CN114363135A - OTFS signal processing method and device - Google Patents
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Abstract
The invention discloses an OTFS signal processing method and a device, wherein the method comprises the following steps: carrying out interleaving operation on a plurality of groups of time domain data obtained after inverse Fourier transform at a sending end; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix; de-interleaving the received signal at the receiving end, and obtaining an original signal sent by the sending end based on data obtained by de-interleaving; wherein the deinterleaving operation is a reverse operation of the interleaving operation. The OTFS signal processing scheme of the invention can keep the good sparse characteristic of the channel matrix, is convenient for QRD demodulation and reduces the complexity.
Description
Technical Field
The present invention relates to the field of wireless communication technologies, and in particular, to an OTFS signal processing method and apparatus.
Background
The transmission channel of a wireless signal has a multipath effect, that is, after the signal is sent from a sending end, for example, the signal is sent by a base station, and before the signal reaches a receiving end, for example, a mobile phone, the middle of the signal may experience multiple transmission paths, for example, multiple reflection or direct paths exist between the base station BS and user equipment/terminal UE at the same time, so that the signal reaching the UE end is a superposition of the multiple paths. Each path may correspond to a different delay and phase, and attenuation. The superposition of delays, phases and attenuations of the different paths forms the radio link between the whole transmission and the whole reception. Multipath effects are manifested in the frequency domain as frequency selective fading. That is, when signals are transmitted at different frequencies, the phases arriving at the receiving end are different due to different corresponding wavelengths, so that the signals are coherently cancelled.
When the receiving end device moves, because the incident angles of the signals of the multiple paths reaching the receiving end are different, different paths have different doppler frequency offsets, especially when the UE moves faster. In this case, the presence of frequency offset significantly affects the demodulation of the signal, which may lead to disadvantages such as an increase in error rate, a decrease in channel capacity, and an increase in interference.
For multipath effect, in a conventional OFDM (Orthogonal Frequency Division Multiplexing) processing manner, a channel with a wide bandwidth is decomposed into a plurality of parallel narrowband channels (subcarriers), so that the interior of each narrowband channel is approximately flat (that is, no fading exists in each subcarrier), a signal to be transmitted is modulated onto each subcarrier, and the signal is converted into a Frequency domain by using IFFT (Inverse Fast Fourier Transform) to be transmitted. OFDM waveforms are characterized by being sensitive to frequency offset. Because a plurality of frequency domain subcarriers of the OFDM are orthogonal to each other, when there is frequency offset, the orthogonal characteristic between the subcarriers is destroyed, so that mutual interference occurs between the subcarriers, and the system performance is reduced. Therefore, the OFDM system is usually used in an occasion where the UE moving speed is low or an occasion where the high speed doppler effect is strong, a complex frequency offset estimation compensation process is required, which not only increases the system complexity, but also reduces the performance.
In contrast, an OTFS (Orthogonal Time Frequency Space) waveform modulates a signal to a delay-doppler domain first, and then transforms the signal from the delay-doppler domain to a Time-Frequency domain by using an ISFFT (Inverse systematic Finite Fourier Transform) Transform, and then transmits the signal by using an OFDM system. The OTFS transmission process may be considered as a process in which preprocessing is added on the basis of OFDM, that is, an ISFFT transformation is added. Accordingly, at the receiving end, the time-frequency domain data after the OFDM processing is transformed into the time delay-doppler domain by SFFT (symmetric Fourier transform) for subsequent demodulation. For the OTFS system, as the modulation signal is equivalent to be placed on a delay-Doppler domain, the receiving and sending of the modulation signal are not influenced by multipath Doppler, so that the system adopting the OTFS can obtain better system performance in a high-speed scene.
The modulation and transformation, including IFFT, FFT, ISFFT, SFFT, etc., are all performed in the digital domain, i.e., on the corresponding digital processor, and the transmission and transmission of signals are performed in the analog domain, i.e., transmitted through the corresponding rf device.
For a Multiple Input Multiple Output (MIMO) system, the mathematical model of the OFDM system can be equivalent to:
y＝Hx+n (1)
wherein H is Nt×NrIs determined by the radio channel between transceiving, wherein each element represents the channel gain between the corresponding antennas. x represents NtX 1, y represents NrX 1 received signal. And a signal detection process at the receiving end, namely recovering the transmitted signal x from the received y.
The main purpose of detection is to recover the signal x from the received y. Different detection methods have different complexities. One common detection method, QRD (QR decomposition) detection, is to perform QR decomposition on a channel matrix H, that is:
H＝QR
wherein Q represents an orthogonal matrix, R represents an upper triangular matrix, and common decomposition methods comprise Gram-Schmidt orthogonalization, givens transformation, Householder transformation and the like. Since Q is an orthogonal matrix, Q is-1＝QHThen, equation 1 can be rewritten as:
QHy＝Rx+QHn
since R is an upper triangular matrix, all elements of x can be computed one by one starting from the last element of x. The method is based on QR decomposition detection.
Similar to OFDM, the modulation and demodulation of OTFS can be considered as adding two preprocessing modules at the transceiving end respectively on top of OFDM system, as shown in fig. 1.
The ISFFT of the sending end converts the signal after constellation mapping from a time delay-Doppler domain to a time-frequency domain, and sends the signal by using an OFDM modulation-demodulation system. The SFFT of the receiving end converts the time-frequency domain data output by the OFDM into a delay Doppler domain to obtain the information obtained by the transmitting end.
Mathematically, in the delay-doppler domain, the information of the transceiving end can be expressed as:
y＝Hx+n (2)
equation 2 is consistent with the form of equation 1. But since the preprocessing and post-processing modules are added in equation 2, the form of the channel matrix, i.e., H, is different from that in equation 1. Specifically, H in equation 2 can be expressed as:
wherein, FNRepresenting an N-dimensional DFT matrix, IMRepresents an M-dimensional identity matrix and a matrix,
represents the Kronecker product, hiThe gain of the ith propagation path is shown, T is a permutation matrix of M × N dimensions, i.e., the last row of the unit matrix of M × N is cyclically shifted to the first row, taking a matrix of 3 × 3 as an example:
delta represents an M multiplied by N diagonal matrix with major diagonal elements in order
liAnd viRespectively, the delay and doppler of the ith propagation path.
The mathematical form of H expressed in formula 3 makes the final H matrix an M × N dimensional matrix, and the QRD detection method is used to make the QR decomposition complexity of the large dimensional matrix higher, making it difficult to use the QRD method well. Therefore, it is necessary to develop a new OTFS signal processing method.
Disclosure of Invention
The invention provides an OTFS signal processing method and device, and aims to solve the technical problem that a QRD method is difficult to well utilize in an existing OTFS waveform system.
In order to solve the technical problems, the invention provides the following technical scheme:
the Fourier transform/inverse Fourier transform described in the invention can be Discrete Fourier Transform (DFT)/Inverse Discrete Fourier Transform (IDFT), and can also be Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT), and the description can be mutually equivalent and replaced.
On one hand, the invention provides an OTFS signal processing method, which is suitable for an OTFS (Orthogonal Time Frequency Space) waveform system detected by a receiving end by using a QRD (QR decomposition), and the OTFS signal processing method includes:
carrying out inverse Fourier transform on a plurality of groups of frequency domain data at a sending end to obtain a plurality of groups of time domain data, and carrying out interleaving operation on the plurality of groups of time domain data; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix;
de-interleaving the received signal at the receiving end, and acquiring an original signal sent by the sending end based on data obtained by de-interleaving; wherein the deinterleaving operation is a reverse operation of the interleaving operation.
Further, at the sending end, the obtaining process of the two-dimensional matrix is as follows:
placing the data symbols after constellation mapping on an M multiplied by N time delay-Doppler two-dimensional resource grid; wherein M represents a delay dimension and N represents a Doppler dimension;
performing ISFFT (Inverse Symplectic Finite Fourier Transform) on the data symbols on the delay-Doppler two-dimensional resource grid to Transform the data symbols into a time-frequency domain to obtain M × N two-dimensional time-frequency domain data; the frequency domain dimension is M, and the time domain dimension is N;
for the obtained M × N two-dimensional time-frequency domain data, performing IFFT (Inverse Fast Fourier Transform) on the M frequency domain data of each column to obtain M data points, and combining the obtained N sets of results into an M × N time-domain two-dimensional matrix, where each column of the time-domain two-dimensional matrix is obtained by IFFT of each column of the corresponding two-dimensional time-frequency domain data;
or
Placing the data symbols after constellation mapping on an M multiplied by N time delay-Doppler two-dimensional resource grid; wherein M represents a delay dimension and N represents a Doppler dimension;
performing ISFFT (Inverse Symplectic Finite Fourier Transform) on the data symbols on the delay-Doppler two-dimensional resource grid to Transform the data symbols into a time-frequency domain to obtain N multiplied by M two-dimensional time-frequency domain data; the frequency domain dimension is M, and the time domain dimension is N;
the method includes the steps that N × M two-dimensional time-frequency domain data are subjected to Inverse Fast Fourier Transform (IFFT) on M frequency domain data of each row to obtain M data points, and N groups of obtained results are combined into an N × M time-domain two-dimensional matrix, wherein each row of the time-domain two-dimensional matrix is obtained by IFFT of each column of the corresponding two-dimensional time-frequency domain data.
Further, when combining the obtained N sets of results into an M × N two-dimensional time domain matrix, the interleaving operation is:
transposing the M × N two-dimensional time domain matrix into an N × M two-dimensional matrix,
extracting data by columns from the N multiplied by M two-dimensional matrix obtained after the inversion;
or extracting data from the M multiplied by N two-dimensional matrix according to rows; when combining the obtained N sets of results into an N × M two-dimensional time domain matrix, the interleaving operation is:
transposing the NxM two-dimensional time domain matrix into an MxN two-dimensional matrix,
extracting data according to rows from an M multiplied by N two-dimensional matrix obtained after the inversion;
or, extracting data from the N × M two-dimensional matrix in columns;
the data extraction according to rows or columns includes extracting all data of one row/column, and then sequentially extracting data of the next row/column.
Further, the deinterleaving operation is:
for received signals, putting the signals into an N multiplied by M matrix according to columns;
transposing the obtained NxM matrix to obtain an MxN matrix;
or
Putting the received signals into an M multiplied by N matrix according to rows to obtain the M multiplied by N matrix;
after all the data of a full row/column are placed, the data of the next row/column are placed in sequence.
Optionally, before sending, adding P cyclic prefixes to the data extracted according to the rows or columns, and sending the data every M data; the cyclic prefix is the last P of the M data; p is determined by a pre-configured or pre-defined method.
Correspondingly, at the receiving end, before putting M data, the initial P cyclic prefix data are removed and then put in by column or row.
Further, the OTFS signal processing method further includes:
the base station end adopts signaling information to indicate a receiving end through a control channel and starts the interleaving operation; the signaling information includes: whether to turn on, time of interleaving resource blocks, and frequency of interleaving resource blocks.
On the other hand, the present invention further provides an OTFS signal processing apparatus, which is suitable for an OTFS waveform system using QRD detection at a receiving end, and the OTFS signal processing apparatus includes:
the interleaving module is used for performing interleaving operation on a plurality of groups of time domain data obtained after the inverse Fourier transform is performed on a plurality of groups of frequency domain data at the sending end; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix;
the de-interleaving module is used for performing de-interleaving operation on the received signals at the receiving end; the receiving end obtains an original signal sent by the sending end based on data obtained by the de-interleaving operation of the de-interleaving module; the de-interleaving operation is the reverse of the interleaving operation.
In yet another aspect, the present invention also provides an electronic device comprising a processor and a memory; wherein the memory has stored therein at least one instruction that is loaded and executed by the processor to implement the above-described method.
In yet another aspect, the present invention also provides a computer-readable storage medium having at least one instruction stored therein, the instruction being loaded and executed by a processor to implement the above method.
The technical scheme provided by the invention has the beneficial effects that at least:
the OTFS signal processing method provided by the invention adds interleaving and de-interleaving operations in an OTFS waveform system, so that H has a better form, namely H is in a form of a block Hesenberg matrix. The H matrix obtained by the OTFS signal processing method has a good mathematical form, only the secondary diagonal blocks under the main diagonal block are not 0, and the rest are 0, so that the quick operation of QR decomposition is facilitated. The OTFS signal processing method can keep the good sparse characteristic of the channel matrix, is convenient for QRD demodulation and reduces the complexity.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic diagram of a modulation and demodulation process of a conventional OTFS waveform modulation system;
fig. 2 is a schematic diagram of an OTFS system using an OTFS signal processing method provided by an embodiment of the present invention;
fig. 3 is a schematic diagram of an interleaving operation provided by an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First embodiment
The embodiment provides an OTFS signal processing method, which is suitable for an OTFS waveform system with a QRD detection adopted at a receiving end; as shown in fig. 2, in this embodiment, a channel interleaving module is added after the OFDM modulation at the transmitting end, and a corresponding de-interleaving module is added before the OFDM demodulation at the receiving end, so that the channel in the delay-doppler domain has a good mathematical format. The interleaving module and the deinterleaving module are shown in fig. 2 as dashed boxes. Based on this, the OTFS signal processing method includes the following processing procedures:
carrying out inverse Fourier transform on a plurality of groups of frequency domain data at a sending end to obtain a plurality of groups of time domain data, and carrying out interleaving operation on the plurality of groups of time domain data; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix; wherein, the inverse fourier transform may be OFDM (Orthogonal Frequency Division Multiplexing) modulation;
de-interleaving the received signal at the receiving end, and acquiring an original signal sent by the sending end based on data obtained by de-interleaving; wherein the deinterleaving operation is a reverse operation of the interleaving operation.
Specifically, the process of sending and receiving data by the OTFS system using the method of the present embodiment is as follows:
a transmitting end:
1. the data symbols after constellation mapping are placed on an M multiplied by N time delay-Doppler two-dimensional resource grid; wherein M represents a delay dimension and N represents a Doppler dimension;
2. performing ISFFT on the data symbols on the two-dimensional resource grid to convert the data symbols into a time-frequency domain, wherein the obtained data is M multiplied by N two-dimensional time-frequency domain data; wherein M represents a frequency domain dimension and N represents a time domain dimension;
3. for the M multiplied by N two-dimensional time-frequency domain data, for M frequency domain data in each column, performing IFFT to obtain M data points, and combining the obtained N groups of results into an M multiplied by N two-dimensional matrix;
4. interleaving the M × N two-dimensional matrix obtained in the step 3, wherein an interleaving process is shown in fig. 3:
firstly transposing an M multiplied by N matrix into N multiplied by M, then extracting data according to columns and sending.
Here, it should be noted that the matrix generated in step 1-3 may also be represented as N × M (for example, placed by rows), and in this case, the same method is also used, and the matrix is transposed and then decimated by rows.
The data extraction according to the rows or the columns is that after all data of one row/column is extracted, data of the next row/column is sequentially extracted.
Optionally, before sending, adding P cyclic prefixes to the data extracted according to the rows or columns, and sending the data every M data; the cyclic prefix is the last P of the M data; p is determined by a pre-configured or pre-defined method. Accordingly, at the receiving end, before each M data is put in, the initial P cyclic prefix data needs to be removed and then put in by column or row.
It should be noted here that adding a cyclic prefix is an optional function, where P may also be 0, and the specific value of P may be different for different sets of M data.
Receiving end:
1. corresponding to the step 4 in the receiving end, for the received MN × 1 signal, firstly putting the signal into an N × M matrix according to columns, and then transposing the matrix to obtain an M × N matrix;
2. performing FFT transformation on the matrix of M multiplied by N, and transforming the matrix to a time-frequency domain;
3. SFFT transformation is carried out on the data of the time-frequency domain, and the data are transformed to a delay Doppler domain;
4. for the data in the delay-doppler domain, vectors of MN × 1 are extracted, and QRD detection is performed.
Further, the OTFS signal processing method of the present embodiment may further include: the receiving end can be indicated by the signaling information at the base station end, and the interleaving operation is started. The signaling information includes: whether to turn on, time of interleaving resource blocks, and frequency of interleaving resource blocks. For example, the base station indicates through the control channel that the interleaving operation will be started for the nth data frame. After receiving the indication, the terminal device starts de-interleaving on the nth data frame and applies the rapid QRD detection algorithm.
In summary, the embodiment provides an OTFS signal processing method, which can be applied to any OTFS system implemented based on OFDM; the OTFS signal processing method of the embodiment is used in any scene needing high-speed communication, such as high-speed rails, car networking and the like, and the channel matrix can keep good sparse characteristics, so that QRD demodulation is facilitated, complexity is reduced, and the OTFS signal processing method has good application prospects and market value.
Second embodiment
The embodiment provides an OTFS signal processing apparatus, which includes the following modules:
the interleaving module is used for performing interleaving operation on a plurality of groups of time domain data obtained after the inverse Fourier transform is performed on a plurality of groups of frequency domain data at the sending end; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix;
the de-interleaving module is used for performing de-interleaving operation on the received signals at the receiving end; the receiving end obtains an original signal sent by the sending end based on data obtained by the de-interleaving operation of the de-interleaving module; the de-interleaving operation is the reverse of the interleaving operation.
The OTFS signal processing apparatus of the present embodiment corresponds to the OTFS signal processing method of the first embodiment described above; the functions realized by the functional modules in the OTFS signal processing apparatus of the present embodiment correspond to the flow steps in the OTFS signal processing method of the first embodiment one to one; and thus will not be described in detail herein.
Third embodiment
The present embodiment provides an electronic device, which includes a processor and a memory; wherein the memory has stored therein at least one instruction that is loaded and executed by the processor to implement the method of the first embodiment.
The electronic device may generate a large difference due to different configurations or performances, and may include one or more processors (CPUs) and one or more memories, where at least one instruction is stored in the memory, and the instruction is loaded by the processors and executes the method described above
Fourth embodiment
The present embodiment provides a computer-readable storage medium, in which at least one instruction is stored, and the instruction is loaded and executed by a processor to implement the method of the first embodiment. The computer readable storage medium may be, among others, ROM, random access memory, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like. The instructions stored therein may be loaded by a processor in the terminal and perform the above-described method.
Furthermore, it should be noted that the present invention may be provided as a method, apparatus or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media having computer-usable program code embodied in the medium.
Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.
Finally, it should be noted that while the above describes a preferred embodiment of the invention, it will be appreciated by those skilled in the art that, once the basic inventive concepts have been learned, numerous changes and modifications may be made without departing from the principles of the invention, which shall be deemed to be within the scope of the invention. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.
Claims (8)
1. An OTFS signal processing method is applicable to an OTFS (Orthogonal Time Frequency Space) waveform system detected by a receiving end by using a QRD (QR decomposition ), and is characterized by comprising the following steps:
carrying out inverse Fourier transform on a plurality of groups of frequency domain data at a sending end to obtain a plurality of groups of time domain data, and carrying out interleaving operation on the plurality of groups of time domain data; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix;
de-interleaving the received signal at the receiving end, and acquiring an original signal sent by the sending end based on data obtained by de-interleaving; wherein the deinterleaving operation is a reverse operation of the interleaving operation.
2. The OTFS signal processing method according to claim 1, wherein at the sending end, the obtaining process of the two-dimensional matrix is:
placing the data symbols after constellation mapping on an M multiplied by N time delay-Doppler two-dimensional resource grid; wherein M represents a delay dimension and N represents a Doppler dimension;
performing ISFFT (Inverse Symplectic Finite Fourier Transform) on the data symbols on the delay-Doppler two-dimensional resource grid to Transform the data symbols into a time-frequency domain to obtain M × N two-dimensional time-frequency domain data; the frequency domain dimension is M, and the time domain dimension is N;
for the obtained M × N two-dimensional time-frequency domain data, performing IFFT (Inverse Fast Fourier Transform) on the M frequency domain data of each column to obtain M data points, and combining the obtained N sets of results into an M × N time-domain two-dimensional matrix, where each column of the time-domain two-dimensional matrix is obtained by IFFT of each column of the corresponding two-dimensional time-frequency domain data;
or
Placing the data symbols after constellation mapping on an M multiplied by N time delay-Doppler two-dimensional resource grid; wherein M represents a delay dimension and N represents a Doppler dimension;
performing ISFFT (Inverse Symplectic Finite Fourier Transform) on the data symbols on the delay-Doppler two-dimensional resource grid to Transform the data symbols into a time-frequency domain to obtain N multiplied by M two-dimensional time-frequency domain data; the frequency domain dimension is M, and the time domain dimension is N;
for the obtained N × M two-dimensional time-frequency domain data, performing IFFT (Inverse Fast Fourier Transform) on the M frequency domain data of each row to obtain M data points, and combining the obtained N sets of results into an N × M time-domain two-dimensional matrix, where each row of the time-domain two-dimensional matrix is obtained by IFFT in each column of the corresponding two-dimensional time-frequency domain data.
3. The OTFS signal processing method of claim 2, wherein when combining the obtained N sets of results into an M x N two-dimensional time domain matrix, the interleaving operation is:
transposing the M × N two-dimensional time domain matrix into an N × M two-dimensional matrix,
extracting data by columns from the N multiplied by M two-dimensional matrix obtained after the inversion;
or extracting data from the M multiplied by N two-dimensional matrix according to rows;
when combining the obtained N sets of results into an N × M two-dimensional time domain matrix, the interleaving operation is:
transposing the NxM two-dimensional time domain matrix into an MxN two-dimensional matrix,
extracting data according to rows from an M multiplied by N two-dimensional matrix obtained after the inversion;
or, extracting data from the N × M two-dimensional matrix in columns;
the data extraction according to rows or columns includes extracting all data of one row/column, and then sequentially extracting data of the next row/column.
4. The OTFS signal processing method of claim 3, wherein the de-interleaving operation is to:
for received signals, putting the signals into an N multiplied by M matrix according to columns;
transposing the obtained NxM matrix to obtain an MxN matrix;
or
Putting the received signals into an M multiplied by N matrix according to rows to obtain the M multiplied by N matrix;
the row-wise or column-wise placement is to place all data of a full row/column and then place data of the next row/column in sequence.
5. The OTFS signal processing method according to claim 3, wherein before transmission, the data extracted by row or column is transmitted by adding P cyclic prefixes to every M data; the cyclic prefix is the last P of the M data; p is determined by a pre-configured or pre-defined method.
6. The OTFS signal processing method of claim 5, wherein the putting in is performed after removing the first P cyclic prefix data before putting in M data, and then by column or row.
7. The OTFS signal processing method according to any one of claims 1-6, further comprising:
the base station end adopts signaling information to indicate a receiving end through a control channel and starts the interleaving operation; the signaling information includes: whether to turn on, time of interleaving resource blocks, and frequency of interleaving resource blocks.
8. An OTFS signal processing apparatus, which is suitable for an OTFS waveform system using QRD detection at a receiving end, the OTFS signal processing apparatus comprising:
the interleaving module is used for performing interleaving operation on a plurality of groups of time domain data obtained after the inverse Fourier transform is performed on a plurality of groups of frequency domain data at the sending end; wherein the interleaving operation is: combining the multiple groups of time domain data into a two-dimensional matrix according to rows, extracting the two-dimensional matrix according to columns, and sending the two-dimensional matrix; or combining the multiple groups of time domain data into a two-dimensional matrix according to columns, extracting the two-dimensional matrix according to rows, and sending the two-dimensional matrix;
the de-interleaving module is used for performing de-interleaving operation on the received signals at the receiving end; the receiving end obtains an original signal sent by the sending end based on data obtained by the de-interleaving operation of the de-interleaving module; the de-interleaving operation is the reverse of the interleaving operation.
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| CN115174335A (en) * | 2022-07-19 | 2022-10-11 | 西安电子科技大学 | OTFS (optical transport File System) secure transmission method based on interleaving and replacing mechanism |
| CN116389214A (en) * | 2023-06-05 | 2023-07-04 | 四川科冠电子有限公司 | Noise reduction method, noise reduction terminal and medium suitable for voltage power line carrier communication |
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| CN115174335A (en) * | 2022-07-19 | 2022-10-11 | 西安电子科技大学 | OTFS (optical transport File System) secure transmission method based on interleaving and replacing mechanism |
| CN116389214A (en) * | 2023-06-05 | 2023-07-04 | 四川科冠电子有限公司 | Noise reduction method, noise reduction terminal and medium suitable for voltage power line carrier communication |
| CN116389214B (en) * | 2023-06-05 | 2023-08-08 | 四川科冠电子有限公司 | Noise reduction method, noise reduction terminal and medium suitable for voltage power line carrier communication |
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| CN114363135B (en) | 2023-09-15 |
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