Received signal processing method and device, method for realizing AoA estimation and UWB equipment

Abstract

The invention discloses a received signal processing method and device, a method for realizing AoA estimation and UWB equipment, and the method comprises the steps: employing a received signal obtained through low-intermediate frequency receiving, eliminating the phase change introduced by intermediate frequency offset in the received signal, and carrying out the AoA estimation of the received signal; and accumulation processing is carried out on the received signal of which the phase change introduced by the intermediate frequency offset in the received signal is eliminated, so that the influence of IQ imbalance in the received signal is effectively suppressed by an obtained signal accumulation result, and the capability of suppressing a mirror image frequency signal by a system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to, but is not limited to, communication technology, and in particular to a signal receiving processing method and device, an AoA estimation method and a UWB device. BACKGROUND

[0002] Ultra-Wideband (UWB) technology is a wireless carrier communication technology that uses nanoscale non-sine narrow wave pulse signals for data transmission. Because the transmitted signal bandwidth is very wide, it can cover a frequency band of several gigahertz, so it is called ultra-wideband technology. UWB positioning is a technology that uses ultra-short pulse signals for high-precision positioning. The Angle of Arrival (AoA) algorithm is a commonly used method in UWB positioning, which is used to determine the angle of the target object relative to the receiver. The estimation accuracy of AoA directly affects the accuracy of the target object position determination.

[0003] In a UWB system, a zero intermediate frequency receiver is usually used to receive a signal with a specified center frequency point, and subsequent processing is performed at the baseband after down-conversion. The working principle of the zero intermediate frequency receiver received includes: first, after the antenna of the receiving end receives a wideband radio frequency signal, a radio frequency filter is used to select the frequency band of interest to suppress unwanted interference and noise; then, the filtered radio frequency signal is directly down-converted to the baseband using a local oscillator (LO), and because the LO frequency used by the zero intermediate frequency receiver is the same as the center frequency of the received signal, the down-converted signal spectrum is concentrated around 0 Hz; then, IQ demodulation is performed, and the in-phase component (I component) and the quadrature component (Q component) are obtained by mixing the LO signal and the 90-degree phase-shifted LO signal through a mixer; then, the I component and the Q component are low-pass filtered to remove high-frequency components to obtain a baseband signal; finally, the analog signals of the I component and the Q component are converted into digital signals for subsequent digital signal processing.

[0004] Due to the imperfect matching of the device characteristics of the IQ two branches, such as: the IQ characteristics of the LO are not completely balanced, the frequency responses of the low-pass filters of the IQ two branches are not completely matched, etc., the phases and amplitudes of the IQ two phases are usually not completely the same, resulting in the problem of IQ imbalance (or mismatch).

[0005] IQ imbalance can cause distortion of the signal, and AoA estimation depends on the phase and amplitude information of the received signal, that is, the signal distortion introduced by IQ imbalance will affect the accuracy of AoA estimation, and cause an error floor in AoA estimation, and the reduction of the accuracy of AoA estimation will directly reduce the accuracy of the target object position determination and the system performance. SUMMARY

[0006] The application provides a signal receiving processing method and device, an AoA estimation method and a UWB device, which can suppress the influence of IQ imbalance in a received signal.

[0007] The application provides a signal receiving processing method, which is applied to a receiving end of a UWB system, and includes the following steps: the receiving end uses a low intermediate frequency to receive a signal to obtain a received signal, wherein an intermediate frequency offset exists between the intermediate frequency used by the receiving end and the intermediate frequency used by a transmitting end; the received signal is processed to eliminate a phase change in the received signal caused by the intermediate frequency offset; and the processed received signal is subjected to accumulation operation.

[0008] In an example, the receiving end uses multiple antennas to receive a signal.

[0009] In an example, the processing of the received signal to eliminate the phase change in the received signal caused by the intermediate frequency offset includes processing the received signal according to a predefined phase term to eliminate the phase change in the received signal caused by the intermediate frequency offset.

[0010] In an example, the predefined phase term is determined based on a phase of a transmitted signal, a frequency difference between intermediate frequencies of the transmitting end and the receiving end, and a sampling frequency. For example, the predefined phase term can be: wherein θ gt represents the phase of the transmitted signal; represents the phase change caused by the intermediate frequency offset; f o represents the frequency difference between the intermediate frequencies of the transmitting end and the receiving end; f s represents the sampling frequency, and t represents a time variable.

[0011] In an example, the processing of the received signal according to the predefined phase term includes that the received signal is subjected to a multiplication operation based on the predefined phase term to eliminate the phase change in the received signal caused by the intermediate frequency offset. For example, the received signal can be multiplied by the predefined phase term to eliminate the phase change.

[0012] In an example, the accumulation operation of the processed received signal can include that the received signal from which the phase change caused by the intermediate frequency offset is eliminated is subjected to summation and conjugate multiplication calculation to obtain an accumulation result of the received signal.

[0013] In an example, the receiving end uses two antennas to receive a signal; and the accumulated received signal model can be represented as:

[0014]

[0015] wherein, is a coefficient related to gain and phase imbalance, cosβ+j sinβ is a term related to signal phase; g is an IQ amplitude imbalance parameter; β=2πdsin(α) represents a phase difference based on an angle of arrival α.

[0016] In an exemplary instance, in the UWB system, a binary phase shift keying (BPSK) signal is used for transmission.

[0017] The embodiments of the present application further provide a method for implementing AoA estimation, comprising the receiving signal processing method described in any of the above embodiments; and further comprising: obtaining an angle of arrival based on the accumulated processed signal.

[0018] In an exemplary instance, the obtaining of the angle of arrival based on the accumulated processed signal comprises: extracting a phase difference β based on the real part and the imaginary part of the accumulated processed signal; and calculating the angle of arrival α of the received signal based on the extracted phase difference β and antenna parameters.

[0019] In an exemplary instance, the angle of arrival α is calculated according to the following formula: wherein, λ represents the wavelength of the signal, and d represents the distance between the receiving antennas.

[0020] The embodiments of the present application further provide a method for implementing AoA estimation, which can comprise: implementing a low intermediate frequency received signal by adjusting a digital mixer to a zero frequency at a receiving end; eliminating signal distortion caused by IQ imbalance in a UWB system based on the low intermediate frequency received signal; and obtaining an angle of arrival based on the signal after elimination of the signal distortion.

[0021] In an exemplary instance, the receiving signal processing method described in any of the embodiments of the present application can be used to eliminate signal distortion caused by IQ imbalance in the UWB system.

[0022] In an exemplary instance, the obtaining of the angle of arrival based on the signal after elimination of the signal distortion can comprise: obtaining the angle of arrival based on an accumulated processed signal; wherein the length of a preamble of a synchronization segment sync in the accumulated processed signal is greater than 16 symbols.

[0023] The embodiments of the present application further provide a computer readable storage medium storing computer executable instructions, which are used for the receiving signal processing method described in any of the above embodiments, and / or the method for implementing AoA estimation described in any of the above embodiments.

[0024] The embodiment of the present application further provides a computer device comprising a memory and a processor, wherein the memory stores instructions executable by the processor, the instructions being used for performing the steps of the receiving signal processing method in any of the preceding embodiments, and / or the steps of the method for implementing AoA estimation in any of the preceding embodiments.

[0025] The embodiment of the present application further provides a receiving signal processing apparatus comprising a receiving module, a processing module, a calculating module and an obtaining module, wherein the receiving module is configured to obtain a receiving signal by using a low intermediate frequency for signal receiving, and an intermediate frequency offset exists between the intermediate frequency used by a receiving end and the intermediate frequency used by a transmitting end; the processing module is configured to process the receiving signal to eliminate phase variation in the receiving signal caused by the intermediate frequency offset; and the calculating module is configured to perform accumulation operation on the processed receiving signal.

[0026] In an example, the processing module is configured to process the receiving signal according to a predefined phase term to eliminate the phase variation in the receiving signal caused by the intermediate frequency offset.

[0027] In an example, the calculating module is configured to perform summation and conjugate multiplication calculation on the receiving signal from which the phase variation caused by the intermediate frequency offset is eliminated, to obtain the accumulated receiving signal.

[0028] The embodiment of the present application further provides a UWB device comprising the receiving signal processing apparatus in any of the preceding embodiments.

[0029] The embodiment of the present application further provides an apparatus for implementing AoA estimation, comprising the receiving signal processing apparatus in any of the preceding embodiments, and further comprising an obtaining module configured to obtain an angle of arrival according to the accumulated processed signal.

[0030] In an example, the obtaining module is configured to extract a phase difference β according to a real part and an imaginary part of the accumulated processed receiving signal, and calculate the angle of arrival α of the receiving signal by using the extracted phase difference β and an antenna parameter.

[0031] The embodiment of the present application further provides a UWB device, which can comprise a transmitting end configured to transmit a signal by using a first intermediate frequency, a receiving end configured to receive a signal by using a second intermediate frequency to implement low intermediate frequency communication signal receiving, the second intermediate frequency having an intermediate frequency offset relative to the first intermediate frequency, and a processor configured to suppress signal distortion caused by IQ imbalance based on the intermediate frequency offset.

[0032] In an example, the processor is configured to suppress the signal distortion caused by the IQ imbalance by using the receiving signal processing method in any of the embodiments of the present application.

[0033] The receiving signal processing method provided in the embodiment of the present application uses the received signal obtained by low intermediate frequency receiving, eliminates the phase change caused by intermediate frequency offset in the received signal, and then performs accumulation processing on the received signal from which the phase change caused by intermediate frequency offset is eliminated, so that the influence of IQ imbalance in the received signal is effectively suppressed, and the ability of the system to suppress image frequency signals is improved.

[0034] The method for implementing AoA estimation provided in the embodiment of the present application effectively suppresses the influence of IQ imbalance in the received signal by using the low intermediate frequency receiving method, thereby improving the estimation accuracy of AoA in UWB, especially in the case where IQ imbalance is not calibrated or the IQ imbalance calibration result is poor, the influence of IQ imbalance on the accuracy of AoA estimation is greatly suppressed, and a good AoA estimation result is obtained, so that the arrival angle is accurately calculated even in the case where IQ imbalance exists, thereby improving the accuracy of target object position determination and the system performance.

[0035] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings are included to provide a further understanding of the technical scheme of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical scheme of the present application, and do not constitute a limitation on the technical scheme of the present application.

[0037] Figure 1 Error floor experiment display diagram for angle error of AoA estimation in the related art;

[0038] Figure 2 Flowchart of the receiving signal processing method in the embodiment of the present application;

[0039] Figure 3 Flowchart of the method for implementing AoA estimation in the embodiment of the present application;

[0040] Figure 4 Error floor experiment display diagram for angle error of AoA estimation in the embodiment of the present application;

[0041] Figure 5 Structural schematic diagram of the receiving signal processing device in the embodiment of the present application;

[0042] Figure 6 Structural schematic diagram of the device for implementing AoA estimation in the embodiment of the present application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0044] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0046] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0048] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0049] IQ imbalance signifies an imbalance in amplitude and phase: amplitude imbalance means the gains of the I and Q channels are inconsistent, resulting in different amplitudes of the two signals; phase imbalance means the phase difference between the I and Q channels is not equal to 90 degrees, violating orthogonality. Accurate AoA estimation relies on the integrity of the received signal. Errors introduced by IQ imbalance degrade the performance of the AoA algorithm. For example, signal distortion leads to incorrect angle estimation, thus reducing the accuracy of AoA estimation. Furthermore, additional noise introduced by mirror signal interference increases noise levels, further affecting the accuracy of AoA estimation.

[0050] Image rejection ratio (IRR) is the ratio of the desired signal power to the image signal power, usually expressed in decibels (dB). IRR quantifies the system's ability to suppress image frequency signals, i.e., the redundant image signals caused by IQ channel imbalance. For signal distortion caused by IQ imbalance, IQ calibration methods are mostly used to achieve a high IRR after calibration, minimizing the impact of IQ imbalance on the estimation accuracy of AOA. However, UWB systems only have one (I-channel) digital-to-analog converter (DAC) at the transmitter. Therefore, IQ calibration requires additional hardware circuitry, such as a local oscillator phase shifter (LO phase shifter) or a phase-locked loop (PLL). Because UWB has a wide bandwidth (499.2MHz~1354.97MHz), the IQ imbalance coefficient is frequency-dependent. In order to better compensate for frequency-dependent IQ imbalance (FD IQ mismatch, Frequency-Dependent IQ mismatch), a higher-order complex filter is usually required, which undoubtedly increases the complexity of the system.

[0051] In UWB systems, binary phase-shift keying (BPSK) signals are used for transmission. The signal at the transmitting end (Tx end) consists of a series of non-zero elements used for AoA estimation. Specifically, for a given transmitted signal g... tx Two receiving antennas are used at the receiving end to receive signals, and AoA is calculated based on the received signals.

[0052] The BPSK signal at the Tx terminal of UWB has only non-zero elements that can be used to estimate AoA, as shown in formula (1). The transmitted signal g tx It is a vector consisting of +1 and -1:

[0053] g tx ={+1,-1,-1,+1,+1,-1,…}∈{+1,-1} T (1)

[0054] At the receiving end (Rx end), in some traditional zero-IF receiving schemes, two receiving antennas can be used to receive the transmitted signal g. tx The signals received by the two antennas are shown in formulas (2) and (3), respectively:

[0055] y 01 =A1g tx e jθ (2)

[0056] y 02 =A2g tx e jθ e j2πdsin(α) (3)

[0057] Where A1 and A2 represent the amplitudes of the signals received by the two antennas, θ represents the LO phase difference between the transmitter and receiver, d represents the distance between the receiving antennas (in wavelength), and α represents the AoA to be estimated.

[0058] Ideally, the conjugate product of the received signals is as shown in equation (4):

[0059]

[0060] Due to the transmitted signal g tx Each element is ±1, and its modulus squared |g tx | 2 It is a constant. By summing over all elements, it can be simplified to a scalar β. The angle of arrival α can be calculated by determining the phase angle of the scalar β: ∠β=2πdsin(α). In other words, ideally, for the received signal y... 01 and received signal y 02 Perform conjugate products, then sum all conjugate products to obtain the scalar β. Calculate the phase angle ∠β of the scalar β, and finally obtain the final AoA estimate α according to formula (5):

[0061]

[0062] In the presence of IQ imbalance, the gain mismatch factor g represents the gain imbalance of the IQ channels, and the phase mismatch angle represents the phase imbalance of the IQ channels. This will cause the original IQ signal to change, as shown in formula (6):

[0063]

[0064] At this point, after correcting the received signal, the signals received by the two antennas are as shown in formulas (7) and (8), respectively:

[0065]

[0066] The calculation of AoA in the presence of IQ imbalance is shown in formula (9):

[0067]

[0068] By simplifying and analyzing formula (9), we can obtain the estimated value α of AoA as shown in formula (10):

[0069]

[0070] Generally, it is assumed that the IQ imbalance coefficient g→1 and φ→0, so formula (10) can be approximated as (defining Δg=g-1) formula (11) is shown:

[0071]

[0072] It can be adopted Describe the impact of IQ imbalance (gain imbalance and phase imbalance) on the received signal, especially its impact when calculating the angle of arrival α. Here, β represents the original signal phase. ′ This represents the distorted phase caused by IQ imbalance, and Δg represents gain imbalance, i.e., the gains of the I channel and the Q channel are inconsistent. This indicates a phase imbalance, meaning the I and Q channels are out of phase. cotβ ′ cotβ represents the cotangent value of the distorted signal; cotβ represents the cotangent value of the original signal. The effect of gain imbalance Δg on signal phase β is described. Specifically, cos(2θ+β) combined with sinβ represents the modulation effect in phase angle, amplifying the effect of gain imbalance on phase. Describes the situation due to phase imbalance The effect on the signal phase β, specifically, sin(2θ+β) combined with sinβ represents the modulation effect on the phase angle, amplifying the influence of phase imbalance on the phase.

[0073] As can be seen from the above formula, the estimated angle error has an error floor, and this error floor is related to the phase difference θ of the LO, and cannot be compensated by post-compensation β. ′ Lower the error threshold. For example, given an IQ imbalance parameter such as g = 1.1, Under the following conditions, such as Figure 1 As shown, the maximum lower bound of the error of AoA estimation in the range θ∈[0,2π) exceeds 3°. Figure 1The horizontal axis represents the trial number, and the vertical axis represents the error (angle) in the estimated angle of arrival α.

[0074] As the above analysis shows, using a traditional zero-IF receiving scheme, the impact of IQ imbalance on the received signal is not negligible, introducing an error related to the LO phase difference θ, which limits the accuracy of AoA estimation. Although approximation and compensation can partially reduce the error, the error floor still exists and cannot be completely eliminated. Therefore, when designing and implementing a UWB system, special attention needs to be paid to the impact of IQ imbalance on system performance, and measures should be taken to minimize its impact as much as possible. To this end, embodiments of this application provide a method and apparatus for AoA estimation, which can suppress the impact of IQ imbalance on the accuracy of AoA estimation, thereby improving the accuracy of target object position determination and system performance.

[0075] Figure 2 This is a flowchart illustrating the signal processing method in an embodiment of this application, applied to the receiver of a UWB system, such as... Figure 2 As shown, it may include:

[0076] Step 200: The receiver uses low-intermediate frequency to receive the signal and obtain the received signal.

[0077] In one exemplary instance, the receiver may employ multiple antennas to receive the transmitted signal. For example, two receiving antennas may be used to receive the transmitted signal g. tx The received signals y1(t) and y2(t) received by the two antennas are shown in Equations (12) and (13), respectively:

[0078]

[0079] Among them, g tx (t) represents the signal envelope at the transmitting end; f o This indicates the difference frequency between the intermediate frequencies (IFs) used by the transmitter and receiver, specifically the IF offset between the IF used by the receiver and the IF used by the transmitter. For example, if the transmitter uses IF f to transmit a signal, then the receiver uses IF f+f. o Receive signal; f s θ represents the sampling frequency; θ represents the initial phase of the received signal. This represents the phase change introduced by the intermediate frequency offset; d represents the distance between the receiving antennas, which determines the phase difference when the signal arrives at different antennas; α represents the AoA to be estimated; e j2πdsin(α) This represents the phase difference caused by the distance d between the antennas and the incident angle α.

[0080] In some embodiments, BPSK signals can be used for transmission in a UWB system. In other embodiments, the link can also use other signal formats for transmission and reception, as long as the receiving end uses a low-IF frequency to receive the transmitted signal to obtain the received signal.

[0081] Step 201: Process the received signal to eliminate the phase change in the received signal caused by the intermediate frequency offset.

[0082] In one exemplary instance, step 201 may include:

[0083] The received signal is processed according to a predefined phase term to eliminate phase changes in the received signal caused by intermediate frequency offset.

[0084] In one embodiment, the predefined phase term can be confirmed based on the phase of the transmitted signal, the frequency difference between the intermediate frequencies at the transmitting and receiving ends, and the sampling frequency. The transmitted signal g is still received using two receiving antennas. tx For example, the received signal can be multiplied by a predefined phase term. To eliminate the phase change in the received signal caused by intermediate frequency offset, θ gt Indicates the phase of the transmitted signal. The received signal can be multiplied based on a predefined phase term to eliminate the phase change introduced by the intermediate frequency offset in the received signal. The calculation can be shown in formulas (14) and (15):

[0085]

[0086] In one exemplary instance, for the case of introducing IQ imbalance, the definition is... Define β = 2πdsin(α), then the received signal after eliminating the frequency offset in step 201 can be expressed as shown in formulas (16) and (17):

[0087]

[0088] In formulas (16) and (17), the symbol ∝ signifies "proportional" or "directly proportional to". The symbol ∝ is used to indicate that one quantity changes proportionally to another. For example, A∝B means that there exists a constant k such that A = kB.

[0089] Where, θ t It is a composite phase term, representing the phase information accumulated during the transmission and reception of signals. θ t This can be represented as shown in formula (14):

[0090]

[0091] In formula (18), θ gt Indicates the phase of the transmitted signal. This represents the phase change introduced by the intermediate frequency offset; θ represents the initial phase of the received signal. The defined phase term θ t Including the first phase term And the second phase term θ.

[0092] Step 202: Perform cumulative calculation on the processed received signal.

[0093] In one exemplary instance, step 202 may include:

[0094] The received signal, after eliminating the phase change introduced by the intermediate frequency offset, is summed and its conjugate product is calculated to obtain the cumulative result of the received signal.

[0095] In one embodiment, two receiving antennas are still used to receive the transmitted signal g. tx For example, the summation of the processed received signals can be performed as shown in formulas (19) and (20):

[0096]

[0097] In one embodiment, the received signal after summation is subjected to a conjugate product operation to obtain the AoA estimate of the signal.

[0098] In one embodiment, combining formulas (14), (15), (19), and (20), the process of conjugate product operation can be expressed as follows:

[0099]

[0100] Assuming the signal length is long enough that higher-order infinitesimal terms can be ignored, that is, terms affected by low-to-intermediate frequencies (such as...) All terms are considered as higher-order infinitesimals of terms unaffected by low-to-mid-frequency factors (such as ∑cos(θ+β)), thus simplifying the expression for the conjugate product operation to the form shown in formula (21):

[0101]

[0102] in, These are coefficients related to gain and phase imbalance; cosβ+j sinβ is a term related to signal phase; g is the IQ amplitude imbalance parameter. It can be seen that by using a low-IF frequency to receive the transmitted signal, and given a sufficiently long data packet, the effects of IQ imbalance can theoretically be completely eliminated through accumulation processing.

[0103] The received signal processing method provided in this application uses a low-IF received signal to eliminate the phase change introduced by the IF offset in the received signal, and then performs accumulation processing on the received signal after eliminating the phase change introduced by the IF offset in the received signal. The resulting signal effectively suppresses the influence of IQ imbalance in the received signal and improves the system's ability to suppress image frequency signals.

[0104] In one embodiment, by accumulating the received signal after eliminating phase changes introduced by intermediate frequency offset, the longer the data accumulation length, the better the suppression effect on IQ imbalance in the received signal. For example, for the length of the sync segment preamble in the data, 16 or more symbols can be accumulated, and the maximum accumulation length can be 4096 symbols. For example, it can be 16, 128, 512, 1024, 1536, 2048, or 4096 symbols.

[0105] In practical engineering implementation, a longer preamble results in a lower error floor. For example, the length of the preamble can be set based on the accuracy requirements, such as those for AOA (Abstract Optical Anomaly). That is, the higher the accuracy requirement, the longer the preamble. However, for scenarios with lower accuracy requirements, the preamble length can be set to 16 symbols.

[0106] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the received signal processing method described in any of the preceding claims.

[0107] This application further provides a computer device, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the signal processing method described in any of the preceding claims.

[0108] The method for AoA estimation in this embodiment may include the following steps: at the receiving end, the signal is received at a low intermediate frequency (IF) by adjusting back to zero frequency using a digital mixer; signal distortion caused by IQ imbalance in the UWB system is eliminated based on the low IF received signal; and the angle of arrival is acquired based on the signal after distortion elimination, thereby using the low IF to suppress the loss of AoA estimation accuracy caused by IQ imbalance in UWB. In practical scenarios, this method can also significantly suppress various effects of IQ imbalance, achieving good AoA estimation results even without IQ imbalance calibration or with poor IQ imbalance calibration results.

[0109] In one exemplary instance, the received signal processing method described in any of the embodiments of this application can be used to eliminate signal distortion caused by IQ imbalance in a UWB system.

[0110] In one optional embodiment, the angle of arrival is obtained based on the signal after signal distortion is eliminated. This angle of arrival can be obtained from the signal after cumulative processing. In the cumulatively processed signal, the length of the preamble of the synchronization segment sync is greater than 16 symbols, such as 16, 128, 512, 1024, 1536, 2048 or 4096 symbols.

[0111] Figure 3 This is a flowchart illustrating the method for AoA estimation in an embodiment of this application, as shown below. Figure 3 As shown, it may include:

[0112] Steps 300-302: The specific implementation is the same as steps 200-202, and will not be repeated here.

[0113] Step 303: Obtain the angle of arrival based on the accumulated processed signal.

[0114] In one exemplary instance, the phase difference β is extracted from the real and imaginary parts of the signal after the IQ imbalance has been eliminated through cumulative processing; the angle of arrival α of the received signal is calculated using the extracted phase difference β and the antenna parameters.

[0115] In one embodiment, the phase difference β can be extracted according to formula (21). In formula (21), since the complex form cosβ+jsinβ can be expressed as e jβ Therefore, P contains a complex phase β, while the preceding coefficients... It is a constant and does not affect phase extraction.

[0116] In one embodiment, the angle of arrival α of the signal can be calculated using the extracted phase difference β according to formula (22), as shown in formula (23):

[0117]

[0118] Where λ represents the wavelength of the signal.

[0119] The AoA estimation method provided in this application effectively suppresses the influence of IQ imbalance in the received signal by utilizing a low-IF reception method, thereby improving the AoA estimation accuracy in UWB. Especially when the IQ imbalance is not calibrated or the IQ imbalance calibration result is poor, the influence of IQ imbalance on the AoA estimation accuracy is greatly suppressed, and a very good AoA estimation result is obtained. This ensures that the angle of arrival is accurately calculated even in the presence of IQ imbalance, thereby improving the accuracy of target object position determination and the performance of the UWB system.

[0120] In practical scenarios, the AoA estimation method provided in this application significantly suppresses the impact of IQ imbalance, achieving good AoA estimation results even without IQ imbalance calibration or with poor IQ imbalance calibration results. For example, given an IQ imbalance parameter such as g = 1.1, Under the condition of using f o =+1MHz, such as Figure 4 As shown, according to the IEEE 802.15.4 protocol, when the synchronization code Nsync = 1024, the maximum error floor of the AoA estimation error within the range θ∈[0,2π) does not exceed 0.001°. This means that even with IQ imbalance, the AoA estimated using the method provided in this application is very accurate. The system exhibits good robustness in handling IQ imbalance problems and can provide high-precision signal direction estimation. In summary, the AoA estimation method provided in this application effectively suppresses the impact of IQ imbalance on the accuracy of AoA estimation, thereby improving the accuracy of target object position determination and system performance.

[0121] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the method for implementing AoA estimation as described in any of the preceding claims.

[0122] This application further provides a computer device, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the method for implementing AoA estimation as described in any of the preceding claims.

[0123] The received signal processing method provided in this application embodiment can be applied to links with at least two devices interacting (different crystal oscillators) or UWB communication modes, etc.

[0124] The method for AoA estimation provided in this application can be applied to links with at least two interacting devices (different crystal oscillators) or UWB communication modes.

[0125] Figure 5 This is a schematic diagram of the composition of the receiving signal processing device in the embodiments of this application, as shown below. Figure 4 As shown, it may include: a receiving module, a processing module, and a calculation module. The receiving module is used to receive signals using a low intermediate frequency (IF) to obtain a received signal, wherein there is an IF offset between the IF used by the receiving end and the IF used by the transmitting end. The processing module is used to process the received signal to eliminate the phase change in the received signal caused by the IF offset. The calculation module is used to perform cumulative calculations on the processed received signal.

[0126] In one exemplary instance, the processing module may be used to process the received signal according to a predefined phase term to eliminate phase changes in the received signal caused by intermediate frequency offset.

[0127] In one exemplary instance, the calculation module can be used to: sum and calculate the conjugate product of the received signal after eliminating the phase change introduced by the intermediate frequency offset, to obtain the cumulative result of the received signal.

[0128] The receiving signal processing apparatus provided in this application uses a low-IF received signal to eliminate the phase change introduced by the IF offset in the received signal, and then performs accumulation processing on the received signal after eliminating the phase change introduced by the IF offset in the received signal. The resulting signal effectively suppresses the influence of IQ imbalance in the received signal and improves the system's ability to suppress image frequency signals.

[0129] This application also provides a UWB device, including the receiving signal processing apparatus described in any one of the embodiments of this application.

[0130] This application provides another UWB device, including: a transmitter that transmits a signal using a first intermediate frequency (IF); a receiver that receives a signal using a second IF to achieve low-IF communication signal reception; the second IF has an IF offset relative to the first IF; and a processor that suppresses signal distortion caused by IQ imbalance based on the IF offset. Specifically, at the receiver, the suppression of signal distortion caused by IQ imbalance can be achieved using methods such as adjusting a digital mixer back to zero frequency.

[0131] In one exemplary instance, the processor is configured to employ the received signal processing method described in any one of the embodiments of this application to suppress signal distortion caused by IQ imbalance.

[0132] Figure 6 This is a schematic diagram of the structural composition of the device for implementing AoA estimation in the embodiments of this application, as shown below. Figure 6 As shown, in Figure 5 Based on the signal processing device shown, it also includes:

[0133] The acquisition module is used to obtain the angle of arrival based on the accumulated processed signal.

[0134] In one exemplary instance, the acquisition module can be used to:

[0135] The phase difference β is extracted from the real and imaginary parts of the received signal after cumulative processing; the angle of arrival α of the received signal is calculated using the extracted phase difference β and the antenna parameters.

[0136] The apparatus for AoA estimation provided in this application effectively suppresses the influence of IQ imbalance in the received signal by using a low-IF receiving method, thereby improving the estimation accuracy of AoA in UWB. Especially when the IQ imbalance is not calibrated or the IQ imbalance calibration result is poor, the impact of IQ imbalance on the accuracy of AoA estimation is greatly suppressed, and a very good AoA estimation result is obtained. This ensures that the angle of arrival is accurately calculated even in the presence of IQ imbalance, thereby improving the accuracy of target object position determination and the performance of the UWB system.

[0137] It should be noted that, in the embodiments of this application, IQ imbalance may include the imbalance between the signal amplitude and / or phase between the I-channel signal and the Q-channel signal.

[0138] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A method for processing received signals, applied to the receiver of an ultra-wideband (UWB) system, characterized in that, The receiving end uses low intermediate frequency to receive signals to obtain a received signal, wherein there is an intermediate frequency offset between the intermediate frequency used by the receiving end and the intermediate frequency used by the transmitting end. The received signal is processed to eliminate the phase change in the received signal caused by the intermediate frequency offset. The processed received signal is accumulated. The receiving end uses multiple antennas to receive signals.

2. The received signal processing method of claim 1, wherein, The received signal is processed to eliminate the phase change in the received signal caused by the intermediate frequency offset, comprising:

3. The received signal processing method of claim 1, wherein, The received signal is processed according to a predefined phase term to eliminate the phase change in the received signal caused by the intermediate frequency offset. The predefined phase term is determined based on the phase of the transmitted signal, the frequency difference between the intermediate frequencies of the transmitting end and the receiving end, and the sampling frequency.

4. The received signal processing method of claim 3, wherein, The received signal is processed according to the predefined phase term, comprising:

5. The received signal processing method of claim 4, wherein, The received signal is multiplied by the predefined phase term to eliminate the phase change in the received signal caused by the intermediate frequency offset. The processed received signal is accumulated, comprising:

6. The received signal processing method of claim 1, wherein The received signal after eliminating the phase change caused by the intermediate frequency offset is summed and conjugate multiplied to obtain the accumulation result of the received signal. The receiving end uses two antennas to receive signals; the accumulated received signal model can be represented as:

7. The received signal processing method of claim 6, wherein, In the UWB system, a binary phase shift keying (BPSK) signal is used for transmission. wherein is a coefficient related to gain and phase imbalance, cos β + j sin β is a term related to the phase of the signal; g is an IQ amplitude imbalance parameter; β = 2πd sin(a) represents the phase difference based on the angle of arrival a.

8. The received signal processing method according to any one of claims 1-7, wherein, The method comprises:

9. A method of implementing AoA estimation, the method comprising: The receiving end uses a digital mixer to return to zero frequency to realize low intermediate frequency reception of signals; Based on the low intermediate frequency received signal, signal distortion caused by IQ imbalance in the UWB system is eliminated; and Based on the signal after eliminating signal distortion, the angle of arrival is obtained.

10. The method of claim 9, wherein The receiving signal processing method of any one of claims 1-8 is used to eliminate signal distortion caused by IQ imbalance in the UWB system. Based on the signal after eliminating signal distortion, the angle of arrival is obtained, comprising:

11. The method of claim 9, wherein, The angle of arrival is obtained according to the accumulated processed signal; The length of the preamble of the sync segment sync in the accumulated processed signal is greater than 16 symbols. The angle of arrival is obtained according to the accumulated processed signal, comprising:

12. The method of claim 11, wherein, The phase difference β is extracted from the real part and the imaginary part of the accumulated received signal after the accumulation processing; The angle of arrival α of the received signal is calculated using the extracted phase difference β and antenna parameters.

14. A computer readable storage medium storing computer executable instructions for executing the receiving signal processing method of any one of claims 1-8, and / or the method for implementing AoA estimation of any one of claims 9-13.

13. The method of claim 12, wherein, The angle of arrival a is calculated according to the following formula: where λ represents the wavelength of the signal and d represents the distance between the receiving antennas. The memory stores instructions executable by the processor: steps for executing the receiving signal processing method of any one of claims 1-8, and / or steps for implementing the AoA estimation method of any one of claims 9-13.

15. A computer device comprising a memory and a processor, wherein, Comprise:

16. A signal processing device for receiving signals, characterized in that, Receiving module, processing module, calculation module, acquisition module, wherein, ​ The receiving module is configured to receive a signal using a low intermediate frequency to obtain a received signal, wherein an intermediate frequency offset exists between an intermediate frequency used by the receiving end and an intermediate frequency used by the transmitting end. The processing module is configured to process the received signal to eliminate a phase change introduced in the received signal due to the intermediate frequency offset. The calculation module is configured to perform accumulation operation on the processed received signal.

17. The received signal processing device of claim 16, wherein, The processing module is configured to: process the received signal according to a predefined phase term to eliminate the phase change introduced in the received signal due to the intermediate frequency offset.

18. The received signal processing device of claim 16, wherein, The calculation module is configured to: perform summation and conjugate multiplication calculation on the received signal from which the phase change introduced due to the intermediate frequency offset is eliminated to obtain the accumulated received signal.

19. A UWB device, characterized by The receiving signal processing device according to any one of claims 16-18.

20. A UWB device, characterized by The device comprises: a transmitting end configured to transmit a signal using a first intermediate frequency; a receiving end configured to receive a signal using a second intermediate frequency to implement low intermediate frequency communication signal reception; the second intermediate frequency has an intermediate frequency offset relative to the first intermediate frequency; and a processor configured to suppress signal distortion caused by IQ imbalance based on the intermediate frequency offset.

21. The UWB device of claim 20, wherein: the processor is configured to suppress signal distortion caused by IQ imbalance using the received signal processing method of any one of claims 1-8. ​

Images