CN107453853B - Method and device for pilot frequency transmission - Google Patents

Method and device for pilot frequency transmission Download PDF

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Publication number
CN107453853B
CN107453853B CN201610380679.0A CN201610380679A CN107453853B CN 107453853 B CN107453853 B CN 107453853B CN 201610380679 A CN201610380679 A CN 201610380679A CN 107453853 B CN107453853 B CN 107453853B
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training sequence
pilot
target signal
end device
pilot symbol
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CN107453853A (en
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江涛
刘霞东
屈代明
陈磊
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/005—Allocation of pilot signals, i.e. of signals known to the receiver of common pilots, i.e. pilots destined for multiple users or terminals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

The invention discloses a pilot frequency transmission method and pilot frequency transmission equipment, which relate to the field of communication and can improve the accuracy of timing estimation and reduce pilot frequency overhead. The method comprises the following steps: a sending terminal device constructs at least one pilot frequency symbol, wherein each pilot frequency symbol comprises M sub-carriers, a first sub-carrier in the M sub-carriers bears pilot frequency data, and a 4N sub-carrier from the first sub-carrier bears one pilot frequency data at intervals; generating a first training sequence according to the at least one pilot symbol; the first training sequence is used for time offset estimation; and sending the first target signal comprising the first training sequence to receiving end equipment.

Description

Method and device for pilot frequency transmission
Technical Field
The present invention relates to the field of communications, and in particular, to a method and an apparatus for pilot transmission.
Background
In a wireless communication network, generally, the time when a receiving end sends a signal to a sending end is unknown, and in addition, factors such as channel transmission delay and the like cause that the starting point of the signal received by the receiving end is no longer the starting point of the signal sent by the sending end, that is, the signal received by the receiving end has a certain offset, referred to as time offset, in time relative to the signal sent by the sending end.
Meanwhile, because the carrier oscillators of the receiving end and the transmitting end inevitably have difference, and are influenced by the doppler shift and the phase noise in the wireless mobile channel, a certain deviation, referred to as frequency offset for short, exists between the carrier of the signal received by the receiving end and the local carrier of the receiving end.
The time offset estimation of the signal is to find the initial time of the received signal so that the receiving end can correctly demodulate the signal; the frequency offset estimation of the signal is to estimate the frequency deviation of the received signal relative to the transmitted signal for compensation.
For a Filter Bank-based Multicarrier (FBMC) system, the prior art may adopt a data-aided time-frequency estimation scheme: i.e. transmitting a set of successive data before sending itM of (A)TRIs implemented by identical pilot symbols, NTRAt least, the number of the repeated pilot symbols is at least larger than the overlap factor K of the pulse shaping filter g (K), so that the repeated symbols in the time domain training sequence modulated by the transmitting end can be ensured, and the minimum number of the repeated pilot symbols is K + 2.
The existing pilot frequency construction scheme brings considerable pilot frequency overhead, and more importantly, the existing time frequency estimation algorithm generally needs time frequency offset and frequency offset joint estimation and cannot be independently carried out, so that the existing time frequency estimation algorithm is easily influenced by frequency offset when carrying out timing estimation, and the accuracy of the timing estimation is influenced.
Disclosure of Invention
The invention aims to provide a pilot frequency transmission method and equipment, which can improve the accuracy of timing estimation and reduce pilot frequency overhead.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
in a first aspect, a method for pilot transmission is provided, the method comprising: a sending terminal device constructs at least one pilot symbol, wherein each pilot symbol comprises M subcarriers, and M is 2nN is a positive integer greater than or equal to 1; wherein, a first subcarrier in the M subcarriers bears pilot frequency data, and every 4N subcarriers from the first subcarrier bear one pilot frequency data; n is an integer greater than or equal to 0, and the transmitting end equipment generates a first training sequence according to the at least one pilot frequency symbol; the first training sequence is used for time offset estimation; and the sending end equipment sends the first target signal comprising the first training sequence to receiving end equipment.
In the first aspect, the first training sequence generated by the sending end device has a conjugate symmetry characteristic, and when the first training sequence is used for time offset estimation, only time domain parameters are used without considering the frequency domain condition, that is, the influence of frequency offset can be avoided during time offset estimation, so that the accuracy of timing estimation is improved, and because the scheme can adopt only one pilot symbol at least, the pilot overhead is reduced.
With reference to the first aspect, in a first possible implementation manner of the first aspect, a first pilot symbol of the at least one pilot symbol includes M total subcarriers with reference numerals of 0,1, …, and M-1, respectively, and the reference numeral is 4Nm M0The sub-carriers of (a) carry a pilot data respectively; wherein m is0If the first pilot symbol is any one of the at least one pilot symbol, then the generating, by the sending end device, a first training sequence according to the at least one pilot symbol specifically includes: the sending end device generates a first training sequence as shown in the following according to the first pilot symbol:
Figure GDA0002420642620000021
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000022
is pilot data, g (K) is a filter, the truncation length is KM, where K is the overlap factor of the filter, K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000031
Conjugate symmetry, i.e.
Figure GDA0002420642620000032
Wherein, k is 0,1, M/2-1. In a first possible implementation manner of the first aspect, preferably, N is equal to 1, that is, every other 4 subcarriers in the first pilot symbol carry one pilot data.
With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, after the transmitting end device constructs at least one pilot symbol, the method further includes: the sending end equipment inserts a preset number of 0 after the time of the at least one pilot frequency symbol, and constructs data symbols after the time of the preset number of 0; the sending end device generates a first training sequence according to the at least one pilot symbol, and the method includes: generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol. The 0 inserted between the at least one pilot symbol and the data symbol is used to reduce or avoid interference between the data sequence and the first training sequence, wherein the number of the inserted 0 is related to the type of the prototype filter adopted by the transmitting end device, and in specific implementation, the number of the inserted 0 can be preset by analyzing the interference between the symbols according to the type of the prototype filter adopted.
With reference to the first aspect or the first possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the generating, by the sending end device, a first training sequence according to the at least one pilot symbol further includes: the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation; the sending end device sends the first target signal including the first training sequence to a receiving end device, and the sending end device includes: the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device. After receiving the first training sequence and the second training sequence, the receiving end device may obtain a frequency offset value by calculating a correlation between the first training sequence and the second training sequence.
Preferably, in some possible implementations, the first target signal may be a signal generated by the first training sequence, the second training sequence, a preset number of 0's, and data symbols.
In a second aspect, another method for pilot transmission is provided, the method comprising: receiving end equipment receives a second target signal comprising a third training sequence; wherein the second target signal is a first target signal including a first training sequence sent by the sending end device after transmissionA signal received by the receiving end device; the first training sequence is generated from at least one pilot symbol, each of the pilot symbols comprising M subcarriers, wherein M2nN is a positive integer greater than or equal to 1; a first subcarrier in the M subcarriers bears pilot frequency data, and 4N subcarriers from the first subcarrier at intervals bear one pilot frequency data; n is an integer greater than or equal to 0, and the receiving end equipment determines the time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence; and the receiving end equipment carries out frequency offset estimation on the second target signal.
With reference to the second aspect, in a first possible implementation manner of the second aspect, the first training sequence is:
Figure GDA0002420642620000041
wherein n is0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000042
is pilot data, the first pilot symbol comprises a total of M subcarriers, M being numbered 0,1, …, M-1 respectively00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (K) being a filter, a truncation length KM, where K is an overlap factor of the filter, K being a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000043
Conjugate symmetry, i.e.
Figure GDA0002420642620000044
Wherein, k is 0,1, M/2-1;
the determining, by the receiving end device, the time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence includes: the above-mentionedThe receiving end equipment calculates the time offset value of the second target signal r (k) by using the following relation
Figure GDA0002420642620000045
Figure GDA0002420642620000046
Figure GDA0002420642620000047
Figure GDA0002420642620000051
The first possible implementation manner of the second aspect provides a specific algorithm for time offset estimation, and as can be known from the above calculation formula, when performing time offset estimation, no parameter in the frequency domain is involved, so that the influence of frequency offset is avoided, and the accuracy of timing estimation is improved.
With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the performing, by the receiving end device, frequency offset estimation on the second target signal includes: the receiving end equipment utilizes the time offset value
Figure GDA0002420642620000055
Performing time offset compensation on the second target signal; the receiving end equipment performs frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range; the receiving end equipment calculates the correlation between the second target signal after frequency offset compensation and a local training sequence; and the receiving end equipment determines the frequency offset value which enables the correlation between the second target signal after frequency offset compensation and the local training sequence to be maximum as the frequency offset value of the second target signal. That is, the frequency offset value of the second target signal may be calculated by the following formula
Figure GDA0002420642620000052
Figure GDA0002420642620000053
With reference to the second aspect or the first possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the second target signal further includes a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as the first training sequence; the receiving end device performs frequency offset estimation on the second target signal, including: the receiving end equipment calculates correlation information between the third training sequence and the fourth training sequence; and the receiving end equipment determines the frequency offset value of the second target signal according to the correlation information. In particular, the correlation between the third training sequence and the fourth training sequence may be calculated by the following formula:
Figure GDA0002420642620000054
wherein, the estimated value of the frequency deviation is as follows:
Figure GDA0002420642620000061
in a third aspect, a sending end device is provided, including: a constructing unit configured to construct at least one pilot symbol, each of the pilot symbols comprising M subcarriers, wherein M is 2nN is a positive integer greater than or equal to 1; a first subcarrier in the M subcarriers bears pilot frequency data, and 4N subcarriers from the first subcarrier at intervals bear one pilot frequency data; n is an integer greater than or equal to 0, a generating unit configured to generate a first training sequence according to the at least one pilot symbol; the first training sequence is used for time offset estimation; and the sending unit is used for sending the first target signal comprising the first training sequence to receiving end equipment.
With reference to the third aspect, in a first possible implementation manner of the third aspect, the first pilot symbol includes M total subcarriers with reference numbers 0,1, …, and M-1, respectively, and the reference number is 4Nm M0The sub-carriers of (a) carry a pilot data respectively; wherein m is00,1, …, M/4N-1, where the first pilot symbol is any one of the at least one pilot symbol, and the generating unit is specifically configured to: generating a first training sequence according to the first pilot symbols as follows:
Figure GDA0002420642620000062
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000063
is pilot data, g (K) is a filter, the truncation length is KM, where K is the overlap factor of the filter, K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000064
Conjugate symmetry, i.e.
Figure GDA0002420642620000065
Wherein, k is 0,1, M/2-1.
With reference to the third aspect, or the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the constructing unit is further configured to, after constructing at least one pilot symbol: inserting a preset number of 0's after the time of the at least one pilot symbol, and constructing data symbols after the time of the preset number of 0's; the generating unit is specifically configured to: generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol.
With reference to the third aspect or the first possible implementation manner of the third aspect, in a third possible implementation manner of the third aspect, the at least one pilot symbol further includes a second pilot symbol, and the generating unit is specifically configured to: the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation; the sending unit is specifically configured to: the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device.
In a fourth aspect, a receiving end device is provided, including: a receiving unit, configured to receive a second target signal including a third training sequence; the second target signal is a signal which is transmitted by the sending end device and received by the receiving end device after the first target signal including the first training sequence is sent by the sending end device; the first training sequence is generated from at least one pilot symbol, each of the pilot symbols comprising M subcarriers, wherein M2nN is a positive integer greater than or equal to 1; a first subcarrier in the M subcarriers bears pilot frequency data, and 4N subcarriers from the first subcarrier at intervals bear one pilot frequency data; n is an integer greater than or equal to 0; a first estimating unit, configured to determine a time offset value of the second target signal by using a time domain parameter of the third training sequence according to a conjugate symmetry characteristic of the third training sequence; and the second estimation unit is used for carrying out frequency offset estimation on the second target signal.
With reference to the fourth aspect, in a first possible implementation manner of the fourth aspect, the first training sequence is:
Figure GDA0002420642620000071
wherein n is0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000072
is pilot data, the first pilot symbol comprises a total of M subcarriers numbered 0,1, …, M-1,m 00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (K) being a filter, a truncation length KM, where K is an overlap factor of the filter, K being a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000073
Conjugate symmetry, i.e.
Figure GDA0002420642620000074
Wherein, k is 0,1, M/2-1;
the first estimating unit is specifically configured to calculate a time offset value of the second target signal r (k) by using the following relation
Figure GDA0002420642620000081
Figure GDA0002420642620000082
Figure GDA0002420642620000083
Figure GDA0002420642620000084
With reference to the first possible implementation manner of the fourth aspect, in a second possible implementation manner of the fourth aspect, the apparatus further includes a compensation unit, configured to utilize the time offset value
Figure GDA0002420642620000085
Performing time offset compensation on the second target signal; performing frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range; the second estimating unit is specifically configured to calculate a correlation between the second target signal after frequency offset compensation and the local training sequence, and determine a frequency that maximizes the correlation between the second target signal after frequency offset compensation and the local training sequenceThe offset value is the frequency offset value of the second target signal.
With reference to the fourth aspect or the first possible implementation manner of the fourth aspect, in a second possible implementation manner of the fourth aspect, the second target signal further includes a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as and adjacent to the first training sequence; the second estimating unit is specifically configured to calculate correlation information between the third training sequence and the fourth training sequence, and determine a frequency offset value of the second target signal according to the correlation information.
In a fifth aspect, a sending end device is provided, where the sending end device includes: a processor, a memory, a communication interface, and a communication bus; the processor, the memory, and the communication interface communicate over the communication bus; the processor is configured to perform the method of the first aspect or any possible implementation manner of the first aspect.
In a sixth aspect, a receiving end device is provided, where the receiving end device includes: a processor, a memory, a communication interface, and a communication bus; the processor, the memory, and the communication interface communicate over the communication bus; the processor is configured to perform the method of the second aspect or any possible implementation manner of the second aspect.
In a seventh aspect, a computer-readable medium is provided for storing a computer program comprising instructions for performing the method of the first aspect or any possible implementation manner of the first aspect.
In an eighth aspect, there is provided a computer readable medium for storing a computer program comprising instructions for performing the method of the second aspect or any possible implementation of the second aspect.
The invention can be further combined to provide more implementation modes on the basis of the implementation modes provided by the aspects.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of a pilot symbol transmitted to a receiving end device by a sending end device before sending data according to an embodiment of the present invention;
fig. 2 is a flowchart illustrating a method for pilot transmission according to an embodiment of the present invention;
FIG. 3 is a diagram of pilot symbols constructed in accordance with an embodiment of the present invention;
fig. 4 is a schematic diagram of a receiving end device generating a training sequence according to a pilot symbol according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a first training sequence according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another first training sequence according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a sending-end device according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a receiving end device according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of another sending-end device according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of another receiving end device according to an embodiment of the present invention.
Detailed Description
In order to make it easier for those skilled in the art to understand the technical solution provided by the present invention as an improvement over the prior art, the prior art will first be briefly described.
Fig. 1 is a diagram illustrating a pilot symbol transmitted from a transmitting device to a receiving device before transmitting data in the prior art,as shown, each time instant in the time domain includes a pilot symbol, and each pilot symbol includes a plurality of subcarriers in the frequency domain. It should be noted that if the number of repeated symbols in the training sequence is required to be NripThen the number of pilot symbols that the transmitting end device needs to transmit is at least NTR＝Nrip+ K, wherein, NTRAt least larger than the overlap factor K of the pulse shaping filter g (K).
The embodiment of the invention can send the pilot frequency symbol with a specific structure on the subcarrier within a single symbol time to obtain the training sequence with conjugate symmetry characteristic, thereby improving the accuracy of timing estimation while reducing the pilot frequency overhead.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The technical solutions provided by the following embodiments of the present invention may be applied to a wireless communication network, for example: long Term Evolution (LTE) systems, long term evolution advanced (LTE-a) systems, and further evolution networks thereof.
A Base Station (BS) and a User Equipment (UE) may be included in a wireless communication network. The receiving end device described in the following embodiments of the present invention may be a base station in an FBMC system, and the transmitting end device may be a user equipment in the FBMC system.
The base station may be a device that communicates with a user equipment or other communication station, such as a relay station. For example, the base station may specifically be an evolved node B (ENB or eNodeB) in LTE; or may be other access network devices providing access services in a wireless communication network.
UEs may be distributed throughout a wireless network and may be referred to as terminals (terminals), mobile stations (mobile stations), subscriber units (subscriber units), stations (stations), etc. The UE may specifically be a cellular phone (cellular phone), a Personal Digital Assistant (PDA), a handheld device (hand-held device), a laptop computer (laptop computer), and other wireless communication devices.
An embodiment of the present invention provides a method for pilot transmission, as shown in fig. 2, the method includes:
s201, a sending end device constructs at least one pilot symbol, wherein each pilot symbol comprises M sub-carriers, a first sub-carrier in the M sub-carriers bears pilot data, and the pilot data starts from the first sub-carrier.
Wherein N is an integer of 0 or more, and M is 2nAnd n is a positive integer greater than or equal to 1.
Illustratively, N is equal to 1, that is, the first pilot symbol carries one pilot data every 4 subcarriers, i.e., where m is 4m0As shown in fig. 3, if M is equal to 8, the subcarriers numbered 0 and 4 in the first pilot symbol carry pilot data, and the subcarriers numbered 1, 2, 3, 5,6, and 7 do not carry pilot data.
It should be noted that, the above is only exemplified by N ═ 1, and in a specific implementation, N may be another positive integer, which is not limited in the present invention.
S202, the sending end equipment generates a first training sequence according to the at least one pilot frequency symbol; the first training sequence is used for time offset estimation.
FIG. 4 shows a transmitting end device according to the method at n0Each subcarrier of time input
Figure GDA0002420642620000111
To
Figure GDA0002420642620000112
Obtaining the training sequence s via a filter g (k)0(k) Schematic illustration of。
Specifically, a first pilot symbol of the at least one pilot symbol comprises a total of M subcarriers with reference numerals 0,1, …, M-1, respectively, and with reference numeral 4Nm M0The sub-carriers of (a) carry a pilot data respectively; wherein m is0If 0,1, …, and M/4N-1, the generating, by the sending end device, a first training sequence according to the at least one pilot symbol specifically includes:
with reference to fig. 4, the transmitting end device may generate a first training sequence according to the first pilot symbol, where the first training sequence is as follows:
Figure GDA0002420642620000121
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000122
is pilot data, g (K) is a filter, and the truncation length is KM, wherein K is the overlapping factor of the filter, and K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000123
Conjugate symmetry, i.e.
Figure GDA0002420642620000124
Wherein, k is 0,1, M/2-1.
Still exemplified by N ═ 1, the expression of the first training sequence can be found as:
Figure GDA0002420642620000125
further, it is possible to obtain:
Figure GDA0002420642620000126
in general, the prototype filter g (k) is true symmetric when its truncation length is largeAt 4M, there are: g (k) ═ g (4M-k), then further:
Figure GDA0002420642620000127
thus, at n0In the case of an even number, it is possible to transmit the desired pilot data only in the real part of the pilot symbols, and, at this time,
Figure GDA0002420642620000128
namely:
Figure GDA0002420642620000129
therefore, the first training sequence generated corresponding to the pilot symbols constructed by the transmitting terminal equipment is related to
Figure GDA00024206426200001210
Conjugate symmetry, as shown in fig. 5, the first training sequence includes two segments of Syn1 generated by the first M/2 sub-carriers and Syn1' generated by the last M/2 sub-carriers, and the two segments of sequences are conjugate symmetric. And the time-frequency estimation can be carried out by utilizing the conjugate symmetry characteristic.
S203, the sending end device sends the first target signal including the first training sequence to a receiving end device.
It is noted that the first target signal may also include other sequences, as will be described in detail later.
S204, the receiving end equipment receives a second target signal comprising a third training sequence; the second target signal is a signal which is transmitted by the sending end device and received by the receiving end device after the first target signal including the first training sequence is transmitted.
That is to say, the third training sequence is a sequence after a time-frequency offset is generated by transmission of the first training sequence received by the receiving end device.
S205, the receiving end device determines the time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence.
Specifically, the receiving end device may calculate a time offset value of the second target signal r (k) by using the following relation
Figure GDA0002420642620000131
Figure GDA0002420642620000132
As described above
Figure GDA0002420642620000133
And
Figure GDA0002420642620000134
is the intermediate value generated by calculation, and those skilled in the art should understand that the above relation is the calculation result generated according to the conjugate symmetry property of the first training sequence, and will not be described herein again. According to the above relation, the receiving end device only needs to use the time domain parameter for calculating the time offset value, and does not need to consider the frequency domain condition, that is, the influence of frequency offset can be avoided during time offset estimation, and the accuracy of the timing estimation is improved.
S206, the receiving end device carries out frequency offset estimation on the second target signal.
In the embodiment of the present invention, two implementation manners are provided for frequency offset estimation:
first, the receiving end device utilizes the time offset value
Figure GDA0002420642620000146
Performing time offset compensation on the second target signal; performing frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range; calculating the correlation between the second target signal after frequency offset compensation and a local training sequence; and determining a frequency offset value which enables the correlation between the second target signal after frequency offset compensation and a local training sequence to be maximum as the frequency offset value of the second target signal.
For example, if the local training sequence generated by the receiving end device is s (k), the time offset value is used after the receiving end device receives the second target signal r (k)
Figure GDA0002420642620000141
Compensating the second target signal r (k) by using an estimated frequency offset value
Figure GDA0002420642620000142
Compensating the second target information after time offset compensation, further, performing cross-correlation operation on the signals after the local training sequences s (k) and r (k) compensate the frequency offset, when the correlation result reaches the maximum value,
Figure GDA0002420642620000143
i.e., close to the true frequency offset value, i.e., the estimated value of the frequency offset is calculated as:
Figure GDA0002420642620000144
it is noted that, in practice,
Figure GDA0002420642620000145
the estimated frequency offset value obtained by searching the whole frequency offset range by the receiving end device according to a certain search step length may be the estimated frequency offset value obtained by random search, which is not limited in the present invention.
In a second mode, the at least one pilot symbol includes the first pilot symbol and a second pilot symbol; step S203 specifically includes generating the first training sequence and a second training sequence that is the same as the first training sequence according to the first pilot symbol and the second pilot symbol, where the second training sequence is used for frequency offset estimation, and then step S203 specifically includes: the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device. In this way, the second target signal received by the receiving end device further includes a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after the second training sequence generated by the sending end device is transmitted; step S206 specifically includes: the receiving end equipment calculates correlation information between the third training sequence and the fourth training sequence; and the receiving end equipment determines the frequency offset value of the second target signal according to the correlation information.
Illustratively, as shown in fig. 6, the first target signal specifically includes a first training sequence, a second training sequence identical to the first training sequence, and a data sequence, wherein an interval point d between the first training sequence and the second training sequence is known. Thus, in particular implementation, the correlation between the third training sequence and the fourth training sequence can be calculated by the following formula:
Figure GDA0002420642620000151
wherein, the estimated value of the frequency deviation is as follows:
Figure GDA0002420642620000152
by adopting the method for transmitting the pilot frequency provided by the embodiment of the invention, the first training sequence generated by the sending end equipment has the characteristic of conjugate symmetry, when the first training sequence is utilized for time offset estimation, only time domain parameters are needed to be used, and the condition of a frequency domain does not need to be considered, namely, the influence of frequency offset can be avoided when the time offset estimation is carried out, the accuracy of timing estimation is improved, and in addition, only one pilot frequency symbol can be adopted in the scheme at least, so the pilot frequency overhead is reduced.
In addition, it is worth explaining that, in the FBMC system, because each subcarrier is subjected to pulse forming by using a time-frequency localized filter, the symbols of the time domain synthesis signal in which the subcarriers are superimposed have a tailing addition phenomenon. A certain number of 0S may be inserted at the time after the pilot symbol is sent, and then the data symbol is at the time after the certain number of 0S, that is, after the sending-end device constructs at least one pilot symbol, a preset number of 0S may be inserted after the time of the at least one pilot symbol, and the data symbol is constructed after the time of the preset number of 0S, so that step S202 specifically includes: the sending end device generates the first target signal by using the at least one pilot symbol, the preset number of 0 s and the data symbol.
As shown in fig. 3, the first pilot symbol further includes 4 0 s to reduce or avoid interference of the data sequence with the training sequence.
The number of 0 s to be inserted is related to the type of the prototype filter used by the transmitting end device, and in specific implementation, the interference situation between symbols can be analyzed according to the type of the prototype filter used, and the number of 0 s to be inserted is preset, so as to achieve better time-frequency estimation accuracy under the condition of pilot frequency overhead as small as possible.
In addition, if the receiving end device performs frequency offset estimation in the second manner, the first target signal may also be a signal generated by the electronic device according to the first pilot symbols, the second pilot symbols, and the preset number of 0's and data symbols. And will not be described in detail herein.
An embodiment of the present invention further provides a sending end device 70, configured to implement the method steps corresponding to the sending end device in the above method implementation, as shown in fig. 7, where the sending end device 70 includes:
a constructing unit 71, configured to construct at least one pilot symbol, each of which includes M subcarriers, where M is 2nN is a positive integer greater than or equal to 1; a first subcarrier in the M subcarriers bears pilot frequency data, and 4N subcarriers from the first subcarrier at intervals bear one pilot frequency data; n is an integer greater than or equal to 0.
A generating unit 72, configured to generate a first training sequence according to the at least one pilot symbol; the first training sequence is used for time offset estimation.
A sending unit 73, configured to send a first target signal including the first training sequence to a receiving end device.
By adopting the sending end equipment, the first training sequence generated by the sending end equipment has the characteristic of conjugate symmetry, when the first training sequence is utilized for time offset estimation, only time domain parameters are needed to be used, the condition of a frequency domain does not need to be considered, namely, the influence of frequency offset can be avoided when the time offset estimation is carried out, the accuracy of timing estimation is improved, and in addition, only one pilot frequency symbol can be adopted at least in the scheme, so the pilot frequency overhead is reduced.
Specifically, a first pilot symbol of the at least one pilot symbol comprises a total of M subcarriers with reference numerals 0,1, …, M-1, respectively, and with reference numeral 4Nm M0The sub-carriers of (a) carry a pilot data respectively; wherein m is0If 0,1, …, M/4N-1, the first pilot symbol is any one of the at least one pilot symbol, then the generating unit 72 is specifically configured to generate a first training sequence as shown below according to the first pilot symbol:
Figure GDA0002420642620000171
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000172
is pilot data, g (K) is a filter, the truncation length is KM, where K is the overlap factor of the filter, K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000173
Conjugate symmetry, i.e.
Figure GDA0002420642620000174
Wherein, k is 0,1, M/2-1. Preferably, N is equal to 1, that is, every other 4 subcarriers in the first pilot symbol carry one pilot data.
Optionally, the constructing unit 71 is further configured to, after constructing at least one pilot symbol: inserting a preset number of 0's after the time of the at least one pilot symbol, and constructing data symbols after the time of the preset number of 0's; the generating unit 72 is specifically configured to: generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol. The 0 inserted between the at least one pilot symbol and the data symbol is used to reduce or avoid interference between the data sequence and the first training sequence, wherein the number of 0 inserted is related to the type of prototype filter used by the transmitting end device, and in specific implementation, the number of 0 inserted can be preset by analyzing the interference between symbols according to the type of prototype filter used.
Optionally, the at least one pilot symbol further includes a second pilot symbol, and the generating unit 72 is specifically configured to: the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation; the sending unit 73 is specifically configured to: the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device. After receiving the first training sequence and the second training sequence, the receiving end device may obtain a frequency offset value by calculating a correlation between the first training sequence and the second training sequence.
It should be noted that the above unit division of the sending-end device 70 is only one logic function division, and there may be another division manner in actual implementation, for example, the above-mentioned constructing unit 71 and the generating unit 72 may be divided into one processing unit, and there may be multiple implementation manners for the physical implementation of each functional unit, for example, the above-mentioned constructing unit 71 may specifically be a central processing unit, and may also be A Specific Integrated Circuit (ASIC).
In addition, it should be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the units of the sending-end device 70 described above may refer to corresponding processes in the foregoing method embodiments, and are not described herein again.
An embodiment of the present invention further provides a receiving end device 80, configured to implement the method steps corresponding to the receiving end device in the foregoing method embodiment, as shown in fig. 8, where the receiving end device 80 includes:
a receiving unit 81 for receiving a second target signal including a third training sequence; the second target signal is a signal which is transmitted by the sending end device and received by the receiving end device after the first target signal including the first training sequence is sent by the sending end device; the first training sequence is generated from at least one pilot symbol, each of the pilot symbols comprising M subcarriers, wherein M2nN is a positive integer greater than or equal to 1, a first subcarrier of the M subcarriers carries pilot data, and every 4N subcarriers from the first subcarrier carries pilot data; n is an integer greater than or equal to 0.
A first estimating unit 82, configured to determine a time offset value of the second target signal by using a time domain parameter of the third training sequence according to a conjugate symmetry characteristic of the third training sequence;
a second estimating unit 83, configured to perform frequency offset estimation on the second target signal.
Specifically, the first training sequence is:
Figure GDA0002420642620000181
wherein n is0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000182
is pilot data, the first pilot symbol comprises a total of M subcarriers, M being numbered 0,1, …, M-1 respectively00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (k)) A filter, with a truncation length of KM, where K is the overlap factor of the filter, and K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000183
Conjugate symmetry, i.e.
Figure GDA0002420642620000184
Wherein, k is 0,1, M/2-1; the first estimation unit 82 is specifically configured to calculate the time offset of the second target signal r (k) by using the following relation
Figure GDA0002420642620000191
Figure GDA0002420642620000192
Optionally, the receiving end device 80 further includes a compensation unit 84 for utilizing the time offset value
Figure GDA0002420642620000193
Performing time offset compensation on the second target signal; performing frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range; the second estimating unit 83 is specifically configured to calculate a correlation between the frequency offset-compensated second target signal and the local training sequence, and determine a frequency offset value that maximizes the correlation between the frequency offset-compensated second target signal and the local training sequence as the frequency offset value of the second target signal.
For example, if the local training sequence generated by the receiving end device is s (k), the time offset value is used after the receiving end device receives the second target signal r (k)
Figure GDA0002420642620000194
Compensating the second target signal r (k) by using an estimated frequency offset value
Figure GDA0002420642620000195
Compensating the second target information after time offset compensation, further, performing cross-correlation operation on the signals after the local training sequences s (k) and r (k) compensate the frequency offset, when the correlation result reaches the maximum value,
Figure GDA0002420642620000196
i.e., close to the true frequency offset value, i.e., the estimated value of the frequency offset is calculated as:
Figure GDA0002420642620000197
it is noted that, in practice,
Figure GDA0002420642620000198
the estimated frequency offset value obtained by searching the whole frequency offset range by the receiving end device according to a certain search step length may be the estimated frequency offset value obtained by random search, which is not limited in the present invention.
Optionally, the second target signal further includes a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as the first training sequence; the second estimating unit 83 is specifically configured to calculate correlation information between the third training sequence and the fourth training sequence, and determine a frequency offset value of the second target signal according to the correlation information.
As shown in fig. 6, the first target signal includes a first training sequence, a second training sequence identical to the first training sequence, and a data sequence, wherein an interval point d between the first training sequence and the second training sequence is known. Thus, in particular implementation, the correlation between the third training sequence and the fourth training sequence can be calculated by the following formula:
Figure GDA0002420642620000201
wherein, the estimated value of the frequency deviation is as follows:
Figure GDA0002420642620000202
it should be noted that the above division of the unit of the receiving end device 80 is only one logical function division, and there may be another division manner in actual implementation, and there may be multiple implementation manners for the physical implementation of each functional unit, which is not limited in the present invention.
In addition, it should be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of each unit of the receiving end device 80 described above may refer to corresponding processes in the foregoing method embodiments, and are not described herein again.
An embodiment of the present invention further provides another sending-end device 90, and as shown in fig. 9, the sending-end device 90 includes:
a processor (processor)91, a communication Interface (Communications Interface)92, a memory (memory)93, and a communication bus 94; wherein, the processor 91, the communication interface 92 and the memory 93 complete the communication with each other through the communication bus 94.
The processor 91 may be a multi-core central processing unit CPU, or a specific integrated circuit ASIC, or one or more integrated circuits configured to implement embodiments of the present invention.
The memory 93 is used to store program code including computer operating instructions and network flow diagrams. The Memory 93 may include a high-speed Random Access Memory (RAM) and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The memory 93 may also be a memory array. The storage 93 may also be partitioned and the blocks may be combined into virtual volumes according to certain rules.
The communication interface 92 is used for implementing connection communication between the receiving end devices.
The processor 91 is configured to execute the program code in the memory 93 to perform the following operations:
constructing at least one pilot symbol, each of the pilot symbols comprising M subcarriers, wherein a first subcarrier of the M subcarriers carries data, and M2nN is a positive integer greater than or equal to 1; carrying pilot frequency data by every 4N subcarriers from the first subcarrier; n is an integer greater than or equal to 0;
generating a first training sequence according to the at least one pilot symbol; the first training sequence is used for time offset estimation;
and sending the first target signal comprising the first training sequence to receiving end equipment.
Optionally, the first pilot symbol comprises M total subcarriers numbered 0,1, …, M-1, respectively, and is numbered 4Nm0The sub-carriers of (a) carry a pilot data respectively; wherein m is0If the first pilot symbol is any one of the at least one pilot symbol, 0,1, …, and M/4N-1, the generating a first training sequence according to the at least one pilot symbol specifically includes:
generating a first training sequence according to the first pilot symbols as follows:
Figure GDA0002420642620000211
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000212
is pilot data, g (K) is a filter, the truncation length is KM, where K is the overlap factor of the filter, K is a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000213
Conjugate symmetry, i.e.
Figure GDA0002420642620000214
Wherein, k is 0,1, M/2-1.
Optionally, after the transmitting end device constructs at least one pilot symbol, the method further includes:
the sending end equipment inserts a preset number of 0 after the time of the at least one pilot frequency symbol, and constructs data symbols after the time of the preset number of 0;
the sending end device generates a first training sequence according to the at least one pilot symbol, and the method includes:
generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol.
Optionally, the at least one pilot symbol further includes a second pilot symbol, and the generating, by the sending end device, a first training sequence according to the at least one pilot symbol includes:
the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation;
the sending end device sends the first target signal including the first training sequence to a receiving end device, and the sending end device includes:
the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device.
It should be noted that the sending-end device 90 may specifically be a base station, which may further include other devices, which are not shown in fig. 9. Moreover, those skilled in the art should understand that the operations performed by the processor 91 may be performed by cooperation of other devices, and for convenience of description, the operations performed by the processor 91 to transmit the pilot are collectively described in the embodiments of the present invention.
In addition, the processor 91 in the embodiment of the present invention may be a Central Processing Unit (CPU). To save the computing resources of the CPU, the processor 91 may also be a Field Programmable Gate Array (FPGA) or other hardware to implement the whole operation of transmitting the pilot in the embodiment of the present invention. The processor 91 may also be a CPU and an FPGA, and the FPGA and the CPU respectively execute part of operations of transmitting the pilot in the embodiment of the present invention. For convenience of description, the embodiment of the present invention is described in a unified manner that the processor 91 implements the operation of transmitting the pilot by the sending-end device 90 in the embodiment of the present invention, and specific reference may be made to the description corresponding to the above method embodiment, which is not described herein again.
By adopting the above sending end device 90, the first training sequence generated by the sending end device 90 has the characteristic of conjugate symmetry, when the first training sequence is used for time offset estimation, only the time domain parameter is needed to be used, and the frequency domain condition is not needed to be considered, that is, the influence of frequency offset can be avoided when time offset estimation is performed, the accuracy of timing estimation is improved, and because the scheme can adopt only one pilot frequency symbol at least, the pilot frequency overhead is reduced.
An embodiment of the present invention further provides another sending-end device 10, and as shown in fig. 10, the sending-end device 90 includes:
a processor 101, a communication interface 102, a memory 103, and a communication bus 104; the processor 101, the communication interface 102 and the memory 103 complete communication with each other through the communication bus 104.
The processor 101 may be a multi-core central processing unit CPU, or a specific integrated circuit ASIC, or one or more integrated circuits configured to implement embodiments of the present invention.
The memory 103 is used to store program code, including computer operating instructions and network flow diagrams. Memory 103 may comprise high speed random access memory and may also include non-volatile memory, such as at least one disk memory. The memory 103 may also be a memory array. The storage 103 may also be partitioned and the blocks may be combined into virtual volumes according to certain rules.
The communication interface 102 is configured to implement connection communication with a sending-end device.
The processor 101 is configured to execute the program code in the memory 103 to implement the following operations:
receiving a second target signal comprising a third training sequence; the second target signal is a signal which is transmitted by the sending end device and received by the receiving end device after the first target signal including the first training sequence is sent by the sending end device; the first training sequence is generated according to at least one pilot symbol, each of which comprises M subcarriers, wherein a first subcarrier of the M subcarriers carries pilot data, and M ═ 2nN is a positive integer greater than or equal to 1; carrying pilot frequency data by every 4N subcarriers from the first subcarrier; n is an integer greater than or equal to 0;
determining a time offset value of the second target signal by using a time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence;
and carrying out frequency offset estimation on the second target signal.
Optionally, the first training sequence is:
Figure GDA0002420642620000241
wherein n is0Is the time instant of the first pilot symbol,
Figure GDA0002420642620000242
is pilot data, the first pilot symbol comprises a total of M subcarriers, M being numbered 0,1, …, M-1 respectively00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (K) being a filter, a truncation length KM, where K is an overlap factor of the filter, K being a positive integer greater than or equal to 1; the training sequence relates to
Figure GDA0002420642620000243
Conjugate symmetry, i.e.
Figure GDA0002420642620000244
Wherein, k is 0,1, M/2-1;
determining a time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence, including:
calculating the time offset of the second target signal r (k) by using the following relation
Figure GDA0002420642620000245
Figure GDA0002420642620000246
Figure GDA0002420642620000247
Figure GDA0002420642620000248
Optionally, the performing frequency offset estimation on the second target signal includes:
using said time offset value
Figure GDA0002420642620000249
Performing time offset compensation on the second target signal;
performing frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range;
calculating the correlation between the second target signal after frequency offset compensation and a local training sequence;
and determining a frequency offset value which enables the correlation between the second target signal after frequency offset compensation and a local training sequence to be maximum as the frequency offset value of the second target signal.
Optionally, the second target signal further includes a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as the first training sequence;
the performing frequency offset estimation on the second target signal includes:
calculating correlation information between the third training sequence and the fourth training sequence;
and determining the frequency offset value of the second target signal according to the correlation information.
It should be noted that the receiving end device 10 may specifically be a user device, which may further include other devices, which are not shown in fig. 10. Moreover, it should be understood by those skilled in the art that the operations performed by the processor 101 may be performed by cooperation of other devices, and for convenience of description, the embodiments of the present invention are collectively described as the processor 101 performing the operations. Reference may be made to the corresponding description of the above method embodiments, which is not repeated herein.
In addition, the processor 101 in the embodiment of the present invention may be a central processing unit. To save the computing resources of the CPU, the processor 101 may also be a field programmable gate array or other hardware to implement the whole operation of transmitting the pilot in the embodiment of the present invention. The processor 91 may also be a CPU and an FPGA, and the FPGA and the CPU respectively execute part of the operations in the embodiment of the present invention.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute some steps of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a RAM, a magnetic disk, or an optical disk.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (14)

1. A method for pilot transmission, the method comprising:
a sending terminal device constructs at least one pilot symbol, wherein each pilot symbol comprises M subcarriers, and M is 2nN is a positive integer greater than or equal to 1, whichA first subcarrier of the M subcarriers carries pilot data, and 4N subcarriers from the first subcarrier at intervals carry one pilot data; n is an integer greater than or equal to 0;
the sending end equipment generates a first training sequence according to the at least one pilot frequency symbol; the first training sequence is used for time offset estimation;
the sending end equipment sends a first target signal comprising the first training sequence to receiving end equipment;
wherein a first pilot symbol of the at least one pilot symbol comprises M subcarriers with labels of 0,1, …, M-1, respectively, and the label is 4Nm0The sub-carriers of (a) carry a pilot data respectively; wherein m is00,1, …, M/4N-1, the sending end device generates a first training sequence according to the at least one pilot symbol, including:
the sending end device generates a first training sequence as shown in the following according to the first pilot symbol:
Figure FDA0002420642610000011
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure FDA0002420642610000012
is pilot data, g (K) is a filter, and the truncation length is KM, wherein K is an overlapping factor of the filter, and K is a positive integer greater than or equal to 1; the training sequence relates to
Figure FDA0002420642610000013
Conjugate symmetry, i.e.
Figure FDA0002420642610000014
Wherein, k is 0,1, M/2-1.
2. The method of claim 1, wherein after the transmitting device constructs at least one pilot symbol, further comprising:
the sending end equipment inserts a preset number of 0 after the time of the at least one pilot frequency symbol, and constructs data symbols after the time of the preset number of 0;
the sending end device generates a first training sequence according to the at least one pilot symbol, and the method includes:
generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol.
3. The method of claim 1, wherein the at least one pilot symbol further comprises a second pilot symbol, and wherein the transmitting device generates a first training sequence based on the at least one pilot symbol, comprising:
the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation;
the sending end device sends the first target signal including the first training sequence to a receiving end device, and the sending end device includes:
the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device.
4. A method for pilot transmission, the method comprising:
receiving end equipment receives a second target signal comprising a third training sequence; the second target signal is a signal which is transmitted by the sending end device and received by the receiving end device after the first target signal including the first training sequence is sent by the sending end device; the first training sequence is generated according to at least one pilot symbol, each of which comprises M subcarriers, wherein a first subcarrier of the M subcarriers carries pilot data, and M ═ 2nN is a positive integer greater than or equal to 1; carrying pilot frequency data by every 4N subcarriers from the first subcarrier; n is an integer greater than or equal to 0, and the first training sequence is as follows:
Figure FDA0002420642610000021
wherein n is0Is the time instant of the first pilot symbol,
Figure FDA0002420642610000022
is pilot data, the first pilot symbol comprises a total of M subcarriers, M being numbered 0,1, …, M-1 respectively00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (K) being a filter, a truncation length KM, where K is an overlap factor of the filter, K being a positive integer greater than or equal to 1; the training sequence relates to
Figure FDA0002420642610000031
Conjugate symmetry, i.e.
Figure FDA0002420642610000032
Wherein, k is 0,1, M/2-1;
the receiving end equipment determines the time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence;
and the receiving end equipment carries out frequency offset estimation on the second target signal.
5. The method of claim 4,
the determining, by the receiving end device, the time offset value of the second target signal by using the time domain parameter of the third training sequence according to the conjugate symmetry characteristic of the third training sequence includes:
the receiving end equipment calculates a second target signal r (k) by using the following relational expressionTime offset value of
Figure FDA0002420642610000033
Figure FDA0002420642610000034
Figure FDA0002420642610000035
Figure FDA0002420642610000036
6. The method of claim 5, wherein the receiving device performs frequency offset estimation on the second target signal, and comprises:
the receiving end equipment utilizes the time offset value
Figure FDA0002420642610000037
Performing time offset compensation on the second target signal;
the receiving end equipment performs frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range;
the receiving end equipment calculates the correlation between the second target signal after frequency offset compensation and a local training sequence;
and the receiving end equipment determines the frequency offset value which enables the correlation between the second target signal after frequency offset compensation and the local training sequence to be maximum as the frequency offset value of the second target signal.
7. The method of claim 4 or 5, wherein the second target signal further comprises a fourth training sequence; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as the first training sequence;
the receiving end device performs frequency offset estimation on the second target signal, including:
the receiving end equipment calculates correlation information between the third training sequence and the fourth training sequence;
and the receiving end equipment determines the frequency offset value of the second target signal according to the correlation information.
8. A transmitting-end device, comprising:
a constructing unit for constructing at least one pilot symbol, each of the pilot symbols comprising M sub-carriers, M2nN is a positive integer greater than or equal to 1; wherein, a first subcarrier in the M subcarriers bears pilot frequency data, and every 4N subcarriers from the first subcarrier bear one pilot frequency data; n is an integer greater than or equal to 0;
a generating unit, configured to generate a first training sequence according to the at least one pilot symbol; the first training sequence is used for time offset estimation;
a sending unit, configured to send a first target signal including the first training sequence to a receiving end device;
wherein a first pilot symbol of the at least one pilot symbol comprises M subcarriers with labels of 0,1, …, M-1, respectively, and the label is 4Nm0The sub-carriers of (a) carry a pilot data respectively; wherein m is00,1, …, M/4N-1, the generating unit is specifically configured to:
generating a first training sequence according to the first pilot symbols as follows:
Figure FDA0002420642610000041
wherein s is0(k) For the training sequence, n0Is the time instant of the first pilot symbol,
Figure FDA0002420642610000042
is pilot data, g (K) is a filter, and the truncation length is KM, wherein K is an overlapping factor of the filter, and K is a positive integer greater than or equal to 1; the training sequence relates to
Figure FDA0002420642610000043
Conjugate symmetry, i.e.
Figure FDA0002420642610000051
Wherein, k is 0,1, M/2-1.
9. The transmitting end device of claim 8, wherein the constructing unit, after constructing at least one pilot symbol, is further configured to: inserting a preset number of 0's after the time of the at least one pilot symbol, and constructing data symbols after the time of the preset number of 0's;
the generating unit is specifically configured to: generating the first target signal using the at least one pilot symbol, the preset number of 0's and the data symbol.
10. The sending end device of claim 8, wherein the at least one pilot symbol further includes a second pilot symbol, and the generating unit is specifically configured to: the sending end equipment generates the first training sequence and a second training sequence which is the same as the first training sequence according to the first pilot frequency symbol and the second pilot frequency symbol, wherein the second training sequence is used for frequency offset estimation;
the sending unit is specifically configured to: the sending end device sends the first target signal including the first training sequence and the second training sequence to the receiving end device.
11. A receiving-end device, comprising:
a receiving unit, configured to receive a second target signal including a third training sequence; wherein the second target signal is sent by the sending end equipment and comprises a first training sequenceThe first target signal is transmitted and then received by the receiving end equipment; the first training sequence is generated according to at least one pilot symbol, each of which comprises M subcarriers, wherein a first subcarrier of the M subcarriers carries pilot data, and M ═ 2nN is a positive integer greater than or equal to 1; carrying pilot frequency data by every 4N subcarriers from the first subcarrier; n is an integer greater than or equal to 0, wherein the first training sequence is:
Figure FDA0002420642610000052
wherein n is0Is the time instant of the first pilot symbol,
Figure FDA0002420642610000053
is pilot data, the first pilot symbol comprises a total of M subcarriers, M being numbered 0,1, …, M-1 respectively00,1, …, M/4N-1, the first pilot symbol being any one of the at least one pilot symbol, g (K) being a filter, a truncation length KM, where K is an overlap factor of the filter, K being a positive integer greater than or equal to 1; the training sequence relates to
Figure FDA0002420642610000061
Conjugate symmetry, i.e.
Figure FDA0002420642610000062
Wherein, k is 0,1, M/2-1;
a first estimating unit, configured to determine a time offset value of the second target signal by using a time domain parameter of the third training sequence according to a conjugate symmetry characteristic of the third training sequence;
and the second estimation unit is used for carrying out frequency offset estimation on the second target signal.
12. The receiving-end device of claim 11, wherein the receiving-end device is configured to receive the data packet from the receiving-end deviceThe first estimating unit is specifically configured to calculate a time offset value of the second target signal r (k) by using the following relation
Figure FDA0002420642610000063
Figure FDA0002420642610000064
Figure FDA0002420642610000065
Figure FDA0002420642610000066
13. The receiving end device of claim 12, further comprising a compensation unit for utilizing the time offset value
Figure FDA0002420642610000067
Performing time offset compensation on the second target signal; performing frequency offset compensation on the second target signal after time offset compensation by using any frequency offset value in the frequency offset range;
the second estimating unit is specifically configured to calculate a correlation between the second target signal after frequency offset compensation and a local training sequence, and determine a frequency offset value that maximizes the correlation between the second target signal after frequency offset compensation and the local training sequence as the frequency offset value of the second target signal.
14. The receiving end device according to claim 12 or 13, wherein a fourth training sequence is further included in the second target signal; the fourth training sequence is a sequence that is received by the receiving end device after a second training sequence generated by the sending end device is transmitted, and the second training sequence is the same as the first training sequence;
the second estimating unit is specifically configured to calculate correlation information between the third training sequence and the fourth training sequence, and determine a frequency offset value of the second target signal according to the correlation information.
CN201610380679.0A 2016-05-31 2016-05-31 Method and device for pilot frequency transmission Expired - Fee Related CN107453853B (en)

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