CN113301631A

CN113301631A - Scanning method, terminal and storage medium

Info

Publication number: CN113301631A
Application number: CN202010111398.1A
Authority: CN
Inventors: 刘君
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-02-24
Filing date: 2020-02-24
Publication date: 2021-08-24
Anticipated expiration: 2040-02-24
Also published as: CN113301631B; WO2021169716A1

Abstract

The application discloses a scanning method, a terminal and a storage medium. The method comprises the following steps: receiving a downlink signal; calculating a power spectrum of the downlink signal based on the received downlink signal; determining more than one potential grid frequency from the power spectrum and a prescribed threshold; and performing frequency domain correlation detection on the received downlink signal based on a local synchronization sequence with reference to the more than one potential grid frequency to acquire an effective grid frequency.

Description

Scanning method, terminal and storage medium

Technical Field

The present application relates to the field of communications technologies, and in particular, to a scanning method, a terminal, and a storage medium.

Background

More frequency resources are planned in a Long Term Evolution (LTE) system and a New Radio over the air (NR) system for 5th Generation (5G) mobile communication, so as to meet the increasing data service requirements of a terminal, which brings a great challenge to frequency point scanning of the terminal, and the terminal needs to complete scanning after being started up with a Long time, which affects communication efficiency.

Disclosure of Invention

In view of this, embodiments of the present application provide a scanning method, a terminal and a storage medium, so as to at least solve the problem in the related art that the communication efficiency is affected because the terminal needs to complete scanning after being powered on.

The technical scheme of the embodiment of the application is realized as follows:

the embodiment of the application provides a scanning method, which comprises the following steps:

receiving a downlink signal;

calculating a power spectrum of the downlink signal based on the received downlink signal;

determining more than one potential grid frequency from the power spectrum and a prescribed threshold; and

and performing frequency domain correlation detection on the received downlink signal based on a local synchronization sequence by referring to the more than one potential grid frequency to acquire an effective grid frequency.

In the above scheme, the specified threshold is obtained based on a minimum possible bandwidth determined by a 3GPP specification.

In the above scheme, the frequency domain correlation detection uses an overlap-and-hold method or an overlap-and-add method.

In the above scheme, the method further comprises the following steps:

and preprocessing the local synchronization sequence.

In the foregoing solution, in the preprocessing, the local synchronization sequence is frequency compensated based on the subcarrier interval of the downlink signal and the corresponding grid frequency.

In the above scheme, in the preprocessing, the local synchronization sequence is subjected to low-pass filtering.

In the above scheme, in the preprocessing, the local synchronization sequence lines of at least two numbers are added and combined.

An embodiment of the present application further provides a terminal, including:

a receiving unit, configured to receive a downlink signal;

a calculating unit, configured to calculate a power spectrum of the downlink signal based on the received downlink signal;

a determining unit for determining more than one potential grid frequency according to the power spectrum and a prescribed threshold value;

and the detection unit is used for performing frequency domain correlation detection on the received downlink signal based on a local synchronization sequence by referring to the more than one potential grid frequency so as to acquire an effective grid frequency.

The embodiment of the present application further provides a terminal, which includes: a communication interface, a processor and a memory for storing a computer program capable of running on the processor,

the processor is configured to execute the steps corresponding to any one of the methods when the computer program is run.

Embodiments of the present application also provide a storage medium having a computer program stored thereon, where the computer program is executed by a processor to implement the steps of any one of the above methods.

In the embodiment of the application, the terminal calculates the power spectrum of the downlink signal based on the received downlink signal, determines more than one potential grid frequency according to the power spectrum of the downlink signal and a specified threshold, and performs frequency domain correlation detection on the received downlink signal based on the local synchronization sequence by referring to the determined more than one potential grid frequency, thereby determining an effective grid frequency from the more than one potential grid frequency and completing scanning. According to the scheme of the embodiment of the application, the scanning speed of the terminal in the network searching process is improved, so that the terminal can rapidly detect the effective cell to reside, and especially under the scene that the downlink signal power is high, the scheme of the embodiment of the application is beneficial for the terminal to detect the effective cell in a very short time, and the communication efficiency of the terminal is improved.

Drawings

Fig. 1 is a schematic flow chart illustrating an implementation of a scanning method according to an embodiment of the present application;

fig. 2 is a schematic diagram of a flow of implementing power spectrum estimation on a downlink signal according to an embodiment of the present disclosure;

fig. 3 is a schematic flow chart illustrating an implementation of a scanning method according to an embodiment of the present application;

fig. 4 is a schematic diagram illustrating an implementation principle of frequency domain correlation detection by using an overlap-and-reserve method according to an embodiment of the present application;

fig. 5 is a diagram illustrating examples of a downlink synchronization sequence and a local synchronization sequence provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a terminal according to an embodiment of the present application;

fig. 7 is a schematic diagram of a hardware composition structure of a terminal according to an embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

The technical means described in the embodiments of the present application may be arbitrarily combined without conflict.

When the terminal is just started, because the frequency point information of the surrounding cells cannot be predicted, the network searching needs to be carried out through scanning, and therefore cell residence is completed. In the related technology, a terminal usually detects possible frequency points one by one in a possible frequency band based on time domain related detection or frequency domain related detection of a synchronization sequence signal, and needs to try multiple numbered local synchronization sequences on the same frequency point one by one to finally determine effective frequency points meeting reporting conditions, thereby further completing cell residence. With the increasing demand of the terminal for data service, currently, more frequency resources are planned in the LTE system and the 5G NR system to meet the increasing demand of the terminal for data service. For example, in the NR FR2 frequency band, that is, the millimeter wave frequency band of 5G, the system bandwidth is as high as 400MHz, so that the time consumed by frequency point scanning is greatly increased when the terminal in the related art starts up to search for a network, and in an extreme case, even several minutes are required to search for a suitable cell, which seriously affects the communication efficiency of the terminal.

Based on this, in various embodiments of the present application, a terminal calculates a power spectrum of a downlink signal based on a received downlink signal, determines one or more potential grid frequencies according to the power spectrum of the downlink signal and a specified threshold, and performs frequency domain correlation detection on the received downlink signal based on a local synchronization sequence, thereby determining an effective grid frequency from the one or more potential grid frequencies, and completing scanning, thereby increasing a scanning speed of the terminal in a network searching process, so that the terminal can quickly detect an effective cell to camp on, and particularly in a scene with high downlink signal power, the scheme of the embodiments of the present application facilitates the terminal to detect the effective cell in a very short time, and improves communication efficiency of the terminal.

The present application will be described in further detail with reference to the following drawings and specific embodiments.

Fig. 1 shows an implementation flow of a scanning method provided in an embodiment of the present application, where an execution subject of the implementation flow is a terminal. Referring to fig. 1, the method includes:

step 101: and receiving a downlink signal.

Step 102: and calculating the power spectrum of the downlink signal based on the received downlink signal.

Here, the terminal opens the downlink channel of the radio frequency module in the power-on state, and receives the downlink signal of the network side. When the terminal receives the downlink signal, the length of the received data is the minimum period of the downlink signal plus an Orthogonal Frequency Division Multiplexing (OFDM) symbol length, and the receiving bandwidth is determined by the following formula:

rx_bandwith＝fft_length_max*SCS

wherein rx _ bandwidth is a receiving bandwidth, FFT-length _ max is a maximum length of Fast Fourier Transform (FFT), SCS is a Sub-Carrier Space (Sub-Carrier Space) of a downlink signal, in an LTE system, the Sub-Carrier Space of the downlink signal is fixed to 15KHz, and in an NR system, the Sub-Carrier Space of the downlink signal may be 15KHz, 30KHz, 120KHz, or 240 KHz. The carrier center frequency of the downlink signal is the frequency corresponding to the center point of the FFT scanning interval, and can be determined by the following formula:

rx _ center _ frequency (i) is band _ start + FFT _ length SCS/2, where rx _ center _ frequency (i) is the corresponding carrier center frequency, band _ start is the start of the frequency band, and FFT _ length is the corresponding FFT length.

As shown in fig. 2, the terminal performs FFT conversion on the received time domain data, so as to convert the time domain data into frequency domain data partitioned according to the FFT length, and then superimposes the partitioned frequency domain data in the frequency domain, and performs smooth filtering on the superimposed power spectrum, so as to estimate the power spectrum of the downlink signal.

The power spectrum can be smoothed by using a smoothing filter with average filtering of n-th order:

in the above equation, the value of n is determined by the corresponding FFT length.

Step 103: more than one potential grid frequency is determined from the power spectrum and a prescribed threshold.

Here, the terminal scans within the power spectrum of the downlink signal and determines one or more potential grid frequencies based on a defined threshold.

Specifically, the terminal first determines a portion of the power spectrum energy in the power spectrum that exceeds a set threshold, thereby determining a frequency bandwidth in which the power spectrum energy in the power spectrum continuously exceeds the set threshold. The set threshold is configured in advance by the terminal side, in the embodiment of the application, when the set threshold is lower, the frequency point detection sensitivity of the terminal can be improved, the occurrence of the missed detection condition is reduced, and when the set threshold is higher, the frequency point detection accuracy of the terminal can be improved, and the occurrence of the false detection condition is reduced.

In practical applications, the set threshold may be configured to-85 dBm, for example.

In one embodiment, the prescribed threshold is derived based on the smallest possible bandwidth determined in the 3GPP specification. In the 3GPP protocol, it is specified that each band supports different bandwidths, for example, one band supports bandwidths of 5MHz, 10MHz, 20MHz, and 100MHz, and then the minimum bandwidth supported by the band is 5 MHz. Here, in the process of scanning by the terminal, for a frequency band currently scanned by the terminal, the terminal determines a minimum bandwidth supported by the frequency band, that is, a minimum possible bandwidth corresponding to the frequency band in the 3GPP specification, and for convenience of description, the minimum bandwidth supported by the frequency band, that is, the minimum possible bandwidth is referred to as a "second bandwidth".

Further, when scanning is performed based on frequency domain correlation detection, after determining the minimum bandwidth supported by the currently scanned frequency band, the terminal needs to convert the minimum bandwidth into corresponding FFT points, so as to multiply the sequence in the frequency domain.

After determining the first bandwidth and the second bandwidth, the terminal determines whether the width of the first bandwidth can reach or approach a certain proportion of the second bandwidth by calculating a ratio of the first bandwidth to the second bandwidth, that is, whether the ratio is greater than a set threshold (for example, the set threshold may be set to 90%), and when the ratio is greater than the set threshold, the terminal determines the raster frequency in the currently scanned frequency band as the potential raster frequency.

Here, the raster frequency is understood to be a center frequency of a signal bandwidth in a frequency band, and generally, there are several center frequencies in one frequency band, that is, there are multiple raster frequencies in one frequency band, and once the terminal determines that the ratio of the first bandwidth to the second bandwidth is greater than the set threshold, the terminal determines all raster frequencies in the currently scanned frequency band as potential raster frequencies.

Step 104: and performing frequency domain correlation detection on the received downlink signal based on a local synchronization sequence by referring to the more than one potential grid frequency to acquire an effective grid frequency.

Specifically, for each potential grid frequency, the terminal determines whether a correlation peak corresponding to the potential grid frequency exceeds a corresponding threshold through a time domain correlation detection method or a frequency domain correlation detection method, and if the correlation peak corresponding to the potential grid frequency exceeds the corresponding threshold, the terminal determines that the potential grid frequency corresponds to a frequency point meeting a set reporting condition, and determines the potential grid frequency as an effective grid frequency. Here, the set reporting condition can represent that the correlation peak of the corresponding grid frequency exceeds the set threshold.

In one embodiment, the length of the local synchronization sequence may be 128 points. Here, when the frequency domain performs convolution operation on the downlink synchronization sequence and the local synchronization sequence, the least effective point of the FFT, that is, 128 points, is used as the sequence length, and compared with the related art in which the number of FFT points is directly used as the sequence length to perform convolution operation, the scheme effectively reduces the operation amount.

Here, the terminal combines the power spectrum detection and the frequency domain correlation detection to determine whether the frequency point corresponding to the grid frequency meets the set reporting condition. Compared with a time domain correlation detection method, the frequency domain correlation detection method has the advantages that the calculation amount is greatly reduced, and the scanning efficiency of the terminal can be greatly improved.

In practical application, a frequency domain correlation detection process is executed by a physical layer of a terminal, the physical layer of the terminal reports the determined frequency point (namely, the effective grid frequency) meeting the reporting condition to an application layer of the terminal based on a corresponding detection result, and then subsequent judgment operation is executed by the application layer of the terminal to finally determine a frequency point, and the terminal completes cell residence on a cell corresponding to the frequency point.

Fig. 3 is a schematic flow chart illustrating an implementation of a scanning method provided in an application embodiment of the present application, and with reference to fig. 3:

step 301: the terminal initiates a scan of the frequency band.

Step 302: and the terminal receives a downlink signal of the network side.

Step 303: the terminal determines the power spectrum of the downlink signal.

Step 304: the terminal determines whether a potential raster frequency exists in the currently scanned frequency band by combining the power spectrum and a predetermined threshold, if the determination result is yes, step 305 is executed, and if the determination result is no, the terminal returns to execute step 302 for the next scanned frequency band.

Step 305: and the terminal completes the frequency domain correlation detection of the potential grid frequency in the currently scanned frequency band through the frequency domain correlation detection.

Step 306: when the detection result indicates that the frequency points meeting the set reporting condition exist in the currently scanned frequency band, the physical layer of the terminal reports the frequency points meeting the set reporting condition to the application layer of the terminal.

The frequency domain correlation detection in step 305 may be performed by an overlap-and-hold method or an overlap-and-add method, and the overlap-and-hold method will be described below as an example. Fig. 4 shows the implementation principle of frequency domain correlation detection using overlap-and-hold method. Referring to fig. 4, the received downlink signal is subjected to overlapping segmentation, the length of each segment is N, the length of the overlapping portion between each two segments is equal to M, the mth segment of time domain downlink signal is recorded as f (M), fast fourier transform is performed on f (M) to obtain FFT output, then, according to potential grid frequency obtained by power spectrum calculation, convolution operation is performed on a frequency domain portion corresponding to the FFT output and a local synchronization sequence to obtain a maximum value, a frequency point meeting a set reporting condition exists in a frequency band in which a detection result represents that the currently scanned frequency band, an effective grid frequency is obtained, and a frequency point meeting the set reporting condition is reported.

As described above, in the present invention, before the frequency domain correlation detection, the initial search is performed based on the power spectrum calculation to obtain the potential grid frequency, that is, the approximate possible position of the effective grid frequency, and then the frequency domain correlation detection is performed with reference to the potential grid frequency, so that the computation amount of the frequency domain correlation detection can be greatly reduced compared with the prior art, thereby achieving the technical effect of quickly searching the residential cell.

Further, in one embodiment, the method further comprises the steps of:

and preprocessing the local synchronization sequence.

Here, the terminal performs preprocessing on the local synchronization sequence before performing the sequence convolution in the frequency domain. Specifically, in one embodiment, in the preprocessing, the local synchronization sequence is frequency compensated based on a subcarrier interval of the downlink signal and a corresponding grid frequency.

In practical applications, the downlink synchronization sequence and the local synchronization sequence are not always aligned. Taking fig. 5 as an example, the subcarrier spacing center frequency point of the downlink signal is equal to 15KHz × N, and the center frequency point of the grid frequency is equal to 100KHz × M, although the downlink synchronization sequence can be aligned with the local synchronization sequence at the center frequency point N of the grid frequency, the local synchronization sequence differs from the center frequency point of the grid frequency by 15/2KHz at the frequency point N-1 of the grid frequency, and differs from the center frequency point of the grid frequency by-15/2 KHz at the frequency point N +1 of the grid frequency, which means that the downlink synchronization sequence and the local synchronization sequence cannot be always aligned, which may lead to the condition of missed detection of the frequency point, and reduce the scanning sensitivity. Based on this, the terminal performs frequency compensation on the local synchronization sequence to eliminate the frequency offset between the local synchronization sequence and the downlink synchronization sequence.

Specifically, the local synchronization sequence is frequency compensated based on the following formula:

wherein, pss _ fshift (i) is the local synchronization sequence after frequency compensation, pss _ local (i) is the original local synchronization sequence, and raster (i) is the center frequency of the downlink signal, i.e. the grid frequency.

In one embodiment, in the preprocessing, the local synchronization sequence is low-pass filtered.

In practical applications, since the synchronization sequence needs multiple sampling under several scenarios, interference between subcarriers may be generated, and thus a window effect in a time domain may be caused, the local synchronization sequence is subjected to a low-pass filtering process, so as to eliminate the interference between subcarriers.

Specifically, the local synchronization sequence is low-pass filtered based on the following formula:

pss_local＝pss_frequency*fft(lpf-sequence)

wherein, pss _ local is the local synchronization sequence after the low-pass filtering processing, pss _ frequency is the original local synchronization sequence, and fft (lpf _ sequence) is the low-pass filter coefficient.

In an embodiment, in the preprocessing, at least two numbered local synchronization sequence lines are additively combined.

For the LTE system and the NR system, the local synchronization sequence has three numbers, and in the correlation technique, it is necessary to perform linear correlation between the downlink synchronization sequence and the local synchronization sequence corresponding to each of the three numbers in sequence, and then find a correlation peak in a time domain. However, in practice, the frequency point scanning does not pay attention to the number of the local synchronization sequence, but pays attention to whether the frequency point is a frequency point suitable for the cell where the terminal resides. Therefore, here, the local synchronization sequences of at least two numbers are added to realize the merging of the local synchronization sequences, thereby reducing the amount of computation in the frequency domain correlation detection.

In practical applications, three numbered local synchronization sequences may be added and combined, specifically:

wherein, the pss _ combination is the combined local synchronization sequence, and the pss _ sequence (i) is the local synchronization sequence numbered i. Therefore, the calculation amount can be reduced by two thirds in the frequency domain correlation detection, and the frequency point scanning result is not influenced.

It should be noted that the frequency point scanning method provided in the embodiment of the present application may be compatible with multiple wireless broadband systems such as an LTE system, an NR FR1 system, and an NR FR2 system, and is suitable for a network searching process of a terminal in a startup network searching process in a corresponding wireless broadband system and in other scenarios.

In order to implement the cell camping method according to the embodiment of the present application, an embodiment of the present application further provides a terminal, as shown in fig. 6, including:

a receiving unit 61, configured to receive a downlink signal;

a calculating unit 62, configured to calculate a power spectrum of the downlink signal based on the received downlink signal;

a determining unit 63 for determining more than one potential grid frequency from the power spectrum and a prescribed threshold;

a detecting unit 64, configured to perform frequency domain correlation detection on the received downlink signal based on a local synchronization sequence with reference to the more than one potential grid frequency, so as to obtain an effective grid frequency.

In one embodiment, the prescribed threshold is derived based on the smallest possible bandwidth determined by the 3GPP specifications.

In one embodiment, the frequency domain correlation detection by the detection unit 64 uses an overlap-and-hold method or an overlap-and-add method.

In one embodiment, further comprising:

and the preprocessing unit is used for preprocessing the local synchronization sequence.

In one embodiment, the preprocessing unit performs frequency compensation on the local synchronization sequence based on a subcarrier interval of the downlink signal and a corresponding grid frequency.

In one embodiment, the pre-processing unit low-pass filters the local synchronization sequence.

In one embodiment, the pre-processing unit additively combines at least two numbered rows of the local synchronization sequence.

In practical applications, the receiving unit 61 may be implemented by a communication interface in the terminal, and the calculating unit 62, the determining unit 63, the detecting unit 64 and the preprocessing unit may be implemented by a processor in the terminal. Of course, the processor needs to run the program stored in the memory to realize the functions of the above-described program modules.

It should be noted that the terminal provided in the embodiment of fig. 6 is only exemplified by the division of the program modules, and in practical applications, the above processing distribution may be completed by different program modules according to needs, that is, the internal structure of the terminal is divided into different program modules to complete all or part of the above-described processing. In addition, the terminal provided by the above embodiment and the scanning method embodiment belong to the same concept, and the specific implementation process thereof is described in the method embodiment, which is not described herein again.

Based on the hardware implementation of the program module, in order to implement the method of the embodiment of the present application, the embodiment of the present application further provides a terminal. Fig. 7 is a schematic diagram of a hardware composition structure of a terminal according to an embodiment of the present application, and as shown in fig. 7, the terminal includes:

a communication interface 1 capable of information interaction with other devices such as network devices and the like;

and the processor 2 is connected with the communication interface 1 to realize information interaction with other equipment, and is used for executing the method provided by one or more technical schemes when running a computer program. And the computer program is stored on the memory 3.

Specifically, the communication interface 1 is configured to:

and receiving a downlink signal.

The processor 2 is configured to:

In one embodiment, the frequency domain correlation detection uses an overlap-and-hold method or an overlap-and-add method.

In one embodiment, the processor 2 is further configured to:

and preprocessing the local synchronization sequence.

In one embodiment, the processor 2 performs frequency compensation on the local synchronization sequence based on the subcarrier spacing and the corresponding grid frequency of the downlink signal in the preprocessing.

In one embodiment, the processor 2 performs a low pass filtering process on the local synchronization sequence in the preprocessing.

In one embodiment, the processor 2 additively combines at least two numbered local synchronization sequence lines in the preprocessing.

In practice, of course, the various components in the terminal are coupled together by means of the bus system 4. It will be appreciated that the bus system 4 is used to enable connection communication between these components. The bus system 4 comprises, in addition to a data bus, a power bus, a control bus and a status signal bus. For the sake of clarity, however, the various buses are labeled as bus system 4 in fig. 7.

The memory 3 in the embodiment of the present application is used to store various types of data to support operations in the terminal. Examples of such data include: any computer program for operating on a terminal.

It will be appreciated that the memory can be either volatile memory or nonvolatile memory, and can include both volatile and nonvolatile memory. Among them, the nonvolatile Memory may be a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a magnetic random access Memory (FRAM), a Flash Memory (Flash Memory), a magnetic surface Memory, an optical disk, or a Compact Disc Read-Only Memory (CD-ROM); the magnetic surface storage may be disk storage or tape storage. Volatile Memory can be Random Access Memory (RAM), which acts as external cache Memory. By way of illustration and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Enhanced Synchronous Dynamic Random Access Memory (Enhanced DRAM), Synchronous Dynamic Random Access Memory (SLDRAM), Direct Memory (DRmb Access), and Random Access Memory (DRAM). The memories described in the embodiments of the present application are intended to comprise, without being limited to, these and any other suitable types of memory.

The method disclosed in the embodiments of the present application may be applied to a processor, or may be implemented by a processor. The processor may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The processor described above may be a general purpose processor, a DSP, or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. The processor may implement or perform the methods, steps, and logic blocks disclosed in the embodiments of the present application. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in a storage medium located in a memory where a processor reads the programs in the memory and in combination with its hardware performs the steps of the method as previously described.

When the processor executes the program, corresponding processes in the methods of the embodiments of the present application are implemented, and for brevity, are not described herein again.

In an exemplary embodiment, the present application further provides a storage medium, i.e., a computer storage medium, specifically a computer readable storage medium, for example, including a memory storing a computer program, which is executable by a processor to perform the steps of the foregoing method. The computer readable storage medium may be Memory such as FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface Memory, optical disk, or CD-ROM.

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

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, all functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: a removable storage device, a ROM, a RAM, a magnetic or optical disk, or various other media that can store program code.

Alternatively, the integrated units described above in the present application may be stored in a computer-readable storage medium if they are implemented in the form of software functional modules and sold or used as independent products. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially implemented or portions thereof that contribute to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling an electronic device (which may be a personal computer, a server, or a network device) to execute all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a removable storage device, a ROM, a RAM, a magnetic or optical disk, or various other media that can store program code.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A scanning method, comprising the steps of:

receiving a downlink signal;

2. The method of claim 1,

the specified threshold is derived based on the smallest possible bandwidth determined by the 3GPP specifications.

3. The method of claim 1,

the frequency domain correlation detection uses either an overlap-and-hold method or an overlap-and-add method.

4. The method of claim 1, further comprising the steps of:

and preprocessing the local synchronization sequence.

5. The method of claim 4,

in the preprocessing, the local synchronization sequence is frequency compensated based on the subcarrier interval of the downlink signal and the corresponding grid frequency.

6. The method of claim 4,

in the preprocessing, the local synchronization sequence is low-pass filtered.

7. The method of claim 4,

in the preprocessing, at least two numbered local synchronization sequence lines are additively combined.

8. A terminal, comprising:

a receiving unit, configured to receive a downlink signal;

9. A terminal, comprising: a communication interface, a processor, and a memory for storing a computer program capable of running on the processor;

wherein the processor is configured to execute the steps corresponding to the method according to any one of claims 1 to 7 when the computer program is executed.

10. A storage medium having a computer program stored thereon, the computer program, when being executed by a processor, performing the steps of the method of any one of claims 1 to 7.