例。虽然附图中显示了本公开的示例性实施例，然而应当理解，可以以各种形式实现本公开而不应被这里阐述的实施例所限制。相反，提供这些实施例是为了能够更透彻地理解本公开，并且能够将本公开的范围完整的传达给本领域的技术人员。数字移动无线电(Digital Mobile Radio，DMR)，以及数字移动无线电及警用数字集群(Digital Mobile Radio-Police Digital Trunking，DMR-PDT)是无线通信领域的两种通信协议，通常应用于无线对讲机的通信，应用上述协议的多个无线对讲机构成的通信系统，相应的可以称为DMR系统，DMR-PDT系统等。
在DMR系统，以及DMR-PDT系统中，对信号的调制一般采用频移键控的方式进行，具体来说，在DMR-PDT系统中，发送端一般会采用4代连续相位频移键控技术(4 continuous phase frequency shift keying，4CPFSK)将需要发送的信息调制到载波信号上，得到携带信息的载波信号(由于采用4CPFSK技术调制，调制后携带有信息的载波信号也可以称为4CPFSK信号)，然后将4CPFSK信号通过某一信道进行广播，当任一接收端在广播时对该信道进行扫描，即可从该信道上获得上述携带信息的载波信号。
需要说明的是，发送端一般不会直接将上述4CPFSK信号向外发送，而是会对4CPFSK信号执行包括但不限于调频调制(Frequency Modulation，FM)数模转换，变频等后处理操作，最终获得空口信号，然后通过发送设备(如天线)将空口信号广播出去。
相应的，接收端通过扫描信道获得4CPFSK信号，实质上包括了如下流程：
扫描信道，从而接收到该信道上发送端广播的空口信号(一般是射频信号)，对空口信号进行变频，从而将空口信号变频到基带信号，然后对基带信号进行模数转换，使其转换为数字信号，再对数字信号进行信道滤波，FM解调，重采样，以及根升余弦(Root Raised Cosine)滤波，最终得到该信道上传输的4CPFSK信号。
如背景技术所述，接收端需要逐一扫描各个信道，才能确定出发送端是通过哪个信道发送的信号，而在扫描过程中，可能有某些信道上存在载波信号，但是该载波信号并未携带任何信息(或者原本携带的信息受信道 干扰而损坏)，在本申请中，将这类载波信号称为无效信号(或干扰信号)，相对的，携带发送端的信息的载波信号，则称为有效信号。
在扫描过程中，若当前扫描的信道(即当前信道)上没有载波信号，则接收端会立即切换至下一信道继续扫描，而在当前信道上有载波信号时，接收端则需要在当前信道上停留一定时长，持续扫描当前信道，以便识别出当前信道的载波信号具体是有效信号还是无效信号，是无效信号则继续扫描下一信道，是有效信号则开始和发送端通信。
显然，接收端若在无效信号的信道上停留过久，则可能错过另一信道上传输的有效信号，导致无法收到有效信号，或者收到后解读出的信息不完整，也就是发生背景技术所述的语音掉字或有效信号漏接。本申请所提供的信道扫描方案，其目的就在于尽可能缩短扫描过程中接收端在无效信号所属的信道上停留的时间，以避免发生语音掉字或有效信号漏接的情况。
在DMR-PDT系统中，常见的无效信号主要有模拟信道干扰信号，阻塞干扰信号和互调干扰信号几种，其中，模拟信道干扰信号解调后一般得到的是白噪声或无法识别的带噪声语音。
阻塞干扰信号又具体包括两种情况，第一种是强度较高的干扰信号和有效信号混合的阻塞干扰信号，当强度较高的干扰信号和有效信号同时被接收端接收时，强度较高的干扰信号会使接收端的非线性器件饱和，导致非线性器件产生非线性失真，使有效信号失真。第二种情况是强度过高(指高于接收端的器件的工作范围)的有效信号，有效信号的强度过高会产生振幅压缩现象，同样会导致有效信号失真。
互调干扰信号，具体又可以分为模拟互调干扰信号，数字直通互调干扰信号，和数字中转互调干扰信号三种。
其中，模拟互调干扰，解调后的信号特征与模拟信道干扰一致，表现为白噪声和带噪语音。
数字直通互调，解调后的信号特征表现为：信号交叠的部分4CPFSK频偏变大的信号，非交叠部分无载波，是一个非对称占空比的60ms周期信号；有一定概率能解出同步信号。
数字中转互调解调后的信号特征表现为：信号的频偏整体变大，是两路信道振幅叠加后的信号；有一定概率能解出同步信号。
针对DMR系统，DMR-PDT系统中可能存在的上述无效信号，本申请实施例提供一种适用于DMR系统，DMR-PDT系统的信道扫描的方法，该方法可以适用于以上系统中任意一个需要进行信道扫描的通信设备。
请参考图1，本申请的一个实施例所提供的信道扫描的方法可以包括如下步骤：
S101、扫描当前信道，获得当前信道的信号。
其中，当前信道是扫描信道列表中的任意一个信道。
本申请任一实施例所提供的信道扫描的方法中所提及的“信号”，均指代对直接收到的空口信号执行了前文所述的变频为基带信号，模数转换，信道滤波，FM解调，重采样，以及根升余弦(Root Raised Cosine)滤波等一系列操作后得到的信号。若该信号携带有可识别的信息，则该信号属于有效信号，即4CPFSK信号，反之，若该信号未携带有可识别的信息(原本就未携带，或者携带了但是信息因干扰而失真)，则该信号称为无效信号。
可以理解的，在执行步骤S101时，当前信道可能有载波信号，也可能没有载波信号，换言之，步骤S101可能执行成功，即成功获得当前信道的信号，也可能执行失败，即未能在当前信道获得信号。本申请所提供的方法关键在于如何快速的识别出信道上的信号是否为有效信号，因此各实施例中均以扫描时当前信道存在信号为例进行说明。
在实际的应用场景中，若未能从当前信道获得信号，即通过扫描发现当前信道没有载波信号，那么可以直接将扫描信道列表中的下一个信道指定为当前信道，然后继续扫描新指定的这个当前信道。也就是说，在本实施例中，若S101中未获得当前信道的信号，则可以直接执行步骤S107。
S102、每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值。
频偏，是频移键控技术(包括本申请所涉及的连续相位频移键控，即4CPFSK)中通用的一个概念，用于描述采用该技术调制后的载波的频率摆动的幅度。
从当前信道获得的信号，由连续的多个采样点组成，针对每一个采样点，均可以测量得到该采样点的一个频偏，具体的测量方法可以参考相关的现有技术，此处不再详述。
在DMR协议，DMR-PDT协议中，一般会设定一组频偏峰值(包含正值和负值)，如DMR-PDT协议中，频偏峰值为±1.944kHz。
在步骤S102中，对于一个分片时长，可以逐一识别在这一分片时长内获得的信号的每一个采样点的频偏是否超过或达到频偏峰值，也就是说，识别每一个采样点的频偏是否大于或等于1.944kHz，或者是否小于或等于-1.944kHz，若某一采样点的频偏大于或等于1.944kHz，或者小于或等于-1.944kHz，就将这一采样点识别为这个分片时长内的一个峰值点。
最后，对这个分片时长内识别得到的所有峰值点的频偏取平均，得到的结果，就是这一分片时长内，当前信道的信号的最大频偏包络均值。
举例来说，设分片时长为2.5ms，则步骤S102的执行方式可以是，实时测量每一采样点的频偏，基于频偏识别每一采样点是否为峰值点，然后，每经过2.5ms，就将最近这2.5ms内识别得到的所有峰值点的频偏取平均，得到最近这2.5ms，也就是刚过去的这一个分片时长的最大频偏包络均值。
S103、判断最大频偏包络均值是否在频偏要求范围内。
上述频偏要求范围，可以由数字移动无线电系统指定的，具体来说，DMR协议，DMR-PDT协议本身就设定有频偏要求范围，在步骤S103中，可以直接判断最大频偏包络均值是否在通信协议所设定的频偏要求范围内。
需要说明的是，步骤S102和步骤S103是在从当前信道获得信号的过程中实时执行的。当发现当前信道存在信号时，步骤S101会持续执行，即持续地对当前信道进行扫描以获得当前信道的信号，与此同时，每经过一个分片时长，就会执行一次S102，对最近的这一个分片时长内从当前信道获得的信号计算其最大频偏包络均值，然后立即判断计算出的最大频偏包络均值是否在频偏要求范围内。
一旦发现某一次计算得到的一个最大频偏包络均值不在频偏要求范围内，则可以执行步骤S104，反之，若以对当前信道的扫描的开始时刻为起点，经过预设的第一时长之后，这段时间内计算得到的每一个最大频偏包络均值均在频偏要求范围内，则可以执行步骤S105。
分片时长的长短可以根据实际情况设定，例如可以设置为2.5ms。
S104、确定当前信道的信号为有效信号。
其中，第一时长大于分片时长，并且小于数字无线电系统指定的同步间隔。
第一时长可以根据具体情况设定，一般的，第一时长可以设置为70ms。
S105、确定当前信道的信号为无效信号。
S106、判断扫描功能是否关闭。
若扫描功能未关闭，则执行步骤S107，反之，若扫描功能关闭，则本次扫描终止，本方法结束。
扫描功能是否关闭，可以由使用通信设备的用户通过触发特定按键的方式手动决定，如用户触发停止扫描按键后，扫描功能关闭。
扫描功能是否关闭也可以由通信设备按预设的扫描规则决定，例如，可以设定若扫描信道列表中每一个信道均被扫描了一次或N次(如3次，5次)之后扫描功能关闭，可以设定扫描功能本次启用后累计运行时间达到特定时长，如达到20秒时扫描功能关闭。此时，通信设备可以在步骤S106中判断设备当前的状态是否符合扫描规则中设定的关闭扫描功能的条件，如符合，则自动关闭扫描功能，并判断出扫描功能关闭，如不符合，则判断出扫描功能未关闭，执行步骤S107。
S107、将扫描信道列表中的下一个信道指定为当前信道。
步骤S107执行结束后，将返回步骤S101，继续对新指定的这个当前信道进行扫描。
可以看出，本实施例所提供的方法，在扫描功能未关闭的前提下，将反复对扫描信道列表中的各个信道进行扫描，直至在某一个信道上识别到有效信号才终止，若在扫描过程中扫描功能关闭，则立即结束本方法，当再次启用扫描功能时再执行本方法。
若当前信道的信号是无效信号，通过本实施例所提供的信道扫描的方法，最快只需在当前信道停留一个分片时长(若一个分片时长为2.5ms，则只需停留2.5ms)，就可以发现这一个分片时长的最大频偏包络均值超出频偏要求范围，然后立即切换至下一个信道进行扫描，在最差的情况下，也可以在停留了第一时长(如停留了70ms)之后，确定出这70ms内的最后一个分片时长的最大频偏包络均值超出频偏要求范围，进而切换至下一信道进行扫描，也就是说，利用本实施例所提供的信道扫描方法，可以将在无效信号所属信道上停留的时长，控制在分片时长至第一时长这一范围 内，而现有技术需要停留一个同步间隔，一般是停留360ms才能判断出该信道的信号是无效信号。
综上所述，本方案通过检测各个分片时长内信号的最大频偏包络均值是否超出频偏要求范围，在当前信道的信号是无效信号时，最短只需在当前信道停留一个分片时长的时间即可识别出无效信号，最长也只需在当前信道停留第一时长即可识别出无效信号，显著缩短了在无效信号所属信道上停留的时间，从而避免漏接有效信号。
下面举例说明上述实施例的一个具体应用场景：
假设某一时刻用户开启了对讲机的扫描功能，然后，对讲机根据以往的通信记录，自动生成了一个扫描信道列表，列表中包含多个接下来需要扫描的信道。
对讲机将列表中的首个信道指定为当前信道，然后对当前信道执行上述实施例所述的方法，假设首个信道不存在载波信号，即对讲机未从首个信道获得载波信号，于是对讲机将下一个信道，即列表中的第二个信道指定为当前信道，对第二个信道再次执行上述实施例。
第二个信道存在信号，对讲机在第二个信道停留了10个分片时长的时间(即25ms)后，发现第10个分片时长内计算得到的最大频偏包络均值超出频偏要求范围，于是判断出第二个信道的信号为无效信号，指定列表中的下一信道，即指定第三个信道为当前信道。
确定出第三个信道存在信号后，对讲机在第三个信道停留并执行上述实施例的方法，在停留的时间达到第一时长之后，对讲机在这段时间内计算得到的每一个最大频偏包络均值均在频偏要求范围内，于是判断出第三个信道的信号为有效信号，开始在第三个信道上和信号的发送端(可以是另一个对讲机)进行通信，本次扫描结束。
在本申请的另一实施例中，可以根据DMR系统，DMR-PDT系统中规定的符号速率，引入另一种识别有效信号的方法，将该方法和前述实施例中基于最大频偏包络均值的方法结合，以提高准确性。
请参考图2，本申请另一实施例所提供的扫描信道的方法，可以包括如下步骤：
S201、扫描当前信道，获得当前信道的信号。
S202、每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值。
S203、判断最大频偏包络均值是否在频偏要求范围内。
若任意一个分片时长内计算得到的最大频偏包络均值超出频偏要求范围，则执行步骤S209，若在第一时长内，每一个分片时长的最大频偏包络均值均不超出频偏要求范围，则执行步骤S207。
步骤S201至步骤S203的执行过程，和步骤S101至步骤S103一致，不再详述。
S204、获取当前信道的信号中多个采样点的频偏偏差。
步骤S204中，具体如何获取采样点可以根据实际情况设置。如可以获取从当前信道的信号最近采样得到的前M个(如前1000个)采样点，或者可以实时的获取从开始扫描时采样得到的每一个采样点。
如前文所述，每一个采样点均可以测量得到一个频偏，这个测量得到的频偏称为该采样点的实际频偏，相应的，对于每一个采样点，可以计算这个采样点的实际频偏和这个采样点所属符号的标准频偏之间的差值，得到的结果就是这个采样点的频偏偏差。
在DMR系统，DMR-PDT系统中，可以通过设定符号速率的方式，指定用多长时间的一段信号来表示一个符号。例如，指定符号速率为4.8Ksymbol/s，即每秒4800个符号，相应的每1/4800秒的信号，就是一个符号，在一个1/4800秒内采样得到的各个采样点，就是属于这个符号的采样点。
例如当采样率时24kHz时，每1/4800可以采样得到5个采样点，对应的每个符号就包含5个采样点。
一个符号的标准频偏可以按如下方式确定：
首先在该符号包含的所有采样点中确定一个最佳采样点，然后对这个最佳采样点进行判决，得到最佳采样点的判决值，根据最佳采样点的判决值，就可以确定出该判决值所属的范围对应的标准频偏，也就是这个符号的标准频偏。
每个符号中的最佳采样点可以采用多种方法确定，如进行帧同步之后确定最佳采样点的位置，下面提供一种不需要帧同步即可确定每个符号的最佳采样点的方法：
首先，分别假设每个符号中的第i个采样点为最佳采样点，然后基于假设的最佳采样点对各个采样点计算对应的频偏偏差，i是1至N范围内的整数，N为每个符号包含的采样点的数量。
结合前述例子，每个符号包含5个采样点，首先假设每个符号的第1个采样点为最佳采样点，基于此计算每个采样点的频偏偏差，得到一个频偏偏差集合，同理，依次假设每个符号的第2个至第5个采样点为最佳采样点，分别计算得到第2个采样点至第5个采样点对应的频偏偏差集合。
然后，第一方面，对每一频偏偏差集合，检测其中的频偏偏差谷值，从而确定出该频偏偏差集合包含的频偏偏差谷值的数量，即该集合的谷值数量，并用这一数量和期望谷值数量作差，得到每一频偏偏差集合的谷值数量偏差。
其中，期望谷值数量是一个预设的正整数，例如，若预计每一个符号均有一个采样点的频偏偏差属于频偏偏差谷值，且步骤S204中获得了180个采样点，分别属于36个符号，那么期望谷值数量就是36，第一方面的步骤就是将每一频偏偏差集合的谷值数量和36作差，得到谷值数量偏差。
第二方面，选取第一方面中，谷值数量偏差最小的频偏偏差集合和次小的频偏偏差集合，针对这两个集合中的每一个，将该集合包含的每个频偏偏差谷值的位置对N取模，得到每个频偏偏差谷值的模数。N指每个符号包含的采样点的数量，当每个符号包含5个采样点时，该步骤就是对5取模。
其中，频偏偏差谷值的位置，是指，这个频偏偏差谷值所对应的采样点是步骤S204中获得的第几个采样点。比如，某个频偏偏差谷值所属的采样点是步骤S204中获得的第97个采样点，则这个频偏偏差谷值的位置就是97。
通过上述计算，谷值数量偏差最小的频偏偏差集合和次小的频偏偏差集合均可以计算得到多个模数，然后将其中等于m的模数最多的那个集合确定为最优集合。m是一个根据N设定的整数，当N为偶数时，m＝N/2，当N为奇数时，m＝(N+1)/2，例如，N等于5时，m等于3，相应的，上述步骤就是，将两个频偏偏差集合中，有最多的等于3的模数的集合确定为最优集合。
例如，谷值数量偏差最小的频偏偏差集合中有20个模数等于3，谷值数量偏差次小的频偏偏差集合中有15个模数等于3，就将前者，即谷值数量偏差最小的频偏偏差集合确定为最优集合。
确定了最优集合后，就可以将每个符号中最优集合对应的采样点指定为最佳采样点。例如，若以每个符号的第4个采样点作为最佳采样点而得到的频偏偏差集合是最优集合，那么，就可以将每个符号的第4个采样点确定为该符号的最佳采样点。
上述过程中涉及的频偏偏差谷值，可以是指小于一定阈值的频偏偏差，例如，可以设定阈值为10Hz，若一个频偏偏差为9Hz，就确定该频偏偏差属于频偏偏差谷值。
S205、对获取的每一个频偏偏差组成的信号序列进行快速傅里叶变换，得到信号序列的频谱。
快速傅里叶变换后得到的频谱，其纵轴为幅度(幅度和功率成正比)，横轴为频率。
S206、判断信号序列的功率峰值是否位于符号速率处。
功率和幅度成正比，因此步骤S206相当于判断频谱中的幅度峰值是否位于符号速率处。
例如，假设符号速率为4800Symbol/s，那么步骤S206相当于，判断频谱中幅度峰值所在的横坐标是否为4800Hz。
若信号序列的功率峰值位于符号速率处，则执行步骤S207，反之，若信号序列的功率峰值不位于符号速率处，则执行步骤S209。
需要说明的是，步骤S204至步骤S206所述的流程，可以和步骤S202至步骤S203所述的流程同时执行，也就是说，当停留在当前信道并进行扫描之后，接收端一方面可以按步骤S202至S203的过程，逐一计算每一个分片时长的最大频偏包络均值，并进行S203的判断，另一方面可以采集多个采样点的频偏偏差，并检测这些频偏偏差组成的信号序列的功率峰值，是否在符号速率处。
S207、对第一判断结果和第二判断结果进行联合判决。
若两个判断结果，即第一判断结果和第二判断结果均为是，则执行步骤S208，反之，若至少一个判断结果为否，即第一判断结果为否，或者第 二判断结果为否，或者第一判断结果和第二判断结果均为否，则执行步骤S209。
第一判断结果是指S203的判断结果，若任意一个分片时长内计算得到的最大频偏包络均值超出频偏要求范围，则第一判断结果为否，若在第一时长内，每一个分片时长的最大频偏包络均值均不超出频偏要求范围，则第一判断结果为是。
第二判断结果是指S206的判断结果，若信号序列的功率峰值位于符号速率处，则第二判断结果为是，反之若信号序列的功率峰值不在符号速率处，则第二判断结果为否。
步骤S207相当于，若信号序列的功率峰值位于数字移动无线电系统预设的符号速率处，并且在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号。
S208、确定当前信道的信号为有效信号。
S209、确定当前信道的信号为无效信号。
S210、判断扫描功能是否关闭。
S211、将扫描信道列表中的下一个信道指定为当前信道。
步骤S209至步骤S211的具体执行过程，和步骤S105至S107一致，不再赘述。
步骤S211结束后，返回执行步骤S201，以便继续扫描新指定的当前信道。
进一步的，在步骤S205中，为了减小对信号序列进行快速傅里叶变换所消耗的计算资源，同时提高上述实施例的执行效率，可以在执行步骤S205之前，对获取到的各个频偏偏差执行如下的调整过程：
在获取的每一个频偏偏差组成的信号序列中识别得到多个频偏偏差谷值；
将信号序列中不属于频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列。
具体来说，上述调整就是，逐一判断信号序列中每一个频偏偏差是否属于频偏偏差谷值，若一个频偏偏差属于频偏偏差谷值，则保留该频偏偏差当前的数值，若一个频偏偏差不属于频偏偏差谷值，就将这个频偏偏差设置为0。
相应的，原本的步骤S205就变更为，对调整后的信号序列进行快速傅里叶变换，得到调整后的信号序列的频谱。后续判断功率峰值是否在符号速率处时，就是判断调整后的信号序列的功率峰值是否在符号速率处。
图3是一个调整后的信号序列的频谱的示意图，从图3可以看出，频谱中的功率峰值所在的位置为4800Hz，和设定的符号速率4800Symbol/s一致，即功率峰值位于符号速率处，在此基础上，若第一判断结果为是，则可以确定对应的信道的信号为有效信号。
与图1对应的实施例相比，前述图2对应的实施例，可以很好的解决仅使用最大频偏包络均值无法区分有效中转信号与带调制单音(且该单音频偏正好为DMR最大频偏)的模拟干扰信号或互调干扰信号的问题，并且，与仅使用最大频偏包络均值区分有效信号和无效信号相比，图2对应的实施例能够更准确的识别直通DMR信号。
本申请又一实施例还提供一种信道扫描的方法，请参考图4，该方法可以包括如下步骤：
S401、扫描当前信道，获得当前信道的信号。
S402、每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值。
S403、判断最大频偏包络均值是否在频偏要求范围内。
若任意一个分片时长内计算得到的最大频偏包络均值超出频偏要求范围，则执行步骤S408，若在第一时长内，每一个分片时长的最大频偏包络均值均不超出频偏要求范围，则执行步骤S406。
步骤S401至步骤S403的执行过程，和步骤S101至步骤S103一致，不再详述。
S404、对同步间隔内当前信道的信号进行同步信息检测。
步骤S404中对同步信息的检测，和现有的对同步信息的检测一致，一般情况下，可以将同步图样与接收的信号(即同步间隔内当前信道的信号)进行滑动相关，(同步图样也是用标准规定的一串符号进行波形成型的方法产生)当滑动相关的结果有个最大值能满足设置的门限时，满足了第一个条件。然后最大值的位置可以知道该信号的起止，然后再将该信号 进行符号恢复，再将恢复的符号与期待的同步字一一比对，看是否为期望接收的同步字，如果能匹配上，则认为检测到同步信息。
同步间隔内当前信道的信号，就是指，在一个同步间隔内，从当前信道获得的载波信号。如同步间隔为360ms，则步骤S404就是，检测在开始扫描当前信道后，从当前信道获得的时长360ms的载波信号。
S405、判断同步间隔内当前信道的信号是否携带同步信息。
若判断出同步间隔内当前信道的信号未携带同步信息，则执行步骤S408，若判断出同步间隔内当前信道的信号携带同步信息，则执行步骤S407。
步骤S402至S403所述的流程，和步骤S404至S405所述的流程，同样可以并行执行，具体和前述图2对应的实施例一致。
S406、对第一判断结果和第三判断结果进行联合判决。
第一判断结果是指S403的判断结果，若任意一个分片时长内计算得到的最大频偏包络均值超出频偏要求范围，则第一判断结果为否，若在第一时长内，每一个分片时长的最大频偏包络均值均不超出频偏要求范围，则第一判断结果为是。
第三判断结果是指S405的判断结果，具体的，若同步间隔内当前信道的信号未携带同步信息，则第三判断结果为否，若同步间隔内当前信道的信号携带同步信息，则第三判断结果为是。
在步骤S406中，若两个判断结果均为是，即第一判断结果和第三判断结果均为是，则执行步骤S407，若至少一个判断结果为否，即第一判断结果和第三判断结果中任意一个为否或者两个均为否，则执行步骤S408。
步骤S406相当于，若在同步间隔内当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号。
S407、确定当前信道的信号为有效信号。
S408、确定当前信道的信号为无效信号。
S409、判断扫描功能是否关闭。
S410、将扫描信道列表中的下一个信道指定为当前信道。
步骤S407至S410，和前述实施例的对应步骤一致，不再详述。
将对同步信息的检测和对最大频偏包络均值的检测结合，同样能够弥补仅使用最大频偏包络均值进行检测的不足，提高信道扫描的方法对有效信号和无效信号的识别的准确度。
最后，上述各个实施例所提供的三种识别有效信号和无效信号的方法，包括，基于最大频偏包络均值识别，基于符号速率和功率峰值识别，基于同步信息识别，可以合并在同一实施例中，得到如图5所示的信道扫描方法：
S501、扫描当前信道，获得当前信道的信号。
S502、基于每一分片时长的最大频偏包络均值检测当前信道的信号，得到第一判断结果。
步骤S502的具体执行过程，就是前述图2对应的实施例中步骤S202至S203所述的过程，此处不再赘述。
S503、基于多个频偏偏差组成的信号序列的频谱检测当前信道的信号，得到第二判断结果。
步骤S503的具体执行过程，与前述图2对应的实施例中步骤S204至S206所述的过程一致，此处不再赘述。
S504、基于同步信息检测当前信道的信号，得到第三判断结果。
步骤S504的具体执行过程，与前述图4对应的实施例中步骤S404至S405一致，此处不再赘述。
S505、对第一、第二和第三判断结果进行联合判决，得到判决结果。
第一判断结果，第二判断结果和第三判断结果的含义请参考前述实施例，此处不再详述。
步骤S505所述的联合判决中，三个判断结果和最终的判决结果的关系如表1所示：
表1
Figure PCTCN2021082910-appb-000001
Figure PCTCN2021082910-appb-000002
具体来说，当第一判断结果为是时，第二判断结果和第二判断结果中只要有至少一项为是，则最后的判决结果为是；当第一判断结果为是，而第二判断结果和第三判断结果均为否时，判决结果为否，当第一判断结果为否时，不论第二判断结果和第三判断结果如何，判决结果均为否。
判决结果为是，则执行步骤S506，反之，判决结果为否，则执行步骤S507。
步骤S502至S504所述的三个检测过程可以并行执行。
S506、确定当前信道的信号为有效信号。
S507、确定当前信道的信号为无效信号。
S508、判断扫描功能是否关闭。
若扫描功能关闭，则本方法结束，若扫描功能未关闭，执行步骤S509。
S509、将扫描信道列表中的下一个信道指定为当前信道。
步骤S509执行完毕后，返回执行步骤S501。
本实施例针对DMR系统，DMR-PDT系统中干扰信号(无效信号)的特征，利用频偏，符号速率，同步信息等特征对需要扫描的各信道上的信号进行联合判决，从而快速且准确的识别出当前信道的信号是有效信号还是无效信号。
结合本申请实施例提供的信道扫描的方法，本申请实施例还提供一种信道扫描的装置，请参考图6，该装置可以包括：
扫描单元601，用于扫描当前信道，获得当前信道的信号。
其中，当前信道是扫描信道列表中的任意一个信道。
计算单元602，用于每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值，并判断最大频偏包络均值，是否在预设频偏要求范围内。
确定单元603，用于若在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号。
其中，第一时长大于分片时长，并且小于预设同步间隔。
确定单元603，用于若在第一时长内计算得到的任意一个最大频偏包络均值，不在频偏要求范围内，确定当前信道的信号为无效信号，将扫描信道列表中的下一个信道指定为当前信道，触发扫描单元601返回执行扫描当前信道。
可选的，该装置还包括判断单元604，用于：
获取当前信道的信号中多个采样点的频偏偏差；
对获取的每一个频偏偏差组成的信号序列进行快速傅里叶变换，得到信号序列的频谱；
基于频谱，判断信号序列的功率峰值是否位于预设符号速率处；
确定单元603用于，若信号序列的功率峰值位于预设符号速率处，并且在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号。
可选的，判断单元605还用于：
在获取的每一个频偏偏差组成的信号序列中识别得到多个频偏偏差谷值；
将信号序列中不属于频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列；
判断单元对获取的每一个频偏偏差组成的信号序列进行快速傅里叶变换，得到信号序列的频谱时，具体执行：
对调整后的信号序列进行快速傅里叶变换，得到调整后的信号序列的频谱。
可选的，该装置还包括检测单元605，用于：
对同步间隔内扫描得到的当前信道的信号进行同步信息检测；
确定单元603用于，若在同步间隔内当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号。
前述实施例中涉及联合判决的步骤，可以由该装置中的确定单元603执行。
本申请实施例所提供的扫描信道的装置，其具体工作原理可以参考本申请任一实施例所提供的扫描信道的方法中的相关步骤，此处不再赘述。
一种信道扫描的装置，其中，扫描单元601扫描当前信道，获得当前信道的信号；其中，当前信道是扫描信道列表中的任意一个信道；计算单元602每经过一个分片时长，计算在分片时长内当前信道的信号的最大频偏包络均值，并判断最大频偏包络均值，是否在预设频偏要求范围内；确定单元603用于，若在第一时长内计算得到的每一个最大频偏包络均值，均在频偏要求范围内，确定当前信道的信号为有效信号；其中，第一时长大于分片时长，并且小于预设同步间隔；若在第一时长内计算得到的任意一个最大频偏包络均值，不在频偏要求范围内，确定当前信道的信号为无效信号，将扫描信道列表中的下一个信道指定为当前信道，返回执行扫描当前信道。本方案通过检测各个分片时长内信号的最大频偏包络均值是否超出频偏要求范围，最多只需在当前信道停留第一时长即可识别出当前信道的信号是否有效，缩短了在无效信号所属信道上停留的时间，从而避免漏接有效信号。
本申请实施例还提供一种计算机存储介质，用于存储计算机程序，该计算机程序被执行时，具体用于实现本申请任一实施例所提供的扫描信道的方法。
本申请实施例还提供一种电子设备，如图7所示，包括存储器701和处理器702。
其中，存储器701用于存储计算机程序。
处理器702用于执行上述计算机程序，具体用于实现本申请任一实施例所提供的扫描信道的方法。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图 中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
在一个典型的配置中，计算设备包括一个或多个处理器(CPU)、输入/输出接口、网络接口和内存。
存储器可能包括计算机可读介质中的非永久性存储器，随机存取存储器(RAM)和/或非易失性内存等形式，如只读存储器(ROM)或闪存(flash RAM)。存储器是计算机可读介质的示例。
计算机可读介质包括永久性和非永久性、可移动和非可移动媒体可以由任何方法或技术来实现信息存储。信息可以是计算机可读指令、数据结构、程序的模块或其他数据。计算机的存储介质的例子包括，但不限于相变内存(PRAM)、静态随机存取存储器(SRAM)、动态随机存取存储器(DRAM)、其他类型的随机存取存储器(RAM)、只读存储器(ROM)、电可擦除可编程只读存储器(EEPROM)、快闪记忆体或其他内存技术、只读光盘只读存储器(CD-ROM)、数字多功能光盘(DVD)或其他光学存储、磁盒式磁带，磁带磁磁盘存储或其他磁性存储设备或任何其他非传输介质，可用于存储可以被计算设备访问的信息。按照本文中的界定，计算机可读介质不包括暂存电脑可读媒体(transitory media)，如调制的数据信号和载 波。
还需要说明的是，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、商品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、商品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括要素的过程、方法、商品或者设备中还存在另外的相同要素。
本领域技术人员应明白，本申请的实施例可提供为方法、系统或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
以上仅为本申请的实施例而已，并不用于限制本申请。对于本领域技术人员来说，本申请可以有各种更改和变化。凡在本申请的精神和原理之内所作的任何修改、等同替换、改进等，均应包含在本申请的权利要求范围之内。

Claims (10)

  1. 一种信道扫描的方法，其特征在于，包括：
    扫描当前信道，获得所述当前信道的信号；其中，所述当前信道是扫描信道列表中的任意一个信道；
    每经过一个分片时长，计算在所述分片时长内所述当前信道的信号的最大频偏包络均值，并判断所述最大频偏包络均值是否在预设频偏要求范围内；
    若在第一时长内计算得到的每一个所述最大频偏包络均值均在所述频偏要求范围内，确定所述当前信道的信号为有效信号；其中，所述第一时长大于所述分片时长，并且小于预设同步间隔；
    若在所述第一时长内计算得到的任意一个所述最大频偏包络均值，不在所述频偏要求范围内，确定所述当前信道的信号为无效信号，将所述扫描信道列表中的下一个信道指定为当前信道，返回执行所述扫描当前信道。
  2. 根据权利要求1所述的方法，其特征在于，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号之前，还包括：
    获取所述当前信道的信号中多个采样点的频偏偏差；
    对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱；
    基于所述频谱，判断所述信号序列的功率峰值是否位于预设符号速率处；
    其中，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号，包括：
    若所述信号序列的功率峰值位于所述符号速率处，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
  3. 根据权利要求2所述的方法，其特征在于，所述对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱之前，还包括：
    在获取的每一个所述频偏偏差组成的信号序列中识别得到多个频偏偏 差谷值；
    将所述信号序列中不属于所述频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列；
    所述对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱，包括：
    对所述调整后的信号序列进行快速傅里叶变换，得到所述调整后的信号序列的频谱。
  4. 根据权利要求1所述的方法，其特征在于，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号之前，还包括：
    对同步间隔内所述当前信道的信号进行同步信息检测；
    其中，所述若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号，包括：
    若在所述同步间隔内所述当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
  5. 一种信道扫描的装置，其特征在于，包括：
    扫描单元，用于扫描当前信道，获得所述当前信道的信号；其中，所述当前信道是扫描信道列表中的任意一个信道；
    计算单元，用于每经过一个分片时长，计算在所述分片时长内所述当前信道的信号的最大频偏包络均值，并判断所述最大频偏包络均值是否在预设频偏要求范围内；
    确定单元，用于若在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号；其中，所述第一时长大于所述分片时长，并且小于预设同步间隔；
    所述确定单元，用于若在所述第一时长内计算得到的任意一个所述最大频偏包络均值，不在所述频偏要求范围内，确定所述当前信道的信号为无效信号，将所述扫描信道列表中的下一个信道指定为当前信道，返回执行所述扫描当前信道。
  6. 根据权利要求5所述的装置，其特征在于，所述装置还包括判断单元，用于：
    获取所述当前信道的信号中多个采样点的频偏偏差；
    对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱；
    基于所述频谱，判断所述信号序列的功率峰值是否位于所述预设符号速率处；
    所述确定单元用于，若所述信号序列的功率峰值位于所述符号速率处，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
  7. 根据权利要求5所述的装置，其特征在于，所述判断单元还用于：
    在获取的每一个所述频偏偏差组成的信号序列中识别得到多个频偏偏差谷值；
    将所述信号序列中不属于所述频偏偏差谷值的频偏偏差设置为零，得到调整后的信号序列；
    所述判断单元对获取的每一个所述频偏偏差组成的信号序列进行快速傅里叶变换，得到所述信号序列的频谱时，具体执行：
    对所述调整后的信号序列进行快速傅里叶变换，得到所述调整后的信号序列的频谱。
  8. 根据权利要求5所述的装置，其特征在于，所述装置还包括检测单元，用于：
    对同步间隔内扫描得到的当前信道的信号进行同步信息检测；
    所述确定单元用于，若在所述同步间隔内所述当前信道的信号包含同步信息，并且在第一时长内计算得到的每一个所述最大频偏包络均值，均在所述频偏要求范围内，确定所述当前信道的信号为有效信号。
  9. 一种电子设备，其特征在于，包括存储器和处理器；
    其中，所述存储器用于存储计算机程序；
    所述处理器用于执行所述计算机程序，具体用于实现如权利要求1至4任意一项所述的信道扫描的方法。
  10. 一种计算机存储介质，其特征在于，用于存储计算机程序，所述计算机程序被执行时，具体用于实现如权利要求1至4任意一项所述的信道扫描的方法。
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US20160205430A1 (en) * 2015-01-08 2016-07-14 Intel Corporation Method and system for fast channel scan for docsis cable modem
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