CN105162737A - Low-complexity self-adapting single carrier frequency domain equalization method and device for software radio system - Google Patents
Low-complexity self-adapting single carrier frequency domain equalization method and device for software radio system Download PDFInfo
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Abstract
The invention provides a low-complexity self-adapting single carrier frequency domain equalization method and device for a software radio system. The method comprises the steps of: S1: detecting valid data; S2: equalization initialization: storing a received signal vector to be equalized and an equalization coefficient matrix under reference conditions in a variable node storage block according to a certain storage mode, and initializing a channel mode and system parameters; S3: FFT operation: starting an FFT unit to convert a received sequence from the time domain into the frequency domain; S4: equalization process: starting a complex multiplication unit to carry out targeted frequency domain equalization processing; S5: IFFT operation: starting an IFFT unit to convert the output signal after the equalization processing from the frequency domain into the time domain; and S6: detection processing is completed: if the entire equalization process procedure is ended, using the result of the step S5 as the output signal of the entire device, otherwise, continuing to start from the step S3. The device is used for implementing the method. The method and the device provided by the invention have the advantages of reduced hardware complexity, excellent error rate performance, high resource utilization rate, good robustness, strong instantaneity, etc.
Description
Technical Field
The invention mainly relates to the field of wireless communication, in particular to a low-complexity self-adaptive single carrier frequency domain equalization method and device for a software radio system.
Background
In practical communication systems, the frequency band resource of the channel is often limited and deviates from the ideal characteristics, so that the signal passing through the channel generates linear distortion in the frequency domain, and the time domain waveform generates time dispersion effect, which introduces ISI. In addition, multipath effects in the wireless channel can also introduce ISI. Therefore, in a frequency selective fading channel under dynamic and multipath conditions, ISI and other factors have a very serious influence on system performance, and thus an effective equalization technique has become a key to design of a wireless communication system.
Key technologies currently widely adopted and effective against channel fading mainly include OFDM technology (OFDM stands for orthogonal frequency division multiplexing) and SC-FDE technology. The OFDM technology is an orthogonal multi-carrier modulation technology, converts a broadband frequency selective fading channel into a series of narrow-band flat fading channels, and has great advantages in overcoming ISI (inter-symbol interference) caused by multipath fading of the channels and realizing high-speed data transmission. However, the OFDM technology has the disadvantages of an excessively high peak-to-average power ratio, sensitivity to frequency offset, and the like, and causes the orthogonality between carriers to be easily destroyed in high-speed mobile communication, thereby generating adjacent channel interference and reducing system performance. The SC-FDE technology overcomes the disadvantages of the OFDM technology, and is more and more favored and concerned by people. The SC-FDE technology can be divided into two categories of single-carrier linear equalization technology and nonlinear equalization technology, wherein the single-carrier linear equalization technology mainly comprises ZF equalization technology, MMSE equalization technology and the like, the nonlinear equalization technology mainly comprises DFE technology and MLSE technology, the DFE represents decision feedback equalization, and the MLSE represents maximum likelihood sequence estimation.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the technical problems in the prior art, the invention provides a low-complexity self-adaptive single carrier frequency domain equalization method and device for a software radio system, which can reduce the hardware complexity, have excellent error rate performance, high resource utilization rate, good robustness and strong real-time performance.
In order to solve the technical problems, the invention adopts the following technical scheme:
a low-complexity self-adaptive single carrier frequency domain equalization method for a software radio system comprises the following steps:
s1: and (3) detecting valid data: if the accepting sequence is detected to be valid data, executing the step S2, otherwise, staying at the step S1 for waiting;
s2: equalization initialization: storing the received signal vector to be equalized and an equalization coefficient matrix under a reference condition into a variable node storage block according to a certain storage mode, and initializing a channel model and system parameters;
s3: FFT operation: starting an FFT unit to complete the conversion of a received sequence from a time domain to a frequency domain;
s4: and (3) equalization process: starting a complex multiplication unit, selecting an equalization coefficient matrix by a selector, and carrying out targeted frequency domain equalization processing;
s5: IFFT operation: starting an IFFT unit, and converting the output signal after equalization processing from a frequency domain to a time domain;
s6: and (3) finishing detection treatment: if the end of the whole equalization processing flow is detected, the result of the step S5 is used as an output signal of the whole device, otherwise, the execution is continued from the step S3.
As a further improvement of the process of the invention: in step S2, the frequency selective fading channel under the dynamic and classical city 6-path condition is adopted, and the path delays and normalized powers are 0(0.189), 1(0.379), 2(0.255), 8(0.090), 12(0.055), and 25 (0.032).
As a further improvement of the process of the invention: in step S2, a ZF linear equalization technique and an MMSE linear equalization technique in the SC-FDE technique are employed, and an adaptive equalization coefficient matrix is obtained by Matlab offline calculation.
As a further improvement of the process of the invention: in step S2, the number of the receiving/transmitting antennas of the system is 1, the length of the transmission data frame is 116424bits, the length of the CP is 25bits, and the number of the transmission data packets is 5000.
As a further improvement of the process of the invention: in step S2, the received signal vector to be equalized is obtained by the receiver sensor pre-processing the received signal vector and removing the CP; the CP is designed by adopting an SC-CPM signal data frame structure, wherein the SC-CPM represents serial cascade continuous phase modulation.
The present invention further provides an equalizing apparatus for implementing the above equalizing method, comprising:
the control unit is used for generating control signals of the whole module and carrying out time sequence control, and outputting time sequence control signals to the specific units at a certain moment by continuously monitoring internal output signals and processing completion marks of all the units so as to ensure that the control logic of all the functional units is accurate and effective;
the FFT unit is used for completing the conversion from the time domain to the frequency domain of the receiving sequence;
the equalization coefficient generating unit is used for generating equalization coefficients under different channel models and communication environments and by adopting different equalization technologies;
the complex multiplication unit comprises a selector and a complex multiplier and is used for completing complex multiplication and division operations of each functional unit, and the selector selects the equalization coefficient matrix to perform targeted frequency domain equalization;
and the IFFT unit is used for transforming the output signal after the equalization processing from the frequency domain to the time domain.
As a further improvement of the device of the invention: each local memory comprises a check node memory block and a variable node memory block to form a ping-pong buffer, only one memory block is in a balanced state at any time, and the other memory block is carrying out the call-in operation of the active intermediate variable set in the next period.
As a further improvement of the device of the invention: the control unit comprises a global clock counter, more than one local memory address counter, an FFT unit starting signal generator and an IFFT unit starting signal generator.
As a further improvement of the device of the invention: the FFT unit adopts a pipeline flow type I/O, and 1024 fixed-point data can be processed in each frame.
As a further improvement of the device of the invention: the IFFT unit adopts pipeline flow type I/O, and 1024 fixed-point data can be processed in each frame.
Compared with the prior art, the invention has the advantages that:
1. the invention relates to a low-complexity self-adaptive single carrier frequency domain equalization method and a device for a software radio system, which adopt an improved data frame structure design method, an SC-CPM parameter optimization method and a Laurent decomposition method of an M-system SC-CPM signal, greatly reduce the combinational logic area of an equalizer functional unit by using the method, simultaneously reduce the hardware realization complexity of an equalization device, and improve the frequency spectrum, the power utilization rate and the channel equalization efficiency.
2. The invention organically combines the SC-FDE technology and the SC-CPM technology, reduces the peak-to-average power ratio of signals to a certain extent, weakens the influence of factors such as ISI (inter-symbol interference) and the like, and greatly reduces the area overhead of an equalizing device.
3. The equalization coefficient generating unit is realized by Matlab off-line, so that part of complex addition, multiplication and division operations are saved, and the complexity and hardware cost of realization are greatly reduced.
4. The equalizer system parameters can be adaptively adjusted according to actual communication requirements, an optimal plan is made through the selector, the received signals are subjected to targeted frequency domain equalization, and the complex environment adaptive capacity and the system robustness are enhanced.
5. The invention is suitable for the equalization of SC-CPM signals, in particular to the equalization of SC-CPM signals in frequency selective fading channels under dynamic and multipath conditions, such as 32-state SC-CPM signals (M is 4, h is 1/4, 1RC frequency pulse forming) with code patterns of (25, 4) under the 6-path fading channels of the classical city. The equalizing method can obtain better compromise between average error rate performance and complexity, the equalizing device can be simultaneously suitable for ASIC realization and FPGA realization, and the equalizing device has the advantages of simple realization of an equalizing structure and a functional unit, optimized storage area and functional unit area and the like.
Drawings
Fig. 1 is a schematic diagram of a framework structure of a wireless communication system to which the present invention is applied.
FIG. 2 is a schematic flow diagram of the process of the present invention.
FIG. 3 is a block diagram of CPM module division in a specific application example of the present invention.
FIG. 4 is a diagram illustrating how CPM is combined with convolutional coding in an exemplary embodiment of the present invention.
FIG. 5 is a schematic diagram of the SCCC structure in an example embodiment of the invention.
FIG. 6 is a schematic diagram of an SC-CPM grid in an embodiment of the present invention.
Fig. 7 is a schematic diagram of a data frame structure design of an SC-CPM signal in a specific application example of the present invention.
Fig. 8 is a schematic diagram of the top level design of the functional units of the equalizing device of the present invention.
Fig. 9 is a schematic diagram of the equalizer of the present invention in a specific application example.
FIG. 10 is a schematic diagram of the average error rate performance of the SC-CPM signal and the conventional MSK signal when the invention is applied to the classic urban 6-path fading channel and the ZF/MMSE equalization technique is adopted.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples.
As shown in fig. 1 and fig. 2, the low complexity adaptive single carrier frequency domain equalization method for software radio system of the present invention comprises the following steps:
s1: detecting valid data;
if the accepting sequence is detected to be valid data, executing the step S2, otherwise, staying at the step S1 for waiting;
s2: carrying out balance initialization;
the initialization process comprises the steps of storing a received signal vector to be equalized and an equalization coefficient matrix (generated by Matlab offline in the process of solidifying the signal-to-noise ratio) under a reference condition into a variable node storage block according to a specific storage mode, and initializing a channel model and system parameters;
in a specific application example, a frequency selective fading channel under a dynamic and classical city 6-path condition can be selected, and the path delay and the normalized power are 0(0.189), 1(0.379), 2(0.255), 8(0.090), 12(0.055) and 25 (0.032); adopting two linear equalization techniques of SC-FDE technique, ZF/MMSE, obtaining a self-adaptive equalization coefficient matrix by Matlab offline calculation; the number of the receiving/transmitting antennas of the system is 1, the length of a transmitting data frame is 116424bits, the length of a CP is 25bits, and the number of transmitting data packets is 5000.
S3: performing FFT operation;
starting an FFT unit to complete the conversion of a received sequence from a time domain to a frequency domain;
assuming the channel is constant in each frame, the long delay spread multipath fading channel can be measured by:
the received signal may be expressed as:
the output of the pth matched filter is:
performing FFT operation on the above equation (3) can obtain:
Rk,p＝HkSk,p+Nk,p(4)
s4: a balancing process;
and starting a complex multiplication unit, optimizing an equalization coefficient matrix by a selector according to actual communication requirements, and performing targeted frequency domain equalization processing.
The ZF equalization technique is derived based on the peak distortion criterion. The peak distortion criterion may be defined as the minimization of the ISI performance index in the case where the equalizer output signal is least optimal. The impulse response function of a linear filter can be expressed as:
the ideal case for ISI cancellation is:
by z-transforming equation (6) above, we can get:
the MMSE equalization technique takes MMSE as a criterion. In order to make up for the deficiency of the ZF equalization technique, the MMSE equalization technique takes the influence of channel noise into full consideration, and selects a suitable tap coefficient to minimize the MSE of the system:
further, from the paswal theorem, it is possible to obtain:
the above equation is derived by taking the derivative to 0, and can result in:
after optimization, the equalization result can be expressed as:
S＝RWZF/MMSE(11)
s45: performing FFT operation;
starting an IFFT unit, and converting the output signal after equalization processing from a frequency domain to a time domain;
s6: the detection processing is finished;
if the end of the whole equalization processing flow is detected, the result of the step S5 is used as an output signal of the whole device, otherwise, the execution is continued from the step S3.
In the equalization process, SC-FDE represents single carrier frequency domain equalization, CP represents cyclic prefix, ZF represents zero forcing, MMSE represents minimum mean square error, ISI represents intersymbol interference, MSE represents mean square error, M representsDIs the maximum time delay of the channel, hlIs the amplitude of the first path, n (t) is the mean 0, variance σ2The complex white gaussian noise of (1) is, <math>
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</math> {qnis { w }nH andnconvolution of }, wnIs the equalization coefficient.
In a specific application example, the signal vector to be equalized received in the step 2 is obtained by preprocessing the received signal vector by the receiver sensor and removing the CP; the CP adopts a reasonable SC-CPM signal data frame structure design scheme to ensure the continuity of the SC-CPM signal phase; where SC-CPM denotes serial concatenated continuous phase modulation.
As shown in FIG. 7, the data length transmitted per frame is N in totalT＝N+NPWherein N isPThe length of the CP is larger than the maximum delay spread of the channel. In order to satisfy the continuity of the phase of the SC-CPM signal, there are:
wherein, the superscript l represents the l frame data, and the above formula can be equivalent to:
according to the characteristics of the CP,obviously, it is only necessary to guaranteeThis is true. Defining an accumulation term xin (l)Represents the sum of the phase states containing the first l-1 frame and the first n +1 symbols of the first frame, i.e.:
from the above formulas (13) and (14):
according to the characteristics of the CP, as (l)＝ap (l)Obviously, the above formula can be equivalent to:
the above formula shows that: the data frame structure of the SC-CPM signal is reasonably designed to meet the formula (16), so that the continuity of the phase of the SC-CPM signal can be ensured.
The invention adopts SC-CPM as the scheme of system signal selection, CPM is an advanced digital modulation technology widely adopted, the continuity of transmission phase enables the transmission phase to have higher frequency spectrum utilization rate, and the constant envelope of the transmitted signal enables the transmission phase to be insensitive to the nonlinearity of a transmitter power amplifier, so that the power utilization rate is higher. Based on the memory characteristic of the CPM signal and the recursion characteristic of the decomposition model, and in combination with an external SCCC and an interleaver, an SC-CPM system with excellent performance is formed.
Suppose that the M-ary symbol sequence to be transmitted is a ═ a0,a1,...,aNIn which a isiE { + -1, + -3., + - (M-1) }. The equivalent complex envelope model of the CPM signal can be expressed as:
wherein E issIs the symbol energy, TsIs the symbol period, phi0Is the initial phase of the carrier, so the normalized power baseband equivalent model of equation (17) can be expressed as:
s(t；a)＝exp{jΦ(t；a)}(18)
in the above equation, Φ (·) represents a time-varying phase function carrying information of the modulated signal, and its expression is:
wherein,for the modulation index (which may take a single value or a set of values that vary periodically), m, p are relatively prime positive integers, q (-) is a phase pulse shaping function, and the expression is:
where L is a positive integer, and represents the memory/association length of the CPM signal (per unit T)sAnd (c) and (d) are respectively set to 1 and 1, and are called a full-response CPM, and the other are called a partial-response CPM. g (-) is a function of the frequency pulse shaping, different g (-) willAffecting the phase smoothness of the transmitted signal.
At time interval nTs≤t≤(n+1)TsEquation (19) may be equivalent to:
at nTsTime of day, orderIndicates the phase state, { a ] when L ≠ 1n-1,an-2,...,an-L+1Denotes the relevant state, the state of the modulation signal can be expressed as:
sn＝{θn,an-1,an-2,...,an-L+1}(22)
the phase state transition of the CPM is time-varying, i.e. the phase change of the same input at two adjacent time instants is not the same. To construct a time invariant grid, simplifying the equalization process, a Rimoldi tilt phase is introduced:
Ψ(·)＝Φ(·)+πh(M-1)/Ts(23)
substituting formula (21) for formula (23), and reactingA new phase function expression can be obtained:
after introducing the Rimoldi tilt phase, the CPM can be divided into CPE, which stands for continuous phase encoder, and MMM, which stands for memoryless mapped modulator. Where the CPE performs a convolutional code-like operation on the data sequence, the MMM receives the values from the CPE registers and the input sequence and maps them to a specific phase signal.
However, the noise immunity of CPM alone is not ideal, and it is also necessary to further improve the average error rate performance of the system in a severe environment by combining with the convolutional coding technique. The SCCC technology integrates the advantages of the serial cascade code and the Turbo code, can well solve the error floor problem, can obtain high performance indexes through iterative decoding within a proper signal-to-noise ratio range, and expresses the serial cascade convolutional coding.
The main parameters of the SC-CPM are a modulation index h, a modulation system number M and a memory/association length L. The influence of each parameter on the performance of the wireless communication system conforms to the following rules: h is in direct proportion to the width of a main lobe of a frequency spectrum, but the influence on the width of a side lobe is small, so that the smaller h is, the higher the frequency spectrum utilization rate is; m determines the number of bits carried by each information symbol, and the larger M is, the higher the bit rate of information transmission is, but the larger the spectrum bandwidth is, so that the BER performance is reduced; increasing L can reduce the main lobe width of the spectrum appropriately, reduce the amplitude of the side lobe to a great extent, and improve the accuracy of channel equalization, but the computational complexity also rises sharply. The parameter optimization is to search M, h, L and g (·) to find out the optimal candidate value, and to reduce the computational complexity of the system to the maximum extent on the premise of ensuring the spectrum efficiency.
According to the Laurent theory, an M-ary single modulation index SC-CPM signal can be decomposed into a linear combination of P pulse amplitude modulation signals, so that frequency domain equalization processing can be performed by applying FFT operation.
Symbol sequence a to be transmittediE { ± (M-1) } may be expressed as a set of binary coefficients:
by bringing formula (25) into formula (18), it is possible to obtain:
wherein, <math>
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after introducing the Rimoldi tilt phase, the CPM can be divided into CPE and MMM, as shown in fig. 3-6. Where the CPE performs a convolutional code-like operation on the data sequence, the MMM receives the values from the CPE registers and the input sequence and maps them to a specific phase signal. However, the noise immunity of CPM alone is not ideal, and there is a need to further improve the flatness of wireless communication systems in harsh environments by combining convolutional coding techniquesThe average bit error rate performance. The SCCC technology integrates the advantages of the serial cascade code and the Turbo code, can well solve the error floor problem, and can obtain high performance index through iterative decoding within a proper SNR range. Information sequence BoThe code word sequence C is obtained after the processing of the outer encoderoAfter bit interleaving, the bit is input into an inner encoder to obtain an output code word sequence Bi. Thus, the SC-CPM signal is at time interval nTs≤t≤(n+1)TsThe phase state transition relationship.
As shown in fig. 8, the low complexity adaptive single carrier frequency domain equalization apparatus for software radio system of the present invention comprises:
the control unit is used for generating control signals of the whole module and carrying out time sequence control, and outputting time sequence control signals to the specific unit at a specific moment by continuously monitoring internal output signals and processing completion marks of each unit so as to ensure that the control logic of each functional unit is accurate and effective; it includes global clock counter, more than one local memory address counter, FFT unit start signal generator, IFFT unit start signal generator, as shown in fig. 8 (a);
an FFT unit, configured to perform time domain to frequency domain conversion on a received sequence, and perform pipeline streaming I/O, where 1024 fixed-point data may be processed per frame, as shown in fig. 8 (b);
the equalization coefficient generating unit is used for generating equalization coefficients under different channel models and communication environments and by adopting different equalization technologies, adaptively selecting applicable channel models and system parameters according to actual communication requirements, realizing by Matlab offline when the signal-to-noise ratio is solidified, and exporting and storing software data to a local memory corresponding to the equalization device to serve as an input signal of the complex multiplication unit;
a complex multiplication unit, including a selector and a complex multiplier, for completing the complex multiplication and division operations of each functional unit, and optimizing the equalization coefficient matrix by the selector to perform targeted frequency domain equalization processing, as shown in fig. 8 (c);
the IFFT unit is responsible for transforming the equalized output signal from the frequency domain to the time domain, and may process 1024 fixed-point data per frame by using pipeline streaming I/O, as shown in fig. 8 (d).
In a specific application example, each local memory comprises a check node storage block and a variable node storage block to form a ping-pong buffer, only one storage block is in a balanced state at any time, and the other storage block is carrying out calling operation of an active intermediate variable set in the next period.
Fig. 9 shows the top-level design of the external interface and internal interconnect of the present invention.
As shown in fig. 10, under a classical city 6-path fading channel model (TU6), SC-FDE is performed on an SC-CPM signal and an MSK signal widely used in a global system for mobile communications respectively by using two equalization techniques of MMSE and ZF, and average bit error rate performance is compared, where MSK represents minimum frequency shift keying. As can be seen from the figure: under TU6, the signal selection scheme can maximally improve the average error rate performance by 4dB compared with the conventional scheme, and the MMSE equalization technology can maximally improve the average error rate performance by 7dB compared with the ZF equalization technology.
In order to verify the correctness and effectiveness of the invention, the low-complexity adaptive single carrier frequency domain equalization device for the software radio system is realized on an FPGA (VERTEX5, XILINXCo.). The solidified signal-to-noise ratio is 10, a signal vector to be equalized and an optimal equalization coefficient matrix under a reference condition are generated by Matlab in an off-line mode, and the signal vector to be equalized and the optimal equalization coefficient matrix are stored into a local memory corresponding to the equalizing device at a specified moment by the FPGA. And respectively carrying out a time sequence simulation test based on a ModelsimSE-6410.1c environment on the control unit, the FFT unit, the complex multiplication unit and the IFFT unit. The FPGA output signals of all the functional units are compared and analyzed with the Matlab offline operation quantization result, and the errors are within 0.001%.
A time sequence simulation test based on a ModelsimSE-6410.1c environment is carried out on the top module, and 0.14248ms is consumed for completing the equalization processing of 1024 received data per frame when the global clock frequency is 40 MHz.
After the environment is synthesized based on XilinxISEDesignSuite14.7, the RTL-level circuit schematic diagram and hardware resource overhead statistics of the invention can be obtained.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.
Claims (10)
1. A low-complexity adaptive single carrier frequency domain equalization method for a software radio system is characterized by comprising the following steps:
s1: and (3) detecting valid data: if the accepting sequence is detected to be valid data, executing the step S2, otherwise, staying at the step S1 for waiting;
s2: equalization initialization: storing the received signal vector to be equalized and an equalization coefficient matrix under a reference condition into a variable node storage block according to a certain storage mode, and initializing a channel model and system parameters;
s3: FFT operation: starting an FFT unit to complete the conversion of a received sequence from a time domain to a frequency domain;
s4: and (3) equalization process: starting a complex multiplication unit, selecting an equalization coefficient matrix by a selector, and carrying out targeted frequency domain equalization processing;
s5: IFFT operation: starting an IFFT unit, and converting the output signal after equalization processing from a frequency domain to a time domain;
s6: and (3) finishing detection treatment: if the end of the whole equalization processing flow is detected, the result of the step S5 is used as an output signal of the whole device, otherwise, the execution is continued from the step S3.
2. The low complexity adaptive single carrier frequency domain equalization method for software defined radio system as claimed in claim 1 wherein in step S2, frequency selective fading channel under dynamic, classical city 6-path condition is adopted, and each path delay and normalized power are 0(0.189), 1(0.379), 2(0.255), 8(0.090), 12(0.055), 25 (0.032).
3. The low complexity adaptive single carrier frequency domain equalization method for software defined radio system as claimed in claim 1 wherein in step S2, the adaptive equalization coefficient matrix is obtained by Matlab offline calculation using ZF linear equalization technique and MMSE linear equalization technique in SC-FDE technique.
4. The low complexity adaptive single carrier frequency domain equalization method for software defined radio system as claimed in claim 3, wherein in step S2, the number of system transmitting/receiving antennas is 1, the length of the transmitted data frame is 116424bits, the length of CP is 25bits, and the number of transmitted data packets is 5000.
5. The low complexity adaptive single carrier frequency domain equalization method for software defined radio system of claim 1 wherein the received signal vector to be equalized is obtained by the receiver sensor preprocessing the received signal vector and removing the CP in step S2; the CP is designed by adopting an SC-CPM signal data frame structure, wherein the SC-CPM represents serial cascade continuous phase modulation.
6. An equalizing apparatus for implementing the equalizing method according to any one of claims 1 to 5, comprising:
the control unit is used for generating control signals of the whole module and carrying out time sequence control, and outputting time sequence control signals to the specific units at a certain moment by continuously monitoring internal output signals and processing completion marks of all the units so as to ensure that the control logic of all the functional units is accurate and effective;
the FFT unit is used for completing the conversion from the time domain to the frequency domain of the receiving sequence;
the equalization coefficient generating unit is used for generating equalization coefficients under different channel models and communication environments and by adopting different equalization technologies;
the complex multiplication unit comprises a selector and a complex multiplier and is used for completing complex multiplication and division operations of each functional unit, and the selector selects the equalization coefficient matrix to perform targeted frequency domain equalization;
and the IFFT unit is used for transforming the output signal after the equalization processing from the frequency domain to the time domain.
7. Equalizing device according to claim 6, characterized in that: each local memory comprises a check node memory block and a variable node memory block to form a ping-pong buffer, only one memory block is in a balanced state at any time, and the other memory block is carrying out the call-in operation of the active intermediate variable set in the next period.
8. Equalizing device according to claim 6, characterized in that: the control unit comprises a global clock counter, more than one local memory address counter, an FFT unit starting signal generator and an IFFT unit starting signal generator.
9. Equalizing device according to claim 6, characterized in that: the FFT unit adopts a pipeline flow type I/O, and 1024 fixed-point data can be processed in each frame.
10. Equalizing device according to claim 6, characterized in that: the IFFT unit adopts pipeline flow type I/O, and 1024 fixed-point data can be processed in each frame.
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