CN115412417A - Carrier initial phase determining method, device, terminal and storage medium - Google Patents
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- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
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Abstract
The application discloses a carrier initial phase determining method, a carrier initial phase determining device, a carrier initial phase determining terminal and a storage medium, wherein the method comprises the following steps: receiving an initial time domain signal; determining an LTF time domain signal based on the initial time domain signal; determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal; and determining the initial phase of the carrier based on m target channel phases corresponding to m nonzero subcarriers. The invention uses the inherent long training sequence in the preamble of the WLAN signal, takes the phase of the WLAN signal after channel estimation, considers the influence of synchronous timing error and cyclic delay, and estimates the initial phase of the carrier wave by operation. The method has simple calculation of the estimated phase and higher accuracy.
Description
Technical Field
The present application relates to the field of phase estimation technologies, and in particular, to a method, an apparatus, a terminal, and a storage medium for determining an initial phase of a carrier.
Background
During WLAN signal transmission, a certain phase difference exists between a carrier used for IQ modulation at a transmitting end and a carrier used for IQ demodulation at a receiving end. When IQ imbalance exists at a transmitting end, the phase difference can affect estimation of IQ imbalance at the receiving end, and further affect link performance. Therefore, how to accurately estimate the initial phase of the carrier becomes an urgent problem to be solved.
Currently, for the estimation of the initial phase of the carrier, a frame start position is obtained mainly by synchronous detection, a Long Training Field (LTF) time domain sampling sequence of a received signal is taken out, then the phase of the LTF time domain sampling sequence of the received signal is taken out to be different from the local LTF time domain sampling sequence, so as to obtain the time domain phase difference of each sampling point, and then the time domain phase difference is averaged to obtain the estimated value of the initial phase of the carrier.
However, when the above method is applied to a signal with a timing error or a MIMO signal added with a Cyclic Shift (CSD), different transmit antennas may perform different time domain Cyclic shifts on the LTF, so that a Cyclic delay exists between the LTF of the received signal and the local LTF, resulting in a problem of low accuracy of the calculated estimated value of the initial phase of the carrier.
Disclosure of Invention
The present application mainly aims to provide a method, an apparatus, a terminal and a storage medium for determining a carrier initial phase, so as to solve the problem of low accuracy of an estimated value of a calculated carrier initial phase in the related art.
In order to achieve the above object, in a first aspect, the present application provides a carrier initial phase determining method, including:
receiving an initial time domain signal;
determining an LTF time domain signal based on the initial time domain signal;
determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, wherein the m non-zero subcarriers correspond to the m target channel phases one to one, and m is an integer;
and determining the initial phase of the carrier based on m target channel phases corresponding to m nonzero subcarriers.
In one possible implementation, determining the LTF time-domain signal based on the initial time-domain signal includes:
and carrying out synchronous timing estimation on the initial time domain signal to obtain an LTF time domain signal.
In one possible implementation manner, determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time-domain signal includes:
sequentially carrying out frequency offset estimation and frequency offset compensation on the LTF time domain signal to obtain a frequency offset compensated LTF time domain signal;
and determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal after frequency offset compensation.
In a possible implementation manner, determining m target channel phases corresponding to m nonzero subcarriers based on an LTF time domain signal after frequency offset compensation includes:
performing channel estimation on the LTF time domain signal after frequency offset compensation to obtain m channel values corresponding to m non-zero subcarriers, wherein the m non-zero subcarriers correspond to the m channel values one by one;
acquiring m phases corresponding to m channel values to obtain m initial channel phases corresponding to m non-zero subcarriers, wherein the m channel values correspond to the m phases and the m initial channel phases one to one;
and removing the phase rotation on the m initial channel phases to obtain m target channel phases, wherein the m initial channel phases correspond to the m target channel phases one to one.
In a possible implementation manner, determining an initial phase of a carrier based on m target channel phases corresponding to m non-zero subcarriers includes:
and performing linear fitting on the m target channel phases to obtain carrier initial phases.
In one possible implementation, m is an even number greater than or equal to 2;
performing linear fitting on the phases of the m target channels to obtain initial phases of carriers, wherein the steps comprise:
calculating slopes corresponding to the m target channel phases; determining m/2 initial channel phases corresponding to the zero subcarrier based on the slope and the m target channel phases;
and calculating the average value of m/2 initial channel phases to obtain a target channel phase corresponding to the zero subcarrier, and taking the target channel phase corresponding to the zero subcarrier as the initial carrier phase.
In one possible implementation manner, determining m/2 initial channel phases corresponding to the zero subcarrier based on the slope and m target channel phases includes:
selecting two target channel phases corresponding to two symmetrical non-zero subcarriers from the m target channel phases, and determining a reference value based on the slope and the two target channel phases;
selecting m-2 target channel phases except for two target channel phases from the m target channel phases, and obtaining (m-2)/2 initial channel phases based on the m-2 target channel phases, the slope and a reference value;
and summarizing the reference value and (m-2)/2 initial channel phases to obtain m/2 initial channel phases.
In a second aspect, an embodiment of the present invention provides a carrier initial phase determining apparatus, including:
the first signal receiving module is used for receiving an initial time domain signal;
a second signal determination module to determine an LTF time domain signal based on the initial time domain signal;
the channel phase determining module is used for determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, wherein the m non-zero subcarriers correspond to the m target channel phases one to one, and m is an integer;
and the initial phase determining module is used for determining the initial phase of the carrier based on the m target channel phases corresponding to the m nonzero subcarriers.
In a third aspect, an embodiment of the present invention provides a terminal, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the steps of any one of the above methods for determining an initial phase of a carrier.
In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the steps of any one of the above methods for determining an initial phase of a carrier are implemented.
The embodiment of the invention provides a method, a device, a terminal and a storage medium for determining a carrier initial phase, wherein the method comprises the following steps: the method comprises the steps of receiving an initial time domain signal, determining an LTF time domain signal based on the initial time domain signal, then determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, and then determining a carrier initial phase based on the m target channel phases corresponding to the m non-zero subcarriers. The invention uses the inherent long training sequence in the preamble of the WLAN signal, takes the phase of the WLAN signal after channel estimation, considers the influence of synchronous timing error and cyclic delay, and estimates the initial phase of the carrier wave by operation. The method has simple phase estimation calculation and higher accuracy.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and the description of the exemplary embodiments of the present application are provided for explaining the present application and do not constitute an undue limitation on the present application. In the drawings:
fig. 1 is a schematic diagram of a WLAN-oriented communication system model according to an embodiment of the present invention;
fig. 2 is a flowchart of an implementation of a method for determining an initial phase of a carrier according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a target channel phase corresponding to a subcarrier according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a carrier initial phase determining apparatus according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a terminal according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein.
It should be understood that, in the various embodiments of the present invention, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
It should be understood that in the present application, "comprising" and "having" and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that, in the present invention, "a plurality" means two or more. "and/or" is merely an association describing an associated object, meaning that three relationships may exist, for example, and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "comprising a, B and C", "comprising a, B, C" means that all three of a, B, C are comprised, "comprising a, B or C" means comprising one of a, B, C, "comprising a, B and/or C" means comprising any 1 or any 2 or 3 of a, B, C.
It should be understood that in the present invention, "B corresponding to a", "a corresponds to B", or "B corresponds to a" means that B is associated with a, and B can be determined from a. Determining B from a does not mean determining B from a alone, but may be determined from a and/or other information. And the matching of A and B means that the similarity of A and B is greater than or equal to a preset threshold value.
As used herein, "if" may be interpreted as "at \8230; \8230when" or "when 8230; \8230when" or "in response to a determination" or "in response to a detection", depending on the context.
The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description is made by way of specific embodiments with reference to the accompanying drawings.
In the WLAN communication system model shown in fig. 1, a signal x to be transmitted i (t) and x q (t) IQ modulation is carried out on the transmitting end, amplitude Attenuation and White Gaussian Noise (AWGN) are added, and then IQ demodulation is carried out on the receiving end to obtain a received signal y i (t) and y q (t)。
In the above process, there may be IQ imbalance at the transmitting end, and the amplitude factor and the phase factor of IQ imbalance are set as epsilon and epsilon respectively
The carrier used for IQ demodulation at the receiving end may have a frequency offset and an initial phase with respect to the carrier at the transmitting end, the frequency offset is set to Δ f, the initial phase is set to θ, and both the frequency offset Δ f and the initial phase θ may affect IQ imbalance estimation at the transmitting end.
Therefore, the receiving end is used as standard equipment to remove the influence of frequency offset and initial phase so as to estimate and compensate IQ imbalance existing at the transmitting end and further recover the original signal, which is the technical problem solved by the invention.
The invention provides a carrier initial phase determining method aiming at the problems, wherein the method uses the inherent long training sequence in the preamble of the WLAN signal, removes the influence of synchronous timing error and cyclic delay and has higher estimation accuracy.
In one embodiment, as shown in fig. 2, a method for determining initial phase of carrier is provided, which includes the following steps:
step S201: receiving an initial time domain signal;
step S202: based on the initial time domain signal, an LTF time domain signal is determined.
The initial time domain signal may be a WLAN MIMO signal or a non-MIMO signal.
After the receiving end receives the initial time domain signal, synchronous timing estimation is carried out on the initial time domain signal, the position of the LTF time domain signal can be positioned, and then the LTF time domain signal is taken out, so that the LTF time domain signal can be directly obtained.
Step S203: and determining m target channel phases corresponding to the m non-zero subcarriers based on the LTF time domain signal.
Wherein, m nonzero subcarriers correspond to m target channel phases one to one, and m is an integer.
For determining m target channel phases corresponding to m non-zero subcarriers, frequency offset estimation and frequency offset compensation are sequentially performed on the LTF time domain signal to obtain a frequency offset compensated LTF time domain signal, and then m target channel phases corresponding to m non-zero subcarriers are determined based on the frequency offset compensated LTF time domain signal.
Determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal after frequency offset compensation, and performing channel estimation on the LTF time domain signal after frequency offset compensation to obtain m channel values corresponding to m non-zero subcarriers, wherein the m non-zero subcarriers correspond to the m channel values one by one; then m phases corresponding to the m channel values are obtained, and m initial channel phases corresponding to the m non-zero subcarriers are obtained, wherein the m channel values correspond to the m phases and the m initial channel phases one to one; and finally, removing the phase rotation on the m initial channel phases to obtain m target channel phases, wherein the m initial channel phases correspond to the m target channel phases one to one.
In some embodiments, referring to fig. 3, a process of determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal is described as follows:
taking the initial time domain signal as a WLAN signal, taking m as 52 as an example, after the LTF time domain signal is extracted from the WLAN signal, frequency offset estimation and frequency offset compensation are sequentially performed on the LTF time domain signal to obtain a frequency offset compensated LTF time domain signal. Wherein, the frequency offset compensation can use LTF delay correlation method to estimate frequency offset, and then remove frequency offset part.
Then, channel estimation is performed on the LTF time domain signal after frequency offset compensation to obtain 52 channel values corresponding to 52 non-zero subcarriers, and then, a phase corresponding to each channel value is obtained, so that 52 initial channel phases corresponding to 52 non-zero subcarriers can be obtained.
Since the large bandwidth WLAN signal is transmitted with a known phase rotation added to each 20M signal, it should be removed preferentially after channel estimation. Therefore, the phase rotation on each of the 52 initial channel phases needs to be removed to obtain the target channel phase corresponding to each non-zero subcarrier.
Wherein the target channel phase φ (k) comprises: initial phase θ, phase shift due to IQ imbalance, phase noise due to white noise. The phase shift due to IQ imbalance and the phase noise due to white noise are small compared to the initial phase θ and can be ignored here.
In addition, WLAN receivers typically introduce synchronization timing errors and CSD if multiple antennas are present, in which case the target channel phase phi (k) will add a phase shift that is linearly related to frequency.
In summary, the calculation formula of the target channel phase Φ (k) can be expressed as:
where k is the subcarrier number, Δ N represents the time domain delay or the cyclic shift, and N represents the number of FFT subcarriers. At this time, the target channel phase φ (k), varies linearly with frequency. Because φ (k) E [ - π, a transition occurs when φ (k) ≧ π or φ (k) < - π.
Step S104: and determining the initial phase of the carrier based on the m target channel phases corresponding to the m non-zero subcarriers.
For determining the initial phase of the carrier, linear fitting needs to be performed on m target channel phases to obtain the initial phase of the carrier, wherein m is an even number greater than or equal to 2.
Based on the phase characteristic, the phase value at the 0 subcarrier is not affected by the linear phase variation, with phi (0) ≈ theta. And because the value of the frequency point 0 of the LTF is 0, the LTF cannot be used for estimating a channel, and therefore, a linear fitting method is required to obtain the value phi (0).
And performing linear fitting on the m target channel phases, calculating slopes corresponding to the m target channel phases, determining m/2 initial channel phases corresponding to the zero subcarrier based on the slopes and the m target channel phases, calculating an average value of the m/2 initial channel phases to obtain a target channel phase corresponding to the zero subcarrier, and taking the target channel phase corresponding to the zero subcarrier as a carrier initial phase.
Wherein, based on the slope and m target channel phases, determining m/2 initial channel phases corresponding to the zero subcarrier includes: selecting two target channel phases corresponding to two symmetrical non-zero subcarriers from the m target channel phases, determining a reference value based on a slope and the two target channel phases, then selecting m-2 target channel phases except the two target channel phases from the m target channel phases, obtaining (m-2)/2 initial channel phases based on the m-2 target channel phases, the slope and the reference value, and then summarizing the reference value and the (m-2)/2 initial channel phases to obtain the m/2 initial channel phases.
In some embodiments, a process of performing linear fitting on m target channel phases to obtain initial carrier phases is described as follows:
as can be seen from fig. 3, the target channel phase phi (k) corresponding to the non-zero subcarrier has several jump points from-pi to pi. And (c) segmenting phi (k) according to the jump points, wherein no numerical value jump exists in each segment, then respectively calculating the slope of each segment, and averaging to obtain an average slope which is recorded as a slope (slope estimated value) kappa.
Then, a pair of symmetrical frequency points is taken, and the phase value at the position of 0 subcarrier is estimated according to the slope kappa and is used as a reference value. To reduce the influence of slope estimation errors, the symmetric frequency points closest to the center can be taken. The reference value can be used as a basis for evaluating whether phase deviation exists in the rest of the estimated values.
And then taking the rest symmetrical frequency points, respectively estimating phase values at 0 subcarrier, and performing phase deviation compensation according to the reference value. Because the slope estimation has a certain error range, the symmetric frequency points are taken to calculate the mean value and estimate the phase value at the position of 0 subcarrier, and the influence of the slope error can not be introduced. Because the phase is limited in the range of [ -pi, pi) and the phase jump caused by the error is considered, the mean value of the symmetrical frequency points may have a deviation of + -pi or even + -2 pi from phi (0), and compensation is needed according to the reference value.
And averaging the phase values of all the 0 subcarriers in the previous step to obtain the initial phase (estimated value) of the carrier. Compared with a reference value, the result after the averaging can inhibit phase noise, reduce estimation errors and enable the estimation result to be more accurate.
The invention estimates and compensates the frequency deviation in advance, can resist the influence of synchronous timing error and CSD, reduces phase shift and phase noise caused by IQ imbalance by adopting a multi-carrier mean value solving mode, and has good initial phase estimation effect. In addition, the calculation is simpler, the calculation cost is low, and the accuracy is higher.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
The following are embodiments of the apparatus of the invention, reference being made to the corresponding method embodiments described above for details which are not described in detail therein.
Fig. 4 shows a schematic structural diagram of a carrier initial phase determining apparatus provided in an embodiment of the present invention, and for convenience of description, only a part related to the embodiment of the present invention is shown, and the carrier initial phase determining apparatus includes a first signal receiving module 41, a second signal determining module 42, a channel phase determining module 43, and an initial phase determining module 44, specifically as follows:
a first signal receiving module 41, configured to receive an initial time domain signal;
a second signal determining module 42, configured to determine an LTF time-domain signal based on the initial time-domain signal;
a channel phase determining module 43, configured to determine m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, where the m non-zero subcarriers correspond to the m target channel phases one to one, and m is an integer;
an initial phase determining module 44, configured to determine initial phases of carriers based on m target channel phases corresponding to m non-zero subcarriers.
In one possible implementation, the second signal determining module 42 includes:
and the second time domain information determining submodule is used for carrying out synchronous timing estimation on the initial time domain signal to obtain an LTF time domain signal.
In one possible implementation, the channel phase determining module 43 includes:
the frequency offset calculation submodule is used for carrying out frequency offset estimation and frequency offset compensation on the LTF time domain signal in sequence to obtain the LTF time domain signal after the frequency offset compensation;
and the channel phase determining submodule is used for determining m target channel phases corresponding to m nonzero subcarriers based on the LTF time domain signal after frequency offset compensation.
In one possible implementation, the channel phase determining sub-module includes:
the channel estimation unit is used for performing channel estimation on the LTF time domain signal after the frequency offset compensation to obtain m channel values corresponding to m non-zero subcarriers, wherein the m non-zero subcarriers correspond to the m channel values one by one;
an initial channel phase determining unit, configured to obtain m phases corresponding to m channel values, and obtain m initial channel phases corresponding to m non-zero subcarriers, where the m channel values correspond to the m phases and the m initial channel phases one to one;
and the target channel phase determining unit is used for removing phase rotation on the m initial channel phases to obtain m target channel phases, wherein the m initial channel phases are in one-to-one correspondence with the m target channel phases.
In one possible implementation, the initial phase determining module 44 includes:
and the linear fitting submodule is used for performing linear fitting on the m target channel phases to obtain the initial carrier phase.
In one possible implementation, m is an even number greater than or equal to 2;
the linear fitting submodule includes:
the slope calculation unit is used for calculating slopes corresponding to the m target channel phases;
the initial channel phase calculation unit is used for determining m/2 initial channel phases corresponding to the zero subcarrier based on the slope and the m target channel phases;
and the initial phase determining unit is used for calculating the average value of m/2 initial channel phases to obtain a target channel phase corresponding to the zero subcarrier, and taking the target channel phase corresponding to the zero subcarrier as the initial carrier phase.
In one possible implementation, the initial channel phase calculation unit includes:
the reference value calculating operator unit is used for selecting two target channel phases corresponding to two symmetrical non-zero subcarriers from the m target channel phases and determining a reference value based on the slope and the two target channel phases;
the initial channel phase calculation subunit is used for selecting m-2 target channel phases except for two target channel phases from the m target channel phases and obtaining (m-2)/2 initial channel phases based on the m-2 target channel phases, the slope and a reference value;
and the initial channel phase determining subunit is used for summarizing the reference value and (m-2)/2 initial channel phases to obtain m/2 initial channel phases.
Fig. 5 is a schematic diagram of a terminal according to an embodiment of the present invention. As shown in fig. 5, the terminal 5 of this embodiment includes: a processor 51, a memory 52 and a computer program 53 stored in the memory 52 and executable on the processor 51. The processor 51, when executing the computer program 53, implements the steps in the various embodiments of the carrier initial phase determination method described above, such as the steps 201 to 204 shown in fig. 2. Alternatively, the processor 51 implements the functions of the respective modules/units in the above-described respective embodiments of the carrier initial phase determining apparatus, such as the modules/units 41 to 44 shown in fig. 4, when executing the computer program 53.
The present invention also provides a readable storage medium, in which a computer program is stored, and the computer program is used for implementing the carrier initial phase determining method provided by the above various embodiments when being executed by a processor.
The readable storage medium may be a computer storage medium or a communication medium. Communication media includes any medium that facilitates transfer of a computer program from one place to another. Computer storage media can be any available media that can be accessed by a general purpose or special purpose computer. For example, a readable storage medium is coupled to a processor such that the processor can read information from, and write information to, the readable storage medium. Of course, the readable storage medium may also be an integral part of the processor. The processor and the readable storage medium may reside in an Application Specific Integrated Circuits (ASIC). Additionally, the ASIC may reside in user equipment. Of course, the processor and the readable storage medium may also reside as discrete components in a communication device. The readable storage medium may be a read-only memory (ROM), a random-access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.
The present invention also provides a program product comprising execution instructions stored in a readable storage medium. The at least one processor of the device may read the execution instructions from the readable storage medium, and the execution of the execution instructions by the at least one processor causes the device to implement the carrier initial phase determination method provided by the various embodiments described above.
In the above embodiments of the apparatus, it is understood that the Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the present invention may be embodied directly in a hardware processor, or in a combination of the hardware and software modules within the processor.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A method for determining an initial phase of a carrier, comprising:
receiving an initial time domain signal;
determining an LTF time domain signal based on the initial time domain signal;
determining m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, wherein the m non-zero subcarriers correspond to the m target channel phases one to one, and m is an integer;
and determining the initial phase of the carrier based on the m target channel phases corresponding to the m nonzero subcarriers.
2. The method for carrier initial phase determination of claim 1, wherein said determining an LTF time domain signal based on said initial time domain signal comprises:
and carrying out synchronous timing estimation on the initial time domain signal to obtain the LTF time domain signal.
3. The method for determining initial phase of carrier wave as claimed in claim 2, wherein said determining m target channel phases corresponding to m non-zero subcarriers based on said LTF time domain signal comprises:
sequentially carrying out frequency offset estimation and frequency offset compensation on the LTF time domain signal to obtain a frequency offset compensated LTF time domain signal; and determining m target channel phases corresponding to the m non-zero subcarriers based on the LTF time domain signal after the frequency offset compensation.
4. The method for determining initial phase of carrier wave according to claim 3, wherein said determining m target channel phases corresponding to the m non-zero subcarriers based on the LTF time domain signal after the frequency offset compensation comprises:
performing channel estimation on the LTF time domain signal after the frequency offset compensation to obtain m channel values corresponding to the m non-zero subcarriers, wherein the m non-zero subcarriers correspond to the m channel values one to one;
obtaining m phases corresponding to the m channel values to obtain m initial channel phases corresponding to the m non-zero subcarriers, wherein the m channel values correspond to the m phases and the m initial channel phases one to one;
and removing the phase rotation on the m initial channel phases to obtain the m target channel phases, wherein the m initial channel phases correspond to the m target channel phases one to one.
5. The method for determining initial carrier phase according to claim 4, wherein the determining initial carrier phase based on m target channel phases corresponding to the m non-zero subcarriers comprises:
and performing linear fitting on the m target channel phases to obtain the initial carrier phase.
6. The carrier initial phase determining method according to claim 5, wherein m is an even number greater than or equal to 2;
the performing linear fitting on the m target channel phases to obtain the initial carrier phase includes:
calculating the corresponding slopes of the m target channel phases; based on the slope and the m target channel phases, determining m/2 initial channel phases corresponding to zero subcarriers;
and calculating the average value of the m/2 initial channel phases to obtain a target channel phase corresponding to the zero subcarrier, and taking the target channel phase corresponding to the zero subcarrier as the initial phase of the carrier.
7. The method for determining initial phase of carrier wave according to claim 6, wherein said determining m/2 initial channel phases corresponding to zero subcarrier based on said slope and said m target channel phases comprises:
selecting two target channel phases corresponding to two symmetrical non-zero subcarriers from the m target channel phases, and determining a reference value based on the slope and the two target channel phases;
selecting m-2 target channel phases except the two target channel phases from the m target channel phases, and obtaining (m-2)/2 initial channel phases based on the m-2 target channel phases, the slope and the reference value;
and summarizing the reference value and the (m-2)/2 initial channel phases to obtain the m/2 initial channel phases.
8. A carrier initial phase determining apparatus, comprising:
a first signal receiving module, configured to receive an initial time domain signal;
a second signal determination module to determine an LTF time domain signal based on the initial time domain signal;
a channel phase determining module, configured to determine m target channel phases corresponding to m non-zero subcarriers based on the LTF time domain signal, where the m non-zero subcarriers correspond to the m target channel phases one to one, and m is an integer;
an initial phase determining module, configured to determine carrier initial phases based on m target channel phases corresponding to the m non-zero subcarriers.
9. A terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor when executing the computer program realizes the steps of the carrier initial phase determination method according to any one of claims 1 to 7.
10. A computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for initial phase determination of a carrier wave according to any one of claims 1 to 7.
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