CN106603459A - Generating method and receiving method for preamble symbol - Google Patents
Generating method and receiving method for preamble symbol Download PDFInfo
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- CN106603459A CN106603459A CN201611189364.4A CN201611189364A CN106603459A CN 106603459 A CN106603459 A CN 106603459A CN 201611189364 A CN201611189364 A CN 201611189364A CN 106603459 A CN106603459 A CN 106603459A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2692—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/2605—Symbol extensions, e.g. Zero Tail, Unique Word [UW]
- H04L27/2607—Cyclic extensions
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
- H04L27/2613—Structure of the reference signals
Abstract
The invention provides a generating method and a receiving method for a preamble symbol. The generating method is characterized by comprising the steps of: generating a time domain symbol having an arbitrarily three-segment structure based on an obtained time-domain main body signal; and generating a preamble symbol based on one or two time domain symbols. The generating method and the receiving method solve the problems that a DVB_T2 time domain structure in the existing DVB_T2 standard and other standards cannot be applied to coherent detection and the failure probability of the preamble symbol occurs in low-complexity receiving algorithm detection under a complex frequency selective fading channel.
Description
The application is the divisional application of original bill, the application number 201410753506.X of original bill, December 10 2014 applying date
Day, invention and created name《The generation method and method of reseptance of leading symbol》.
Technical field
The present invention relates to wireless broadcast communication technical field, the generation method of more particularly to a kind of leading symbol and recipient
Method.
Background technology
The data that transmitting terminal is sent correctly are demodulated generally for the receiving terminal for enabling ofdm system, ofdm system is necessary
Realize between transmitting terminal and receiving terminal accurately and reliably time synchronized.Simultaneously as ofdm system is very quick to the frequency deviation of carrier wave
Sense, the receiving terminal of ofdm system it is also required to provide the carrier spectrum method of estimation of precise and high efficiency, to carry out accurately to carrier wave frequency deviation
Estimation and correction.
At present, realize the synchronous method of transmitting terminal and destination time substantially based on leading symbol come real in ofdm system
Existing.Leading symbol is all known symbol sebolic addressing of transmitting terminal and receiving terminal of ofdm system, leading symbol mark physical frame
Beginning (being named as P1 symbols), only there is a P1 symbol in each physics frame in or multiple P1 symbols continuously occur, P1 symbol
Number purposes include：
1) whether transmission is the signal for expecting to receive in receiving terminal is rapidly detected to determine channel；
2) basic configured transmission (such as FFT points, frame type information etc.) is provided, receiving terminal is carried out at receipt of subsequent
Reason；
3) original carrier frequency deviation and timing error are detected, to compensate after reach frequency and Timing Synchronization；
4) emergency alarm or broadcast system wake up.
Propose in DVB_T2 standards based on the P1 Design of Symbols of CAB spatial structures, preferably realize above-mentioned functions.But
It is still have some to limit on low complex degree receiving algorithm.For example, in the long multipath letter of 1024,542 or 482 symbols
During road, being timed using the such three-stage structures of CAB slightly synchronously can occur relatively large deviation, cause to estimate carrier wave integral multiple on frequency domain
There is mistake in frequency deviation.In addition, in complex frequency Selective Fading Channel, such as during long multipath, DBPSK differential decodings are likely to
Can fail.It is additionally, since in DVB_T2 spatial structures without Cyclic Prefix, and if needing to carry out the frequency-domain structure group of channel estimation
Close, the problem of its channel estimation in frequency domain performance degradation will be caused.
The content of the invention
The problem that the present invention is solved is that in current DVB_T2 standards and other standards, there be not the present invention in DVB_T2 spatial structures
The problem of solution is in current DVB_T2 standards and other standards, without Cyclic Prefix in DVB_T2 spatial structures, it is impossible to be suitable for
In relevant detection, and there is failure in leading symbol low complex degree receiving algorithm detection under complex frequency Selective Fading Channel
The problem of probability.
To solve the above problems, a kind of generation method of leading symbol is embodiments provided, it is characterised in that bag
Include following steps：The time domain with any one three-stage structure in following two kinds is generated based on resulting time domain main running signal
Symbol；And leading symbol is generated based on one or two time-domain symbols, wherein, the first three-stage structure is：Time domain main body
Signal, the prefix generated based on the rear portion of the time domain main running signal and modulated based on the rear portion of the time domain main running signal
The suffix of generation, second three-stage structure be：Time domain main running signal, generated based on the rear portion of the time domain main running signal before
Sew and sewing in advance for generation is modulated based on the rear portion of the time domain main running signal, generate when based on a time-domain symbol general
Logical leading symbol, the splicing when being had the time-domain symbol of different three-stage structures based on two is generated and strengthens leading symbol.
Alternatively, time domain main running signal is that the frequency-domain OFDM symbol to predetermined length carries out inverse discrete fourier transform and obtains
The time-domain OFDM symbol for arriving.
Alternatively, frequency-domain OFDM symbol includes virtual subcarrier, signaling sequence subcarrier and fixed sequence program subcarrier, right
After signaling sequence subcarrier and fixed sequence program subcarrier are arranged according to the predetermined rule that is staggered, by virtual subnet distribution of carriers
In its both sides, the predetermined rule that is staggered is comprising any one in following two rules：The first predetermined rule that is staggered：It is in
Oem character set is occasionally very staggeredly arranged；And the second predetermined rule that is staggered：A part of signaling sequence is placed on very
Number subcarrier, another part signaling sequence is placed on even subcarriers, and a part of fixed sequence program is placed on odd subcarriers, another
Part fixed sequence program is placed on even subcarriers.
Alternatively, in prefix, suffix or the generation step sewed in advance, comprise the steps of：By time domain main running signal
Used as Part I, the least significant end of neat Part I takes out a part according to the predetermined rule that obtains, and advises according to the first predetermined process
Then processed and copied to the front portion of the Part I to generate Part III so as to as prefix, meanwhile, from Part I
Rear portion according to it is predetermined obtain rule take out a part, this first is processed and copied to according to the second predetermined process rule
Point rear portion or process and copy to the front portion of prefix generating Part II so as to mutually should be used as suffix respectively or sewing in advance.
Alternatively, wherein, the predetermined rule that obtains includes：If LenBFor the length of Part II, LenCFor the length of Part III
Degree, LenB≤LenC, the sampled point sequence number of the corresponding Part I of starting point for separately setting N1 to select to be copied to Part II, N2 is
Selection is copied to the sampled point sequence number of the corresponding Part I of terminal of Part II, then meet below equation：N2=N1+
LenB-1。
Alternatively, wherein, the first predetermined process rule includes：Direct copying；Or each in taken out part is adopted
Sample signal is multiplied by an identical fixed coefficient or predetermined difference coefficient, and the second predetermined process rule includes：When the first predetermined process
Rule is modulated process when being direct copying；Or when the first predetermined process rule for institute taking-up part in each sample believe
Also being multiplied by after corresponding coefficient when number being multiplied by an identical fixed coefficient or predetermined difference coefficient carries out modulation treatment.
Alternatively, wherein, common leading symbol is based on same time domain main running signal, by the first three-stage structure and the
Any one in two kinds of three-stage structures is for identifying emergent broadcast.
Alternatively, wherein, in strengthening two different time domain symbols of leading symbol, two time domain main running signal is different,
And the three-stage structure of employing is also different, the different successively sequences by two time-domain symbols are leading to form the first reinforcement respectively
Symbol and second reinforcement leading symbol, for identifying emergent broadcast.
The embodiment of the present invention additionally provides a kind of method of reseptance of leading symbol, it is characterised in that comprise the steps：Step
Rapid S2-1：Physical frame to receiving is processed to obtain baseband signal；Step S2-2：Judge to whether there is in baseband signal
Expect the common leading symbol in the claim 1 for receiving or strengthen leading symbol；Step S2-3：When being judged as YES, it is determined that should
Position of the leading symbol in physical frame simultaneously solves the signaling information entrained by the leading symbol.
Alternatively, physical frame is processed and is comprised the steps with obtaining baseband signal：When the signal for receiving is zero
During intermediate-freuqncy signal, after analog-to-digital conversion, then filter, down-sampling process obtain baseband signal, when the signal for receiving be intermediate-freuqncy signal
When, frequency spectrum shift after analog-to-digital conversion, then filter, down-sampling process obtain baseband signal.
Alternatively, in the case of the common leading symbol of the only possible transmission of known transmitting terminal, judge whether deposited in baseband signal
Comprise the steps in the common leading symbol for expecting to receive：Step S2-21A：Receive according to the expectation in such as claim 7
Part III, the predetermined acquisition between any two of Part I and Part II in common leading symbol is regular and/or predetermined
Rule is processed, baseband signal is carried out to carry out postponing slip auto-correlation after correspondingly inverse processing and signal demodulation, to obtain three
It is individual to postpone related accumulated value；Step S2-21B：Performed mathematical calculations based at least one of related accumulated value of these three delays,
And peakvalue's checking is carried out to the mathematical operation result；And step S2-21C：If the result of peakvalue's checking meets pre-conditioned,
Determine there is the common targeting signal for expecting to receive in baseband signal.
Alternatively, known transmitting terminal it is only possible send strengthen leading symbol in the case of, whether judge in baseband signal
There is the reinforcement leading symbol for expecting to receive to comprise the steps：Step S2-22A：According to the reinforcement leading symbol for expecting to receive
In the Part III of the first three-stage structure and second three-stage structure, Part I and Part II between any two predetermined
Rule and/or predetermined process rule are obtained, baseband signal is carried out to carry out delay cunning after correspondingly inverse processing and signal demodulation
Dynamic auto-correlation, to obtain six related accumulated value is postponed, and this six values are actual by 3 delay correlators acquisitions, wherein, work as reinforcement
When the fixed sequence program of two symbols of leading symbol adopts identical, the Part III and first of former and later two symbols is also obtained
The delay correlation accumulated value of partial combined and spliced part；Step S2-22B：Six of step S2-22A are postponed related cumulative
Value have same delay relation carrying out be added or phase adjustment after be added, obtain the related accumulated value of three different delays, base
In prolonging for the combined and spliced part of the Part III and Part I of these three related accumulated values of delay and former and later two symbols
Late at least one of correlation accumulated value performs mathematical calculations, and carries out peakvalue's checking to the mathematical operation result；Step S2-
22C：If the result of peakvalue's checking meets pre-conditioned, it is determined that there is the reinforcement targeting signal for expecting to receive in baseband signal.
Optionally it is determined that position of the leading symbol in physical frame includes：Based on meeting pre-conditioned peakvalue's checking
Result determining position of the leading symbol in physical frame, it is big according to peak value if there is the leading symbol for expecting to receive
Either maximum determines position or carry out fractional part of frequency offset estimation that leading symbol occurs in physical frame to residing partial value.
Alternatively, using leading symbol all or part of time domain waveform and/or the leading symbol all or part when
The frequency-region signal that domain waveform is obtained after Fourier transformation, to solve the signaling information entrained by the leading symbol including as follows
Step:By the signal comprising signaling sequence subcarrier and signaling sequence t easet ofasubcarriers or the signaling sequence t easet ofasubcarriers pair
The time-domain signal answered carries out computing, to solve the leading symbol in signaling information by entrained by signaling sequence subcarrier, wherein
Signaling sequence t easet ofasubcarriers are produced based on known signaling sequence set.
Alternatively, the method for reseptance of the leading symbol in the embodiment of the present invention, it is characterised in that also comprise the steps：1)
According to position of the leading symbol in physical frame is determined, the signal comprising fixed subcarrier is intercepted；2) by this comprising fixation
The signal of subcarrier time-domain signal corresponding with frequency domain stator carrier wave sequence or the frequency domain stator carrier wave sequence carries out computing,
To obtain integer frequency offset estimation or channel estimation.
Compared with prior art, technical solution of the present invention has the advantages that：
The generation method of the leading symbol for providing according to embodiments of the present invention with method of reseptance, from after time domain main running signal
When portion intercepts the signal of certain length as Cyclic Prefix or sews in advance, relevant detection is capable of achieving, solves noncoherent detection
The problem of hydraulic performance decline, and the signal generation modulated signal of the circulating prefix-length based on above-mentioned intercepting so that generated
There is leading symbol good fractional part of frequency offset to estimate performance and Timing Synchronization performance, further, can according to efficiency of transmission and
The requirement of robustness selects transmission one, and either two symbols, respectively as common leading symbol or reinforcement leading symbol, work as biography
When sending the symbol of a three-stage structure as leading symbol, based on same OFDM symbol main body, different by two kinds of design
Three-stage structure, carrys out identifying emergent broadcast；When the symbol of two three-stage structures is transmitted as leading symbol, two OFDM symbol
Main body is different, and the three-stage structure for adopting is also just different, on this basis, by the sequencing arrangement of two three-stage structures
Carry out identifying emergent broadcast, by the different three-stage structure of two symbols, the appearance under some particular length multipath channels can be avoided
It is little inclined estimation failure problem, further, the present invention leading symbol using three sections have part identical content knots
Structure, it is ensured that in the peak value that receiving terminal may be significantly using delay correlation, also, during the leading symbol is generated,
The modulated signal of design time domain main body number can avoid receiving terminal from being subject to continuous wave CO_2 laser or mono-tone interference, or occur and adjust
Occur missing when protection interval length is identical with modulated signal length in the isometric multipath channel of signal length processed, or reception signal
Situation as detection peak value.
Description of the drawings
Fig. 1 is the schematic flow sheet of the embodiment of the generation method of the leading symbol of the present invention；
Fig. 2 is the schematic diagram of three-stage structure in the first common leading symbol in embodiments of the invention；
Fig. 3 is the schematic diagram of three-stage structure in second common leading symbol in embodiments of the invention；
Fig. 4 is to obtain the schematic diagram of process based on the first common leading symbol in embodiments of the invention；
Fig. 5 is the schematic diagram processed based on second common leading symbol acquisition in embodiments of the invention；
Fig. 6 is the schematic diagram that the first strengthens two three-stage structures in leading symbol in embodiments of the invention；
Fig. 7 is the schematic diagram that second is strengthened two three-stage structures in leading symbol in embodiments of the invention；
Fig. 8 is to obtain the schematic diagram of process based on the first reinforcement leading symbol in embodiments of the invention；
Fig. 9 is to strengthen the schematic diagram that leading symbol obtains process based on second in embodiments of the invention；
Figure 10 is signaling sequence subcarrier in embodiments of the invention, fixed sequence program subcarrier and virtual subcarrier according to
The arrangement schematic diagram of the one predetermined rule that is staggered；
Figure 11 is signaling sequence subcarrier in embodiments of the invention, fixed sequence program subcarrier and virtual subcarrier according to
The arrangement schematic diagram of the two predetermined rules that are staggered；
Figure 12 is that the two time domain main running signals strengthened in embodiments of the invention in leading symbol are regular with predetermined association
In shift value 1 carry out the arrangement schematic diagram of relative integral shift；
Figure 13 is that the two time domain main running signals strengthened in embodiments of the invention in leading symbol are regular with predetermined association
In shift value 2 carry out the arrangement schematic diagram of relative integral shift；
Figure 14 is the schematic flow sheet of the specific embodiment of the method for reseptance of the leading symbol of the present invention；
Figure 15 is that the peak value of the first the common leading symbol in embodiments of the invention corresponding to three-stage structure CAB is obtained
The logical schematic for taking；
Figure 16 is that the peak value of second common leading symbol in embodiments of the invention corresponding to three-stage structure BCA is obtained
The logical schematic for taking；
Figure 17 is the logical schematic that the first peak value for strengthening leading symbol is obtained in embodiments of the invention；And
Figure 18 is the logical schematic that the peak value of second reinforcement leading symbol in embodiments of the invention is obtained.
Specific embodiment
In the current DVB_T2 standards of inventor's discovery and other standards, without Cyclic Prefix in DVB_T2 spatial structures, no
Relevant detection is can be suitably used for, and leading symbol low complex degree receiving algorithm under complex frequency Selective Fading Channel is detected
The problem of existing probability of failure.
For the problems referred to above, inventor is through research, there is provided a kind of generation method and method of reseptance of leading symbol, solution
The problem of noncoherent detection of having determined hydraulic performance decline, with good fractional part of frequency offset performance and Timing Synchronization performance are estimated, may be used also
The problem for avoiding the little inclined estimation occurred under some particular length multipath channels from failing, it is ensured that related using postponing in receiving terminal
The peak value that may be significantly, it is to avoid the situation of the above-mentioned error detection peak value of appearance.
In order that the above objects, features and advantages of the present invention can become apparent from it is understandable, below in conjunction with the accompanying drawings to this
Bright specific embodiment is described in detail.
Fig. 1 is the schematic flow sheet of the embodiment of the generation method of the leading symbol of the present invention.As shown in figure 1, this enforcement
The generation method of leading symbol comprises the steps in example：
Step S1-1：Obtain time domain main running signal；
Step S1-2：Generated based on resulting time domain main running signal with the first three-stage structure and second three sections of knots
The time-domain symbol of any one three-stage structure in structure；And
Step S1-3：Leading symbol is generated based on one or two time-domain symbols,
Wherein, the first three-stage structure is：Time domain main running signal, generated based on the rear portion of the time domain main running signal before
Sew and the suffix of generation is modulated based on the rear portion of the time domain main running signal, second three-stage structure is：Time domain main body is believed
Number, the prefix that generated based on the rear portion of the time domain main running signal and life is modulated based on the rear portion of the time domain main running signal
Into sew in advance.
When generating leading symbol when based on a time-domain symbol, the leading symbol is common leading symbol；When based on two
When splicing generates leading symbol during the time-domain symbol of individual different three-stage structures, the leading symbol is reinforcement leading symbol.
Fig. 2 is the schematic diagram of three-stage structure in the first common leading symbol in embodiments of the invention.Fig. 3 is the present invention
Embodiment in second common leading symbol three-stage structure schematic diagram.
By one section of time domain main running signal (being indicated using A in figure), used as Part I, the least significant end of neat Part I is according to pre-
The fixed rule that obtains takes out a part, and the anterior next life of the Part I is processed and copied to according to the first predetermined process rule
Into Part III (in figure using C indicate) so as to as prefix, meanwhile, take out according to the predetermined rule that obtains from the rear portion of Part I
A part, before being processed and copied to the rear portion of the Part I or process and copy to according to the second predetermined process rule
The front portion sewed generating Part II (in figure with B sign) so as to mutually should be used as suffix respectively or sewing in advance, so as to generate respectively
B as shown in Figure 2 as suffix the first common leading symbol (CAB structures) and B as shown in Figure 3 sewed in advance
Two kinds of common leading symbols (BCA structures).
In the present embodiment, when the first common leading symbol is sent, represent that system is sending general broadcast service；When send out
When sending second common leading symbol, represent that system is sending emergent broadcast service.The present invention can also send the first general
During logical leading symbol, system is represented in transmission emergent broadcast service, and when sending second common leading symbol, the system of expression exists
Send general broadcast service.Common leading symbol is based on same time domain main running signal, and by the first three-stage structure, (CAB is tied
Structure) and second three-stage structure (BCA structures) in any one for identifying emergent broadcast.
Carry out after with regard to obtaining out Part III, Part II from Part I for process specific rules, first is pre-
The fixed rule that processes includes：Direct copying；Or an identical fixed coefficient is multiplied by each sampled signal in taken out part
Or predetermined difference coefficient.Second predetermined process rule includes：Place is modulated when the first predetermined process rule is direct copying
Reason；Or when the first predetermined process rule for each sampled signal in taking-up part be multiplied by an identical fixed coefficient or in advance
Corresponding coefficient is also multiplied by during fixed difference coefficient.It is, when Part III be direct copying as prefix when, Part II enters
Suffix is re-used as after row modulation treatment or is sewed in advance, and when Part III is to be multiplied by corresponding coefficient, Part II is also needed
Carry out being multiplied by coefficient and carry out modulation treatment, be re-used as suffix or sew in advance.
Fig. 4 is to obtain the schematic diagram of process based on the first common leading symbol in embodiments of the invention.
C sections are the direct copying of A sections in the present embodiment, and B sections are the modulated signal section of A sections, as shown in figure 4, such as A
Length is 1024, and the length for intercepting C is 520, and the length of B is 504, wherein when certain process is carried out to C and B, can be with
A fixed coefficient is multiplied by each sampling to signal, or a different coefficient is multiplied by each sampling.
Data area of the data area of B less than C, that is, select to surpass to the scope of part A of modulated signal section B
Go out the scope for intercepting part A as prefix C.Preferably, the length sum of the length of B and C is the length of A.
If NAFor the length of A, if LenCFor the length of C, LenBFor the length of modulated signal section B.If the sampled point sequence number of A
For 0,1 ... NA- 1. set N1 as select be copied to modulated signal section Part II B the corresponding Part I A of starting point sampled point
Sequence number, N2 is the sampled point sequence number of the corresponding Part I A of terminal for selecting to be copied to modulated signal section Part II B.Wherein,
N2=N1+LenB-1
Generally, that what is Part II B sections implemented is modulated to frequency modulation, M sequence or other sequences etc. is modulated, in this enforcement
By taking frequency modulation as an example, if P1_A (t) is the time-domain expression of A, then the time-domain expression of the first common leading symbol is
Wherein, frequency modulation value fSHThe corresponding subcarrier in frequency domain of time-domain OFDM symbol can be chosen for and be spaced i.e. 1/NAT, wherein
T is the sampling period, NAFor the length of time-domain OFDM symbol, in this example, NAFor 1024, f is takenSH=1/1024T.And frequency modulation
First phase can be arbitrarily selected, in order that correlation peak is sharp, fSHCan also select as 1/ (LenBT)。
As shown in figure 4, NA=1024；LenC=520, LenB=504, N1=520.Now CA sections include identical content
Autocorrelation lags are NA, autocorrelation lags of the CB sections comprising identical content are NA+LenB, and AB sections comprising identical content from phase
Close and postpone to be LenB。
Fig. 5 is the schematic diagram processed based on second common leading symbol acquisition in embodiments of the invention.
In the same manner, the time-domain expression of second common leading symbol is, it is noted that in order that receiving terminal processing method to the greatest extent may be used
Can be consistent, therefore in the structure of B-C-A, frequency modulation value is just with C-A-B structures conversely, and modulation can arbitrarily select first
Phase.
As shown in figure 5, NA=1024；LenC=520, LenB=504, N1=504, now CA sections are comprising identical content
Autocorrelation lags are NA, autocorrelation lags of the BC sections comprising identical content are LenB, and auto-correlation of the BA sections comprising identical content is prolonged
It is late NA+LenB。
Fig. 6 is the schematic diagram that the first strengthens two three-stage structures in leading symbol in embodiment.Fig. 7 is in embodiment
Two kinds of schematic diagrames for strengthening two three-stage structures in leading symbol.
Respectively as shown in Figure 6 and Figure 7, in strengthening two different time domain symbols of leading symbol, two time domain main body letter
Number difference, and the three-stage structure for adopting is also different, is formed respectively as in Fig. 6 by the different successively sequences of two time-domain symbols
The first strengthen leading symbol and such as second reinforcement leading symbol in Fig. 7, for identifying emergent broadcast.
On the basis of existing two kinds of common leading symbols, 2 symbols can be connected, be constituted two kinds of reinforcements leading
Symbol.When the 1st kind of reinforcement leading symbol is sent, represent that system is sending general broadcast service；Before sending second and strengthening
When leading symbol, represent that system is sending emergent broadcast service.When can also send the first reinforcement leading symbol, the system of expression exists
Emergent broadcast service is sent, and when sending second reinforcement leading symbol, represents that system is sending general broadcast service.
Strengthen leading symbol to be made up of two general symbols, the main part (i.e. A) of the two general symbols can not
Together, the capacity that so reinforcement leading symbol can transmit signaling is the twice or close twice of general leading symbol.
The detection of common leading symbol obtains peak value using the delay auto-correlation of CB sections, CA sections and BA sections, adds using
During strong leading symbol, in order that the autocorrelation value of 2 symbols can be added, more robust performance is obtained, then 2 symbols are each
Parameter N1 (i.e. N1 is the sampled point sequence number for selecting the corresponding A of starting point for being copied to modulated signal section B) need to meet certain pass
System, if the N1 of first symbol is N1_1, the N1 of second symbol is N1_2, needs to meet N1_1+N1_2=NA.And it is if right
The modulation that B sections are adopted is that if frequency modulation, frequency deviation value wants contrast.
The symbol of C-A-B structures is represented with sequence number 1, with sequence number 2 symbol of B-C-A structures is represented.It is A1 then to set P1_A (t)
Time-domain expression, P2_A (t) is the time-domain expression of A2, then the time-domain expression of the first three-stage structure is
The time-domain expression of second three-stage structure is
So, the first strengthen leading symbol time-domain expression be, here, because the length of B and the length sum of C are
The length of A, so, 2NAThe as length sum of B, C, A.
So, the time-domain expression of second reinforcement leading symbol is
Fig. 8 is to obtain the schematic diagram of process based on the first reinforcement leading symbol in embodiments of the invention.
As shown in figure 8, a preferred embodiment is, the C sections of 2 general symbols, A sections are identical with B segment length, NA=
1024；Ncp=520, LenB=504, only N1 has any different, N1_1=520, N1_2=504.It is as shown below, respectively the first
Strengthen leading symbol and second reinforcement leading symbol.
Take fSH=1/1024T, then the time-domain expression of the first three-stage structure be
Fig. 9 is to strengthen the schematic diagram that leading symbol obtains process based on second in embodiments of the invention.
As shown in figure 9, the time-domain expression of second three-stage structure is
For the source of the time domain main running signal in above-mentioned steps S1-1, it is generally the case that for general leading symbol
Speech, time domain main running signal A is to be formed time-domain OFDM symbol Jing after inverse fourier transform by frequency-domain OFDM symbol and obtained.
If P1_X is corresponding frequency-domain OFDM symbol, P1_XiMake to obtain time-domain OFDM symbol after inverse discrete fourier transform：
Wherein, M is effective non-zero
The power of carrier wave and.
P1_X frequency-domain structures be frequency-domain OFDM symbol respectively include virtual subcarrier, signaling sequence (referred to as SC) subcarrier and
Fixed sequence program (referred to as FC) subcarrier three part.
The signaling sequence subcarrier and the fixed sequence program subcarrier are arranged according to the predetermined rule that is staggered
Afterwards, by the virtual subnet distribution of carriers in its both sides, the predetermined rule that is staggered includes any in following two rules
It is a kind of：
The first predetermined rule that is staggered：Very staggeredly arranged in oem character set or idol；And
The second predetermined rule that is staggered：A part of signaling sequence is placed on odd subcarriers, another part signaling sequence
Even subcarriers are placed on, and a part of fixed sequence program is placed on odd subcarriers, another part fixed sequence program is placed on even number and carries
Ripple.
The first predetermined rule that is staggered is SC and FC oem character sets or even strange staggered discharge, and such FC is advised as pilot tone
Then discharge, realize that the more convenient second predetermined rule that is staggered of channel estimation then needs part SC sequences to be placed on odd number load
Ripple, remaining SC sequences are placed on even subcarriers；Need part FC sequences to be placed on odd subcarriers simultaneously, residual F C sequence is placed on
Even subcarriers, thus are avoided that FC or SC are all placed on even or odd subcarrier, can all decline under some special multipaths
Fall to, and such discharge can improve the complexity ignored to channel estimation, therefore be more excellent selection.
If the length of fixed sequence program is L (number for carrying effective subcarrier of fixed sequence program is L), the length of signaling sequence
Spend for P (i.e. the number of effective subcarrier of carrier signaling sequence is P), in the present embodiment, L=P.It should be noted that working as
(such as P when the length of fixed sequence program and signaling sequence is inconsistent>L), can be realized by way of zero padding sequence subcarrier
Fixed sequence program and signaling sequence are staggered by above-mentioned rule.
Figure 10 is signaling sequence subcarrier in embodiments of the invention, fixed sequence program subcarrier and virtual subcarrier according to
The arrangement schematic diagram of the one predetermined rule that is staggered.
As shown in Figure 10, this preferred embodiment in, this step includes：Fill respectively necessarily in effective subcarrier both sides
Null sequence subcarrier forming the frequency-domain OFDM symbol of predetermined length.
Along to the example that predetermined length is 1024, the G=1024-L-P of the length of null sequence subcarrier, both sides filling
(1024-L-P)/2 null sequence subcarrier.For example, 159 null sequences are respectively filled and is carried in L=P=353, then G=318, both sides
Ripple.
The frequency-domain OFDM symbol generated by the described first predetermined rule that is staggered is comprised the steps of：
(11st) fixed sequence program generation step：Fixed sequence program is made up of 353 plural numbers, and its mould is constant, the fixed sequence program
N-th value of subcarrier is expressed as：
Wherein,RFor the power ratio of FC and SC, SCiIt is 1 that mould is constant
The fixed sequence program subcarrier radian value ωnBy the predetermined fixed subcarrier radian value of first in following tables 1
Table determines；
Table 1 fixes subcarrier radian value table (by the first predetermined rule optimization that is staggered)
(12nd) signaling sequence generation step：Symbiosis is into 512 signaling sequences, i.e. Seq0, Seq1... Seq511, each letter
Make sequence Seq0～Seq511Take opposite number, i.e.-Seq respectively again0～-Seq511, receiving terminal is to distinguish using the positive and negative of correlation
Positive sequence or antitone sequence, i.e., transmit altogether 10bit signaling informations, and 512 signaling sequences can be further divided into 4 groups again, per group
128 signaling sequences, per group of 128 signaling sequences generation sub-step is as follows：
1st sub-step：Generate consensus sequence zciN (), it is Zadoff-Chu sequence zc (n) that length is N：
2nd sub-step:By copying zc twiceiN () produces length for 2N's
3rd sub-step:FromIn certain specific original position kiIntercepted length is 353 sequence, produces SCi(n)：
SCi(n)=zci *(ki- 1+n), n=0～352
Every group of signaling sequence Seq0～Seq127N values, uiWith shift value kiRespectively by each corresponding table 2 below to table 5
Predetermined signaling sequential parameter table determines.
First group of sequence Seq0～Seq127N values, uiWith shift value kiIt is as shown in table 2 below.
Table 2：First group of signaling sequence parameter
Second group of sequence Seq128～Seq255Generation step it is identical with first group of sequence, its N value, uiWith shift value kiSuch as
Shown in table 3 below.
Table 3：Second group of signaling sequence parameter
3rd group of sequence Seq256～Seq383Generation step it is identical with first group of sequence, its N value, uiWith shift value kiSuch as
Shown in table 4 below table.
Table 4：3rd group of signaling sequence parameter
4th group of sequence Seq384～Seq511Generation step it is identical with first group of sequence, itsNValue, uiWith shift value kiUnder
Shown in table 5.
Table 5：4th group of signaling sequence parameter
(13rd) arrangement filling step, will be by the fixed sequence program obtained by (11) step and (12) step and letter
Make sequence discharge by oem character set, after filling virtual subcarrier, the frequency-domain OFDM symbol formed as follows,
Figure 11 is signaling sequence subcarrier in embodiments of the invention, fixed sequence program subcarrier and virtual subcarrier according to
The arrangement schematic diagram of the two predetermined rules that are staggered.
As shown in figure 11, the signaling sequence that the first half on the left of dotted line is located in figure is placed on odd subcarriers, in figure
The signaling sequence of another half part on the right side of dotted line is placed on even subcarriers, and the first half fixed sequence program on the left of dotted line
Even subcarriers are placed on, the rear part fixed sequence program on the right side of dotted line is placed on odd subcarriers.That is P1_X0,P1_X1,…,
P1_X1023Produce by the second predetermined rule that is staggered, in front half section SC strange carrier wave is put, FC puts even carrier wave, and second half section SC is put
Even carrier wave, FC puts strange carrier wave, and the odd even position of the signaling sequence of Qian Hou half part, fixed sequence program is exchanged.Such fixation
Sequence subcarrierSignaling sequence subcarrierResiding odd even position can exchange, and transmission performance is had no effect.
During filling virtual carrier, the null sequence subcarrier length of left and right sides filling can also be different, but should not differ
It is many.
Continue with the specific embodiment for providing the frequency domain symbol by the second predetermined rule optimization generation that is staggered.By
The frequency-domain OFDM symbol that the two predetermined rules that are staggered are generated is comprised the steps of：
(21st) fixed sequence program generation step, the fixed sequence program generation step and phase in (11st) fixed sequence program generation step
Together, only fixed sequence program subcarrier radian value ωnValue determined by the second predetermined fixed subcarrier radian value table；Wherein,
Second predetermined fixed subcarrier radian value table is by as shown in table 6 below：
Table 6 fixes subcarrier radian value table (by the second predetermined rule optimization that is staggered)
(22nd) signaling sequence generation step, the signaling sequence generation step and (12nd) signaling sequence generation step phase
Together,
(23rd) arrangement filling step, the signaling sequence and fixed sequence program by (21st) step and obtained by (22nd) step
After being occasionally very staggered again by odd even, after left and right sides filling zero carrier, frequency-domain OFDM symbol is formed as follows,
For leading symbol is strengthened, the structure of the time-domain OFDM symbol of two time domain main running signal is except comprising above-mentioned power
Profit is required outside the frequency-domain OFDM symbol generation step of any one in 4 or claim 5, in addition, two time-domain OFDM symbols
Structure can also meet at least one of any three below predetermined association rule：
First predetermined association rule：The respective signaling sequence collection of two time-domain OFDM symbols takes identical.Such as by above-mentioned
If the bit of single symbol transmission 10, so total transmission capacity is 20 bits.
Second predetermined association rule：The fixed sequence program of second time-domain OFDM symbol keeps and first time-domain OFDM symbol
Fixed sequence program it is identical.
3rd predetermined association rule：Effective sub- load comprising fixed sequence program and signaling sequence in second time-domain OFDM symbol
Ripple position is that effective the overall of sub-carrier positions moving to left or moving to right in first time-domain OFDM symbol, and shift value is generally controlled
System is in the range of 0-5.
It is relatively overall that Figure 12 and Figure 13 are that two time domain main running signals that shift value is 1 and 2 are carried out with predetermined association rule
The schematic diagram of displacement.
The generation preferred embodiment for strengthening the frequency domain symbol of A1 and A2 in leading symbol is as follows：
The main body of first symbol A1 and the previously described common leading character generated by the second predetermined rule that is staggered
Number frequency domain symbol it is identical, FC with SC sequences and frequency domain putting position and filling zero carrier it is identical.
The main body of second symbol A2 and the previously described common leading character generated by the second predetermined rule that is staggered
Number FC with SC sequences it is identical, and effective sub-carrier positions of A2 integrally move to left one for A1.I.e.
Figure 14 is the schematic flow sheet of the specific embodiment of the method for reseptance of the leading symbol of the present invention.
As shown in figure 14, the method for reseptance of leading symbol comprises the steps in the present embodiment：
Step S2-1：The physical frame to receiving is processed to obtain baseband signal；
Step S2-2：Before judging the above-mentioned common leading symbol received with the presence or absence of expectation in the baseband signal or strengthening
Lead symbol；
Step S2-3：In the case of being to be in above-mentioned judged result, position of the leading symbol in physical frame is determined simultaneously
Solve the signaling information entrained by the leading symbol.
Specifically, as described in step S2-1, the physical frame to receiving is processed to obtain baseband signal.Generally connect
The signal that receiving end is received is zero intermediate frequency signals, it is therefore desirable to first carries out analog-to-digital conversion to it to obtain data signal, then carries out
Baseband signal is obtained after the process such as filtering, down-sampling.If it should be noted that what receiving terminal received is intermediate-freuqncy signal, right
It also needs to carry out frequency spectrum shift after analog-to-digital conversion process, is then filtered again, down-sampling etc. obtains base band after processing
Signal.
As described in step S2-2, judge in the baseband signal with the presence or absence of expect receive above-mentioned common leading symbol or
Person strengthens leading symbol, specifically includes situations below.
In the present embodiment, if known transmitting terminal is only possible to send common leading symbol, and it is leading to send reinforcement
In the case of symbol, judge to comprise the steps with the presence or absence of the common leading symbol for expecting to receive in the baseband signal：
Step S2-21A：According to C sections, the process between any two of A sections and B sections in the common leading symbol for expecting to receive
Relation and/or modulation relation, carry out carrying out postponing slip auto-correlation after necessary inverse processing and signal demodulation to baseband signal,
Postpone related accumulated value to obtain three；
Step S2-21B：Performed mathematical calculations based on, two or three in the related accumulated value of these three delays,
And peakvalue's checking is carried out to the mathematical operation result；
Step S2-21C：If the result of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect
The common targeting signal for receiving.
Further, step S2-21A can according to the C sections of the first common leading symbol and second common leading symbol,
The predetermined acquisition rule between any two and/or predetermined process rule of A sections and B sections, obtains 2 groups of delay correlation accumulated values, often
3 values of group, and in step S2-21B comprising, two postponed to three of per group in this 2 groups in related accumulated values or
Three perform mathematical calculations, and carry out peakvalue's checking to the mathematical operation result.If wherein first group peakvalue's checking meets default
Condition, it is determined that there is the first the common targeting signal for expecting to receive in the baseband signal；If second group of peakvalue's checking is expired
Foot is pre-conditioned, it is determined that there is second common targeting signal for expecting to receive in the baseband signal；If occurring two groups all
The situation of satisfaction, needs separately to judge, such as can with two groups of peak make an uproar than explicitly being judged.
On this basis, if only possible transmission of known transmitting terminal strengthens leading symbol, and common leading character can not possibly be sent
In the case of number, judge to comprise the steps with the presence or absence of the reinforcement leading symbol for expecting to receive in the baseband signal：
Step S2-22A：According to C sections, the A sections of C-A-B structures and B-C-A structures in the common leading symbol for expecting to receive
And the predetermined acquisition between any two of B sections is regular and/or predetermined process is regular, and necessary correspondingly inverse processing is carried out to baseband signal
And carry out postponing slip auto-correlation after signal demodulation, postponing related accumulated value to obtain six, this six values can actually only by 3
Individual delay autocorrelator is completed；In addition, when the FC sequences of 2 symbols of reinforcement leading symbol adopt identical, before being also obtained
Afterwards the combined and spliced part of the C+A sections of 2 symbols delay correlation accumulated value；
Step S2-22B：The carrying out that the related accumulated value of six delays of step S2-22A has same delay relation is added
Or be added after phase adjustment；The related accumulated value of three different delays is obtained, based on these three related accumulated values and in front and back 2 are postponed
One, two, three or four in the related accumulated value of delay of the combined and spliced part of the C section A sections of individual symbol enters line number
Student movement is calculated, and carries out peakvalue's checking to the mathematical operation result；
Step S2-22C：If the result of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect
The reinforcement targeting signal of reception.
Further, step S2-22A can be according to the first reinforcement leading symbol and the symbol of second reinforcement leading symbol
Internal and intersymbol different delays relation, obtains 2 groups of delay correlation accumulated values, per group of 6 values, and works as reinforcement leading symbol
2 symbols FC sequences using it is identical when, the C+A sections that 2 symbols before and after 2 groups are also obtained postpone related accumulated value；And walk
The carrying out for postponing related accumulated value same delay comprising 6 to per group in this 2 groups in rapid S2-22B is added；2 groups are obtained per group
Related accumulated value comprising 3 different delays；And postpone related accumulated value and in front and back 2 symbols based on three of per group in this 2 groups
Number C section A sections combined and spliced part the related accumulated value of delay in one, two, three or four carry out mathematics fortune
Calculate, and peakvalue's checking is carried out to the mathematical operation result.If wherein first group peakvalue's checking meets pre-conditioned, it is determined that described
Exist in baseband signal and expect that the first for receiving strengthens targeting signal；If second group of peakvalue's checking meets pre-conditioned, really
There is second reinforcement targeting signal for expecting to receive in the fixed baseband signal；If there are two groups of situations about all meeting, need
Separately judge, such as can with two groups of peak make an uproar than explicitly being judged.
If transmitting terminal may send reinforcement leading symbol, it is also possible in the case of sending common leading symbol, then should enter
The common leading symbol detection of the above-mentioned S2-21 of row will also carry out the reinforcement leading symbol detection of above-mentioned S2-22, and here is not repeated
Repeat, due to strengthening the leading symbol necessarily structure comprising common leading symbol, when both meeting pre-conditioned, if strengthening
The peak value of leading symbol better than the peak value of common leading symbol, then is judged as strengthening leading symbol by certain threshold value, is otherwise judged
For common leading symbol.
For the embodiment being previously mentioned, the peak value of common leading symbol obtains block diagram can be as shown in Figure 15 and Figure 16.
Figure 15 is the logic that the peak value of the first the common leading symbol in embodiments of the invention corresponding to three-stage structure CAB is obtained
Schematic diagram.Figure 16 is that the peak value of second common leading symbol in embodiments of the invention corresponding to three-stage structure BCA is obtained
The logical schematic for taking.
Identical part in Figure 15 and Figure 16 only needs to a set of reception resource, it is illustrated that in order to clearly state thus separate.Its
C in middle figure, A, B represent respectively the length of C sections, A sections and B segment signals, and moving average filter can be power normalization
Wave filter.In detail in this figure, C+B=A is met.
The peak value acquisition block diagram for strengthening leading symbol can be as shown in Figure 17 and Figure 18.Figure 17 is in embodiments of the invention
The logical schematic that a kind of peak value for strengthening leading symbol is obtained.Figure 18 is that second reinforcement is leading in embodiments of the invention
The logical schematic that the peak value of symbol is obtained.
Specifically, as described in step S2-3, in the case of being to be in above-mentioned judged result, determine the leading symbol in physics
Position in frame simultaneously solves the signaling information entrained by the leading symbol comprising step in detail below.
Determine that position of the leading symbol in physical frame includes：Based on the result for meeting pre-conditioned peakvalue's checking come
Determine position of the leading symbol in physical frame.
If there is the leading symbol for expecting to receive, determine that leading symbol exists according to the big part value of peak value or maximum
The position occurred in physical frame.Fractional part of frequency offset estimation can also be carried out using the result of peakvalue's checking.
Solve the signaling information entrained by the leading symbol in step S2-3 to comprise the steps：Using leading symbol
All or part of time domain waveform and/or all or part of time domain waveform of the leading symbol obtain after Fourier transformation
Frequency-region signal, to solve the signaling information entrained by the leading symbol.
By the signal comprising signaling sequence subcarrier and signaling sequence t easet ofasubcarriers or the signaling sequence subcarrier collection
Closing corresponding time-domain signal carries out computing, to solve the leading symbol in signaling information by entrained by signaling sequence subcarrier.
Wherein signaling sequence t easet ofasubcarriers are produced based on known signaling sequence set.
Wherein, the signal comprising signaling sequence subcarrier includes：The all or part of time domain of the leading symbol for receiving
Waveform, or 1 or 2 frequency domains that intercepting 1 or 2 main body OFDM symbols are obtained after being fourier transformed from leading symbol
OFDM symbol.Signaling sequence t easet ofasubcarriers be to be filled to effective subcarrier by each signaling sequence in signaling sequence set and
The set of formation.
Specifically, the N of 1 or 2 correspondence ODFM symbol main body is interceptedAThe time-domain signal of length is carried out after Fourier transform
1 obtained or 2 frequency-domain OFDM symbols；Then, zero carrier is removed, 1 for receiving is taken out according to signaling sub-carriers position
Or 2 frequency domain signaling sub-carriers.It is carried out specifically with above-mentioned channel estimation value and known signaling sequence subcarrier collection
Mathematical operation, completes frequency domain decoding function.
For example, if i=0:M-1, M be signaling sub-carriers number, j=0:2P- 1, P make bit number for frequency domain is transmitted, i.e.,
Correspondence signaling sub-carriers collection has 2PIndividual element, and each element correspondence length is the sequence of M, HiFor each signaling sub-carriers pair
The channel estimation value answered, SC_reciFor the frequency domain signaling sub-carriers value for receiving,Concentrate j-th for signaling sequence subcarrier
I-th value in element.ThenTake max (corrj) corresponding
J, that is, obtain the signaling information of frequency-domain transmission.
In other embodiments, said process can also be carried out in time domain, using known signaling sequence subcarrier collection Jing
The time domain signaling waveform corresponding Jing after Fourier inversion of frequency domain symbol of the corresponding length for generating after zero padding in position
Collection directly to obtain multipath accurate location time-domain received signal synchronize it is related, take correlation maximum absolute value that,
The signaling information of frequency-domain transmission can also be solved, is repeated no more here.
Further, receiving terminal can also do integer frequency offset estimation or channel estimation using fixed sequence program, i.e. the present invention
The method of reseptance of leading symbol can also comprise the following steps：
1) according to position of the leading symbol in physical frame is determined, the signal comprising fixed subcarrier is intercepted；
2) by the signal comprising fixed subcarrier and frequency domain stator carrier wave sequence or the frequency domain stator carrier wave sequence
Corresponding time-domain signal carries out computing, to obtain integer frequency offset estimation or channel estimation.
Specifically, the present embodiment comprises the steps：1) according to position of the leading symbol in physical frame is determined, cut
Take the signal comprising fixed subcarrier；2) by the signal comprising fixed subcarrier and frequency domain stator carrier wave sequence or the frequency domain
The corresponding time-domain signal of stator carrier wave sequence carries out computing, to obtain integer frequency offset estimation or channel estimation.
Wherein, the signal comprising fixed subcarrier includes：The all or part of time domain of the leading symbol for receiving
Waveform, or the frequency-domain OFDM symbol obtained after time-domain OFDM symbol is fourier transformed is intercepted from leading symbol.
Receiving terminal is detailed below carries out the two methods of integer frequency offset estimation.
Method 1：
According to position of the leading symbol for detecting in physical frame, the time domain waveform of the leading symbol for receiving is intercepted
All or part.By the way of frequency sweep, i.e., with fixed frequency change step footpath (such as, between correspondence integer frequency offset
Every), the part time domain waveform is modulated after upper different frequency deviation, obtain several time-domain signals：
T is the sampling period, fsFor sample frequency.And known frequency domain fixed sequence program subcarrier carries out the corresponding time domain letter of inverse fourier transform
Number it is A2, using A2 as known signal and each A1yEnter line slip correlation, that A1 of maximum correlation peaks occurs in selectiony, then
The frequency deviation value y modulated to it is integer frequency offset estimation value.
Wherein, the frequency deviation region of antagonism required for swept frequency range correspondence system, such as, need the frequency for resisting positive and negative 500K
Partially, and systematic sampling rate be 9.14M, leading symbol main body be 1K length, then swept frequency range beI.e. [- 57,
57]。
Used correlation can here be repeated no more with FFT and IFFT come equivalent realization in frequency sweep.
Method 2：
Intercepting the time-domain signal of correspondence ODFM symbol main bodys in leading symbol carries out obtaining frequency-domain OFDM after Fourier transform
Symbol, by the frequency-domain OFDM symbol that conversion is obtained the cyclic shift of above-mentioned swept frequency range, and the position by FC on sub-carriers are carried out
Put and in front and back the interval of 2 fixed sequence program subcarriers carry out dot interlace difference multiplication, and with the dot interlace of known fixed sequence subcarrier
Difference multiplied value carries out related operation, obtains a series of correlations, chooses the corresponding cyclic shift of maximum related value, you can corresponding
Obtain that integer frequency offset estimation value can be obtained.
Further, when there is the reinforcement leading symbol for expecting to receive in judging the baseband signal, if strengthening leading
The shift value of the effective sub-carrier positions of symbol is even number, also the time-domain signal of 2 correspondence ODFM symbol main bodys can be carried out into Fourier
The 2 frequency-domain OFDM symbols obtained after leaf transformation, 2 frequency-domain OFDM symbols that conversion is obtained are while carry out above-mentioned swept frequency range
Same loop displacement, each the symbol reception value after displacement and the symbol known fixed sequence sub-carrier values conjugate multiplication, and
The multiplied value of the same sub-carrier positions of 2 symbols is carried out again after conjugate multiplication, by all effective FC of 2 symbol common locations
The conjugate multiplication value of subcarrier is added up, i.e.,J ∈ swept frequency ranges, Ri,1,jFor
Reception value on first symbol frequency domain after shifted j on correspondence FC positions, Ri,2,jAfter shifted j on second symbol frequency domain
Reception value on correspondence FC positions,WithFC on certain subcarrier of respectively first symbol and second symbol
Given value, M is known FC total numbers, so obtains a series of accumulated values corresponding to each cyclic shift value, chooses maximum cumulative
It is worth corresponding cyclic shift, you can accordingly obtain that integer frequency offset estimation value can be obtained.
Using the signal comprising fixed sequence program subcarrier for receiving and known frequency domain fixed sequence program subcarrier and/or its enter
The corresponding time-domain signal of row inverse fourier transform completes channel estimation, equally can select to carry out in time domain and/or enter in frequency domain
OK, will not be described here.
Claims (10)
1. a kind of generation method of leading symbol, it is characterised in that comprise the steps：
Time-domain symbol with three-stage structure is generated based on the resulting time domain main running signal；And
Leading symbol is generated based on time-domain symbol described at least one.
2. the generation method of leading symbol as claimed in claim 1, it is characterised in that：
Wherein, the time-domain symbol with three-stage structure is following any one three-stage structure：
The first described three-stage structure is：The time domain main running signal, generated based on the part of the time domain main running signal before
Sew and the suffix of generation modulated based on the part of the time domain main running signal,
Three-stage structure is described in second：The time domain main running signal, generated based on the part of the time domain main running signal before
Sew and sewing in advance for generation is modulated based on the part of the time domain main running signal.
3. the generation method of leading symbol as claimed in claim 1, it is characterised in that：
Common leading symbol is generated when wherein, based on a time-domain symbol, there are different three-stage structures based at least two
The time-domain symbol when splicing generate strengthen leading symbol.
4. the generation method of leading symbol as claimed in claim 1, it is characterised in that：
Wherein, the time domain main running signal is that the frequency-domain OFDM symbol to predetermined length carries out inverse discrete fourier transform and obtains
Time-domain OFDM symbol.
5. the generation method of leading symbol as claimed in claim 4, it is characterised in that：
Wherein, the frequency-domain OFDM symbol includes virtual subcarrier, signaling sequence subcarrier and fixed sequence program subcarrier,
After arranging according to the predetermined rule that is staggered the signaling sequence subcarrier and the fixed sequence program subcarrier, will
The virtual subnet distribution of carriers is in its both sides.
6. the generation method of leading symbol as claimed in claim 5, it is characterised in that：
Wherein, the predetermined rule that is staggered is comprising any one in following two rules：
The first predetermined rule that is staggered：Very staggeredly arranged in oem character set or idol；And
The second predetermined rule that is staggered：A part of signaling sequence is placed on odd subcarriers, another part signaling sequence is placed on
Even subcarriers, and a part of fixed sequence program is placed on odd subcarriers, another part fixed sequence program is placed on even subcarriers.
7. the generation method of leading symbol as claimed in claim 2, it is characterised in that：
In the prefix, the suffix or the generation step sewed in advance, comprise the steps of：
Using the time domain main running signal as Part I, the least significant end of the neat Part I takes out according to the predetermined rule that obtains
A part, the front portion of the Part I is processed and copied to according to the first predetermined process rule come generate Part III so as to
As the prefix, meanwhile, a part is taken out according to the predetermined rule that obtains from the rear portion of the Part I, it is predetermined according to second
Process rule to be processed and copied to the rear portion of the Part I or process and copy to the front portion of the prefix generating
Part II is so as to mutually should be used as respectively the suffix or described sew in advance.
8. the generation method of leading symbol as claimed in claim 7, it is characterised in that
Wherein, the predetermined acquisition rule includes：
If LenBFor the length of the Part II, LenCFor the length of the Part III, LenB≤LenC, N1 is separately set to select
The sampled point sequence number of the corresponding Part I of starting point of the Part II is copied to, N2 is copied to described second for selection
The sampled point sequence number of the corresponding Part I of partial terminal, then meet below equation：N2=N1+LenB-1。
9. the generation method of leading symbol as claimed in claim 7, it is characterised in that：
Wherein, the first predetermined process rule includes：Direct copying；Or
An identical fixed coefficient or predetermined difference coefficient are multiplied by each sampled signal in taken out part,
The second predetermined process rule includes：Process is modulated when first predetermined process rule is direct copying；
Or
When first predetermined process rule by each sampled signal in taking-up part be multiplied by an identical fixed coefficient or
Also being multiplied by after corresponding coefficient during predetermined difference coefficient carries out modulation treatment.
10. a kind of method of reseptance of leading symbol, it is characterised in that comprise the steps：
Step S2-1：Physical frame to receiving is processed to obtain baseband signal；
Step S2-2：Judge in the baseband signal with the presence or absence of the leading symbol described in the claim 1 for expecting to receive；
Step S2-3：When being judged as YES, determine position of the leading symbol in physical frame and solve entrained by the leading symbol
Signaling information.
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Also Published As
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| CN105743624B (en) | 2019-02-26 |
| CN106685881A (en) | 2017-05-17 |
| CN106685626A (en) | 2017-05-17 |
| CN109617846B (en) | 2022-01-28 |
| CN105743624A (en) | 2016-07-06 |
| CN109617846A (en) | 2019-04-12 |
| CN106685882A (en) | 2017-05-17 |
| CN106850487A (en) | 2017-06-13 |
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