WO2018161505A1

WO2018161505A1 - Method and device for determining symbol position of primary synchronization signal, and storage medium

Info

Publication number: WO2018161505A1
Application number: PCT/CN2017/098245
Authority: WO
Inventors: 黄舒怀
Original assignee: 深圳市中兴微电子技术有限公司
Priority date: 2017-03-10
Filing date: 2017-08-21
Publication date: 2018-09-13
Also published as: CN108574546A; CN108574546B

Abstract

Disclosed in an embodiment of the present invention is a method for determining a symbol position of a primary synchronization signal, comprising: performing processing on a received radio-frequency signal to obtain a digital baseband signal, and performing sampling on the digital baseband signal to obtain a sampled signal; performing processing on the sampled signal to obtain cumulative power values of the sampled signal over K subframes; determining, according to a preset rule, a first cumulative power value from the cumulative power values of the sampled signal over the K subframes, and determining a subframe position corresponding to the first cumulative power value to be a subframe position of a narrow band primary synchronization signal (NPSS); performing, according to the subframe position of the NPSS, a correlation operation on a pre-configured NPSS and the sampled signal to obtain respective correlation values; and determining, according to the respective correlation values, a symbol position of the NPSS. Also disclosed in the embodiment of the present invention are a device for determining a symbol position of a primary synchronization signal and a computer readable storage medium.

Description

Method, device and storage medium for determining symbol position of main synchronization signal

Cross-reference to related applications

The present application is based on a Chinese patent application filed on Jan. 10, 2017, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present invention relates to the field of Internet of Things, and in particular, to a method, an apparatus, and a computer readable storage medium for determining a symbol position of a primary synchronization signal.

Background technique

The Narrow Band Internet of Things (NB-IoT) technology is an emerging technology in the Internet of Things (IoT). Different from the existing IoT technology, NB-IoT technology is a globally-available Internet of Things technology based on telecom cellular networks; NB-IoT technology license (License) frequency band, can take in-band, guard band or independent carrier Three deployment methods coexist with existing networks, with wide coverage, deep coverage, massive connectivity, low cost, low power consumption, and data security.

As with other cellular communication technologies, the first step in NB-IoT communication is to complete the initial synchronization of the terminal with the system, including time synchronization and frequency synchronization, which can be obtained by the terminal's sweep and master synchronization process. In the related art, the primary synchronization process constructs a primary synchronization signal locally through the terminal, and uses the correlation of the primary synchronization sequence to compare with the received signal (base station transmitted signal) at each time point, and the time point at which the highly correlated signal is located is considered to be According to this idea, NB-IoT can also use its narrowband primary synchronization signal (NPSS, Narrow Band Primary Synchronization Signal) to evaluate the correlation of received signals to obtain primary synchronization, but without any prior information. In this case, this method needs to traverse all possible time points within a radio frame (10ms), whether it is related in the time domain or the frequency domain, this method will eliminate It consumes a lot of hardware resources or digital signal processor (DSP) resources, and continuously receives signals and operations without interruption, and can not reduce power consumption.

NB-IoT has very high requirements on cost and power consumption. According to the simulation data of TR45.820, it is expected that the standby time of the terminal module can be up to 10 years, the single connected module does not exceed 5 US dollars, and in order to reduce the cost, it is possible The use of a low-performance crystal oscillator will result in a larger initial frequency offset (up to 25.5 kHz) between the terminal and the system than in previous cellular communication systems, which has an impact on the initial timing. The primary synchronization method in the technology cannot meet the low cost and low power requirements of NB-IoT.

Summary of the invention

In view of this, embodiments of the present invention are directed to a method, apparatus, and computer readable storage medium for determining a symbol position of a primary synchronization signal.

The technical solution of the embodiment of the present invention is implemented as follows:

In a first aspect, an embodiment of the present invention provides a method for determining a symbol position of a primary synchronization signal, including: processing a received radio frequency signal to obtain a digital baseband signal, and sampling the digital baseband signal to obtain a sampling signal; Processing the sampled signal to obtain a cumulative power value of the sampled signal in K subframes; determining a maximum value of the sampled signal in the cumulative power values of the K subframes as a first cumulative power value, a subframe position corresponding to an accumulated power value is determined as a subframe position of the NPSS; and the pre-configured NPSS is correlated with the sampling signal according to the subframe position of the NPSS to obtain respective correlation values; The correlation value determines the symbol position of the NPSS.

In the above solution, the sampling signal is processed to obtain a cumulative power value of the sampling signal in the K subframes, including: processing the sampling signal according to a preset algorithm, to obtain the sampling signal in one The energy of the K subframes in the radio frame; the energy of the K subframes in the radio frame is accumulated and filtered according to the first preset frame number in a radio frame to obtain the accumulated power value of the sample signal in the K subframes.

In the above solution, the sampling signal is processed according to a preset algorithm to obtain energy of the K subframes of the sampled signal in a radio frame, including: performing conjugate point multiplication on the sampling signal to obtain a a conjugate point multiplication result of the sampled signal; from the sampled signal The K-group conjugate point multiplication result is selected from each of the conjugate point multiplication results, and the K-group conjugate point multiplication result is subjected to an accumulated averaging operation to obtain energy of the K-subframes of the sampled signal in one radio frame.

In the above solution, the maximum value of the sampling signal in the cumulative power values of the K subframes is determined as the first accumulated power value, and the subframe position corresponding to the first accumulated power value is determined as the child of the NPSS. After the frame position, the method further includes: determining, according to the subframe position corresponding to the first accumulated power value, a first frequency offset of the sampling signal; and frequencying the sampling signal according to the first frequency offset Partial compensation.

In the above solution, after frequency offset compensation is performed on the sampling signal according to the first frequency offset, the method further includes: at least two peaks in the accumulated power value of the sampled signal in the K subframes, and And the power difference between the peak value and the maximum value of the sampling signal in the accumulated power values of the K subframes is less than or equal to a first preset threshold value, and the peak value and the sampling signal are in K sub-subjects. When the time difference between the maximum values of the accumulated power values of the frames is greater than or equal to the second preset threshold, and the first frequency offset is greater than the absolute value of the preset operation threshold, the a first peak after the maximum value of the sampled signal in the cumulative power values of the K subframes is determined as the first cumulative power value; and at least two peaks are present in the cumulative power value of the sampled signals in the K subframes, And the power difference between the peak value and the maximum value of the sampling signal in the accumulated power values of the K subframes is less than or equal to the first preset threshold value, and the peak value and the sampling signal are at the K The maximum of the cumulative power values of the sub-frames When the time difference between the time difference is greater than or equal to the second preset threshold value, and the first frequency offset is less than the inverse of the absolute value of the preset operation threshold, the sampling signal is in K sub-subjects Determining, as the first accumulated power value, a first peak value before a maximum value of the accumulated power values of the frame, and returning to performing performing the subframe position corresponding to the first accumulated power value as a subframe of the NPSS The steps of the location.

In the above solution, the correlation between the pre-configured NPSS and the sampling signal is performed according to the subframe position of the NPSS, to obtain each correlation value, including: obtaining a frequency offset value of the preset number of segments; Performing a frequency offset compensation process on the sampled signal to obtain a processed sample signal of the preset number of segments; and The constructed NPSS is correlated with the processed sampled signals of the preset number of segments to obtain the correlation values.

In the above solution, determining the symbol position of the NPSS according to the correlation values includes: accumulating and filtering the correlation values according to the second preset frame number to obtain power values corresponding to the correlation values; And selecting a preset number of peaks from the power values corresponding to the correlation values; and calculating, in the power values corresponding to the correlation values, an average value of power values other than the preset number of peak values; Determining, by the power value corresponding to each correlation value, a power value greater than a product of the average value and a preset decision threshold, and determining a symbol position in a subframe corresponding to a maximum value of the selected power values as the NPSS Symbol location.

In a second aspect, an embodiment of the present invention provides a device for determining a symbol position of a primary synchronization signal, including: a sampling module configured to process a received radio frequency signal to obtain a digital baseband signal, and sample the digital baseband signal a sampling signal, configured to process the sampled signal to obtain an accumulated power value of the sampled signal in K subframes; and a first determining module configured to accumulate power of the sampled signal in K subframes The maximum value of the value is determined as a first cumulative power value, and the subframe position corresponding to the first accumulated power value is determined as a subframe position of the NPSS; and the operation module is configured to be pre-framed according to the subframe position of the NPSS The constructed NPSS performs a correlation operation with the sampling signal to obtain each correlation value, and the second determining module is configured to determine a symbol position of the NPSS according to the correlation values.

In the above solution, the processing module includes: a processing submodule configured to process the sampling signal according to a preset algorithm to obtain energy of the K subframes of the sampling signal in a radio frame; and an accumulation filtering submodule, The energy of the K subframes in the radio frame is accumulated and filtered according to the first preset frame number, and the accumulated power value of the sample signal in the K subframes is obtained.

In the above solution, the processing submodule is configured to perform a conjugate point multiplication operation on the sampling signal to obtain a conjugate point multiplication result of the sampling signal; and multiply each conjugate point of the sampling signal In the result, the K-group conjugate point multiplication operation result is selected, and the K-group conjugate point multiplication operation result is separately subjected to an averaging operation to obtain the energy of the K-subframes of the sampled signal in one radio frame.

In the above solution, the apparatus further includes: a compensation module configured to determine a maximum value of the accumulated power values of the sampling signals in the K subframes as a first accumulated power value, and corresponding to the first accumulated power value After the subframe position is determined as the subframe position of the NPSS, according to the Determining a first frequency offset of the sampling signal according to a subframe position corresponding to the accumulated power value; performing frequency offset compensation on the sampling signal according to the first frequency offset.

In the above solution, the device further includes: an adjusting module, configured to perform frequency offset compensation on the sampling signal according to the first frequency offset, and at least two of the accumulated power values of the sampling signal in the K subframes a peak value, and the power difference between the peak value and the maximum value of the sampling signal in the cumulative power values of the K subframes is less than or equal to a first preset threshold value, and the peak value and the sampling value And when the time difference between the maximum values of the accumulated power values of the K subframes is greater than or equal to the second preset threshold, and the first frequency offset is greater than the absolute value of the preset operation threshold Determining, by the first peak after the maximum value of the accumulated power values of the K subframes, the first accumulated power value; wherein the sampling signal is present in at least the accumulated power values of the K subframes Two peaks, and the power difference between the peak value and the maximum value of the sampling signal in the cumulative power values of the K subframes is less than or equal to the first preset threshold value, and the peak value is Cumulative work of sampled signals in K subframes When the time difference between the maximum values in the rate values is greater than or equal to the second predetermined threshold value, and the first frequency offset is less than the inverse of the absolute value of the preset operation threshold, Determining, by the first peak, the first peak before the maximum value of the accumulated power values of the K subframes is the first accumulated power value, triggering the first determining module to return to perform execution of the first cumulative power value The subframe position is determined as the subframe position of the NPSS.

In the above solution, the operation module is configured to obtain a frequency offset value of the preset number of segments; and perform frequency offset compensation processing on the sampling signal according to the frequency offset value of the preset number of segments, to obtain the pre-prepared a segmented number of processed sampled signals; performing a correlation operation between the pre-configured NPSS and the preset number of segments of the processed sample signals according to the subframe position of the NPSS, to obtain the Relevant values.

In the above solution, the second determining module is configured to accumulate and filter the correlation values according to the second preset frame number to obtain power values corresponding to the correlation values, and corresponding to the correlation values. A preset number of peaks is selected from the power values; and an average value of power values other than the preset number of peaks is calculated among the power values corresponding to the correlation values; and power values corresponding to the correlation values And selecting a power value that is greater than a product of the average value and a preset decision threshold, and determining a symbol position in the subframe corresponding to the maximum value of the selected power values as the NPSS Symbol location.

In a third aspect, an embodiment of the present invention further provides a computer readable storage medium having stored thereon a computer program, the computer program being executed by a processor to implement the steps of any of the foregoing methods.

The method and device for determining the symbol position of the primary synchronization signal and the computer readable storage medium provided by the embodiment of the present invention firstly process the received radio frequency signal to obtain a digital baseband signal, and sample the digital baseband signal to obtain a sampling signal. Then, the sampled signal is processed to obtain a cumulative power value of the sampled signal in K subframes, and the maximum value of the sampled signal in the accumulated power values of the K subframes is determined as a first accumulated power value, and the first accumulated power value is corresponding. The subframe position is determined as the subframe position of the NPSS, so that the approximate position of the time point of the NPSS to be synchronized can be known. Finally, according to the subframe position of the NPSS, the pre-configured NPSS is correlated with the sampling signal to obtain a correlation. For each correlation value, the symbol position of the NPSS is determined according to each correlation value; that is, the embodiment of the present invention processes the sampled signal to obtain the cumulative power value of the sampled signal in K subframes, and accumulates in the K subframes according to the sampled signal. The power value can determine the subframe position of the corresponding NPSS, so that the NPSS and the non-NPSS are avoided. The sampling signal performs correlation operations and avoids continuous reception of signals, thus reducing the amount of computation for performing correlation operations, thereby reducing the cost and power consumption of the NB-IoT for the main synchronization process, and finally, improving the NB-IoT master. The efficiency of synchronization. That is to say, the solution of the embodiment of the present invention can meet the requirements of low cost and low power consumption of the NB-IoT, and improve the efficiency of the primary synchronization in the NB-IoT.

DRAWINGS

1 is a schematic flow chart of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention;

2 is an optional schematic flowchart of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention;

3 is another optional schematic flowchart of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention;

4 is still another optional flow diagram of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention;

FIG. 5 is an optional schematic flowchart of S402 corresponding to FIG. 4 according to an embodiment of the present disclosure;

FIG. 6 is an optional schematic flowchart of S403 corresponding to FIG. 4 according to an embodiment of the present disclosure;

FIG. 7 is an optional schematic flowchart of S404 corresponding to FIG. 4 according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of an example of an apparatus for performing NB-IoT primary synchronization according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic structural diagram of an NPSS subframe boundary operation unit in FIG. 8 according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of an NPSS symbol boundary operation unit in FIG. 8 according to an embodiment of the present invention; FIG.

11 is a timing diagram of a time domain matched filter according to an embodiment of the present invention;

FIG. 12 is a timing diagram of performing NB-IoT main synchronization according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of an apparatus for determining a symbol position of a main synchronization signal according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings.

An embodiment of the present invention provides a method for determining a symbol position of a primary synchronization signal. FIG. 1 is a schematic flowchart of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention; as shown in FIG. 1, the method includes:

S101: processing the received radio frequency signal to obtain a digital baseband signal, and sampling the digital baseband signal to obtain a sampling signal;

In order to realize the initial synchronization process between the terminal and the system, first, the terminal receives the radio frequency signal sent by the incoming system, and the terminal performs front end processing on the radio frequency signal to obtain a digital baseband signal, and then samples the digital baseband signal.

Here, the sampling of the digital baseband signal may be sequential sampling in accordance with the standard sampling rate, or downsampling the digital baseband signal, and the sampling frequency of the down sampling may be according to performance requirements and cost in the design target. / power consumption requirements to determine, for example, the sampling frequency can be an integer multiple of 240KHz, multiples can be selected 1, 2, 4, 8; here, need to be explained The embodiment of the present invention does not specifically limit the sampling mode and the sampling frequency.

S102: Processing the sampled signal to obtain a cumulative power value of the sampled signal in K subframes;

Here, the sampled signals obtained by the terminal sampling are all encapsulated into a radio frame, and each of the subframes in the radio frame is encapsulated with a plurality of sampling signals, in order to obtain the accumulated power value of the sampled signals in the K subframes, in an optional In an embodiment, FIG. 2 is an optional schematic flowchart of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention. As shown in FIG. 2, S102 may include:

S102A: processing the sampled signal according to a preset algorithm to obtain energy of the K subframes of the sampled signal in a radio frame;

In order to obtain the energy of the K subframes of the sampled signal in a radio frame, in an optional embodiment, S102A may include:

Performing a conjugate point multiplication operation on the sampled signal to obtain a conjugate point multiplication result of the sampled signal; selecting K sets of conjugate point multiplication results from the conjugate point multiplication results of the sampled signals, respectively conjugated to the K set The result of the point multiplication operation is subjected to an accumulated averaging operation to obtain the energy of the K sub-frames of the sampled signal in one radio frame.

Specifically, by performing a conjugate point multiplication operation between the matrices formed by the sampled signals in adjacent symbols in the radio frame, the conjugate point multiplication result of the sampled signal can be obtained, and then multiplied from each conjugate point of the sampled signal. In the operation result, the K group conjugate point multiplication result is selected according to the preset number. For example, 10 conjugate point multiplication results are selected in each group, and after the K group conjugate point multiplication result is obtained, each group is conjugated. The result of the point multiplication operation is subjected to an accumulated averaging operation to obtain the energy of the K sub-frames of the sampled signal in one radio frame.

S102B: Accumulating and filtering the energy of the K subframes of the sampled signal in a radio frame according to the first preset number of frames to obtain the accumulated power value of the sampled signal in the K subframes.

In order to convert the energy of the K-subframes of the sampled signal into a power value in a radio frame, the power value is used to represent the energy, specifically, the energy of the K-subframes of the sampled signal in one radio frame is subjected to the first preset frame. The accumulation of the number and the smoothing of the filter can obtain the cumulative power value of the sampled signal in K subframes.

For example, the above K may be an integer greater than or equal to 70 and less than or equal to 140.

The first preset frame number can be flexibly set to adapt to the NB-IoT scene change. Demand.

S103: determining, as a first accumulated power value, a maximum value of the accumulated power values of the sampled signals in the K subframes, and determining a subframe position corresponding to the first accumulated power value as a subframe position of the NPSS;

Specifically, since the terminal and the system perform frequency synchronization in addition to time synchronization in the initial synchronization process, frequency offset is caused in the process of frequency synchronization, and in an optional embodiment, in order to eliminate the frequency offset, FIG. 3 is a schematic diagram of another optional process for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention. As shown in FIG. 3, after the step S103, the method may further include:

S103A: Determine, according to a subframe position corresponding to the first accumulated power value, a first frequency offset of the sampling signal;

S103B: Perform frequency offset compensation on the sampling signal according to the first frequency offset.

After determining the subframe position corresponding to the first accumulated power value in S103, the subframe position of the NPSS is known, and then the point multiplication between adjacent symbols near the NPSS subframe position can be selected according to the subframe position of the NPSS. As a result of the yoke operation, the first frequency offset is calculated according to the result of the point multiplication conjugate operation between adjacent symbols near the NPSS subframe position, and the frequency offset compensation is performed on the sampling signal according to the first frequency offset. Here, the method of frequency offset compensation may employ a piecewise quantized phase angle value algorithm or a coordinate rotation digital calculation (CORDIC) algorithm. This embodiment of the present invention does not specifically limit this.

In order to determine a more accurate subframe position of the NPSS, in an optional embodiment, S103B may further include:

There are at least two peaks in the accumulated power value of the sampled signal in the K subframes, and the power difference between the peak value and the maximum value of the sampled signal in the accumulated power values of the K subframes is less than or equal to the first preset threshold. And the time difference between the peak value and the maximum value of the sampled signal in the accumulated power values of the K subframes is greater than or equal to the second preset threshold value, and the first frequency offset is greater than a preset operation threshold. In the absolute value, the first peak after the maximum value of the accumulated power values of the K subframes is determined as the first cumulative power value, and at least two peaks exist in the accumulated power values of the sampled signals in the K subframes. And the power difference between the peak value and the sampling signal in the cumulative power value of the K subframes is less than or equal to the first preset threshold value, and the peak value and the sampling signal are in the cumulative power value of the K subframes The time difference between the maximum values is greater than or equal to the second pre- When the threshold is set, and the first frequency offset is less than the inverse of the absolute value of the preset operation threshold, the first peak before the maximum value of the accumulated power values of the K subframes is determined as the first An accumulated power value is returned to perform the step of determining the subframe position corresponding to the first accumulated power value as the subframe position of the NPSS.

The first preset threshold value and the second preset threshold value are all preset values.

The first accumulated power value can be re-determined by the above method, and the subframe position of the NPSS is re-determined according to the re-determined first accumulated power value, so that the accuracy of determining the subframe position of the NPSS can be improved.

S104: Perform correlation operation between the pre-configured NPSS and the sampling signal according to the subframe position of the NPSS, to obtain each correlation value;

Here, the pre-configured NPSS is constructed according to the requirements of the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project) 36.211 protocol standard;

Specifically, a fixed-size small window is opened on the sampling signal centered on the NPSS subframe position, and if the small window includes M sampling time points, the sampling signal in the small window and the narrow-band main synchronization signal are Performing the time domain sliding correlation operation, M correlation values can be obtained, where M is an integer greater than or equal to 2; in the embodiment of the present invention, the time domain sliding correlation operation can be completed by using a matched filter.

In addition, it should be noted that the sampling signal for performing the correlation operation on the primary synchronization signal may be after the first frequency offset compensation, or may be after the first frequency offset compensation, where the embodiment of the present invention does not Specifically limited.

In order to eliminate the influence of the frequency offset on the correlation value, in an optional embodiment, S104 may include:

Obtaining a frequency offset value of the preset number of segments; respectively performing frequency offset compensation processing on the sampled signal according to the frequency offset value of the preset number of segments, to obtain a processed sample signal of a preset number of segments; and determining a subframe position according to the NPSS The pre-configured NPSS is correlated with the processed sampled signals of the preset number of segments to obtain respective correlation values.

The method for obtaining the frequency offset value of the preset number of segments may be: segmenting the maximum initial frequency offset value to obtain a frequency offset value of the preset number of segments; wherein the maximum initial frequency offset value is initial The maximum initial frequency offset value generated during the frequency synchronization process during the initial synchronization process; and the preset number of segments can be flexibly set to meet the changing requirements of the NB-IoT scenario.

Specifically, in the "subframe synchronization" process, that is, the NPSS subframe position determined in S103 is centered on a fixed-size small window, and it is assumed that the small window includes M time points, and the window will pass through The processed sampled signal of the preset number of segments and the local narrowband primary synchronization signal are subjected to a time domain sliding correlation operation, and each correlation value is obtained, wherein the number of each correlation value is a preset number of segments multiplied by M.

For example, when M=5 and the number of preset segments is 10, 50 sampling signals are obtained after segmentation frequency offset processing for each sampled signal, and 50 sampling signals are correlated with NPSS to obtain a correlation operation. With 50 correlation values, the accuracy of the determined symbol position of the NPSS can be improved by the above method.

In addition, the frequency offset value according to the preset number of segments is respectively subjected to frequency offset compensation processing on the sampled signal, and the processed sampled signal obtained by obtaining the preset number of segments may be: using a serial working mechanism for the same segment of the sampled signal. Offset compensation; it is also possible to use the parallel working mechanism for frequency offset compensation for the same segment of the sampled signal; it can also use the serial working mechanism for frequency offset compensation for different segments of the sampled signal, or parallel working mechanism for different segments of the sampled signal Perform frequency offset compensation. Among them, the frequency offset compensation by using the serial working mechanism for the same sampling signal can reduce the cost and power consumption of the NB-IoT main synchronization.

The maximum initial frequency offset value includes the first frequency offset plus the second frequency offset.

S105: Determine a symbol position of the NPSS according to each correlation value.

Here, in determining the symbol position of the NPSS according to each correlation value, at least the following two methods may be used:

The first manner may determine, according to the size of each correlation value, a symbol position in a subframe corresponding to a maximum value among the correlation values as a symbol position of the NPSS;

The second method can determine the symbol position of the NPSS according to the following method. In a specific implementation process, S105 can include:

Accumulating and filtering each correlation value according to the second preset frame number to obtain a power value corresponding to each correlation value; selecting a preset number of peak values from the power values corresponding to the correlation values; In the power value corresponding to the value, an average value of the power values other than the preset number of peaks is calculated; and among the power values corresponding to the correlation values, a power value greater than the product of the average value and the preset decision threshold is selected, and the selected The symbol position in the subframe corresponding to the maximum value among the power values is determined as the symbol position of the NPSS.

The second preset frame number can be flexibly set to meet the changing needs of the NB-IoT scenario.

Here, it should be noted that each correlation value needs to be converted into a power value. Specifically, the correlation values are respectively accumulated and filtered and smoothed according to the second preset frame number, so that each correlation value can be converted into a power value; and among the power values corresponding to the correlation values, the preset number is calculated. The average value of the power values other than the peak value; in the power value corresponding to each correlation value, the power value greater than the product of the average value and the preset decision threshold is selected, and the frequency offset corresponding to the maximum value of the selected power values is determined as the synchronization. The frequency offset value in the process may then calculate a second frequency offset value according to the difference between the frequency offset value and the first frequency offset value, and the second frequency offset value may be used in subsequent processing.

In order to further embodies the object of the present invention, one or more embodiments of the method for determining the symbol position of the above-described primary synchronization signal will be described below by way of example.

First, according to the application scenario, the sampling frequency of the down sampling is selected to be 240 KHz, the subframe synchronization processing time at the determination of the subframe boundary (position) is the number of radio frames N ₁ , and the symbol synchronization processing time at the determination of the symbol boundary (position) is wireless. The number of frames N ₂ , the number of segments of the frequency offset is N ₃ , the operation threshold Δf _Th , and the maximum initial frequency offset Δf ₀ .

FIG. 4 is still another optional flow diagram of a method for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention. As shown in FIG. 4, the method includes:

S401: The base station sends a radio frequency signal to the terminal, and the terminal performs front end processing on the received radio frequency signal to obtain a digital baseband signal, and downsamples the digital baseband signal according to the selected sampling frequency of 240 KHz, thereby obtaining time domain data at a rate of 240 KHz;

S402: Using time-domain data obtained by downsampling, using a sequence feature of the NPSS in the subframe, calculating and evaluating a time domain cumulative power of the time domain data in each subframe, obtaining a subframe position of the NPSS, as Primary synchronization (subframe synchronization) result, this step requires multi-frame joint evaluation, the number of repeated radio frames is configurable "subframe synchronization processing time" N ₁ ;

S403: In the subframe position of the NPSS obtained in S402, using the feature of the NPSS sequence, the first frequency offset is estimated by the adjacent symbol conjugate multiplication phase shift method, and the step also needs to perform multi-frame joint evaluation, and the number of repeated radio frames After the configurable "subframe synchronization processing time" N ₁ , S403 and S402 processing time reaches the specified number of radio frames, proceeds to S404, otherwise continues to repeat S402 to S403;

S404: Perform frequency offset compensation on the time domain data in the subframe position of the NPSS obtained in S402, and then perform time domain correlation calculation with the local NPSS signal, and locate the symbol position of the NPSS by evaluating the relevant power peak method, and simultaneously segment by The frequency offset compensation comparison method estimates the residual position offset value of the symbol position of the NPSS.

This step also requires multiple radio frame joint evaluation decisions. The number of repeated radio frames is a configurable "symbol synchronization processing time" N ₂ ; for the processing of an "NPSS sub-frame position" data, if the specified radio frame is not reached The number continues the multi-frame accumulation processing of the current NPSS subframe position. Otherwise, the next "NPSS subframe position" is selected for processing until all the "NPSS subframe positions" given in S402 have been processed by S404. At this time, S404 will make a decision. If the results obtained by S402 and S404 are considered valid, the "symbol position of NPSS" and "total initial frequency offset" are output as the final result of the main synchronization process, otherwise return to S402 and repeat S402 to S404.

FIG. 5 is an optional schematic flowchart of S402 corresponding to FIG. 4 according to the embodiment of the present invention. As shown in FIG. 5, taking K=140 as an example, S402 may include:

S402A: For the downsampled signal r, starting from an arbitrary time starting point, a continuous 150 symbols are selected, and a conjugate point multiplication operation is performed between each adjacent symbol:

Among them, the above

For the conjugate of the sampled signal in the jth symbol,

The conjugate transpose of the sampled signal in the j+1th symbol.

S402B: The result of the point multiplication of S402A is cumulatively averaged every 10, and 140 accumulated average values are calculated by a recursive method as shown in the following formula:

Where S _k represents an accumulated average value, and the 140 accumulated average values obtained above correspond to 140 candidate subframe time points in one radio frame.

S402C: Convert the accumulated average value obtained by S402B into a power value according to the following formula to represent the energy size, and perform n (n=N ₁ ) frame accumulation and filter smoothing:

E _n =αE _n-1 +(1-α)|S| (4)

Where S is the accumulated average value S _k obtained by the above formulas (2) and (3), and |S| represents energy. In the above formula (4), when n=1, E ₁ = (1-α) |S|; when n=N ₁ ,

Where E _n is the multi-frame accumulation result, α is the set filter factor; Re(S) is the real part of S, and Im(S) is the imaginary part of S.

Here, in order to mitigate the effects of drift time, S402C using an infinite impulse response (IIR, Infinite Impulse Response) filter for weighting at the N ₁ radio frames accumulated.

S402D: Determine the subframe position of the NPSS according to the decision rule 1, specifically, search for the power value obtained in S402C, and directly select the time position corresponding to the maximum value as the subframe position of the NPSS.

Among them, the judgment rule one can be expressed by the following formula:

Wherein, the above |E _n,k | represents the sum of the accumulated results of the N ₁ radio frames corresponding to each symbol.

At this point, the subframe position of the NPSS is obtained.

Here, it should be noted that when K is less than 140 and greater than or equal to 70, the subframe position of the NPSS determined in S402 has a missed detection position, so it is necessary to repeatedly execute S402 to prevent missed detection.

FIG. 6 is an optional schematic flowchart of S403 corresponding to FIG. 4 in the embodiment of the present invention. As shown in FIG. 6, S403 may include:

S403A: Acquire the result of S402B.

S403B: The results of the N ₁ S402B radio frame accumulation;

S403C: According to the result of the subframe position of the NPSS given by S402D, a result representing the conjugate multiplication of the adjacent symbols of the NPSS is selected in S402A, and the angle is obtained and converted into a frequency offset value as follows:

Where T _s is the NPSS symbol period, and P _{θ, j} represents the P value corresponding to the subframe j near θ,

Indicates that the conjugate of the P value corresponding to the subframe j+1 near θ is taken,

It is the time position corresponding to the maximum value in S402D.

Here, after S403C, the method may further include:

Performing a peak search in the power value obtained by S402C, and then selecting a specified number of peaks according to decision rule two, and selecting one one in this embodiment, and corresponding time points thereof

As a subframe position for the NPSS, where the decision rule 2 includes:

If there are at least two peaks, and the power difference between the peak value and the maximum value is less than or equal to the first preset threshold value, and the time difference between the peak value and the maximum value is greater than or equal to the second preset threshold value, When Δf ₁ >|Δf _Th |, the peak value after the maximum value (to the right of the time axis) is selected, and when Δf ₁ <−|Δf _Th |, the peak value before the maximum value (to the left of the time axis) is selected.

In the embodiment of the apparatus of the present invention, the result of S403C and the result of S402D have a sequential relationship in time series, and the apparatus of the present invention may also adopt a delay of several clock cycles in timing in the timing of the decision rule two.

FIG. 7 is an optional schematic flowchart of S404 corresponding to FIG. 4 in the embodiment of the present invention. As shown in FIG. 7, S404 may include:

S404A: Perform frequency offset compensation of Δf ₁ on the time domain data according to the result obtained by S403C, and use a piecewise quantized phase angle value algorithm or a CORDIC algorithm for the compensation operation.

S404B: Local time domain NPSS signals are generated according to equations (8) and (9):

S _l ={1,1,1,1,-1,-1,1,1,1,-1,1} l=3,4,...,13 (9)

Wherein, the value of N is a multiple of the sampling frequency multiplied by 16; according to the subframe position of the NPSS obtained by S402D, the current position of the first NPSS symbol

A small window of size T _resync (sampling point) is opened for the center, and the time domain sliding correlation operation is performed with the local NPSS signal and the frequency offset compensated time domain data in this window. In this example, a matched filter is used. The sliding correlation operation is completed, and the matching filtering algorithm is as follows:

Where r _m represents the data obtained after segmentation frequency offset compensation for the time domain data, T _resync is the set value, and d _{m is the} time domain NPSS sequence, and the operation is the above formula (8), and the root is 5 The ZC sequence is obtained by IFFT transform and adding CP. T is the number of sampling points of 11 consecutive NPSS symbols, f _s is the sampling frequency, Δf=Δf ₁ +Δf ₂ , which is the first frequency offset value and the second frequency offset value. And n is the sampling point count of the resynchronization window, and the window size can be flexibly configured, and is determined by the signal to noise ratio of the application scenario and the initial frequency offset. In combination with the device proposed by the present invention, the example uses a window of 3 symbols. .

S404C: Convert the correlation result obtained by S404B into a power value to represent the energy size, and perform multi-frame accumulation and filter smoothing. The specific operation is consistent with S402C, and the accumulated number of radio frames is N ₂ .

S404d: applying a segment offset hypothesis results of S404A, S404B and S404C will be repeated several times, i.e. the number of segments preset number of repetitions is N _3, based on the choice of the frequency offset of the formula:

Wherein, the above N ₃ is an odd number; Δf _{0 is} equivalent to the maximum initial frequency offset value, and the maximum initial frequency offset value is segmented by using the above formula (11) and formula (12) to obtain a frequency offset value of the preset number of segments. Δf(n).

S404E: Search for N _p peaks (including the maximum value) among all the power values obtained in S404C and S404D, and average the power values after the peaks are removed, and then obtain a resynchronization result according to the preset rule.

(ie, the symbol position of the NPSS) and the frequency offset estimation result Δf.

The above preset rules are as shown in the above formula (13), where E _k represents all the power values obtained by S404C and S404D, k=1, 2..., N _p , where N _p is the set value, |E _m | is the correlation power value of each sampling point and frequency offset after the culling peak obtained by S404C and S404D, and TH _E is a preset decision threshold,

It is the average.

FIG. 8 is a schematic diagram of an apparatus for performing NB-IoT primary synchronization according to an embodiment of the present invention. As shown in FIG. 8, the apparatus for performing NB-IoT primary synchronization includes a processor and an interface unit 81, and a data pre-processing unit 82. Control unit 83, first frequency offset estimation unit 84, NPSS subframe boundary operation unit 85, decision unit 86, NPSS symbol boundary operation unit 87, and storage unit 88; among them, processor and interface unit 81, data pre-processing unit 82, and The storage unit 88 belongs to a common resource of the NB-IoT terminal. In the example of the present invention, the processor and the interface unit 81 are responsible for running the scheduling software of the main synchronization process, including configuring operating parameters of other units, driving other units to run, and collecting operation results; The pre-processing unit 82 is responsible for processing the data received by the NB-IoT terminal from the antenna for processing by the main synchronization process, including mixing, filtering, Low Noise Amplifier (LNA), and variable gain amplifier ( VGA, Variable Gain Amplifier), Analog-to-Digital Converter (ADC), Digital Front End (DFE, Digital Front End), etc. The radio frequency data is converted into baseband data suitable for digital signal processing. The example of the present invention also adds an important downsampling function to the general hardware unit, and reduces the computational amount and occupation of the main synchronization processing flow by reducing the rate of the data source. Resources, otherwise if you try a large number of frequency offset possible values and all symbol position possible values directly in the 19200 sampling points, a huge amount of computation is required. The example of the present invention uses a sampling rate of 240 kHz, and the computational amount can be reduced to 1 by downsampling. /8, and reduce the hardware size, especially the resource consumption of the storage unit 88; the storage unit 88 is responsible for buffering the input process data and the operation data and results of other units, or Other processes of the NB-IoT terminal are reused to reduce terminal costs.

The other units are unique units implemented by the NB-IoT terminal primary synchronization processing apparatus in the present invention, and include a control unit 83, a first frequency offset estimation unit 84, an NPSS subframe boundary operation unit 85, an NPSS symbol boundary operation unit 87, and a decision. Unit 86; The function of control unit 83 is to control the operational timing of other units and to control the interface of storage unit 88.

FIG. 9 is a schematic structural diagram of an NPSS subframe boundary operation unit in FIG. 8 according to an embodiment of the present invention. As shown in FIG. 9, the NPSS subframe boundary operation unit 85 is multiplied by a shift register 921 and a conjugate point. The operator 922, the complex accumulating averager 923, the register set 924, the register 925, and the recursive operator 926 are configured; wherein the shift register 921 is configured to buffer input data of one symbol, and the input data is shifted and outputted to implement adjacent The sampling point data of the two symbols is aligned; the conjugate point multiplier 922 performs the real-time operation of the adjacent two symbol data according to the above formula (1) to obtain the result of the conjugate point multiplication; the complex accumulating averager 923 and the register 925 together The conjugate point multiplication result of the 922 output is subjected to every 10 accumulated averaging; the register set 924 is configured to buffer the conjugate point multiplication result of the current sub-frame; the recursive operator 926 performs real-time according to the above formulas (2) and (3). The recursive operation outputs 140 results every 10 ms, corresponding to the starting positions of 140 candidates of the subframe in which the NPSS is located; the power estimator 951 converts the output of the recursive operator 926 into power according to the above formula (5). Characterization Correlation between symbols; the floating point accumulator 952 completes the accumulation of the above formula (4), and stores the result in the first working RAM 901. After the corresponding time of the next radio frame arrives, the last result is read from the RAM. To accumulate the current power value, in order to mitigate the influence of time drift, the IIR filtering method is used for accumulating. In order to improve performance, a large amount of radio frame data may be used for accumulating. When the number of accumulated frames is large, floating point format is required. The operation is performed; the online comparator 954 compares the accumulated results in real time when the last frame is accumulated, and the maximum value is output to the decision module 955, which saves the time for storing the data in the RAM and then reading out; the peak searcher 953 is used to search for the other peaks except the maximum value in the first working RAM 901, and output to the decision module 955; the decision module 955 determines whether the maximum value and the peak value output by the peak searcher 953 and the online comparator 954 are determined according to a predetermined rule. Valid, the time point corresponding to the selection of the appropriate value is the subframe position of the NPSS (corresponding to the subframe position of the NPSS described above) as the output result of step S402, The embodiment directly outputs the time point corresponding to the maximum value as the subframe position of the NPSS; the first frequency offset estimation unit is composed of the complex accumulation averager 931 and the frequency offset calculator 932, and further requires the second in the storage unit 88. Work RAM 902 to assist in the completion of the work. The multi-accumulation averager 923 accumulates the 140 results output by the recursive operator 926 across the frame, and the accumulated result is temporarily stored in the second working RAM 902. After the decision module 955 obtains the subframe position of the NPSS, the position value corresponds to The address is selected from one of the 140 data in the second working RAM 902, and is output to the frequency offset calculator 932. The frequency offset calculator 932 performs the angle-of-angle and frequency offset conversion work in the above formula (7) to obtain the first frequency. Deviation Δf ₁ .

FIG. 10 is a schematic structural diagram of an NPSS symbol boundary operation unit in FIG. 8 according to an embodiment of the present invention. As shown in FIG. 10, the NPSS symbol boundary operation unit 87 is composed of a data selector 1041 and a local NPSS signal generator 1042. The frequency offset compensator 1043 and the time domain matched filter 1044 are combined. In addition, the storage unit 88 is required to cooperate. The control unit 83 provides the subframe position information of the NPSS according to S402, and stores the data of the subframe where the NPSS is located in the storage unit 88. In the second working RAM 902, the size of the resynchronization window only needs to buffer data of one subframe within one subframe, and more than one subframe needs to buffer data in the entire window, and the device in this embodiment has the most The data of 2 subframes is buffered; the data selector 1041 is responsible for selecting the current real-time data or the data read from the second working RAM 902. The selection rule is that when the subframe where the NPSS of each radio frame arrives, the real-time input data is selected, and the other The time selects the data read from the second working RAM 902; the frequency offset compensator 1043 performs frequency offset compensation on the data output by the data selector, since the device uses serializer Mode, the maximum deviation of the number N of the segment 9, when a 25.5KHz application scenario in the maximum absolute value of the initial frequency offset Δf is _0, when the above equation (11), the segment offset is set {25.5KHz , 19.1KHz, 12.8KHz, 6.4KHz, 0, -6.4KHz, -12.8KHz, -19.1KHz, -25.5KHz}, the frequency offset estimation error can be controlled within 3.2KHz; if the above formula (12) is used, the frequency The partial estimation error can be further controlled within 1.4 kHz; the specific implementation of the segmentation frequency offset compensation operation can adopt the CORDIC algorithm or the piecewise quantization phase compensation method; the local NPSS signal generator locally generates the time domain NPSS according to the above formula (8). The signal is generated in real time by generating the frequency domain root sequence in real time, and then adding 0 to the integer power of 2 to do the inverse discrete Fourier transform (IFFT) to the time domain plus CP generation.

11 is a timing diagram of a time domain matched filter according to an embodiment of the present invention. As shown in FIG. 11, the time domain matched filter completes the received signal output by the frequency offset compensator 1043 and the local signal output by the local NPSS signal generator 1042. correlation operation between its basic structure as illustrated, r 'is the received signal preprocessing, d ₀ -d _n NPSS local sequence signal, characterized by using NPSS sequences in the subframe 11 when the unit is implemented, the The 11 consecutive symbols are treated as the same NPSS symbol, so one basic filter hardware can be reused to reduce resource consumption. In addition, the symmetry of the NPSS root sequence itself can be utilized to further reduce the local NPSS signal generator 1042. The hardware size of the domain matched filter 1044.

Similarly, in order to save resources and reduce costs, the subsequent processing of the output result of the NPSS symbol boundary operation unit 87 multiplexes the decision unit 86 used by the aforementioned NPSS subframe boundary operation unit 85. The output of time domain matched filter 1044 is converted to power estimator 951, converted to a power value, and then accumulated by floating point accumulator 952, which accumulates the obtained power value, and is input to online comparator 954 to find the maximum value. On the other hand, it is temporarily stored in the first working RAM 901, and then several peaks are found by the peak searcher (two in this embodiment), and finally the decision unit 86 determines the NPSS symbol position and the second according to a predetermined rule. The frequency offset estimate is output as the final result of the primary synchronization process.

In this example, the peak searcher will get two peaks, and the decision module 955 will first reject the maximum value and the two peaks, then accumulate all remaining power values, representing the noise power level, and then find the maximum value. And the ratio of the peak value to the average value, if the ratio is greater than the preset threshold, it is judged to be valid, and the maximum value is selected, and the corresponding sampling point time position is the symbol position of the NPSS, and the corresponding frequency offset is The total initial frequency offset.

FIG. 12 is a timing diagram of performing NB-IoT primary synchronization according to an embodiment of the present invention. The apparatus of the embodiment of the present invention can process up to 10 segment frequency offsets. When using the decision rule of the above formula (12), the initial The error of the frequency offset estimation is controlled within 1.4 kHz, which effectively copes with the scene with large initial frequency offset; the serial working mechanism is adopted when processing multiple segment frequency offsets, and the control unit 83 increases the received radio frequency signal according to the working timing. Control, in particular, the control unit 83 controls the radio frequency switch in the data pre-processing unit 82 to turn on the radio frequency switch in the data pre-processing unit 82 to receive the radio frequency signal only when the sub-frame position of the NPSS arrives, in the NPSS sub- At the end of the frame position, the RF switch in the data pre-processing unit 82 is turned off to stop receiving the RF signal, and the RF signal can be shortened to 1/10 by controlling the RF switch, that is, the serial working mechanism and the RF are used. The control of the switch can significantly reduce the power consumption of the NB-IoT terminal in the main synchronization process.

The method for determining the symbol position of the primary synchronization signal provided by the embodiment of the present invention firstly processes the received radio frequency signal to obtain a digital baseband signal, and samples the digital baseband signal. Obtaining a sampling signal, and then processing the sampling signal to obtain a cumulative power value of the sampling signal in K subframes, and determining a first cumulative power value from the accumulated power values of the sampling signals in the K subframes according to a preset rule, which will be first The subframe position corresponding to the accumulated power value is determined as the subframe position of the NPSS, so that the approximate position of the time point of the NPSS to be synchronized can be known, and finally, the pre-configured NPSS and the sampling signal are constructed according to the subframe position of the NPSS. Performing a correlation operation to obtain each correlation value, and determining a symbol position of the NPSS according to each correlation value; that is, the embodiment of the present invention processes the sampled signal to obtain a cumulative power value of the sampled signal in K subframes, according to the sampling signal. The accumulated power values of the K subframes can determine the subframe position of the corresponding NPSS, so that the correlation between the NPSS and the sampling signals of the subframe in which the non-NPSS is located is avoided, and the continuous reception of signals is avoided, thereby reducing correlation. The amount of computation of the operation, which in turn reduces the cost and power consumption of the NB-IoT for the main synchronization process, and ultimately improves the NB-IoT The efficiency of synchronization.

Based on the same inventive concept, an embodiment of the present invention further provides a device for determining a symbol position of a primary synchronization signal, and FIG. 13 is a schematic structural diagram of a device for determining a symbol position of a primary synchronization signal according to an embodiment of the present invention, as shown in FIG. The device includes: a sampling module 131, a processing module 132, a first determining module 133, an arithmetic module 134, and a second determining module 135;

The sampling module 131 is configured to process the received radio frequency signal to obtain a digital baseband signal, and sample the digital baseband signal to obtain a sampling signal. The processing module 132 is configured to process the sampling signal to obtain a sampling signal in the K sub-samples. a cumulative power value of the frame; the first determining module 133 is configured to determine a maximum value of the sampled signals in the accumulated power values of the K subframes as a first accumulated power value, and determine a subframe position corresponding to the first accumulated power value as a sub-frame position of the NPSS; the operation module 134 is configured to perform a correlation operation between the pre-configured NPSS and the sampling signal according to the subframe position of the NPSS to obtain each correlation value; and the second determining module 135 is configured to determine according to each correlation value. The symbol position of the NPSS.

In order to obtain the cumulative power value of the sampled signal in the K subframes, in an optional embodiment, the processing module 132 includes: a processing submodule configured to process the sampling signal according to a preset algorithm to obtain a sampling signal. The energy of K subframes in a radio frame; the accumulating filter sub-module is configured to accumulate and filter the energy of the K subframes of the sampled signal in a radio frame according to the first preset frame number to obtain the accumulation of the sampled signal in the K subframes. Power value.

In an optional embodiment, the processing submodule is configured to perform a conjugate point multiplication operation on the sampled signal to obtain conjugates of the sampled signal, in order to obtain the energy of the K subframes of the sampled signal in a radio frame. The result of the point multiplication operation; the K sets of conjugate point multiplication results are selected from the conjugate point multiplication results of the sampled signals, and the K sets of conjugate point multiplication results are respectively subjected to the cumulative averaging operation to obtain the sampled signals in one radio frame. The energy of K subframes.

Since the terminal and the system perform frequency synchronization in addition to time synchronization in the initial synchronization process, frequency offset is caused in the process of frequency synchronization, and in order to eliminate the frequency offset, in an optional embodiment, the above apparatus further includes a compensation module configured to determine a maximum value of the cumulative power values of the sampled signals in the K subframes as a first cumulative power value, and determine a subframe position corresponding to the first accumulated power value as a sub-narrow primary synchronization signal NPSS After the frame position, determining a first frequency offset of the sampling signal according to the subframe position corresponding to the first accumulated power value; performing frequency offset compensation on the sampling signal according to the first frequency offset.

In an optional embodiment, the apparatus further includes: an adjusting module configured to perform frequency offset compensation on the sampling signal according to the first frequency offset, after the sampling signal is in the There are at least two peaks in the accumulated power values of the K subframes, and the power difference between the peak value and the maximum value of the sampled signals in the accumulated power values of the K subframes is less than or equal to the first preset threshold value, and When the time difference between the peak value and the sampling signal is greater than or equal to the second preset threshold value in the cumulative power value of the K subframes, when the first frequency offset is greater than the absolute value of the preset operation threshold, Determining, as a first accumulated power value, a first peak after the maximum value of the accumulated power values of the K subframes; and at least two peaks in the cumulative power value of the sampled signals in the K subframes, and the peak value The power difference between the maximum value of the accumulated power values of the K subframes is less than or equal to the first preset threshold value, and the peak value and the maximum value of the sampled signal in the accumulated power values of the K subframes between When the time difference is greater than or equal to the second preset threshold, when the first frequency offset is less than the inverse of the absolute value of the preset operation threshold, the maximum value of the sampled signal in the cumulative power values of the K subframes The previous first peak is determined as the first accumulated power value, and the triggering first determining module returns to perform the determination of the subframe position corresponding to the first cumulative power value as the subframe position of the NPSS.

In an optional embodiment, the operation module 134 is specifically configured to obtain a preset score, because the frequency offset is caused in the initial synchronization process. The frequency offset value of the number of segments; the frequency offset value of the sampled signal is respectively subjected to frequency offset compensation processing to obtain a processed sample signal of a preset number of segments; according to the subframe position of the NPSS, the pre-configuration is performed according to the subframe position of the NPSS The NPSS is correlated with the processed sampled signal to obtain correlation values, and each correlation value is accumulated and filtered according to the second preset frame number to obtain a power value corresponding to each correlation value.

Here, the second determining module 135 determines the symbol position of the NPSS according to each correlation value, and at least the following two manners are adopted: in the first manner, according to the size of each correlation value, the subframe corresponding to the maximum value among the correlation values may be The symbol position is determined as the symbol position of the NPSS; the second method may determine the symbol position of the NPSS according to the following manner. In an optional embodiment, the second determining module is specifically configured to correspond to each related value. A preset number of peaks are selected from the power values; an average value of the power values other than the preset number of peaks is calculated among the power values corresponding to the correlation values; and the power value corresponding to each correlation value is selected to be greater than the average value The power value of the product of the preset decision threshold is determined as the symbol position of the NPSS in the symbol position in the subframe corresponding to the maximum value of the selected power values.

In practical applications, the sampling module 131, the processing module 132, the first determining module 133, the computing module 134, the second determining module 135, the processing submodule, the accumulating filtering submodule, the compensating module, and the adjusting module may all be provided by a processor located in the device. For example, a CPU, a microprocessor (MPU, Microprocessor Unit), an application specific integrated circuit (ASIC), or a Field-Programmable Gate Array (FPGA) are implemented.

This embodiment describes a computer readable storage medium, which may be a read only memory (ROM) (for example, a read only memory, a FLASH memory, a transfer device, etc.), a magnetic storage medium (for example, a magnetic tape, a magnetic disk drive, etc.). Optical storage medium (eg, CD-ROM, DVD-ROM, paper card, paper tape, etc.) and other well-known types of program memory; computer-readable storage medium stores computer-executable instructions that, when executed, cause At least one processor performs the following operations:

Processing the received RF signal to obtain a digital baseband signal, sampling the digital baseband signal to obtain a sampled signal; processing the sampled signal to obtain a cumulative power value of the sampled signal in K subframes; according to a preset rule, the sampled signal is Determined among the cumulative power values of K subframes a first cumulative power value, the subframe position corresponding to the first accumulated power value is determined as a subframe position of the NPSS; and the pre-configured NPSS is correlated with the sampling signal according to the subframe position of the NPSS to obtain each correlation value; The symbol position of the NPSS is determined based on each correlation value.

In other words, the computer readable storage medium provided by the embodiment of the present invention has a computer program stored thereon, and when the computer program is executed by the processor, the steps of any method of the embodiment of the present invention are implemented.

The method for determining the symbol position of the primary synchronization signal provided by the embodiment of the present invention firstly processes the received radio frequency signal to obtain a digital baseband signal, samples the digital baseband signal to obtain a sampling signal, and then processes the sampled signal to obtain a sampled signal. The cumulative power value of the sampled signal in the K subframes, the maximum value of the sampled signal in the cumulative power values of the K subframes is determined as the first cumulative power value, and the subframe position corresponding to the first accumulated power value is determined as the child of the NPSS The position of the frame, so that the approximate position of the time point of the NPSS to be synchronized can be known. Finally, according to the subframe position of the NPSS, the pre-configured NPSS is correlated with the sampled signal to obtain correlation values, according to the correlation values. Determining the symbol position of the NPSS; that is, the embodiment of the present invention obtains the cumulative power value of the sampled signal in the K subframes by processing the sampled signal, and the corresponding NPSS can be determined according to the accumulated power value of the sampled signal in the K subframes. The position of the sub-frame, then, the correlation between the NPSS and the sampling signal of the sub-frame where the non-NPSS is located is avoided. And avoids discontinuous reception signal, this can reduce the amount of calculation for the correlation calculation, thereby reducing the cost and power for NB-IoT primary synchronization process, ultimately, improve the efficiency of NB-IoT main synchronization.

It should be noted here that the description of the above device embodiment items is similar to the above method description, and has the same beneficial effects as the method embodiments, and therefore will not be described again. For the technical details that are not disclosed in the embodiments of the present invention, those skilled in the art should refer to the description of the method embodiments of the present invention, and the details are not described herein.

What needs to be pointed out here is:

It is to be understood that the phrase "one embodiment" or "an embodiment" or "an" Thus, "in one embodiment" or "in an embodiment" or "an" In addition, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that various embodiments of the invention The size of the sequence numbers of the above processes does not mean that the order of execution is sequential, and the order of execution of the processes should be determined by its function and internal logic, and should not be construed as limiting the implementation process of the embodiments of the present invention. The serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments.

It is to be understood that the term "comprises", "comprising", or any other variants thereof, is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes those elements. It also includes other elements that are not explicitly listed, or elements that are inherent to such a process, method, article, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, such as: multiple units or components may be combined, or Can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, or direct coupling, or communication connection of the components shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, and may be electrical, mechanical or other forms. of.

The units described above as separate components may or may not be physically separated, and the components displayed as the unit may or may not be physical units; they may be located in one place or distributed on multiple network units; Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated into one unit; The unit can be implemented in the form of hardware or in the form of hardware plus software functional units.

It will be understood by those skilled in the art that all or part of the steps of implementing the foregoing method embodiments may be performed by hardware related to program instructions. The foregoing program may be stored in a computer readable storage medium, and when executed, the program includes The foregoing steps of the method embodiment; and the foregoing storage medium includes: a removable storage device, a ROM, a magnetic disk, or an optical disk, and the like, which can store program codes.

Alternatively, the above-described integrated unit of the present invention may be stored in a computer readable storage medium if it is implemented in the form of a software function module and sold or used as a standalone product. Based on such understanding, the technical solution of the embodiments of the present invention may be embodied in the form of a software product in essence or in the form of a software product stored in a storage medium, including a plurality of instructions. A computer device (which may be a personal computer, server, or network device, etc.) is caused to perform all or part of the methods described in various embodiments of the present invention. The foregoing storage medium includes various media that can store program codes, such as a mobile storage device, a ROM, a magnetic disk, or an optical disk.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Industrial applicability

The solution provided by the embodiment of the present invention processes the received radio frequency signal to obtain a digital baseband signal, samples the digital baseband signal to obtain a sampling signal, and processes the sampled signal to obtain a cumulative power value of the sampled signal in K subframes, which will be sampled. The maximum value of the accumulated power values of the K subframes is determined as the first accumulated power value, and the subframe position corresponding to the first accumulated power value is determined as the subframe position of the NPSS, so that the NPSS needs to be synchronized. The approximate position of the time point. Finally, according to the subframe position of the NPSS, the pre-configured NPSS is correlated with the sampling signal to obtain each correlation value, and the symbol position of the NPSS is determined according to each correlation value; that is, the present invention The embodiment obtains the accumulated power value of the sampled signal in the K subframes by processing the sampled signal, and determines the subframe position of the corresponding NPSS according to the accumulated power value of the sampled signal in the K subframes, thereby avoiding the NPSS and the non-negative The sampling signal of the sub-frame in which the NPSS is located performs correlation operations, and avoids continuous reception of signals, so that the reduction can be reduced. Calculating an amount of correlation calculation, thereby reducing the cost and power for NB-IoT primary synchronization process, ultimately, improve the efficiency of NB-IoT main synchronization.

Claims

A method for determining a symbol position of a primary synchronization signal, comprising:

Processing the received radio frequency signal to obtain a digital baseband signal, and sampling the digital baseband signal to obtain a sampling signal;

Processing the sampled signal to obtain a cumulative power value of the sampled signal in K subframes;

Determining, as a first accumulated power value, a maximum value of the accumulated power values of the sampled signals in the K subframes, and determining a subframe position corresponding to the first accumulated power value as a subframe position of the narrowband primary synchronization signal NPSS;

Performing a correlation operation between the pre-configured NPSS and the sampling signal according to the subframe position of the NPSS to obtain each correlation value;

Determining the symbol position of the NPSS according to the correlation values.
The method according to claim 1, wherein said processing said sampling signal to obtain an accumulated power value of said sampled signal in K subframes comprises:

Processing the sampled signal according to a preset algorithm to obtain energy of the K subframes of the sampled signal in one radio frame;

Accumulating and filtering the energy of the K subframes of the sampled signal in a radio frame according to the first preset number of frames to obtain an accumulated power value of the sampled signal in the K subframes.
The method according to claim 2, wherein the processing of the sampled signal according to a preset algorithm to obtain energy of K subframes of the sampled signal in a radio frame comprises:

Performing a conjugate point multiplication operation on the sampling signal to obtain a conjugate point multiplication result of the sampling signal;

Selecting K sets of conjugate point multiplication results from the conjugate point multiplication results of the sampled signals, and performing cumulative averaging operations on the K sets of conjugate point multiplication results to obtain the sampled signals in a radio frame. The energy of a sub-frame.
The method according to claim 1, wherein a maximum value of said sampled signals in cumulative power values of K subframes is determined as a first cumulative power value, said first cumulative power value After the corresponding subframe position is determined as the subframe position of the NPSS, the method further includes:

Determining, according to the subframe position corresponding to the first accumulated power value, a first frequency offset of the sampling signal;

Performing frequency offset compensation on the sampling signal according to the first frequency offset.
The method of claim 4, wherein after the frequency offset compensation is performed on the sampled signal according to the first frequency offset, the method further comprises:

Having at least two peaks in the cumulative power value of the K samples in the sampled signal, and the power difference between the peak and the maximum value of the sampled signal in the cumulative power values of the K subframes is less than or equal to When the first preset threshold is used, and the time difference between the peak value and the maximum value of the sampling signal in the accumulated power values of the K subframes is greater than or equal to the second preset threshold value, When the first frequency offset is greater than the absolute value of the preset operation threshold, the first peak after the maximum value of the accumulated power values of the K subframes is determined as the first accumulated power value ;

Having at least two peaks in the cumulative power value of the K samples in the sampled signal, and the power difference between the peak and the maximum value of the sampled signal in the cumulative power values of the K subframes is less than or equal to When the first preset threshold is used, and the time difference between the peak value and the maximum value of the sampling signal in the accumulated power values of the K subframes is greater than or equal to the second preset threshold value, When the first frequency offset is smaller than the inverse of the absolute value of the preset operation threshold, the first peak before the maximum value of the accumulated power values of the K subframes is determined as the first And an accumulated power value, returning to perform the step of determining the subframe position corresponding to the first accumulated power value as the subframe position of the NPSS.
The method according to claim 1, wherein the correlating the pre-configured NPSS with the sampling signal according to the subframe position of the NPSS to obtain respective correlation values, including:

Obtain a frequency offset value of the preset number of segments;

And performing frequency offset compensation processing on the sampling signal according to the frequency offset value of the preset number of segments, to obtain the processed sampling signal of the preset number of segments;

Determining the pre-configured NPSS with the pre-preparation according to the subframe position of the NPSS The segmented number of processed sampled signals are subjected to correlation operations to obtain the correlation values.
The method according to claim 6, wherein determining the symbol position of the NPSS according to the correlation values comprises:

And accumulating and filtering the correlation values according to the second preset frame number to obtain power values corresponding to the correlation values;

Selecting a preset number of peaks from the power values corresponding to the correlation values;

Calculating an average value of the power values other than the preset number of peaks among the power values corresponding to the correlation values;

And selecting, in the power value corresponding to each of the correlation values, a power value that is greater than a product of the average value and a preset decision threshold, and determining a symbol position in a subframe corresponding to a maximum value of the selected power values as the The symbol position of the NPSS.
A device for determining a symbol position of a primary synchronization signal, comprising:

a sampling module configured to process the received radio frequency signal to obtain a digital baseband signal, and sample the digital baseband signal to obtain a sampling signal;

a processing module configured to process the sampled signal to obtain a cumulative power value of the sampled signal in K subframes;

a first determining module, configured to determine a maximum value of the sampling signal in the accumulated power values of the K subframes as a first accumulated power value, and determine a subframe position corresponding to the first accumulated power value as the narrowband The subframe position of the primary synchronization signal NPSS;

The operation module is configured to perform a correlation operation between the pre-configured NPSS and the sampling signal according to the subframe position of the NPSS to obtain each correlation value;

And a second determining module, configured to determine a symbol position of the NPSS according to the correlation values.
The device of claim 8, wherein the processing module comprises:

Processing the sub-module, configured to process the sampled signal according to a preset algorithm, to obtain energy of the K subframes of the sampled signal in a radio frame;

An accumulation filter sub-module configured to encode the sampled signal in K frames in a radio frame The energy is accumulated and filtered according to the first preset frame number to obtain the accumulated power value of the sampled signal in the K subframes.
The apparatus according to claim 9, wherein the processing submodule is configured to perform a conjugate point multiplication operation on the sampling signal to obtain a conjugate point multiplication result of the sampling signal; and from the sampling signal The K-group conjugate point multiplication result is selected from each of the conjugate point multiplication results, and the K-group conjugate point multiplication result is subjected to an accumulated averaging operation to obtain energy of the K-subframes of the sampled signal in one radio frame.
The apparatus of claim 8 wherein said apparatus further comprises:

a compensation module, configured to determine a maximum value of the accumulated power values of the sampled signals in the K subframes as a first accumulated power value, and determine a subframe position corresponding to the first accumulated power value as the NPSS After the subframe position, determining, according to the subframe position corresponding to the first accumulated power value, a first frequency offset of the sampling signal; and performing frequency offset compensation on the sampling signal according to the first frequency offset.
The apparatus of claim 11 wherein said apparatus further comprises:

And an adjusting module, configured to perform frequency offset compensation on the sampling signal according to the first frequency offset, wherein at least two peaks exist in the accumulated power value of the sampling signal in the K subframes, and the peak value is And when the power difference between the maximum values of the accumulated power values of the K subframes is less than or equal to the first preset threshold, and the peak value and the sampling signal are in the accumulated power values of the K subframes When the time difference between the maximum values is greater than or equal to the second preset threshold, and the first frequency offset is greater than the absolute value of the preset operation threshold, the sampling signal is in K subframes The first peak after the maximum value of the accumulated power values is determined as the first accumulated power value; at the two accumulated peaks in the accumulated power values of the K subframes, and the peak and the peak And determining, when the power difference between the maximum values of the accumulated power values of the K subframes is less than or equal to the first preset threshold, and the accumulated power value of the peak and the sampling signal in the K subframes Time difference between the maximum values in When the second preset threshold is greater than or equal to the second preset threshold, and the first frequency offset is less than the inverse of the absolute value of the preset operation threshold, the sampling signal is in the cumulative power value of the K subframes. The first peak before the maximum value is determined as the first accumulated power value, triggering the first determining module to return to perform determining the subframe position corresponding to the first accumulated power value as the subframe position of the NPSS .
The apparatus according to claim 8, wherein the operation module is configured to acquire a frequency offset value of the preset number of segments; and separately frequency offset the sampling signal according to the frequency offset value of the preset number of segments Compensating processing, obtaining the processed sampling signal of the preset number of segments; and processing the pre-configured NPSS and the preset number of segments of the processed sampling signal according to the subframe position of the NPSS Correlation operations are performed to obtain the respective correlation values.
The device according to claim 13, wherein the second determining module is configured to accumulate and filter the correlation values according to the second preset frame number to obtain power values corresponding to the correlation values; And selecting a preset number of peaks from the power values corresponding to the correlation values; and calculating, in the power values corresponding to the correlation values, an average value of power values other than the preset number of peak values; Determining, by the power value corresponding to each correlation value, a power value greater than a product of the average value and a preset decision threshold, and determining a symbol position in a subframe corresponding to a maximum value of the selected power values as the NPSS Symbol location.
A computer readable storage medium having stored thereon a computer program, the computer program being executed by a processor to perform the steps of the method of any one of claims 1 to 7.