CN107294882A - Channel estimation methods and device - Google Patents

Channel estimation methods and device Download PDF

Info

Publication number
CN107294882A
CN107294882A CN201610216412.8A CN201610216412A CN107294882A CN 107294882 A CN107294882 A CN 107294882A CN 201610216412 A CN201610216412 A CN 201610216412A CN 107294882 A CN107294882 A CN 107294882A
Authority
CN
China
Prior art keywords
midamble code
channel
signal
las
channel estimation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201610216412.8A
Other languages
Chinese (zh)
Other versions
CN107294882B (en
Inventor
不公告发明人
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xinyi avatar Intelligent Technology Co., Ltd
Original Assignee
Shenzhen Super Data Link Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shenzhen Super Data Link Technology Ltd filed Critical Shenzhen Super Data Link Technology Ltd
Priority to CN201610216412.8A priority Critical patent/CN107294882B/en
Priority to PCT/CN2017/079579 priority patent/WO2017174002A1/en
Publication of CN107294882A publication Critical patent/CN107294882A/en
Application granted granted Critical
Publication of CN107294882B publication Critical patent/CN107294882B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
    • 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
    • H04L25/0202—Channel estimation
    • H04L25/0212—Channel estimation of impulse response
    • 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
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/0022—PN, e.g. Kronecker
    • H04J13/0025—M-sequences
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/0055—ZCZ [zero correlation zone]
    • H04J13/007—LAS, i.e. LA, LS and LAS codes

Abstract

The invention provides a kind of channel estimation methods, including：Signal, including midamble code and data are received, wherein midamble code frequency range is more than power spectral density of the power spectral density less than data of data bandwidth and midamble code, and the midamble code and the data are at least partially overlappingly sent in frequency and/or on the time；Detection receives the midamble code in signal；The midamble code received in signal and local midamble code are performed into auto-correlation computation；And carry out channel estimation from the result of the auto-correlation computation.Present invention also offers a kind of channel estimating apparatus, including：Signal receiving unit；Synchronization unit；And autocorrelation calculation unit, the midamble code received in signal and local midamble code are performed auto-correlation computation by it, and carry out channel estimation from the result of the auto-correlation computation.The success rate that system subsequently decodes process can be improved by implementing the present invention, reduce error rate of system.

Description

Channel estimation methods and device
Technical field
The present invention relates generally to wireless communication system, more particularly to a kind of channel estimation methods and device.
Background technology
Cordless communication network be widely deployed with provide such as voice, video, grouped data, information receiving, The various communication services such as broadcast.These wireless networks can be propped up by sharing available Internet resources Hold the multi-access network of multiple users.The example of this kind of multi-access network include CDMA (CDMA) network, Time division multiple acess (TDMA) network, frequency division multiple access (FDMA) network, orthogonal FDMA (OFDMA) Network and Single Carrier Frequency Division Multiple Access (SC-FDMA) network.
With global mobile communication constantly enhanced demand, the frequency resource of radio communication is more nervous.Therefore, Except the above-mentioned conventional highfrequency spectrum utilization rate based on TDM (time division multiplexing), FDM (frequency division multiplexing) Outside wireless communication system, it is also proposed that there is the more radical communication plan of more high usage for frequency spectrum.
System is exactly for overlapped time division multiplexing (Overlapped Time Division Multiplexing, OvTDM) Such a scheme for improving system spectral efficiency.In OvTDM systems, not only need not between symbol It is mutually isolated, and can have very strong mutual overlapping.In other words, OvTDM systems are by artificially drawing Enter the overlapping between symbol, transmit data sequence in time-domain parallel using multiple symbols, frequency spectrum greatly improved Utilization rate.
Overlapping frequency division multiplexing (Overlapped Frequency Division Multiplexing, OvFDM) system It is the scheme that another improves system spectral efficiency., can between sub-carrier band in OvFDM systems It is more stronger than orthogonal frequency division multiplex OFDM overlapping to have.Pass through weight higher between each sub-band in frequency domain Folded degree, further increases the availability of frequency spectrum on the basis of ofdm system.
Although there is corresponding reception demodulation scheme to exclude letter for above-mentioned OvTDM systems and OvFDM systems Number time domain or frequency domain overlapping brought interference, but the availability of frequency spectrum is greatly improved still to signal Reception propose requirements at the higher level.
Therefore, OvTDM systems and OvFDM systems need the network insertion scheme of higher performance.It is existing Communication system can not meet demand by the way of m-sequence does channel estimation.
The content of the invention
The brief overview of one or more aspects given below is to provide to the basic comprehension in terms of these.This is general The extensive overview of the not all aspect contemplated is stated, and is both not intended to identify the key of all aspects Or the decisive key element also non-scope attempted to define in terms of any or all.Its unique purpose is will be with simplification Some concepts that form provides one or more aspects think the sequence of more detailed description given later.
It is an object of the present invention to channel estimation be done using m-sequence for existing communication system, due to m It is zero everywhere that the autocorrelation performance of sequence, which is not, and the channel model and actual channel deviation estimated is larger, makes Into the higher defect of error rate of system there is provided a kind of channel estimation methods and device, to solve the above problems.
In one embodiment of the invention there is provided a kind of channel estimation methods, including：Receive signal, Including midamble code and data, wherein midamble code frequency range is more than data bandwidth and the power spectral density of midamble code is less than The power spectral density of data, and the midamble code and the data be frequency and/or on the time at least partly weigh Send foldedly；Detection receives the midamble code in signal；By the midamble code and local midamble code that receive in signal Perform auto-correlation computation；And carry out channel estimation from the result of the auto-correlation computation.
In a preferred embodiment, the midamble code received in signal includes receiving the midamble code of signal first With the reception midamble code of signal second, the local midamble code includes local first midamble code and local second training Code, performing auto-correlation computation includes：The midamble code of signal first will be received and perform first with local first midamble code Auto-correlation computation is to carry out the first channel estimation；The midamble code of signal second will be received to hold with local second midamble code The auto-correlation computation of row second is to carry out second channel estimation；And the result and second of the first channel estimation of combination The result of channel estimation.
In a preferred embodiment, the result of the first channel estimation of combination and the result bag of second channel estimation The result for including result and the second channel estimation to the first channel estimation is averaged.
In a preferred embodiment, the midamble code include m-sequence, Golomb codes, CAN codes, Or LAS codes.
In a preferred embodiment, the midamble code frequency range be more than 5 times of data bandwidth, 10 times, 15 Times or more.
In a preferred embodiment, the signal that receives includes the multipath signal via multi-path channel transmission, Methods described further comprises：Local midamble code is shifted for every multipath channel；And will receive Midamble code in signal performs auto-correlation computation to enter with the local midamble code for every multipath channel displacement The channel estimation of every multipath channel of row.
In a preferred embodiment, the channel estimation methods also include：It incite somebody to action this for every multipath channel The midamble code of ground first is shifted；The midamble code of signal first and the sheet for every multipath channel displacement will be received The midamble code of ground first performs auto-correlation computation to carry out the first channel estimation of every multipath channel；For every Multipath channel is shifted local second midamble code；The midamble code of signal second will be received with being directed to every multipath Local second midamble code of channel displacement performs auto-correlation computation to carry out the second channel of every multipath channel Estimation；And first channel estimation and second channel of every multipath channel of combination are estimated to obtain every multipath The channel estimation of channel.
In a preferred embodiment, local midamble code is carried out into displacement for every multipath channel includes being directed to Local midamble code is moved a position by every multipath channel.
In a preferred embodiment, the midamble code that detection receives in signal will be received by using sliding window method Signal and local code perform auto-correlation computation and detect autocorrelation peak to carry out.
In a preferred embodiment, the midamble code includes training sequence [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LNIn LAS long codes, wherein [0]SNIt is SN for length 0 sequence, [Xlas]SNThe LAS short codes for being SN for length, [Xlas]LNThe LAS for being LN for length Long code, the LAS long codes are used to carry out channel estimation.
In another embodiment of the present invention there is provided a kind of channel estimating apparatus, including：Signal is received Unit, for receiving signal, the signal of reception includes midamble code and data, and wherein midamble code frequency range is more than number It is less than the power spectral density of data, and the midamble code and the number according to the power spectral density of frequency range and midamble code At least partially overlappingly sent according in frequency and/or on the time；Synchronization unit, it, which is detected, receives in signal Midamble code；And autocorrelation calculation unit, it performs the midamble code received in signal and local midamble code Auto-correlation computation, and carry out channel estimation from the result of the auto-correlation computation.
In a preferred embodiment, the midamble code received in signal includes receiving the midamble code of signal first With the reception midamble code of signal second, the local midamble code includes local first midamble code and local second training Code；The autocorrelation calculation unit is configured to hold the reception midamble code of signal first with local first midamble code The auto-correlation computation of row first is to carry out the first channel estimation and will receive the midamble code of signal second and local the Two midamble codes perform the second auto-correlation computation to carry out second channel estimation, wherein the channel estimating apparatus is also Including assembled unit, for combining the result of the first channel estimation and the result of second channel estimation.
In a preferred embodiment, the assembled unit combines the result and second channel of the first channel estimation The result of estimation includes result of the assembled unit to result and the second channel estimation of the first channel estimation It is averaged.
In a preferred embodiment, the midamble code include m-sequence, Golomb codes, CAN codes, Or LAS codes.
In a preferred embodiment, the midamble code frequency range be more than 5 times of data bandwidth, 10 times, 15 Times or more.
In a preferred embodiment, the signal that receives includes the multipath signal via multi-path channel transmission, Described device further comprises：Shift unit, it is shifted local midamble code for every multipath channel, Wherein described autocorrelation calculation unit shifts the midamble code received in signal with being directed to every multipath channel Local midamble code performs auto-correlation computation to carry out the channel estimation of every multipath channel.
In a preferred embodiment, the shift unit is configured to local for every multipath channel One midamble code is shifted, is shifted local second midamble code for every multipath channel；It is described from phase Close computing unit be configured to by receive the midamble code of signal first with for every multipath channel shift it is local First midamble code performs auto-correlation computation to carry out the first channel estimation of every multipath channel and by receiving believe Number the second midamble code and local second midamble code for every multipath channel displacement perform auto-correlation computation with Carry out the second channel estimation of every multipath channel；And the assembled unit combines the of every multipath channel One channel estimation and second channel estimation.
In a preferred embodiment, the shift unit is carried out local midamble code for every multipath channel Displacement includes the shift unit and local midamble code is moved into a position for every multipath channel.
In a preferred embodiment, the midamble code that synchronization unit detection is received in signal be by using Sliding window method will receive signal and local code and perform auto-correlation computation and detect autocorrelation peak to carry out.
In a preferred embodiment, the midamble code includes training sequence [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LNIn LAS long codes, wherein [0]SNIt is SN for length 0 sequence, [Xlas]SNThe LAS short codes for being SN for length, [Xlas]LNThe LAS for being LN for length Long code, the LAS long codes are used to carry out channel estimation.
The present invention has following beneficial effect：The present invention is by design LAS code training sequences, utilizing It is zero everywhere beyond preferable impulse function, origin that LAS codes auto-correlation function is in origin, and cross-correlation letter Number is zero characteristic everywhere, and channel estimation is done using the LAS codes in signal reception processing.So as to realize When doing channel estimation using LAS codes, the deviation of channel estimation model and ideal communication channel model is reduced, is carried High system subsequently decodes the success rate of process, reduces error rate of system.
Brief description of the drawings
After the detailed description of embodiment of the disclosure is read in conjunction with the following drawings, this better understood when The features described above and advantage of invention.In the accompanying drawings, each component is not necessarily drawn to scale, and with class As the component of correlation properties or feature may have same or like reference.
Fig. 1 shows the block diagram of the transmitting terminal modulation module of OvTDM systems.
Fig. 2 shows the block diagram of the signal pre-processing module of the receiving terminal of OvTDM systems.
Fig. 3 shows the block diagram of the receiving terminal sequence detection module of OvTDM systems.
Fig. 4 shows the modulation module block diagram of the transmitting terminal of OvFDM systems.
Fig. 5 shows the block diagram of the signal pre-processing module of the receiving terminal of OvFDM systems.
Fig. 6 shows the block diagram of the signal detection module of the receiving terminal of OvFDM systems.
Fig. 7 shows the autocorrelation performance of M sequence.
Fig. 8 shows the autocorrelation performance of LAS codes.
Fig. 9 shows the distribution map of the autocorrelation result in the presence of two peak values.
Figure 10 shows the schematic diagram for detecting the training sequence under two peak value situations.
Figure 11 shows the block diagram of the time synchronization unit of receiving terminal according to an aspect of the present invention.
Figure 12 shows the flow chart of time synchronization method according to an aspect of the present invention.
Figure 13 shows the block diagram of carrier synchronization unit.
Figure 14 shows the flow chart of the carrier synchronization method according to an embodiment.
Figure 15 shows the flow chart of the carrier synchronization method according to another embodiment.
Figure 16 shows the block diagram of the channel estimating apparatus of receiving terminal according to an aspect of the present invention.
Figure 17 shows the flow chart of channel estimation methods according to an aspect of the present invention.
Figure 18 shows being shifted local midamble code for multipath channel according to an aspect of the present invention Schematic diagram.
Figure 19 shows training sequence according to an aspect of the present invention and the frequency range and power spectral density of data Graph of a relation.
Figure 20 shows that the frequency range and power spectral density of two carrier signals according to an aspect of the present invention are closed System's figure.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.Note, below in conjunction with accompanying drawing and The aspects of specific embodiment description is only exemplary, and is understood not to protection scope of the present invention Carry out any limitation.
Except applying in OvTDM and OvFDM systems, all technologies described herein also can be extensive Applied in actual GSM, such as TD-LTE, TD-SCDMA system also can extensive use Communicated in satellite communication, microwave horizon communication, scatter communication, atmosphere optic communication, infrared communication with aquatic Etc. in any wireless communication system.Term " network " and " system " are often used interchangeably.
Mobile communication continue to develop and new business emerge in an endless stream message transmission rate is proposed it is more next Higher requirement, and the frequency resource of mobile communication is extremely limited, it is how real using limited frequency resource The high-speed transfer of existing data turns into the major issue that current mobile communication technology faces
Above-mentioned OvTDM and OvFDM systems are exactly this can to greatly improve the solution party of the availability of frequency spectrum Case.OvTDM systems are briefly described below sends and receives process.
OvTDM systems are using multiple symbols in time-domain transmitting data in parallel sequence.Form many in transmitting terminal Individual symbol transmission signal overlapped in time-domain, in receiving terminal according to transmission data sequence and transmission number According to the one-to-one relationship between sequence time waveform, docking is collected mail and presses data sequence in number progress time-domain Detection.OvTDM systems actively using these it is overlapping be allowed to produce coding bound relation, so as to significantly carry The high spectrum efficiency of system.
Fig. 1 shows the block diagram of the transmitting terminal modulation module of OvTDM systems.Transmitting terminal modulation module 100 It may include digital waveform generating unit 110, shifting deposit unit 120, multiplication unit 130 and adder unit 140。
First, first tune that generation sends signal is designed in a digital manner by digital waveform generating unit 110 The envelope waveform h (t) is carried out special time shifting by signal envelope waveform h (t) processed, shifting deposit unit 120 Position, forms the envelope waveform h (t-i × Δ T) of other each moment modulated signal, and multiplication unit 130 is by institute The parallel symbol x to be sentiIt is multiplied with the envelope waveform h (t-i × Δ T) at corresponding moment, when obtaining each Signal waveform x to be sent after quarter is modulatedih(t-i×ΔT).Adder unit 140 by formed each Waveform to be sent is overlapped, and forms transmission signal waveform.
The receiving terminal of OvTDM systems is broadly divided into signal pre-processing module 200 and sequence detection module 300.Fig. 2 shows the block diagram of the signal pre-processing module 200 of the receiving terminal of OvTDM systems.Letter Number pretreatment module, which is used to aiding in forming the synchronous of each frame in, receives digital signal sequences, as illustrated, The signal pre-processing module may include synchronization unit 210, channel estimating unit 220 and digitized processing Unit 230.
Synchronization unit 210 is used to dock the collection of letters number in time domain formation sign synchronization, to keep same with system Step state, mainly includes Timing Synchronization and carrier synchronization.Rear channel estimating unit 220 is synchronously completed to dock Channel estimation is done in the collection of letters number, for estimating the parameter of actual transmission channel.Digitized processing unit 230 is used Processing is digitized in the reception signal to each frame in, so that forming suitable Sequence Detection part carries out sequence Arrange the reception digital signal sequences of detection.
After pre-processing, the docking collection of letters number a Sequence Detection, docking can be carried out in sequence detection module 300 The waveform received is cut according to waveform transmission time interval and according to certain decoding algorithm to the ripple after cutting Shape enters row decoding.Fig. 3 shows the block diagram of the receiving terminal sequence detection module of OvTDM systems.As schemed Show, sequence detection module 300 may include analysis memory cell 310, comparing unit 320 and retain road Footpath memory cell and Euclidean distance memory cell 330.In detection process, analysis memory cell is made The complex convolution encoding model and trellis structure of OvTDM systems, and list whole states of OvTDM systems, And store.Trellis structure of the comparing unit in analysis memory cell, is searched out with receiving data signal minimum The path of Euclidean distance, and surviving path memory cell and Euclidean distance memory cell are then respectively used to storage ratio The surviving path and Euclidean distance or weighted euclidean distance exported compared with unit.Surviving path memory cell and Euclidean Need respectively to prepare one for each stable state apart from memory cell.Surviving path memory cell length can be with Preferably 4K~5K.Euclidean distance memory cell is preferably only to store relative distance.
Fig. 4 shows the modulation module block diagram of the transmitting terminal of OvFDM systems.The OvFDM of transmitting terminal is adjusted Molding block may include modulation carrier spectrum generation unit 410, carrier spectrum shift unit 420, multiplication unit 430th, adder unit 440 and Fourier inverse transformation unit 450.
First, the envelope frequency spectrum signal of one subcarrier of generation is designed by modulation carrier spectrum generation unit 410 H (f), carrier spectrum shift unit 420 by the envelope frequency spectrum signal H (f) successively frequency displacement specific carriers frequency Interval delta B is composed, the envelope frequency spectrum signal of next subcarrier is drawn, and by the bag of next subcarrier Network spectrum signal frequency displacement Δ B, goes down to obtain successively the spectrum waveform for all subcarriers that spectrum intervals is Δ B H(f-i×ΔB)。
Multiplication unit 430 is by the symbol X for the multidiameter delay to be sentiIt is corresponding with generation each respectively Individual subcarrier spectrum waveform H (f-i × Δ B) is multiplied, and obtains modulation of the multichannel Jing Guo corresponding subcarrier-modulated Signal spectrum XiH(f-i×ΔB)。
The multiplexing signal spectrum formed is overlapped by adder unit 440, forms complex modulated signal Frequency spectrumFinally, by Fourier inverse transformation unit 450 by the polyphony of generation The frequency spectrum of signal processed carries out discrete Fourier inverse transformation, ultimately forms the complex modulated signal of time domain Signal(t)TX=ifft (S (f)).
The receiving terminal of OvFDM systems is broadly divided into signal pre-processing module 500 and signal detection module 600.Fig. 5 shows the block diagram of the signal pre-processing module of the receiving terminal of OvFDM systems.As schemed Show, pretreatment module may include synchronization unit 510, channel estimating unit 520 and digitized processing list Member 530.
Synchronization unit 510 is used to dock the collection of letters number in time domain formation sign synchronization, to keep same with system Step state, mainly includes Timing Synchronization and carrier synchronization.Rear channel estimating unit 520 is synchronously completed to dock Channel estimation is done in the collection of letters number, for estimating the parameter of actual transmission channel.Digitized processing unit 530 is used In the interval reception signal of each symbol time is sampled and quantified, it is allowed to be changed into digital signal sequences.
After pre-processing, the collection of letters number can be docked in signal detection module 600 to be detected.Fig. 6 is shown The block diagram of the signal detection module 600 of the receiving terminal of OvFDM systems.As illustrated, signal detection Module 600 may include Fourier transformation unit 610, frequency segmentation unit 620, convolutional encoding unit 630, And data detecting unit 640.Fourier transformation unit 610 is used to turn the time-domain signal by pretreatment Change frequency domain signal into, i.e., Fourier transform is carried out to the interval reception digital signal sequences of each time symbol To form the actual receipt signal frequency spectrum that each time symbol is interval.Frequency segmentation unit 620 is used for each The interval actual receipt signal frequency spectrum of time symbol is segmented in frequency domain with spectrum intervals Δ B, forms actual receive Signal subsection frequency spectrum.Convolutional encoding unit 630 is used for the data symbol sequence for forming receipt signal frequency spectrum with sending One-to-one relationship between row.Data detecting unit 640 is used for according to the formation of convolutional encoding unit one by one Corresponding relation, detects data symbol sequence.
It is described above the processing procedure for sending and receiving end of OvTDM systems and OvFDM systems.To the greatest extent Manage above-mentioned OvTDM systems and OvFDM systems have it is corresponding receive demodulation scheme exclude signal when Domain or overlapping the brought interference of frequency domain, but the reception greatly improved still to signal of the availability of frequency spectrum Propose requirements at the higher level.
Project training sequence is required in general communication system, its act on mainly after signal is received by Processing, Timing Synchronization, carrier synchronization and channel estimation can be realized simultaneously.Timing Synchronization, carrier synchronization and letter Road estimation is three most important links that receiving terminal is properly received.Therefore, the design of training symbol is most important, Communication system especially for this superelevation spectrum efficiency of OvTDM and OvFDM systems is especially true. If either step error is larger in these three steps, the influence to whole system will be very big, and follow-up translates Code process is also just nonsensical.
Current communication system is training sequence frequently with M sequence, because M sequence auto-correlation and cross-correlation are special Property is poor, causes system synchronization procedure success rate low, network insertion is slow.Fig. 7 shows oneself of M sequence Correlation properties, as we can see from the figure its autocorrelation performance separated in time pulse can all occur, it is from phase It is not fine to close characteristic.Therefore it is poor to the synchronization accuracy of time and frequency in signal processing, drop The success rate and access speed of low user access network, make Consumer's Experience be deteriorated.
According to an aspect of the present invention, set in OvTDM systems and OvFDM systems using LAS codes Count training sequence.It has been investigated that, there is LAS codes auto-correlation function to be preferable impulse function in origin, It is zero everywhere beyond origin, and cross-correlation function is zero characteristic everywhere.This is pole for training sequence Its favourable attribute.
LAS (Large Area Synchronized, large area synchronous) code be by a series of pulses and 0 long value pulse spacing composition, can be expressed as (N, K, L), wherein N represents pulse number, K tables Show the most short gap length between pulse, L represents code length.Pulse is generated by complete complementary orthogonal, and it is special Point is preferable impulse function in origin for auto-correlation function, is zero everywhere beyond origin, and cross-correlation function It is zero everywhere.It is applied to using this feature of LAS codes in OvTDM systems and OvFDM systems, it is right There is preferable performance improvement in the synchronous success rate and access speed of whole system.
The generation method of LAS codes is introduced briefly below.
Complete complementary orthogonal has a duality relation, generation method be according to most short basic mutual-complementing code solve with Complete orthogonal complement the most short basic mutual-complementing code of another pair.In present case with basic short code +++-generated Standby complementary orthogonal, generating process is as follows：
C0=[1 1], are corresponded to ++, S0=[1-1], correspond to+-, according to C0And S0Obtain it respectively Mutual-complementing code C1And S1。C1For to S0Negate and obtain, S1For to C0Negating and asking to arrive, generation in matlab Code table is shown as：
C1=fliplr (S0), S1=-1*conj (fliplr (C0)).Wherein fliplr for pair Matrix carries out the function overturn along vertical axis or so, and conj is to seek complex conjugate function.
C is tried to achieve accordingly1=[- 1 1], S1=[- 1-1], by C0C1The new mutual-complementing code of combination producing is C0'=[1 1 - 1 1], S0'=[1-1-1-1], now the length of each mutual-complementing code extends to 4 by 2.
Here the length L of mutual-complementing code can be designedN(LNPower side for 2), i.e. CnAnd SnLength point Wei not LN/2.Using the above method, the LAS codes of generation are iterated, its length is extended for LN, Iterations is log2LN- 2, the mutual-complementing code ultimately generated is Cn、Sn。
By this to mutual-complementing code and null sequence combination producing LAS codes, representation is：Las=[Cn L0 Sn], Wherein L0The number of expression 0, i.e. CnAnd SnBetween most short gap length, the LAS code lengths ultimately generated Degree is expressed as L=LN+L0。
Fig. 8 shows the autocorrelation performance of LAS codes.
According to an aspect of the present invention, LAS codes are employed and carry out project training sequence.
For the purposes of Timing Synchronization, training sequence includes at least one LAS code.Because LAS short codes exist Still there is preferable synchronous effect in the case that frequency deviation is larger, therefore, more preferably, training sequence includes at least one Individual LAS short codes, with [Xlas]SNRepresent, the length of the wherein LAS short codes is designated as SN, its complementary code length L is expressed as with null sequence lengthShort-N、LShort -0, SN=LShort-N+LShort -0。
In order to further optimize the autocorrelation performance of LAS codes, it may also include before the LAS short codes with being somebody's turn to do One null sequence of LAS short code equal lengths, with [0]SNRepresent.
In specific embodiment, training sequence may include two identical LAS short codes, so wherein one In the case that individual LAS short codes can be used for Timing Synchronization, LAS can also be constituted with another LAS short codes Short code pair, for carrier synchronization.
For the purposes of carrier synchronization, training sequence may include at least one pair of identical LAS codes.Due to LAS short codes still have preferable synchronous effect in the case where frequency deviation is larger, therefore, more preferably, training sequence Including at least one pair of identical LAS short codes.
More preferably, carrier synchronization can be divided into the thick synchronous and carrier wave of two stages, i.e. carrier wave carefully synchronously.Therefore, Training sequence may include at least two pairs LAS codes.More preferably, a pair of LAS codes can be identical LAS short codes Slightly synchronous for carrier wave, another pair LAS codes can be identical LAS long codes, carefully same for carrier wave Step.LAS long codes can use [Xlas]LNRepresent, the length of the wherein LAS long codes is designated as LN, its mutual-complementing code Long and null sequence length is expressed as LLong-N、LLong -0, LN=LLong-N+LLong -0。
In order to further optimize the cross correlation of LAS codes, may also include before each LAS short codes with One null sequence of LAS short code equal lengths, with [0]SNRepresent.
For the purposes of channel estimation, training sequence may include at least one LAS code, such as one LAS long codes, or, two LAS long codes are may also comprise, are done twice for the two long LAS codes Channel estimation, so as to improve the success rate of channel estimation.
As particular example, L can be designedLong-N=256, LLong -0=16；LShort-N=16, LShort -0=8.Certainly, Here LAS long codes and the length of LAS short codes is only shown as example, may be designed as other length Degree.
It is a kind of while meeting Timing Synchronization, carrier synchronization and channel estimation as preferably embodiment LAS code training sequences may be designed as：[0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LN.It is real herein Apply in example, first LAS code is short code, and Timing Synchronization can be achieved, and LAS short codes are larger still in frequency deviation The synchronous effect having had.First and second LAS short code can be used for carrier wave slightly synchronous, short code it is good Place is can to handle larger frequency deviation.Most latter two LAS code is long code, available for thin correcting frequency deviation and Channel estimation.
Project training sequence frequency range
Design symbols structure includes training sequence TSC (traning sequence code) and data in the system (data).The design of training symbol is most important, and the timing, synchronization, channel that have impact on whole system are estimated Three most important links are counted, if either step error is larger in these three steps, to the shadow of whole system Sound will be very big, and follow-up decoding process is also just nonsensical.
The design process of training sequence frequency range is complex, when frequency range is shorter its corresponding power spectral density compared with Greatly, the reception and transmission of data can be influenceed when there is multiple carrier waves in system, corresponding work(when frequency range is excessive Rate spectrum density is too small, and the sensitivity requirement of transmitter and receiver to system is high.
It is general using training sequence and the frequency range identical method of data, its correspondence in existing communication system Power spectral density it is identical, and due in General System frequency range it is all shorter, therefore corresponding to time domain send the time Longer, influence signal is synchronous, channel estimation process time course, and the follow-up decoding process stand-by period is also elongated, Reduce the transmission rate of system.Further, since the training sequence transmission time is longer, therefore enter to signal During row sampling, its sample rate is relatively low, and temporal resolution is not fine enough, influences the deviation of channel estimation.
The present invention is expanded to training sequence in broad frequency band by spreading code so that training sequence frequency range is long-range In data bandwidth (for example, 5 times, 10 times or more), its training sequence, the frequency range and power spectrum of data Density relationship figure is as shown in Figure 19.Because the transmit power of training sequence and data need to be consistent, by It can be seen from the figure that, after the frequency range of training sequence broadens, its corresponding power spectral density consequently also can be significantly Degree reduction, is very low for data power spectral density.
The system can use all available spreading codes, including m-sequence, Golomb codes, CAN (Cyclic Algorithm New) and LAS codes etc..We are with complete complementary orthogonal property in the system Exemplified by LAS codes, the processing procedure of Timing Synchronization, carrier synchronization and channel estimation is introduced.The characteristics of LAS codes Be auto-correlation function be in origin be zero everywhere beyond preferable impulse function, origin, and at cross-correlation function Place be the autocorrelation performance of zero, LAS codes as shown in Figure 8.Therefore also will not phase when training sequence is overlapping Mutually interfere.So design can improve the availability of frequency spectrum and transmission rate of system.
By formulaUnderstand, when frequency domain frequency range is bigger, its correspondence is smaller in the time of time domain, that is, exists Training sequence can be just completed in the shorter time sends and receives process.Process is received in signal, for The data of same length, when 330 receiving between shorten, the sample rate of signal can be improved so that time resolution Rate is finer.The accuracy of temporal resolution is improved in channel estimation process so that channel estimation results are more smart Really.
On the one hand, because the power spectral density of training sequence is extremely low, shadow hardly is produced to data-signal Ring, therefore training sequence and data can be superimposed in the same time and send.Sent simultaneously when there are two carrier signals During data, its structural map as shown in Figure 20, it can be seen that the reality that two carrier waves are carried There is protection band in the middle of data, overlapping also will not will not mutually interfere；And the frequency range and reality of training sequence Data have overlapping, because training sequence power spectral density is very low, therefore real data will not be interfered； Further, different training sequences can be distinguish between with different spreading codes, do not result in and obscure.Training sequence Specific frequency and time resource are not monopolized, the availability of frequency spectrum and transmission rate of system is improved.
In one embodiment, can be used in the system the LAS codes with complete complementary orthogonal property for Training sequence, it is zero everywhere beyond preferable impulse function, origin that its feature is in origin for auto-correlation function, And cross-correlation function is zero everywhere, the auto-correlation and cross correlation of LAS codes are as shown in Figure 5.Therefore work as Also will not mutually it be interfered when training sequence is overlapping.So design can improve system the availability of frequency spectrum and Transmission rate.
Timing synchronization procedure
Receiver receives signal, it is necessary to first keep synchronous with communication system, including Timing Synchronization and carrier synchronization. The principle of Timing Synchronization is, by matched filtering method, will directly to receive signal and asked with local LAS codes from phase Computing is closed, autocorrelation peak is obtained.The position of training symbol is found according to certain method from correlation peak. The position for finding training symbol has also determined that the original position of present frame, that is, completes reception signal and system Time synchronized, timing synchronization procedure terminates.
As previously described, because the auto-correlation and cross correlation of LAS codes are all relatively good, LAS codes are used for Project training symbol.Thus, when calculating the related operation for receiving signal and LAS codes, peak value size point Cloth differs greatly, by reasonably setting threshold value, can accurately find very much the original position of LAS codes, Timing accuracy is higher.
Specifically when finding the correlation peak of LAS codes, according to training symbol structure, suitable signal is taken Length is received, using sliding window method auto-correlation computation mode, signal will be received to local LAS codes and seek related fortune Calculate and find autocorrelation peak to determine the position of LAS codes.It can ensure for example, signal here receives length At least covering has LAS codes, to guarantee to detect peak value.
So-called sliding window method auto-correlation computation, is that the docking collection of letters number is made by length of window of the length of LAS codes Take window to handle, this segment signal in current window and local LAS codes are made into related operation, so as to obtain One autocorrelation result.Then, window is slided backward, then docks a collection of letters number progress and take window, by current window This intraoral segment signal remakes related operation with local LAS codes, so as to obtain a correlated results again. In this way, continuous sliding window, until all having carried out related operation to the signal received.From calculating The whole autocorrelation results drawn, by setting threshold value, i.e., more than threshold value autocorrelation result as peak value, Find the position of LAS codes.
In one example, LAS code is only included in training sequence, such as one LAS short code, because Short code still has preferable synchronous effect in the case where frequency deviation is larger.In this case, it is possible to by the LAS The length of short code is collected mail as length of window docking number takes window to handle, by this segment signal in current window and Local LAS short codes make related operation, so as to obtain an autocorrelation result.Then, by window backward Slide, then dock the collection of letters number progresss and take window, by this segment signal in current window and local LAS codes again Make related operation, so as to obtain a correlated results again.In this way, continuous sliding window, until docking The signal received has all carried out related operation.From the whole autocorrelation results calculated, by setting threshold Value, i.e., more than threshold value autocorrelation result as peak value, find the position of LAS codes.
In the case of multipath channel, it is possible to which the amplitude for several footpaths below occur exceeds the width in first footpath Value, it should which choosing exceedes first peak point of threshold value, and is not necessarily global maximum.Fig. 9 shows fixed When synchronous autocorrelation result distribution map.Assuming that threshold value is 100, as shown in figure 9, more than threshold value 100 Autocorrelation result have two, but be chosen at the autocorrelation results of 25 positions as the peak value of this computing, So as to regard this as the position of the LAS codes found in 25 position.
In previous preferably training symbol format [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LN's In the case of, there are two LAS short codes in training sequence.Now, above-mentioned sliding window autocorrelation calculation is passed through Method can find out two peak values for exceeding threshold value.Fig. 9 shows the autocorrelation result in the presence of two peak values Distribution map.At this time, it may be necessary to judge which is the peak value in preceding short code, which is in rear short code Peak value.
Figure 10 shows the schematic diagram for detecting the training sequence under two peak value situations.In Fig. 10 Show two training sequences that repetitive cycling is sent.Receive two training sequences of length spans of signal Row, therefore, two peak values finding out may one of them be due to first of next training sequence Caused by LAS short codes.So needing to judge which LAS short code corresponding to each peak value be.
Specifically, if two peak intervals length are 2*SN, then choose first and exceed threshold value Peak value is the original position of first short LAS codes, if both gap lengths are more than 2*SN, second The individual peak value more than threshold value is the original position of first short LAS code.
If there is multipath channel, then two part integrated distribution relevant peaks occur after sliding window, to every portion The relevant peaks divided are compared with threshold value respectively, choose first peak point of threshold value, two parts are completeer Two points for exceeding threshold value will be obtained afterwards, and the position of correspondence LAS codes is determined further according to method as above.
Then it is relatively light one by one after matched filtering in addition, if transmission signal have passed through other band limiting filters Sliding peak, rather than independent point, so needing to choose peak point according to actual band limiting filter.
Figure 11 shows the block diagram of the time synchronization unit of receiving terminal according to an aspect of the present invention.This is determined When synchronization unit can be a part above in association with Fig. 2 and Fig. 5 synchronization unit discussed.
As shown in figure 11, time synchronization unit 1100 may include autocorrelation calculation unit 1110 to hold Row autocorrelation calculation.The autocorrelation calculation unit 1110 can carry out taking window to the signal received, to use Local LAS codes make autocorrelation calculation to the signal in window, and slide the window to carry out next time certainly Correlation computations, until reaching that signal receives length.Time synchronization unit 1100 may also include peak value and judge single Member 1120, judges the position of peak value, to find LAS codes for the correlated results set according to acquisition Original position.Peak value judging unit 1120 can choose suitable threshold value, by more than the auto-correlation knot of threshold value Fruit is used as peak value.
Figure 12 shows the flow chart of time synchronization method according to an aspect of the present invention.As illustrated, This method may include：
Step 1201：The signal received is carried out taking window, to use local LAS codes in window Signal makees autocorrelation calculation, and slides the window to carry out autocorrelation calculation next time, until reaching that signal connects Receive length；And
Step 1202：The position of peak value is judged according to the correlated results set of acquisition, to find LAS codes Original position.
As described above, in the case where there are two LAS short codes, if two peak intervals length are 2*SN, then choose the original position that first peak value for exceeding threshold value is first short LAS codes, if Both gap lengths are that then second exceedes the peak value of threshold value rising for first short LAS codes more than 2*SN Beginning position.
Carrier synchronization process
Receive after signal, it is necessary to first keep synchronous with communication system, including Timing Synchronization and carrier synchronization, The synchronization on signal and system first retention time is received, the original position of LAS codes is obtained by Timing Synchronization, Enter the synchronization of line frequency again.
For carrier synchronization, receiving the training sequence message part of signal includes at least one pair of identical LAS Code.Computing cross-correlation is carried out to the LAS codes repeated, frequency deviation f is obtained.
Assuming that the carrier deviation between receiver and emitter be Δ f, the AD sampling interval be T, then receive When noise signal influence is ignored at end, the signal received is expressed as：
yn=xnej2πΔfnT
The coefficient correlation of former and later two LAS codes is：
Wherein L represents the interval between LAS codes.
From above formula, carrier wave frequency deviation is：
More preferably, training sequence message part may include two pairs of LAS codes, wherein, a pair of identical LAS Code is LAS short codes, it is possible thereby to which it is slightly synchronous first to carry out carrier wave；Include a pair of identical LAS length again in addition Code, it is possible thereby to which it is carefully synchronous to carry out carrier wave.
Due to having been completed Timing Synchronization, the training symbol that can be returned according to Timing Synchronization index is extracted pair The short LAS codes of two parts answered, carrier wave are carried out to short LAS codes slightly synchronously, short code can handle larger frequency Partially, it is Δ f that the frequency deviation value estimated is calculated according to above-mentioned formula1.Then the long LAS of two parts is extracted again Code, the thin correcting frequency deviation of carrier wave is carried out to long LAS codes, and the frequency deviation value estimated is Δ f2, with reference to thick synchronization Frequency deviation, then the frequency deviation of final output be Δ f=Δs f1+Δf2。
With previous preferably training symbol format [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LNFor Example.LN=272, SN=24 are made, training symbol total length is 640.Two short LAS exist respectively (25:48) with (73:96) two positions, long LAS code divisions are not (97:368) with (369：640) Two positions.
Ideally, the original position that Timing Synchronization calculates obtained LAS codes is first short LAS codes Original position, as 25.It is right from signal is received according to this index and the code length LN and SN of long short code That answers extracts corresponding code.
Carrier wave is slightly synchronous
The short LAS codes of two parts are extracted from signal is received, according to formulaConjugation is sought it It is multiplied, obtains coefficient R.Further according to formulaObtain corresponding thick frequency deviation Δ f1, Wherein L represents the interval between two short LAS codes, the L=2*SN=it can be seen from training symbol structure 48。
Thick frequency deviation according to calculating passes through formulaThe docking collection of letters number carries out a frequency offset correction, Obtain the signal after first time frequency offset correction.
The thin frequency offset correction of carrier wave
The docking collection of letters number has carried out thick frequency offset correction in the thick synchronization of carrier wave, obtains receiving signal yn'.Thin frequency deviation Process is from yn' in extract the long LAS codes of two parts, according to formulaConjugation phase is sought it Multiply, obtain coefficient R.Further according to formulaObtain corresponding thin frequency deviation Δ f2, L represents the interval between two long LAS codes, the L=LN=272 it can be seen from training symbol structure.
With reference to thick synchronous frequency deviation, then the frequency deviation of final output is Δ f=Δs f1+Δf2.And according to formula yn"=yn'ej2π(-Δf)nTObtain the signal after the thin correcting frequency deviation of the docking collection of letters number.
By the signal y after frequency offset correction twicen" as input signal to channel estimation process, carrier synchronization mistake Journey terminates.
Figure 13 shows the block diagram of carrier synchronization unit 1300.On the carrier synchronization unit 1300 can be A part of the text with reference to Fig. 2 and Fig. 5 synchronization units discussed.
As illustrated, carrier synchronization unit 1300 may include cross-correlation calculation unit 1310 and frequency correction list Member 1320.Cross-correlation calculation unit 1310 can perform cross-correlation calculation to obtain receiving terminal to a pair of LAS codes The frequency deviation of carrier wave between transmitting terminal.Frequency correction unit 1320 can be according to the frequency deviation of the carrier wave, docking The collection of letters number performs a frequency offset correction.
In one embodiment, the cross-correlation of a pair of LAS short codes can be first carried out in cross-correlation calculation unit 1310 Calculate, to obtain the thick frequency deviation of carrier wave between receiving terminal and transmitting terminal.Frequency correction unit 1320 can first root According to the thick frequency deviation, the docking collection of letters number performs a first frequency offset correction.Cross-correlation calculation unit 1310 is again to from warp A pair of LAS long codes execution cross-correlation calculation that the reception signal of first frequency offset correction is extracted is crossed, to obtain The thin frequency deviation of carrier wave between receiving terminal and transmitting terminal.Frequency correction unit 1320 can further according to the thin frequency deviation and The thick frequency deviation, performs secondary frequency offset correction, to obtain final frequency deviation to the reception signal through first frequency offset correction Signal after correction.
Figure 14 shows the flow chart of the carrier synchronization method according to an embodiment.As illustrated, carrier wave is same One step process may include following steps：
Step 1401：To performing cross-correlation from two LAS codes for receiving signal extraction, to obtain receiving terminal The frequency deviation of carrier wave between transmitting terminal；And
Step 1402：A frequency offset correction is performed based on the frequency deviation docking collection of letters number.
Figure 15 shows the flow chart of the carrier synchronization method according to another embodiment.As illustrated, carrier wave Synchronous method may include following steps：
Step 1501：To performing cross-correlation from two LAS short codes for receiving signal extraction, to be received The thick frequency deviation of carrier wave between end and transmitting terminal；
Step 1502：According to the thick frequency deviation, the docking collection of letters number performs a first frequency offset correction；
Step 1503：A pair of the LAS long codes extracted from the reception signal through first frequency offset correction are performed Cross-correlation calculation, to obtain the thin frequency deviation of carrier wave between receiving terminal and transmitting terminal；And
Step 1504：According to the thin frequency deviation and the thick frequency deviation, the reception signal through first frequency offset correction is held The secondary frequency offset correction of row.
Although the above method is illustrated and is described as a series of actions to simplify explanation, it should be understood that simultaneously Understand, the order that these methods are not acted is limited, because according to one or more embodiments, some actions Can occur in different order and/or with from it is depicted and described herein or herein it is not shown and description but Art personnel, which may be appreciated other actions, concomitantly to be occurred.
Channel estimation process
Channel estimation is used for the transmission characteristic for estimating channel, i.e., channel is to the influence of the signal transmitted.Pass through Using training symbol known to transmitting terminal and receiving terminal both sides, receiving terminal can be according to the known training symbol And the training symbol that receives performs channel estimation.For example, receiving terminal can be to known training Symbol and the training symbol received perform correlation, so that it is determined that the transmission characteristic of channel.Carrying out channel After estimation, receiving terminal can demodulate the unknown data signal received using the channel estimation carried out, To determine the actual data signal of transmitting terminal transmission.
Receive signal and pass through Timing Synchronization, and system hold time synchronization.Then the collection of letters number is docked again does carrier wave Synchronous, carrier synchronization includes thick synchronous and thin synchronous, passes through the synchronous carrier wave for obtaining receiver and transmitter Frequency deviation Δ f, is corrected by carrier wave frequency deviation to the signal of reception, obtains revised reception signal yfix, to yfix Do channel estimation.
The present invention is by the use of LAS codes as training sequence, such as the long LAS codes in training symbol format L-LAS can be used for channel estimation.
Channel estimation is represented by：
Wherein ynRepresent to pass through the revised reception signal of carrier synchronization, i.e. yfix.N represents LAS code lengths. xnRepresent local LAS codes, i.e. xnIt is expressed as most one of latter two long LAS code in training symbol.R0Table Show the quadratic sum of LAS codes, P represents multipath channel number.
Reception signal y of the channel estimator from training symbolfixThe impulse response h (t) of middle estimation channel, then One inverse channel system is constructed according to the h (t) estimated, the data-signal received passes through the inverse channel system The estimation for the signal that channel is fed to transmitting terminal is reduced into afterwards.
It is general to receive signal ynIt can be expressed asenRepresent noise.Substituted into Equation below is obtained after formula expansion：
The auto-correlation of training sequence is represented, is zero by rationally designing auto-correlation coefficient, estimation Channel height is close to real channel, so as to drastically increase the precision of channel estimation.According to the present invention, by The probability for occurring 0 in LAS codes auto-correlation is high, therefore substantially increases channel when carrying out channel estimation The success rate of estimation.
This area typically carries out channel estimation using M sequence.The autocorrelation performance of the M sequence such as institute of accompanying drawing 7 Show, pulse can all occur in its autocorrelation performance separated in time as we can see from the figure, its autocorrelation performance It is not fine, respective channels estimation formulas
InValue is not 0 probability It is very big, therefore the channel model and ideal communication channel model bias that estimate are larger, are handled for follow-up decoding Influence is very big, improves the bit error rate of system.
Contrast LAS code sequences, there is auto-correlation function to be preferable impulse function in origin for it, origin with Outer is zero everywhere, and cross-correlation function is the characteristics of be zero everywhere, therefore when doing channel estimation, actual estimated The channel model and ideal model deviation very little gone out, reduces the bit error rate of system, systematic function is obtained Improve well.
According to the present invention, because long LAS codes have two in training symbol, therefore channel estimation process can To be realized using the long LAS codes of any of which, or it can also be done twice for the two long LAS codes Channel estimation, so as to improve the success rate of channel estimation.
A channel or multipath channel may be present in a communication environment, receiver can determine whether according to environment There is multipath channel.In the case of no multipath channel, i.e. p=0 can be calculated directly according to above formula Channel estimation h.And in the case where there is multipath channel, every multiple paths can be calculated respectively according to above formula Channel estimation value hp, wherein for every multiple paths by local LAS codes xnEnter line displacement, each The deviation in path can be 1.
For example, actual multipath channel can be such as 6.First by local LAS codes according to multipath Number is arranged in 6 row, and the deviation in each row path is 1, and arrangement mode is as shown in Figure 18.
According to training symbol format [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LN, from revise signal yfixIn find corresponding LAS code positions, and extract as yfix-las, common two parts.
By the y extractedfix-lasRespectively with rearrange after 6 multipath channels local LAS codes pass through Formula
After processing, the channel estimation value h of every multiple paths is obtainedp。 Because shared two parts LAS codes can carry out channel estimation, channel can be all obtained per part after treatment Estimate hp, two parts are averaged, the channel estimation value h of every last multiple paths is can obtainp。
Then, can the channel estimation value h based on every multiple pathspSignal estimated matrix received to demodulate Data-signal, so that transmission end signal must be recovered.
Figure 16 shows the block diagram of the channel estimating apparatus 1600 of receiving terminal according to an aspect of the present invention. For completeness, show that channel estimating apparatus 1600 includes the He of signal receiving unit 1602 in Figure 16 Synchronization unit 210.Signal receiving unit 1602 can be any receiver list for being used to receive wireless signal Member, it is via wireless communication channel receiving signal.The detection of synchronization unit 210 receives the LAS codes training in signal Sequence, is described as discussed above concerning Fig. 2,5.Channel estimating apparatus 1600 may also include autocorrelation calculation list Member 1610, it can be the tool of the channel estimating unit 220,520 as discussed above concerning Fig. 2 and Fig. 5 descriptions Body is realized.LAS codes training sequence and local LAS that autocorrelation calculation unit 1610 will be received in signal Code training sequence performs auto-correlation computation, and from the channel estimation of auto-correlation computation result progress wireless channel, As described above.
In the alternative embodiment of twice of channel estimation is done for two long LAS codes, channel estimating apparatus 1600 also alternatively include assembled unit 1620.In this case, autocorrelation calculation unit 1610 can quilt It is configured to that the LAS codes training sequence of signal the first and local first LAS codes training sequence execution first will be received Auto-correlation computation with carry out the first channel estimation and will receive the LAS codes training sequence of signal the 2nd with The LAS codes training sequence of ground the 2nd performs the second auto-correlation computation to carry out second channel estimation.Assembled unit 1620 can combine the first channel estimation and second channel estimation to obtain the channel estimation of wireless channel.
It will be understood by those skilled in the art that a LAS code, two LAS codes, three LAS can be used Code, or more quantity LAS carry out channel estimation.It is more accurate that these channel estimations can be recombined to obtain Channel estimation.Combining may include to sum to each channel estimation, is averaged, takes intermediate value etc., can also base Each channel estimation is handled in other criterions, such as rejecting irrational channel estimation.As above institute State, the first LAS codes training sequence and the 2nd LAS codes training sequence can be each LAS long codes, and Can be mutually the same LAS code training sequences in an alternative embodiment.
In the alternative embodiment that signal is included via the multipath signal of multi-path channel transmission is received, channel estimation Device 1600 may also include shift unit 1630, and local LAS codes are trained sequence by it for every multipath channel Row are shifted.In this case, the LAS codes that autocorrelation calculation unit 1610 will can be received in signal Training sequence and the local LAS codes training sequence execution auto-correlation computation for the displacement of every multipath channel with Carry out the channel estimation of every multipath channel.Displacement may include to be directed to every multipath channel by local LAS codes Training sequence moves position, two positions.
In the case where not carrying out channel estimation with two or more long LAS code divisions to multipath signal, group Unit 1620 is closed each channel estimation of every multipath channel can also be combined to obtain the letter of every multipath channel Estimate in road.
Figure 17 shows the flow chart of channel estimation methods 1700 according to an aspect of the present invention.This method 1700 may include in step 1701 via wireless communication channel receiving signal, in step 1702 detection receives signal LAS code training sequences, step 1703 by receive signal in LAS codes training sequence and local LAS Code training sequence performs auto-correlation computation, and is carried out wirelessly from the result of auto-correlation computation in step 1704 The channel estimation of channel.The step of above-mentioned detecting step, auto-correlation step and progress channel estimation, can be according to upper The mode of text description is realized, therefore is repeated no more.
In the alternative embodiment of twice of channel estimation is done for two long LAS codes, each LAS can be directed to Code training sequence performs step 1703 and 1704 and estimated with obtaining the first channel estimation and second channel respectively. In this case, this method 1700 may include to combine the first channel estimation and second channel in step 1705 Estimate to obtain the channel estimation of the wireless channel.Combination can be as described above combination perform, And extend to and do not carry out channel estimation for two or more LAS code divisions.
In the alternative embodiment that signal is included via the multipath signal of multi-path channel transmission is received, this method 1700 can further comprise carrying out local LAS codes training sequence for every multipath channel in step 1706 Displacement, and it is in step 1703 and 1704 that the LAS codes training sequence in reception signal is more with being directed to every The local LAS codes training sequence of footpath channel displacement performs auto-correlation computation to carry out the letter of every multipath channel Estimate in road.In the case where not carrying out channel estimation with two or more long LAS code divisions to multipath signal, Each channel estimation of every multipath channel can be combined in step 1705 to obtain the channel of every multipath channel Estimation.
After channel estimation is carried out, receiving terminal can demodulate what is received using the channel estimation carried out Unknown data signal, to determine the actual data signal of transmitting terminal transmission.
Although illustrating channel estimation by taking LAS codes as an example above, other can be used in real process Midamble code carry out channel estimation, for example m-sequence, Golomb codes, CAN (Cyclic Algorithm New), And any other suitable midamble code, it is of the invention unrestricted in this regard.By the present invention in that training sequence Row frequency range is much larger than data bandwidth so that the power spectral density of training sequence is less than data power spectral density, when Also will not mutually it be interfered when training sequence is overlapping, training sequence does not monopolize specific frequency and time money Source, can improve the availability of frequency spectrum and transmission rate of system, and can improve the time in channel estimation process The accuracy of resolution ratio so that channel estimation results are more accurate.
It will be understood by those skilled in the art that various different technologies and skill can be used in information, signal and data In any technology and skill represent.For example, above description quote from the whole text data, instruction, order, Information, signal, position (bit), symbol and chip can be by voltage, electric current, electromagnetic wave, magnetic field or magnetic Particle, light field or optical particle or its any combinations are represented.
Those skilled in the art will further appreciate that what is described with reference to the embodiments described herein is various Illustrative logic plate, module, circuit and algorithm steps can realize for electronic hardware, computer software, Or combination of the two.Clearly to explain this interchangeability of hardware and software, various illustrative components, Frame, module, circuit and step are to make vague generalization description in its functional form above.Such work( Energy property is implemented as hardware or software depends on concrete application and puts on the design constraint of total system. Technical staff can realize described feature for every kind of application-specific with different modes, but such Realize that decision-making should not be interpreted to cause departing from the scope of the present invention.
General place can be used with reference to the various illustrative logic modules and circuit that presently disclosed embodiment is described Manage device, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA) or other PLDs, discrete door or transistor logic, discrete nextport hardware component NextPort, Or it is designed to carry out any combinations of function described herein to realize or perform.General processor can be Microprocessor, but in alternative, the processor can be any conventional processor, controller, micro- Controller or state machine.Processor is also implemented as the combination of computing device, such as DSP with it is micro- The combination of processor, multi-microprocessor, the one or more microprocessors cooperated with DSP core or Any other such configuration.
Can be embodied directly in hardware, in reference to the method that embodiment disclosed herein is described or the step of algorithm by Embodied in the software module of computing device or in combination of the two.Software module can reside in RAM Memory, flash memory, ROM memory, eprom memory, eeprom memory, register, In hard disk, removable disk, the storage medium of CD-ROM or any other form known in the art. Exemplary storage medium is coupled to processor to enable the processor to read and write from/to the storage medium Information.In alternative, storage medium can be integrated into processor.Processor and storage medium can be stayed Stay in ASIC.ASIC can reside in user terminal.In alternative, processor and storage are situated between Matter can be resident in the user terminal as discrete assembly.
In one or more exemplary embodiments, described function can hardware, software, firmware or its Realized in any combinations.If being embodied as computer program product in software, each function can be used as one Bar or more bar is instructed or code storage is transmitted on a computer-readable medium or by it.It is computer-readable Medium includes both computer-readable storage medium and communication media, and it includes facilitating computer program from a ground to another Any medium of one ground transfer.Storage medium can be any usable medium that can be accessed by a computer.As Example and it is non-limiting, such computer-readable medium may include RAM, ROM, EEPROM, CD-ROM Other optical disc storages, disk storage or other magnetic storage apparatus or can be used to carry or store instruction or The desirable program code of data structure form and any other medium that can be accessed by a computer.Any connection It is properly termed a computer-readable medium.If for example, software be using coaxial cable, fiber optic cables, The wireless skill of twisted-pair feeder, digital subscriber line (DSL) or such as infrared, radio and microwave etc Art from web site, server or other remote sources transmit, then the coaxial cable, fiber optic cables, The wireless technology of twisted-pair feeder, DSL or such as infrared, radio and microwave etc is just included in Jie Among the definition of matter.As used herein disk (disk) and dish (disc) including compact disc (CD), Laser disc, laser disc, digital versatile disc (DVD), floppy disk and blu-ray disc, which disk (disk) often with The mode reproduce data of magnetic, and dish (disc) laser reproduce data optically.Combinations of the above It should be included within the scope of computer readable media.
It is for so that any person skilled in the art all can make or make to provide of this disclosure be previously described Use the disclosure.Various modifications of this disclosure all will be apparent for a person skilled in the art, and The generic principles defined herein can be applied to spirit or model of other variants without departing from the disclosure Enclose.Thus, the disclosure is not intended to be limited to example described herein and design, but should be awarded Give the widest scope consistent with novel features with principle disclosed herein.

Claims (20)

1. a kind of channel estimation methods, including：
Receive signal, including midamble code and data, wherein midamble code frequency range are more than data bandwidth and midamble code Power spectral density be less than data power spectral density, and the midamble code and the data be frequency and/or when Between at least partially overlappingly send；
Detection receives the midamble code in signal；
The midamble code received in signal and local midamble code are performed into auto-correlation computation；And
Channel estimation is carried out from the result of the auto-correlation computation.
2. channel estimation methods as claimed in claim 1, it is characterised in that in the reception signal Midamble code includes receiving the midamble code of signal first and receives the midamble code of signal second, and the local midamble code includes Local first midamble code and local second midamble code,
Performing auto-correlation computation includes：
The midamble code of signal first and local first midamble code will be received to perform the first auto-correlation computation to carry out the One channel estimation；
The midamble code of signal second and local second midamble code will be received to perform the second auto-correlation computation to carry out the Two channel estimations；And
Combine the result of the first channel estimation and the result of second channel estimation.
3. channel estimation methods as claimed in claim 2, it is characterised in that the first channel estimation of combination Result and the result of second channel estimation include to the estimation of the result and second channel of the first channel estimation As a result it is averaged.
4. channel estimation methods as claimed in claim 2, it is characterised in that the midamble code includes m Sequence, Golomb codes, CAN codes or LAS codes.
5. channel estimation methods as claimed in claim 4, it is characterised in that the midamble code frequency range is big 5 times, 10 times, 15 times or more in data bandwidth.
6. channel estimation methods as claimed in claim 2, it is characterised in that the reception signal includes Via the multipath signal of multi-path channel transmission, methods described further comprises：
Local midamble code is shifted for every multipath channel；And
The midamble code received in signal and the local midamble code for every multipath channel displacement are performed from phase Computing is closed to carry out the channel estimation of every multipath channel.
7. channel estimation methods as claimed in claim 6, it is characterised in that also include：
Local first midamble code is shifted for every multipath channel；
The midamble code of signal first will be received to perform with local first midamble code for every multipath channel displacement Auto-correlation computation is to carry out the first channel estimation of every multipath channel；
Local second midamble code is shifted for every multipath channel；
The midamble code of signal second will be received to perform with local second midamble code for every multipath channel displacement Auto-correlation computation is estimated with the second channel for carrying out every multipath channel；And
First channel estimation and second channel of every multipath channel of combination are estimated to obtain every multipath channel Channel estimation.
8. channel estimation methods as claimed in claim 6, it is characterised in that for every multipath channel Local midamble code is carried out into displacement includes local midamble code is moved into a position for every multipath channel.
9. channel estimation methods as claimed in claim 1, it is characterised in that detection is received in signal Midamble code is will to receive signal and local code execution auto-correlation computation by using sliding window method and detect auto-correlation Peak value is carried out.
10. channel estimation methods as claimed in claim 1, it is characterised in that the midamble code includes instruction Practice sequence [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LNIn LAS long codes, wherein [0]SNFor length Spend 0 sequence for SN, [Xlas]SNThe LAS short codes for being SN for length, [Xlas]LNIt is LN for length LAS long codes, the LAS long codes be used for carry out channel estimation.
11. a kind of channel estimating apparatus, including：
Signal receiving unit, for receiving signal, the signal of reception includes midamble code and data, wherein training Code frequency range is more than power spectral density of the power spectral density less than data of data bandwidth and midamble code, and the instruction Practice code and the data are at least partially overlappingly sent in frequency and/or on the time；
Synchronization unit, it detects the midamble code received in signal；And
Autocorrelation calculation unit, the midamble code received in signal and local midamble code are performed auto-correlation and transported by it Calculate, and channel estimation is carried out from the result of the auto-correlation computation.
12. channel estimating apparatus as claimed in claim 11, it is characterised in that in the reception signal Midamble code include receive the midamble code of signal first and receive the midamble code of signal second, the local midamble code bag Include local first midamble code and local second midamble code；
The autocorrelation calculation unit is configured to that the midamble code of signal first and local first midamble code will be received The first auto-correlation computation is performed to carry out the first channel estimation and the midamble code of signal second will be received and local Second midamble code performs the second auto-correlation computation to carry out second channel estimation,
Wherein described channel estimating apparatus also include assembled unit, for combine the first channel estimation result and The result of second channel estimation.
13. channel estimating apparatus as claimed in claim 12, it is characterised in that the assembled unit group Closing the result of the first channel estimation and the result of second channel estimation includes the assembled unit to the first channel The result of result and the second channel estimation of estimation is averaged.
14. channel estimating apparatus as claimed in claim 12, it is characterised in that the midamble code includes M-sequence, Golomb codes, CAN codes or LAS codes.
15. channel estimating apparatus as claimed in claim 14, it is characterised in that the midamble code frequency range 5 times, 10 times, 15 times or more more than data bandwidth.
16. channel estimating apparatus as claimed in claim 12, it is characterised in that the reception signal bag The multipath signal via multi-path channel transmission is included, described device further comprises：
Shift unit, it is shifted local midamble code for every multipath channel,
Wherein described autocorrelation calculation unit is by the midamble code received in signal with being moved for every multipath channel The local midamble code of position performs auto-correlation computation to carry out the channel estimation of every multipath channel.
17. channel estimating apparatus as claimed in claim 16, it is characterised in that：
The shift unit is configured to be shifted local first midamble code for every multipath channel, pin Every multipath channel is shifted local second midamble code；
The autocorrelation calculation unit is configured to receive the midamble code of signal first with believing for every multipath Local first midamble code of road displacement is performed auto-correlation computation and estimated with the first channel for carrying out every multipath channel Count and the midamble code of signal second will be received and performed with local second midamble code for every multipath channel displacement Auto-correlation computation is estimated with the second channel for carrying out every multipath channel；And
The assembled unit combines the first channel estimation and the second channel estimation of every multipath channel.
18. channel estimating apparatus as claimed in claim 16, it is characterised in that the shift unit pin Local midamble code is carried out into displacement to every multipath channel includes the shift unit for every multipath channel Local midamble code is moved into a position.
19. channel estimating apparatus as claimed in claim 11, it is characterised in that the synchronization unit inspection The midamble code surveyed in reception signal is that reception signal and local code are performed into auto-correlation by using sliding window method to transport Calculate and detect autocorrelation peak to carry out.
20. channel estimating apparatus as claimed in claim 11, it is characterised in that the midamble code includes Training sequence [0]SN,[Xlas]SN,[0]SN,[Xlas]SN,[Xlas]LN,[Xlas]LNIn LAS long codes, wherein [0]SNFor length Spend 0 sequence for SN, [Xlas]SNThe LAS short codes for being SN for length, [Xlas]LNIt is LN for length LAS long codes, the LAS long codes be used for carry out channel estimation.
CN201610216412.8A 2016-04-08 2016-04-08 Channel estimation method and device Active CN107294882B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201610216412.8A CN107294882B (en) 2016-04-08 2016-04-08 Channel estimation method and device
PCT/CN2017/079579 WO2017174002A1 (en) 2016-04-08 2017-04-06 Channel estimation method and device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610216412.8A CN107294882B (en) 2016-04-08 2016-04-08 Channel estimation method and device

Publications (2)

Publication Number Publication Date
CN107294882A true CN107294882A (en) 2017-10-24
CN107294882B CN107294882B (en) 2021-10-26

Family

ID=60093497

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610216412.8A Active CN107294882B (en) 2016-04-08 2016-04-08 Channel estimation method and device

Country Status (1)

Country Link
CN (1) CN107294882B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108173788A (en) * 2018-01-03 2018-06-15 深圳市极致汇仪科技有限公司 A kind of channel estimation methods and its system based on OFDM wireless systems

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1452326A (en) * 2002-04-15 2003-10-29 华为技术有限公司 Method for switching-on and synchronization of mobile terminal of radio local network system
CN1663161A (en) * 2002-06-25 2005-08-31 皇家飞利浦电子股份有限公司 MT-CDMA using spreading codes with interference-free windows
CN1992574A (en) * 2005-12-31 2007-07-04 方正通信技术有限公司 Method and apparatus for improving networking performance of CDMA communication system
CN101018225A (en) * 2006-12-19 2007-08-15 北京创毅视讯科技有限公司 OFDM symbol and frequency synchronization and channel style estimating method
CN101039294A (en) * 2006-03-15 2007-09-19 方正通信技术有限公司 Method for improving channel estimation characteristic and synchronization characteristic of generalized multi-carrier system
CN101170346A (en) * 2006-10-26 2008-04-30 富士通株式会社 Pilot signal transmission method and mobile communication system
US20110182169A1 (en) * 2009-09-13 2011-07-28 Research Institute Of Tsinghua University In Shenzhen Code division multiplexing method and system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1452326A (en) * 2002-04-15 2003-10-29 华为技术有限公司 Method for switching-on and synchronization of mobile terminal of radio local network system
CN1663161A (en) * 2002-06-25 2005-08-31 皇家飞利浦电子股份有限公司 MT-CDMA using spreading codes with interference-free windows
CN1992574A (en) * 2005-12-31 2007-07-04 方正通信技术有限公司 Method and apparatus for improving networking performance of CDMA communication system
CN101039294A (en) * 2006-03-15 2007-09-19 方正通信技术有限公司 Method for improving channel estimation characteristic and synchronization characteristic of generalized multi-carrier system
CN101170346A (en) * 2006-10-26 2008-04-30 富士通株式会社 Pilot signal transmission method and mobile communication system
CN101018225A (en) * 2006-12-19 2007-08-15 北京创毅视讯科技有限公司 OFDM symbol and frequency synchronization and channel style estimating method
US20110182169A1 (en) * 2009-09-13 2011-07-28 Research Institute Of Tsinghua University In Shenzhen Code division multiplexing method and system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108173788A (en) * 2018-01-03 2018-06-15 深圳市极致汇仪科技有限公司 A kind of channel estimation methods and its system based on OFDM wireless systems
CN108173788B (en) * 2018-01-03 2020-11-20 深圳市极致汇仪科技有限公司 Channel estimation method and system based on OFDM wireless system

Also Published As

Publication number Publication date
CN107294882B (en) 2021-10-26

Similar Documents

Publication Publication Date Title
CN107276953A (en) Time synchronization method, device and system
CN107276926A (en) Channel estimation methods and device
CN107276654B (en) Signal processing method and system
CN107294882A (en) Channel estimation methods and device
CN107276927A (en) Channel estimation methods and device
CN107294881A (en) Channel estimation methods and device
CN107276955A (en) Signal processing method and system
CN107276740A (en) Time synchronization method, device and system
CN107276708A (en) Time synchronization method, device and system
CN107276943A (en) Time synchronization method, device and system
CN107294883A (en) Channel estimation methods and device
CN107276929A (en) Channel estimation methods and device
CN107276930A (en) Channel estimation methods and device
CN107277913A (en) Time synchronization method, device and system
CN107276940A (en) Time synchronization method, device and system
CN107294889B (en) Carrier synchronization method and device
CN107276925B (en) Channel estimation method and device
CN107276946A (en) Carrier synchronization method and device
CN107276949A (en) Signal processing method and system
CN107276951A (en) Carrier synchronization method and device
CN107276947A (en) Signal processing method and system
CN107276952A (en) Carrier synchronization method and device
CN107276655A (en) Signal processing method and system
CN107276956A (en) Carrier synchronization method and device
CN107276948A (en) Carrier synchronization method and device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
TA01 Transfer of patent application right

Effective date of registration: 20190808

Address after: 518057 2nd Floor, No. 9 Software Building, Zhongxin Road, Yuehai Street, Nanshan District, Shenzhen City, Guangdong Province

Applicant after: Shenzhen Guangqi Hezhong Technology Co., Ltd.

Address before: Bantian street Longgang District of Shenzhen City, Guangdong province 518000 Jihua Road, the new world Huasai Industrial Area No. 2, building 101 (two floor) 201

Applicant before: SHENZHEN CHAOJI DATA CHAIN TECHNOLOGY CO., LTD.

TA01 Transfer of patent application right
GR01 Patent grant
GR01 Patent grant
TA01 Transfer of patent application right

Effective date of registration: 20211012

Address after: 221400 No.09, south side of 311 National Road, Shuangtang industrial cluster, Xinyi City, Xuzhou City, Jiangsu Province

Applicant after: Xinyi avatar Intelligent Technology Co., Ltd

Address before: 518057 2nd floor, software building, No.9, Gaoxin middle 1st Road, Yuehai street, Nanshan District, Shenzhen City, Guangdong Province

Applicant before: SHEN ZHEN KUANG-CHI HEZHONG TECHNOLOGY Ltd.

TA01 Transfer of patent application right