WO2016023195A1 - Procédé de transmission de symbole de fréquence pilote, procédé de réception, et émetteur et récepteur - Google Patents

Procédé de transmission de symbole de fréquence pilote, procédé de réception, et émetteur et récepteur Download PDF

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Publication number
WO2016023195A1
WO2016023195A1 PCT/CN2014/084290 CN2014084290W WO2016023195A1 WO 2016023195 A1 WO2016023195 A1 WO 2016023195A1 CN 2014084290 W CN2014084290 W CN 2014084290W WO 2016023195 A1 WO2016023195 A1 WO 2016023195A1
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Prior art keywords
signal
symbol
fbmc
frequency
pilot
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PCT/CN2014/084290
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English (en)
Chinese (zh)
Inventor
屈代明
江涛
崔文佳
陈磊
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华为技术有限公司
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Priority to PCT/CN2014/084290 priority Critical patent/WO2016023195A1/fr
Publication of WO2016023195A1 publication Critical patent/WO2016023195A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems

Definitions

  • the embodiments of the present invention relate to the field of communications technologies, and in particular, to a method for transmitting pilot symbols, a receiving method, a transmitter, and a receiver. Background technique
  • the filter bank multi-carrier (English full name Filter BanK Multi-Carrier, English abbreviation FBMC) signal is a multi-carrier modulation technology, compared to Orthogonal Frequency Division Multiplexing (English full name Orthogonal Frequency Division Multiplexing, English OFDM for short), FBMC has Lower out-of-band radiation and higher spectral efficiency have good application prospects.
  • An important feature of FBMC is that there are different degrees of mutual interference between adjacent subcarriers and adjacent FBMC symbols. For example, the transmitted symbols on any one time-frequency resource will generate additional received signals at adjacent time-frequency resource locations. , causing interference to the useful received signal.
  • OFDM/OQAM Orthogonal Frequency Division Multiplexing (OFDM) / Offset Quadrature Amplitude Modulation (OQAM).
  • OFDM/OQAM differs from OFDM in that OFDM/OQAM systems transmit pure real or pure imaginary OQAM symbols and map them on time-frequency resource elements in a real virtual alternating pattern.
  • the interference of the transmitted symbol to the received signal always appears on the imaginary or real part opposite the transmitted symbol. Therefore, if the channel can remain unchanged in the time domain and the frequency domain, the interference can be eliminated by a real imaginary separation operation after channel equalization.
  • the transmitted pilot symbols are subject to the inherent interference of the surrounding symbols at the receiving end. Therefore, it is necessary to design a pilot scheme to solve the interference problem in the channel estimation.
  • the pilots of the commonly used FBMC channel estimation are mainly scattered. Scattered Pilots.
  • the pilot symbols of the decentralized pilots are scattered and inserted into the middle of the data symbols. Therefore, how to eliminate the inherent interference of the surrounding data symbols to the pilot symbols is a key problem to be solved by the channel estimation.
  • the scheme of the decentralized pilot is mainly implemented by using an interference cancellation method. Specifically, by inserting an auxiliary pilot around the pilot symbol, the inherent interference of the surrounding data symbols with the pilot symbols is 0, thereby Channel estimation can be performed without interference.
  • the embodiments of the present invention provide a method for transmitting pilot symbols, a receiving method, a transmitter, and a receiver, which can be used for channel estimation with severe channel variation.
  • an embodiment of the present invention provides a method for transmitting a pilot symbol, including:
  • a filter bank multicarrier FBMC signal mapped with the pilot symbols, wherein the pilot symbols are mapped to the second frequency interval;
  • the FBMC signal of the pilot symbol is transmitted to a receiver to cause the receiver to extract the pilot symbols from the FBMC signal for channel estimation.
  • the mapping the OQAM symbols on each subband to each subcarrier includes:
  • the mapping the nth OQAM symbol on the Xth subband to the yth subcarrier and The (n+1)th OQAM symbol on the Xth subband is mapped onto the (y+1)th subcarrier Thereafter, the first frequency interval ⁇ between the yth subcarrier and the (y+1)th subcarrier is implemented by:
  • the mapping the OQAM symbols on each sub-band to each sub-carrier separately includes:
  • the interval (m + 1) ⁇ is achieved as follows:
  • k is the overlap factor of the prototype filter
  • p is the out-of-band rejection factor of the prototype filter
  • the OQAM on each subband Before the symbols are respectively mapped to the respective subcarriers further includes:
  • guard band interval Obtaining the guard band interval according to an overlap factor and an outband suppression factor of the prototype filter and the first frequency interval, where the guard band interval is obtained by:
  • G is the guard band interval
  • the overlap factor of the prototype filter is
  • P is an out-of-band rejection factor of the prototype filter
  • the ⁇ is the first frequency interval.
  • Time domain misalignment is performed on the time domain signal to which the pilot symbol is mapped, to obtain an FBMC signal to which the pilot symbol is mapped.
  • the mapping, the time-domain contiguous pilot symbols into the frequency domain signal includes:
  • the mapping of pilot symbols is performed every 2K symbol lengths of the FBMC signal, which is the overlap factor of the prototype filter.
  • the mapping, the time-domain continuous pilot symbols into the frequency domain signal includes:
  • the time domain contiguous pilot symbols are mapped to the center frequency position of the second frequency interval.
  • the FBMC signal to which the pilot symbol is mapped is obtained.
  • the generating the FBMC signal by using the frequency domain signal includes:
  • the time domain misalignment is superposed on the time domain signal to obtain the FBMC signal.
  • the generating the FBMC signal by using the frequency domain signal includes:
  • the time domain signals are time-domain misaligned to obtain the FBMC signal.
  • the pilot symbols remain unchanged in a symbol length of at least two FBMC signals.
  • the embodiment of the present invention further provides a method for receiving a pilot symbol, including: receiving a filter bank multi-carrier FBMC signal sent by a transmitter, where the FBMC signal maps a time-continuous pilot symbol, the FBMC a first frequency interval between adjacent subcarriers in the same subband of the signal, a second frequency interval between adjacent subcarriers between adjacent two subbands of the FBMC signal, and the second frequency The interval is greater than the first frequency interval;
  • a pilot symbol is extracted from a second frequency interval in the FBMC signal after the DFT; and the extracted pilot symbol is used for channel estimation.
  • the method further includes:
  • the received FBMC signal is truncated according to the symbol length of the FBMC signal to obtain a truncated FBMC signal;
  • Performing a discrete Fourier transform DFT on the FBMC signal including:
  • DFT is performed on the truncated FBMC signal.
  • the method before performing the discrete Fourier transform DFT on the FBMC signal, the method further includes:
  • Performing a discrete Fourier transform DFT on the FBMC signal including:
  • DFT is performed on the FBMC signal after windowing or filtering.
  • an embodiment of the present invention further provides a transmitter, including:
  • a symbol generation module configured to generate offset quadrature amplitude modulation included on at least two subbands OQAM symbol
  • a symbol mapping module configured to map the OQAM symbols on each subband to each subcarrier separately to obtain a frequency domain signal, where adjacent subcarriers in the same subband have a first frequency interval, and two adjacent subcarriers a second frequency interval between adjacent subcarriers between the bands, and the second frequency interval is greater than the first frequency interval;
  • a signal generating module configured to generate, by using a time domain continuous pilot symbol and the frequency domain signal, a filter bank multicarrier FBMC signal mapped with the pilot symbol, where the pilot symbol is mapped to the second frequency Interval
  • a sending module configured to send, to the receiver, the FBMC signal to which the pilot symbol is mapped, so that the receiver extracts the pilot symbol from the FBMC signal for channel estimation.
  • the symbol mapping module is specifically configured to use the nth OQAM symbol on the Xth subband. Mapping to the yth subcarrier; mapping the (n+1)th OQAM symbol on the Xth subband to the (y+1)th subcarrier;
  • the first y subcarrier and the (y+1)th subcarrier have a first frequency interval ⁇ , and the X refers to any one of the at least two subbands, and the ⁇ Refers to any one of the OQAM symbols on the Xth subband, the nth OQAM symbol and the (n+1)th OQAM symbol are two adjacent OQAM symbols on the Xth subband, the x , y, n are positive integers.
  • the frequency interval ⁇ is achieved as follows:
  • the symbol mapping module is specifically configured to map the last OQAM symbol on the X-th sub-band. To the zth subcarrier; the first OQAM on the (x+1)th subband The symbol is mapped to the (z+1)th subcarrier;
  • the zth subcarrier and the (z+1)th subcarrier have a second frequency interval (m+1) A
  • the ⁇ represents the first frequency interval
  • the m A is a guard band
  • the interval the m is a number greater than 0, and the x and z are positive integers.
  • the interval (m + 1) ⁇ is achieved as follows:
  • k is the overlap factor of the prototype filter
  • p is the out-of-band rejection factor of the prototype filter
  • the transmitter further includes: protection a band interval acquisition module, configured to: before the symbol mapping module maps OQAM symbols on each subband to respective subcarriers, according to an overlap factor and an outband suppression factor of the prototype filter and the first frequency interval
  • protection a band interval acquisition module configured to: before the symbol mapping module maps OQAM symbols on each subband to respective subcarriers, according to an overlap factor and an outband suppression factor of the prototype filter and the first frequency interval
  • the guard band interval wherein the guard band interval is obtained by:
  • the G is the guard band interval
  • the overlap factor of the prototype filter the P is an out-of-band rejection factor of the prototype filter
  • the ⁇ is the first frequency interval.
  • the signal generating module includes: filtering And performing frequency domain filtering on the frequency domain signal;
  • a first pilot mapping module configured to map time-domain contiguous pilot symbols into the frequency domain signal, where the pilot symbols are mapped to a second frequency interval of the frequency domain signal
  • a first discrete Fourier transform module configured to perform an inverse discrete Fourier transform IDFT on a frequency domain signal to which the pilot symbol is mapped, to obtain a time domain signal with the pilot symbol mapped thereon;
  • a first misalignment superposition module configured to perform time domain misalignment superposition on the time domain signal to which the pilot symbol is mapped, to obtain an FBMC signal to which the pilot symbol is mapped.
  • the first pilot mapping module is specifically used to perform the symbol length of every 2K FBMC signals.
  • the mapping of pilot symbols which is the overlap factor of the prototype filter.
  • the first pilot mapping module is specifically configured to map time-domain continuous pilot symbols to the The center frequency position of the second frequency interval.
  • the signal generating module includes:
  • An FBMC generating module configured to generate the FBMC signal by using the frequency domain signal
  • a second pilot mapping module configured to map time-domain continuous pilot symbols to respective corresponding second frequency intervals, to generate a signal mapped on the second frequency interval
  • a signal combining module configured to combine the FBMC signal and the signal mapped on the second frequency interval to obtain the FBMC signal with the pilot symbol mapped.
  • the FBMC generating module includes:
  • a filter configured to perform frequency domain filtering on the frequency domain signal
  • a second discrete inverse Fourier transform module configured to perform a discrete Fourier transform (IDFT) on the frequency domain filtered frequency domain signal to obtain a time domain signal;
  • IDFT discrete Fourier transform
  • a second misalignment superposition module configured to perform time domain misalignment superposition on the time domain signal to obtain the FBMC signal.
  • the FBMC generating module includes:
  • An inverse Fourier transform module configured to perform inverse Fourier transform on the frequency domain signal to obtain a time domain signal
  • a filtering module configured to perform filtering on the multi-phase network by using the time domain signal to obtain a filtered time domain signal
  • a third misalignment superposition module configured to perform time domain misalignment superposition on the time domain signal to obtain the FBMC signal.
  • the pilot symbol keeps a value unchanged within a symbol length of the at least two FBMC signals.
  • the embodiment of the present invention further provides a receiver, including:
  • a receiving module configured to receive a filter bank multi-carrier FBMC signal sent by the transmitter, where the FBMC signal maps a continual pilot symbol in a time domain, and the first sub-carrier in the same sub-band of the FBMC signal has a first a frequency interval, a second frequency interval between adjacent subcarriers between adjacent two subbands of the FBMC signal, and the second frequency interval is greater than the first frequency interval;
  • a discrete Fourier transform module configured to perform a discrete Fourier transform DFT on the FBMC signal
  • a pilot extraction module configured to extract a pilot symbol from a second frequency interval in the FBMC signal after the DFT
  • a channel estimation module configured to perform channel estimation by using the extracted pilot symbols.
  • the receiver in a first possible implementation manner of the fourth aspect, the receiver,
  • the FBMC intercepting module is configured to: after receiving, by the receiving module, the FBMC signal sent by the transmitter, intercepting the received FBMC signal according to a symbol length of the FBMC signal, to obtain a truncated FBMC signal;
  • the discrete Fourier transform module is specifically configured to perform DFT on the truncated FBMC signal.
  • the receiver in a second possible implementation manner of the fourth aspect, the receiver,
  • a FBMC processing module configured to perform windowing processing or filtering processing on the FBMC signal before performing a discrete Fourier transform DFT on the FBMC signal by the discrete Fourier transform module; the discrete Fourier transform module, Specifically, it is used to perform DFT on the FBMC signal after the windowing process or after the filtering process.
  • the embodiments of the present invention have the following advantages:
  • the OQAM symbols on each subband are mapped to the respective subcarriers to obtain a frequency domain signal, where adjacent in the same subband There is a first frequency interval between the subcarriers, a second frequency interval between adjacent subcarriers between two adjacent subbands, and the second frequency interval is greater than the first frequency interval, and then the pilot symbols are continuous in the time domain.
  • Generating a FBMC signal with pilot symbols mapped to the frequency domain signal, and finally mapping The FBMC signal with pilot symbols is transmitted to the receiver to cause the receiver to extract pilot symbols from the FBMC signal for channel estimation.
  • the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency isolation between two adjacent sub-bands, so that the interference of the FBMC signals to the pilot symbols can be avoided, so that mutual interference of channels generated by adjacent sub-bands due to different channels can be eliminated. Off, so the pilot symbols can be applied to channel estimation of the transmit channel in a scene with severe channel variations.
  • FIG. 1 is a schematic block diagram of a method for transmitting a pilot symbol according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a data subcarrier carrying a FBMC signal and a pilot subcarrier carrying a pilot symbol according to an embodiment of the present invention
  • Schematic diagram of frequency domain amplitude influence schematic diagram of implementation of canceling interference between pilot symbols and frequency domain signals after interval and before insertion of guard band interval; schematic diagram of implementation manner of inserting pilot subcarriers;
  • FIG. 4 is a schematic diagram of an implementation of a plurality of time domain symbols formed by pilot symbols
  • FIG. 5 is a schematic diagram of an implementation manner of mapping pilot symbols to a second frequency domain interval in an FBMC signal according to an embodiment of the present invention
  • FIG. 6 is a schematic block diagram of a method for receiving a pilot symbol according to an embodiment of the present invention
  • FIG. 7 is a schematic diagram of time domain characteristics of a filter according to an embodiment of the present invention
  • 7-B are schematic diagrams showing spectral characteristics of a filter according to an embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a method for transmitting a pilot symbol implemented by a transmitter according to an embodiment of the present invention
  • FIG. 9 is a schematic diagram of an application scenario for inserting a guard band interval between adjacent subbands according to an embodiment of the present invention
  • FIG. 10 is a schematic diagram of another method for transmitting a pilot symbol implemented by a transmitter according to an embodiment of the present invention.
  • FIG. 11 is a schematic diagram of another method for transmitting a pilot symbol implemented by a transmitter according to an embodiment of the present invention
  • 12-A is a schematic structural diagram of a transmitter according to an embodiment of the present invention
  • FIG. 12-B is a schematic structural diagram of another transmitter according to an embodiment of the present invention
  • FIG. 12-C is a schematic diagram of an embodiment of the present invention
  • FIG. 12-D is a schematic structural diagram of another signal generation module according to an embodiment of the present invention
  • FIG. 12-E is a schematic diagram of an FBMC generation module according to an embodiment of the present invention
  • FIG. 12-F is a schematic structural diagram of another FBMC generation module according to an embodiment of the present invention
  • 13-A is a schematic structural diagram of a receiver according to an embodiment of the present invention.
  • FIG. 13-B is a schematic structural diagram of another receiver according to an embodiment of the present invention
  • FIG. 13 is a schematic structural diagram of another receiver according to an embodiment of the present invention
  • FIG. 14 is a schematic diagram of an embodiment of the present invention.
  • FIG. 15 is a schematic structural diagram of another receiver according to an embodiment of the present invention. detailed description
  • the embodiments of the present invention provide a method for transmitting pilot symbols, a receiving method, a transmitter, and a receiver, which can be used for channel estimation with severe channel variation.
  • the FBMC signal will have different degrees of mutual interference between adjacent subcarriers and adjacent FBMC symbols. Disturb.
  • the transmitted signal on any one of the time-frequency resources will generate an additional received signal at the adjacent time-frequency resource location, causing interference to the useful received signal.
  • This kind of interference can be represented by the filter adapter's multiplexer response (English full name Transmultiplexer Response, TMUX for short).
  • the TMUX response reflects the transmission signal to the periphery at a certain time-frequency position under ideal channel conditions. The degree of diffusion at the frequency position.
  • Table 1 shows an example of a typical TMUX response table, in Table 1.
  • the row represents the subcarrier number and the column represents the number of the FBMC signal.
  • the coefficients in the table represent the coefficients of the received signal generated by the signal transmitted by the center position (i.e., subcarrier 0 and signal 0) at the corresponding subcarriers and signal positions. For example, assuming that the transmitted signal at the center position is, the coefficient of the position of the subcarrier i and the signal j is ⁇ 3 ⁇ 4, then a received signal a y x ⁇ is generated at the position of the subcarrier signal j. If no action is taken, this signal will interfere with the reception of the wanted signal transmitted at that location, which is usually an inherent characteristic of the FBMC signal.
  • the transmitted pilot symbols are subject to the inherent interference of the surrounding FBMC signals at the receiving end.
  • the OQAM symbol transmitted at the (subcarrier 0, signal 0) position in Table 1 is a pure real symbol ⁇ . . ,, according to the law of alternating real and imaginary numbers, then the OQAM symbol transmitted at the position of (subcarrier 0, signal 1) is a pure imaginary number, denoted as 1 ). Specifically, to 3 ⁇ 4 .
  • the interference at other locations is temporarily ignored, and the interference at other locations can be analyzed in the same way.
  • the embodiment of the present invention provides a method for transmitting pilot symbols in the FBMC signal and a receiving method, which can be applied to a scene of channel change, and then the pilot symbol first.
  • the sending method is described in detail:
  • a method for transmitting a pilot symbol may specifically include the following steps:
  • Quadrature Amplitude Modulation English abbreviation OQAM
  • a subband (English full name subband) refers to a frequency resource composed of a plurality of consecutive subcarriers.
  • a plurality of OQAM symbols generated by the transmitter are carried on the respective sub-bands.
  • the OQAM symbols on each subband are respectively mapped to the respective subcarriers to obtain a frequency domain signal, where the adjacent subcarriers in the same subband have a first frequency interval between adjacent two subbands. There is a second frequency interval between adjacent subcarriers, and the second frequency interval is greater than the first frequency interval.
  • the transmitter after the transmitter generates the OQAM symbol, the transmitter performs subcarrier mapping on the OQAM symbol, and the transmitter maps the OQAM symbols on each subband to each subcarrier respectively, and after the mapping is completed, each sub A fixed interval is maintained between the carriers, that is, as long as there is an interval between adjacent two subcarriers (also referred to as subcarrier spacing), and there is a first between adjacent subcarriers in the same subband.
  • the frequency interval has a second frequency interval between adjacent subcarriers between two adjacent subbands, and the second frequency interval is greater than the first frequency domain interval.
  • the second frequency interval is a sum of the first frequency interval and the guard band interval
  • the guard band interval is a fractional multiple of the first frequency interval
  • the first frequency interval between adjacent subcarriers in the same subband is smaller than the second frequency interval between adjacent subcarriers between adjacent subbands, and the second frequency interval is numerically reduced.
  • the first frequency interval is equal to the guard band interval.
  • the second frequency interval is an integer multiple of the first frequency interval, for example, the value of the second frequency interval is 2 times or 3 times of the value of the first frequency interval.
  • step 102 mapping the OQAM symbols on each subband to each subcarrier separately may include two situations: one is to map the OQAM symbols on the same subband to the subcarriers, The other is to map the OQAM symbols carried on the adjacent subbands onto the subcarriers. Specifically, for the OQAM symbols that belong to the same subband, step 102 maps the OQAM symbols on each subband to each subcarrier, and may include the following steps:
  • the transmitter may separately map all the OQAM symbols generated in step 101.
  • the sub-band of the subcarrier mapping performed by the transmitter is represented by X. If the OQAM symbol generated by the transmitter is carried on four sub-bands, Then, the value of X can be 1 or 2 or 3 or 4, and any OQAM symbol on the Xth subband is represented by n. If the transmitter carries 5 OQAM symbols on the Xth subband, then n The value may be 1 or 2 or 3, etc., (n+1) may represent an OQAM symbol adjacent to n, and y shall be used to represent a subcarrier to which the nth OQAM symbol on the Xth subband is mapped.
  • first mapping the first OQAM symbol on the first subband to the yth subcarrier, and then the first subband.
  • the second OQAM symbol is mapped onto the (y+1)th subcarrier, ... until the 5th OQAM symbol on the 1st subband is mapped to the (y+4)th subcarrier.
  • Subcarrier mapping is performed on OQAM symbols belonging to the same subband according to the manner described above, and adjacent subcarriers in the same subband have the same interval value, and the interval value is a first frequency interval, which can be represented by ⁇ .
  • mapping the nth OQAM symbol on the Xth subband to the yth subcarrier and mapping the (n+1)th OQAM symbol on the Xth subband to After the (y+1)th subcarrier, in the frequency domain, the first frequency interval ⁇ between the yth subcarrier and the (y+1)th subcarrier is implemented as follows: Inserting (k - 1) 0s between the nth OQAM symbol and the (n+1)th OQAM symbol;
  • the transmitter when the transmitter performs subcarrier mapping, for the case where the OQAM symbols belonging to the same subband are respectively mapped to the subcarriers, the adjacent subcarriers (ie, the yth subcarrier and the (y+1)th subcarrier)
  • the first frequency interval between the two is achieved by inserting (k - 1 ) 0 between the nth OQAM symbol and the (n+1)th OQAM symbol, where k is the prototype filter set by the transmitter The overlap factor.
  • the step 102 maps the OQAM symbols on each sub-band to the respective sub-carriers, which may include the following steps:
  • the transmitter may separately map all the OQAM symbols generated in step 101.
  • the sub-band of the subcarrier mapping performed by the transmitter is represented by X. If the OQAM symbol generated by the transmitter is carried on four sub-bands, Then, the value of X may be 1 or 2 or 3.
  • the subband adjacent to X is represented by (x+1), and if the last OQAM symbol on the Xth subband is mapped to the zth subcarrier, The first OQAM symbol on the (x+1)th subband adjacent to the Xth subband can be mapped onto the (z+1)th subcarrier.
  • the implementation scenarios of the OQAM symbols belonging to the two subbands are as follows: The fifth on the first subband The OQAM symbol is mapped onto the zth subcarrier, and then the first OQAM symbol on the second subband is mapped onto the z+1th subcarrier.
  • the subcarrier mapping is performed on the OQAM symbols belonging to the two subbands in the manner described above, and the adjacent subcarriers belonging to the two subbands have the same interval value, and the interval value is the second frequency interval, which can be used ( m+ l)A indicates that m represents a number greater than 0, and m A can represent the guard band interval. Further, m can be an integer or a fraction.
  • the last OQAM on the Xth subband After the symbol is mapped onto the zth subcarrier and the first OQAM symbol on the (x+1)th subband is mapped onto the (z+1)th subcarrier, from the frequency domain, the zth subcarrier and the third A second frequency interval (m + 1) ⁇ between (z+1) subcarriers is achieved as follows:
  • k is the overlap factor of the prototype filter
  • p is the out-of-band rejection factor of the prototype filter
  • the adjacent subcarriers ie, the zth subcarrier and the (z+1)th subcarrier
  • the second frequency interval between ( ) is inserted by (k + p - 1 ) between the last OQAM symbol on the Xth subband and the first OQAM symbol on the (x+1)th subband Implemented by 0, where k is the overlap factor of the prototype filter set by the transmitter and p is the out-of-band rejection factor of the prototype filter.
  • the out-of-band rejection factor is a parameter reflecting the out-of-band suppression effect of the prototype filter.
  • the method for determining the out-of-band rejection factor is: if (k+p-1) 0s are inserted between two adjacent OQAM symbols, and after frequency domain filtering, the energy of the spectrum of the adjacent two OQAM symbols is mainly If part of the overlap does not occur, then p is considered to be a reasonable out-of-band inhibitor. Alternatively, the main portions of the energy of the spectrum of the adjacent two OQAM symbols may not be overlapped, and the value of a certain frequency interval is taken as the value of p. Since the pilot signal will be inserted at the second frequency interval, a part of the vacant frequency interval can more effectively protect the pilot signal from the OQAM symbol from interfering with each other.
  • a first frequency interval between adjacent subcarriers in the same subband and a second frequency interval between adjacent subcarriers between adjacent two subbands may also be as follows The method is implemented by: first inserting a first frequency interval between all adjacent subcarriers, that is, inserting a first frequency interval between the same subband or between two subbands, and then subdividing into two sub-intervals The adjacent subcarriers between the bands are reinserted into the guard band interval, so the guard band interval plus the first frequency interval can obtain the second frequency interval.
  • the transmitter maps all OQAM symbols to respective subcarriers, all adjacent subcarriers have a first frequency interval, and then the transmitter is adjacent between adjacent subbands in the FBMC signal.
  • the guard band interval is one
  • the value is the interval value of the first frequency interval, and the interval value is used to protect the OQAM symbols on the adjacent two sub-bands from mutual interference. Since the transmitter inserts a guard band interval between different sub-bands, the guard band interval can effectively isolate adjacent sub-bands, and the spectrum of adjacent sub-bands in the guard band interval can be non-overlapping to achieve approximately orthogonality.
  • the guard band interval can eliminate mutual interference caused by adjacent subbands due to different channels, and since the guard band interval is a multiple of the first frequency interval, and does not exceed one complete adjacent subcarrier interval, Therefore, the guard band interval of the fractional multiple reduces the occupation of spectrum resources.
  • the last OQAM symbol of the Xth subband is mapped to the zth subcarrier
  • the first OQAM symbol of the (x+1)th subband is mapped to the (z+1)th subcarrier, which belongs to two Insert ⁇ between the zth subcarrier and the (z+1)th subcarrier of each subband, and then insert ⁇ ⁇ / ⁇ between the second subcarrier and the (z+1)th subcarrier, where ⁇ ⁇
  • m is a number greater than zero.
  • FIG. 2 is a schematic diagram of an implementation manner of inserting a guard band interval between adjacent subcarriers between two adjacent subbands according to an embodiment of the present invention, in time domain (t).
  • the Xth subband and the (x+1)th subband are continuously distributed, and a guard band interval is inserted between the Xth subband and the ((+1)th subband in the frequency domain (f), visible, in different sub-bands Mutual interference caused by adjacent subbands between the bands due to different channels is eliminated.
  • the guard band interval is a fractional multiple of the first frequency interval, where the fractional multiple refers to a score greater than 0, and the fractional multiple is also considered to be a pure fraction.
  • the value of the guard band interval is a multiple of the first frequency interval.
  • Step 102 Before mapping the OQAM symbols on each subband to respective subcarriers, acquiring the guard band interval according to an overlap factor of the prototype filter and an outband suppression factor and the first frequency interval, where The guard band interval is as follows: P
  • the G is the guard band interval
  • the overlap factor of the prototype filter the P is an out-of-band rejection factor of the prototype filter
  • the ⁇ is the first frequency interval.
  • the transmitter is equipped with a filter, and the transmitter can determine the value of the guard band interval according to the overlap factor of the prototype filter and the out-of-band rejection factor and the first frequency interval, wherein the value of the overlap factor It is determined by the filter provided by the transmitter that the out-of-band suppression factor refers to the degree of suppression of the signal by the filter beyond the passband, and the transmitter can use the relevant parameters of the filter to determine the value of the guard band interval, in the embodiment of the present invention.
  • the manner in which the guard band interval is obtained may be other than the fraction of the first frequency interval.
  • the transmitter may preset one point. A multiple of the value is used as the guard band interval. After the transmitter maps all the OQAM symbols to the respective subcarriers, the preset guard band interval can be inserted between adjacent subcarriers of the adjacent subband.
  • a first frequency interval (which may be referred to as a subcarrier interval, for example, ⁇ ) between adjacent subcarriers in the same subband is fixed.
  • 103 Generate, by using a time domain continuous pilot symbol and a frequency domain signal, a FBMC signal with a pilot symbol mapped, wherein the pilot symbol is mapped to the second frequency interval.
  • the transmitter may generate the FBMC signal with the pilot symbol mapped by using the time domain continuous pilot symbol and the frequency domain signal obtained in step 102.
  • the pilot symbols are mapped to a second frequency interval in the FBMC signal. That is, the time-domain contiguous pilot symbols are inserted into the generated FBMC signal.
  • the time-domain contiguous pilot symbols in the embodiment of the present invention are mapped to the second frequency interval in the FBMC signal, and the pilot symbols are The second frequency interval mapped to is located on the frequency sample between the adjacent two sub-bands, and then the FBMC signal with the pilot symbol mapped is sent out in the subsequent step, and the pilot symbol can be transmitted together with the FBMC signal.
  • the pilot symbols are extracted from the FBMC signal by the receiver for channel estimation. Since the pilot symbols are inserted at a second frequency position between adjacent two sub-bands in the FBMC signal, the pilot symbols and FBMC can be separated by isolation of the second frequency interval between adjacent sub-bands.
  • the signals are isolated, so that the interference of the FBMC signal to the pilot symbols can be avoided, so that the mutual interference of the adjacent sub-bands due to the different channels can be removed, so the pilot symbols can be applied to the scene with severe channel changes.
  • Channel estimation for the transmit channel is provided.
  • the step 103 generates the FBMC signal with the pilot symbol mapped by using the pilot symbols and the frequency domain signals in the time domain, which may specifically include the following steps:
  • A3 performing an inverse discrete Fourier transform (English full name Inverse Discrete Fourier Transform, IDFT) on the frequency domain signal to which the pilot symbol is mapped, to obtain a time domain signal with the pilot symbol mapped thereon;
  • IDFT Inverse Discrete Fourier Transform
  • A4. Perform time domain misalignment superposition on the time domain signal with the pilot symbol mapped to obtain an FBMC signal with the pilot symbol mapped.
  • the transmitter performs frequency domain filtering on the frequency domain signal to obtain a frequency domain filtered frequency domain signal.
  • the OQAM symbols carried on the multiple sub-bands constitute an FBMC signal, and each FBMC signal includes an OQAM symbol carried on multiple sub-bands.
  • the transmitter performs frequency domain filtering on the frequency domain signal, specifically Implemented by a filter configured in the transmitter.
  • the transmitter may map the time domain continuous pilot in the frequency domain filtered frequency domain signal.
  • the symbol in the embodiment of the present invention is mapped to the second frequency interval between adjacent two subbands in the frequency domain signal, that is, the frequency position to which the pilot symbol is mapped is located.
  • step A3 performs IDFT on the frequency domain signal with the pilot symbol mapped to the time-domain continuous pilot symbol inserted in the frequency domain signal.
  • the time domain signal with the pilot symbol is obtained, and finally, by step A4, the misalignment of the time domain signal is superimposed, and the FBMC signal with the pilot symbol is mapped.
  • the transmitter can transmit the pilot symbols together with the FBMC signal, and the pilot extracts the pilot symbols from the FBMC signal for channel estimation.
  • the time domain contiguous pilot symbols are mapped to the second frequency interval between two adjacent subbands in the FBMC signal, that is, the pilot symbols are inserted between adjacent two subbands in the FBMC signal, through adjacent subcarriers.
  • Isolation of the frequency position between the bands isolates the pilot symbols from the FBMC signal, thereby avoiding interference of the FBMC signal to the pilot symbols, and for different subbands due to different letters
  • the interference of the FBMC signal to the pilot symbol is not generated, so it can be applied to a scene with a severe channel change.
  • the data subcarrier carrying the FBMC signal and the pilot subcarrier carrying the pilot symbol are provided according to an embodiment of the present invention.
  • Schematic diagram of the influence of the domain amplitude where the data subcarrier carrying the FBMC signal is indicated by a broken line, and the pilot subcarrier carrying the pilot symbol is indicated by a solid line, as shown, since the pilot symbol is mapped between adjacent two subbands in the FBMC signal
  • the frequency domain response of the data subcarrier is 0 or approximately 0 at the pilot subcarrier, so the FBMC signal does not interfere with the pilot symbols.
  • the method for transmitting pilot symbols in the FBMC signal may further include the following steps: A pilot subcarrier is inserted between adjacent two subbands in the frequency domain signal, and a frequency position of the pilot subcarrier is located in a second frequency domain interval between two adjacent subbands.
  • the pilot subcarriers may be inserted between two adjacent subbands in the frequency domain signal, where the pilot subcarriers specifically refer to the pilot symbols that can be used to carry the pilot symbols.
  • the pilot subcarrier is inserted in a second frequency interval between two adjacent subbands in the frequency domain signal, that is, the frequency position of the pilot subcarrier is located between two adjacent subbands The frequency is on the sample point.
  • step A2 maps the pilot symbols in the time domain to the frequency domain signal, and specifically includes the following steps:
  • the time domain contiguous pilot symbols are mapped to the center frequency position of the second frequency interval.
  • the center point between two adjacent sub-bands in the frequency domain signal is the center frequency position.
  • the frequency position of the pilot sub-carrier can be the center frequency position between the adjacent two sub-bands, only the pilot.
  • the frequency position of the pilot subcarrier is located at a frequency sample between the adjacent two subbands.
  • a pilot subcarrier is inserted between two adjacent subbands, assuming that the frequency of the last subcarrier of the first subband is the frequency of the 0th subcarrier of the i+1th subband is /. '- 1 , then the frequency of the inserted pilot subcarrier is between / ⁇ port/.
  • the frequency of the pilot subcarrier can be selected as the sum of /.”, that is, (/ ⁇ + ⁇ ' +1 ) / 2 , can directly generate a single carrier symbol of the center frequency point As a continuous pilot symbol, for example, one can be generated
  • the time domain signal is 1 + /. ' +1 ) ⁇ /2], where ⁇ denotes the first pilot subcarrier,
  • / ⁇ indicates the pilot symbol carried on the subcarrier. It can be understood that the expression of the time domain signal is only an example, and other description manners may be used in a specific application scenario, which is not limited herein.
  • the frequency domain signal is only mapped to a part of the subcarriers, there must be idle subcarriers in the frequency domain signal, and these free subcarriers can be used to map the time domain continuous pilot symbols.
  • the frequency domain signals are mapped to which subcarriers of all subcarriers, which subcarriers do not map the frequency domain signals, and the number and location of each subcarrier are generally determined according to overhead, channel model, channel estimation performance, and all subcarriers are determined.
  • the OQAM symbols of each subband can be mapped to a part of the subcarriers, and the obtained idle subcarriers in the frequency domain signal can be used to map the time domain continuous pilot symbols. Since the frequency domain signal does not occupy all the subcarriers, the idle subcarriers between the adjacent two subbands can isolate the last generated FBMC signal, avoiding data interference in the FBMC signal, and the pilot symbols are mapped to On these idle subcarriers, interference of the FBMC signal with the pilot symbols can also be avoided.
  • the present invention before the frequency domain filtering is performed on the frequency domain signal in step A1, the present invention
  • the method can also include the following steps:
  • the frequency position of the pilot subcarrier is at a guard band interval.
  • the transmitter can further insert the guard band interval between the adjacent two subbands, wherein
  • the guard band interval is an interval value which is a fractional multiple of the first frequency interval.
  • the interval value is used to protect the OQAM symbols on the adjacent two sub-bands from mutual interference and the frequency of the pilot sub-carriers.
  • the location is on the guard band interval, the pilot symbols are mapped onto the pilot subcarriers, and the frequency locations to which the pilot symbols are mapped are on the guard band spacing.
  • the guard band interval can eliminate mutual interference caused by adjacent subbands due to different channels, and since the guard band interval is a fractional multiple of the interval between two adjacent subcarriers, there is no more than one complete phase.
  • the adjacent subcarrier spacing, so the fractional guard band spacing reduces the occupation of spectrum resources.
  • a spectrum of subband 1 is indicated by a solid line, and a subband 2 is indicated by a broken line.
  • the spectrum of the spectrum, the left half of Figure 3-A is a schematic diagram of the spectral overlap between the subband 1 and the subband 2 before the insertion of the guard band interval.
  • the right half of Fig. 3-A is the mutual interference after the insertion of the guard band interval.
  • the spectrum does not overlap the schematic.
  • the left half of Figure 3-B is a schematic diagram of the spectrum overlap without interference after the guard band interval is inserted.
  • the right half of Figure 3-B For the schematic diagram of inserting pilot subcarriers on guard band intervals, pilot symbols can be mapped onto pilot subcarriers by inserting pilot subcarriers inserted between adjacent subbands, from FIG. It can be seen from -B that the frequency position of the pilot symbol is at the guard band interval, and the FBMC signal is separated from the pilot symbol by the guard band interval, so that the interference of the FBMC signal to the pilot symbol can be avoided.
  • the pilot symbols generated by the transmitter remain unchanged in the symbol length of at least two FBMC signals, which is understandable.
  • the value of the pilot symbol mentioned here remains the same, except that the value of the pilot symbol remains unchanged for a period of time (eg, within the symbol length of two FBMC signals), rather than never change.
  • the value of the pilot symbol may remain unchanged in one subframe, but may be different in different subframes.
  • the value of the pilot symbol may remain the same in different subframes, at least guaranteed.
  • the value of the pilot symbol in one subframe remains unchanged.
  • the frequency of the OFDM symbol is represented by a SINC function
  • the pilot symbol is a FBMC signal.
  • the interference avoidance is implemented by the zero point of the SINC function.
  • the insertion of the pilot subcarrier is before the IDFT. If the pilot subcarrier is viewed alone, this process is similar to the OFDM transform. According to the basic principle of the OFDM transform, the pilot subcarrier is known.
  • the frequency domain response is represented by a SINC function, and the SINC function is characterized by a response of 0 at the frequency position of the other subcarriers except that the response of the center data is 1. This is the OFDM.
  • the frequency position of the frequency domain sample of the FBMC signal is exactly the frequency position where the SINC function 0 point of the pilot symbol is located. Therefore, if the pilot subcarrier always appears as a SINC function, Avoid interference from pilot symbols to FBMC signals.
  • the symbol length of the pilot is 2K times the symbol interval of the FBMC signal, where K refers to the overlap factor of the prototype filter provided by the transmitter, so when the receiver receives the FBMC signal.
  • K refers to the overlap factor of the prototype filter provided by the transmitter
  • the pilot symbol and the FBMC signal appear differently, because the pilot symbol takes values in at least one subframe, that is, the value of the pilot symbol always repeats the previous value, because The pilot symbols are not changed in time, so the time domain symbols formed by the pilot symbols are equivalent to being repeated all the time. As shown in FIG.
  • a schematic diagram of an implementation manner of a plurality of time domain symbols formed by pilot symbols wherein a first time domain symbol formed by a pilot symbol is represented as S 1 S 2 , ⁇ ⁇ , S N , S N+1 , ⁇ , SKM, the second time domain symbol formed by the pilot symbols, and the same as the first time domain symbol, can also be expressed as S 1 S 2 ,•••,S n , S n+1 , " KM, a total of KM samples, then the KM samples are always transmitting repeatedly, K is the overlap factor of the prototype filter equipped with the transmitter, and M is the subcarrier in the frequency domain.
  • the value taken out is always equivalent to S 1 S 2 , " ⁇ SKM cyclic shift.
  • S n+1 , S n+2 , ⁇ , SKM, SI, S 2 , ⁇ , S n which is the original data Sj, S 2 , ⁇ , SKM
  • the result of the n-point cyclic shift to the left is to extract the KM sample pilot symbols and the data symbol i, the data symbol i+l, and the data symbol i+2, and the difference between the two data symbols is M/2. ⁇ , where i is a positive integer, and the data symbol refers to the FBMC signal, because the cyclic shift of the time domain is equivalent to the phase shift in the frequency domain, so the KM samples taken at the arbitrary position as the starting point are The performance in the frequency domain is still the SINC function, which is equivalent to multiplying a phase shift factor on the subcarrier.
  • step A2 maps time domain contiguous pilot symbols into the frequency domain signal, including:
  • the mapping of pilot symbols is performed every 2K symbol lengths of the FBMC signal, which is the overlap factor of the prototype filter.
  • mapping every 2K FBMC signals mapping pilot symbols to second of frequency domain signals
  • K is the overlap factor of the prototype filter.
  • the pilot letter The symbol length of the number is 2K times the symbol interval of the FBMC signal.
  • the pilot symbols can be mapped once every 2K symbols of the FBMC signal, and other times when the pilot symbols are not transmitted. Fill with 0.
  • mapping may be performed once every 2K FBMC signals when the pilot symbols are mapped into the frequency domain signal, because the pilot symbols
  • the symbol length is 2K times the symbol interval of the FBMC signal, so that the pilot symbols can be effectively prevented from overlapping each other. It can be understood that when the pilot symbols are mapped once every 2K FBMC signals, the other symbols are not transmitted. The moment of the pilot symbol needs to be filled with 0. Referring to FIG. 5, FIG.
  • FIG. 5 is a schematic diagram of an implementation manner of mapping a pilot symbol to a second frequency interval in an FBMC signal according to an embodiment of the present invention, where assuming that a replica filter K of a prototype filter equipped with a transmitter is 4 Then, the pilot symbols are mapped once every 8 time domain symbols, and the values of the pilot symbols remain unchanged in time, and other times are filled with 0s.
  • the pilot subcarrier i is inserted between the data subcarrier m carrying the data and the data subcarrier m+1
  • the pilot subcarrier is inserted between the data subcarrier n carrying the data and the data subcarrier n+1.
  • Carrier j the pilot symbols are mapped once every 8 time domain symbols, and the pilot symbols carried on the i th pilot subcarrier are always and the value of the pilot symbols on the j th pilot subcarrier is always Pj .
  • step A3 the transmitter performs IDFT on the frequency domain signal with the pilot symbol mapped to obtain a time domain signal, and the time domain signal is mapped with a pilot symbol. Further, when the overlap factor of the prototype filter is an integer power of 2, step A3 may specifically include the following steps:
  • the inverse fast Fourier transform (English full name IFFT) is applied to the frequency domain signal with the pilot symbol mapped to obtain the time domain signal with the pilot symbol mapped.
  • IFFT usually refers to the fast Fourier transform with a base of 2, if the value of the overlap factor is not the integer power of 2, it is also possible to add 0 to the frequency domain signal to satisfy the integer power of 2. It is required that IFFT can also be performed in this case.
  • step A3 is performed, and the transmitter performs time domain misalignment superposition on the time domain signal with the pilot symbol mapped to obtain the FBMC signal with the pilot symbol mapped.
  • the signal can be sent by the transmitter to the receiver.
  • step A3 may specifically include the following steps:
  • A31 performing time domain misalignment on the time domain signal according to the offset interval T/2K, where T is the data length of a FBMC time domain signal, and K is an overlap factor of the prototype filter;
  • the transmitter can also flexibly set the value of the misalignment according to the specific application scenario. After all the time domain signals are misaligned, the transmitter superimposes the time domain signals after the misalignment to obtain the FBMC signal.
  • the step 103 generates the FBMC signal with the pilot symbol mapped by using the pilot symbols and the frequency domain signals in the time domain, which may include the following steps:
  • the frequency domain signal has the first frequency between adjacent subcarriers in the same subband.
  • the interval has a second frequency interval between adjacent subcarriers between two adjacent subbands.
  • step B1 generates a FBMC signal from the frequency domain signal, and may include the following steps:
  • the transmitter performs frequency domain filtering on the frequency domain signal to obtain a frequency domain filtered frequency domain signal.
  • the OQAM symbols carried on the multiple sub-bands constitute an FBMC signal, and each FBMC signal includes an OQAM symbol carried on multiple sub-bands.
  • the transmitter performs frequency domain filtering on the frequency domain signal, specifically Implemented by a filter configured in the transmitter.
  • step B11 performs frequency domain filtering on the frequency domain signal, and specifically includes the following steps:
  • the frequency domain signal is convoluted with the frequency domain response of the filter configured in the transmitter to obtain a frequency domain filtered frequency domain signal.
  • step B12 IDF is performed on the frequency domain filtered frequency domain signal to obtain a time domain signal, and the frequency domain signal is converted from the frequency domain to the time domain. It should be noted that, in some embodiments of the present invention, when the value of the overlap factor is an integer power of 2, step B12 enters the frequency domain filtered frequency domain signal.
  • the line IDFT may specifically include the following steps:
  • IFFT is performed on the frequency domain filtered frequency domain signal.
  • IFFT usually refers to the fast Fourier transform with a base of 2, if the value of the overlap factor is not the integer power of 2, it is also possible to add 0 to the frequency domain signal to satisfy the integer power of 2. It is required that IFFT can also be performed in this case.
  • step B13 time domain misalignment is performed on the time domain signal to obtain an FBMC signal, which is a signal in the time domain, including multiple time domain symbols, and the transmitter then performs time domain misalignment superposition on the time domain signal.
  • FBMC signal which can be used to send to the receiver.
  • step B1 generates a FBMC signal from the frequency domain signal, and may include the following steps:
  • B15 Perform multi-phase network filtering on the time domain signal to obtain a filtered time domain signal.
  • B16 Perform time domain misalignment of the time domain signal to obtain the FBMC signal.
  • step B14 the transmitter performs inverse Fourier transform on the frequency domain signal to obtain a time domain signal, and then performs step B15 to perform multiphase network filtering on the time domain signal to obtain a filtered time domain signal, which can be specifically
  • the polyphase filter is used to filter the time domain signal.
  • the time domain data after inverse Fourier transform can be divided into multiple branch time domain signals according to different phases, and the time domain signals on each branch are passed through one.
  • the filter corresponding to its phase is filtered, and then the output results of all the filters are parallel-converted, and finally the filtered time domain signal is obtained.
  • the pilot symbols are first mapped, and mapped to the second frequency interval corresponding to each pilot symbol, to generate a signal mapped on the second frequency interval, wherein the time-domain continuous pilot symbol refers to a single guide.
  • the frequency domain representation of the frequency can be represented by the letter s
  • the signal mapped on the second frequency interval is a time domain representation of a plurality of time-domain continuous pilot symbols mapped at different frequency domain positions, for example 4 ⁇
  • the frequency domain has two pilot symbols 81 and 8 2 respectively mapped into two second frequency intervals, and the frequency points thereof are respectively, and the signal mapped on the second frequency interval can be expressed as
  • step ⁇ 3 After obtaining the signal mapped on the second frequency interval by step ⁇ 2, combining the FBMC signal generated in step B1 and the signal generated in step ⁇ 2 on the second frequency interval, the mapped pilot symbol can be obtained.
  • FBMC signal For step ⁇ 3, after obtaining the signal mapped on the second frequency interval by step ⁇ 2, combining the FBMC signal generated in step B1 and the signal generated in step ⁇ 2 on the second frequency interval, the mapped pilot symbol can be obtained.
  • FBMC signal For step ⁇ 3, after obtaining the signal mapped on the second frequency interval by step ⁇ 2, combining the FBMC signal generated in step B1 and the signal generated in step ⁇ 2 on the second frequency interval, the mapped pilot symbol can be obtained. FBMC signal.
  • the channel in order to estimate the channel, it may be mapped in the FBMC signal.
  • the pilot symbols of the time domain are consecutively mapped.
  • the pilot symbols in the time domain are mapped to the second frequency interval in the FBMC signal, and the pilot symbols can be transmitted together with the FBMC signal, and received by the FBMC signal.
  • the pilot extracts pilot symbols from the FBMC signal for channel estimation. Since the pilot symbol is mapped on the second frequency interval in the FBMC signal, the pilot symbol and the FBMC signal can be isolated by the second frequency interval between adjacent sub-bands, thereby preventing interference of the FBMC signal to the pilot symbol. Even if the adjacent sub-bands experience different channels and the channel changes drastically, the FBMC signal does not interfere with the pilot symbols, so it can be applied to scenes with severe channel changes.
  • the FBMC signal does not interfere with the pilot symbols in the embodiment of the present invention
  • the data subcarrier carrying the FBMC signal is indicated by a broken line
  • the pilot subcarrier carrying the pilot symbol is indicated by a solid line. It can be seen that since the pilot symbols are mapped to the frequency positions between adjacent two sub-bands in the FBMC signal, the frequency domain response of the data subcarrier is 0 or approximately 0 at the pilot subcarrier, so the FBMC signal is not aligned. The frequency symbols cause interference.
  • the spectrum of the OFDM symbol is represented by a SINC function
  • the interference avoidance of the pilot symbol to the FBMC signal is implemented by using a zero point of the SINC function, and the insertion of the pilot subcarrier is performed.
  • IDFT if the pilot subcarrier is viewed alone, this process is similar to OFDM transform.
  • the frequency domain response of the pilot subcarrier appears as a SINC function, and the SINC function is characterized by the center.
  • the response of the location of the data is 1, and its response at the frequency position of the other subcarriers is 0. This is the basic principle that OFDM avoids mutual interference between subcarriers. As shown in FIG.
  • the frequency position of the frequency domain sample of the FBMC signal is exactly the frequency position where the SINC function 0 point of the pilot symbol is located. Therefore, if the pilot subcarrier always appears as a SINC function, Avoid interference from pilot symbols to FBMC signals.
  • the symbol length of the pilot is 2K times the symbol interval of the FBMC signal, where K refers to the overlap factor of the prototype filter provided by the transmitter, so when the receiver receives the FBMC signal.
  • K refers to the overlap factor of the prototype filter provided by the transmitter
  • the pilot symbol and the FBMC signal are out of synchronization, because the pilot symbol takes values in at least one subframe, that is, the value of the pilot symbol is always in the previous value of the repetition, because The pilot symbols are not changed in time, so the time domain symbols formed by the pilot symbols are equivalent to being repeated all the time. As shown in FIG.
  • the first time domain symbol formed by the pilot symbols is represented as S 1 S 2 , ⁇ , S N , S N+1 , -, SKM, pilot symbol composition.
  • the second time domain symbol which is the same as the first time domain symbol, can also be expressed as S 1 S 2 , . ⁇ , S N , S N+1 , ⁇ , SKM, a total of KM samples, then the KM samples are always repeating transmission, K is the overlap factor of the prototype filter provided by the transmitter, and M is the subcarrier of the frequency domain. number. Therefore, taking out KM samples with arbitrary positions as the starting point, the value taken out always corresponds to the cyclic shift of S 1 S 2 , ⁇ , SKM.
  • the data symbol refers to the FBMC signal
  • the cyclic shift of the time domain is equivalent to the phase shift in the frequency domain
  • the KM samples taken at the arbitrary position as the starting point are The performance in the frequency domain is still the SINC function, which is equivalent to multiplying a phase shift factor by the center subcarrier position.
  • the transmitter after the transmitter generates the FBMC signal with the pilot symbol mapped, the transmitter sends the FBMC signal with the pilot symbol mapped to the receiver by using the transmit signal, and the mapping of the FBMC signal sent by the transmitter is guided.
  • the frequency symbol after the receiver receives the FBMC signal, the pilot symbol is parsed from the FBMC signal for signal estimation.
  • the description of the present invention by the above embodiment shows that after the transmitter generates the OQAM symbols included in the at least two subbands, the OQAM symbols on each subband are mapped onto the respective subcarriers to obtain a frequency domain signal, wherein the same subband a first frequency interval between adjacent subcarriers, a second frequency interval between adjacent subcarriers between adjacent two subbands, and a second frequency interval greater than the first frequency interval, and then successively in the time domain
  • the pilot symbol and the frequency domain signal generate an FBMC signal mapped with a pilot symbol, and finally transmit the FBMC signal with the pilot symbol mapped to the receiver, so that the receiver extracts the pilot symbol from the FBMC signal for channel estimation.
  • the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency interval between two adjacent sub-bands, so that the interference of the FBMC signal to the pilot symbols can be avoided, so that the mutual interference of the adjacent sub-bands due to the different channels can be eliminated.
  • the pilot symbols can be applied to the channel estimation of the transmit channel in a scene with severe channel variations.
  • the above embodiment describes a method for transmitting a pilot symbol provided by an embodiment of the present invention from a transmitter side, and then introduces another pilot symbol provided by an embodiment of the present invention from a receiver side.
  • the receiving method as shown in FIG. 6, can mainly include the following steps:
  • Receive an FBMC signal sent by the transmitter where the FBMC signal maps a continual pilot symbol in a time domain, and a first frequency interval between adjacent subcarriers in the same subband of the FBMC signal, and two adjacent sub-FBs of the FBMC signal. There is a second frequency interval between adjacent subcarriers between the bands, and the second frequency interval is greater than the first frequency interval.
  • a communication connection is established between the transmitter and the receiver, and the transmitter transmits the FBMC signal, and the receiver can receive the FBMC signal, and map the time-domain continuous guide in the FBMC signal transmitted by the transmitter.
  • the frequency symbol, and the FBMC signal received by the receiver satisfies the signal characteristics that the transmitter has when generating the FBMC signal.
  • the receiver after the receiver receives the FBMC signal through the transmission channel, the receiver pairs the FBMC signal DFT to obtain the FBMC signal after the DFT.
  • the step 602 performs DFT on the FBMC signal, which may include the following steps:
  • the Fast Fourier Transform (English full name Fast Fourier Transform, FFT for short) is applied to the FBMC signal.
  • the FFT usually refers to the fast Fourier transform with a base of 2, if the value of the overlap factor is not the integer power of 2, if the transmitter adds 0 to the FBMC frequency domain signal to satisfy the integer power of 2.
  • the IFFT is used in the request, and in this case the receiver can also perform the same number of FFTs as the transmitter's IFFT.
  • the receiving method of the pilot symbol provided by the embodiment of the present invention further includes the following steps:
  • step 602 performs DFT on the FBMC signal, which may include the following steps:
  • DFT is performed on the FBMC signal after windowing or filtering.
  • the pilot symbol is mapped in the FBMC signal.
  • the FBMC signal may be windowed or filtered in advance, which may be implemented by a bandpass windowing function and a bandpass filter. Signals other than pilot symbols are suppressed. 603. Extract pilot symbols from a second frequency interval in the FBMC signal after the DFT.
  • DFT is performed on the FBMC signal
  • the conversion of the FBMC signal from the time domain to the frequency domain is completed, and then the receiver follows the position of the second frequency interval of the transmitter mapped pilot symbols from the FBMC after the DFT.
  • a pilot symbol is extracted from the signal.
  • the receiver uses the extracted pilot symbols to perform channel estimation on the FBMC signal and the channel experienced by the pilot symbols.
  • the pilot symbol is mapped to the second frequency interval in the FBMC signal.
  • the second frequency interval includes the guard band interval, which can avoid interference of the FBMC signal to the pilot symbol, and extract the pilot according to the interference-free manner.
  • the symbol is used for channel estimation and can be used for channel estimation accuracy.
  • the receiver extracts pilot symbols from the FBMC signal for channel estimation. Since the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, further, the second frequency interval may further include a guard band interval, and the pilot symbol is mapped to the second frequency in the FBMC signal. Interval, the pilot symbols can be isolated by the second frequency interval between two adjacent sub-bands, so that the interference of the FBMC signal to the pilot symbols can be avoided, so that adjacent sub-bands can be channeled due to different channels. The generated mutual interference is eliminated, so the pilot symbols can be applied to channel estimation of the transmission channel in a scene with severe channel variation. To facilitate a better understanding and implementation of the above solutions of the embodiments of the present invention, the corresponding application scenarios are exemplified below for specific description.
  • embodiments of the present invention may configure a filter that satisfies the following requirements:
  • the prototype filter has a narrow frequency domain transition band, wherein the transition band refers to the spectrum interval from the center of the filter frequency domain response to the frequency domain response close to 0, and the index for judging whether it is close to 0 is Whether the transmission performance is greatly affected, for example, the frequency domain response of less than -30 dB can be considered to be close to 0, because the signal to interference and noise ratio of the wireless communication system is usually below 30 dB.
  • the prototype filter has good real-domain orthogonality under OQAM modulation.
  • the filter can be implemented by some existing filter design and optimization techniques, as shown in FIG. 7-A and FIG. 7-B, which are schematic diagrams showing the time domain and spectral characteristics of the filter provided by the embodiment of the present invention.
  • FIG. 7-A and FIG. 7-B are schematic diagrams showing the time domain and spectral characteristics of the filter provided by the embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a method for transmitting a pilot symbol implemented by a transmitter according to an embodiment of the present invention, which mainly includes the following steps:
  • the aliasing factor of the prototype filter equipped in the transmitter is ⁇ , and the number of subcarriers in the frequency domain is ⁇ .
  • the specific implementation of the transmitter is as follows:
  • the generated OQAM symbol contains L subbands, where L is greater than or equal to 2.
  • a n 2 ..., is used to represent a vector consisting of OQAM symbols on L subbands on the nth FBMC signal, where ⁇ w" J , ] , ⁇ ,
  • n [ 0 , ⁇ -, ⁇ ⁇ ⁇ ⁇ ⁇ ,, ⁇ 2 , «, N £ are positive integers, representing the number of subcarriers in each subband, W '-' + NL two N ⁇ M .
  • n represents the number of the FBMC signal, and N represents the total number of useful subcarriers, which is not numerically greater than the total number of subcarriers M.
  • the role of the subcarrier mapping is to map the OQAM symbols on the L subbands onto the subcarriers (using vector to represent the data on all subcarriers after mapping), assuming that the original interval ⁇ between the two subcarriers is 1 interval. Units, and insert a fractional guard band interval between subbands. In the embodiment shown in Figure 8, the subcarrier mapping occupies all of the subcarriers.
  • mapping rules performed by the transmitter are as follows:
  • the frequency interval between the last subcarrier of the previous subband and the first subcarrier of the latter subband is K+P, where P Is a non-negative integer. That is, if the last subcarrier of the i th subband is mapped to ⁇ ., the 0th subcarrier of the i+1th subband is mapped to ⁇ .
  • FIG. 9 is a schematic diagram of an application scenario in which a guard band interval is inserted between adjacent sub-bands according to an embodiment of the present invention
  • FIG. 9 The subcarrier mapping results of the critical positions of subband i and subband i+1 are given, where, within the same subband, two K-1 zeros are inserted between adjacent subcarriers, and between K+P-1 zeros are inserted between the two subbands.
  • the function of the frequency domain filtering is to filter the frequency of the mapped data block.
  • the implementation of the frequency domain filtering can be obtained by convolving with the filter frequency response fi, that is, where the symbol 0 is a convolutional operator and fi is the frequency response of the prototype filter, which is usually KM in length, but A filter with better frequency domain locality can also cut off its smaller power coefficient to make its length smaller than KM, thus reducing computational complexity.
  • T-point IDFT transformation where T is a value not less than KM, ie ⁇ ⁇ M. If T is greater than KM, you can insert 0 to complement T point on both sides ofenfin, and then do IDFT. Obviously, the IDFT transformed length is T samples.
  • an inverse fast Fourier transform of 2 i.e., an IFFT transform
  • the T point data corresponding to the n+1th real symbol is delayed by T/2K point than the T point data corresponding to the nth real symbol, and all the real symbols are misplaced and then superimposed.
  • the parallel data becomes a serial data stream, and the time-domain misaligned FBMC signal (s(n) shown in Fig. 8) is obtained.
  • the frequency of the pilot subcarrier can be selected as the middle of the sum and / ⁇ 1 , that is, ( ⁇ ' +1 )/2, and the center frequency can be directly generated.
  • ⁇ denotes the second pilot subcarrier
  • p k denotes the pilot symbol carried on the subcarrier
  • the FBMC signal with the pilot symbol is mapped (indicated by), and then Sent to the receiver, from the receiver to the FBMC letter
  • the pilot symbols are extracted from the number for channel estimation.
  • FIG. 10 is a schematic diagram of another method for transmitting a pilot symbol implemented by a transmitter according to an embodiment of the present invention. It can be seen that when K+P is even, the center positions of two adjacent sub-bands fall on a valid frequency sample point, or when the pilot subcarriers are not required to be located at the center of the two sub-bands.
  • the pilot sub-carrier can be inserted in the frequency domain before the IDFT, that is, the pilot symbol is inserted in the frequency domain.
  • the implementation complexity is reduced, and the FBMC signal with the pilot symbols mapped (as shown in FIG. 10) is obtained, and then the FBMC signal is separately subjected to IDFT and time domain misalignment. Therefore, if the execution order in the embodiment of Fig. 8 is S1 ⁇ S2 ⁇ S3 ⁇ S4 ⁇ S5 ⁇ S6, then in the embodiment shown in Fig. 10, the execution order is S1 ⁇ S2 ⁇ S3 ⁇ S6 ⁇ S4 ⁇ S5.
  • FIG. 11 is a schematic diagram of another method for transmitting pilot symbols implemented by a transmitter according to an embodiment of the present invention, respectively generating FBMC signals and time-domain continuous pilot symbols, and adding them.
  • the generation of the FBMC signal can be based on the implementation structure of the polyphase filter.
  • the FBMC signal is generated without mapping data on some preset subcarriers.
  • the number and location of the preset subcarriers usually take into account the overhead, channel model, and channel estimation performance.
  • the pilot pattern 4 that several subcarriers have been selected as idle subcarriers, and no FBMC signals are mapped on the idle subcarriers, and the idle subcarriers can be used as pilot subcarriers for mapping pilot symbols.
  • the frequency symbol generating module generates a time domain continuous pilot symbol on the preset subcarrier, and finally combines the FBMC signal and the pilot symbol, and the transmitter sends the FBMC signal combined with the pilot symbol to the receiver.
  • the prior art generally cancels the interference of the FBMC signal to the pilot symbol by setting the auxiliary pilot, and the method of the auxiliary pilot to cancel the interference is poor in the scene with a severe channel change.
  • the embodiment of the present invention there is no mutual interference between the pilot symbol and the FBMC signal, so there is no need to eliminate the interference by the idea of the auxiliary pilot, which means that the channel variation is severe in the embodiment of the present invention.
  • the scenario has better performance than the auxiliary pilot scheme.
  • a transmitter 1200 may include: a symbol generating module 1201, a symbol mapping module 1202, a signal generating module 1203, and a sending module 1204, where
  • the signal generating module 1201 is configured to generate offset quadrature amplitude modulation OQAM symbols included on at least two subbands;
  • the symbol mapping module 1202 is configured to map the OQAM symbols on each subband to the respective subcarriers to obtain a frequency domain signal, where the adjacent subcarriers in the same subband have a first frequency interval, and the adjacent two a second frequency interval between adjacent subcarriers between the subbands, and the second frequency interval is greater than the first frequency interval;
  • a signal generating module 1203, configured to generate, by using a time domain continuous pilot symbol and the frequency domain signal, a filter bank multicarrier FBMC signal mapped with the pilot symbol, where the pilot symbol is mapped to the second Frequency interval;
  • the transmitting module 1204 is configured to send the FBMC signal to which the pilot symbol is mapped to the receiver, so that the receiver extracts the pilot symbol from the FBMC signal for channel estimation.
  • the symbol mapping module 1202 is specifically configured to map the nth OQAM symbol on the Xth subband to the yth subcarrier;
  • the (n+1)th OQAM symbol on the Xth subband is mapped onto the (y+1)th subcarrier;
  • the first y subcarrier and the (y+1)th subcarrier have a first frequency interval ⁇ , and the X refers to any one of the at least two subbands, and the ⁇ Refers to any one of the OQAM symbols on the Xth subband, the nth OQAM symbol and the (n+1)th OQAM symbol are two adjacent OQAM symbols on the Xth subband, the x , y, n are positive Integer.
  • mapping the nth 0QAM symbol on the Xth subband to the yth subcarrier and mapping the (n+1)th OQAM symbol on the Xth subband to the (y+1)th subcarrier is implemented by:
  • the symbol mapping module 1202 is specifically configured to map the last OQAM symbol on the Xth sub-band to the z-th subcarrier;
  • the first OQAM symbol on (x+1) subbands is mapped onto the (z+1)th subcarrier;
  • the zth subcarrier and the (z+1)th subcarrier have a second frequency interval (m+1) A
  • the ⁇ represents the first frequency interval
  • the m A is a guard band
  • the interval the m is a number greater than 0, and the x and z are positive integers.
  • mapping the last OQAM symbol on the Xth subband to the zth subcarrier and mapping the first OQAM symbol on the (x+1)th subband to the (z+1)th subcarrier And having a second frequency interval (m+ 1) ⁇ between the zth subcarrier and the (z+1)th subcarrier is implemented by:
  • k is the overlap factor of the prototype filter
  • p is the out-of-band rejection factor of the prototype filter
  • the transmitter 1200 further includes:
  • the guard band interval obtaining module 1205 is configured to: before the symbol mapping module 1202 maps the OQAM symbols on each subband to the respective subcarriers, according to the overlap factor and the outband suppression factor of the prototype filter and the first Obtaining the guard band interval by using a frequency interval, where the guard band interval is obtained by: P
  • the G is the guard band interval
  • the overlap factor of the prototype filter the P is an out-of-band rejection factor of the prototype filter
  • the ⁇ is the first frequency interval.
  • the signal generating module 1203 includes:
  • a filter 12031 configured to perform frequency domain filtering on the frequency domain signal
  • a first pilot mapping module 12032 configured to map time-domain contiguous pilot symbols into the frequency domain signal, where the pilot symbols are mapped to a second frequency interval of the frequency domain signal;
  • the first discrete Fourier transform module 12033 is configured to perform an inverse discrete Fourier transform IDFT on the frequency domain signal to which the pilot symbol is mapped, to obtain a time domain signal with the pilot symbol mapped thereon;
  • the first misalignment superposition module 12034 is configured to perform time domain misalignment superposition on the time domain signal to which the pilot symbol is mapped, to obtain an FBMC signal to which the pilot symbol is mapped.
  • the first pilot mapping module 12032 is specifically configured to perform mapping of pilot symbols once every 2K FBMC signal symbol lengths, where K is an overlap factor of the prototype filter.
  • the first pilot mapping module 12032 is specifically configured to map a time domain continuous pilot symbol to a center frequency position of the second frequency interval.
  • the signal generating module 1203 includes:
  • the FBMC generating module 12035 is configured to generate the FBMC signal by using the frequency domain signal
  • the second pilot mapping module 12036 is configured to map the time domain continuous pilot symbols to the corresponding second frequency intervals, and generate the mapping. a signal at two frequency intervals;
  • the signal combining module 12037 is configured to combine the FBMC signal and the signal mapped on the second frequency interval to obtain the FBMC signal with the pilot symbol mapped.
  • the FBMC generating module 12035 may specifically include:
  • a filter 120351 configured to perform frequency domain filtering on the frequency domain signal
  • a second discrete Fourier transform module 120352 configured to perform an inverse discrete Fourier transform (IDFT) on the frequency domain filtered frequency domain signal to obtain a time domain signal;
  • IDFT inverse discrete Fourier transform
  • a second misalignment superposition module 120353 configured to perform time domain misalignment superposition on the time domain signal, To the FBMC signal.
  • the FBMC generating module 12035 may specifically include:
  • An inverse Fourier transform module 120354 configured to perform inverse Fourier transform on the frequency domain signal to obtain a time domain signal
  • a filtering module 120355 configured to perform filtering on the multi-phase network by using the time domain signal to obtain a filtered time domain signal
  • the third misalignment superposition module 120356 is configured to perform time domain misalignment superposition of the time domain signal to obtain the FBMC signal.
  • the pilot symbols remain unchanged over the symbol length of at least two FBMC signals.
  • the description of the present invention by the above embodiment shows that after the transmitter generates the OQAM symbols included in the at least two subbands, the OQAM symbols on each subband are mapped onto the respective subcarriers to obtain a frequency domain signal, wherein the same subband a first frequency interval between adjacent subcarriers, a second frequency interval between adjacent subcarriers between adjacent two subbands, and a second frequency interval greater than the first frequency interval, and then successively in the time domain
  • the pilot symbol and the frequency domain signal generate an FBMC signal mapped with a pilot symbol, and finally transmit the FBMC signal with the pilot symbol mapped to the receiver, so that the receiver extracts the pilot symbol from the FBMC signal for channel estimation.
  • the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency isolation between the adjacent two sub-bands, so that the interference of the FBMC signal to the pilot symbols can be avoided, so that the mutual interference of the adjacent sub-bands due to the different channels can be eliminated.
  • the pilot symbols can be applied to the channel estimation of the transmit channel in a scene with severe channel variations.
  • a receiver 1300 may include: a receiving module 1301, a discrete Fourier transform module 1302, a pilot extracting module 1303, and a channel estimation module 1304, where
  • the receiving module 1301 is configured to receive a filter bank multi-carrier FBMC signal sent by the transmitter, where the FBMC signal maps a pilot symbol that is continuous in a time domain, and the adjacent sub-carrier in the same sub-band of the FBMC signal has a a frequency interval, a second frequency interval between adjacent subcarriers between adjacent two subbands of the FBMC signal, and the second frequency interval is greater than the first frequency Interval
  • a discrete Fourier transform module 1302 configured to perform discrete Fourier transform on the FBMC signal
  • a pilot extraction module 1303, configured to extract a pilot symbol from a second frequency interval in the FBMC signal after the DFT;
  • the channel estimation module 1304 is configured to perform channel estimation using the extracted pilot symbols.
  • the receiver 1300 further includes:
  • the FBMC truncation module 1305 is configured to: after receiving the FBMC signal sent by the transmitter, the receiving module 1301 intercepts the received FBMC signal according to the symbol length of the FBMC signal, to obtain the truncated FBMC signal;
  • the discrete Fourier transform module 1302 is specifically configured to perform DFT on the truncated FBMC signal.
  • the receiver 1300 further includes:
  • the FBMC processing module 1306 is configured to perform windowing processing or filtering processing on the FBMC signal before performing the discrete Fourier transform DFT on the FBMC signal by the discrete Fourier transform module 1302.
  • the discrete Fourier transform module 1302 is specifically configured to perform DFT on the FBMC signal after the windowing process or the filtering process.
  • the receiver extracts pilot symbols from the FBMC signal for channel estimation. Since the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency interval between two adjacent sub-bands, so that interference of the FBMC signals on the pilot symbols can be avoided, so that mutual interference of channels generated by adjacent sub-bands due to different channels can be eliminated. Off, so the pilot symbols can be applied to channel estimation of the transmit channel in a scene with severe channel variations.
  • the embodiment of the present invention further provides a computer storage medium, wherein the computer storage medium stores a program, and the program executes some or all of the steps described in the foregoing method embodiments.
  • FIG. Machine 1400 includes:
  • the input device 1401, the output device 1402, the processor 1403, and the memory 1404 (wherein the number of processors 1403 in the transmitter 1400 may be one or more, and one processor in Fig. 14 is taken as an example).
  • the input device 1401, the output device 1402, the processor 1403, and the memory 1404 may be connected by a bus or other means, wherein the bus connection is taken as an example in FIG.
  • the processor 1403 is configured to perform the following steps:
  • a filter bank multicarrier FBMC signal mapped with the pilot symbols, wherein the pilot symbols are mapped to the second frequency interval;
  • the FBMC signal of the pilot symbol is transmitted to a receiver to cause the receiver to extract the pilot symbols from the FBMC signal for channel estimation.
  • the processor 1403 is specifically configured to perform the following steps:
  • mapping the nth OQAM symbol on the Xth subband to the yth subcarrier and mapping the (n+1)th OQAM symbol on the Xth subband to the (y+1)th sub-carrier is implemented by:
  • the processor 1403 is specifically configured to perform the following steps:
  • mapping the last OQAM symbol on the Xth subband to the zth subcarrier and mapping the first OQAM symbol on the (x+1)th subband to the (z+1)th subcarrier is implemented by:
  • k is the overlap factor of the prototype filter
  • p is the out-of-band rejection factor of the prototype filter
  • the processor 1403 is further configured to perform the following steps: before mapping the OQAM symbols on each subband to the respective subcarriers, according to the overlap factor and the outband suppression factor of the prototype filter. And obtaining, by the first frequency interval, the guard band interval, where the guard band interval is obtained by:
  • the G is the guard band interval
  • the overlap factor of the prototype filter the P is an out-of-band rejection factor of the prototype filter
  • the ⁇ is the first frequency interval.
  • the processor 1403 is specifically configured to perform the following steps: performing frequency domain filtering on the frequency domain signal;
  • IFT inverse discrete Fourier transform
  • the processor 1403 is specifically configured to perform the following steps: mapping the pilot symbols once every 2K symbol lengths of the FBMC signals, where K is an overlap factor of the prototype filters.
  • the processor 1403 is specifically configured to perform the step of: mapping time domain continuous pilot symbols to a center frequency position of the second frequency interval.
  • the processor 1403 is specifically configured to perform the following steps: generating the FBMC signal by using the frequency domain signal;
  • the FBMC signal to which the pilot symbol is mapped is obtained.
  • the processor 1403 is specifically configured to perform the following steps: performing frequency domain filtering on the frequency domain signal;
  • the time domain misalignment is superposed on the time domain signal to obtain the FBMC signal.
  • the processor 1403 is specifically configured to perform the following steps: performing inverse Fourier transform on the frequency domain signal to obtain a time domain signal;
  • the time domain signals are time-domain misaligned to obtain the FBMC signal.
  • the pilot symbols stored by memory 1404 remain unchanged over the symbol length of at least two FBMC signals.
  • the description of the present invention by the above embodiment shows that after the transmitter generates the OQAM symbols included in the at least two subbands, the OQAM symbols on each subband are mapped onto the respective subcarriers to obtain a frequency domain signal, wherein the same subband a first frequency interval between adjacent subcarriers, a second frequency interval between adjacent subcarriers between adjacent two subbands, and a second frequency interval greater than the first frequency interval, and then successively in the time domain
  • the pilot symbol and the frequency domain signal generate an FBMC signal mapped with a pilot symbol, and finally transmit the FBMC signal mapped with the pilot symbol to the receiver for reception
  • the pilot extracts pilot symbols from the FBMC signal for channel estimation.
  • the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency isolation between the adjacent two sub-bands, so that the interference of the FBMC signal to the pilot symbols can be avoided, so that the mutual interference of the adjacent sub-bands due to the different channels can be eliminated.
  • the pilot symbols can be applied to the channel estimation of the transmit channel in a scene with severe channel variations.
  • the receiver 1500 includes:
  • the input device 1501, the output device 1502, the processor 1503, and the memory 1504 (wherein the number of the processors 1503 in the receiver 1500 may be one or more, and one processor in Fig. 15 is taken as an example).
  • the input device 1501, the output device 1502, the processor 1503, and the memory 1504 may be connected by a bus or other means, wherein the bus connection is taken as an example in FIG.
  • the processor 1503 is configured to perform the following steps:
  • a filter bank multi-carrier FBMC signal where the FBMC signal maps a continual pilot symbol, and the FBMC signal has a first frequency interval between adjacent sub-carriers in the same sub-band, a second frequency interval between adjacent subcarriers between adjacent two subbands of the FBMC signal, and the second frequency interval is greater than the first frequency interval;
  • Channel estimation is performed using the extracted pilot symbols.
  • the processor 1503 is further configured to: after receiving the FBMC signal sent by the transmitter, truncating the received FBMC signal according to the symbol length of the FBMC signal, to obtain the truncated FBMC signal;
  • the processor 1503 is specifically configured to perform the following steps:
  • DFT is performed on the truncated FBMC signal.
  • the processor 1503 is further configured to: perform a windowing process or a filtering process on the FBMC signal before performing the discrete Fourier transform DFT on the FBMC signal;
  • the processor 1503 is specifically configured to perform the following steps:
  • the receiver extracts pilot symbols from the FBMC signal for channel estimation. Since the transmitter forms a second frequency interval between adjacent subcarriers of two adjacent subbands, the second frequency interval is greater than the first frequency interval, and the pilot symbols are mapped on the second frequency interval in the FBMC signal, so The pilot symbols are isolated by the second frequency interval between two adjacent sub-bands, so that interference of the FBMC signals on the pilot symbols can be avoided, so that mutual interference of channels generated by adjacent sub-bands due to different channels can be eliminated. Off, so the pilot symbols can be applied to channel estimation of the transmit channel in a scene with severe channel variations.
  • the device embodiments described above are merely illustrative, and the components may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment. Further, in the drawings of the apparatus embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection therebetween, and specifically, one or more communication buses or signal lines can be realized. Those of ordinary skill in the art can understand and implement without any creative effort.
  • the present invention can be implemented by means of software plus necessary general hardware, and of course, through dedicated hardware, including an application specific integrated circuit, a dedicated CPU, a dedicated memory, Special components and so on.
  • functions performed by computer programs can be easily implemented with the corresponding hardware.
  • the specific hardware structure used to implement the same function can be various, such as analog circuits, digital circuits, or dedicated circuits. Circuits, etc.
  • software program implementation is a better implementation in more cases.
  • the technical solution of the present invention which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a readable storage medium, such as a floppy disk of a computer.
  • a readable storage medium such as a floppy disk of a computer.
  • U disk mobile hard disk, read only memory (ROM, ead-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., including a number of instructions to make a computer device (may be a personal computer, server, or network device, etc.) performs the methods described in various embodiments of the present invention.

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  • Computer Networks & Wireless Communication (AREA)
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Abstract

L'invention concerne un procédé de transmission de symbole de fréquence pilote, un procédé de de réception et un émetteur, et un récepteur, pouvant être utilisés pour l'estimation de canal d'un canal qui change considérablement. Le procédé de transmission de symbole de fréquence pilote comprend les étapes consistant : à générer des symboles de modulation d'amplitude en quadrature décalé (MAQD) compris dans au moins deux sous-bandes ; à mapper respectivement les symboles MAQD dans chaque sous-bande à des sous-porteuses individuelles, et à obtenir des signaux de domaine de fréquence, un premier intervalle de fréquence étant prévu entre des sous-porteuses voisines dans la même sous-bande, un second intervalle de fréquence étant prévu entre des sous-porteuses voisines entre deux sous-bandes voisines, et le second intervalle de fréquences étant plus grand que le premier intervalle de fréquences ; en l'utilisation des symboles de fréquence pilote ayant des domaines temporels continus et de signaux de domaine de fréquence afin de générer un signal de multi-porteuse à base de banc de filtre (FBMC) mappé aux symboles de fréquence pilote, les symboles de fréquence pilote étant mappés au second intervalle de fréquences; et en la transmission à un récepteur le signal FBMC mappé aux symboles de fréquence pilote, de sorte que le récepteur extrait les symboles de fréquence pilote à partir du signal FBMC pour l'estimation de canal.
PCT/CN2014/084290 2014-08-13 2014-08-13 Procédé de transmission de symbole de fréquence pilote, procédé de réception, et émetteur et récepteur WO2016023195A1 (fr)

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