Frequency offset processing method, device and base station

Abstract

An embodiment of the present application provides a frequency offset processing method, apparatus, and base station. The method includes: for a data channel, calculating a theoretical Doppler frequency offset to form a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; converting the compensated signal from the time domain to the frequency domain, and performing reception processing to obtain a correlation estimate value; according to the validity judgment result of the frequency offset estimate value, performing frequency-domain frequency offset compensation in different ways to obtain a detection result; for an access channel, calculating a theoretical Doppler frequency offset to form a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; converting the compensated signal from the time domain to the frequency domain, extracting an effective signal in the frequency domain, and performing reception processing on the extracted effective signal to obtain a detection result of the access channel. The present application can effectively address the frequency offset problem and improve the communication quality in a high-speed mobile scenario.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a frequency offset processing method, apparatus, and base station. Background Art

[0002] With the rapid development of the high-speed rail industry, high-speed rail has become the preferred means of transportation for people, and the requirements for wireless communication and quality have been significantly improved. However, the rapid movement of high-speed rail trains leads to an increase in Doppler frequency offset, which has a serious impact on communication quality. In the data channel, the Doppler frequency offset causes distortion of the frequency-domain signal, destruction of the orthogonality of OFDM (Orthogonal Frequency-Division Multiplexing) subcarriers, and inter-carrier interference, thereby affecting the demodulation performance; in the access channel, the Doppler frequency offset affects the detection of PRACH (Physical Random Access Channel) and delay estimation, resulting in difficulties for users to access. In addition, in a multi-user high-speed movement scenario, the difference in Doppler frequency offset will cause multi-user frequency-domain interference, further reducing the signal-to-noise ratio. Summary of the Invention

[0003] Aiming at the problem of how to improve the communication quality in high-speed movement scenarios, this application provides a frequency offset processing method, apparatus, and base station.

[0004] In a first aspect, this application provides a frequency offset processing method. For the data channel: calculate the theoretical Doppler frequency offset to form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a time-domain to frequency-domain conversion on the compensated signal, and perform reception processing to obtain relevant estimation values; according to the validity judgment result of the frequency offset estimation value, perform frequency-domain frequency offset compensation in different ways to obtain a detection result;

[0005] For the access channel: calculate the theoretical Doppler frequency offset to form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a time-domain to frequency-domain conversion on the compensated signal, extract the effective signal in the frequency domain, and perform reception processing on the extracted effective signal to obtain the detection result of the access channel.

[0006] In a second aspect, this application also provides a frequency offset processing apparatus. The data channel processing module is used to calculate the theoretical Doppler frequency offset to form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a time-domain to frequency-domain conversion on the compensated signal, and perform reception processing to obtain relevant estimation values; according to the validity judgment result of the frequency offset estimation value, perform frequency-domain frequency offset compensation in different ways to obtain a detection result;

[0007] The access channel processing module is used to calculate the theoretical Doppler frequency offset and form a set of frequency offsets, and perform time-domain frequency offset compensation operations on the received signal according to the set of frequency offsets; perform a time-domain to frequency-domain conversion on the compensated signal, extract the valid signal in the frequency domain, and perform reception processing on the extracted valid signal to obtain the detection result of the access channel.

[0008] In a third aspect, the present application further provides a base station, and the base station is used to execute the steps of the frequency offset processing method described in any one of the first aspects.

[0009] A frequency offset processing method, device, and base station provided by an embodiment of the present application can improve communication quality by performing specific processing on the data channel and the access channel respectively in a high-speed mobile scenario. For the data channel, first calculate the theoretical Doppler frequency offset to form a set of frequency offsets and perform time-domain frequency offset compensation on the received signal accordingly, then perform a time-to-frequency conversion on the compensated signal and perform reception processing to obtain the relevant estimated value, and then perform frequency-domain frequency offset compensation in different ways according to the result of the validity judgment of the frequency offset estimate to obtain the detection result; for the access channel, also calculate the set of frequency offsets first and perform time-domain frequency offset compensation, then perform a time-to-frequency conversion and extract the valid signal in the frequency domain and perform reception processing to obtain the detection result of the access channel. By these steps, the frequency offset is effectively processed, thereby solving the problem of the decline in communication quality caused by the frequency offset in the high-speed mobile scenario.

[0010] Therefore, the present application can perform refined processing on the data channel and the access channel in a high-speed mobile scenario respectively. By accurately calculating and compensating the frequency offset, reasonably performing signal conversion and reception processing, it can effectively cope with the frequency offset problem, thereby improving the communication quality in the high-speed mobile scenario and ensuring the accuracy and reliability of communication. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0012] Figure 1 is a schematic diagram of the generation of the Doppler frequency offset of high-speed rail movement;

[0013] Figure 2 is a schematic diagram of the peak position in a high-speed scenario;

[0014] Figure 3 is a flowchart of the frequency offset processing method;

[0015] Figure 4 is a flowchart of the frequency offset processing method based on the data channel;

[0016] Figure 5 is a flowchart of a frequency offset processing method based on an access channel;

[0017] Figure 6 is a schematic diagram of the peak relationship after the first frequency offset processing;

[0018] Figure 7 is a structural block diagram of a frequency offset processing device. Detailed implementation manners

[0019] In the embodiments of the present application, the term "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. In the embodiments of the present application, the term "plurality" refers to two or more, and other quantifiers are similar thereto.

[0020] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0021] According to the Doppler frequency shift formula ( is the carrier frequency, is the moving speed, is the azimuth angle, is the speed of light), it can be seen that both the moving speed and the running direction will affect the magnitude of the Doppler frequency offset. In the multi-user high-speed mobile scenario, the Doppler frequency offset will destroy the orthogonality between subcarriers, thereby introducing additional interference between subcarriers, resulting in a decrease in the signal-to-noise ratio of the user, and further affecting the receiving performance of the user. For example, when the train moving speed reaches 500 km / h and the carrier frequency is 2.8 GHz, the maximum Doppler frequency offset calculated according to the above formula can reach 1296 Hz, which seriously affects the reception and detection of the uplink signal. Thus, it is necessary to overcome the influence of the Doppler frequency offset in the case of high-speed movement of the terminal.

[0022] Please refer to Figure 1 , Figure 1It is a schematic diagram of the Doppler frequency offset generated by high-speed rail movement. Assume there are N tracks, and the train heads on each track are regarded as one train user. The time-frequency resources of these N train users do not overlap. However, in high-speed scenarios, a large Doppler frequency offset will occur for each train user. The Doppler frequency offset is a frequency change phenomenon caused by the relative movement between the communication equipment on the train and the base station. This Doppler frequency offset, on the one hand, destroys the orthogonality between subcarriers, and on the other hand, causes energy leakage in the frequency domain. If train user i and train user j are in adjacent frequency domain positions, the frequency domain data of train user i may leak to the frequency domain of train user j, resulting in frequency domain interference among multiple train users. Moreover, the movement directions (such as the arrow directions in Figure 1 , the movement speeds (v1, v2, …, v N ), and the angles with the base station (such as θ1, θ2, …, θ N ) of each user are all different, which makes the Doppler frequency offsets generated by each train user different, and further leads to different interference situations among train users.

[0023] Pilot data, as a special signal data, is a known signal pattern specially sent by the sending end, aiming to assist the receiving end in obtaining channel state information, achieving synchronization, and performing frequency offset estimation and other operations. Traditional frequency offset estimation methods are based on pilot data and use the pilot data of multiple symbols to carry out frequency offset estimation work. The operation process is as follows: First, extract the pilot data of the user from the received signal; then, obtain the channel estimation value of each pilot symbol through channel estimation; after that, select the channel estimation values of two different pilot symbols for correlation calculation; then calculate the angle of the result after the correlation operation; after this series of operations, finally calculate the frequency offset estimation value. This frequency offset estimation value is an estimation result of the magnitude of the frequency offset existing in the received signal. The receiving end can perform subsequent frequency offset processing and other operations based on this estimation value to improve the receiving quality of the signal.

[0024] From the overall architecture of the communication system, the data channel and the access channel are important components. In the part of the data channel, there are some limitations in the traditional frequency offset estimation method related to pilot data. On the one hand, when the pilot symbol interval is large, the frequency offset estimation range shrinks. In high-speed mobile scenarios, the Doppler frequency offset is large, and the actual frequency offset is likely to exceed the range, causing the traditional frequency offset estimation value to flip and the estimation to be inaccurate, thereby reducing the receiving performance; on the other hand, traditional frequency offset processing only targets frequency domain signals and cannot solve the in-symbol interference caused by the Doppler frequency offset. In terms of the access channel, under the restricted set configuration, the traditional detection technology combines the main window and sub-window signals for preamble detection, which will increase the background noise and reduce the detection performance. Although the preamble detection under the non-restricted set can reduce the base station cost, the traditional detection method cannot use the non-restricted set access configuration in high-speed mobile scenarios.

[0025] In the process of frequency offset estimation based on pilot data, first, the received time-domain signal is subjected to a Fast Fourier Transform (FFT) to convert it to the frequency domain. In the frequency domain, the received data is extracted for each pilot symbol, and at the same time, the corresponding transmitted pilot data is generated. Subsequently, the channel estimation value of each pilot symbol is obtained through the transmitted and received pilot data. Then, the channel estimation values of two pilot symbols are selected for correlation operation, and the angle of the result after the correlation operation is calculated to obtain the frequency offset. After obtaining the frequency offset, a frequency offset processing operation is performed in the frequency domain. The entire process, from frequency offset estimation to frequency offset processing, is completed in the frequency domain.

[0026] In the high-speed rail scenario, due to the high-speed operation of the train, a large Doppler frequency offset will be generated. For the Physical Random Access Channel (PRACH), it is usually configured as a restricted set. When the Doppler frequency offset satisfies the relationship (where represents the subcarrier spacing of the PRACH, represents the Doppler frequency offset), the received PRACH time-domain signal will have energy dispersion compared to the original sequence, and the dispersed positions are located at of the cyclic shift, where is the cyclic shift value corresponding to the PRACH peak when .

[0027] Based on the above cyclic shift phenomenon, during PRACH peak detection, in addition to the correlation peak appearing at ( is the cyclic shift), a pseudo-correlation peak will also appear at (where is the PRACH sequence length). Define the search window where the correlation peak at is located as the main window, and define the search window next to the main window as the secondary window. In this way, secondary windows will appear.

[0028] The 3GPP protocol defines two restricted sets, namely restricted TypeA and restricted TypeB. For restricted TypeA, the Doppler frequency offset it can resist is (when K = 1), and in this case, 2 secondary windows (denoted as secondary windows 1 / 2) will be generated; for restricted TypeB, the Doppler frequency offset it can resist is (when K = 2), and in this case, 4 secondary windows (denoted as secondary windows 1, 2, 3, 4) will be generated, as shown in Figure 2 . In Figure 2 , the abscissa n (sc index) represents the time index, and the ordinate MF_ Out(n)Represents the output result after matched filtering processing; N cs Represents the offset related to the channel state; during PRACH peak detection, a correlation peak will appear at C v and the search window where the correlation peak at C v is located is defined as the main window. The traditional detection methods for restricted TypeA / B are three-window merging / five-window merging, that is, the energy of the main window is superimposed with the energy of all secondary windows, and then PRACH peak detection is performed. Three-window merging is to superimpose the energy of the main window with the energy of these 2 secondary windows (restricted TypeA will generate 2 secondary windows); five-window merging is to superimpose the energy of the main window with the energy of these 4 secondary windows (restricted TypeB will generate 4 secondary windows).

[0029] Please refer to Figure 3 , Figure 3 which is the flowchart of the frequency offset processing method. A frequency offset processing method, the frequency offset processing includes frequency offset estimation and frequency offset compensation, and the method includes:

[0030] S110, for the data channel: calculate the theoretical Doppler frequency offset and form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a time-domain to frequency-domain conversion on the compensated signal, and perform reception processing to obtain a correlation estimate; according to the validity judgment result of the frequency offset estimate, perform frequency-domain frequency offset compensation in different ways to obtain a detection result.

[0031] Exemplarily, calculating the theoretical Doppler frequency offset and forming a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set includes:

[0032] S111, according to the position information, moving speed, moving direction of the train, and the position and height information of the base station, calculate the corresponding theoretical Doppler frequency offset for each train user to obtain a first frequency offset set.

[0033] For example, according to the train position, moving speed and direction, and the base station position and height, calculate the theoretical Doppler frequency offset (i.e., the first frequency offset estimate) . If the number of trains is N (i.e., N train users), then N first frequency offset estimates are obtained, denoted as the first frequency offset set .

[0034] S112, use the frequency offset estimates in the first frequency offset set and the received first time-domain signal to perform a time-domain frequency offset compensation operation on the corresponding theoretical Doppler frequency offset of each train user to obtain a compensated second time-domain signal.

[0035] For example, according to the first frequency offset set The frequency offset estimation value in and the first time-domain signal (received signal) are used to perform time-domain frequency offset compensation on the th user to obtain a second time-domain signal.

[0036] Exemplarily, the compensated signal is converted from the time domain to the frequency domain and subjected to reception processing to obtain relevant estimation values including:

[0037] S113, convert the second time-domain signal from the time domain to the frequency domain to obtain a first frequency-domain signal.

[0038] S114, perform reception processing on the first frequency-domain signal. The reception processing includes estimating the channel characteristics, further estimating the frequency offset, and estimating the signal-to-interference-plus-noise ratio to obtain a new frequency offset estimation value for each train user and a first signal-to-interference-plus-noise ratio estimation value. The new frequency offset estimation values form a second frequency offset set.

[0039] For example, using the first frequency-domain signal for reception processing includes channel estimation, frequency offset estimation, and SINR (Signal to Interference plus Noise Ratio) estimation. The th train user's new frequency offset estimation value (i.e., the second frequency offset estimation value) is obtained and denoted as the th element in the second frequency offset set, and the th train user's first SINR estimation value is obtained. Among them, SINR is an important indicator for measuring the signal quality in a communication system, which reflects the ratio of the signal strength to the sum of the interference and noise strengths. The higher the value of SINR, the better the signal quality and the better the performance of the communication system.

[0040] Exemplarily, according to the validity judgment result of the frequency offset estimation value, different methods are used for frequency-domain frequency offset compensation to obtain detection results including:

[0041] S115, if the absolute value of the new frequency offset estimation value of a certain train user is less than a preset estimation deviation threshold, it is determined that the initial theoretical Doppler frequency offset estimation value (i.e., the first frequency offset estimation value) of the train user is valid and the new frequency offset estimation value (i.e., the second frequency offset estimation value) has not flipped; use the first frequency-domain signal and the new frequency offset estimation value to perform frequency-domain frequency offset compensation operation on the train user to obtain the detection result of the train user.

[0042] For example, according to the second frequency offset set calculated by S114

[0043] the th frequency offset value in, for the first frequency offset set in perform a validity judgment:

[0044] If , then it is determined that the first frequency offset estimation value of the th train user is valid, and the second frequency offset estimation value has not flipped. Among them, is a preset estimation deviation threshold value. At this time, use the first frequency domain signal and the th frequency offset value in the second frequency offset set to perform frequency domain frequency offset compensation on the th train user, and further obtain the detection result of this train user.

[0045] S116. If the absolute value of the new frequency offset estimation value of a certain train user is greater than the preset estimation deviation threshold value, then perform a time-domain to frequency-domain conversion on the first time-domain signal to obtain a second frequency-domain signal, and then perform reception processing on the second frequency-domain signal to obtain a second signal-to-interference-plus-noise ratio estimation value.

[0046] For example, if is not satisfied, then it is determined that the first frequency offset estimation value of the th train user may be invalid, and perform a time-to-frequency conversion on the first time-domain signal of the th train user to obtain a second frequency-domain signal. Then use the second frequency-domain signal to perform reception processing to obtain the second SINR estimation of the th train user.

[0047] Exemplarily, based on step S116, the method further includes:

[0048] If the second signal-to-interference-plus-noise ratio estimation value is greater than the first signal-to-interference-plus-noise ratio estimation value, then perform reception processing on the second frequency-domain signal to obtain the detection result of this train user.

[0049] For example, if the second SINR estimation value is greater than the first SINR estimation value, it is considered that the first frequency offset estimation value of the th train user may be invalid. Use the second frequency-domain signal to perform reception processing, and further obtain the detection result of this train user.

[0050] If the second signal-to-interference-plus-noise ratio estimation value is less than or equal to the first signal-to-interference-plus-noise ratio estimation value, then it is determined that the initially theoretical Doppler frequency offset estimation value of this train user is valid, and perform a frequency domain frequency offset compensation operation on this train user using the first frequency domain signal and the new frequency offset estimation value to obtain the detection result of this train user.

[0051] For example, if the second SINR estimation value is less than or equal to the first SINR estimation value, it is determined that the first frequency offset estimation value of the nth train user is valid. Using the first frequency-domain signal and the nth frequency offset value in the second frequency offset set , frequency-domain frequency offset compensation is performed on the nth train user. And the detection result of this train user is further obtained.

[0052] Exemplarily, the method further includes:

[0053] Repeatedly execute step S112 to step S116 to traverse all the frequency offset values in the first frequency offset set to complete the processing operation of the data channels of all train users.

[0054] S120, for the access channel: calculate the theoretical Doppler frequency offset and form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a time-domain to frequency-domain conversion on the compensated signal, extract the valid signal in the frequency domain, and perform reception processing on the extracted valid signal to obtain the detection result of the access channel.

[0055] Exemplarily, calculating the theoretical Doppler frequency offset and forming a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set includes:

[0056] S121, calculate the corresponding theoretical Doppler frequency offset for each train user according to the position information, moving speed, moving direction of the train, and the position and height information of the base station to obtain the first frequency offset set.

[0057] For example, calculate the theoretical Doppler frequency offset according to the train position, moving speed and direction, and the position and height of the base station . If the number of trains is N (i.e., N train users), then N first frequency offsets are obtained, denoted as the first frequency offset set .

[0058] S122, use the frequency offset estimation value in the first frequency offset set and the received first time-domain signal to perform a time-domain frequency offset compensation operation on the corresponding theoretical Doppler frequency offset of each train user to obtain the compensated second time-domain signal.

[0059] For example, according to the frequency offset estimation value in the first frequency offset set and the first time-domain signal (received signal), perform time-domain frequency offset compensation on the nth user to obtain the second time-domain signal.

[0060] Exemplarily, the compensated signal is converted from the time domain to the frequency domain, the valid signal is extracted in the frequency domain, and the received processing is performed on the extracted valid signal to obtain the detection result of the access channel, including:

[0061] S123, convert the second time-domain signal from the time domain to the frequency domain, and extract the valid physical random access channel frequency-domain signal in the frequency domain.

[0062] S124, perform received processing on the extracted signal, where the received processing includes matched filtering and preamble detection operations; when performing preamble detection, only based on the energy of the main window, without performing three-window merging or five-window merging operations, and the user corresponding to the preamble detected by the main window is a valid user.

[0063] Specifically, PRACH is a channel used by user equipment (such as a mobile phone) to initiate a random access request to the base station in a wireless communication system. When the user equipment needs to access the network, it will send a specific preamble sequence through PRACH, and the base station identifies and admits users by detecting these preambles. In traditional PRACH detection methods, especially when a restricted set is configured, three-window merging or five-window merging is usually adopted. The purpose of the merging operation is to synthesize the signal information in multiple windows to improve the accuracy and reliability of detection. For example, by merging the signals of the main window and multiple secondary windows, and then performing preamble detection based on the merged signal to determine whether there is a user access. However, the detection method provided in this application no longer performs three-window merging or five-window merging operations, but only focuses on the peak value in the main window. The peak value in the main window usually represents the part with the strongest signal energy, that is, the part most likely to contain a valid preamble. For example, when analyzing the received PRACH signal, only look for the point with the maximum signal strength (i.e., the peak value) within the main window range.

[0064] When a peak value is detected in the main window and the peak value meets certain detection conditions (such as exceeding a preset threshold), it is considered that a valid preamble has been detected. Correspondingly, the user who sent the preamble is regarded as a valid user. This method in this application simplifies the detection process and directly determines the valid user according to the detection result of the main window, avoiding some problems that may be brought by multi-window merging, such as the uplift of the background noise.

[0065] Therefore, the detection method provided in this application does not require complex multi-window merging operations, reduces the amount of calculation and processing time, improves the detection efficiency, and is especially suitable for scenarios with high real-time requirements. Since no window merging is performed, the problem of background noise uplift caused by the merging operation is avoided, thereby improving the accuracy and reliability of detection and being able to more effectively identify the real valid users.

[0066] Exemplarily, the method further includes:

[0067] Repeat steps S122 to S124 to traverse all the frequency offset values in the first frequency offset set to complete the processing operation of the access channels of all train users.

[0068] In summary, the frequency offset processing method described in this application can solve multiple problems related to frequency offset estimation and signal detection: First, when the pilot symbol interval is large, the frequency offset estimation range becomes smaller. In a high-speed moving scenario, the actual frequency offset may exceed the range, resulting in the inversion and inaccuracy of the frequency offset estimation value of the traditional method, and further reducing the reception performance; Second, traditional frequency offset compensation is only performed on the frequency domain signal and cannot recover the in-symbol interference caused by the user Doppler frequency offset; Third, when the traditional detection technology configures the restricted set, the main window and the secondary window are combined for preamble detection, which will increase the background noise and lead to a decrease in detection performance; Fourth, although the preamble detection under the non-restricted set is simpler, easier to implement, and can reduce the base station cost, in a high-speed moving scenario, the traditional detection method cannot use the non-restricted set access configuration. Specifically:

[0069] (1) To address the problems of small frequency offset estimation range and estimation value inversion, the following solutions are adopted:

[0070] a. Calculate the theoretical Doppler frequency offset and perform time-domain compensation. That is, according to the position, movement speed, direction of the train, and the position and height information of the base station, calculate the corresponding theoretical Doppler frequency offset for each train user to form the first frequency offset set. Use the frequency offset estimation value in this set to perform time-domain frequency offset compensation on the received first time-domain signal to obtain the second time-domain signal. In this way, the frequency offset is compensated at the initial stage to avoid the actual frequency offset exceeding the estimation range.

[0071] b. Determine the validity of the frequency offset estimation value and perform compensation adjustment. That is, convert the second time-domain signal to the frequency domain to obtain the first frequency domain signal, and perform reception processing to obtain a new frequency offset estimation value (forming the second frequency offset set), the first signal-to-interference-plus-noise ratio (SINR) estimation value, etc. If the absolute value of the new frequency offset estimation value is less than the preset estimation deviation threshold, it is determined that the initially calculated theoretical Doppler frequency offset estimation value is valid and has not been inverted, and the first frequency domain signal and the new estimation value are used for frequency-domain frequency offset compensation to obtain the detection result; if it is greater than the threshold, it is determined that the initially calculated value may be invalid, and further determine the final frequency offset compensation and detection method by comparing the SINR estimation values under different processing methods. For example, reprocess the first time-domain signal to obtain the second frequency domain signal and perform reception processing to obtain the second SINR estimation value, and determine whether the initially calculated value is valid based on its relationship with the first SINR estimation value, and then select the appropriate frequency domain signal and estimation value for frequency offset compensation and obtain the detection result.

[0072] (3) To address the problem of irreparable in-symbol interference, the following solutions are adopted:

[0073] Time-domain frequency offset compensation, that is, the operation of forming a frequency offset set through the above-mentioned calculation of the theoretical Doppler frequency offset and performing time-domain frequency offset compensation. The frequency offset is processed in the time domain, rather than relying solely on frequency-domain frequency offset compensation. This can reduce the in-symbol interference caused by the Doppler frequency offset because the time-domain compensation can more directly adjust according to the time characteristics of the signal, thereby improving the in-symbol interference problem caused by the frequency offset.

[0074] (3) To solve the problem of the baseband noise floor increase caused by signal combination, the following solutions are adopted:

[0075] Simplify the preamble detection, that is, when processing the second time-domain signal, convert it to the frequency domain and extract the effective PRACH frequency-domain signal. When performing matched filtering and preamble detection, only consider the main window energy and do not perform three-window combination or five-window combination operations. This avoids the problem of baseband noise floor increase caused by signal combination. The preamble detected by the main window is regarded as a valid user, which can more accurately detect the valid signal and improve the detection performance.

[0076] (4) To solve the problem that non-restricted set access configuration cannot be used in high-speed mobile scenarios, the following solutions are adopted:

[0077] Optimize the detection method, that is, adopt the above-mentioned preamble detection method that only considers the main window energy and does not perform window combination. To a certain extent, it improves the accuracy and efficiency of detection. This relatively simplified detection method is closer to the detection characteristics under the non-restricted set, enabling more effective signal detection in high-speed mobile scenarios, thereby realizing non-restricted set access configuration and reducing the base station cost.

[0078] The following specifically describes the frequency offset processing method of the present application through embodiments.

[0079] Please refer to Figure 4 , Figure 4 which is a flowchart of the frequency offset processing method based on the data channel. A frequency offset processing method includes:

[0080] S401, calculate the first frequency offset estimation value of each train user to obtain the first frequency offset set.

[0081] Assume the number of tracks is . Assume the preset moving speed of the train on each track is . According to the position information of the train, the moving direction of the train, and the height of the base station, the azimuth angle between the train and the base station can be obtained. According to the Doppler frequency offset calculation formula: , the Doppler frequency offset of each train can be calculated, denoted as the first frequency offset estimation value , the set composed of the first frequency offset estimation values is denoted as the first frequency offset set .

[0082] S402. Perform time-domain frequency offset compensation on the first time-domain signal to obtain a second time-domain signal.

[0083] Utilize the first frequency offset estimation set calculated in step S401 in the first frequency offset estimation values to perform time-domain frequency offset compensation on the first time-domain signal (the received signal) to obtain a second time-domain signal

[0084] According to the properties of Fourier transform, frequency offset is reflected as phase offset in the time domain. Perform frequency offset compensation on the time-domain signal at the nth sampling moment. The compensated second time-domain signal is:

[0085]

[0086] In the formula, is the sampling rate, , represents the number of FFT points, is the subcarrier spacing.

[0087] S403. Perform time-to-frequency conversion on the second time-domain signal to obtain a first frequency-domain signal.

[0088] S404. Perform reception processing on the first frequency-domain signal to obtain a second frequency offset estimation value and a first signal-to-interference-plus-noise ratio (SINR) estimation value.

[0089] Perform time-to-frequency conversion on the second time-domain signal to obtain a first frequency-domain signal. In the frequency domain, according to the resource position of the nth train user, extract the effective frequency-domain data of the nth train user, and then perform reception processing, including channel estimation, frequency offset estimation, and SINR estimation. At this time, the second frequency offset estimation value of the nth train user can be obtained. The set composed of these values is denoted as the second frequency offset set . At the same time, the first SINR estimation value of the nth user is obtained.

[0090] S405. Determine whether the absolute value of the second frequency offset estimation value is less than a preset estimation deviation threshold.

[0091] Set the estimation deviation threshold . According to the second frequency offset set calculated in step S404 in the a second frequency offset estimation value , determine the validity of the th first frequency offset estimation value in the first frequency offset set.

[0092] If the absolute value of the second frequency offset estimation value is less than a preset estimation deviation threshold, execute S406; otherwise, execute S408.

[0093] S406, the first frequency offset estimation value of the train user is valid, and the second frequency offset estimation value has not flipped.

[0094] Among them, if is satisfied, it is determined that the th first frequency offset estimation value of the train user is valid, and the second frequency offset estimation value has not flipped. For the target train user , the first frequency offset estimation value is used to calculate the theoretical Doppler frequency offset. If is valid, after the train user has undergone first frequency offset compensation, the remaining frequency offset is very small and will not flip, that is, the second frequency offset estimation value is small, usually less than , and

[0095] S407, use the first frequency domain signal and the second frequency offset estimation value to perform frequency domain frequency offset compensation operation on the train user to obtain the detection result of the train user.

[0096] For the train user , use the first frequency domain signal and the second frequency offset estimation value in the second frequency offset set to perform frequency domain frequency offset compensation, and further obtain the detection result of the train user.

[0097] S408, perform time-to-frequency conversion on the first time domain signal to obtain a second frequency domain signal.

[0098] If is not satisfied, it is considered that the th first frequency offset estimation value of the train user may be invalid. For the th train user, perform time-to-frequency conversion on the first time domain signal to obtain a second frequency domain signal.

[0099] S409, perform reception processing on the second frequency domain signal to obtain a second signal-to-interference-plus-noise ratio estimation value.

[0100] Receive and process the second frequency-domain signal to obtain the second SINR estimate of the th train user.

[0101] S410. Determine whether the second signal-to-interference-plus-noise ratio estimate is greater than the first signal-to-interference-plus-noise ratio estimate.

[0102] If the second signal-to-interference-plus-noise ratio estimate is greater than the first signal-to-interference-plus-noise ratio estimate, execute S411; otherwise, return to execute S407, that is, perform frequency-domain frequency offset compensation on this train user using the first frequency-domain signal and the second frequency offset estimate to obtain the detection result of this train user.

[0103] S411. Receive and process the second frequency-domain signal to obtain the detection result of this train user.

[0104] If the second SINR estimate is greater than the first SINR estimate, it is determined that the first frequency offset estimate of the th train user is invalid. At this time, for the train user

[0105] perform reception processing using the second frequency-domain signal, and further obtain the detection result of this train user. If the second SINR estimate is less than or equal to the first SINR estimate, it is determined that the first frequency offset estimate of the th train user is valid. At this time, for the train user perform frequency-domain frequency offset compensation using the first frequency-domain signal and the second frequency offset estimate in the

[0106] second frequency offset set Figure 5 and further obtain the detection result of this train user. Figure 5 Please refer to

[0107] which is a flowchart of a frequency offset processing method based on an access channel. A frequency offset processing method includes:

[0108] S501. Calculate the first frequency offset estimate of each train user to obtain the first frequency offset set. Assume the number of tracks is . Assume the preset moving speed of the train on each track is . According to the position information of the train, the moving direction of the train, and the height of the base station, the azimuth angle between the train and the base station can be obtained . According to the Doppler frequency offset calculation formula: , the Doppler frequency offset of each train can be calculated, denoted as the first frequency offset estimate . The set composed of the first frequency offset estimates is denoted as the first frequency offset set

[0109] S502. Perform time-domain frequency offset compensation on the first time-domain signal to obtain a second time-domain signal.

[0110] Use the first frequency offset estimation set calculated in step S401 The first frequency offset estimation value in Perform time-domain frequency offset compensation on the first time-domain signal (the received signal) To obtain a second time-domain signal ;

[0111] According to the properties of Fourier transform, frequency offset is reflected as phase offset in the time domain. Perform frequency offset compensation on the time-domain signal at the th sampling moment. The compensated second time-domain signal is:

[0112]

[0113] In the formula, Is the sampling rate, , Represents the number of FFT points, Is the subcarrier spacing.

[0114] S503. Perform time-to-frequency conversion on the second time-domain signal, extract the effective physical random access channel frequency-domain signal in the frequency domain, and perform reception processing on the extracted signal.

[0115] Perform reception processing on the second time-domain signal . After time-to-frequency conversion, extract the effective PRACH frequency offset data according to the resource location of PRACH, denoted as . Multiply the received PRACH signal By the base sequence in the frequency domain, and then perform IDFT to convert it to the time domain to obtain the result after correlation, denoted as .

[0116] For train users , after performing time-domain frequency offset compensation using the first frequency offset estimation value In the time domain in step S502, it can be determined that the remaining frequency offset in train users Is very small, far less than the subcarrier spacing of PRACH. It is determined that the energy of this train user is all concentrated in the main peak, and the energy of the false correlation peak is very small. Therefore, the sequence Will only generate a correlation peak at , and will not generate a correlation peak or the correlation peak value is very small at , as shown in Figure 6 . At this time, the detection of PRACH only requires the peak value in the main window, without performing three-window merging or five-window merging. The users detected in the main window are considered valid users.

[0117] Therefore, after performing frequency offset compensation by using the first frequency offset estimation value in the time domain the residual frequency offset of the train user is extremely small, and the energy is almost all concentrated in the main peak, while the energy of the pseudo-correlation peak is weak. Therefore, for PRACH detection, only the peak value in the main window needs to be concerned, without complex merging calculations (such as three-window merging or five-window merging). This optimization method of the present application simplifies the detection process, reduces the computational complexity and resource consumption, and at the same time improves the detection efficiency and accuracy, and can quickly identify valid users and adapt to the frequency offset challenges brought by high-speed movement in the high-speed rail scenario.

[0118] Next, the frequency offset processing device provided by the present application will be described. The frequency offset processing device described below can be correspondingly referred to the frequency offset processing method described above.

[0119] Please refer to Figure 7 , Figure 7 which is the structural diagram of the frequency offset processing device. A frequency offset processing device 700, the device includes a data channel processing module 710 and an access channel processing module 720.

[0120] Exemplarily, the data channel processing module 710 is used to calculate the theoretical Doppler frequency offset and form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a conversion from the time domain to the frequency domain on the compensated signal, and perform reception processing to obtain a correlation estimation value; according to the validity judgment result of the frequency offset estimation value, perform frequency-domain frequency offset compensation in different ways to obtain a detection result.

[0121] Exemplarily, the access channel processing module 720 is used to calculate the theoretical Doppler frequency offset and form a frequency offset set, and perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; perform a conversion from the time domain to the frequency domain on the compensated signal, extract the effective signal in the frequency domain, and perform reception processing on the extracted effective signal to obtain the detection result of the access channel.

[0122] Exemplarily, the data channel processing module 710 is further used for:

[0123] calculate the theoretical Doppler frequency offset according to the train and base station information, and use the frequency offset set to compensate the time-domain signal to generate a second compensated time-domain signal, which specifically includes:

[0124] The calculation of the theoretical Doppler frequency offset and the formation of the frequency offset set, and the performance of the time-domain frequency offset compensation operation on the received signal according to the frequency offset set include:

[0125] calculate the corresponding theoretical Doppler frequency offset for each train user according to the position information, moving speed, moving direction of the train and the position and height information of the base station to obtain a first frequency offset set;

[0126] Using the frequency offset estimation values in the first frequency offset set and the received first time-domain signal, perform a time-domain frequency offset compensation operation on the theoretical Doppler frequency offset corresponding to each train user to obtain a compensated second time-domain signal.

[0127] Exemplarily, the data channel processing module 710 is further configured to:

[0128] Convert the compensated second time-domain signal to the frequency domain to obtain a first frequency-domain signal, and obtain a new frequency offset and a signal-to-interference-plus-noise ratio (SINR) estimation value through reception processing (including channel, frequency offset, and SINR estimation), specifically including:

[0129] The conversion of the compensated signal from the time domain to the frequency domain and the reception processing to obtain relevant estimation values include:

[0130] Convert the second time-domain signal from the time domain to the frequency domain to obtain a first frequency-domain signal;

[0131] Perform reception processing on the first frequency-domain signal. The reception processing includes estimating the channel characteristics, further estimating the frequency offset, and estimating the SINR to obtain a new frequency offset estimation value and a first SINR estimation value for each train user. The new frequency offset estimation values form a second frequency offset set.

[0132] Exemplarily, the data channel processing module 710 is further configured to:

[0133] According to the comparison between the new frequency offset estimation value and the threshold value, perform frequency-domain compensation on the valid-value users to obtain detection results, and re-convert and process the invalid-value users in the frequency domain, specifically including:

[0134] If the absolute value of the new frequency offset estimation value of a certain train user is less than a preset estimation deviation threshold value, it is determined that the initial theoretical Doppler frequency offset estimation value of this train user is valid and the new frequency offset estimation value has not flipped; use the first frequency-domain signal and the new frequency offset estimation value to perform a frequency-domain frequency offset compensation operation on this train user to obtain the detection result of this train user;

[0135] If the absolute value of the new frequency offset estimation value of a certain train user is greater than a preset estimation deviation threshold value, convert the first time-domain signal from the time domain to the frequency domain to obtain a second frequency-domain signal, and then perform reception processing on the second frequency-domain signal to obtain a second SINR estimation value.

[0136] Exemplarily, the data channel processing module 710 is further configured to:

[0137] According to the comparison result between the second SINR estimation value and the first SINR estimation value, determine the validity of the theoretical Doppler frequency offset estimation value, and then adopt corresponding operations to obtain the detection results of the train users, specifically including:

[0138] If the second signal-to-interference-plus-noise ratio (SINR) estimation value is greater than the first SINR estimation value, perform reception processing on the second frequency-domain signal to obtain the detection result of the train user;

[0139] If the second SINR estimation value is less than or equal to the first SINR estimation value, determine that the initially estimated value of the theoretical Doppler frequency offset of the train user is valid, and perform frequency-domain frequency offset compensation operation on the train user using the first frequency-domain signal and the new frequency offset estimation value to obtain the detection result of the train user.

[0140] Exemplarily, the data channel processing module 710 is further configured to:

[0141] Repeat the above steps to traverse all the frequency offset values in the first frequency offset set, and complete the processing operation of the data channels of all train users.

[0142] Exemplarily, the access channel processing module 720 is further configured to:

[0143] Convert the second time-domain signal to the frequency domain, extract the PRACH frequency-domain signal, and perform matched filtering and primary window preamble detection without combining the secondary windows. The user detected by the primary window is a valid user, specifically including:

[0144] Convert the second time-domain signal from the time domain to the frequency domain, and extract the effective physical random access channel frequency-domain signal in the frequency domain;

[0145] Perform reception processing on the extracted signal. The reception processing includes matched filtering and preamble detection operations; when performing preamble detection, only rely on the energy of the primary window, without performing three-window combination or five-window combination operations. The user corresponding to the preamble detected by the primary window is a valid user.

[0146] Exemplarily, the access channel processing module 720 is further configured to:

[0147] Repeat the above steps to traverse all the frequency offset values in the first frequency offset set, and complete the processing operation of the access channels of all train users.

[0148] In some embodiments, the present application further provides a base station, and the base station is configured to execute the steps of the frequency offset processing method in the above embodiments.

[0149] Exemplarily, the specific process of the base station executing the frequency offset processing method is as follows:

[0150] (1) Calculate the theoretical Doppler frequency offset and perform time-domain frequency offset compensation.

[0151] Calculating the theoretical Doppler frequency offset: The base station calculates the corresponding theoretical Doppler frequency offset for each train user based on the train's position information, moving speed, moving direction, and the position and height information of the base station itself, thereby obtaining the first frequency offset set.

[0152] Performing time-domain frequency offset compensation operation: Using the frequency offset estimation values in the first frequency offset set and the received first time-domain signal, perform time-domain frequency offset compensation operation on the theoretical Doppler frequency offset corresponding to each train user to obtain the compensated second time-domain signal.

[0153] (2) Perform time-domain to frequency-domain conversion and reception processing on the compensated signal.

[0154] Time-domain to frequency-domain conversion: The base station converts the second time-domain signal from the time domain to the frequency domain to obtain the first frequency-domain signal.

[0155] Reception processing: Perform reception processing on the first frequency-domain signal, which includes estimating the channel characteristics, further estimating the frequency offset, and estimating the signal-to-interference-plus-noise ratio, thereby obtaining a new frequency offset estimation value for each train user and the first signal-to-interference-plus-noise ratio estimation value. The new frequency offset estimation values form the second frequency offset set.

[0156] (3) Perform frequency-domain frequency offset compensation according to the result of the frequency offset estimation value validity judgment.

[0157] Judging the validity of the frequency offset estimation value: Compare the absolute value of the new frequency offset estimation value of a certain train user with a preset estimation deviation threshold.

[0158] If it is less than the threshold: Determine that the initially estimated value of the theoretical Doppler frequency offset of this train user is valid and the new frequency offset estimation value has not flipped. Then use the first frequency-domain signal and the new frequency offset estimation value to perform frequency-domain frequency offset compensation operation on this train user to obtain the detection result of this train user.

[0159] If it is greater than the threshold: Determine that the initially estimated value of the theoretical Doppler frequency offset of this train user may be invalid. Convert the first time-domain signal from the time domain to the frequency domain to obtain the second frequency-domain signal, and then perform reception processing on the second frequency-domain signal to obtain the second signal-to-interference-plus-noise ratio estimation value.

[0160] (4) Judge and obtain the detection result according to the signal-to-interference-plus-noise ratio estimation value.

[0161] Comparing the signal-to-interference-plus-noise ratio estimation values: Compare the second signal-to-interference-plus-noise ratio estimation value with the first signal-to-interference-plus-noise ratio estimation value.

[0162] If the second signal-to-interference-plus-noise ratio estimation value is greater than the first signal-to-interference-plus-noise ratio estimation value: Determine that the initially estimated value of the theoretical Doppler frequency offset of this train user may be invalid, and perform reception processing on the second frequency-domain signal to obtain the detection result of this train user.

[0163] If the second signal-to-interference-plus-noise ratio (SINR) estimation value is less than or equal to the first SINR estimation value: Determine that the initially estimated theoretical Doppler frequency offset value of the train user is valid, and perform frequency-domain frequency offset compensation operation on the train user using the first frequency-domain signal and the new frequency offset estimation value to obtain the detection result of the train user.

[0164] (5) Extract the frequency-domain signal of the physical random access channel and obtain the detection result of the access channel.

[0165] Extract the frequency-domain signal: Convert the second time-domain signal from the time domain to the frequency domain, and extract the effective frequency-domain signal of the physical random access channel in the frequency domain.

[0166] Obtain the detection result of the access channel: Perform reception processing on the extracted signal, including matched filtering and preamble detection operations. When performing preamble detection, only rely on the energy of the main window, without performing three-window merging or five-window merging operations. The user corresponding to the preamble detected by the main window is the valid user.

[0167] Therefore, the base station provided by this application has the following advantages by finely processing the frequency offset problem in high-speed mobile scenarios: First, the base station can accurately calculate and compensate the frequency offset to ensure the accuracy and reliability of the signal; Second, through the conversion from the time domain to the frequency domain and reception processing, it can effectively extract and process the frequency-domain signal of the physical random access channel, simplify the detection process, and improve the detection efficiency; Finally, according to the judgment of the frequency offset estimation value and the SINR estimation value, flexibly adjust the frequency-domain frequency offset compensation strategy to ensure accurate detection results can be obtained under different conditions, thereby comprehensively improving the communication quality in high-speed mobile scenarios.

[0168] It should be noted here that the above-mentioned device and base station provided by the embodiments of this application can implement all the method steps implemented by the above method embodiments, and can achieve the same technical effects. Here, the same parts and beneficial effects as those in the method embodiments in this embodiment will not be specifically described again.

[0169] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. In this way, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application also intends to include these modifications and variations.

Claims

1. A frequency offset processing method, characterized in that, The method includes: For the data channel: calculating the theoretical Doppler frequency offset and forming a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; converting the compensated signal from the time domain to the frequency domain, and performing reception processing to obtain relevant estimation values; according to the comparison result between the frequency offset estimation value and a preset threshold value, selecting a corresponding frequency-domain frequency offset compensation method to obtain a detection result; for the access channel: calculating the theoretical Doppler frequency offset and forming a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; converting the compensated signal from the time domain to the frequency domain, extracting an effective signal in the frequency domain, and obtaining a detection result of the access channel through a main window energy detection method.

2. The frequency offset processing method according to claim 1, wherein the calculating the theoretical Doppler frequency offset and forming a frequency offset set, and performing a time-domain frequency offset compensation operation on the received signal according to the frequency offset set includes: calculating a corresponding theoretical Doppler frequency offset for each train user according to the position information, moving speed, moving direction of the train, and the position and height information of the base station, to obtain a first frequency offset set; using the frequency offset estimation value in the first frequency offset set and the received first time-domain signal to perform a time-domain frequency offset compensation operation on the corresponding theoretical Doppler frequency offset of each train user, to obtain a compensated second time-domain signal.

3. The frequency offset processing method according to claim 2, wherein the converting the compensated signal from the time domain to the frequency domain, and performing reception processing to obtain relevant estimation values includes: converting the second time-domain signal from the time domain to the frequency domain to obtain a first frequency-domain signal; performing reception processing on the first frequency-domain signal, where the reception processing includes estimating the channel characteristics, further estimating the frequency offset, and estimating the signal-to-interference-plus-noise ratio, to obtain a new frequency offset estimation value and a first signal-to-interference-plus-noise ratio estimation value for each train user, and the new frequency offset estimation values form a second frequency offset set.

4. The frequency offset processing method according to claim 3, wherein the according to the comparison result between the frequency offset estimation value and a preset threshold value, selecting a corresponding frequency-domain frequency offset compensation method to obtain a detection result includes: if the absolute value of the new frequency offset estimation value of a certain train user is less than a preset estimation deviation threshold value, it is determined that the initially estimated theoretical Doppler frequency offset value of this train user is valid and the new frequency offset estimation value has not flipped; using the first frequency-domain signal and the new frequency offset estimation value to perform a frequency-domain frequency offset compensation operation on this train user to obtain a detection result of this train user; if the absolute value of the new frequency offset estimation value of a certain train user is greater than a preset estimation deviation threshold value, converting the first time-domain signal from the time domain to the frequency domain to obtain a second frequency-domain signal, and then performing reception processing on the second frequency-domain signal to obtain a second signal-to-interference-plus-noise ratio estimation value.

5. The frequency offset processing method according to claim 4, wherein the method further includes: if the second signal-to-interference-plus-noise ratio estimation value is greater than the first signal-to-interference-plus-noise ratio estimation value, performing reception processing on the second frequency-domain signal to obtain a detection result of this train user; If the second signal-to-interference-plus-noise ratio (SINR) estimation value is less than or equal to the first SINR estimation value, it is determined that the initially estimated theoretical Doppler frequency offset value of the train user is valid, and the frequency-domain frequency offset compensation operation is performed on the train user using the first frequency-domain signal and the new frequency offset estimation value to obtain the detection result of the train user.

6. The frequency offset processing method according to claim 2, wherein: The conversion of the compensated signal from the time domain to the frequency domain, extracting the effective signal in the frequency domain, and obtaining the detection result of the access channel through the main window energy detection method include: Converting the second time-domain signal from the time domain to the frequency domain, and extracting the effective physical random access channel frequency-domain signal in the frequency domain; Performing reception processing on the extracted signal, where the reception processing includes matched filtering and preamble detection operations; when performing preamble detection, only based on the energy of the main window, without performing three-window merging or five-window merging operations, and the user corresponding to the preamble detected by the main window is the valid user.

7. The frequency offset processing method according to claim 5, wherein: The method further includes: Repeatedly executing the steps of claims 3 to 5 to traverse all the frequency offset values in the first frequency offset set, and completing the processing operation of the data channels of all train users.

8. The frequency offset processing method according to claim 6, wherein: The method further includes: Repeatedly executing the steps of claim 6 to traverse all the frequency offset values in the first frequency offset set, and completing the processing operation of the access channels of all train users.

9. A frequency offset processing device, characterized in that, The device includes: A data channel processing module, configured to calculate the theoretical Doppler frequency offset and form a frequency offset set, perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; convert the compensated signal from the time domain to the frequency domain, and perform reception processing to obtain relevant estimation values; select a corresponding frequency-domain frequency offset compensation method according to the comparison result between the frequency offset estimation value and a preset threshold value to obtain the detection result; An access channel processing module, configured to calculate the theoretical Doppler frequency offset and form a frequency offset set, perform a time-domain frequency offset compensation operation on the received signal according to the frequency offset set; convert the compensated signal from the time domain to the frequency domain, extract the effective signal in the frequency domain, and obtain the detection result of the access channel through the main window energy detection method.

10. A base station, characterized in that, The base station is configured to execute the steps of the frequency offset processing method according to any one of claims 1 to 8.

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