Interference detection method, device and equipment for OFDM signal, medium and product

Abstract

The application discloses an OFDM signal interference detection method, device, equipment, medium and product. The method comprises the following steps: receiving an OFDM signal to be detected, each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix with a length of L sampling points and useful symbol data with a length of N sampling points, and the cyclic prefix is obtained by copying a tail symbol with a length of L sampling points in the useful symbol; extracting cyclic prefix data and tail symbol data with a length of L sampling points of the OFDM signal to be detected, and determining a first noise power of the OFDM signal to be detected in the time domain according to the cyclic prefix data and the tail symbol data; determining a second noise power of the OFDM signal to be detected in the frequency domain; and determining whether the OFDM signal to be detected has interference according to the first noise power and the second noise power. The signal quality requirement is low, and the prior information of the interference is not required, so that the existence of the interference can be detected.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a method, apparatus, device, medium, and product for detecting interference in OFDM signals. Background Technology

[0002] OFDM, as a multi-carrier modulation technique, has been widely used in various wireless communication systems due to its advantages such as high spectral efficiency and strong resistance to multipath fading. In OFDM systems, the cyclic prefix (CP) is a key technical feature, which transforms the linear convolution of the channel into a cyclic convolution, thereby eliminating inter-symbol interference and maintaining the orthogonality between subcarriers.

[0003] In real-world communication environments, OFDM systems face various interference threats, including narrowband interference, impulse interference, co-channel interference, and adjacent-channel interference. These interferences can severely impact system reception performance, leading to increased bit error rate, decreased throughput, and even communication outages. Therefore, rapid and accurate detection of interference is crucial for ensuring the reliable operation of communication systems.

[0004] The presence of a cyclic prefix (CRF) allows the receiver to achieve symbol synchronization by detecting the CRF and to perform channel estimation using information from the CRF, making synchronization and channel estimation simpler and more efficient. However, existing channel estimation methods using CP data have high requirements for signal quality, such as high signal-to-noise ratio and low delay spread. Summary of the Invention

[0005] This invention provides an interference detection method, apparatus, device, medium, and product for OFDM signals, to solve the problem that existing channel estimation using CP data has high requirements for signal quality and is applicable to a narrow range of interference detection scenarios.

[0006] In a first aspect, embodiments of the present invention provide an interference detection method for OFDM signals, comprising: Receive an OFDM signal to be detected, wherein each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L and a useful symbol of length N, wherein the cyclic prefix is ​​obtained by copying the tail symbol of length L in the useful symbol; Extract the cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data; Determine the second noise power of the OFDM signal to be detected in the frequency domain; The presence of interference in the OFDM signal to be detected is determined based on the first noise power and the second noise power.

[0007] Further, the cyclic prefix data and tail symbol data of the OFDM signal to be detected, with a length of L sampling points, are extracted, including: Move the sliding window and calculate the correlation value between the sampling points within the sliding window and the N sampling points behind the sliding window; the width of the sliding window is L sampling points. When the correlation value is at its peak, the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window are determined as cyclic prefix data; Starting from a position N sampling points away from the beginning of the cyclic prefix data, L sampling points of the OFDM signal to be detected are continuously sampled as tail symbol data.

[0008] Further, determining the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data includes: The difference between the cyclic prefix data and the tail symbol data is determined as the first noise signal; Half of the variance of the first noise signal is determined as the first noise power.

[0009] Furthermore, determining the second noise power of the OFDM signal to be detected in the frequency domain includes: Extract pilot signals from the OFDM signal to be detected; The pilot signal is estimated by least squares, and the estimation result is transformed by IFFT to obtain the time-domain channel impulse response; Determine the power delay spectrum corresponding to the time-domain channel impulse response; Noise path estimation is performed on the power delay spectrum to obtain the time-domain noise power; The time-domain noise power is converted to the frequency domain to obtain the second noise power of the OFDM signal to be detected in the frequency domain.

[0010] Furthermore, determining whether interference exists in the OFDM signal to be detected based on the first noise power and the second noise power includes: Calculate the power difference between the first noise power and the second noise power; If the power difference is greater than or equal to the threshold value, then the OFDM signal to be detected is determined to be subject to interference. If the power difference is less than the threshold value, it is determined that the OFDM signal to be detected is not subject to interference.

[0011] Secondly, embodiments of the present invention provide an interference detection device for OFDM signals, comprising: The signal receiving module is used to receive the OFDM signal to be detected. Each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L sampling points and a useful symbol of length N sampling points. The cyclic prefix is ​​obtained by copying the tail symbol of length L sampling points in the useful symbol. The first noise power estimation module is used to extract the cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and to determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data. The second noise power estimation module is used to determine the second noise power of the OFDM signal to be detected in the frequency domain. An interference detection module is used to determine whether interference exists in the OFDM signal to be detected based on the power difference between the first noise power and the second noise power.

[0012] Furthermore, the first noise power estimation module includes: A window moving unit is used to move a sliding window and calculate the correlation value between the sampling points within the sliding window and N sampling points behind the sliding window; the width of the sliding window is L sampling points. The cyclic prefix data determination unit is used to determine the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window as cyclic prefix data when the correlation value is at its peak. The tail symbol data determination unit is used to continuously sample data from L sampling points of the OFDM signal to be detected, starting from a position N sampling points away from the start position of the cyclic prefix data, as tail symbol data.

[0013] Thirdly, embodiments of the present invention provide an electronic device, the electronic device comprising: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores a computer program that can be executed by the at least one processor, which is then executed by the at least one processor to enable the at least one processor to perform the OFDM signal interference detection method according to any embodiment of the present invention.

[0014] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer instructions, which are used to cause a processor to execute and implement the OFDM signal interference detection method according to any embodiment of the present invention.

[0015] Fifthly, embodiments of the present invention provide a computer program product including a computer program, which, when executed by a processor, implements the OFDM signal interference detection method described in any embodiment of the present invention.

[0016] The technical solution of this invention involves receiving an OFDM signal to be detected. Each OFDM symbol in the signal contains a cyclic prefix of length L and useful symbol data of length N. The cyclic prefix is ​​obtained by copying the tail symbol of length L from the useful symbol. The cyclic prefix data and tail symbol data of length L from the OFDM signal to be detected are extracted, and a first noise power of the OFDM signal in the time domain is determined based on the cyclic prefix data and the tail symbol data. A second noise power of the OFDM signal in the frequency domain is determined. The presence of interference in the OFDM signal is determined based on the first noise power and the second noise power. Utilizing the inherent CP structure of the OFDM signal, interference is detected by the difference between the CP and the tail. This method has low signal quality requirements and does not require prior information such as the type, spectral characteristics, or statistical properties of the interference. It is applicable to various types of interference and does not occupy additional spectrum resources or transmission time. This solves the problem that existing channel estimation methods using CP data have high signal quality requirements and are applicable to a narrow range of interference detection scenarios.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The flowchart shows an OFDM signal interference detection method provided in Embodiment 1 of the present invention. Figure 2 This is a flowchart of an OFDM signal interference detection method provided in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the structure of an OFDM signal interference detection device provided in Embodiment 3 of the present invention; Figure 4A schematic diagram of the structure of an electronic device for implementing the OFDM signal interference detection method of this embodiment of the invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Example 1 Figure 1 This is a flowchart of an OFDM signal interference detection method provided in Embodiment 1 of the present invention. This embodiment is applicable to situations where interference detection of OFDM signals is performed using CP data. The method can be executed by an OFDM signal interference detection device, which can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes: S110. Receive the OFDM signal to be detected. Each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L and a useful symbol of length N. The cyclic prefix data is obtained by copying the tail symbol of length L in the useful symbol.

[0023] Orthogonal Frequency Division Multiplexing (OFDM) is a special multi-carrier modulation technique. It is a communication method that decomposes a high-speed data stream into multiple low-speed data streams, which are then transmitted in parallel on multiple mutually orthogonal subcarriers.

[0024] In this embodiment, the OFDM signal consists of multiple OFDM symbols in the time domain. Each OFDM symbol contains a cyclic prefix (CP) of length L samples and a useful symbol of length N samples. The cyclic prefix is ​​obtained by copying the tail symbol of the useful symbol by L samples; theoretically, the cyclic prefix and the L samples at the tail of the useful symbol are identical at the transmitting end. However, due to the influence of time-varying channels and differences in superimposed interference signals and noise, the CP and tail symbol data will differ at the receiving end.

[0025] Specifically, let X be the time-domain sampling sequence of the useful symbols of an OFDM symbol. ref =[x(0),x(1),…, x(N-1)], with a length of N sampling points; then the cyclic prefix is ​​X. CP =[x(NL),x(N-L+1),…, x(N-1)], with a length of L sampling points. The complete OFDM symbol after adding the cyclic prefix is ​​X=X CP +X ref =[x(NL),…, x(N-1), x(0),x(1),…,x(N-1)], with a length of N+L sampling points.

[0026] S120. Extract the cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and tail symbol data.

[0027] The cyclic prefix data can be considered as the data of the cyclic prefix portion of the OFDM symbol extracted from the OFDM signal to be detected. The tail symbol data can be considered as the time-domain sampling point sequence of the tail of the OFDM symbol extracted from the OFDM signal to be detected. The length of both the tail symbol data and the cyclic prefix data is L sampling points.

[0028] The first noise power can be considered as the estimated noise power in the time domain, which can reflect the degree to which the signal consistency is disrupted within the CP interval. It reflects the background noise power when there is no interference, and the superposition power of noise and interference residue when there is interference.

[0029] In this embodiment, a time-domain sampling point sequence of length L sampling points is extracted from the cyclic prefix portion of the OFDM signal to be detected to obtain the cyclic prefix data x. CP (n); and extract the time-domain sampling point sequence of length L sampling points from the tail of the useful symbol portion of the OFDM signal to be detected, to obtain the tail symbol data x. ref(n). Determine the first noise signal in the time domain based on the cyclic prefix data and the tail symbol data, and calculate the first noise power corresponding to the first noise signal. .

[0030] S130. Determine the second noise power of the OFDM signal to be detected in the frequency domain.

[0031] The second noise power can be considered as the estimated noise power in the frequency domain, which can reflect the noise floor level in the frequency domain. When there is no interference, it reflects the background noise power, and when there is interference, it may increase to different degrees due to the frequency domain characteristics of the interference.

[0032] In this embodiment, the pilot signal of the OFDM signal to be detected is extracted, and frequency domain estimation is performed on the pilot signal to obtain the second noise power of the OFDM signal to be detected in the frequency domain. The pilot signal can be considered as the received signal of the OFDM signal to be detected at the pilot position.

[0033] S140. Determine whether there is interference in the OFDM signal to be detected based on the first noise power and the second noise power.

[0034] In this embodiment, the power difference between the first noise power and the second noise power is calculated, and the power difference is compared with a preset threshold value to determine whether there is interference in the OFDM signal to be detected.

[0035] As an optional embodiment, determining whether interference exists in the OFDM signal to be detected based on the first noise power and the second noise power includes: Calculate the power difference between the first noise power and the second noise power; If the power difference is greater than or equal to the threshold value, then the OFDM signal to be detected is determined to be subject to interference. If the power difference is less than the threshold value, it is determined that the OFDM signal to be detected is not subject to interference.

[0036] The threshold value γ can be preset according to the system's requirements for false alarm probability and detection probability, or it can be dynamically adjusted according to the channel environment. For example, the threshold value γ can be set as a multiple of the standard deviation of the background noise power estimation error, or it can be determined through simulation and actual measurement.

[0037] Specifically, under interference-free conditions, the first noise power Second noise power Both reflect background noise power, and their theoretical values ​​are equal, with the power difference close to zero (only estimation error exists). In the presence of interference, the interfering signal disrupts the consistency between the cyclic prefix and tail data, leading to an increase in the first noise power. The noise power increases significantly; while interference may be averaged or suppressed in the frequency domain, resulting in a second noise power. The increase is relatively small. Therefore, by comparing the difference between the two and comparing it with the threshold, the presence of interference can be accurately determined.

[0038] The technical solution of this invention involves receiving an OFDM signal to be detected. Each OFDM symbol in the signal contains a cyclic prefix of length L and useful symbol data of length N. The cyclic prefix is ​​obtained by copying the tail symbol of length L from the useful symbol. The cyclic prefix data and tail symbol data of length L from the OFDM signal to be detected are extracted, and a first noise power in the time domain of the OFDM signal to be detected is determined based on the cyclic prefix data and tail symbol data. A second noise power in the frequency domain of the OFDM signal to be detected is determined. The presence of interference in the OFDM signal to be detected is determined based on the first noise power and the second noise power. Utilizing the inherent CP structure of the OFDM signal, interference is detected by the difference between the CP and the tail. This method has low requirements for signal quality and does not require any prior information such as the type, spectral characteristics, or statistical properties of the interference. It is applicable to various types of interference and does not occupy additional spectrum resources or transmission time.

[0039] Example 2 Figure 2 This is a flowchart of an OFDM signal interference detection method according to Embodiment 2 of the present invention. Based on the above embodiments, this embodiment refines the specific steps for detecting the first noise power of the OFDM signal in the time domain. Specifically, extracting cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points includes: moving a sliding window and calculating the correlation value between the sampling points within the sliding window and N sampling points following the sliding window; the width of the sliding window is L sampling points; when the correlation value reaches its peak, determining the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window as cyclic prefix data; starting from a position N sampling points away from the starting position of the cyclic prefix data, continuously sampling the data of the OFDM signal to be detected for L sampling points as tail symbol data.

[0040] like Figure 2 As shown, the method includes: S210. Receive the OFDM signal to be detected. Each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L and a useful symbol of length N. The cyclic prefix is ​​obtained by copying the tail symbol of length L in the useful symbol.

[0041] S220. Move the sliding window and calculate the correlation value between the sampling points in the sliding window and the N sampling points behind the sliding window; the width of the sliding window is L sampling points.

[0042] In this embodiment, a sliding window with a width of L sampling points is set on the received continuous time-domain signal. The sliding window moves point by point on the signal (moving 1 sampling point at a time), and the position of each sliding window represents the starting position of a candidate symbol. For the position of each sliding window... Calculate the correlation values ​​between the L sampling points within the sliding window and the N sampling points after the sliding window. ,Right now: ; in, Indicates taking the conjugate; This represents the L sampling points within the window. This represents the L sampling points starting from the window's initial position, offset N sampling points backward.

[0043] S230. When the correlation value is at its peak, the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window are determined as the cyclic prefix data.

[0044] In this embodiment, when the sliding window moves to make the relevant value The position where the maximum value is reached is the starting position of the current OFDM symbol. The peak value of the OFDM signal to be detected is measured at L sampling points (i.e., the starting positions) within the sliding window. The initial L sampling points are determined to be cyclic prefix data, which can be represented as: .

[0045] S240. Starting from a position N sampling points away from the start of the cyclic prefix data, continuously sample L sampling points of the OFDM signal to be detected as tail symbol data.

[0046] In this embodiment, once the starting position of the cyclic prefix data is determined... The starting position of the tail symbol data is uniquely determined. Then the tail sign data can be represented as: .

[0047] S250. The first noise power is determined based on the cyclic prefix data and the tail symbol data according to the time domain estimation.

[0048] As an optional embodiment, determining the first noise power in the time domain based on the cyclic prefix data and the tail symbol data includes: The difference between the cyclic prefix data and the tail symbol data is determined as the first noise signal; Half of the variance of the first noise signal is determined as the first noise power.

[0049] Specifically, in the absence of interference, the first noise signal can be represented as: Alternatively, in the presence of interference, the first noise signal can be expressed as: By analyzing the first noise signal or Calculate the variance to obtain the first noise power. ,Right now ,or .

[0050] S260. Determine the second noise power of the OFDM signal to be detected in the frequency domain.

[0051] As an optional embodiment, determining the second noise power of the OFDM signal to be detected in the frequency domain includes: A1. Extract pilot signals from the OFDM signal to be detected.

[0052] Specifically, the pilot signal Y corresponding to the pilot position is extracted from the OFDM symbols contained in the received OFDM signal to be detected. pilot (k).

[0053] A2. Perform least squares estimation on the pilot signal and then perform IFFT transformation on the estimation result to obtain the time-domain channel impulse response.

[0054] In this embodiment, the pilot signal Y pilot (k) The least squares (LS) estimation is performed to obtain the estimation result. Optionally, the estimation results will be... Extended to the entire FFT length N FFT Furthermore, the non-pilot positions are set to zero, ensuring a uniform distribution of time-domain noise after subsequent IFFTs and preserving the statistical characteristics of the noise, for example: ; in, To extend to the entire FFT length N FFT The estimation results This is the set of pilot subcarrier indices.

[0055] Then, the estimation results Or extended to Perform an IFFT transform to obtain the time-domain channel impulse response. , It includes real channel impulse response and noise.

[0056] A3. Determine the power delay spectrum corresponding to the time-domain channel impulse response.

[0057] Specifically, the power delay spectrum corresponding to the time-domain channel impulse response is determined as follows: PDP reflects the signal power distribution at different time delay locations.

[0058] A4. Perform noise path estimation on the power delay spectrum to obtain the time-domain noise power.

[0059] Specifically, a fixed threshold or an adaptive threshold (such as a preset multiple of the average power) is used to determine the effective signal path range, the signal window is determined based on the length of the CP, and the noise window includes all points outside the signal path range. The time-domain noise power is obtained by averaging the PDP values ​​within the noise window. : .

[0060] A5. Perform frequency domain conversion on the time domain noise power to obtain the second noise power of the OFDM signal to be detected in the frequency domain.

[0061] Specifically, based on Parseval's theorem and the unitary transform property of IFFT, the time-domain noise power is converted into a second noise power in the frequency domain, i.e. .

[0062] Since the LS estimate only has a value at the pilot position, the second noise power in the frequency domain can be corrected as follows: ; in, This represents the number of pilot subcarriers.

[0063] S270. Determine whether there is interference in the OFDM signal to be detected based on the first noise power and the second noise power.

[0064] The technical solution of this invention involves receiving an OFDM signal to be detected. Each OFDM symbol in the OFDM signal contains a cyclic prefix of length L sampling points and a useful symbol of length N sampling points. The cyclic prefix is ​​obtained by copying the tail symbol of length L sampling points from the useful symbol. A sliding window is moved, and the correlation value between the sampling points within the sliding window and the N sampling points behind the sliding window is calculated. The width of the sliding window is L sampling points. When the correlation value reaches its peak, the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window is determined as the cyclic prefix data. Starting from a position N sampling points away from the start position of the cyclic prefix data, the data of the L sampling points of the OFDM signal to be detected are continuously sampled as the tail symbol data. A first noise power of the OFDM signal to be detected in the time domain is determined based on the cyclic prefix data and the tail symbol data. A second noise power of the OFDM signal to be detected in the frequency domain is determined. The presence of interference in the OFDM signal to be detected is determined based on the first noise power and the second noise power. By utilizing the inherent CP structure of OFDM signals, interference can be detected through the difference between the CP and the tail. This method has low requirements for signal quality and does not require any prior information such as the type, spectral characteristics, or statistical properties of the interference. It can detect the presence of interference, is applicable to various types of interference, and does not occupy additional spectrum resources or transmission time.

[0065] Example 3 Figure 3 This is a schematic diagram of an OFDM signal interference detection device provided in Embodiment 3 of the present invention. Figure 3 As shown, the device includes: a signal receiving module 310, a first noise power estimation module 320, a second noise power estimation module 330, and an interference detection module 340; wherein: Signal receiving module 310 is used to receive an OFDM signal to be detected, wherein each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L sampling points and a useful symbol of length N sampling points, and the cyclic prefix is ​​obtained by copying the tail symbol of length L sampling points in the useful symbol; The first noise power estimation module 320 is used to extract cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and to determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data. The second noise power estimation module 330 is used to determine the second noise power of the OFDM signal to be detected in the frequency domain. Interference detection module 340 is used to determine whether there is interference in the OFDM signal to be detected based on the power difference between the first noise power and the second noise power.

[0066] This invention provides an interference detection device for OFDM signals. It receives an OFDM signal to be detected. Each OFDM symbol in the signal contains a cyclic prefix of length L samples and useful symbol data of length N samples. The cyclic prefix is ​​obtained by copying the tail symbol of length L samples from the useful symbol. The cyclic prefix data and tail symbol data of length L samples from the OFDM signal to be detected are extracted. A first noise power in the time domain of the OFDM signal to be detected is determined based on the cyclic prefix data and tail symbol data. A second noise power in the frequency domain of the OFDM signal to be detected is determined. The presence of interference in the OFDM signal to be detected is determined based on the first noise power and the second noise power. Utilizing the inherent CP structure of OFDM signals, interference is detected by the difference between the CP and the tail. This method has low requirements for signal quality and does not require prior information such as the type, spectral characteristics, or statistical properties of the interference. It is applicable to various types of interference and does not occupy additional spectrum resources or transmission time.

[0067] Optionally, the first noise power estimation module 320 includes: A window moving unit is used to move a sliding window and calculate the correlation value between the sampling points within the sliding window and N sampling points behind the sliding window; the width of the sliding window is L sampling points. The cyclic prefix data determination unit is used to determine the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window as cyclic prefix data when the correlation value is at its peak. The tail symbol data determination unit is used to continuously sample data from L sampling points of the OFDM signal to be detected, starting from a position N sampling points away from the start position of the cyclic prefix data, as tail symbol data.

[0068] Optionally, the first noise power estimation module 320 includes: The first noise signal determination unit is used to determine the difference between the cyclic prefix data and the tail symbol data as the first noise signal; The first noise power determination unit is used to determine half of the variance of the first noise signal as the first noise power.

[0069] Optionally, the second noise power estimation module 330 is specifically used for: Extract pilot signals from the OFDM signal to be detected; The pilot signal is estimated by least squares, and the estimation result is transformed by IFFT to obtain the time-domain channel impulse response; Determine the power delay spectrum corresponding to the time-domain channel impulse response; Noise path estimation is performed on the power delay spectrum to obtain the time-domain noise power; The time-domain noise power is converted to the frequency domain to obtain the second noise power of the OFDM signal to be detected in the frequency domain.

[0070] Optionally, the interference detection module 340 is specifically used for: Calculate the power difference between the first noise power and the second noise power; If the power difference is greater than or equal to the threshold value, then the OFDM signal to be detected is determined to be subject to interference. If the power difference is less than the threshold value, it is determined that the OFDM signal to be detected is not subject to interference.

[0071] The OFDM signal interference detection device provided in this embodiment of the invention can execute the OFDM signal interference detection method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0072] Example 4 Figure 4 A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0073] like Figure 4 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0074] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0075] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as interference detection methods for OFDM signals.

[0076] In some embodiments, the OFDM signal interference detection method can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the OFDM signal interference detection method described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the OFDM signal interference detection method by any other suitable means (e.g., by means of firmware).

[0077] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0078] In some embodiments, the OFDM signal interference detection method can be implemented as a computer program, which is implicitly included in a computer program product. When executed by a processor, the computer program implements the OFDM signal interference detection method of the present invention. The computer program product can be understood as a software product that primarily implements its solution through a computer program. The computer program used to implement the method of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program can be executed entirely on a machine, partially on a machine, partially on a remote machine as a standalone software package, or entirely on a remote machine or server.

[0079] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0080] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0081] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0082] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0083] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0084] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for detecting interference in OFDM signals, characterized in that, include: Receive an OFDM signal to be detected, wherein each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L and a useful symbol of length N, wherein the cyclic prefix is ​​obtained by copying the tail symbol of length L in the useful symbol; Extract the cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data; Determine the second noise power of the OFDM signal to be detected in the frequency domain; The presence of interference in the OFDM signal to be detected is determined based on the first noise power and the second noise power.

2. The method according to claim 1, characterized in that, Extracting the cyclic prefix data and tail symbol data of the OFDM signal to be detected, with a length of L sampling points, includes: Move the sliding window and calculate the correlation value between the sampling points within the sliding window and the N sampling points behind the sliding window; the width of the sliding window is L sampling points; When the correlation value is at its peak, the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window are determined as cyclic prefix data; Starting from a position N sampling points away from the beginning of the cyclic prefix data, L sampling points of the OFDM signal to be detected are continuously sampled as tail symbol data.

3. The method according to claim 2, characterized in that, The step of determining the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data includes: The difference between the cyclic prefix data and the tail symbol data is determined as the first noise signal; Half of the variance of the first noise signal is determined as the first noise power.

4. The method according to any one of claims 1-3, characterized in that, Determining the second noise power of the OFDM signal to be detected in the frequency domain includes: Extract pilot signals from the OFDM signal to be detected; The pilot signal is estimated by least squares, and the estimation result is transformed by IFFT to obtain the time-domain channel impulse response; Determine the power delay spectrum corresponding to the time-domain channel impulse response; Noise path estimation is performed on the power delay spectrum to obtain the time-domain noise power; The time-domain noise power is converted to the frequency domain to obtain the second noise power of the OFDM signal to be detected in the frequency domain.

5. The method according to claim 1, characterized in that, The step of determining whether the OFDM signal to be detected is subject to interference based on the first noise power and the second noise power includes: Calculate the power difference between the first noise power and the second noise power; If the power difference is greater than or equal to the threshold value, then the OFDM signal to be detected is determined to be subject to interference. If the power difference is less than the threshold value, it is determined that the OFDM signal to be detected is not subject to interference.

6. An interference detection device for OFDM signals, characterized in that, include: The signal receiving module is used to receive the OFDM signal to be detected. Each OFDM symbol in the OFDM signal to be detected contains a cyclic prefix of length L sampling points and a useful symbol of length N sampling points. The cyclic prefix is ​​obtained by copying the tail symbol of length L sampling points in the useful symbol. The first noise power estimation module is used to extract cyclic prefix data and tail symbol data of the OFDM signal to be detected with a length of L sampling points, and to determine the first noise power of the OFDM signal to be detected in the time domain based on the cyclic prefix data and the tail symbol data. The second noise power estimation module is used to determine the second noise power of the OFDM signal to be detected in the frequency domain. An interference detection module is used to determine whether interference exists in the OFDM signal to be detected based on the power difference between the first noise power and the second noise power.

7. The apparatus according to claim 6, characterized in that, The first noise power estimation module includes: A window moving unit is used to move a sliding window and calculate the correlation value between the sampling points within the sliding window and N sampling points behind the sliding window; the width of the sliding window is L sampling points. The cyclic prefix data determination unit is used to determine the data corresponding to the L sampling points of the OFDM signal to be detected within the sliding window as cyclic prefix data when the correlation value is at its peak. The tail symbol data determination unit is used to continuously sample L sampling points of the OFDM signal to be detected, starting from a position N sampling points away from the start position of the cyclic prefix data, as tail symbol data.

8. An electronic device, characterized in that, The electronic device includes: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores a computer program that can be executed by the at least one processor, which is then executed by the at least one processor to enable the at least one processor to perform the interference detection method for OFDM signals according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the interference detection method for OFDM signals according to any one of claims 1-6.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the interference detection method for OFDM signals according to any one of claims 1-6.

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