CN107204947B - FTN pre-equalization transmission method, transmitter, receiver and system - Google Patents

FTN pre-equalization transmission method, transmitter, receiver and system Download PDF

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CN107204947B
CN107204947B CN201710476283.0A CN201710476283A CN107204947B CN 107204947 B CN107204947 B CN 107204947B CN 201710476283 A CN201710476283 A CN 201710476283A CN 107204947 B CN107204947 B CN 107204947B
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CN107204947A (en
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李明齐
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Shanghai Advanced Research Institute of CAS
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03343—Arrangements at the transmitter end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03012—Arrangements for removing intersymbol interference operating in the time domain
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03828—Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties

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Abstract

The invention provides a super-Nyquist (FTN) pre-equalization transmission method, a transmitter, a receiver and a system, wherein a code element symbol to be transmitted is divided into blocks at a transmitting end, each symbol block is pre-equalized to eliminate self-intersymbol interference (ISI) influence caused by subsequent super-Nyquist rate shaping filtering in advance, then the pre-equalized symbol blocks are shaped and filtered according to the super-Nyquist rate, then block symbols which can keep the super-Nyquist rate and circulate from head to tail are formed through circulating superposition operation, and finally a protection interval is added to the symbol blocks to form transmitted baseband symbols. At the receiving end, the ISI caused by the multipath channel is only needed to be eliminated through the guard interval, and the self-ISI influence caused by the transmission at the faster-than-Nyquist rate is not needed to be considered, so that the effect of reducing the complexity of the receiving end is achieved.

Description

FTN pre-equalization transmission method, transmitter, receiver and system
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a FTN pre-equalization transmission method, a transmitter, a receiver, and a system.
Background
With the explosive growth of wireless devices in recent years, and particularly the rapid popularization of intelligent devices capable of transmitting high-speed multimedia streams, the wireless data traffic volume shows an exponential growth trend. Under the realistic dilemma that the total amount of spectrum resources is limited, finding a transmission technology with higher spectrum efficiency is a crucial link in the design of a wireless communication system for the future. One potential technique is Faster than Nyquist transmission (FTN), which allows data transmission at a code rate higher than the Nyquist rate over the same bandwidth to improve the band utilization, thus leading to a hot research trend.
The nyquist criterion requires that signals be orthogonal to each other to avoid degradation of decision accuracy at the receiving end due to intersymbol interference (ISI), and then the trade-off for quality of service is at the expense of spectral efficiency. FTN achieves higher data transmission rates by introducing non-orthogonal signals transmitted from ISI, but after the FTN concept was proposed by Mazo in the last 70 th century, the main reason that conventional communication system design still obeyed the nyquist first criterion was that hardware circuitry could not implement the high complexity algorithms required by the receiving end to remove ISI. Thanks to the rapid development of semiconductor and integrated circuit technologies, hardware circuits are implementing algorithms of higher complexity, and research on FTNs has become a hot spot in recent years.
Currently, research on FTN transmission techniques is mainly limited to simple binary modulation. Although the FTN transmission technique has proven its advantages in non-binary and high-order modulation, the simulation assumes that the channel is an additive white gaussian noise channel, and does not consider the influence of channel fading, and the practicability is still limited. In the design of a multi-carrier FTN transceiver based on Spectral Efficiency Frequency Division Multiplexing (SEFDM), the peak-to-average ratio is too high, which results in waste of transmission energy. In addition, in order to eliminate the inter-symbol crosstalk existing in the received signal, in terms of Detection algorithm, the Maximum Likelihood Sequence Detection (MLSD) algorithm is adopted to obtain the best performance, but the implementation complexity is too high to be applied in practice, and if the received symbol is regarded as the result after convolutional coding, the Viterbi algorithm or the BCJR algorithm can be used for Detection, but the complexity of the two algorithms is greatly improved due to the increase of the number of states caused by the shortening of the inter-symbol interval. In addition, due to the introduction of ISI, the super-nyquist system increases the implementation complexity over the nyquist system in terms of synchronization, channel estimation, equalization, and the like.
In summary, in view of the problems existing in the modulation scheme, the applicable channel model, and the complexity of the ISI cancellation algorithm in the conventional FTN transmission technology, how to reduce the overall implementation complexity of the super-nyquist transmission system applicable to the multipath fading channel is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention provides an FTN pre-equalization transmission method, a transmitter, a receiver and a system, which are used to solve the problem of high complexity of implementing super-nyquist transmission in the prior art.
To achieve the above and other related objects, according to a first aspect of the present invention, an embodiment of the present invention provides an FTN pre-equalization transmission method applied to an FTN pre-equalization transmitter, the method including:
dividing the modulation symbol sequence into a plurality of symbol data blocks;
generating a pre-equalization coefficient corresponding to each symbol data block;
according to the pre-equalization coefficient, pre-equalizing the corresponding symbol data block to obtain a pre-equalized signal sequence;
respectively carrying out super-Nyquist shaping filtering on the pre-equalized signal sequence by using a shaping filter to obtain a filtering signal sequence;
performing head-to-tail cyclic superposition on the filtering signal sequence to obtain a cyclic signal sequence;
and adding a guard interval to the circulating signal sequence to obtain an output signal sequence, and sending the output signal sequence to the FTN pre-equalization receiver.
Optionally, wherein the plurality of symbol data blocks are all the same length.
Optionally, the generating pre-equalization coefficients comprises generating the pre-equalization coefficients through a cyclic autocorrelation operation according to discrete impulse responses of shaping filters corresponding to the types and the displacement of the super-nyquist shaping filter; the length of the pre-equalization coefficients is equal to the length of the symbol data block.
Optionally, the pre-equalization includes frequency domain equalization or time domain equalization, and the frequency domain equalization is performed on the symbol data block, including calculating a vector division operation result of a discrete fourier transform of the symbol data block and a discrete fourier transform of a pre-equalization coefficient; performing inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence;
performing time domain equalization on the symbol data block, wherein the time domain equalization comprises calculating the reciprocal of the discrete Fourier transform of the pre-equalization coefficient in an off-line manner and then taking the inverse discrete Fourier transform of the pre-equalization coefficient; and performing cyclic convolution operation on the inverse transformation output result and the symbol data block to obtain a pre-equalization signal sequence.
Optionally, the upsampling rate of the discrete impulse response of the shaping filter is greater than the amount of the nyquist shaping filter displacement.
Optionally, the shaping filter comprises any one of a root raised cosine filter, a gaussian filter, and an isotropic orthogonal transform algorithm filter.
Optionally, performing head-to-tail cyclic superposition on the filtered signal sequence to obtain a cyclic signal sequence, including:
when t is more than or equal to 0 and less than or equal to P-NFTNAt time-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence;
when P-N is presentFTNThe t is more than or equal to Q-1, and the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence;
wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
Optionally, the length of the cyclic signal sequence is equal to the product of the length of the symbol data block and the displacement of the faster-than-nyquist shaping filter, and the length of the cyclic signal sequence is greater than or equal to the length of the discrete impulse response of the shaping filter.
Optionally, adding a guard interval to the cyclic signal sequence to obtain an output signal sequence, including:
and adding the guard interval at the head or the tail of the cyclic signal sequence, wherein the length of the guard interval is greater than or equal to the maximum time delay spread length of the channel.
Optionally, when the guard interval is added to the head of the cyclic signal sequence, a data block symbol corresponding to the length of the guard interval at the tail of the cyclic signal sequence is copied and added to the head of the cyclic signal sequence.
According to a second aspect of the present invention, an embodiment of the present invention provides an FTN pre-equalization transmission method applied to an FTN pre-equalization receiver, including the following steps:
receiving an output signal sequence sent by an FTN pre-equalization transmitter, and removing a guard interval in the output signal sequence to obtain an input signal sequence;
performing channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence;
and performing circular matching filtering on the channel equalization output signal sequence to obtain a circular matching signal sequence.
Optionally, receiving an output signal sequence sent by the FTN pre-equalization transmitter, and removing a guard interval in the output signal sequence to obtain an input signal sequence, where the method includes:
obtaining protection interval configuration information sent by an FTN pre-equilibrium transmitter, wherein the protection interval configuration information at least carries the setting position and the length of the protection interval;
and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
Optionally, when the equalization operation includes a time domain equalization operation or a frequency domain equalization operation, performing a channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence, including:
when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, performing frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence; alternatively, the first and second electrodes may be,
and when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
Optionally, performing cyclic matching filtering on the channel equalization output signal sequence to obtain a cyclic matching signal sequence, including:
acquiring configuration information of a shaping filter sent by an FTN pre-equalization transmitter, wherein the configuration information of the shaping filter at least carries the type of the shaping filter used by the FTN pre-equalization transmitter, the displacement of the super-Nyquist shaping filter and the length of a symbol data block;
according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence;
the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
According to a third aspect of the present invention, an embodiment of the present invention provides an FTN pre-equalization transmitter, including:
a data block dividing module for dividing the modulation symbol sequence into a plurality of symbol data blocks;
the pre-equalization coefficient generating module is used for generating a pre-equalization coefficient corresponding to each symbol data block;
the pre-equalization module is used for pre-equalizing the corresponding symbol data block according to the pre-equalization coefficient to obtain a pre-equalization signal sequence;
the shaping filtering module is used for performing super-Nyquist shaping filtering on the pre-equalized signal sequence by using a shaping filter to obtain a filtering signal sequence;
the cyclic blocking module is used for performing head-to-tail cyclic superposition on the filtering signal sequence to obtain a cyclic signal sequence;
and the guard interval adding module is used for adding a guard interval on the circulating signal sequence to obtain an output signal sequence and sending the output signal sequence to the FTN pre-equalization receiver.
Optionally, the lengths of the plurality of symbol data blocks obtained by dividing by the data block dividing module are all the same.
Optionally, the pre-equalization coefficient generating module is configured to generate the pre-equalization coefficient through a cyclic autocorrelation operation according to a discrete impulse response of the shaping filter corresponding to the type and the displacement of the super-nyquist shaping filter; the length of the pre-equalization coefficients is equal to the length of the symbol data block.
Optionally, the pre-equalization module is configured to,
performing frequency domain equalization on the symbol data block, wherein the frequency domain equalization comprises calculating a vector division operation result of discrete Fourier transform of the symbol data block and discrete Fourier transform of a pre-equalization coefficient; performing inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence;
performing time domain equalization on the symbol data block, wherein the time domain equalization comprises calculating the reciprocal of the discrete Fourier transform of the pre-equalization coefficient in an off-line manner and then taking the inverse discrete Fourier transform of the pre-equalization coefficient; and performing cyclic convolution operation on the inverse transformation output result and the symbol data block to obtain a pre-equalization signal sequence.
Optionally, the up-sampling rate of the shaping filter is greater than the amount of shift of the super-nyquist shaping filter.
Optionally, the shaping filter comprises any one of a root raised cosine filter, a gaussian filter, and an isotropic orthogonal transform algorithm filter.
Optionally, the loop blocking module is configured to,
when t is more than or equal to 0 and less than or equal to P-NFTNAt time-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence;
when P-N is presentFTNThe t is more than or equal to Q-1, and the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence;
wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
Optionally, the length of the cyclic signal sequence is equal to the product of the length of the symbol data block and the displacement of the faster-than-nyquist shaping filter, and the length of the cyclic signal sequence is greater than or equal to the length of the discrete impulse response of the shaping filter.
Optionally, the guard interval adding module is configured to add the guard interval at the head or the tail of the cyclic signal sequence, and a length of the guard interval is greater than or equal to a maximum delay spread length of a channel.
Optionally, the guard interval adding module is configured to copy and add a data block symbol corresponding to the length of a guard interval at the tail of the cyclic signal sequence to the head of the cyclic signal sequence when the guard interval is added at the head of the cyclic signal sequence.
According to a fourth aspect of the present invention, an embodiment of the present invention provides an FTN pre-equalization receiver, including:
the protection interval removing module is used for receiving an output signal sequence sent by the FTN pre-equalization transmitter and removing a protection interval in the output signal sequence to obtain an input signal sequence;
the channel equalization module is used for carrying out channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence;
and the circulating matching filtering module is used for performing circulating matching filtering on the channel equalization output signal sequence to obtain a circulating matching signal sequence.
Optionally, the guard interval removal module is configured to,
obtaining protection interval configuration information sent by an FTN pre-equilibrium transmitter, wherein the protection interval configuration information at least carries the setting position and the length of the protection interval;
and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
Optionally, the channel equalization module is configured to,
when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, performing frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence; alternatively, the first and second electrodes may be,
when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence
Optionally, the loop-matched filtering module is adapted to,
acquiring configuration information of a shaping filter sent by an FTN pre-equalization transmitter, wherein the configuration information of the shaping filter at least carries the type of the shaping filter used by the FTN pre-equalization transmitter, the displacement of the super-Nyquist shaping filter and the length of a symbol data block;
according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence;
the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
According to a fifth aspect of the present invention, the present invention provides an FTN pre-equalization transmission system, which includes the FTN pre-equalization transmitter described in the above embodiment, and the FTN pre-equalization receiver described in the above embodiment.
As described above, the transmission method, transmitter, receiver and system of the super-nyquist rate block according to the present invention have the following advantages: the method comprises the steps of firstly blocking code element symbols to be transmitted at a transmitting end, pre-equalizing each symbol block to eliminate self-ISI (inter-symbol interference) caused by subsequent super-Nyquist rate shaping filtering in advance, then shaping filtering the pre-equalized symbol blocks according to the super-Nyquist rate, then forming block symbols which can keep the super-Nyquist rate and circulate from head to tail through cyclic superposition operation, and finally adding a guard interval to the symbol blocks to form transmitted baseband symbols. At the receiving end, the ISI caused by the multipath channel is only needed to be eliminated through the guard interval, and the self-ISI influence caused by the transmission at the faster-than-Nyquist rate is not needed to be considered, so that the effect of reducing the complexity of the receiving end is achieved.
Drawings
Fig. 1 is a flowchart illustrating a transmitter-side FTN pre-equalization transmission method according to an embodiment of the present invention.
Fig. 2 is a schematic flow chart of a cyclic stacking method according to an embodiment of the present invention.
Fig. 3 is a flowchart illustrating a receiver-side FTN pre-equalization transmission method according to an embodiment of the present invention.
Fig. 4 is a flowchart illustrating a method for removing a guard interval according to an embodiment of the present invention.
Fig. 5 is a flowchart illustrating a channel equalization method according to an embodiment of the present invention.
Fig. 6 is a flowchart illustrating a loop matched filtering method according to an embodiment of the present invention.
Fig. 7 is a schematic structural diagram of an FTN pre-equalization transmitter according to an embodiment of the present invention.
Fig. 8 is a schematic structural diagram of an FTN pre-equalization receiver according to an embodiment of the present invention.
Fig. 9 is a schematic structural diagram of an FTN transmission system according to an embodiment of the present invention.
Fig. 10 is a graph illustrating frequency efficiency results provided by an embodiment of the present invention.
Fig. 11 is a schematic diagram illustrating a received reconstructed snr result according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Please refer to fig. 1 to 11. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
Referring to fig. 1, a schematic flow chart of a transmitter-side FTN pre-equalization transmission method according to an embodiment of the present invention is shown, and as shown in fig. 1, an embodiment of the present invention shows a process of implementing the transmission method by an FTN pre-equalization transmitter:
step S101: the modulation symbol sequence is divided into a plurality of symbol data blocks.
In an exemplary embodiment, the modulation symbol sequence may be represented as { x (n) }, n ═ 0,1,2. In the embodiment of the present invention, the modulation symbol sequence is divided into a plurality of symbol data blocks, and the length of each symbol data block may be equal to D, so that the plurality of symbol data blocks can form a symbol data block sequence. A symbol data block may be exemplarily represented as { a (D) }, D ═ 0,1,2. Since the transmitter operates identically and independently for each symbol data block, the following steps will be described in detail by taking the processing procedure of one symbol data block as an example.
Of course, it should be noted that the lengths of the symbol data blocks may also be different, and the segmentation rule of the symbol data block may be preset between the FTN pre-equalization receiver and the FTN pre-equalization transmitter, or in the communication process between the FTN pre-equalization receiver and the FTN pre-equalization transmitter, the FTN pre-equalization transmitter may send the segmentation rule of the symbol data block to the FTN pre-equalization receiver, so that the FTN pre-equalization receiver and the FTN pre-equalization transmitter have a uniform symbol data block.
Step S102: and generating a pre-equalization coefficient corresponding to each symbol data block.
The pre-equalization coefficients { cf (D) }, D ═ 0., D-1} are used for pre-equalization from inter-symbol interference, and the pre-equalization coefficients can be generated by a cyclic autocorrelation operation according to the discrete impulse response of the shaping filter and the displacement of the super-nyquist shaping filter, and the specific formula is as follows:
Figure BDA0001328334570000071
Figure BDA0001328334570000081
wherein cf (d) is a pre-equalization coefficient, fp(t) is the discrete impulse response of the shaping filter, L is the discrete impulse response f of the shaping filterp(t) length, Q is the length of the predetermined output signal sequence, NFTNFor the super-Nyquist shaping filter shift, ()*Expression taking conjugate operation, ()QRepresenting a modulo Q operation. The length of the pre-equalization coefficients is equal to the length D of the symbol data block.
Step S103: and pre-equalizing the corresponding symbol data block according to the pre-equalization coefficient to obtain a pre-equalized signal sequence.
According to step S102, a pre-equalization coefficient { cf (D), where D is 0,.. and D-1}, the symbol data block { a (D), where D is 0,1,2.. D-1} is pre-equalized to obtain a pre-equalized signal sequence { q (D), where D is 0,1,2.. and D-1}, where the pre-equalization may include time domain equalization or frequency domain equalization.
When the symbol data block is subjected to frequency domain equalization, the frequency domain equalization comprises calculating a vector division operation result of discrete Fourier transform of the symbol data block and discrete Fourier transform of a pre-equalization coefficient; and carrying out inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence.
The equalized output signal sequence { q (D) }, D ═ 0,1,2.. D-1} can be calculated by the following formula:
q(d)＝IDFTD{DFTD{a(d)}·/DFTD{cf(d)}}，
wherein q (d) is the equalized output signal sequence, a (d) is the symbol data block, cf (d) is the pre-equalization coefficient, DFTD{ } discrete Fourier transform operation of D points, IDFTD{ } is the inverse discrete Fourier transform operation of D points,/is the vector division operation.
When the symbol data block is subjected to time domain equalization, the time domain equalization comprises the steps of calculating the reciprocal of the discrete Fourier transform of the pre-equalization coefficient in an off-line mode and then taking the inverse discrete Fourier transform of the pre-equalization coefficient; and performing cyclic convolution operation on the inverse transformation output result and the symbol data block to obtain a pre-equalization signal sequence.
In the case of pre-equalization being time-domain equalization, the equalization output signal sequence { q (D) }, D ═ 0,1,2, … D-1, may be calculated by the following formula:
Figure BDA0001328334570000082
wherein the content of the first and second substances,
Figure BDA0001328334570000083
for the cyclic convolution operation, q (d) is the equalized output signal sequence, a (d) is the symbol data block, cf (d) is the pre-equalization coefficient, DFTDIs a discrete Fourier of D pointOperation of the interior transform, IDFTD{ } is the inverse discrete Fourier transform operation of D points,/is the vector division operation.
Note that the length of the equalized output signal sequence q (D) is the same as the length D of the symbol data block.
Step S104: and respectively carrying out super-Nyquist shaping filtering on the pre-equalized signal sequence by using a shaping filter to obtain a filtering signal sequence.
And performing super-nyquist shaping filtering on the equalized output signal sequence { q (D) obtained in step S103, wherein D is 0,1,2.. D-1} to obtain a filtered signal sequence { g (t), and t is 0,1,2.. P-1 }.
In the implementation of the present invention, the shaping filter may adopt a real or complex filter, and preferably selects any one of a root-raised cosine filter, a gaussian filter and an Isotropic Orthogonal Transform (IOTA) filter.
In a specific implementation, the equalization output signal sequence { q (D) }, D ═ 0,1,2.. D-1} is subjected to super-nyquist shaping filtering, the output filtered signal sequence is { g (t) }, t ═ 0,1,2.. P-1}, and g (t) can be expressed by the following formula:
Figure BDA0001328334570000091
where D is the length of the symbol data block, fp(t) discrete impulse response of the shaping filter, NFTNP is the length of the output filtered signal sequence for the amount of the Nyquist shaped filter shift.
For faster than Nyquist rate transmission, in an exemplary embodiment, the discrete impulse response f of the shaping filterp(t) the upsampling rate N is greater than the Nyquist shaping filter displacement NFTNI.e. N>NFTN. Wherein the Nyquist shaping filtering displacement N FTN16, 17, 18, 19, etc., and the up-sampling rate N may be set to 20, etc., of course, the up-sampling rate N and the amount of shift N of the super-nyquist shaping filter are set toFTNThe setting of (1) is only an exemplary embodiment, and any other values may be set in the specific implementation, and are not limited in the embodiment of the present invention.
The length P of the output filtered signal sequence, the length D of the symbol data block, and the Nyquist filter shift amount NFTNAnd the discrete impulse response f of the shaping filterp(t) a length L having the following relationship:
P＝D×NFTN+L
step S105: and circularly superposing the filtered signal sequences from beginning to end to obtain a circular signal sequence.
And continuing to perform ending cyclic superposition on the filtered signal sequence { g (t), where t is 0,1,2.. P-1} obtained in step S104, so as to obtain a cyclic signal sequence, which is denoted by { b (t), and t is 0,1,2.. Q-1}, where Q is the length of the cyclic signal sequence.
Referring to fig. 2, a schematic flow chart of a cyclic stacking method according to an embodiment of the present invention is shown in fig. 2, where the method includes the following steps:
step S1051: when t is more than or equal to 0 and less than or equal to P-NFTNAnd at-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence.
Step S1052: when P-N is presentFTNWhen t is less than or equal to Q-1, the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence; wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
Thus, a specific formula for generating the cyclic signal sequence can be expressed as follows:
Figure BDA0001328334570000101
furthermore, in the embodiment of the present invention, the length Q of the cyclic signal sequence is equal to the length D of the symbol data block and the nyquist shaping filtering displacement NFTNAnd the length Q of the cyclic signal sequence is greater than or equal to the length L of the discrete impulse response of the shaping filter. Specifically, Q ═ D × NFTNAnd L is less than or equal to Q<P。
Step S106: and adding a guard interval to the circulating signal sequence to obtain an output signal sequence, and sending the output signal sequence to the FTN pre-equalization receiver.
To reduce inter-channel interference, in an exemplary embodiment, a guard interval may be added at the head or tail of the cyclic signal sequence b (t); moreover, the length of the guard interval is preferably greater than or equal to the maximum delay spread length of the channel.
In a specific embodiment, the guard interval may be added to the header of the cyclic signal sequence by means of a cyclic prefix: and copying and adding a data block symbol which is positioned at the tail part of the cyclic signal sequence and corresponds to the length of the guard interval to the head part of the cyclic signal sequence, thereby forming an output signal sequence of the prefix to be circulated.
By adding the guard interval, the cyclic signal sequence { b (t), t 0,1,2.. Q-1} is transformed into a complete output signal sequence { s (t), t 0,1,2.. Q + C-1}, where C is the length of the guard interval.
The generated output signal sequence is sent to the FTN pre-equalization receiver or sent to the surrounding environment in a broadcast manner, so that the FTN pre-equalization receiver can receive the output signal sequence. It should be noted that, in specific implementation, the sending process of the output signal sequence may further include steps of channel coding, digital modulation, radio frequency conversion, transmission, and the like, and details are not described in the implementation of the present invention.
Referring to fig. 3, a schematic flow chart of a receiver-side FTN pre-equalization transmission method according to an embodiment of the present invention is shown, and as shown in fig. 3, an embodiment of the present invention shows a process of implementing the transmission method by an FTN pre-equalization receiver:
step S201: and receiving an output signal sequence sent by the FTN pre-equalization transmitter, and removing a guard interval in the output signal sequence to obtain an input signal sequence.
It should be noted that, taking a digital communication system as an example, the receiver may further need to perform steps of radio frequency conversion, synchronization, channel estimation, digital demodulation, and the like when receiving a signal, and details are not repeated in the implementation of the present invention. In the embodiment of the invention, a transmission method of a super-nyquist rate block implemented on the side of an FTN pre-equalization transmitter is described in detail by taking a received output signal sequence { r (t) } 0, 1., Q + C-1} sent by the FTN pre-equalization transmitter as an example; where Q is the length of the output signal sequence and C is the length of the guard interval.
The FTN pre-equalization receiver discards C sample values in the data block as guard intervals according to the FTN pre-equalization transmitter guard interval addition rule, thereby forming an input signal sequence { y (t) of length Q, t ═ 0,1,2.
In the first implementation case, an addition rule of the guard interval may be preset, where the addition rule specifies parameters such as an addition position of the guard interval and a length of the guard interval; therefore, the FTN pre-equalization transmitter can increase the guard interval according to the preset adding rule and send an output signal sequence to the FTN pre-equalization receiver, and the FTN pre-equalization receiver removes the guard interval increased by the FTN pre-equalization transmitter according to the preset adding rule so as to obtain an input signal sequence.
In a second implementation case, since the FTN pre-equalization transmitter may need to change the rule of adding the guard interval, in order to improve the flexibility and efficiency of guard interval removal, referring to fig. 4, a flowchart of a method for removing the guard interval provided by an embodiment of the present invention is shown in fig. 4, where the method includes:
step S2011: and obtaining the configuration information of the guard interval sent by the FTN pre-equilibrium transmitter, wherein the configuration information of the guard interval at least carries the setting position and the length of the guard interval.
When the FTN pre-equalization transmitter sends the output signal sequence, the FTN pre-equalization transmitter can also send out guard interval configuration information; the guard interval configuration information may be integrated into a field in the output signal sequence, or send implementation guard interval configuration information to the FTN pre-equalization receiver in the form of an independent field, which is not limited in the embodiment of the present invention. And, the guard interval configuration information carries a setting position of a guard interval added by the FTN pre-equalization transmitter and a length of the guard interval. Further, the FTN pre-equalization receiver acquires the guard interval configuration information sent by the FTN pre-equalization transmitter.
Step S2012: and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
And the FTN pre-equalization receiver removes the data symbols in the output signal sequence corresponding to the length from the set position in the output signal sequence according to the set position and the length of the guard interval acquired from the guard interval configuration information, thereby obtaining the input signal sequence with the guard interval removed.
Step S202: and carrying out channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
According to the input signal sequence { y (t), t being 0,1,2,., Q-1} obtained in step S201, the channel equalization operation is performed on the input signal sequence { y (t), t being 0,1,2,., Q-1} so as to obtain a channel equalization output signal sequence { e (t), t being 0,1,2,., Q-1 }. Wherein the channel equalization operation may comprise a time domain equalization operation or a frequency domain equalization operation.
As different channel equalization operations may need to be performed under different implementation conditions, in order to improve the efficiency of the channel equalization operation, referring to fig. 5, a flowchart of a channel equalization method provided in an embodiment of the present invention is shown in fig. 5, where the method includes:
step S2021: and when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, carrying out frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
The bandwidth threshold may be a preset bandwidth threshold, and when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, it indicates that the current signal transmission scene is a broadband; and when the bandwidth of the transmission signal is less than the bandwidth threshold, the current signal transmission scene is indicated to be a narrow band.
For the wideband case, the channel equalization may be frequency domain equalization; further, performing frequency domain equalization operation on the input signal sequence { y (t), t ═ 0,1,2,. and Q-1} to obtain a channel equalization output signal sequence; the process of the frequency domain equalization operation is not described in detail in the embodiment of the present invention.
Step S2022: and when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
When the bandwidth of the transmission signal is smaller than the bandwidth threshold, the current signal transmission scene is indicated to be a narrow band; for the narrowband case, the channel equalization may be time domain equalization; further, performing time domain equalization operation on the input signal sequence { y (t), t ═ 0,1,2,. and Q-1} to obtain a channel equalization output signal sequence; the process of the time domain equalization operation is not described in detail in the embodiment of the present invention.
Therefore, the embodiment of the invention can select different channel balance operation strategies according to the broadband and narrowband scenes, thereby effectively improving the channel balance calculation efficiency.
Step S203: and performing circular matching filtering on the channel equalization output signal sequence to obtain a circular matching signal sequence.
And performing cyclic matching filtering on the channel equalization output signal sequence { e (t) } obtained in the step S202, wherein t is 0,1,2.
In a first implementation case, the FTN pre-equalization transmitter and the FTN pre-equalization receiver may preset the same shaping filter and parameter information such as the length of the symbol data block; thus, the FTN pre-equalization transmitter can generate and send an output signal sequence according to preset parameter information such as the length of a shaping filter and a symbol data block; further, the FTN pre-equalization receiver performs the above steps on the received output signal sequence according to the preset shaping filter and the parameter information such as the length of the symbol data block, and then performs the cyclic matching filtering in this step to obtain a cyclic matching signal sequence.
In a second implementation case, since the FTN pre-equalization transmitter may need to change parameters such as using different shaping filters and configuring different lengths of symbol data blocks, in order to improve flexibility and efficiency of the cyclic matched filtering, referring to fig. 6, a flowchart of a cyclic matched filtering method provided for an embodiment of the present invention is shown in fig. 6, where the method includes:
step S2031: and acquiring configuration information of a shaping filter sent by the FTN pre-equalization transmitter, wherein the configuration information of the shaping filter at least carries the type of the shaping filter used by the FTN pre-equalization transmitter, the displacement of the super-Nyquist shaping filter and the length of the symbol data block.
The FTN pre-equalization transmitter may carry the shaping filter configuration information in a field of the output signal sequence while sending the output signal sequence, or the FTN pre-equalization transmitter may send independent shaping filter configuration information, which is not limited in the embodiment of the present invention. The shaping filter configuration information is received by the FTN pre-equalization receiver, and the shaping filter configuration information at least carries the type of shaping filter used by the FTN pre-equalization transmitter, the amount of displacement of the Nyquist shaping filter, and the length of the symbol data block.
Step S2032: according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence; wherein the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
And the FTN pre-equalization receiver further selects a forming filter corresponding to the type, and performs circulating matched filtering on the channel equalization output signal sequence to obtain a circulating matched signal sequence.
The cyclic matching signal sequence o (d) can be calculated by the following formula:
Figure BDA0001328334570000131
Figure BDA0001328334570000132
wherein f isp(t) is the discrete impulse response of the shaping filter, L is the discrete impulse response f of the shaping filterp(t) length, Q is the length of the cyclic match signal sequence, NFTNFor the super-Nyquist shaping filter shift, ()*Represents a conjugate operation, ()QRepresenting a modulo Q operation.
The generated cyclic matching signal sequence may be denoted as { o (D) }, D ═ 0,1,2.., D-1}, wherein the length of the cyclic matching signal sequence is the same as the length D of the symbol data block.
Corresponding to the embodiment of the FTN pre-equalization transmission method provided by the embodiment of the present invention, the embodiment of the present invention also provides an embodiment of an FTN transmission apparatus.
Referring to fig. 7, a schematic structural diagram of an FTN pre-equalization transmitter according to an embodiment of the present invention is shown in fig. 7, where the transmitter includes:
a data block dividing module 11, configured to divide the modulation symbol sequence into a plurality of symbol data blocks;
a pre-equalization coefficient generating module 12, configured to generate a pre-equalization coefficient corresponding to each symbol data block;
a pre-equalization module 13, configured to pre-equalize corresponding symbol data blocks according to the pre-equalization coefficients to obtain pre-equalized signal sequences;
a shaping and filtering module 14, configured to perform super-nyquist shaping and filtering on the pre-equalized signal sequence by using a shaping filter, so as to obtain a filtered signal sequence;
a cyclic blocking module 15, configured to perform head-to-tail cyclic superposition on the filtered signal sequence to obtain a cyclic signal sequence;
and a guard interval adding module 16, configured to add a guard interval to the cyclic signal sequence to obtain an output signal sequence, and send the output signal sequence to the FTN pre-equalization receiver.
In a specific implementation, the lengths of the plurality of symbol data blocks obtained by dividing by the data block dividing module 11 are all the same.
Optionally, the pre-equalization module 13 is configured to perform frequency domain equalization on the symbol data block, and includes calculating a result of vector division operation of discrete fourier transform of the symbol data block and discrete fourier transform of a pre-equalization coefficient; performing inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence; performing time domain equalization on the symbol data block, including calculating a discrete Fourier transform result of a pre-equalization coefficient; and performing cyclic convolution operation on the discrete Fourier transform of the symbol data block and the equalization coefficient to obtain a pre-equalization signal sequence.
Optionally, the up-sampling rate of the shaping filter is greater than the amount of shift of the super-nyquist shaping filter.
Optionally, the shaping filter comprises any one of a root raised cosine filter, a gaussian filter, and an Isotropic Orthogonal Transform Algorithm (IOTA) filter.
Optionally, the loop blocking module is configured to,
when t is more than or equal to 0 and less than or equal to P-NFTNAt time-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence;
when P-N is presentFTNThe t is more than or equal to Q-1, and the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence;
wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
Optionally, the length of the cyclic signal sequence is equal to the product of the length of the symbol data block and the displacement of the faster-than-nyquist shaping filter, and the length of the cyclic signal sequence is greater than or equal to the response length of the shaping filter.
Optionally, the guard interval adding module 16 is configured to add the guard interval at the head or the tail of the cyclic signal sequence, and a length of the guard interval is greater than or equal to a maximum delay spread length of a channel.
Optionally, the guard interval adding module 16 is configured to copy and add a data block symbol corresponding to the length of the guard interval at the tail of the cyclic signal sequence to the head of the cyclic signal sequence when the guard interval is added at the head of the cyclic signal sequence.
Referring to fig. 8, a schematic structural diagram of an FTN pre-equalization receiver according to an embodiment of the present invention is shown in fig. 8, where the receiver includes:
a guard interval removing module 21, configured to receive an output signal sequence sent by the FTN pre-equalization transmitter, and remove a guard interval in the output signal sequence to obtain an input signal sequence;
the channel equalization module 22 is configured to perform equalization operation on the input signal sequence to obtain a channel equalization output signal sequence;
and the circular matched filtering module 23 is configured to perform circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence.
Optionally, the guard interval removing module 21 is configured to obtain guard interval configuration information sent by an FTN pre-equalization transmitter, where the guard interval configuration information at least carries a setting position and a length of the guard interval; and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
Optionally, the channel equalization module 22 is configured to, when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, compare the bandwidth with the bandwidth threshold
Carrying out frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence; alternatively, the first and second electrodes may be,
when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence, wherein the loop matching filter module 23 is configured to obtain configuration information of a shaping filter sent by the FTN pre-equalization transmitter, where the configuration information of the shaping filter at least carries a type of the shaping filter used by the FTN pre-equalization transmitter, a nyquist-exceeding shaping filtering displacement amount, and a length of a symbol data block;
according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence;
wherein the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
Referring to fig. 9, a schematic structural diagram of an FTN pre-equalization transmission system according to an embodiment of the present invention is shown in fig. 9, where the transmission system includes an FTN pre-equalization transmitter 31 described in the foregoing embodiment and an FTN pre-equalization receiver 32 described in the foregoing embodiment.
In order to illustrate the effects of the transmission method, the transmitter, the receiver and the system of the super-nyquist rate block provided by the embodiment of the present invention, system simulation is performed in the embodiment of the present invention, and specific system simulation parameter settings are as shown in the following table one:
table one:
Figure BDA0001328334570000151
Figure BDA0001328334570000161
referring to fig. 10, a frequency efficiency result diagram provided by the embodiment of the invention is shown. Fig. 10 shows that different spectral efficiencies may be obtained with different system parameter configurations. As can be seen from the figure, the time compression rate of the Nyquist system is 1, and when QPSK modulation is adopted, the frequency spectrum efficiency is 2 bps/Hz; and when the time compression rate of the FTN-PEQBT system is respectively set to be 0.8, 0.85, 0.9 and 0.95, under the same modulation mode, the spectral efficiency is 2.5, 2.35, 2.22 and 2.11bps/Hz, and the spectral efficiency is improved by 25 to 5.5 percent compared with the former.
Referring to fig. 11, a schematic diagram of a received reconstructed snr result according to an embodiment of the present invention is provided. Fig. 11 shows that different received reconstructed signal-to-noise ratios can be obtained by different system parameter configurations. As can be seen from the figure, the time compression rate of the Nyquist system is 1, and the receiving reconstruction signal-to-noise ratio is completely the same as the signal-to-noise ratio of the AWGN channel; and when the time compression rate of the FTN-PEQBT system is 0.8-0.95, the receiving reconstruction signal-to-noise ratio is gradually improved, namely the receiving reconstruction signal-to-noise ratio is improved along with the reduction of the system spectrum efficiency.
Therefore, the super-Nyquist system provided by the invention can obtain the same spectrum efficiency as the traditional super-Nyquist system and is obviously improved compared with the traditional Nyquist system.
In summary, according to the FTN pre-equalization transmission method, transmitter, receiver, and system provided by the present invention, at the transmitting end, the symbol to be transmitted is divided into blocks, and each symbol block is pre-equalized to eliminate the self-ISI effect caused by the subsequent super-nyquist rate shaping filtering in advance, then the pre-equalized symbol blocks are shaped and filtered according to the super-nyquist rate, then the cyclic superposition operation is performed to form the first-to-last cyclic block symbols that can keep the super-nyquist rate, and finally the guard interval is added to the symbol blocks to form the transmitted baseband symbols. At the receiving end, the ISI caused by the multipath channel is only needed to be eliminated through the guard interval, and the self-ISI influence caused by the transmission at the faster-than-Nyquist rate is not needed to be considered, so that the effect of reducing the complexity of the receiving end is achieved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (29)

1. An FTN pre-equalization transmission method applied to an FTN pre-equalization transmitter, the transmission method comprising the steps of:
dividing the modulation symbol sequence into a plurality of symbol data blocks;
generating a pre-equalization coefficient corresponding to each symbol data block;
according to the pre-equalization coefficient, pre-equalizing the corresponding symbol data block to obtain a pre-equalized signal sequence;
respectively carrying out super-Nyquist shaping filtering on the pre-equalized signal sequence by using a shaping filter to obtain a filtering signal sequence;
performing head-to-tail cyclic superposition on the filtering signal sequence to obtain a cyclic signal sequence;
and adding a guard interval to the circulating signal sequence to obtain an output signal sequence, and sending the output signal sequence to the FTN pre-equalization receiver.
2. An FTN pre-equalization transmission method according to claim 1, wherein the plurality of symbol data blocks are all the same length.
3. An FTN pre-equalization transmission method according to claim 1, wherein said generating pre-equalization coefficients comprises generating the pre-equalization coefficients by a cyclic autocorrelation operation based on discrete impulse responses of shaping filters and displacement of super-nyquist shaping filters;
the length of the pre-equalization coefficient is equal to the length of the symbol data block.
4. FTN pre-equalization transmission method according to claim 1, characterized in that said pre-equalization comprises a frequency domain equalization or a time domain equalization,
performing frequency domain equalization on the symbol data block, wherein the frequency domain equalization comprises calculating a vector division operation result of discrete Fourier transform of the symbol data block and discrete Fourier transform of a pre-equalization coefficient; performing inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence;
performing time domain equalization on the symbol data block, wherein the time domain equalization comprises calculating the reciprocal of the discrete Fourier transform of the pre-equalization coefficient in an off-line manner and then taking the inverse discrete Fourier transform of the pre-equalization coefficient; and performing cyclic convolution operation on the inverse transformation output result and the symbol data block to obtain a pre-equalization signal sequence.
5. An FTN pre-equalization transmission method according to claim 1, wherein the shaping filter has a discrete impulse response with an upsampling rate greater than the amount of the nyquist shaping filter shift.
6. An FTN pre-equalization transmission method according to claim 1, wherein said shaping filter comprises any one of a root-raised cosine filter, a gaussian filter and an isotropic orthogonal transform algorithm filter.
7. An FTN pre-equalization transmission method according to claim 1, wherein the cyclic head-to-tail superposition of the filtered signal sequence to obtain a cyclic signal sequence comprises:
when t is more than or equal to 0 and less than or equal to P-NFTNAt time-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence;
when P-N is presentFTNThe t is more than or equal to Q-1, and the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence;
wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
8. The FTN pre-equalization transmission method of claim 7, wherein a length of the cyclic signal sequence is equal to a product of a length of the symbol data block and a displacement of the faster-than-nyquist shaping filter, and wherein the length of the cyclic signal sequence is greater than or equal to a length of a discrete impulse response of the shaping filter.
9. An FTN pre-equalization transmission method according to claim 1, wherein adding a guard interval to the cyclic signal sequence to obtain an output signal sequence comprises:
and adding the guard interval at the head or the tail of the cyclic signal sequence, wherein the length of the guard interval is greater than or equal to the maximum time delay spread length of the channel.
10. An FTN pre-equalization transmission method according to claim 9, wherein when the guard interval is added to the head of the cyclic signal sequence, a data block symbol corresponding to the length of the guard interval at the end of the cyclic signal sequence is copied and added to the head of the cyclic signal sequence.
11. An FTN pre-equalization transmission method is applied to an FTN pre-equalization receiver and is characterized by comprising the following steps:
receiving an output signal sequence sent by an FTN pre-equalization transmitter, and removing a guard interval in the output signal sequence to obtain an input signal sequence;
performing channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence;
and performing circular matching filtering on the channel equalization output signal sequence to obtain a circular matching signal sequence.
12. An FTN pre-equalization transmission method according to claim 11, wherein receiving an output signal sequence transmitted by a transmitter and removing a guard interval in the output signal sequence to obtain an input signal sequence comprises:
obtaining protection interval configuration information sent by an FTN pre-equilibrium transmitter, wherein the protection interval configuration information at least carries the setting position and the length of the protection interval;
and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
13. An FTN pre-equalization transmission method according to claim 11, wherein performing a channel equalization operation on the input signal sequence when the equalization operation comprises a time domain equalization operation or a frequency domain equalization operation to obtain a channel equalization output signal sequence comprises:
when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, performing frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence; alternatively, the first and second electrodes may be,
and when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
14. An FTN pre-equalization transmission method according to claim 11, wherein performing cyclic matched filtering on the channel equalization output signal sequence to obtain a cyclic matched signal sequence comprises:
acquiring configuration information of a shaping filter sent by an FTN pre-equalization transmitter, wherein the configuration information of the shaping filter at least carries the type of the shaping filter used by the FTN pre-equalization transmitter, the displacement of the super-Nyquist shaping filter and the length of a symbol data block;
according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence;
the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
15. An FTN pre-equalization transmitter, comprising:
a data block dividing module for dividing the modulation symbol sequence into a plurality of symbol data blocks;
the pre-equalization coefficient generating module is used for generating a pre-equalization coefficient corresponding to each symbol data block;
the pre-equalization module is used for pre-equalizing the corresponding symbol data block according to the pre-equalization coefficient to obtain a pre-equalization signal sequence;
the shaping filtering module is used for performing super-Nyquist shaping filtering on the pre-equalized signal sequence by using a shaping filter to obtain a filtering signal sequence;
the cyclic blocking module is used for performing head-to-tail cyclic superposition on the filtering signal sequence to obtain a cyclic signal sequence;
and the guard interval adding module is used for adding a guard interval on the circulating signal sequence to obtain an output signal sequence and sending the output signal sequence to the FTN pre-equalization receiver.
16. The FTN pre-equalization transmitter of claim 15, wherein the plurality of symbol data blocks divided by the data block division block are all the same length.
17. An FTN pre-equalized transmitter according to claim 15, wherein the pre-equalization coefficient generation module is configured to generate the pre-equalization coefficients by a cyclic autocorrelation operation based on discrete impulse responses of shaping filters and displacement of super-nyquist shaping filters;
the length of the pre-equalization coefficient is equal to the length of the symbol data block.
18. The FTN pre-equalization transmitter of claim 17, wherein said pre-equalization block is configured to,
performing frequency domain equalization on the symbol data block, wherein the frequency domain equalization comprises calculating a vector division operation result of discrete Fourier transform of the symbol data block and discrete Fourier transform of a pre-equalization coefficient; performing inverse discrete Fourier transform on the vector division operation result to obtain a pre-equalization signal sequence;
performing time domain equalization on the symbol data block, wherein the time domain equalization comprises calculating the reciprocal of the discrete Fourier transform of the pre-equalization coefficient in an off-line manner and then taking the inverse discrete Fourier transform of the pre-equalization coefficient; and performing cyclic convolution operation on the inverse transformation output result and the symbol data block to obtain a pre-equalization signal sequence.
19. An FTN pre-equalized transmitter according to claim 15, wherein the shaping filter has an upsampling rate greater than the amount of displacement of the faster-than-nyquist shaping filter.
20. An FTN pre-equalization transmitter according to claim 15, wherein said shaping filter comprises any one of a root-raised cosine filter, a gaussian filter and an isotropic orthogonal transform algorithm filter.
21. The FTN pre-equalization transmitter of claim 15, wherein said round-robin blocking block is configured to,
when t is more than or equal to 0 and less than or equal to P-NFTNAt time-1, adding the t data symbol and the t + Q data symbol in the filtered signal sequence to obtain the t data symbol of the cyclic signal sequence;
when P-N is presentFTNThe t is more than or equal to Q-1, and the t data symbol in the filtering signal sequence is used as the t data symbol of the circulating signal sequence;
wherein, P is the length of the filtering signal sequence, Q is the length of the circulating signal sequence, and P is more than Q; n is a radical ofFTNShift amounts for the super-nyquist shaping filter; t, P and Q are all natural numbers.
22. The FTN pre-equalization transmitter of claim 21, wherein the length of the cyclic signal sequence is equal to the product of the length of the symbol data block and the amount of the nyquist shaping filter shift, and wherein the length of the cyclic signal sequence is greater than or equal to the length of the discrete impulse response of the shaping filter.
23. The FTN pre-equalization transmitter of claim 15, wherein the guard interval adding module is configured to add the guard interval at the beginning or the end of the cyclic signal sequence, and wherein the length of the guard interval is greater than or equal to a maximum delay spread length of a channel.
24. The FTN pre-equalization transmitter of claim 23, wherein the guard interval adding module is configured to copy and add a data block symbol corresponding to a length of a guard interval at an end of the cyclic signal sequence to a head of the cyclic signal sequence when the guard interval is added at the head of the cyclic signal sequence.
25. An FTN pre-equalization receiver, comprising:
the protection interval removing module is used for receiving an output signal sequence sent by the FTN pre-equalization transmitter and removing a protection interval in the output signal sequence to obtain an input signal sequence;
the channel equalization module is used for carrying out channel equalization operation on the input signal sequence to obtain a channel equalization output signal sequence;
and the circulating matching filtering module is used for performing circulating matching filtering on the channel equalization output signal sequence to obtain a circulating matching signal sequence.
26. The FTN pre-equalization receiver of claim 25, wherein said guard interval removal block is configured to,
obtaining protection interval configuration information sent by an FTN pre-equilibrium transmitter, wherein the protection interval configuration information at least carries the setting position and the length of the protection interval;
and removing the guard interval in the output signal sequence according to the setting position and the length of the guard interval.
27. The FTN pre-equalization receiver of claim 25, wherein said channel equalization module is configured to,
when the bandwidth of the transmission signal is greater than or equal to the bandwidth threshold, performing frequency domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence; alternatively, the first and second electrodes may be,
and when the bandwidth of the transmission signal is smaller than the bandwidth threshold, performing time domain equalization operation on the input signal sequence to obtain a channel equalization output signal sequence.
28. An FTN pre-equalization receiver according to claim 25, wherein the circular matched filtering block is adapted to,
acquiring configuration information of a shaping filter sent by an FTN pre-equalization transmitter, wherein the configuration information of the shaping filter at least carries the type of the shaping filter used by the FTN pre-equalization transmitter, the displacement of the super-Nyquist shaping filter and the length of a symbol data block;
according to the discrete impulse response of the shaping filter corresponding to the type and the super-Nyquist shaping filtering displacement, carrying out circular matched filtering on the channel equalization output signal sequence to obtain a circular matched signal sequence;
the length of the cyclic matching signal sequence is equal to the length of the symbol data block.
29. An FTN pre-equalization transmission system, comprising an FTN pre-equalization transmission transmitter according to any one of claims 15 to 24 and an FTN pre-equalization transmission receiver according to any one of claims 25 to 28.
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