Signal processing method, system and equipment of receiver, medium and product

Abstract

The invention discloses a signal processing method, system and device of a receiver, a medium and a product, and belongs to the technical field of wireless communication technology. The method comprises the following steps: determining a frequency domain receiving signal of a base station, and initializing prior information; performing soft input and soft output equalization processing according to the frequency domain receiving signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain first external information; processing the first extrinsic information by using a soft input soft output channel decoder to obtain a decoding result and second extrinsic information; judging whether the decoding result generated last time is correct or not; if yes, outputting a decoding result generated last time; and if not, updating the prior information according to the second external information generated last time, and entering an iterative updating step. According to the invention, inter-symbol interference and inter-user interference can be suppressed in a multi-user-multiple-input-multiple-output system.

Description

Technical Field

[0001] This application relates to the field of wireless communication technologies, and in particular, to a signal processing method, system, device, medium, and product for a receiver. Background Art

[0002] With the rapid development of wireless communication technologies, the orthogonal frequency-division multiplexing (OFDM) technology has been widely applied due to its excellent performance in multipath propagation environments. However, its high peak-to-average power ratio (PAPR) has the negative impacts of increasing the power consumption of user terminals and reducing the system coverage ability. The uplink transmission in the LTE (Long Term Evolution) and 5GNR (5G New Radio) standard protocols adopts the single-carrier frequency-division multiple access (SC-FDMA) technology of discrete Fourier transform spread OFDM (DFT-s-OFDM) to achieve the purpose of reducing the peak-to-average ratio and improving the transmission efficiency of mobile user terminals.

[0003] However, in a multipath propagation environment, a single-carrier system will be affected by inter-symbol interference (ISI), resulting in a decline in receiving performance. In a multi-user multiple-input multiple-output (MU-MIMO) system, when the channels between users do not remain orthogonal, serious inter-user interference will also occur.

[0004] Therefore, how to suppress inter-symbol interference and inter-user interference in a multi-user multiple-input multiple-output system is a technical problem that those skilled in the art need to solve currently. Summary of the Invention

[0005] The purpose of this application is to provide a signal processing method, system, device, medium, and product for a receiver, which can suppress inter-symbol interference and inter-user interference in a multi-user multiple-input multiple-output system.

[0006] To solve the above technical problem, this application provides a signal processing method for a receiver, and the method includes:

[0007] Determine the frequency-domain received signal of the base station and initialize the prior information;

[0008] Perform soft-input and soft-output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain first external information;

[0009] Processing the first external information by using a soft-input and soft-output channel decoder to obtain a decoding result and a second external information;

[0010] Determine whether the most recently generated decoding result is correct;

[0011] If so, output the most recently generated decoding result;

[0012] If not, the prior information is updated according to the second external information generated most recently, and the step of performing soft input and soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information is entered.

[0013] Optionally, performing soft-input and soft-output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain the first external information includes:

[0014] Determining an estimated value of the equivalent frequency domain channel coefficient and an estimated value of the noise power;

[0015] Processing the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power and the prior information using a soft-input soft-output equalizer to obtain the first external information;

[0016] The process of the soft-input soft-output equalizer generating the first external information includes:

[0017] Converting the prior information into statistical information of a complex signal;

[0018] Performing frequency domain equalization processing according to the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power and the statistical information to obtain a first processing result; wherein the first processing result is an estimated value of the frequency domain signal after spectrum expansion processing;

[0019] Performing a combined estimation process on the first processing result in the frequency domain to obtain a second processing result; wherein the second processing result is a combined estimation value of the frequency domain signal;

[0020] Performing spectrum despreading processing and inverse time-frequency transform on the second processing result to obtain a third processing result;

[0021] adding a correction term to the third processing result to obtain a fourth processing result;

[0022] The first external information is calculated according to the fourth processing result.

[0023] Optionally, perform a combined estimation process on the first processing result in the frequency domain to obtain a second processing result, including:

[0024] Determine the signal-to-noise ratio of each subcarrier in the first processing result, and calculate the weighting coefficient of each subcarrier using the signal-to-noise ratio;

[0025] Perform a combined estimation operation on the first processing result in the frequency domain using the weighting coefficient to obtain the second processing result.

[0026] Optionally, calculate the first extrinsic information according to the fourth processing result, including:

[0027] Convert the fourth processing result into an orthogonal amplitude modulation symbol estimate value;

[0028] Calculate the first extrinsic information using the orthogonal amplitude modulation symbol estimate value.

[0029] Optionally, process the first extrinsic information using a soft input soft output channel decoder, including:

[0030] Perform a descrambling operation, a deinterleaving operation, and a rate matching operation on the first extrinsic information to obtain a fifth processing result;

[0031] Input the fifth processing result into the soft input soft output channel decoder.

[0032] Optionally, after updating the prior information according to the second extrinsic information generated most recently, further include:

[0033] Update the iteration count;

[0034] Correspondingly, before determining whether the decoding result generated most recently is correct, further include:

[0035] Determine whether the iteration count is greater than a preset value;

[0036] If so, output the decoding result generated most recently.

[0037] Optionally, update the prior information according to the second extrinsic information generated most recently, including:

[0038] Perform a rate matching operation, an interleaving operation, and a scrambling operation on the second extrinsic information to obtain a sixth processing result;

[0039] Update the prior information to the sixth processing result.

[0040] This application also provides a signal processing system for a receiver, the system includes:

[0041] A receiving module, configured to determine the frequency-domain received signal of a base station;

[0042] A priori information setting module, configured to initialize the a priori information;

[0043] An equalization processing module, configured to perform soft-input soft-output equalization processing according to the frequency-domain received signal, the equivalent frequency-domain channel coefficient, the noise power, and the a priori information to obtain a first extrinsic information;

[0044] A decoding module, configured to process the first extrinsic information by using a soft-input soft-output channel decoder to obtain a decoding result and a second extrinsic information;

[0045] A judgment module, configured to judge whether the most recently generated decoding result is correct; if so, output the most recently generated decoding result; if not, update the a priori information according to the most recently generated second extrinsic information, and enter the step of performing soft-input soft-output equalization processing according to the frequency-domain received signal, the equivalent frequency-domain channel coefficient, the noise power, and the a priori information.

[0046] This application also provides a storage medium, on which a computer program is stored, and when the computer program is executed, the steps performed by the signal processing method of the above receiver are implemented.

[0047] This application also provides an electronic device, including a memory and a processor, where a computer program is stored in the memory, and when the processor calls the computer program in the memory, the steps performed by the signal processing method of the above receiver are implemented.

[0048] This application also provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, the steps performed by the signal processing method of the above receiver are implemented.

[0049] This application initializes the a priori information before the first iteration, performs soft-input soft-output equalization processing according to the frequency-domain received signal, the equivalent frequency-domain channel coefficient, the noise power, and the a priori information to obtain a first extrinsic information; processes the first extrinsic information by using a soft-input soft-output channel decoder to obtain a decoding result and a second extrinsic information; if the decoding result is correct, it is output, and if the decoding result is incorrect, the a priori information is updated according to the most recently generated second extrinsic information and the soft-input soft-output equalization processing is iteratively performed. The above solution continuously updates the a priori information and the extrinsic information during the iteration process, thereby effectively reducing the influence of interference and improving the communication quality of the system. Therefore, this application can suppress inter-symbol interference and inter-user interference in a multi-user multiple-input multiple-output system. This application also provides a signal processing system of a receiver, a storage medium, an electronic device, and a computer program product, which have the above beneficial effects and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] To more clearly illustrate the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 It is a flowchart of a signal processing method for a receiver provided by an embodiment of the present application;

[0052] Figure 2 It is a schematic diagram of uplink transmission in a MU-MIMO communication system provided by an embodiment of the present application;

[0053] Figure 3 It is a flowchart of bit-level data processing provided by an embodiment of the present application;

[0054] Figure 4 It is a flowchart of generating a transmission signal for a user terminal based on OQAM modulation provided by an embodiment of the present application;

[0055] Figure 5 It is a schematic diagram of conjugate symmetric extension provided by an embodiment of the present application;

[0056] Figure 6 It is a general processing flowchart of a Turbo receiver on the base station side provided by an embodiment of the present application;

[0057] Figure 7 It is a processing flowchart of a soft input soft output channel equalizer provided by an embodiment of the present application;

[0058] Figure 8 It is a schematic diagram of the implementation principle of a computer program product provided by an embodiment of the present application;

[0059] Figure 9 It is a schematic diagram of BLER performance comparison when MCS is 2 provided by an embodiment of the present application;

[0060] Figure 10 It is a schematic diagram of BLER performance comparison when MCS is 7 provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the scope of protection of this application.

[0062] Please refer to the following Figure 1 , Figure 1 , which is a flowchart of a signal processing method for a receiver provided in an embodiment of this application.

[0063] The specific steps may include:

[0064] S101: Determine the frequency-domain received signal of the base station and initialize the prior information;

[0065] Among them, this embodiment can be applied to a receiver in a multi-user multiple-input multiple-output (MU-MIMO) system, and the receiver is a Turbo receiver in the MU-MIMO system. A Turbo receiver refers to a receiver that uses Turbo equalization technology to implement signal reception and processing. The Turbo equalization technology is an equalization technology based on iteration and soft input soft output. Specifically, this application can be used for the uplink Turbo receiver of a single-carrier frequency-division multiple access (SC-FDMA) system based on FDSS-SE (frequency-domain spectrum shaping with spectrum expansion). Currently, the mainstream implementation methods of SC-FDMA include: based on DFT-s-OFDM (discrete Fourier transform spread orthogonal frequency-division multiplexing) and CP-OQAM-OFDM (orthogonal frequency-division multiplexing based on offset quadrature amplitude modulation with cyclic prefix). Different SC-FDMA implementation methods correspond to different implementation methods of FDSS-SE used.

[0066] The multi-user multiple-input multiple-output system is the MU-MIMO communication system. Please refer to Figure 2 , Figure 2 , which is a schematic diagram of the uplink transmission of an MU-MIMO communication system provided in an embodiment of this application. In the MU-MIMO communication system, a base station with M antennas and U single-antenna users are deployed. , , …, represents the signal sent by the single-antenna user, represents the serial number of the OFDM symbol, , , …, represents the channel coefficient, , represents the m-th antenna of the base station at the the received signal on an OFDM symbol denotes the noise vector, and u denotes the serial number of the user.

[0067] During uplink transmission, each user can send signals to the base station on the same time-frequency resources. The base station with multiple antennas receives the superimposed and noisy received data after the signals sent by each user terminal are transmitted through the channel. The base station completes signal detection and other processing based on the received signals.

[0068] The above frequency-domain received signal is the received signal at the base station after being transmitted through the channel. The receiver can use prior information to assist the signal decoding process and improve the decoding accuracy. The prior information is the estimation of the prior probability of each bit during the decoding process. The prior information in this embodiment is the information corresponding to the user's transmitted signal. Before the first iteration, since no channel decoding process has been performed on the received signal, the log-likelihood ratio of the bit sequence of each user's transmitted signal can be set to 0 as the prior information.

[0069] S102: Perform soft input soft output equalization processing according to the frequency-domain received signal, equivalent frequency-domain channel coefficient, noise power, and the prior information to obtain the first extrinsic information;

[0070] Among them, in this step, the receiver uses the frequency-domain received signal, equivalent frequency-domain channel coefficient, noise power, and prior information to perform soft input soft output (SISO) equalization processing to accurately estimate the transmitted data and suppress inter-symbol interference and inter-user interference. Considering the FDSS-SE technology, in the SISO equalizer, combined estimation processing is performed on the frequency-domain signal after spectrum spreading to improve the estimation accuracy of the spectrum-spread frequency-domain signal, and thus achieve the effect of improving the accuracy of the final output result of the SISO equalizer. The soft input soft output equalizer can output the log-likelihood ratio of each bit, that is, the first extrinsic information, by considering the statistical characteristics of the user's transmitted signal and the influence of the channel, which reflects the reliability of the estimation of each bit. The above first extrinsic information can participate in the channel decoding process in subsequent steps to improve the accuracy of data demodulation.

[0071] S103: Use a soft input soft output channel decoder to process the first extrinsic information to obtain a decoding result and a second extrinsic information;

[0072] Among them, this step uses a soft input soft output channel decoder to decode the received first extrinsic information. The soft input soft output channel decoder considers the uncertainty of the received signal during the decoding process and continuously updates the log-likelihood ratio of each bit through iterative calculation, so as to obtain a more accurate decoding result and a second extrinsic information.

[0073] S104: Determine whether the most recently generated decoding result is correct; if yes, proceed to step S105; if no, proceed to step S106;

[0074] Among them, after obtaining the decoding result, it is possible to determine whether the most recently generated decoding result is correct. Specifically, in this step, it is possible to determine whether the decoding result is correct based on the cyclic redundancy check code, or to determine whether the decoding result is correct according to the decoding results generated in the most recent two times (if they are the same, it is correct; if they are different, it is incorrect). If the decoding result is correct, output the most recently generated decoding result; if the decoding result is incorrect, perform iteration to regenerate the decoding result and the second extrinsic information.

[0075] S105: Output the most recently generated decoding result;

[0076] S106: Update the prior information according to the most recently generated second extrinsic information, and proceed to step S102.

[0077] Among them, this step is based on the premise that the most recently generated decoding result is incorrect. At this time, the prior information can be updated according to the most recently generated second extrinsic information, and proceed to the step of performing soft input soft output equalization processing according to the frequency domain received signal, equivalent frequency domain channel coefficient, noise power, and the prior information, so as to use the latest decoding result to improve the decoding quality in the next iteration.

[0078] As a feasible implementation manner, after updating the prior information according to the most recently generated second extrinsic information, the iteration count can also be updated; correspondingly, before determining whether the most recently generated decoding result is correct, it is also possible to determine whether the iteration count is greater than a preset value; if yes, output the most recently generated decoding result; if no, proceed to the step of determining whether the most recently generated decoding result is correct.

[0079] In this embodiment, the prior information is initialized before the first iteration, soft input soft output equalization processing is performed according to the frequency domain received signal, equivalent frequency domain channel coefficient, noise power, and the prior information to obtain the first extrinsic information; the soft input soft output channel decoder is used to process the first extrinsic information to obtain the decoding result and the second extrinsic information; if the decoding result is correct, it is output, if the decoding result is incorrect, the prior information is updated according to the most recently generated second extrinsic information and iteration is performed for soft input soft output equalization processing. The above solution continuously updates the prior information and the extrinsic information during the iteration process, thereby effectively reducing the influence of interference and improving the communication quality of the system. Therefore, this embodiment can suppress inter-symbol interference and inter-user interference in a multi-user multiple-input multiple-output system.

[0080] The following introduces the process of generating the transmission signal of the user terminal:

[0081] Let represent the binary bit data to be transmitted by the th user to the base station. represents the data in the binary bit data , and the length of the bit data is , where .

[0082] Please refer to Figure 3 , Figure 3 which is a flowchart of bit-level data processing provided by an embodiment of this application. The binary bit data undergoes a channel coding operation to obtain a codeword . The codeword undergoes rate matching, interleaving, and scrambling operations to obtain a processing result . The processing result is modulated to obtain a symbol . The symbol is block-operated to obtain symbol data .

[0083] Due to different implementation methods of SC-FDMA, Figure 3 there are two corresponding implementation methods for the modulation process in . When SC-FDMA is implemented based on CP-OQAM-OFDM, the modulation process is as follows: First, the processing result is modulated by QAM (Quadrature Amplitude Modulation) to obtain a complex QAM symbol , and then the complex QAM symbol is transformed by OQAM (Offset Quadrature Amplitude Modulation) to obtain a real OQAM symbol . When SC-FDMA is implemented based on DFT-s-OFDM, the modulation process is directly: The processing result is modulated by QAM (Quadrature Amplitude Modulation) to obtain a complex QAM symbol

[0084] Figure 3 shows the processing flow of converting the bit data of the th user terminal into a complex signal, which specifically includes the following steps:

[0085] Step A1: The bit data Encoded into a codeword by a channel encoder (such as LDPC code, Turbo code, etc.) , represents the data in the codeword , where represents the th user's code block length after encoding of bit data.

[0086] Step A2: Perform operations such as rate matching, interleaving, and scrambling on the codeword to obtain a processing result , , and , represents operations such as rate matching, interleaving, and scrambling. and respectively represent the QAM modulation order of the th user (for example, when using QPSK modulation = 2) and the number of QAM symbols. represents the vector composed of the th bits in the i-th group. represents the length of the data bits after rate matching processing.

[0087] Step A3: Map according to the implementation method of SC - FDMA. The specific process is as follows:

[0088] If SC - FDMA is implemented based on CP - OQAM - OFDM, then map to complex QAM symbols and further transform them into real OQAM symbols : , where and respectively represent the operations of taking the real part and the imaginary part. represents the data in the QAM symbol , represents the data in the real OQAM symbol .

[0089] If SC - FDMA is implemented based on DFT - s - OFDM, map to complex QAM symbols .

[0090] Step A4: Allocate the symbols to L OFDM symbols. The specific allocation method is described separately according to different implementation methods of SC - FDMA:

[0091] If SC - FDMA is implemented based on CP - OQAM - OFDM, then allocate the OQAM symbols Allocated to L OFDM symbols, the th user has complex QAM symbols within each OFDM symbol, that is, 2 real OQAM symbols. Let the real OQAM symbol represent the th user's th OQAM symbol data in the th OFDM symbol, where , .

[0092] If SC - FDMA is implemented based on DFT - s - OFDM, then the QAM symbols are allocated to L OFDM symbols, and the th user has complex QAM symbols within each OFDM symbol. Let the complex QAM symbol represent the th user's th QAM symbol data in the th OFDM symbol, where , .

[0093] Based on the above conversion process from bit data to symbols , the following further shows the process of the user terminal generating the final transmitted signal: performing time - frequency transformation on the symbol to obtain the frequency - domain signal , performing frequency - domain transmit processing FDTP (Frequency Domain Transmit Processing) on the frequency - domain signal to obtain the frequency - domain transmitted signal , performing - point IFFT processing on the frequency - domain transmitted signal to obtain the time - domain transmitted signal , and inserting CP (Cyclic Prefix) into the time - domain transmitted signal to obtain the transmitted signal.

[0094] The process of performing frequency - domain transmit processing on the frequency - domain signal to obtain the frequency - domain transmitted signal is as follows: performing spectrum spreading on the frequency - domain signal to obtain the spectrum - spreading result , performing frequency - domain spectrum shaping on the spectrum - spreading result to obtain the frequency - domain spectrum - shaping result , and performing Perform subcarrier mapping to obtain the frequency-domain transmission signal .

[0095] Please refer to Figure 4 , Figure 4 , which is the flowchart for generating the transmission signal of the user terminal in the SC-FDMA system provided by the embodiment of the present application. The processing flow for generating the transmission signal of the th user terminal includes the following steps:

[0096] Step B1: Perform time-frequency transformation on the symbol to obtain the frequency-domain signal . Different methods are adopted for the time-frequency transformation for different SC-FDMA implementation methods.

[0097] When SC-FDMA is implemented based on CP-OQAM-OFDM, the real OQAM symbol is passed through -point generalized DFT (GDFT) to obtain the frequency-domain signal , where the th element of the GDFT matrix is , e represents the natural constant, T represents the transpose, represents the imaginary unit, represents the data in the real OQAM symbol . N represents the number of points of the generalized DFT. Here, N takes the value of 2 ;

[0098] When SC-FDMA is implemented based on DFT-s-OFDM, the complex QAM symbol is passed through -point DFT to obtain the frequency-domain signal , where the th element of the DFT matrix is , represents the data in the complex QAM symbol . N represents the number of points of the DFT. Here, N takes the value of .

[0099] Step B2: Perform frequency-domain transmit processing (FDTP) on to obtain the processed frequency-domain transmission signal . FDTP includes two items, namely FDSS-SE processing and subcarrier mapping. Among them, FDSS-SE includes two sub-processing flows: spectrum spreading and frequency-domain spectrum shaping. Therefore, step B2 can be divided into three sub-steps B21 - B23:

[0100] Step B21: For perform spectrum spreading processing to obtain a spectrum spreading result , and the following different methods are adopted for the spectrum spreading of different SC-FDMA implementation manners:

[0101] If SC-FDMA is implemented based on CP-OQAM-OFDM, the spectrum spreading adopts conjugate symmetric spreading processing: , It can be expressed as:

[0102] ;

[0103] denotes the transpose operation, denotes the conjugate operation, and the preset parameter , and denotes the roll-off factor in the FDSS-SE processing of the th user, denotes the -th element of the frequency-domain signal obtained after GDFT processing, denotes the -th element of the frequency-domain signal obtained after GDFT processing. The conjugate of the -th user occupies subcarriers after FDSS-SE processing.

[0104] Please refer to Figure 5 , Figure 5 which is a schematic diagram of conjugate symmetric spreading provided by an embodiment of the present application. The figure shows the process of copying the first elements of the frequency-domain signal, reversing them in conjugate order to obtain the conjugate symmetric spreading result .

[0105] When SC-FDMA is implemented based on DFT-s-OFDM, the spectrum spreading adopts symmetric spreading processing: , where the preset parameter , and denotes the roll-off factor in the FDSS-SE processing of the th user, denotes the -th element of the frequency-domain signal obtained after DFT processing. The th user occupies subcarriers after FDSS-SE processing.

[0106] Step B22: Perform frequency-domain spectrum shaping processing to obtain the frequency-domain spectrum shaping result :

[0107] ;

[0108] The above formula can be expressed as: ; represents the data in the frequency-domain spectrum shaping result .

[0109] Among them, represents the shaping filter coefficient used by the th user in the FDSS processing

[0110] Step B23: The subcarrier mapping process is to map the frequency-domain signal of the th user to the allocated frequency-domain resources to obtain the frequency-domain signal . The elements in the frequency-domain signal that are not mapped by are set to 0

[0111] Step B3: By performing traditional -point IFFT processing on the frequency-domain signal , generate the time-domain transmission signal , where represents the total number of subcarriers in an OFDM symbol in the system, and there is .

[0112] The following introduces the working process of the Turbo receiver on the base station side

[0113] The solution of this embodiment is for a MU-MIMO system that combines FDSS-SE and SC-FDMA single-carrier technologies, and designs a Turbo receiver that effectively utilizes the signals in the extended spectrum part for uplink transmission. When receiving on the base station side, there will be interference between the symbols of the user itself and also interference between the symbols of different users, and these transmitted symbols are all the target values to be estimated during the equalization at the receiving end. If there is prior information about the transmitted symbols available during the equalization process, the interference between symbols and between users can be reduced during the equalization process. After completing the preliminary frequency-domain equalization, based on the effective signal-to-noise ratio on different subcarriers, combined estimation processing is performed on the frequency-domain symbol estimation to achieve the purpose of fully utilizing the signals on the extended frequency band to improve the receiving performance. For the preliminary symbol estimation obtained after the frequency-domain combination processing, in order to meet the Turbo principle and obtain the Turbo iteration gain, this embodiment derives and designs a calculation method for the Turbo principle correction term. For the above-mentioned corrected symbol estimation, in order to obtain the Turbo iteration gain, this embodiment derives and designs a calculation method for the extrinsic information output by the equalizer

[0114] Since the Turbo receiver in this embodiment is designed to derive the calculation method of the extrinsic information of the SISO equalizer under the condition of combined estimation processing for frequency-domain symbols, frequency diversity gain and iterative gain can be obtained simultaneously. The frequency diversity gain comes from the combined estimation processing of frequency-domain symbols. By combining and estimating the extended-band signals, the accuracy of the equalizer estimation is improved, and further the gain is brought by improving the accuracy of the decoder. The iterative gain comes from the second extrinsic information fed back from the channel decoder to the equalizer. Since the channel decoder has error correction ability, feeding the second extrinsic information output by the channel decoder back to the equalizer as the prior information can convert the gain brought by the error correction of the channel decoder into a more accurate prior estimation of the transmitted signal by the equalizer. Then, in the subsequent iterative equalization process, the iterative gain can be brought by interference cancellation based on the prior information.

[0115] In the MU-MIMO scenario, the frequency-domain resources allocated to different users may not be exactly the same. Specifically, for a single subcarrier, the corresponding number of users may be less than . This embodiment defines the number of users corresponding to the th subcarrier as , where , and . When , it means that no user uses the th subcarrier to transmit signals. Therefore, the receiver can not perform reception processing on this subcarrier. For the convenience of representation, this embodiment represents the true serial number of the th user corresponding to the th subcarrier as , where . To represent the mapping relationship between the subcarrier serial numbers in the system and the subcarriers actually occupied by the th user, this embodiment uses to represent the serial number of the th subcarrier within the th subcarrier actually occupied by the th user.

[0116] Let represent the frequency-domain channel coefficient between the th OFDM symbol, the th subcarrier, and the antennas of the base station and the single-antenna users, with a dimension of . Let represent the frequency-domain received signal of the base station on the th OFDM symbol and the th subcarrier, with a dimension of Then the received signal in the frequency domain can be expressed as:

[0117] ;

[0118] wherein, represents a vector composed of the frequency-domain transmitted signals after spectrum spreading processing of users on the th subcarrier, and the dimension is . It should be noted that and only differ in that the former forms a frequency-domain signal according to subcarriers, and the latter forms a frequency-domain signal according to users. Essentially, they represent the same signal, that is, both represent the frequency-domain signal obtained after spectrum spreading processing. represents a diagonal matrix composed of the FDSS shaping filter coefficients of users on the th subcarrier, and the dimension is . represents an operation of converting a vector into a diagonal matrix. is a noise vector, and the dimension is , and the variance of each element is . represents the FDSS shaping filter coefficient of the 0th user on the nth subcarrier.

[0119] For the sake of convenient representation, let represent the equivalent frequency-domain channel coefficient including the FDSS shaping filter coefficient, where represents the th subcarrier corresponding to the th user's channel coefficient vector. Then the received signal in the frequency domain can be expressed as:

[0120] ;

[0121] The base station completes processing such as channel equalization and channel decoding based on the received signals on each OFDM symbol and each subcarrier .

[0122] Please refer to Figure 6 , Figure 6 which is the overall processing flow chart of a Turbo receiver on the base station side provided by the embodiment of the present application. The process of the Turbo receiver completing the processing of the received signal through iterative processing includes: inputting the estimated values of the equivalent frequency-domain channel coefficient and the noise power , the prior information, and the received signal in the frequency domain , the soft input soft output equalizer generates a processing result , for the processing result perform descrambling operation, deinterleaving operation and rate matching operation to obtain a processing result , input the processing result into the soft input soft output channel decoder to obtain a decoding result and extrinsic information . Determine whether the decoding result is correct or reaches the maximum number of iterations; if so, output the decoding result, otherwise perform rate matching, interleaving, and scrambling operations on the extrinsic information to obtain new prior information for the next iteration.

[0123] The processing flow chart of the Turbo receiver includes the following steps:

[0124] Step C1: Initialize the prior information before the first iteration, that is, initialize the log-likelihood ratio of the corresponding bit sequence to 0 as the prior information.

[0125] Step C2: Based on the frequency-domain received signal , the estimated value of the equivalent frequency-domain channel coefficient and the noise power estimates, prior information perform soft input soft output (Soft-In-Soft-Out, SISO) equalization processing, and output the extrinsic information of each user .

[0126] In this embodiment, the extrinsic information generated by the soft input soft output equalizer is referred to as the first extrinsic information. The process of generating the above first extrinsic information specifically includes: determining the estimated value of the equivalent frequency-domain channel coefficient and the estimated value of the noise power; using the soft input soft output equalizer to process the frequency-domain received signal, the estimated value of the equivalent frequency-domain channel coefficient, the estimated value of the noise power, and the prior information to obtain the first extrinsic information;

[0127] Among them, the process of the soft input soft output equalizer generating the first extrinsic information (that is, using the soft input soft output equalizer to process the frequency-domain received signal, the estimated value of the equivalent frequency-domain channel coefficient, the estimated value of the noise power, and the prior information) includes:

[0128] Step C21: Convert the prior information into statistical information of complex signals;

[0129] Step C22: Perform frequency-domain equalization processing based on the frequency-domain received signal, the estimated value of the equivalent frequency-domain channel coefficient, the estimated value of the noise power, and the statistical information to obtain a first processing result; wherein, the first processing result is the estimated value of the frequency-domain signal after spectrum spreading processing;

[0130] Step C23: Perform combined estimation processing on the first processing result in the frequency domain to obtain a second processing result;

[0131] Wherein, the second processing result is the combined estimated value of the frequency-domain signal; specifically, in this step, the signal-to-noise ratio of each subcarrier in the first processing result can be determined, and the weighting coefficient of each subcarrier can be calculated using the signal-to-noise ratio; the combined estimation operation in the frequency domain is performed on the first processing result using the weighting coefficient to obtain frequency diversity gain, and the second processing result is obtained.

[0132] Step C24: Perform despreading processing (such as conjugate symmetric despreading processing) and time-frequency inverse transformation (such as inverse generalized discrete Fourier transform) on the second processing result to obtain a third processing result;

[0133] Step C25: Add a correction term to the third processing result to obtain a fourth processing result; wherein, the fourth processing result is the estimated value of the time-domain symbol that conforms to the Turbo principle;

[0134] The above-mentioned time-domain symbols include offset quadrature amplitude modulation symbols, quadrature amplitude modulation symbols, etc.

[0135] The Turbo principle is a general principle in decoding and signal detection theory, which requires that only extrinsic information is passed between nodes during the iterative processing. Specifically, in the process of estimating time-domain symbols, it means that the estimated value of each symbol should be independent of the prior information of the symbol itself. For example, when estimating the i-th symbol, the prior information of the i-th symbol itself cannot be used (depended on), and the prior information here is the mean and variance converted based on the log-likelihood ratio.

[0136] Step C26: Calculate the first extrinsic information according to the fourth processing result.

[0137] Wherein, in this embodiment, the method for calculating the first extrinsic information can be selected according to the implementation manner of SC-FDMA. Specifically, if SC-FDMA is implemented based on CP-OQAM-OFDM, the fourth processing result can be first converted into an estimated value of quadrature amplitude modulation symbols, and then the first extrinsic information can be calculated using the estimated value of the quadrature amplitude modulation symbols; if SC-FDMA is implemented based on DFT-s-OFDM, the operation of converting into an estimated value of quadrature amplitude modulation symbols can be not performed, but the first extrinsic information can be directly calculated based on the fourth processing result.

[0138] Step C3: First extrinsic information After being subjected to operations such as descrambling, deinterleaving, and rate matching (denoted by ), it is obtained as , and is input to a soft input soft output channel decoder. The channel decoder performs channel decoding and outputs the decoding results of each user and the second extrinsic information .

[0139] As a feasible implementation manner, in this embodiment, the first extrinsic information can be subjected to descrambling operation, deinterleaving operation, and rate matching operation to obtain a fifth processing result; the fifth processing result is input to the soft input soft output channel decoder to obtain decoding results and extrinsic information.

[0140] Step C4: Determine whether the decoding results of each user output by the soft input soft output decoder are correct or whether the maximum number of iterations is reached. If so, directly output the decoding results of each user; if not, proceed to Step C5.

[0141] Step C5: The extrinsic information output by the decoder is obtained as after being subjected to operations such as rate matching, interleaving, and scrambling, and is fed back to the soft input soft output equalizer as prior information, and then returns to Step C2 for the next iteration process, so that the SISO equalizer can obtain a prior estimate of the interference symbols based on the prior information provided by the channel decoder and achieve interference cancellation between symbols and between users.

[0142] Please refer to Figure 7 , Figure 7 which is a processing flow chart of a soft input soft output channel equalizer provided by an embodiment of the present application. The process is as follows: The estimated values of the equivalent frequency domain channel coefficients and the noise power , the frequency domain received signal , and the conversion result of the prior information are subjected to frequency domain equalization processing to obtain an estimated value of the frequency domain signal after spectrum spreading processing (i.e., the first processing result). The conversion result of the prior information includes the vector of the mean value, the mean value , and the variance .

[0143] The estimated value is subjected to frequency domain combined estimation to obtain a combined estimated value of the frequency domain signal (i.e., the second processing result). The combined estimated value is subjected to despreading to obtain an estimated value of the frequency domain signal , perform inverse time-frequency transformation on the estimated value to obtain the time-domain symbol of the estimated value (i.e., the third processing result). Perform Turbo principle correction on the estimated value to obtain the estimated value of the time-domain symbol that satisfies the Turbo principle (i.e., the fourth processing result). Perform extrinsic information calculation on the estimated value to obtain the extrinsic information (i.e., the first extrinsic information), and output the extrinsic information.

[0144] The input of the SISO equalizer includes: the frequency-domain received signal, the estimated value of the equivalent frequency-domain channel coefficient and the noise power , and the prior information . The processing flow of the SISO equalizer can be summarized as the following steps:

[0145] Step D1: Prior information transformation. Different methods are adopted for the prior information transformation for different SC-FDMA implementation methods.

[0146] When SC-FDMA is implemented based on CP-OQAM-OFDM, the method of the prior information transformation is:

[0147] First, transform the input prior information into the statistical information of the complex signal.

[0148] Based on , it can be obtained that has the probability distribution:

[0149] ;

[0150] where . represents the th bit in the signal after operations such as rate matching, interleaving, and scrambling. Then the QAM symbol obtained by QAM modulation has the probability distribution:

[0151] ;

[0152] where represents the th complex symbol in the -order QAM symbol set ; The q-th mapped bit. In this embodiment, statistical information about each QAM symbol, i.e., the mean and variance .

[0153] ;

[0154] ;

[0155] ;

[0156] In the above formula, represents taking the expectation, represents the -th QAM symbol of the u-th user variance.

[0157] Based on the mapping relationship between the OQAM symbol and the QAM symbol , the relationship between their means and variances can be obtained:

[0158] ;

[0159] ;

[0160] Among them, , . The OQAM symbol within the -th OFDM symbol is , then its corresponding mean and variance can be represented by and , that is , .

[0161] The vector form of the mean can be expressed as:

[0162] ;

[0163] Then the mean of the frequency-domain signal can be expressed as: ;

[0164] Performing conjugate symmetric extension on can obtain , then performing conjugate symmetric extension on can obtain the mean of the signal .

[0165] When SC-FDMA is implemented based on DFT-s-OFDM, the method for transforming the prior information is as follows:

[0166] First, the input prior information is transformed into statistical information of complex signals.

[0167] Based on , the probability distribution of can be obtained as:

[0168] ;

[0169] where . denotes the -th bit in the signal after operations such as rate matching, interleaving, and scrambling. The QAM symbol obtained by QAM modulation of

[0170] has a probability distribution of:

[0171] where denotes the -th complex symbol in the set of QAM symbols of order ; denotes the -th mapped bit of the QAM symbol This embodiment can obtain the statistical information about each QAM symbol, that is, the mean and the variance

[0172] ;

[0173] ;

[0174] ;

[0175] In the above formula, denotes taking the expectation, denotes the variance of the -th QAM symbol of the

[0176] -th user. The QAM symbol within the -th OFDM symbol is and Its corresponding mean and variance can be represented by

[0177] ;

[0178] 。

[0179] The mean value in vector form can be expressed as:

[0180] ;

[0181] Then the mean value of the frequency-domain signal can be expressed as: ; For performing symmetric extension can obtain , then for performing symmetric extension can obtain the mean value of the signal 。

[0182] Since and only differ in that the frequency-domain signal is composed of subcarriers and the frequency-domain signal is composed of users, and essentially represent the same signal, so the corresponding mapping process can also be performed based on to obtain the mean value 。

[0183] Step D2: Frequency-domain equalization:

[0184] Based on the estimation of the input frequency-domain received signal, channel, and noise power, and the statistical information obtained in step D1, this step can perform frequency-domain equalization processing to obtain the estimated value of the frequency-domain signal after spectrum expansion processing, that is 。

[0185] Let and respectively represent the estimated values of the input equivalent channel coefficient and the noise power . Then the estimation method of the frequency-domain signal is:

[0186] ;

[0187] where ;

[0188] ;

[0189] denotes the conjugate transpose operation.

[0190] represents the th user at the within one OFDM symbol For different SC - FDMA implementation methods, there are corresponding calculation formulas for the mean of variance.

[0191] If SC - FDMA is implemented based on CP - OQAM - OFDM, the calculation formula is:

[0192] ;

[0193] If SC - FDMA is implemented based on DFT - s - OFDM, the calculation formula is:

[0194] ;

[0195] Since and only differ in the vector composition method and essentially represent the same signal, that is, both represent the frequency - domain signal obtained after spectrum spreading processing. Then the estimated values on each sub - carrier can also be re - organized and arranged to obtain:

[0196] , that is, the estimated value of the frequency - domain signal . represents the mean of the variance of the frequency - domain signal.

[0197] Step D3: Frequency - domain combined estimation.

[0198] Due to the adoption of spectrum spreading processing, in order to obtain frequency - diversity gain, combined estimation processing is performed on in the frequency domain to obtain the combined estimated value of the frequency - domain signal . For different SC - FDMA implementation methods, the calculation formulas for the combined estimated value are respectively:

[0199] When SC - FDMA is implemented based on CP - OQAM - OFDM, the combined estimated value can be expressed as:

[0200] ;

[0201] When SC - FDMA is implemented based on DFT - s - OFDM, the combined estimated value can be expressed as:

[0202] ;

[0203] Among them, . represents the sub - carrier number for combining with the estimated signal on the k - th sub - carrier. For different SC - FDMA implementation methods, It has its corresponding calculation formula.

[0204] If SC-FDMA is implemented based on CP-OQAM-OFDM, the calculation formula is:

[0205] ;

[0206] If SC-FDMA is implemented based on DFT-s-OFDM, the calculation formula is:

[0207] ;

[0208] The subcarrier sequence number k here and both refer to the sequence number within the subcarriers actually occupied by the th user.

[0209] represents the weighting coefficient of the frequency-domain estimated signal on the k-th subcarrier of the th user in the combined estimation process, which is determined by the signal-to-noise ratios on the k-th and and subcarriers:

[0210] ;

[0211] represents the signal-to-noise ratio of the frequency-domain estimated signal on the k-th subcarrier of the th user, and can be expressed as:

[0212] ;

[0213] Among them, represents the true sequence number of the k-th subcarrier of the th user in the subcarriers of the system, satisfying . represents the user sequence number corresponding to the th user on the th subcarrier, satisfying .

[0214] Step D4: Despreading.

[0215] Based on the result after frequency-domain combined estimation, perform despreading processing on it to obtain the estimated value of the frequency-domain signal . The despreading processing adopts different methods for different SC-FDMA implementation methods.

[0216] If SC-FDMA is implemented based on CP-OQAM-OFDM, the calculation formula is:

[0217] ;

[0218] If SC-FDMA is implemented based on DFT-s-OFDM, the calculation formula is:

[0219] ;

[0220] Step D5: Time-frequency inverse transformation.

[0221] Based on the estimated value , the time-domain symbol 's estimated value can be obtained through time-frequency inverse transformation. The time-frequency inverse transformation adopts different methods for different SC-FDMA implementation methods.

[0222] If SC-FDMA is implemented based on CP-OQAM-OFDM, the time-frequency inverse transformation adopts the inverse generalized discrete Fourier transform (IGDFT), and the calculation formula is:

[0223] ;

[0224] If SC-FDMA is implemented based on DFT-s-OFDM, the time-frequency inverse transformation adopts the inverse discrete Fourier transform (IDFT), and the calculation formula is:

[0225] ;

[0226] Step 6: Turbo principle correction: To meet the Turbo principle, this embodiment can add a correction term on the basis of to obtain the time-domain symbol estimation that meets the Turbo principle:

[0227] ;

[0228] Among them, the calculation formula of is different for different SC-FDMA implementation methods:

[0229] If SC-FDMA is implemented based on CP-OQAM-OFDM, the calculation formula is:

[0230] ;

[0231] If SC-FDMA is implemented based on DFT-s-OFDM, the calculation formula is:

[0232] ;

[0233] represents the th diagonal element of the matrix;

[0234] where .

[0235] Step D7: Calculate the extrinsic information.

[0236] For different SC-FDMA implementation methods, the method of obtaining the QAM symbol estimation value for calculating the extrinsic information is also different.

[0237] If SC-FDMA is implemented based on CP-OQAM-OFDM, then based on the relationship between OQAM symbols and QAM symbols, it can also be converted into an estimation of the QAM symbol . Let represent the estimation of the QAM symbol , then there is ;

[0238] If SC-FDMA is implemented based on DFT-s-OFDM, itself is the estimation value of the QAM symbol. Let represent the estimation of the QAM symbol , then there is ;

[0239] represents the OFDM symbol where the th QAM symbol is located, , represents rounding down, represents taking 's remainder, represents the rd element in the vector

[0240] The extrinsic information output by the SISO equalizer can be expressed as:

[0241] ;

[0242] ;

[0243] ;

[0244] ;

[0245] If SC-FDMA is implemented based on CP-OQAM-OFDM, then The calculation formula of

[0246] ;

[0247] If SC-FDMA is implemented based on DFT-s-OFDM, then The calculation formula of

[0248] ;

[0249] ;

[0250] In the above formula, represents the i-th bit value among the corresponding bits of the QAM symbol and represent the variables used in the calculation process.

[0251] is a subset of, representing the set of all QAM symbols where the q-th mapped bit is b.

[0252] The solution of this embodiment combines the MU-MIMO system of FDSS-SE and SC-FDMA single-carrier technologies, provides the Turbo receiving technology with uplink transmission combined with frequency-domain combining, provides extrinsic information feedback to the SISO equalizer through the channel decoder, converts the prior information brought by the error correction of the channel decoder into the prior information of the interference symbols, and enables the equalizer to eliminate interference during the iteration process to obtain the Turbo iteration gain. This embodiment can make full use of the signals on the extended frequency band, improve the received signal-to-noise ratio, and designs the corresponding Turbo receiving processing method in the SC-FDMA single-carrier MU-MIMO scenario, which can effectively suppress the inter-symbol interference and the inter-user interference.

[0253] In an SC-FDMA-based MU-MIMO system, there is interference between the symbols of a user itself, and there is also interference between the symbols of different users. Moreover, these transmitted symbols are the target values to be estimated by the receiver. At the first iteration, the equalizer has no prior information about these symbols. After the first equalization process, a preliminary estimated value of these symbols is obtained, and channel decoding is performed based on the preliminary estimated value. The channel decoder has error correction capabilities. Therefore, feeding back the second extrinsic information output by the channel decoder to the equalizer as prior information can convert the gain brought by the error correction of the channel decoder into a more accurate prior estimate of the transmitted signal by the equalizer. Then, in the subsequent iterative equalization process, it means that there is a more accurate prior estimate of the interference sources (the symbols to be estimated are interference sources with each other), rather than having no prior information at all as in the first iteration. Then the influence of interference can be eliminated during equalization.

[0254] In addition, in order to enable the equalizer to estimate the transmitted symbols more accurately, considering that the spectrum spreading technology is used, some signals in the frequency-domain signal are transmitted twice. This application proposes to perform merging processing on the extended frequency-domain signal during the equalization process, that is, to achieve a more accurate estimate of the frequency-domain signal that has undergone spectrum spreading.

[0255] Therefore, this application utilizes the error correction capability of the channel decoder to provide more accurate prior information about the interfering symbols to the equalizer, thereby helping to reduce the influence of interference sources on the estimation accuracy of each transmitted signal during the equalization process; and for the application of the FDSS-SE technology, the equalizer performs merging estimation to enable the equalizer to complete symbol estimation more accurately; based on the more accurate estimation of the equalizer, it can also provide better first extrinsic information to the channel decoder to help the channel decoder better complete error correction decoding. Through such iteration, the final decoding accuracy is continuously improved.

[0256] In Figure 9 and Figure 10 show the block error rate (BLER) of the Turbo receiver in this embodiment obtained from computer simulation experiments under different modulation and coding schemes (MCS). The abscissa (in dB) represents the noise level. The larger the abscissa value, the smaller the noise. In the computer simulation experiment, SC-FDMA is based on CP-OQAM-OFDM. Operations such as CRC attachment, LDPC channel coding, rate matching, and scrambling during the generation of the transmitted signal are all implemented according to the specifications in the 5G NR protocol. The channel used in the simulation is the CDL-D channel (a channel scenario with a direct path), and it is assumed that the channel estimation used by the receiver is an error-free ideal channel estimation. In the simulation experiment, the roll-off factor of FDSS-SE for each user is set to 1, and the angular distribution relationship of multiple users is that the angular interval between users is 15°. Other parameter settings are shown in Table 1:

[0257] Table 1 Parameter Setting Table

[0258]

[0259] Figure 9 and Figure 10 respectively show the BLER performance of the Turbo receiver in this embodiment when the MCS is 2 (modulation method is QPSK, code rate is 308 / 1024) and 7 (modulation method is 16QAM, code rate is 490 / 1024).

[0260] From Figure 9 and Figure 10 it can be seen that, compared with the "traditional Turbo receiver without considering combining", the performance of the "Turbo receiver of the present invention" is significantly improved. Whether it is in the case of 1 iteration or 2 iterations, a lower BLER is achieved under the same noise power. Under the same number of iterations, the BLER performance gain of the "Turbo receiver of the present invention" comes from the frequency diversity gain brought by the frequency domain combining process. The improvement in the BLER performance of the "Turbo receiver of the present invention" when iterating 2 times compared with iterating 1 time comes from the iterative gain brought by the Turbo iterative process to eliminate inter-symbol and inter-user interference.

[0261] A signal processing system for a receiver provided by an embodiment of the present application includes:

[0262] A receiving module, configured to determine the frequency domain received signal of the base station;

[0263] A priori information setting module, configured to initialize the a priori information;

[0264] An equalization processing module, configured to perform soft input soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power, and the a priori information to obtain a first extrinsic information;

[0265] A decoding module, configured to process the first extrinsic information by using a soft input soft output channel decoder to obtain a decoding result and a second extrinsic information;

[0266] A judgment module, configured to judge whether the decoding result generated most recently is correct; if so, output the decoding result generated most recently; if not, update the a priori information according to the second extrinsic information generated most recently, and enter the step of performing soft input soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power, and the a priori information.

[0267] In this embodiment, the prior information is initialized before the first iteration. Soft input soft output equalization processing is performed according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power, and the prior information to obtain the first extrinsic information. The soft input soft output channel decoder is used to process the first extrinsic information to obtain the decoding result and the second extrinsic information. If the decoding result is correct, it is output. If the decoding result is incorrect, the prior information is updated according to the second extrinsic information generated most recently, and the soft input soft output equalization processing is iteratively performed. The above solution continuously updates the prior information and the extrinsic information during the iteration process, thereby effectively reducing the impact of interference and improving the communication quality of the system. Therefore, this embodiment can suppress inter-symbol interference and inter-user interference in a multi-user multiple-input multiple-output system.

[0268] Further, the process by which the equalization processing module performs soft input soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power, and the prior information to obtain the first extrinsic information includes: determining the estimated value of the equivalent frequency domain channel coefficient and the estimated value of the noise power; using the soft input soft output equalizer to process the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power, and the prior information to obtain the first extrinsic information.

[0269] Among them, the process by which the equalization processing module generates the first extrinsic information includes:

[0270] Converting the prior information into statistical information of complex signals;

[0271] Performing frequency domain equalization processing according to the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power, and the statistical information to obtain a first processing result; where the first processing result is the estimated value of the frequency domain signal after spectrum spreading processing;

[0272] Performing combined estimation processing on the first processing result in the frequency domain to obtain a second processing result; where the second processing result is the combined estimated value of the frequency domain signal;

[0273] Performing de-spectrum spreading processing and time-frequency inverse transformation on the second processing result to obtain a third processing result;

[0274] Adding a correction term to the third processing result to obtain a fourth processing result; where the fourth processing result is the time domain symbol estimated value that conforms to the Turbo principle;

[0275] Calculating the first extrinsic information according to the fourth processing result.

[0276] Further, the process by which the equalization processing module performs combined estimation processing on the first processing result in the frequency domain to obtain the second processing result includes:

[0277] Determine the signal-to-noise ratio of each subcarrier in the first processing result, and calculate the weighting coefficient of each subcarrier using the signal-to-noise ratio;

[0278] Perform a frequency-domain combining estimation operation on the first processing result using the weighting coefficient to obtain the second processing result.

[0279] Furthermore, the equalization processing module calculates the first extrinsic information according to the fourth processing result.

[0280] Furthermore, the process of initializing the prior information by the prior information setting module includes: before the first iteration, taking the log-likelihood ratio of the bit sequence of the transmitted signal of each user equal to 0 as the prior information.

[0281] Furthermore, the process of the decoding module processing the first extrinsic information using a soft-input soft-output channel decoder includes: performing a descrambling operation, a deinterleaving operation, and a de-rate matching operation on the first extrinsic information to obtain a fifth processing result; inputting the fifth processing result into the soft-input soft-output channel decoder.

[0282] Furthermore, it further includes:

[0283] An iteration count recording module, configured to update the iteration count after updating the prior information according to the second extrinsic information generated most recently; and further configured to determine whether the iteration count is greater than a preset value before determining whether the decoding result generated most recently is correct; if so, output the decoding result generated most recently.

[0284] Furthermore, the process of the determination module updating the prior information according to the second extrinsic information generated most recently includes: performing a rate matching operation, an interleaving operation, and a scrambling operation on the second extrinsic information to obtain a sixth processing result; updating the prior information to the sixth processing result.

[0285] Since the embodiments in the system part correspond to the embodiments in the method part, for the embodiments in the system part, please refer to the description of the embodiments in the method part, and will not be elaborated here.

[0286] This application also provides a storage medium, on which a computer program is stored, and when the computer program is executed, the steps provided in the above embodiments can be implemented. The storage medium may include: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc that can store program codes.

[0287] The present application further provides an electronic device, which may include a memory and a processor. A computer program is stored in the memory. When the processor calls the computer program in the memory, the steps provided in the above embodiments can be implemented. Of course, the electronic device may further include various network interfaces, power supplies and other components.

[0288] The present application further provides a computer program product, including a computer program and / or computer instructions. When the computer program / instructions are executed by a processor, the steps of the signal processing method of the above receiver are implemented.

[0289] Please refer to Figure 8 , Figure 8 which is a schematic diagram of the implementation principle of a computer program product provided by an embodiment of the present application. The computer program product includes a signal initialization program, an equalization processing program, a decoding program and a decision program.

[0290] The operations implemented when the signal initialization program is executed by the processor are: determining the frequency-domain received signal of the base station and initializing the prior information;

[0291] The operations implemented when the equalization processing program is executed by the processor are: performing soft input soft output equalization processing according to the frequency-domain received signal, the equivalent frequency-domain channel coefficient, the noise power and the prior information to obtain a first extrinsic information;

[0292] The operations implemented when the decoding program is executed by the processor are: processing the first extrinsic information by using a soft input soft output channel decoder to obtain a decoding result and a second extrinsic information;

[0293] The operations implemented when the decision program is executed by the processor are: determining whether the most recently generated decoding result is correct; if so, outputting the most recently generated decoding result; if not, updating the prior information according to the most recently generated second extrinsic information and entering the step of performing soft input soft output equalization processing according to the frequency-domain received signal, the equivalent frequency-domain channel coefficient, the noise power and the prior information.

[0294] The embodiments in the specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple. For the relevant parts, refer to the description in the method part. It should be noted that for those of ordinary skill in the art in the technical field of the present application, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the present application.

[0295] It should also be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

Claims

1. A signal processing method for a receiver, characterized in that: include: Determine the frequency domain received signal of the base station and initialize the prior information; Perform soft-input and soft-output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain first external information; Processing the first external information by using a soft-input and soft-output channel decoder to obtain a decoding result and a second external information; Determine whether the most recently generated decoding result is correct; If so, output the most recently generated decoding result; If not, the prior information is updated according to the second external information generated most recently, and the step of performing soft input and soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information is entered.

2. The signal processing method of the receiver according to claim 1, characterized in that: Performing soft input and soft output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain first external information includes: Determining an estimated value of the equivalent frequency domain channel coefficient and an estimated value of the noise power; Processing the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power and the prior information using a soft-input soft-output equalizer to obtain the first external information; The process of the soft-input soft-output equalizer generating the first external information includes: Converting the prior information into statistical information of a complex signal; Performing frequency domain equalization processing according to the frequency domain received signal, the estimated value of the equivalent frequency domain channel coefficient, the estimated value of the noise power and the statistical information to obtain a first processing result; wherein the first processing result is an estimated value of the frequency domain signal after spectrum expansion processing; Performing a combined estimation process on the first processing result in the frequency domain to obtain a second processing result; wherein the second processing result is a combined estimation value of the frequency domain signal; Performing spectrum despreading processing and inverse time-frequency transform on the second processing result to obtain a third processing result; adding a correction term to the third processing result to obtain a fourth processing result; The first external information is calculated according to the fourth processing result.

3. The signal processing method of the receiver according to claim 2, characterized in that: Performing a combined estimation process on the first processing result in the frequency domain to obtain a second processing result, including: Determine a signal-to-noise ratio of each subcarrier in the first processing result, and calculate a weighting coefficient of each subcarrier using the signal-to-noise ratio; The first processing result is subjected to a frequency domain merging estimation operation using the weighting coefficient to obtain the second processing result.

4. The signal processing method of the receiver according to claim 2, characterized in that: Calculating the first external information according to the fourth processing result includes: Converting the fourth processing result into a quadrature amplitude modulation symbol estimation value; The first extrinsic information is calculated using the quadrature amplitude modulation symbol estimation value.

5. The signal processing method of the receiver according to claim 1, characterized in that: Processing the first external information using a soft-input soft-output channel decoder includes: performing a descrambling operation, a deinterleaving operation, and a derate matching operation on the first external information to obtain a fifth processing result; The fifth processing result is input to the soft-input soft-output channel decoder.

6. The signal processing method of the receiver according to claim 1, characterized in that: After updating the prior information according to the second external information generated most recently, the method further includes: Update the number of iterations; Accordingly, before judging whether the most recently generated decoding result is correct, the following steps are also included: Determine whether the number of iterations is greater than a preset value; If so, the most recently generated decoding result is output.

7. The signal processing method of the receiver according to claim 1, characterized in that: Updating the prior information according to the second external information generated most recently includes: performing a rate matching operation, an interleaving operation, and a scrambling operation on the second external information to obtain a sixth processing result; The priori information is updated to the sixth processing result.

8. A signal processing system for a receiver, characterized in that: include: A receiving module, used to determine a frequency domain received signal of a base station; A priori information setting module, used to initialize the priori information; An equalization processing module, used for performing soft-input and soft-output equalization processing according to the frequency domain received signal, the equivalent frequency domain channel coefficient, the noise power and the prior information to obtain first external information; A decoding module, used for processing the first external information by using a soft-input and soft-output channel decoder to obtain a decoding result and a second external information; A judgment module is used to judge whether the decoding result generated most recently is correct; if so, output the decoding result generated most recently; if not, update the prior information according to the second external information generated most recently, and enter the step of performing soft input and soft output equalization processing according to the frequency domain received signal, equivalent frequency domain channel coefficient, noise power and the prior information.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the signal processing method of the receiver according to any one of claims 1 to 7 when calling the computer program in the memory.

10. A storage medium, characterized in that: The storage medium stores computer executable instructions, and when the computer executable instructions are loaded and executed by the processor, the steps of the signal processing method of the receiver according to any one of claims 1 to 7 are implemented.

11. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the signal processing method of the receiver according to any one of claims 1 to 7 are implemented.

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