LTE (Long Term Evolution) cell searching method and device

Abstract

The invention belongs to the technical field of communication, and provides an LTE (Long Term Evolution) cell searching method and device, and the method comprises the steps: generating a CRS (Cell Reference Signal) sequence according to a PCI (Peripheral Component Interconnect) defined by an LTE communication system; the method comprises the following steps: extracting a time domain signal from a received signal with a time slot length, sampling the time domain signal at equal intervals, and converting the sampled signal into a frequency domain signal; for the CRS sequence corresponding to each PCI, extracting subcarrier data from the frequency domain signal, and performing correlation operation on the subcarrier data and the target CRS sequence to obtain a correlation value of the current PCI; traversing all PCIs to obtain a plurality of correlation values; and determining the maximum value in the plurality of correlation values as a target PCI (Peripheral Component Interconnect), and performing cell search according to the target PCI. According to the method provided by the invention, the cell search process can be completed in a faster and shorter period by using the cell reference signal, and only one time sequence data needs to be stored, so that the cell search overhead is reduced, and the cell search efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular, to an LTE cell search method and apparatus. Background Art

[0002] In an LTE (Long Term Evolution) communication system, if a terminal device accesses the network, it needs to go through processes such as cell search, obtaining system information, and random access in sequence; a UE (User Equipment) not only needs to perform cell search when powered on, but also, in order to support mobility, the UE continuously searches for neighboring cells, acquires synchronization, and estimates the received quality of the signal of the cell, so as to determine whether to perform handover or cell reselection.

[0003] In related technologies, a PCI (Physical-layer Cell Identity) is usually obtained by using a PSS (Primary Synchronization Signal) and an SSS (Secondary Synchronization Signal). However, since the periods of both signals are 5 ms, the cell search process cannot be completed in a shorter time, which is time-consuming as a whole. Moreover, in engineering implementation, data longer than 5 ms needs to be stored, involving a large amount of data, resulting in large cell search overhead and low efficiency. Summary of the Invention

[0004] The present invention provides an LTE cell search method and apparatus, which are used to solve the defects that when the prior art uses a PSS and an SSS to obtain a PCI for cell search, the time consumption is long, and a large amount of data needs to be stored in engineering implementation, resulting in large cell search overhead and low efficiency; the method of the present invention improves the cell search efficiency.

[0005] The present invention provides an LTE cell search method, including: Generating a cell reference signal CRS sequence according to a physical-layer cell identity PCI defined by an LTE (Long Term Evolution) communication system; extracting a time-domain signal from a received signal with a slot length, performing equally-spaced sampling on the time-domain signal, and converting the sampled signal into a frequency-domain signal; wherein, different PCIs correspond to different CRS sequences; For each CRS sequence corresponding to a PCI, extracting subcarrier data from the frequency-domain signal, and performing a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of the current PCI; wherein, the PCI is one of the different PCIs, and the PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequences; Traverse all PCIs to obtain multiple relevant values; determine the maximum value among the multiple relevant values as the target PCI, and perform cell search according to the target PCI.

[0006] According to an LTE cell search method provided by the present invention, the extracting subcarrier data from the frequency-domain signal includes: Extract multiple subcarriers from both end frequency band regions of the frequency-domain signal according to a preset index range; Determine an offset according to the target modulo result corresponding to the current PCI; According to the offset, and taking the modulo corresponding to the target modulo result as the extraction interval, obtain the subcarrier data from the multiple subcarriers.

[0007] According to an LTE cell search method provided by the present invention, the step size of the equally spaced sampling is 16 sampling points, and each sampling includes 2048 consecutive sampling points.

[0008] According to an LTE cell search method provided by the present invention, the performing a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of the current PCI includes: Calculate the signal reception power according to the subcarrier data; Calculate the correlation power of the current PCI according to the target CRS sequence; Determine the correlation value of the current PCI according to the ratio of the correlation power to the signal reception power.

[0009] According to an LTE cell search method provided by the present invention, each CRS sequence includes multiple time slot numbers; The performing cell search according to the target PCI includes: Obtain the time slot numbers corresponding to the target PCI; Calculate the starting position of the system frame according to the time slot numbers corresponding to the target PCI to obtain a downlink synchronization point; Perform a cell search task according to the downlink synchronization point.

[0010] According to an LTE cell search method provided by the present invention, the converting the sampled signal into a frequency-domain signal includes: Perform a fast Fourier transform (FFT) on the sampled signal according to the following formula to obtain the frequency-domain signal: ; where n and k are indices, is the frequency-domain signal, is the sampled signal.

[0011] The present invention also provides an LTE cell search device, comprising: a CRS sequence generation module, configured to generate a cell reference signal CRS sequence according to a physical layer cell identifier PCI defined by a Long Term Evolution (LTE) communication system; extract a time-domain signal from a received signal with a slot length, perform equally-spaced sampling on the time-domain signal, and convert the sampled signal into a frequency-domain signal; wherein different PCIs correspond to different CRS sequences; a calculation module, configured to extract subcarrier data from the frequency-domain signal for each CRS sequence corresponding to a PCI, and perform a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of the current PCI; wherein the PCI is one of the different PCIs, and the PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequences; a cell search module, configured to traverse all PCIs to obtain a plurality of correlation values; determine the maximum value among the plurality of correlation values as a target PCI, and perform cell search according to the target PCI.

[0012] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the LTE cell search method as described in any one of the above is implemented.

[0013] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the LTE cell search method as described in any one of the above is implemented.

[0014] The present invention also provides a computer program product, comprising a computer program, and when the computer program is executed by a processor, the LTE cell search method as described in any one of the above is implemented.

[0015] The LTE cell search method and device provided by the present invention generate a cell reference signal CRS sequence according to a physical layer cell identifier PCI defined by an LTE communication system; intercept a time-domain signal with a slot length from a received signal, perform equally-spaced sampling on the time-domain signal and convert it into a frequency-domain signal; then, for each CRS sequence corresponding to a PCI, extract subcarrier data from the frequency-domain signal and perform a correlation operation with the CRS sequence to obtain a plurality of correlation values corresponding to all PCIs. Finally, determine the maximum value among the plurality of correlation values as a target PCI, and perform cell search according to the target PCI. Using the cell reference signal can complete the cell search process more quickly with a shorter period, and only one-time sequence data needs to be stored, reducing the cell search overhead and improving the cell search efficiency. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is one of the schematic flowcharts of the LTE cell search method provided by the present invention.

[0018] Figure 2 It is the second schematic flowchart of the LTE cell search method provided by the present invention.

[0019] Figure 3 It is the schematic structural diagram of the LTE cell search device provided by the present invention.

[0020] Figure 4 It is the schematic structural diagram of the electronic device provided by the present invention. Detailed implementation manners

[0021] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0022] It should be noted that the main purposes of cell search include: achieving frequency and symbol synchronization with the cell (downlink synchronization); obtaining the system frame number and the starting position; determining the PCI (Physical-layer Cell Identity) of the cell.

[0023] The LTE system defines 504 PCIs (value range 0 - 503), and different PCIs correspond to a specific downlink reference signal sequence. The set of all PCIs is divided into 168 groups (value range 0 - 167), and each group contains 3 cell IDs (value range 0 - 2), as shown in the following formula: ; Two types of signals are defined in the LTE system, namely the Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS). The periods of these two types of signals are 5 ms, and the terminal can complete the cell search process using these two types of signals.

[0024] The following combines Figures 1 - 3 to describe the LTE cell search method and apparatus of the present invention.

[0025] Figure 1 is one of the flow schematic diagrams of the LTE cell search method provided by the present invention. As Figure 1 shown, the method includes the following steps: Step 110: Generate a cell reference signal CRS sequence according to the physical layer cell identifier PCI defined by the Long Term Evolution (LTE) communication system; extract the time-domain signal from the received signal of one time slot length, perform equally spaced sampling on the time-domain signal, and convert the sampled signal into a frequency-domain signal; wherein, different PCIs correspond to different CRS sequences.

[0026] In this step, a cell-specific reference signal CRS (Cell-specific Reference Signal) is defined in the LTE system. The CRS includes OFDM symbols (for example, 0 / 4 / 7 / 11) of each downlink subframe, and the CRS sequence includes multiple PCI values.

[0027] Specifically, according to the 504 physical layer cell identifiers (PCIs) defined by the LTE standard, each PCI corresponds to a unique cell reference signal CRS sequence; the generation of the CRS sequence follows the 3GPP TS 36.211 specification, and the CRS sequence corresponding to each PCI is specifically calculated by the following formula: ; ; wherein, is the cell PCI (value range 0 to 503), is the time slot number (value range 0 to 19), is the OFDM symbol index within the time slot; is the cyclic prefix type (value 0 or 1), is the sequence initial value, is the number of downlink bandwidth RBs (value 100).

[0028] In this embodiment, 504 PCIs correspond to 504 possible CRS sequence configurations, and each time slot number corresponds to 20 groups of sequence variants.

[0029] In this embodiment, by arbitrarily intercepting the received signal of one time slot and extracting the time-domain signal therefrom; wherein, the length of one time slot is 0.5 ms, and the received signal includes 15360 sampling points.

[0030] In this embodiment, the equidistant sampling step size can be set according to user requirements. For example, the step size of equidistant sampling is 16 sampling points, and each sampling includes 2048 consecutive sampling points, which can cover the complete period of the OFDM symbol.

[0031] In this embodiment, after obtaining the sampling signal, perform time-frequency conversion on the sampling signal to convert the time-domain signal into a frequency-domain signal. The two end frequency band regions of the frequency-domain signal contain multiple valid subcarriers.

[0032] Step 120: For each CRS sequence corresponding to a PCI, extract subcarrier data from the frequency-domain signal, and perform a correlation operation between the subcarrier data and the target CRS sequence to obtain the correlation value of the current PCI; where PCI is one of different PCIs, and PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequence.

[0033] In this step, a subcarrier set can be extracted from the frequency-domain signal according to a preset index, and then valid subcarriers, that is, subcarrier data, can be extracted from the subcarrier set according to a preset equidistant extraction method.

[0034] In this step, the target CRS sequence can be the current CRS sequence or a part. For example, the target CRS sequence is a segment intercepted from the current CRS sequence.

[0035] In this embodiment, the association between PCI and subcarriers means that when extracting the subcarrier data corresponding to the current PCI from the frequency-domain signal, the subcarrier interception position is determined based on the starting offset and extraction interval during extraction, and the starting offset is determined by the modulo result of the current PCI.

[0036] In this embodiment, the correlation operation is used to compare the similarity between the CRS sequence corresponding to the current PCI and the received signal, and then obtain the correlation value (quantized value) corresponding to a time slot number of the current PCI for subsequent determination of the maximum value of the correlation value.

[0037] Step 130: Traverse all PCIs to obtain multiple correlation values; determine the maximum value among the multiple correlation values as the target PCI, and perform cell search according to the target PCI.

[0038] In this step, after obtaining the correlation values between the CRS sequence corresponding to each PCI and the subcarriers of the received signal through step 120, 504 correlation values can be obtained.

[0039] In this embodiment, select the PCI corresponding to the maximum correlation value among the 504 correlation values as the target PCI. After determining the time slot number corresponding to the target PCI, perform the cell search task according to the downlink synchronization point corresponding to the time slot number.

[0040] The LTE cell search method provided by the embodiment of the present invention generates a cell reference signal (CRS) sequence through a physical layer cell identifier (PCI) defined by an LTE communication system; intercepts a time-domain signal with a slot length from the received signal, and performs equally-spaced sampling on the time-domain signal to convert it into a frequency-domain signal; then, for each CRS sequence corresponding to a PCI, extracts subcarrier data from the frequency-domain signal and performs a correlation operation with the CRS sequence to obtain multiple correlation values corresponding to all PCIs. Finally, determines the maximum value among the multiple correlation values as the target PCI, and performs cell search according to the target PCI. By using the cell reference signal, the cell search process can be completed more quickly with a shorter period, and only one-time sequence data needs to be stored, reducing the cell search overhead and improving the cell search efficiency.

[0041] In some embodiments, extracting subcarrier data from the frequency-domain signal includes: extracting a plurality of subcarriers from the two end frequency band regions of the frequency-domain signal according to a preset index range; determining an offset according to the target modulo result corresponding to the current PCI; and obtaining subcarrier data from the plurality of subcarriers according to the offset and using the modulo corresponding to the target modulo result as the extraction interval.

[0042] In this embodiment, the preset index range may include one or more; for example, the preset index range includes a low-frequency band extraction index range for extracting 1-36 subcarriers in the low frequency; the preset index range also includes a high-frequency band extraction index range for extracting 2013-2048 subcarriers in the high frequency. According to the above two index ranges, a total of 72 points can be obtained.

[0043] In this embodiment, by calculating the modulo of the PCI by 6, an offset of 0-5 is obtained, and 504 PCIs are mapped to 6 frequency-domain modes.

[0044] For example, when PCI = 503, 503%6 = 5, the offset = 5, and extraction starts from the 6th subcarrier.

[0045] In this embodiment, the frequency-domain signal includes 2048-point data. By setting the index range to 1~36 and 2013~2048, a total of 72 data can be obtained. Then, according to the result of the PCI modulo 6 (0, 1, 2, 3, 4, 5) as the offset, 12 data are taken out; for example, when PCI = 8, the result of modulo 6 is 2. Among the 72-point data, starting from the 3rd and taking data at an interval of 6 data (i.e., indexes 3, 9, 15,..., 69), the corresponding subcarrier data is obtained.

[0046] The LTE cell search method provided by the embodiments of the present invention extracts multiple subcarriers from the two end frequency bands of the frequency domain signal through a preset index range; determines an offset according to the target modulo result corresponding to the current PCI; and obtains subcarrier data from the multiple subcarriers according to the offset and with the modulo corresponding to the target modulo result as the extraction interval, realizing three-level optimization of precise focusing in the frequency domain, compression by the modulo-6 rule, and noise reduction by interval extraction, ensuring that the PCI detection speed enters the sub-millisecond level and further improving the cell search efficiency.

[0047] In some embodiments, performing a correlation operation on the subcarrier data and the target CRS sequence to obtain the correlation value of the current PCI includes: calculating the signal reception power according to the subcarrier data; calculating the correlation power of the current PCI according to the target CRS sequence; and determining the correlation value of the current PCI according to the ratio of the correlation power to the signal reception power.

[0048] In this embodiment, performing a correlation operation on the subcarrier data and the target CRS sequence is specifically implemented through the following steps: (1) Calculate the signal reception power through the following formula : ; Wherein, real is to take the real part of the complex number, imag is to take the imaginary part of the complex number,.^2 is to calculate the square values of the 12 numbers in the vector respectively, sum is to sum up the 12 numbers; RxCrs is the subcarrier data.

[0049] (2) Calculate the correlation power of the current PCI through the following formula : ; ; Wherein, is the target CRS sequence, is a temporary variable in the calculation process for saving the result; conj is to take the conjugate of the complex number.

[0050] (3) Calculate the correlation value of the current PCI through the following formula : .

[0051] The LTE cell search method provided by the embodiments of the present invention calculates the signal reception power through subcarrier data; calculates the relevant power of the current PCI according to the target CRS sequence; determines the relevant value of the current PCI according to the ratio of the relevant power to the signal reception power, and can quickly determine the signal reception ability of each PCI by comparing the correlation between each PCI corresponding sequence and the received signal, so as to quickly locate the target PCI cell.

[0052] In some embodiments, each CRS sequence includes a plurality of time slot numbers; the cell search according to the target PCI includes: obtaining the time slot numbers corresponding to the target PCI; calculating the starting position of the system frame according to the time slot numbers corresponding to the target PCI to obtain the downlink synchronization point; and performing the cell search task according to the downlink synchronization point.

[0053] In this embodiment, the target PCI and the current time slot number SlotNo can be obtained according to the relevant value of the maximum value, and then the starting position of the system frame can be calculated according to the time slot number SlotNo, that is, the downlink synchronization point is found, and then the cell scan is performed using the downlink synchronization point.

[0054] Specifically, the time slot number (SlotNo, with a value range of 0-19) is parsed through the CRS sequence parameters and stored in a binding manner with the PCI. For example, the above calculation c init in the formula can be directly mapped to SlotNo.

[0055] In this embodiment, according to the LTE frame structure (1 frame = 10 ms = 20 time slots), the starting position FrameStart of the system frame is calculated by the following formula: FrameStart = SlotNo × 0.5 ms + TimingOffset; where TimingOffset is the time fine-tuning amount, which is determined by the relevant peak position (with an accuracy of ±16 sampling points, approximately 52 ns); In this embodiment, the cell search is started at the FrameStart position to align with the 5 ms half-frame boundary.

[0056] The LTE cell search method provided by the embodiments of the present invention obtains the downlink synchronization point by calculating the starting position of the system frame according to the time slot numbers corresponding to the target PCI; and performs the cell search task according to the downlink synchronization point, skipping the PSS / SSS detection link, effectively shortening the cell search time.

[0057] In some embodiments, converting the sampled signal into a frequency-domain signal includes: performing a fast Fourier transform (FFT) on the sampled signal according to the following formula to obtain the frequency-domain signal: ; Among them, n and k are indexes, is a frequency-domain signal, is a sampling signal.

[0058] In this embodiment, a received signal of any intercepted time slot (the time slot length is 0.5 ms and the data length is 15360) is taken; one OFDM symbol's data is taken every 16 points, that is, the time-domain signal (denoted as RxSigTime, with a length of 2048). For example, the above interval sampling includes: the first time taking the data from 1 to 2048, the second time taking the data of 16+(1:2048), and so on. The nth time takes the data of 16 (n - 1)+(1:2048).

[0059] In this embodiment, the time-domain signal is subjected to FFT conversion according to the above formula to obtain a frequency-domain signal; among them, both n and k are indexes, and the corresponding index value ranges are from 0 to 2047.

[0060] The LTE cell search method provided by the embodiment of the present invention converts the sampling signal into a frequency-domain signal through FFT transformation, providing data support for subsequent extraction of frequency-domain carrier data.

[0061] Figure 2 is the second flow chart of the LTE cell search method provided by the present invention. In Figure 2 the shown embodiment, the LTE cell search method includes the following steps: (1) Generate a local CES sequence, extract the time-domain signal from the received signal, and convert the time-domain signal into a frequency-domain signal; (2) Extract the middle 6RB data from the frequency-domain signal and the local CES sequence respectively; (3) Perform a correlation operation according to the two extracted 6RB data to obtain the corresponding correlation value for each local CES sequence; (4) Obtain the required PCI and the corresponding time slot number according to the maximum value of the correlation value; (5) Obtain the frame start position according to the time slot number, thereby realizing cell search.

[0062] Next, the LTE cell search device provided by the present invention will be described. The LTE cell search device described below can be correspondingly referred to the LTE cell search method described above.

[0063] Figure 3 is the structural diagram of the LTE cell search device provided by the present invention. As Figure 3 shown, the LTE cell search device includes: a CRS sequence generation module 310, a calculation module 320, and a cell search module 330.

[0064] The CRS sequence generation module 310 is configured to generate a cell reference signal (CRS) sequence according to a physical layer cell identifier (PCI) defined by a Long Term Evolution (LTE) communication system; intercept a time-domain signal of a time slot length from the received signal, perform equally-spaced sampling on the time-domain signal, and convert the sampled signal into a frequency-domain signal; wherein, different PCIs correspond to different CRS sequences, and each CRS sequence includes multiple time slot numbers. The calculation module 320 is configured to extract subcarrier data from the frequency-domain signal for each CRS sequence corresponding to a PCI, and perform a correlation operation on the subcarrier data and the CRS sequence to obtain a correlation value of the current PCI; wherein, the PCI is one of different PCIs, and the PCI is associated with the subcarrier data. The cell search module 330 is configured to traverse all PCIs to obtain multiple correlation values; determine the maximum value among the multiple correlation values as the target PCI, and perform cell search according to the target PCI.

[0065] The LTE cell search device provided by the embodiment of the present invention generates a cell reference signal (CRS) sequence according to a physical layer cell identifier (PCI) defined by an LTE communication system; intercepts a time-domain signal of a time slot length from the received signal, performs equally-spaced sampling on the time-domain signal and converts it into a frequency-domain signal; then extracts subcarrier data from the frequency-domain signal for each CRS sequence corresponding to a PCI and performs a correlation operation on the subcarrier data and the CRS sequence to obtain multiple correlation values corresponding to all PCIs, and finally determines the maximum value among the multiple correlation values as the target PCI, and performs cell search according to the target PCI. By using the cell reference signal, the cell search process can be completed more quickly with a shorter period, and only one-time sequence data needs to be stored, reducing the cell search overhead and improving the cell search efficiency.

[0066] Figure 4 An entity structure diagram of an electronic device is illustrated, as Figure 4As shown in the figure, the electronic device may include: a processor 410, a communications interface 420, a memory 430, and a communication bus 440. Among them, the processor 410, the communications interface 420, and the memory 430 complete communication with each other through the communication bus 440. The processor 410 may call logic instructions in the memory 430 to execute the LTE cell search method, which includes: generating a cell reference signal CRS sequence according to the physical layer cell identifier PCI defined by the Long-Term Evolution (LTE) communication system; extracting a time-domain signal from the received signal with a slot length, equally spacing the samples of the time-domain signal, and converting the sampled signal into a frequency-domain signal; where different PCIs correspond to different CRS sequences; for the CRS sequence corresponding to each PCI, extracting subcarrier data from the frequency-domain signal, and performing a correlation operation on the subcarrier data and the target CRS sequence to obtain the correlation value of the current PCI; where PCI is one of different PCIs, and PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequences; traversing all PCIs to obtain a plurality of correlation values; determining the maximum value among the plurality of correlation values as the target PCI, and performing cell search according to the target PCI.

[0067] In addition, when the logic instructions in the above-mentioned memory 430 can be implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc that can store program codes.

[0068] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the LTE cell search method provided by each of the above methods. The method includes: generating a cell reference signal CRS sequence according to the physical layer cell identifier PCI defined by the Long-Term Evolution (LTE) communication system; extracting a time-domain signal from a received signal of one time slot length, performing equally-spaced sampling on the time-domain signal, and converting the sampled signal into a frequency-domain signal; wherein, different PCIs correspond to different CRS sequences; for each CRS sequence corresponding to a PCI, extracting subcarrier data from the frequency-domain signal, and performing a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of the current PCI; wherein, the PCI is one of different PCIs, and the PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequences; traversing all PCIs to obtain a plurality of correlation values; determining the maximum value among the plurality of correlation values as the target PCI, and performing cell search according to the target PCI.

[0069] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is configured to execute the LTE cell search method provided by each of the above methods. The method includes: generating a cell reference signal CRS sequence according to the physical layer cell identifier PCI defined by the Long-Term Evolution (LTE) communication system; extracting a time-domain signal from a received signal of one time slot length, performing equally-spaced sampling on the time-domain signal, and converting the sampled signal into a frequency-domain signal; wherein, different PCIs correspond to different CRS sequences; for each CRS sequence corresponding to a PCI, extracting subcarrier data from the frequency-domain signal, and performing a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of the current PCI; wherein, the PCI is one of different PCIs, and the PCI is associated with the subcarrier data; the target CRS sequence belongs to the CRS sequences; traversing all PCIs to obtain a plurality of correlation values; determining the maximum value among the plurality of correlation values as the target PCI, and performing cell search according to the target PCI.

[0070] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0071] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A LTE cell search method, characterized in that: include: Generate a cell reference signal CRS sequence according to the physical layer cell identifier PCI defined in the long term evolution LTE communication system; extract a time domain signal from a received signal of a time slot length, sample the time domain signal at equal intervals, and convert the sampled signal into a frequency domain signal; wherein different PCIs correspond to different CRS sequences; For each CRS sequence corresponding to the PCI, extract subcarrier data from the frequency domain signal, and perform a correlation operation on the subcarrier data and the target CRS sequence to obtain a correlation value of the current PCI; wherein the PCI is one of the different PCIs, and the PCI is associated with the subcarrier data; and the target CRS sequence belongs to the CRS sequence; All PCIs are traversed to obtain multiple correlation values; a maximum value among the multiple correlation values ​​is determined as a target PCI, and a cell search is performed according to the target PCI.

2. The LTE cell search method according to claim 1, characterized in that: The extracting subcarrier data from the frequency domain signal comprises: Extracting a plurality of subcarriers from the frequency band regions at both ends of the frequency domain signal according to a preset index range; Determine an offset according to a target modulo result corresponding to the current PCI; The subcarrier data is obtained from the multiple subcarriers according to the offset and with the modulus corresponding to the target modulo result as an extraction interval.

3. The LTE cell search method according to claim 1, characterized in that: The step length of the equally spaced sampling is 16 sampling points, and each sampling includes 2048 continuous sampling points.

4. The LTE cell search method according to claim 1, characterized in that: The correlating operation of the subcarrier data with the target CRS sequence to obtain the correlation value of the current PCI includes: Calculate signal receiving power according to the subcarrier data; Calculate the relevant power of the current PCI according to the target CRS sequence; The correlation value of the current PCI is determined according to the ratio of the correlation power to the signal reception power.

5. The LTE cell search method according to claim 1, characterized in that: Each CRS sequence includes multiple time slot numbers; The performing a cell search according to the target PCI includes: Obtain the time slot number corresponding to the target PCI; Calculate the starting position of the system frame according to the time slot number corresponding to the target PCI to obtain a downlink synchronization point; A cell search task is performed according to the downlink synchronization point.

6. The LTE cell search method according to claim 1, characterized in that: The converting the sampled signal into a frequency domain signal comprises: Perform a fast Fourier transform (FFT) on the sampled signal according to the following formula to obtain the frequency domain signal: ； in, n and k is the index, is the frequency domain signal, is the sampling signal.

7. An LTE cell search device, characterized in that: include: A CRS sequence generation module is used to generate a cell reference signal CRS sequence according to a physical layer cell identifier PCI defined in a long-term evolution LTE communication system; extract a time domain signal from a received signal of a time slot length, perform equal-interval sampling on the time domain signal, and convert the sampled signal into a frequency domain signal; wherein different PCIs correspond to different CRS sequences; A calculation module, configured to extract subcarrier data from the frequency domain signal for a CRS sequence corresponding to each PCI, and perform a correlation operation on the subcarrier data and a target CRS sequence to obtain a correlation value of a current PCI; wherein the PCI is one of the different PCIs, and the PCI is associated with the subcarrier data; and the target CRS sequence belongs to the CRS sequence; The cell search module is used to traverse all PCIs to obtain multiple related values; determine the maximum value of the multiple related values ​​as the target PCI, and perform cell search according to the target PCI.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the LTE cell search method according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the LTE cell search method according to any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the LTE cell search method according to any one of claims 1 to 6 is implemented.

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