CN112054983B - Signal amplitude processing method and device of OFDM receiver and terminal equipment - Google Patents

Signal amplitude processing method and device of OFDM receiver and terminal equipment Download PDF

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CN112054983B
CN112054983B CN202010854985.XA CN202010854985A CN112054983B CN 112054983 B CN112054983 B CN 112054983B CN 202010854985 A CN202010854985 A CN 202010854985A CN 112054983 B CN112054983 B CN 112054983B
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ofdm symbol
ofdm
power
domain
pilot
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CN112054983A (en
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吴昌强
朱安国
陈庚生
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TP Link Technologies Co Ltd
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TP Link Technologies Co Ltd
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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
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2673—Details of algorithms characterised by synchronisation parameters
    • H04L27/2675—Pilot or known symbols
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2681—Details of algorithms characterised by constraints
    • H04L27/2688—Resistance to perturbation, e.g. noise, interference or fading

Abstract

The invention discloses a signal amplitude processing method, a device and a terminal device of an OFDM receiver, wherein the method comprises the steps of screening out a first pilot frequency subcarrier set meeting a preset power threshold from OFDM symbols on a preamble domain, calculating the average power of the set and recording the position of each pilot frequency subcarrier in the set; and then calculating the power value of each OFDM symbol in the data domain according to the position of each pilot subcarrier in the first pilot subcarrier set, and finally performing power compensation on each OFDM symbol according to the average power and the power value of each OFDM symbol. The technical scheme of the invention screens out effective pilot frequency through the power threshold so as to resist frequency selection characteristics caused by multipath and MIMO fading channels and improve the accuracy of signal amplitude tracking and compensation.

Description

Signal amplitude processing method and device of OFDM receiver and terminal equipment
Technical Field
The present invention relates to the field of wireless communication technologies, and in particular, to a signal amplitude processing method and apparatus for an OFDM receiver, and a terminal device.
Background
In a communication system, amplitude distortion may occur during the process of transmitting and receiving packets due to the non-ideal characteristics of the hardware of the transmitter and the receiver, that is, there is a certain degree of inconsistency between the front and back power of signals during the duration of a packet. Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation system, and Error Vector Magnitude (EVM) is generally used in an OFDM receiver to measure the quality of a received signal. When the received signal has amplitude distortion in the time domain, if the amplitude distortion is not corrected, the EVM performance is greatly reduced, and the communication quality is also reduced.
In general, a typical OFDM communication system includes a preamble field for timing synchronization and channel estimation of signals and a data field for carrying user data. Some pilot frequency sub-carriers are inserted into specific sub-carrier positions of the frequency domain OFDM symbol, are known information of both transmitting and receiving sides, and can be used for carrying out carrier frequency offset, sampling clock offset, phase compensation and amplitude tracking. For the characteristics of the OFDM communication system, the prior art proposes to perform channel estimation using pilot or preamble in the frequency domain, and then compensate for the amplitude and phase, as in the application number: 201110144893.3. In addition, in the prior art, the power of a signal sampling point is counted in the time domain to obtain a power compensation coefficient, and then amplitude compensation is performed in the time domain, as described in application number: 201510543977 patent.
However, the prior art has the following defects: the first method needs to be subjected to complex channel estimation operation, does not consider channel fading distortion caused by multipath or Multiple-In Multiple-Out (MIMO for short) multi-antenna interference, and has high accuracy influenced by the channel fading distortion; the second type has certain limitations and is not suitable for the high-order OFDM modulation system. Because when high-order modulation is adopted, the average power of constellation points carried in different OFDM symbols in a transmitted signal is likely not in the same power plane, if the signal is directly forced to be compensated to the same power plane in a time domain in a receiver, amplitude distortion of the signal is artificially introduced at a baseband, and the performance of the receiver is further deteriorated.
Disclosure of Invention
The invention provides a signal amplitude processing method and device of an OFDM receiver and terminal equipment, which are suitable for each modulation mode and can improve the accuracy of signal amplitude tracking and compensation.
In order to solve the above technical problem, the present invention provides a signal amplitude processing method of an OFDM receiver, including:
preprocessing a signal received by an OFDM receiver to obtain an OFDM symbol of the received signal on a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols;
screening out a first pilot frequency subcarrier set meeting a preset power threshold according to OFDM symbols on a preamble domain, calculating the average power of the first pilot frequency subcarrier set, and recording the position of each pilot frequency subcarrier in the set;
extracting pilot data of each OFDM symbol in a data domain according to the position of each pilot subcarrier in the first pilot subcarrier set, and calculating a power value of each OFDM symbol in the data domain;
and performing power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
Further, the screening out a first pilot subcarrier set meeting a preset power threshold according to the OFDM symbol in the preamble domain specifically includes:
Finding a first OFDM symbol used for channel estimation in a preamble domain, and extracting a pilot frequency subcarrier in the first OFDM symbol;
and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
Further, the performing power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain specifically includes:
calculating a difference between the average power and a power value of each OFDM symbol in a data domain;
taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol;
or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
Further, the preprocessing is performed on the signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in the frequency domain, specifically:
performing synchronous processing on the signals received by the OFDM receiver to obtain the initial position of the received signals, the length of OFDM symbols and the length of cyclic prefixes of the OFDM symbols;
according to the initial position of the received signal, the length of the OFDM symbol and the length of the cyclic prefix of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion;
And performing fast Fourier transform on the signal after the serial-parallel conversion to obtain an OFDM symbol on a frequency domain.
Further, the method for processing the signal amplitude of the OFDM receiver further includes:
and performing amplitude correction on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
Correspondingly, the invention also provides a signal amplitude processing device of the OFDM receiver, which comprises: the device comprises a preprocessing module, a first calculating module, a second calculating module and a first executing module;
the preprocessing module is used for preprocessing the signal received by the OFDM receiver to obtain an OFDM symbol of the received signal on a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols;
the first calculation module is used for screening out a first pilot frequency subcarrier set meeting a preset power threshold according to the OFDM symbols on the preamble domain, calculating the average power of the first pilot frequency subcarrier set, and recording the position of each pilot frequency subcarrier in the set;
the second calculating module is configured to extract pilot data of each OFDM symbol in the data field according to a position of each pilot subcarrier in the first set of pilot subcarriers, and calculate a power value of each OFDM symbol in the data field;
The first execution module is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
Further, the first calculating module is configured to screen out a first pilot subcarrier set that meets a preset power threshold according to the OFDM symbol in the preamble domain, specifically:
the first calculation module finds a first OFDM symbol used for channel estimation in a preamble domain and extracts a pilot frequency subcarrier in the first OFDM symbol; and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
Further, the first executing module is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain, specifically:
the first execution module calculates a difference value between the average power and a power value of each OFDM symbol in a data domain; taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol; or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
Further, the preprocessing module is configured to preprocess a signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in a frequency domain, and specifically includes:
the preprocessing module carries out synchronous processing on the signals received by the OFDM receiver to obtain the initial position of the received signals, the length of OFDM symbols and the length of cyclic prefixes of the OFDM symbols;
according to the initial position of the received signal, the length of the OFDM symbol and the length of the cyclic prefix of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion;
and performing fast Fourier transform on the signals after the serial-parallel conversion to obtain OFDM symbols on a frequency domain.
Further, the signal amplitude processing apparatus of the OFDM receiver further includes: a second execution module;
and the second execution module is used for performing amplitude correction on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
Accordingly, the present invention also provides a terminal device comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the signal amplitude processing method of the OFDM receiver according to the present invention when executing the computer program.
Accordingly, the present invention also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program runs, the apparatus on which the computer-readable storage medium is located is controlled to execute the signal amplitude processing method of the OFDM receiver according to the present invention.
The embodiment of the invention has the following beneficial effects:
the invention provides a signal amplitude processing method, a device and a terminal device of an OFDM receiver, wherein the method comprises the steps of screening out a first pilot frequency subcarrier set meeting a preset power threshold from OFDM symbols on a preamble domain, calculating the average power of the set, and recording the position of each pilot frequency subcarrier in the set; and then calculating the power value of each OFDM symbol in the data domain according to the position of each pilot subcarrier in the first pilot subcarrier set, and finally performing power compensation on each OFDM symbol according to the average power and the power value of each OFDM symbol. Compared with the prior art, channel fading distortion caused by multipath or MIMO multi-antenna interference is not considered, the method screens out effective pilot frequency through the power threshold so as to resist frequency selection characteristics caused by multipath and MIMO fading channels and improve the accuracy of signal amplitude tracking and compensation; in addition, the invention only uses the received pilot frequency to carry out power statistics without carrying out channel estimation, thereby reducing the calculation complexity. In addition, the invention is suitable for all modulation modes from low order to high order, and has wide application range.
Drawings
FIG. 1 is a flow chart illustrating an embodiment of a power calibration warning method according to the present invention;
FIG. 2 is a schematic flow chart diagram illustrating another embodiment of a power calibration warning method according to the present invention;
FIG. 3 is a schematic diagram of a constellation obtained without amplitude tracking and compensation provided by the present invention;
FIG. 4 is a schematic diagram of a constellation obtained during amplitude tracking and compensation provided by the present invention;
fig. 5 is a schematic structural diagram of an embodiment of a signal amplitude processing apparatus of an OFDM receiver provided in the present invention;
fig. 6 is a schematic structural diagram of another embodiment of a signal amplitude processing apparatus of an OFDM receiver according to the present invention.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all 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.
Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a power calibration early warning method provided by the present invention, as shown in fig. 1, the method includes steps 101 to 104, and each step specifically includes the following steps:
Step 101: preprocessing a signal received by an OFDM receiver to obtain an OFDM symbol of the received signal on a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols.
In this embodiment, step 101 specifically includes:
carrying out synchronous processing on signals received by an OFDM receiver to obtain the initial position of the received signals, the length of OFDM symbols and the length of cyclic prefixes of the OFDM symbols;
according to the initial position of the received signal, the OFDM symbol length and the cyclic prefix length of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion;
and performing fast Fourier transform on the signals after the serial-parallel conversion to obtain OFDM symbols on a frequency domain.
In this embodiment, the receiver performs timing synchronization on the received signal to determine the start position T of the signal0Then according to the starting T0Cyclic Prefix (CP) length T of OFDM symbol length T, OFDMCPThe method comprises the steps of performing CP removing processing on a received signal, performing serial-to-parallel conversion, and finally performing Fast Fourier Transform (FFT) on the signal subjected to serial-to-parallel conversion to obtain an OFDM symbol in a frequency domain. The OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols.
In this embodiment, the CP removal processing and the serial-parallel conversion are not described herein again.
Step 102: screening out a first pilot frequency subcarrier set meeting a preset power threshold according to OFDM symbols on a preamble domain, calculating the average power of the first pilot frequency subcarrier set, and recording the position of each pilot frequency subcarrier in the set.
In this embodiment, the step 102 of "screening out the first pilot subcarrier set meeting the preset power threshold according to the OFDM symbol in the preamble field" specifically includes: finding a first OFDM symbol used for channel estimation in a preamble domain, and extracting a pilot frequency subcarrier in the first OFDM symbol; and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
Finding out the symbol for channel estimation in the symbol of the leading field, extracting the data of the pilot frequency sub-carrier wave, then making power judgment on each pilot frequency sub-carrier wave, and reserving the pilot frequency sub-carrier waves meeting the preset power threshold to form a first pilot frequency sub-carrier wave set.
In this embodiment, the power threshold may be selected by calculating a plurality of algorithms, such as counting the average power of all sub-carriers, comparing the power of each sub-carrier with the average power, and determining to reject the sub-carrier when the sub-carrier is smaller than a certain threshold range of the average power. In this case, the power threshold may be determined by multiplying the average power by a factor.
Assuming that the position of the initial pilot subcarrier is: { idx0,idx1,idx2,…,idxK-1And K represents the number of pilot subcarriers in the OFDM symbol. Meanwhile, in the received OFDM symbol for channel estimation in the preamble domain, the data on the pilot frequency subcarrier is assumed to be { P0,P1,P2,…,PK-1Step 102 is specifically:
pilot subcarrier power P ═ Pi|2，0≤i≤K-1；
By comparing the power P of the pilot sub-carriers with a power threshold PThrSelecting pilot frequency sub-carrier wave meeting preset power threshold, then accumulating power of the selected pilot frequency sub-carrier wave to obtainGet PSum。
Average power P of first set of pilot subcarriersTarget＝PSumAnd N is the total number of pilot frequency sub-carriers meeting the preset power threshold. Therefore, the position set of the pilot subcarriers satisfying the preset power threshold is Stidx＝{tidx0,tidx1,tidx2,…tidxN-1}。
Step 103: and extracting the pilot data of each OFDM symbol in the data domain according to the position of each pilot subcarrier in the first pilot subcarrier set, and calculating the power value of each OFDM symbol in the data domain.
In this embodiment, for the OFDM symbol in the data domain, the pilot data at the corresponding position is extracted according to the position of each pilot subcarrier, and the power value P of each pilot subcarrier is calculated according to the above methodd。
Step 104: each OFDM symbol in the data domain is power compensated based on the average power and the power value of each OFDM symbol in the data domain.
In this embodiment, step 104 specifically includes: calculating a difference between the average power and a power value of each OFDM symbol in the data domain; taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol;
or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
In the present embodiment, the power difference PΔ＝Pd/PTargetFor a real-time system with low time delay, the power difference value P calculated by each OFDM symbol of the data fieldΔAnd will be used as the power offset value for the next OFDM symbol. For systems that do not require real-time reception, the power difference P calculated for each OFDM symbol in the data fieldΔAnd may be used as the power compensation value of the current OFDM symbol.
Referring to fig. 2 as an example of this embodiment, fig. 2 is a schematic flowchart of another embodiment of a signal amplitude processing method of an OFDM receiver according to the present invention. Fig. 2 differs from fig. 1 in that the processing method further comprises step 205. Step 205: amplitude correction is performed for each OFDM symbol in the data domain based on the average power and the power value for each OFDM symbol in the data domain. The amplitude correction and the power compensation are simultaneously carried out, so that the robustness of amplitude tracking of the receiver can be improved.
In this example, the power difference P can be usedΔThe amplitude correction is performed on each OFDM symbol, and the correction can be performed according to the following formula:
Figure BDA0002643721810000081
wherein S (w) is an OFDM symbol in the received data field, and S' (w) is an OFDM symbol in the data field after amplitude correction.
To better illustrate the effect of the present invention, refer to fig. 3 and fig. 4, fig. 3 is a schematic diagram of a constellation obtained when amplitude tracking and compensation are not performed according to the present invention. Fig. 4 is a schematic diagram of a constellation obtained when amplitude tracking and compensation are performed according to the present invention. The horizontal axis coordinates of fig. 3 and fig. 4 are I and Q, respectively, which are general common modes of QAM modulation (i.e., input bits are mapped onto a complex plane to form complex modulation symbols), and are not described herein again. For a test signal with amplitude distortion, the EVM is-28.2 dB during signal analysis, as shown in fig. 3. After the method of the invention is adopted, the constellation diagram as shown in figure 4 is obtained, and the EVM of the constellation diagram is-41.8 dB. It can be known from the comparison between fig. 3 and fig. 4 that, after the amplitude tracking and compensation are performed by the method of the present invention, the whole receiving constellation point is close to the standard constellation point, and the demodulation performance is better.
In addition, in step 102 of the present invention, after the pilot subcarriers that do not satisfy the preset power threshold are removed, the problem of "a large error is generated when the frequency selectivity of the channel causes the frequency domain statistics of the power of the position of the pilot subcarriers of the OFDM symbols" can be avoided, thereby improving the accuracy of the power statistics and the robustness of the receiver for amplitude tracking.
Accordingly, referring to fig. 5, fig. 5 is a schematic structural diagram of an embodiment of a signal amplitude processing apparatus of an OFDM receiver according to the present invention. As shown in fig. 5, the apparatus includes: a preprocessing module 501, a first calculation module 502, a second calculation module 503, and a first execution module 504.
The preprocessing module 501 is configured to preprocess a signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols.
The first calculating module 502 is configured to screen out a first pilot subcarrier set meeting a preset power threshold according to the OFDM symbol in the preamble domain, calculate an average power of the first pilot subcarrier set, and record a position of each pilot subcarrier in the set.
The second calculating module 503 is configured to extract pilot data of each OFDM symbol in the data domain according to a position of each pilot subcarrier, and calculate a power value of each OFDM symbol in the data domain.
The first performing module 504 is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
The first calculating module 502 is configured to screen out a first pilot subcarrier set meeting a preset power threshold according to an OFDM symbol in a preamble domain, specifically: the first calculation module 502 finds a first OFDM symbol used for channel estimation in the preamble domain, and extracts a pilot subcarrier in the first OFDM symbol; and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
The first executing module 504 is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain, specifically: the first performing module 504 calculates a difference between the average power and the power value of each OFDM symbol in the data domain; taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol; or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
The preprocessing module 501 is configured to preprocess a signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in a frequency domain, specifically: the preprocessing module 501 performs synchronization processing on the signal received by the OFDM receiver to obtain the initial position of the received signal, the length of the OFDM symbol, and the length of the cyclic prefix of the OFDM symbol; according to the initial position of the received signal, the OFDM symbol length and the cyclic prefix length of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion; and performing fast Fourier transform on the signals after the serial-parallel conversion to obtain OFDM symbols on a frequency domain.
Referring to fig. 6 as an example of this embodiment, fig. 6 is a schematic structural diagram of another embodiment of a signal amplitude processing apparatus of an OFDM receiver according to the present invention. Fig. 6 differs from fig. 5 in that the apparatus further comprises: a second execution module 605. The second performing module 605 is configured to perform amplitude correction on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
The more operation principle and flow of the present device please join the signal amplitude processing method of the OFDM receiver described above.
Accordingly, an embodiment of the present invention further provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and capable of running on the processor, where the computer program, when executed by the processor, implements each process of the signal amplitude processing method embodiment of the OFDM receiver, and can achieve the same technical effect, and details are not repeated here to avoid repetition.
The terminal device can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. The terminal device may include, but is not limited to, a processor, a memory.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is the control center of the terminal device and connects the various parts of the whole terminal device using various interfaces and lines.
The memory may be used to store the computer program, and the processor may implement various functions of the terminal device by executing or executing the computer program stored in the memory and calling data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, etc. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
Wherein, the terminal device integrated module/unit can be stored in a computer readable storage medium if it is implemented in the form of software functional unit and sold or used as a stand-alone product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented.
In another embodiment of the present invention, a storage medium is provided, and the storage medium includes a stored computer program, wherein when the computer program runs, the storage medium is controlled to implement the signal amplitude processing method of the OFDM receiver according to any one of the above embodiments of the present invention.
In view of the above, the present invention provides a signal amplitude processing method, device and terminal device for an OFDM receiver, the method screens out a first pilot subcarrier set satisfying a preset power threshold from OFDM symbols on a preamble domain, calculates an average power of the set, and records the position of each pilot subcarrier; and then calculating the power value of each OFDM symbol in the data domain according to the position of each pilot frequency subcarrier, and finally performing power compensation on each OFDM symbol according to the average power and the power value of each OFDM symbol. Compared with the prior art, channel fading distortion caused by multipath or MIMO multi-antenna interference is not considered, the method screens out effective pilot frequency through the power threshold so as to resist frequency selection characteristics caused by multipath and MIMO fading channels and improve the accuracy of signal amplitude tracking and compensation; in addition, the invention only uses the received pilot frequency to carry out power statistics without carrying out channel estimation, thereby reducing the calculation complexity. In addition, the invention is suitable for all modulation modes from low order to high order, and has wide application range.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
It will be understood by those skilled in the art that all or part of the processes of the above embodiments may be implemented by hardware related to instructions of a computer program, and the computer program may be stored in a computer readable storage medium, and when executed, may include the processes of the above embodiments. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.

Claims (12)

1. A method for processing signal amplitude in an OFDM receiver, comprising:
preprocessing a signal received by an OFDM receiver to obtain an OFDM symbol of the received signal on a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols;
screening out a first pilot frequency subcarrier set meeting a preset power threshold according to OFDM symbols on a preamble domain, calculating the average power of the first pilot frequency subcarrier set, and recording the position of each pilot frequency subcarrier in the set;
Extracting pilot data of each OFDM symbol in a data domain according to the position of each pilot subcarrier in the first pilot subcarrier set, and calculating a power value of each OFDM symbol in the data domain;
and performing power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
2. The method for processing the signal amplitude of the OFDM receiver according to claim 1, wherein the screening, according to the OFDM symbol in the preamble domain, the first set of pilot subcarriers that satisfies the preset power threshold specifically includes:
finding a first OFDM symbol used for channel estimation in a preamble domain, and extracting a pilot frequency subcarrier in the first OFDM symbol;
and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
3. The method according to claim 1, wherein the power compensation is performed on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain, and specifically comprises:
calculating a difference between the average power and a power value of each OFDM symbol in a data domain;
Taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol;
or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
4. The method according to claim 1, wherein the pre-processing is performed on the signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in a frequency domain, and specifically comprises:
performing synchronization processing on the signals received by the OFDM receiver to obtain the initial position of the received signals, the length of OFDM symbols and the length of cyclic prefixes of the OFDM symbols;
according to the initial position of the received signal, the OFDM symbol length and the cyclic prefix length of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion;
and performing fast Fourier transform on the signals after the serial-parallel conversion to obtain OFDM symbols on a frequency domain.
5. The signal amplitude processing method of the OFDM receiver according to any one of claims 1 to 4, further comprising:
and performing amplitude correction on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
6. A signal amplitude processing apparatus of an OFDM receiver, comprising: the device comprises a preprocessing module, a first calculating module, a second calculating module and a first executing module;
the preprocessing module is used for preprocessing the signal received by the OFDM receiver to obtain an OFDM symbol of the received signal on a frequency domain; the OFDM symbols comprise preamble domain OFDM symbols and data domain OFDM symbols;
the first calculation module is used for screening out a first pilot frequency subcarrier set meeting a preset power threshold according to the OFDM symbols on the preamble domain, calculating the average power of the first pilot frequency subcarrier set, and recording the position of each pilot frequency subcarrier in the set;
the second calculating module is used for extracting pilot data of each OFDM symbol in a data domain according to the position of each pilot subcarrier in the first pilot subcarrier set and calculating the power value of each OFDM symbol in the data domain;
the first execution module is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
7. The apparatus of claim 6, wherein the first computing module is configured to select, according to the OFDM symbol in the preamble domain, a first pilot subcarrier set that meets a preset power threshold, specifically:
The first calculation module finds a first OFDM symbol used for channel estimation in a preamble domain and extracts a pilot frequency subcarrier in the first OFDM symbol; and screening a first pilot frequency subcarrier set meeting a preset power threshold from the extracted pilot frequency subcarriers.
8. The apparatus as claimed in claim 6, wherein the first performing module is configured to perform power compensation on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain, and specifically:
the first execution module calculates a difference value between the average power and a power value of each OFDM symbol in a data domain; taking the difference value corresponding to each OFDM symbol as the power compensation value of the next OFDM symbol; or, the difference value corresponding to each OFDM symbol is used as the power compensation value of the current OFDM symbol.
9. The apparatus of claim 6, wherein the preprocessing module is configured to preprocess the signal received by the OFDM receiver to obtain an OFDM symbol of the received signal in a frequency domain, and specifically:
the preprocessing module carries out synchronous processing on the signals received by the OFDM receiver to obtain the initial position of the received signals, the length of OFDM symbols and the length of cyclic prefixes of the OFDM symbols;
According to the initial position of the received signal, the OFDM symbol length and the cyclic prefix length of the OFDM symbol, removing the cyclic prefix of the received signal and performing serial-parallel conversion;
and performing fast Fourier transform on the signal after the serial-parallel conversion to obtain an OFDM symbol on a frequency domain.
10. The signal amplitude processing apparatus of the OFDM receiver according to any one of claims 6 to 9, further comprising: a second execution module;
and the second execution module is used for performing amplitude correction on each OFDM symbol in the data domain according to the average power and the power value of each OFDM symbol in the data domain.
11. A terminal device comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, the processor implementing a signal amplitude processing method of an OFDM receiver according to any one of claims 1 to 5 when executing the computer program.
12. A computer-readable storage medium, comprising a stored computer program, wherein the computer program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the signal amplitude processing method of the OFDM receiver according to any one of claims 1 to 5.
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