Compensation method and device for IQ imbalance and communication equipment
By determining the second-order differential hopping subcarrier set S of the pilot signal in the receiver and calculating the IQ imbalance compensation coefficient, the received signal is compensated, which solves the problem of signal quality degradation caused by IQ imbalance, improves the receiver performance and reduces system complexity and cost.
Patent Information
- Application Number
- CN202411566486.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-02-28
AI Technical Summary
In wireless communication systems using zero-intermediate frequency architecture, the IQ imbalance of the transmitter or receiver leads to a decrease in signal quality, especially when the received signal strength is high, mirror interference becomes the main factor restricting the signal-to-noise ratio.
By determining the second-order differential hopping subcarrier set S of the pilot signal and calculating the IQ imbalance compensation coefficient that causes the objective function to obtain a minimum value, these coefficients are used to compensate the received signal IQ imbalance.
It effectively reduces the impact of IQ imbalance on signal quality, improves the performance of the receiver, and does not require special calibration circuits and time windows, reducing the complexity and cost of system design.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of wireless communications, and in particular, to a method and apparatus for compensating IQ imbalance, and a communication device. Background Art
[0002] Zero intermediate frequency architecture is a commonly used communication architecture in wireless communication systems. Its characteristics are that the transmitter modulates the signal directly from baseband to radio frequency, and the receiver converts the radio frequency signal directly to baseband signal without passing through the intermediate frequency. Therefore, the transceiver using zero intermediate frequency architecture usually has the advantages of small size and low power consumption. However, due to the IQ imbalance of the transmitter or receiver, that is, the deviation of the hardware circuit of the in-phase branch (I path) and the orthogonal branch (Q path) of the transmitter or receiver, such as the unequal gains of the I and Q mixers, the phase difference is not strictly 90°, etc. IQ imbalance will cause the orthogonal modulated signal to generate image interference, thereby reducing the signal quality. When the received signal strength is large, the image interference caused by IQ imbalance often becomes the main factor restricting the signal-to-noise ratio of the received signal. Therefore, it is necessary to estimate and compensate for the IQ imbalance of the communication system using zero intermediate frequency architecture.
[0003] For the IQ imbalance problem between the transmitter and the receiver, the transmitter often adopts the pre-compensation method for compensation, and the receiver often estimates and compensates through calibration. In the traditional receiver IQ imbalance calibration process, the receiver needs to be able to generate a pure RF single-tone signal or other types of reference signals without image interference to calibrate the IQ amplitude and phase imbalance inside the receiver. However, this self-calibration method cannot calculate the IQ imbalance of the transmitter (or the residual after the IQ imbalance compensation of the transmitter), and on the other hand, it requires the addition of a dedicated calibration circuit and calibration time, which places additional requirements on system design. Summary of the invention
[0004] An object of the present application is to provide a method and device for compensating IQ imbalance, so that a receiver can compensate for the IQ imbalance generated by a transmitter and a receiver, thereby improving the receiver performance.
[0005] In one aspect of the present application, a method for compensating IQ imbalance is provided, which comprises: determining a second-order differential hopping subcarrier set S of a pilot signal; calculating such that an objective function When the minimum value is obtained As IQ imbalance compensation coefficient in, Y P,k+i and Y P,N-(k+i) are the frequency domain received signals on the k+i and N-(k+i)th subcarriers, respectively, P,k+iis the frequency domain transmission pilot signal on the k+i subcarrier, N is the size of IDFT, i=-1,0 or 1, α is the preset power index, and α>0; use IQ imbalance compensation coefficient Perform IQ imbalance compensation on the received signal.
[0006] In some embodiments, determining the pilot signal second-order differential hopping subcarrier set S includes: initializing the pilot signal second-order differential hopping subcarrier set S to an empty set; calculating Δ(k)=|X for each subcarrier number k in turn. P,k+ 1 X P,N-k-1 +X P,k-1 X P,N-k+1 -2X P,k X P,N-k |Is it greater than the preset threshold value, where X P,N-k+i A pilot signal is transmitted in the frequency domain on the N-k+ith subcarrier, and in response to Δ(k) being greater than the preset threshold value, the subcarrier sequence number k is added to the second-order differential hopping subcarrier set S of the pilot signal.
[0007] In some embodiments, the objective function is calculated such that When the minimum value is obtained As IQ imbalance compensation coefficient Including: g C The uth element g of the candidate value set C,u and The vth element of the candidate value set calculate With the smallest Corresponding parameter combinations As the IQ imbalance compensation coefficient Where 0≤u <N g , N g For the g C The size of the candidate value set, For the The size of the set of candidate values.
[0008] In some embodiments, the IQ imbalance compensation coefficient is used Performing IQ imbalance compensation on the received signal includes: using the IQ imbalance compensation coefficient The IQ imbalance compensation is performed on the frequency domain received signal to obtain a compensated frequency domain received signal, wherein the compensated frequency domain received signal on the kth subcarrier is: Y k is the frequency domain received signal on the kth subcarrier, Y N-k is the frequency domain received signal on the Nk-th subcarrier.
[0009] In some embodiments, the IQ imbalance compensation coefficient is used Performing IQ imbalance compensation on the received signal includes: using the IQ imbalance compensation coefficient The baseband time domain received signal is subjected to IQ imbalance compensation to obtain a compensated baseband time domain received signal z(n), where: y I (n) and y Q (n) are the in-phase component and quadrature component of the baseband time domain received signal, 0≤n <N。
[0010] In a second aspect of the present application, an IQ imbalance compensation device is provided, which includes: a pilot signal second-order differential hopping subcarrier set determination module, which is configured to determine a pilot signal second-order differential hopping subcarrier set S; an IQ imbalance compensation coefficient calculation module, which is configured to calculate so that the objective function When the minimum value is obtained As IQ imbalance compensation coefficient in, Y P,k+i and Y P,N-(k+i) are the frequency domain received signals on the k+i and N-(k+i)th subcarriers, respectively, P,k+i A frequency domain transmission pilot signal on the k+i-th subcarrier, N is the size of the IDFT, i=-1, 0 or 1, α is a preset power index, and α>0; and an IQ imbalance compensation module, which is configured to use the IQ imbalance compensation coefficient Compensate the received signal.
[0011] According to a third aspect of the present application, a communication device is provided, which includes a processor and a non-transitory storage medium storing computer executable instructions, and the computer executable instructions can be executed by the processor to implement any of the above-mentioned IQ imbalance compensation methods.
[0012] A fourth aspect of the present application provides a communication device, comprising any one of the above-mentioned IQ imbalance compensation devices.
[0013] The above is an overview of the present application, which may be simplified, summarized, and omitted in detail. Therefore, those skilled in the art should recognize that this section is only illustrative and is not intended to limit the scope of the present application in any way. This summary section is neither intended to determine the key features or essential features of the claimed subject matter, nor is it intended to be an auxiliary means for determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other features of the present application will be more fully understood through the following description and the attached claims in conjunction with the accompanying drawings. It is understood that these drawings only depict several embodiments of the present application and should not be considered as limiting the scope of the present application. By using the accompanying drawings, the present application will be more clearly and detailed.
[0015] Figure 1 A schematic diagram showing the principle of an Orthogonal Frequency Division Multiplexing (OFDM) communication system using a zero intermediate frequency architecture is shown;
[0016] Figure 2 A model of IQ imbalance is shown;
[0017] Figure 3 A receiver 30 according to one embodiment of the present application is shown;
[0018] Figure 4 Shows Figure 3 The principle block diagram of the IQ imbalance compensation device 32 is shown;
[0019] Figure 5 A receiver 50 according to one embodiment of the present application is shown;
[0020] Figure 6 Shows Figure 5 The principle block diagram of the IQ imbalance compensation device 52 is shown;
[0021] Figure 7 A method 700 for compensating IQ imbalance according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION
[0022] The technical solution of the present application is described in detail below in conjunction with the accompanying drawings. In the accompanying drawings, similar symbols generally represent similar components, unless the context otherwise indicates. The specific implementation methods described in the detailed description, drawings and claims below are not intended to limit the scope of protection of the present application. Without departing from the spirit or scope of the subject matter of the present application, other implementation methods may be adopted, and modifications, combinations, equivalent substitutions or other changes may be made, all of which clearly constitute a part of the content of the present application and are included in the scope of protection of the present application.
[0023] Figure 1 The figure shows a schematic diagram of the principle of an Orthogonal Frequency Division Multiplexing (OFDM) communication system using a zero intermediate frequency architecture.
[0024] refer to Figure 1 , the OFDM communication system includes a transmitter 10 and a receiver 20. The transmitter 10 includes modules such as channel coding, constellation point mapping, pilot insertion, inverse discrete Fourier transform (IDFT), digital up-conversion and transmitter RF 11. The receiver 20 includes modules such as receiver RF 21, digital down-conversion, discrete Fourier transform (DFT), pilot extraction, channel estimation, constellation point demodulation, and channel decoding. After the RF signal output by the transmitter RF module is transmitted through the channel, the receiver 20 receives it through the receiver RF module, and after a series of processing corresponding to each module of the transmitter 10, the information sent by the transmitter is obtained.
[0025] Figure 1 In the figure, x(t) represents the time domain analog signal transmitted after digital up-conversion, and y(t) represents the time domain analog signal received after RF processing by the receiver. RF (t) represents the signal output by the transmitter RF, r RF (t) represents the signal input to the receiver RF. For each OFDM symbol, X k represents the frequency domain transmitted signal on the kth subcarrier, Y k represents the frequency domain received signal on the kth subcarrier; if the frequency domain transmitted signal on the kth subcarrier is a pilot signal, it is called the frequency domain transmitted pilot signal, which can be expressed as X P,k , the frequency domain received signal corresponding to the pilot subcarrier can be expressed as Y P,k x(n) represents the nth sampling point of the time domain signal obtained after the frequency domain transmission signal is IDFT, y(n) represents the nth sampling point of the time domain signal after the received time domain analog signal is digitally down-converted and sampled, N represents the number of frequency points of IDFT / DFT, 0≤n <N,0≤k<N; represents the IQ imbalance parameter of the transmitter, where g T is the amplitude imbalance parameter, is the phase imbalance parameter; represents the IQ imbalance parameter of the receiver, where g R is the amplitude imbalance parameter, is the phase imbalance parameter.
[0026] To facilitate understanding by those skilled in the art, Figure 2 A model of IQ imbalance is shown. Figure 2 In, x I (t),x Q (t) represent the in-phase component and quadrature component of the transmitted signal, that is, x(t) = x I (t)+jxQ (t);y I (t),y Q (t) represent the in-phase component and quadrature component of the received signal, that is, y(t) = y I (t)+jy Q (t); h(t) represents the impulse response of the channel, and n(t) represents the noise. Due to the influence of the IQ imbalance between the transmitter and the receiver, the received signal y(t) generates image interference.
[0027] In order to reduce the impact of IQ imbalance between the transmitter and the receiver, the present application uses the frequency domain pilot signal received by the receiver to calculate the IQ imbalance compensation coefficient Then the received signal is compensated to reduce the impact of the IQ imbalance between the transmitter and the receiver on the signal quality and improve the receiving performance. is the amplitude compensation coefficient, is the phase compensation coefficient. The IQ imbalance compensation of the present application can be performed in the time domain or in the frequency domain.
[0028] Figure 3 FIG. 3 shows a receiver 30 according to an embodiment of the present application. The receiver 30 adds an IQ imbalance compensation device 32 based on the receiver 20. In this embodiment, the IQ imbalance compensation device 32 performs IQ imbalance compensation on the received signal in the frequency domain. For one OFDM symbol, the IQ imbalance compensation device 32 receives the pilot signal Y in the frequency domain based on the output of the DFT module. P,k , calculate the IQ imbalance compensation coefficient and Then use and Compensate the frequency domain received signal and output the compensated frequency domain received signal Z k In a specific implementation, the IQ imbalance compensation device 32 may calculate the IQ imbalance compensation coefficient based on the current OFDM symbol. and The IQ imbalance compensation coefficient calculated based on the current OFDM symbol can also be used Used to perform IQ imbalance compensation on subsequent OFDM symbols.
[0029] Figure 4 Shows Figure 3 The schematic block diagram of the IQ imbalance compensation device 32 is shown. As shown in the figure, the IQ imbalance compensation device 32 includes a pilot signal second-order differential hopping subcarrier set determination module 321, an IQ imbalance compensation coefficient calculation module 322 and an IQ imbalance frequency domain compensation module 323.
[0030] The pilot signal second-order differential hopping subcarrier set determination module 321 is used to determine the pilot signal second-order differential hopping subcarrier set S. Specifically, the pilot signal second-order differential hopping subcarrier set S is first initialized to an empty set, and then for each subcarrier number k, Δ(k)=|X P,k+1 X P,N-k-1 +X P,k-1 X P,N-k+1 -2X P,k X P,N-k |Is it greater than the preset threshold value δ th , in response to Δ(k) being greater than a preset threshold value δ th , then add the subcarrier number k to the pilot signal second-order differential hopping subcarrier set S. In the present disclosure, satisfying Δ(k) greater than the preset threshold value δ th The subcarrier of is called the second-order differential hopping subcarrier of the pilot signal. Where |·| represents the modulus of the complex number, X P,k+i is the frequency domain transmission pilot signal on the k+i subcarrier, X P,N-k+i It is the frequency domain transmission pilot signal on the N-k+ith subcarrier, N is the size of IDFT, i = -1, 0 or 1. th is a real number greater than 0, and can be set according to the frequency domain transmission pilot situation. Preferably, the number of elements in the set S can be made as large as possible, and δ th In some embodiments, δ th Set to the average value of Δ(k). It should be noted that the present disclosure is applicable to the case where the pilot signal second-order differential hopping subcarrier set S is a non-empty set. In actual communication systems, a pseudo-random sequence is usually used as a pilot, so there are usually pilot signal second-order differential hopping subcarriers, that is, the set S is a non-empty set.
[0031] The IQ imbalance compensation coefficient calculation module 322 is used to calculate the IQ imbalance compensation coefficient in, is the amplitude compensation coefficient, is the phase compensation coefficient. In the present disclosure, the IQ imbalance compensation coefficient By the objective function Seek the best value, The g corresponding to the minimum value C and As IQ imbalance compensation coefficient and Considering that the amplitude and phase deviation caused by the IQ imbalance of the actual device will not exceed a certain range, it can be C and In the value range of The g corresponding to the minimum value C and As IQ imbalance compensation coefficient and In this disclosure, for the sake of convenience, g C and Represented as a binary parameter combination Will and Represented as a binary parameter combination Among them, the objective function Defined as
[0032]
[0033] Wherein, α is a preset power index, and α>0, which can be set to 1, 2 or other non-negative real numbers, S is the second-order differential hopping subcarrier set output by the pilot signal second-order differential hopping subcarrier set determination module 321, and X P,k+i is the frequency domain transmission pilot signal on the k+i-th subcarrier. Since the transmitter and the receiver communicate based on the same communication protocol, the frequency domain transmission pilot signal is known to both the transmitter and the receiver. Y P,k+i and Y P,N-(k+i) are the frequency domain received signals on the k+i and N-(k+i)th subcarriers, respectively, (·) * Represents the conjugate of a complex number, i = -1, 0 or 1.
[0034] Objective Function In the expression of It can be understood as the measurement value of the second-order difference of the rough channel estimate of the kth subcarrier after IQ imbalance compensation. In an ideal case where there is no IQ imbalance or other distortions of the transmitter and receiver, due to the continuity of the channel, the measurement value of the second-order difference of the rough channel estimate of the subcarrier is close to 0. However, under the influence of IQ imbalance, the measurement value of the second-order difference of the rough channel estimate of the subcarrier will deviate from 0. By minimizing the sum of the measurement values of the second-order differences of the rough channel estimates of multiple subcarriers, the impact caused by IQ imbalance is minimized. At this time, the corresponding IQ imbalance compensation coefficient is a better compensation coefficient.
[0035] is a two-dimensional nonlinear function, and its minimum value can be calculated by various conventional nonlinear optimization methods, such as gradient method, simulated annealing method, etc. Considering that the amplitude and phase of IQ imbalance are relatively small, a smaller range of g can be used. C and The value range of g C and The candidate value interval of The minimum value of .
[0036] In some embodiments, g C and Discretize the candidate value interval of g C and The candidate value set is then used to calculate the value of the objective function for each element in the set, and the g corresponding to the minimum value of the objective function is used to calculate the value of the objective function for each element in the set. C and The value of is used as the IQ imbalance compensation coefficient and If g C The candidate values of C,u},u=0,1,…,N g -1,N g g C The size of the candidate value set will The candidate values of for The size of the candidate value set is used to calculate the IQ imbalance compensation coefficient The process is: g C The uth element g of the candidate value set C,u and The vth element of the candidate value set calculate With the smallest Corresponding parameter combinations As IQ imbalance compensation coefficient
[0037] The above embodiment traverses The combination of candidate values can get the minimum value of the objective function, with high calculation accuracy but large amount of calculation.
[0038] In order to reduce the amount of calculation, you can first perform a one-dimensional search on one parameter, and then perform a one-dimensional search on another parameter, which can reduce the number of traversals to times, but it may not be the optimal value, but a suboptimal value.
[0039] In some embodiments, the phase imbalance coefficient may be fixed first, that is, Set to preset phase compensation value Sequentially C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g ; Then, in turn The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, Preset phase compensation value Can be set to In some embodiments, considering that the phase to be compensated is small, it is possible to set
[0040] In some other embodiments, the amplitude imbalance coefficient may be fixed first, that is, g C Set to preset amplitude compensation value Sequentially The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, Then, g C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g Similarly, the preset amplitude compensation value Can be set to g C In some embodiments, considering that the amplitude to be compensated is small, it is possible to set
[0041] The IQ imbalance frequency domain compensation module 323 uses the IQ imbalance compensation coefficient calculated by the IQ imbalance compensation coefficient calculation module 322 The IQ imbalance compensation is performed on the frequency domain received signal to obtain a compensated frequency domain received signal. Specifically, the compensated frequency domain received signal on the kth subcarrier is: Among them, Y k is the frequency domain received signal on the kth subcarrier, Y N-k is the frequency domain received signal on the Nkth subcarrier. The receiver 30 uses the compensated frequency domain received signal for subsequent processing, thereby reducing the impact caused by IQ imbalance and improving receiving performance.
[0042] Figure 5FIG. 5 shows a receiver 50 according to an embodiment of the present application. The receiver 50 adds an IQ imbalance compensation device 52 on the basis of the receiver 20. In this embodiment, the IQ imbalance compensation device 52 performs IQ imbalance compensation on the received signal in the time domain. Similar to the IQ imbalance compensation device 32, for one OFDM symbol, the IQ imbalance compensation device 52 receives the pilot signal Y in the frequency domain based on the output of the DFT module. P,k , calculate the IQ imbalance compensation coefficient However, unlike the IQ imbalance compensation device 32, the IQ imbalance compensation device 52 performs IQ imbalance compensation on the time domain received signal after digital down-conversion and outputs the compensated time domain received signal. In specific implementation, the IQ imbalance compensation device 52 can calculate the IQ imbalance compensation coefficient based on the current OFDM symbol. And perform IQ imbalance compensation on the current OFDM symbol. This method requires caching the time domain signal after digital down-conversion. After that, IQ imbalance compensation is performed on the cached data. The IQ imbalance compensation coefficient calculated based on the current OFDM symbol can also be used It is used to perform IQ imbalance compensation for subsequent OFDM symbols. This method can perform pipeline operation without caching the data after digital down-conversion.
[0043] Figure 6 Shows Figure 5 The schematic block diagram of the IQ imbalance compensation device 52 is shown. As shown in the figure, the IQ imbalance compensation device 52 includes a pilot signal second-order differential hopping subcarrier set determination module 521, an IQ imbalance compensation coefficient calculation module 522 and an IQ imbalance time domain compensation module 523.
[0044] The pilot signal second-order differential hopping subcarrier set determination module 521 and Figure 4 The pilot signal second-order differential hopping subcarrier set determining module 321 shown is the same, and is used to determine the pilot signal second-order differential hopping subcarrier set S.
[0045] IQ imbalance compensation coefficient calculation module 522 and Figure 4 The IQ imbalance compensation coefficient calculation module 322 shown in FIG. 1 is the same as that shown in FIG. 1 , and is used to calculate the IQ imbalance compensation coefficient
[0046] The IQ imbalance time domain compensation module 523 uses the IQ imbalance compensation coefficient calculated by the IQ imbalance compensation coefficient calculation module 522 The IQ imbalance compensation is performed on the time domain received signal to obtain a compensated time domain received signal. Specifically, the IQ imbalance time domain compensation module 523 performs IQ imbalance compensation on the time domain baseband signal y(n) obtained by digital down-conversion, and the compensated time domain baseband signal is Denote y(n) as its in-phase component y I (n) and the orthogonal component y Q (n), that is, y(n) = y I (n)+jy Q (n), and then substitute it into the above expression of z(n), and we can further obtain: 0≤n <N。
[0047] Figure 7 A method 700 for compensating IQ imbalance according to an embodiment of the present disclosure is shown. The method 700 may be used, for example, Figure 4 and Figure 6 The IQ imbalance compensation device shown is used to achieve this.
[0048] like Figure 7 As shown, the IQ imbalance compensation method 700 includes the following steps 710-730.
[0049] In step 710, a second-order differential hopping subcarrier set S of a pilot signal is determined.
[0050] First, the set S is initialized to an empty set, and then for each subcarrier number k, Δ(k)=|X P,k+ 1 X P,N-k-1 +X P,k-1 X P,N-k+1 -2X P,k X P,N-k | is greater than a preset threshold value, in response to Δ(k) being greater than the preset threshold value, adding the subcarrier number k to the pilot signal second-order differential hopping subcarrier set S. Wherein, X P,k+i is the frequency domain transmission pilot signal on the k+i subcarrier, X P,N-k+i The pilot signal is transmitted in the frequency domain on the N-k+i-th subcarrier, where N is the size of the IDFT and i=-1, 0 or 1.
[0051] In step 720, the objective function is calculated. When the minimum value is obtained As IQ imbalance compensation coefficient
[0052] About the objective function For the calculation process of the IQ imbalance compensation coefficient, please refer to the relevant description of the IQ imbalance compensation coefficient calculation module 322.
[0053] In step 730, the IQ imbalance compensation coefficient Perform IQ imbalance compensation on the received signal.
[0054] In some embodiments, IQ imbalance compensation for the received signal can be performed in the frequency domain, that is, using the IQ imbalance compensation coefficient The IQ imbalance compensation is performed on the frequency domain received signal to obtain a compensated frequency domain received signal. The compensated frequency domain received signal on the kth subcarrier is: Y k is the frequency domain received signal on the kth subcarrier, Y N-k is the frequency domain received signal on the Nk-th subcarrier.
[0055] In some embodiments, IQ imbalance compensation for the received signal can be performed in the time domain, that is, using the IQ imbalance compensation coefficient The baseband time domain received signal is subjected to IQ imbalance compensation to obtain a compensated baseband time domain received signal z(n), where: y I (n) and y Q (n) are the in-phase component and quadrature component of the baseband time domain received signal, 0≤n <N。
[0056] The IQ imbalance compensation method and device of the present application use the received pilot signal to calculate the IQ imbalance compensation parameters, and then use the calculated parameters to perform IQ imbalance compensation on the received signal. Using the method of the present application, there is no need to use a special circuit for IQ calibration, nor is there a need for a special time window for calibration, which can reduce the cost of the receiver. In addition, the IQ imbalance compensation method and device of the present application simultaneously compensate for the combined impact of the IQ imbalance of the transmitter and the receiver, without the need to perform the IQ imbalance parameters of the transmitter and the receiver separately, and has strong adaptability, and can obtain better compensation performance. The IQ imbalance compensation method of the present application can be applied to receivers of various communication systems using OFDM modulation.
[0057] The present disclosure also provides a communication device, which includes a processor and a non-transitory storage medium storing computer-executable instructions, wherein the computer-executable instructions can be executed by the processor to perform each step in any one of the above method embodiments.
[0058] In addition, the present disclosure also provides a communication device, which includes any one of the above-mentioned IQ imbalance compensation devices.
[0059] It should be understood that the division of devices and modules in the embodiments provided in this application is exemplary, and there may be other division methods in actual implementation. A person of ordinary skill in the art can understand and implement other changes to the disclosed implementation methods by reading the specification, the disclosed content, the drawings and the attached claims, and they all fall within the scope of protection of the claims of this disclosure without departing from the essence of the claims of this disclosure. In the claims, the wording "comprising" does not exclude other elements and steps, and the words "one" and "an" do not exclude the plural. In the actual application of this application, a part or module may perform the functions of multiple technical features cited in the claims. Any figure marks in the claims should not be construed as limiting the scope.
Claims
1. A method for compensating IQ imbalance, characterized in that: The method comprises: Determine a second-order differential hopping subcarrier set S of the pilot signal; Calculate the objective function When the minimum value is obtained As IQ imbalance compensation coefficient in, Y P,k+i and Y P,N-(k+i) are the frequency domain received signals on the k+i and N-(k+i)th subcarriers, respectively, P,k+i is a frequency domain transmission pilot signal on the k+i th subcarrier, N is the size of the IDFT, i=-1, 0 or 1, α is a preset power index, and α>0; and Using the IQ imbalance compensation coefficient Perform IQ imbalance compensation on the received signal.
2. The method according to claim 1, characterized in that Determining the second-order differential hopping subcarrier set S of the pilot signal includes: Initializing the pilot signal second-order differential hopping subcarrier set S to an empty set; For each subcarrier number k, calculate Δ(k)=|X P,k+1 X P,N-k-1 +X P,k-1 X P,N-k+1 -2X P,k X P,N-k |Is it greater than the preset threshold value, where X P,N-k+i transmitting a pilot signal in the frequency domain on the N-k+i th subcarrier; and In response to Δ(k) being greater than the preset threshold value, adding the subcarrier sequence number k to the second-order differential hopping subcarrier set S of the pilot signal.
3. The method according to claim 1, characterized in that Calculate the objective function When the minimum value is obtained As IQ imbalance compensation coefficient include: Sequentially C The uth element g of the candidate value set C,u and The vth element of the candidate value set calculate With the smallest Corresponding parameter combinations As the IQ imbalance compensation coefficient Where 0≤u <N g , N g For the g C The size of the candidate value set, For the The size of the set of candidate values.
4. The method according to claim 1, characterized in that Calculate the objective function When the minimum value is obtained As IQ imbalance compensation coefficient include: Sequentially C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g , N g For the g C The size of the candidate value set, is a preset phase compensation value; and Sequentially The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, For the The size of the set of candidate values.
5. The method according to claim 1, characterized in that Calculate the objective function When the minimum value is obtained As IQ imbalance compensation coefficient include: Sequentially The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, For the The size of the candidate value set, is a preset amplitude compensation value; and Sequentially C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g , N g For the g C The size of the set of candidate values.
6. The method according to claim 1, characterized in that Using the IQ imbalance compensation coefficient The IQ imbalance compensation for the received signal includes: Using the IQ imbalance compensation coefficient The IQ imbalance compensation is performed on the frequency domain received signal to obtain a compensated frequency domain received signal, wherein the compensated frequency domain received signal on the kth subcarrier is: Y k is the frequency domain received signal on the kth subcarrier, Y N-k is the frequency domain received signal on the Nk-th subcarrier.
7. The method according to claim 1, characterized in that Using the IQ imbalance compensation coefficient The IQ imbalance compensation for the received signal includes: Using the IQ imbalance compensation coefficient The baseband time domain received signal is subjected to IQ imbalance compensation to obtain a compensated baseband time domain received signal z(n), where: y I (n) and y Q (n) are the in-phase component and quadrature component of the baseband time domain received signal, 0≤n <N。 8. A device for compensating IQ imbalance, comprising: A pilot signal second-order differential hopping subcarrier set determination module, configured to determine a pilot signal second-order differential hopping subcarrier set S; The IQ imbalance compensation coefficient calculation module is configured to calculate the objective function When the minimum value is obtained As IQ imbalance compensation coefficient in, Y P,k+i and Y P,N-(k+i) are the frequency domain received signals on the k+i and N-(k+i)th subcarriers, respectively, P,k+i is the frequency domain transmission pilot signal on the k+i-th subcarrier, N is the size of IDFT, i=-1, 0 or 1, α is the preset power index, and α>0; as well as An IQ imbalance compensation module is configured to use the IQ imbalance compensation coefficient Compensate the received signal.
9. The IQ imbalance compensation device according to claim 8, characterized in that: The pilot signal second-order differential hopping subcarrier set determination module is further configured to: Initializing the pilot signal second-order differential hopping subcarrier set S to an empty set; For each subcarrier number K, calculate Δ(k)=|X P,k+1 X P,n-K-1 +X P,k-1 X P,N-k+1 -2X P,k X P,N-k |Is it greater than the preset threshold value, where X P,N-k+i A pilot signal is transmitted in the frequency domain on the N-k+i-th subcarrier; as well as In response to Δ(k) being greater than the preset threshold value, adding the subcarrier sequence number k to the second-order differential hopping subcarrier set S of the pilot signal.
10. The IQ imbalance compensation device according to claim 8, characterized in that: The IQ imbalance compensation coefficient calculation module is further configured to: Sequentially C The uth element g of the candidate value set C,u and The vth element of the candidate value set calculate With the smallest Corresponding parameter combinations As the IQ imbalance compensation coefficient Where 0≤u <N g , N g For the g C The size of the candidate value set, For the The size of the set of candidate values.
11. The IQ imbalance compensation device according to claim 8, characterized in that: The IQ imbalance compensation coefficient calculation module includes: The amplitude compensation coefficient estimation module is configured to sequentially calculate g C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g , N g For the g C The size of the candidate value set, is the preset phase compensation value; The phase compensation coefficient estimation module is configured to sequentially The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, For the The size of the set of candidate values.
12. The IQ imbalance compensation device according to claim 8, characterized in that: The IQ imbalance compensation coefficient calculation module includes: The phase compensation coefficient estimation module is configured to sequentially The vth element of the candidate value set calculate by The corresponding minimum value As the phase compensation coefficient in, For the The size of the candidate value set, is the preset amplitude compensation value; The amplitude compensation coefficient estimation module is configured to sequentially calculate g C The uth element g of the candidate value set C,u ,calculate by The g corresponding to the minimum value C,u As the amplitude compensation factor Where 0≤u <N g , N g For the g C The size of the set of candidate values.
13. The IQ imbalance compensation device according to claim 8, characterized in that: The IQ imbalance compensation module comprises: An IQ imbalance frequency domain compensation module is configured to use the IQ imbalance compensation coefficient The frequency domain received signal is compensated to obtain a compensated frequency domain received signal, wherein the compensated frequency domain received signal on the kth subcarrier is Y k is the frequency domain received signal on the kth subcarrier, Y N-k is the frequency domain received signal on the Nk-th subcarrier.
14. The IQ imbalance compensation device according to claim 8, characterized in that: The IQ imbalance compensation module comprises: An IQ imbalance time domain compensation module is configured to use the IQ imbalance compensation coefficient The baseband time domain received signal is compensated to obtain a compensated baseband time domain received signal z(n), where: y I (n) and y Q (n) are the in-phase component and quadrature component of the baseband time domain received signal, 0≤n <N。 15. A communication device comprising a processor and a non-transitory storage medium storing computer executable instructions, wherein the computer executable instructions can be executed by the processor according to any one of claims 1 to 7.
16. A communication device, comprising the apparatus according to any one of claims 8 to 14.