Random access processing method and device based on frequency offset correction

Abstract

The present application discloses a random access processing method and device based on frequency offset correction. The random access processing method based on frequency offset correction includes: obtaining a received signal from a second node; executing a detection procedure, including: performing correlation calculation on the received signal and a local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence; when a larger peak is identified, estimating the round-trip transmission delay value according to the position of the larger peak; when two larger peaks are identified, estimating the frequency offset of the received signal based on the two larger peaks, and correcting the frequency offset of the received signal according to the frequency offset, and re-executing the detection procedure based on the received signal after the frequency offset correction; feeding back the round-trip transmission delay value to the second node, so that the second node adjusts the timing based on the round-trip transmission delay value, and continues the subsequent random access process. Therefore, the detection probability can be improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a random access processing method and device based on frequency offset correction. Background Art

[0002] Taking the Long Term Evolution (LTE) communication system as an example, when a terminal accesses, it sends a random access preamble (PRACH preamble) to the base station. After the base station detects the random access preamble, it sends a random access channel response (RAR) to the terminal.

[0003] When the terminal moves at a speed relative to the base station, both the downlink and uplink of wireless communication will generate Doppler frequency shift. The Doppler frequency shift calculation formula is as follows:

[0004] Among them, f d is the Doppler frequency shift, f c is the carrier frequency, v is the moving speed of the mobile station, and c is the speed of light. According to the calculation formula, for the same carrier frequency, the faster the terminal moves relative to the base station, the greater the Doppler frequency deviation generated by the downlink and uplink of the wireless communication (in addition, the initial carrier frequency deviation of the terminal relative to the base station may also be relatively large).

[0005] When the total frequency deviation of the carrier frequency deviation and the Doppler frequency deviation is larger, the probability of the base station detecting the random access preamble code will be greatly reduced. When the total frequency deviation exceeds a certain range, the base station may not detect the random access preamble code, or even detect an erroneous random access preamble code.

[0006] Therefore, in the application scenario of high-speed moving terminals or terminals with large total frequency deviation, there has long been a problem in the prior art that the base station has a poor detection probability of detecting the random access preamble code sent by the terminal, making it impossible for the terminal to access the network normally. Summary of the invention

[0007] The embodiments of the present application provide a random access processing method and device based on frequency offset correction, which solves the problem in the prior art that, in the application scenario of a high-speed moving terminal or a terminal with a large total frequency offset, the base station has long had a poor detection probability of detecting a random access preamble code sent by the terminal, making it impossible for the terminal to access the network normally.

[0008] In order to solve the above technical problems, this application is implemented as follows:

[0009] In one embodiment, a random access processing method based on frequency offset correction is provided, which is applied to a first node. The random access processing method based on frequency offset correction includes the following steps: obtaining a received signal from a second node; executing a detection procedure, the detection procedure including: performing correlation calculation on the received signal and a local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence; when a larger peak is identified, estimating a round trip delay (RTD) value according to the position of the larger peak; when two larger peaks are identified, estimating the frequency offset of the received signal based on the two larger peaks, and performing frequency offset correction on the received signal according to the frequency offset, and re-executing the detection procedure based on the received signal after the frequency offset correction; feeding back the round trip delay value to the second node, so that the second node adjusts the timing based on the round trip delay value, and continues the subsequent random access process.

[0010] In one embodiment, a random access processing device based on frequency offset correction is provided, which is arranged in a first node and includes: a transmission and reception module, a processing module, an estimation module and a frequency offset correction module, the processing module is connected to the transmission and reception module, the estimation module is connected to the processing module and the transmission and reception module, and the frequency offset correction module is connected to the processing module. Among them, the transmission and reception module is used to receive the signal from the second node, and to feed back the round-trip transmission delay value to the second node, so that the second node adjusts the timing based on the round-trip transmission delay value and continues the subsequent random access process; the processing module is used to execute the detection procedure, and the detection procedure includes: performing correlation calculation on the received signal and the local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence; the estimation module is used to estimate the round-trip transmission delay value according to the position of the larger peak when the processing module identifies the existence of a larger peak based on the result of the correlation calculation between the received signal and the local sequence; the frequency deviation correction module is used to estimate the frequency deviation of the received signal based on the two larger peaks when the processing module identifies the existence of two larger peaks, and perform frequency deviation correction on the received signal according to the frequency deviation, and transmit the received signal after the frequency deviation correction to the processing module, so that the processing module re-executes the detection procedure based on the received signal after the frequency deviation correction.

[0011] In an embodiment of the present application, by performing correlation calculation on the received signal and the local sequence signal when detecting the random access preamble code, when it is identified that there are two larger peaks in the result of the correlation calculation and the power difference between the two larger peaks does not exceed the threshold value (that is, it is identified that a frequency deviation occurs), the frequency deviation of the received signal is estimated based on the two larger peaks, and the frequency deviation of the received signal is corrected according to the frequency deviation, and the detection procedure is re-executed based on the received signal after the frequency deviation correction, thereby improving the detection probability and being able to obtain a more accurate round-trip transmission delay value between the first node and the second node. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0013] Figure 1 is a block diagram of a random access processing device based on frequency offset correction according to an embodiment of the present invention;

[0014] Figure 2 A schematic diagram of an embodiment of a power delay spectrum according to the present application;

[0015] Figure 3 is a schematic diagram of another embodiment of a power delay spectrum according to the present application; and

[0016] Figure 4 The present invention is a method flow chart of an embodiment of a random access processing method based on frequency offset correction according to the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] See also Figure 1 , Figure 1 The figure is a block diagram of a random access processing device based on frequency offset correction according to an embodiment of the present invention.

[0019] like Figure 1As shown, a random access processing device 100 based on frequency offset correction can be set in a first node, and includes: a transceiver module 110, a processing module 120, an estimation module 130 and a frequency offset correction module 140, wherein the processing module 120 is connected to the transceiver module 110, the estimation module 130 is connected to the processing module 120 and the transceiver module 110, and the frequency offset correction module 140 is connected to the processing module 120. The processing module 120, the estimation module 130 and the frequency offset correction module 140 can be generated by one or more processors executing a specific program loaded into one or more storage modules, or included in one or more processors, wherein the processor can be a processing unit, a microprocessor or any suitable processing element; the storage module can include any type of volatile memory and / or non-volatile memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), flash memory (Flash), read-only memory (ROM), etc.

[0020] The transceiver module 110 can be used to receive signals from the second node and feed back the round-trip transmission delay value to the second node, so that the second node can adjust the timing based on the round-trip transmission delay value and continue the subsequent random access process. The first node and the second node can be a central node and a non-central node (i.e., a node to be accessed), respectively, or a base station and a terminal (i.e., the first node is a base station and the second node is a terminal), or both can be terminals (i.e., the second node is a terminal to be accessed).

[0021] The random access preamble of the received signal is generated by the second node according to the root sequence number. The formula for generating the ZC root sequence is: x u (n) is the ZC root sequence, u is the root sequence number, N ZC is the length of the ZC root sequence, 0≤n≤N ZC -1, n is a constant. Each root sequence corresponds to a reverse sequence number d u (The following is the d of the ZC root sequence u value), d u To satisfy u )mod N ZC = 1. For example, there are two lengths of ZC root sequence defined in the LTE protocol: N ZC =839 and N ZC =139, when N ZC =839, the physical random access channel (PRACH) subcarrier spacing is 1.25khz. At this time, when the root sequence number (i.e., u) is 12, the reverse sequence number (i.e., d u) is 70; when the root sequence number (i.e. u) is 793, the reverse sequence number (i.e. d u ) is 383.

[0022] In one embodiment, the second node also transmits a transmission sequence obtained by modulating the synchronization information sequence to the first node (i.e., the transmission and reception module 110 of the random access processing device 100 based on frequency offset correction), wherein the transmission sequence is called a synchronization sequence in the second node and a local sequence in the first node.

[0023] The processing module 120 may be used to execute a detection procedure, which includes: performing correlation calculation on the received signal and the local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence.

[0024] In one embodiment, the processing module 120 may perform frequency correction and downsampling on the received signal, and then perform a Fast Fourier Transform (FFT) to extract a frequency domain signal having the length of the ZC root sequence (e.g., N ZC =839, extract the frequency domain signal at 839 points); then perform correlation calculation on the frequency domain signal having the length of the ZC root sequence and the local sequence.

[0025] In one embodiment, the processing module 120 performs correlation calculation on the received signal and the local sequence to obtain a power delay spectrum, and the processing module 120 further identifies the existence of one or two large peaks based on the power delay spectrum. Figure 2 and Figure 3 , Figure 2 Schematic diagram of an embodiment of a power delay spectrum according to the present application. Figure 3 FIG. 1 is a schematic diagram of another embodiment of a power delay spectrum according to the present application, wherein: Figure 2 and Figure 3 All in N ZC =893 and the PRACH subcarrier spacing is 1.25 kHz, the horizontal axis of the power delay spectrum is the delay value (in sampling intervals), and the vertical axis is the power (logarithmic value in dB); Figure 2 There is only one large peak at position 177 in the power delay spectrum; Figure 3 In the power delay spectrum, there is a large peak at the position of 177 and 247 respectively (that is, two large peaks appear in the power delay spectrum), and the distance between the two large peaks is d u (ie d u =70), it should be noted that Figure 3 This is the power delay spectrum when the root sequence number (i.e., u) is 12.

[0026] In one embodiment, the processing module 120 can identify the existence of the one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence, including: the processing module 120 can obtain multiple peaks based on the result of the correlation calculation between the received signal and the local sequence (that is, there are multiple peaks in the power delay spectrum); the processing module 120 can select the first N larger peaks based on the multiple peaks, wherein N is a positive integer greater than or equal to 2; the processing module 120 can determine the first N larger peaks that are separated by a distance of d. u The two peaks (i.e., the positions of the two peaks are d apart) u ) exceeds the threshold value, wherein the d u d is the root sequence of ZC u when the processing module 120 determines that the power difference exceeds the threshold value, it identifies the presence of the one larger peak value; when the processing module 120 determines that the power difference does not exceed the threshold value, it identifies the presence of the two larger peak values.

[0027] In one embodiment, the processing module 120 can identify the existence of the one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence, including: the processing module 120 can obtain multiple peaks based on the result of the correlation calculation between the received signal and the local sequence (that is, there are multiple peaks in the power delay spectrum); the processing module 120 can select two largest peaks based on the multiple peaks (that is, the two peaks with the highest power in the power delay spectrum), and determine whether the power difference between the two largest peaks exceeds a threshold value; when the processing module 120 determines that the power difference exceeds the threshold value, it identifies the existence of the one larger peak; when the processing module 120 determines that the power difference does not exceed the threshold value, it identifies the existence of the two larger peaks.

[0028] The estimation module 130 can be used to estimate the round-trip transmission delay value according to the position of the large peak when the processing module 120 identifies the existence of a large peak based on the result of the correlation calculation performed on the received signal and the local sequence. Since the processing module 120 identifies the existence of a large peak according to the power delay spectrum, indicating that the downlink and uplink of the wireless communication do not generate a large frequency deviation (that is, there is no frequency deviation or the frequency deviation is very small between the first node and the second node), the estimation module 130 can directly estimate the round-trip transmission delay value according to the position of the large peak in the power delay spectrum.

[0029] The frequency offset correction module 140 can be used to estimate the frequency offset of the received signal based on the two larger peaks when the processing module 120 identifies the existence of two larger peaks, and perform frequency offset correction on the received signal according to the frequency offset, and transmit the received signal after the frequency offset correction to the processing module 120, so that the processing module 120 re-executes the detection procedure based on the received signal after the frequency offset correction. Since the processing module 120 identifies the existence of two larger peaks according to the power delay spectrum, indicating that the downlink and uplink of the wireless communication have a large frequency offset, the frequency offset correction module 140 can estimate the frequency offset of the received signal based on the two larger peaks, and perform frequency offset correction on the received signal according to the frequency offset.

[0030] In one embodiment, the frequency offset correction module 140 may estimate the frequency offset of the received signal based on the power difference between the two larger peaks and an integer subcarrier frequency spacing of a physical random access channel (PRACH).

[0031] In one embodiment, if the processing module 120 re-executes the detection procedure based on the received signal after frequency offset correction, and the result of the correlation calculation still identifies the existence of two larger peaks (which represents the opposite of the previous frequency offset correction), the frequency offset correction module 140 inverts the frequency offset and performs frequency offset soft calibration and the detection procedure on the received signal from the second node, so that the result of the subsequent execution of the detection procedure is to identify the existence of a larger peak.

[0032] After receiving the round-trip transmission delay value, the second node may adjust the timing based on the round-trip transmission delay value and continue with the subsequent random access process. The subsequent random access process may include: the second node sends a first message to the first node at the adjusted timing, so that the first node demodulates the first message, and accesses the second node to a physical random access channel.

[0033] Therefore, the random access processing device 100 based on frequency offset correction can perform correlation calculation on the received signal and the local sequence signal when detecting the random access preamble code. When it is identified that there are two larger peaks in the result of the correlation calculation and the power difference between the two larger peaks does not exceed the threshold value (that is, the frequency offset is identified), the frequency offset of the received signal is estimated based on the two larger peaks, and the frequency offset of the received signal is corrected according to the frequency offset, and the detection procedure is re-executed based on the received signal after the frequency offset correction, thereby improving the detection probability and obtaining a more accurate round-trip transmission delay value between the second node and the first node.

[0034] See also Figure 4, which is a method flow chart of an embodiment of a random access processing method based on frequency offset correction according to the present application; the random access processing method based on frequency offset correction can be applied to the first node. As shown in the figure, the random access processing method based on frequency offset correction can include the following steps: obtaining a received signal from the second node (step S210); executing a detection procedure, the detection procedure including: performing correlation calculation on the received signal and the local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence (step S220); when a larger peak is identified, estimating the round-trip transmission delay value according to the position of the larger peak (step S230); when two larger peaks are identified, estimating the frequency offset of the received signal based on the two larger peaks, and performing frequency offset correction on the received signal according to the frequency offset, and re-executing the detection procedure based on the received signal after the frequency offset correction (step S240); feeding back the round-trip transmission delay value to the second node, so that the second node adjusts the timing based on the round-trip transmission delay value, and continues the subsequent random access process (step S250).

[0035] In one embodiment, the identification of the existence of one or two larger peaks based on the result of the correlation calculation performed on the received signal and the local sequence in step S220 may include: obtaining multiple peaks based on the result of the correlation calculation performed on the received signal and the local sequence; selecting the first N larger peaks based on the multiple peaks, wherein N is a positive integer greater than or equal to 2; and determining the first N larger peaks that are separated by a distance of d. u Whether the power difference between the two peaks exceeds the threshold value, wherein the d u d is the root sequence of ZC u value; when it is determined that the power difference exceeds the threshold value, it is identified that there is the one larger peak value; when it is determined that the power difference does not exceed the threshold value, it is identified that there are the two larger peak values.

[0036] In one embodiment, the identification of the existence of one or two larger peaks based on the result of the correlation calculation performed on the received signal and the local sequence in step S220 may include: obtaining multiple peaks based on the result of the correlation calculation performed on the received signal and the local sequence; selecting two largest peaks based on the multiple peaks, and determining whether the power difference between the two largest peaks exceeds a threshold value; when it is determined that the power difference exceeds the threshold value, identifying the existence of the one larger peak; when it is determined that the power difference does not exceed the threshold value, identifying the existence of the two larger peaks.

[0037] In one embodiment, the re-execution of the detection procedure based on the received signal after frequency offset correction in step S240 includes: if the result of the correlation calculation still identifies the existence of two larger peaks during the re-execution of the detection procedure, inverting the frequency offset and performing frequency offset soft calibration and the detection procedure on the received signal from the second node. The estimation of the frequency offset of the received signal based on the two larger peaks may include: estimating the frequency offset of the received signal based on the power difference between the two larger peaks and the integer subcarrier frequency spacing of the physical random access channel.

[0038] In summary, the present application provides a random access processing method and device based on frequency offset correction. When detecting the random access preamble code, the received signal is correlated with the local sequence signal. When two larger peaks are identified in the result of the correlation calculation and the power difference between the two larger peaks does not exceed the threshold value (that is, the frequency offset is identified), the frequency offset of the received signal is estimated based on the two larger peaks, and the frequency offset of the received signal is corrected according to the frequency offset, and the detection procedure is re-executed based on the received signal after the frequency offset correction, thereby improving the detection probability and obtaining a more accurate round-trip transmission delay value between the first node and the second node.

[0039] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0040] The words "first", "second", "third", etc. used in this article are used to modify the components in the claims and are not used to indicate a priority order, a prior relationship, or that one component precedes another, or a temporal order in executing method steps. They are only used to distinguish components with the same name.

[0041] It should be understood that when a component is described as being "connected" or "coupled" to another component, it may be directly connected or coupled to the other component, and there may be intermediate components. Conversely, when a component is described as being "directly connected" or "directly coupled" to another component, there are no intermediate components. In addition, unless otherwise specified in the specification, any singular term also includes the meaning of the plural.

[0042] All or part of the steps in the method described in the present application can be implemented by a computer program, such as an operating system of a computer, a driver for specific hardware in a computer, or a software program. In addition, it can also be implemented in other types of programs as shown above. A person with common knowledge in the art can write the method of the embodiment of the present application into a computer program, which is not described for simplicity. The computer program implemented according to the method of the embodiment of the present application can be stored in a suitable computer-readable medium, such as a DVD, CD-ROM, USB, hard disk, or can be placed in a network server that can be accessed through a network (e.g., the Internet, or other suitable carriers).

[0043] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A random access processing method based on frequency offset correction, applied to a first node, characterized in that: The following steps are involved: obtaining a received signal from a second node; Executing a detection procedure, the detection procedure comprising: performing correlation calculation on the received signal and the local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence; When the existence of the one relatively large peak is identified, a round-trip transmission delay value is estimated according to the position of the one relatively large peak; When the two larger peaks are identified, the frequency deviation of the received signal is estimated based on the two larger peaks, the frequency deviation of the received signal is corrected according to the frequency deviation, and the detection procedure is re-executed based on the received signal after the frequency deviation correction; Feedback the round-trip transmission delay value to the second node, so that the second node adjusts the timing based on the round-trip transmission delay value and continues the subsequent random access process; Wherein, re-executing the detection procedure based on the received signal after frequency offset correction includes: If the result of the correlation calculation still identifies the existence of two larger peaks during the re-execution of the detection procedure, the frequency offset is inverted and a frequency offset soft calibration and the detection procedure are performed on the received signal from the second node.

2. The random access processing method based on frequency offset correction according to claim 1, characterized in that: The identifying that there are one or two large peaks as a result of performing the correlation calculation based on the received signal and the local sequence comprises: Obtaining a plurality of peaks based on the result of performing the correlation calculation between the received signal and the local sequence; Selecting the first N larger peaks based on the multiple peaks, wherein N is a positive integer greater than or equal to 2; Determine the distance between the first N larger peaks as d u Whether the power difference between the two peaks exceeds the threshold value, wherein the d u is the d of the Zaddoff-Chu (ZC) root sequence u value; When it is determined that the power difference exceeds the threshold value, identifying the presence of the larger peak value; When it is determined that the power difference does not exceed the threshold value, it is recognized that the two larger peaks exist.

3. The random access processing method based on frequency offset correction according to claim 1, characterized in that: The identifying that there are one or two large peaks as a result of performing the correlation calculation based on the received signal and the local sequence comprises: Obtaining multiple peaks based on the result of performing the correlation calculation on the received signal and the local sequence; Selecting two largest peaks based on the multiple peaks, and determining whether a power difference between the two largest peaks exceeds a threshold value; When the power difference exceeds the threshold value, identifying the presence of the larger peak value; When the power difference does not exceed the threshold value, it is recognized that the two larger peaks exist.

4. A random access processing device based on frequency offset correction, arranged in a first node, characterized in that: include: a transmission and reception module, configured to receive a signal from a second node and feed back a round-trip transmission delay value to the second node, so that the second node adjusts the timing based on the round-trip transmission delay value and continues a subsequent random access process; a processing module connected to the transceiver module and configured to execute a detection procedure, wherein the detection procedure includes: performing correlation calculation on the received signal and the local sequence, and identifying the existence of one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence; an estimation module connected to the processing module and the transmission and reception module, and configured to estimate the round-trip transmission delay value according to the position of a larger peak value when the processing module identifies the existence of a larger peak value based on the result of the correlation calculation performed on the received signal and the local sequence; a frequency deviation correction module connected to the processing module, and configured to estimate the frequency deviation of the received signal based on the two larger peaks when the processing module identifies the existence of the two larger peaks, and perform frequency deviation correction on the received signal according to the frequency deviation, and transmit the received signal after the frequency deviation correction to the processing module, so that the processing module re-executes the detection procedure based on the received signal after the frequency deviation correction; Among them, if the processing module re-executes the detection procedure based on the received signal after frequency offset correction, and the result of the correlation calculation still identifies the existence of two larger peaks, the frequency offset correction module inverts the frequency offset and performs frequency offset soft calibration and the detection procedure on the received signal from the second node.

5. The random access processing device based on frequency offset correction according to claim 4, characterized in that: The processing module identifies the existence of the one or two larger peaks based on the result of the correlation calculation between the received signal and the local sequence, including: the processing module obtains multiple peaks based on the result of the correlation calculation between the received signal and the local sequence; the processing module selects the first N larger peaks based on the multiple peaks, wherein N is a positive integer greater than or equal to 2; the processing module determines the first N larger peaks that are separated by a distance of d u Whether the power difference between the two peaks exceeds the threshold value, wherein the d u d is the root sequence of ZC u when the processing module determines that the power difference exceeds the threshold value, it identifies the presence of the one larger peak value; when the processing module determines that the power difference does not exceed the threshold value, it identifies the presence of the two larger peak values.

6. The random access processing device based on frequency offset correction according to claim 4, characterized in that: The processing module identifies the existence of the one or two larger peaks based on the result of the correlation calculation performed on the received signal and the local sequence, including: the processing module obtains multiple peaks based on the result of the correlation calculation performed on the received signal and the local sequence; the processing module selects two largest peaks based on the multiple peaks, and determines whether the power difference between the two largest peaks exceeds a threshold value; when the processing module determines that the power difference exceeds the threshold value, it identifies the existence of the one larger peak; when the processing module determines that the power difference does not exceed the threshold value, it identifies the existence of the two larger peaks.

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