CN106850487A - The method of reseptance of leading symbol - Google Patents

The method of reseptance of leading symbol Download PDF

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Publication number
CN106850487A
CN106850487A CN201611190980.1A CN201611190980A CN106850487A CN 106850487 A CN106850487 A CN 106850487A CN 201611190980 A CN201611190980 A CN 201611190980A CN 106850487 A CN106850487 A CN 106850487A
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China
Prior art keywords
leading symbol
symbol
signal
time domain
leading
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Inventor
张文军
邢观斌
黄戈
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Shanghai National Engineering Research Center of Digital Television Co Ltd
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Shanghai National Engineering Research Center of Digital Television Co Ltd
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Priority to CN201611190980.1A priority Critical patent/CN106850487A/en
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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
    • H04L27/2647—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
    • 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
    • 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
    • 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

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

The invention provides a kind of method of reseptance of leading symbol, the physical frame to receiving is processed to obtain baseband signal；Judge the leading symbol received with the presence or absence of expectation in baseband signal；When being judged as YES, determine the leading symbol in physical frame position and solve the leading symbol carrying signaling information, wherein, leading symbol by least one have following any one three-stage structure time-domain symbol generate, wherein, the first is：Prefix and the part based on the time domain main running signal that time domain main running signal, the part based on the time domain main running signal are generated modulate the suffix of generation, are for second：The prefix and the part based on the time domain main running signal that time domain main running signal, the part based on the time domain main running signal are generated are modulated the advanced of generation and are sewed, in solving current DVB_T2 standards and other standards, relevant detection is not applied for, and there is the problem of probability of failure in the detection of low complex degree receiving algorithm under complex frequency Selective Fading Channel.

Description

The method of reseptance of leading symbol
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 transmitted by transmitting terminal are correctly 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, be carried out accurately with to carrier wave frequency deviation Estimation and correction.
At present, realize that transmitting terminal and the synchronous method of destination time are substantially come real based on leading symbol 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 occur in each physical frame a P1 symbol or it is continuous there are multiple P1 symbols, P1 is accorded with Number purposes include：
1) whether receiving terminal is rapidly detected with determine to transmit in channel is the signal expecting to receive；
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, frequency and Timing Synchronization is reached after being used to compensate；
4) emergency alarm or broadcast system wake up.
The P1 Design of Symbols based on CAB spatial structures is proposed in DVB_T2 standards, above-mentioned functions are preferably realized.But It is still have some to limit on low complex degree receiving algorithm.For example, in 1024,542 or 482 multipath long letters of symbol 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 multipath long, DBPSK differential decodings are likely to Can fail.Being additionally, since in DVB_T2 spatial structures does not have 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
During the problem that the present invention is solved is current DVB_T2 standards and other standards, do not have the present invention in DVB_T2 spatial structures During the problem of solution is current DVB_T2 standards and other standards, there is no Cyclic Prefix in DVB_T2 spatial structures, it is impossible to be applicable 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 the embodiment of the invention provides, 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 The prefix and the rear portion based on the time domain main running signal that signal, the rear portion based on the time domain main running signal are generated are modulated The suffix of generation, second three-stage structure be：Before time domain main running signal, the rear portion based on the time domain main running signal are generated Sew and the rear portion based on the time domain main running signal is modulated the advanced of generation and sewed, generated when based on a time-domain symbol general Logical leading symbol, when having the time-domain symbol of different three-stage structures based on two, leading symbol is strengthened in splicing generation.
Alternatively, time domain main running signal is to carry out inverse discrete fourier transform to the frequency-domain OFDM symbol of predetermined length and obtain 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 includes 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 advanced generation step sewed, 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 is advised according to the first predetermined process The front portion of the Part I is then processed and is copied 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 and generate Part II so as to mutually should be used as suffix respectively or sew in advance.
Alternatively, wherein, the predetermined rule that obtains includes：If LenBIt is the length of Part II, LenCIt is the length of Part III Degree, LenB≤LenC, the sampled point sequence number that N1 is copied to the corresponding Part I of starting point of Part II as selection is separately set, 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 makes a reservation for different coefficients, and the second predetermined process rule includes：When the first predetermined process Treatment is modulated when rule is for direct copying；Or when the first predetermined process rule for institute taking-up part in each sample believe Number it is multiplied by an identical fixed coefficient or makes a reservation for carry out modulation treatment after being also multiplied by corresponding coefficient during different coefficients.
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 broadcasted for identifying emergent.
Alternatively, wherein, strengthen in two different time domain symbols of leading symbol, two time domain main running signal is different, And the three-stage structure of use 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 following 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 following 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 treatment 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 treatment obtain baseband signal.
Alternatively, in the case of the only possible common leading symbol of transmission of known transmitting terminal, judge whether deposited in baseband signal Comprise the following steps in the common leading symbol for expecting to receive：Step S2-21A：Received 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 Treatment rule, carries out postponing to slide auto-correlation, to obtain three after carrying out baseband signal correspondingly inverse processing and signal demodulation 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, judge in baseband signal whether Comprise the following steps in the presence of the reinforcement leading symbol for expecting to receive：Step S2-22A：According to the reinforcement leading symbol for expecting to receive In the first three-stage structure and second Part III of three-stage structure, Part I and Part II between any two predetermined Rule and/or predetermined process rule are obtained, delay cunning is carried out after correspondingly inverse processing and signal demodulation are carried out to baseband signal Dynamic auto-correlation, related accumulated value is postponed to obtain six, and this six value reality are obtained by 3 delay correlators, wherein, work as reinforcement When two fixed sequence programs of symbol of leading symbol use identical, the Part III and first of former and later two symbols is also can obtain 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 three related accumulated values of 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 At least one of correlation accumulated value performs mathematical calculations late, 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 determine position of the leading symbol in physical frame, if in the presence of the leading symbol for expecting to receive, it is big according to peak value Residing partial value or maximum determine the position or carry out fractional part of frequency offset estimation that leading symbol occurs in physical frame.
Alternatively, using leading symbol all or part of time domain waveform and/or the leading symbol all or part when Domain waveform by the frequency-region signal that is obtained after Fourier transformation, with solve the signaling information entrained by the leading symbol include it is 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 signaling information in the leading symbol as entrained by signaling sequence subcarrier, wherein Signaling sequence t easet ofasubcarriers are based on the set of known signaling sequence and produce.
Alternatively, the method for reseptance of the leading symbol in the embodiment of the present invention, it is characterised in that also comprise the following steps：1) According to position of the leading symbol in physical frame is determined, interception includes the signal for fixing subcarrier；2) this is included into 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：
According to embodiments of the present invention provide leading symbol generation method 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 circulating prefix-length based on above-mentioned interception signal generation modulated signal 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 selection transmission one of robustness or two symbols work as biography respectively as common leading symbol or reinforcement leading symbol It is different by designing two kinds based on same OFDM symbol main body when sending a symbol for three-stage structure as leading symbol Three-stage structure, carrys out identifying emergent broadcast；When two symbols of three-stage structure are transmitted as leading symbol, two OFDM symbol Main body is different, and the three-stage structure for using is also just different, on this basis, is arranged by two sequencings of three-stage structure 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 small inclined estimation failure problem, further, leading symbol of the invention using three sections have part identical content knots Structure, it is ensured that in receiving terminal using the related peak value that may be significantly of delay, also, during the leading symbol is generated, Designing the modulated signal of time domain main body number can avoid receiving terminal from being subject to continuous wave CO_2 laser or mono-tone interference, or occurs 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.
Brief description of the drawings
Fig. 1 is the schematic flow sheet of the embodiment of the generation method of leading symbol of the 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 the schematic diagram based on the first common leading symbol acquisition treatment in embodiments of the invention；
Fig. 5 is the schematic diagram for obtaining treatment in embodiments of the invention based on second common leading symbol；
Fig. 6 is that the first strengthens two schematic diagrames of three-stage structure in leading symbol in embodiments of the invention；
Fig. 7 is to strengthen two schematic diagrames of three-stage structure in leading symbol second in embodiments of the invention；
Fig. 8 is the schematic diagram based on the first reinforcement leading symbol acquisition treatment in embodiments of the invention；
Fig. 9 is to strengthen the schematic diagram that leading symbol obtains treatment based on second in embodiments of the invention；
Figure 10 be in embodiments of the invention signaling sequence subcarrier, fixed sequence program subcarrier and virtual subcarrier according to The arrangement schematic diagram of the one predetermined rule that is staggered；
Figure 11 be in embodiments of the invention signaling sequence subcarrier, fixed sequence program subcarrier and virtual subcarrier according to The arrangement schematic diagram of the two predetermined rules that are staggered；
Figure 12 is to strengthen two time domain main running signals in leading symbol in embodiments of the invention with predetermined association rule In shift value 1 carry out the arrangement schematic diagram of relative integral shift；
Figure 13 is to strengthen two time domain main running signals in leading symbol in embodiments of the invention with predetermined association rule 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 leading symbol of the invention；
Figure 15 is that the peak value of the first the common leading symbol for corresponding to three-stage structure CAB in embodiments of the invention is obtained The logical schematic for taking；
Figure 16 is that the peak value of second common leading symbol for corresponding to three-stage structure BCA in embodiments of the invention is obtained The logical schematic for taking；
Figure 17 is the logical schematic of peak value acquisition of the first reinforcement leading symbol in embodiments of the invention；And
Figure 18 is second logical schematic of the peak value acquisition of reinforcement leading symbol in embodiments of the invention.
Specific embodiment
Inventor has found in current DVB_T2 standards and other standards do not have 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.
Regarding to the issue above, inventor is by research, there is provided the generation method and method of reseptance of a kind of leading symbol, solution The problem of noncoherent detection of having determined hydraulic performance decline, performance and Timing Synchronization performance are estimated with good fractional part of frequency offset, may be used also The problem for avoiding the small 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 it is understandable, below in conjunction with the accompanying drawings to this hair Bright specific embodiment is described in detail.
Fig. 1 is the schematic flow sheet of the embodiment of the generation method of leading symbol of the invention.As shown in figure 1, this implementation The generation method of leading symbol comprises the following 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：Before time domain main running signal, the rear portion based on the time domain main running signal are generated Sew and the suffix of generation is modulated at the rear portion based on the time domain main running signal, second three-stage structure is：Time domain main body is believed Number, the prefix that is generated of the rear portion based on the time domain main running signal and the rear portion based on the time domain main running signal modulate life Into advanced sew.
When generating leading symbol when based on a time-domain symbol, the leading symbol is common leading symbol；When based on two When splicing generation 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, taken 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 generates Part II (in figure with B indicate) so as to mutually should be used as suffix respectively or sew in advance, so that, generate respectively B as shown in Figure 2 is as the first common leading symbol (CAB structures) and B of suffix 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；Work as hair 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.
Carried out after on obtaining out Part III, Part II from Part I for treatment specific rules, first is pre- Fixed treatment rule includes：Direct copying；Or an identical fixed coefficient is multiplied by each sampled signal in taken out part Or make a reservation for different coefficients.Second predetermined process rule includes：Place is modulated when the first predetermined process rule is for 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 different coefficients.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 that when being 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 the schematic diagram based on the first common leading symbol acquisition treatment in embodiments of the invention.
C sections is A section of direct copying in the present embodiment, and B section is A sections of modulated signal section, 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 treatment 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 no more than C, that is, selecting the scope of the part A to modulated signal section B will not surpass Go out scope of the interception as the part A of prefix C.Preferably, the length sum of the length of B and C is the length of A.
If NAIt is the length of A, if LenCIt is the length of C, LenBIt is the length of modulated signal section B.If the sampled point sequence number of A It is 0,1 ... NA- 1. set the sampled point that N1 is copied to the corresponding Part I A of starting point of modulated signal section Part II B as selection Sequence number, N2 is the sampled point sequence number of the corresponding Part I A of terminal that selection is copied to modulated signal section Part II B.Wherein,
N2=N1+LenB-1
Generally, that Part II B sections is implemented is modulated to frequency modulation, modulation M sequence or other sequences etc., in this implementation 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 i.e. 1/N in subcarrier in frequency domain interval of time-domain OFDM symbol can be chosen forAT, wherein T is sampling period, NAIt is the length of time-domain OFDM symbol, in this example, NAIt is 1024, takes fSH=1/1024T.And frequency modulation First phase can be arbitrarily selected, in order that correlation peak is sharp, fSHIt is 1/ (Len that can also selectBT)。
As shown in figure 4, NA=1024；LenC=520, LenB=504, N1=520.Now CA sections includes identical content Autocorrelation lags are NA, the CB sections of autocorrelation lags comprising identical content are NA+LenB, and AB section includes identical content from phase Close and postpone to be LenB。
Fig. 5 is the schematic diagram for obtaining treatment in embodiments of the invention based on second common leading symbol.
Similarly, the time-domain expression of second common leading symbol is, it is noted that in order that obtain 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 includes identical content Autocorrelation lags are NA, the BC sections of autocorrelation lags comprising identical content are LenB, and the BA sections of auto-correlation comprising identical content is prolonged It is late NA+LenB。
Fig. 6 is that the first strengthens two schematic diagrames of three-stage structure in leading symbol in embodiment.Fig. 7 is in embodiment Two kinds are strengthened two schematic diagrames of three-stage structure in leading symbol.
Respectively as shown in Figure 6 and Figure 7, strengthen in two different time domain symbols of leading symbol, two time domain main body is believed Number difference, and the three-stage structure for using is also different, is formed respectively as in Fig. 6 by two different successively sequences of 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, it is the twice of general leading symbol or close to twice that so strengthen leading symbol can transmit the capacity of signaling.
The detection of common leading symbol obtains peak value using CB sections, CA sections and BA sections of delay auto-correlation, adds using During strong leading symbol, in order that 2 autocorrelation values of symbol can be added, obtain more robust performance, then 2 symbols are each Parameter N1 (i.e. N1 is the sampled point sequence number of the corresponding A of starting point that selection is copied to modulated signal section B) need to meet certain and close System, if first N1 of symbol is N1_1, second N1 of symbol is N1_2, it is necessary to meet N1_1+N1_2=NA.And it is if right If the modulation of B sections of use is frequency modulation, frequency deviation value wants contrast.
The symbol of C-A-B structures is represented with sequence number 1, the symbol of B-C-A structures is represented with sequence number 2.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 the schematic diagram based on the first reinforcement leading symbol acquisition treatment in embodiments of the invention.
As shown in figure 8, a preferred embodiment is, 2 C of general symbol sections, A sections of, N identical with B segment lengthA= 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 treatment 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 after inverse fourier transform by frequency-domain OFDM symbol and obtained.
If P1_X is corresponding frequency-domain OFDM symbol, P1_XiTime-domain OFDM symbol is obtained after making 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 comprising following two rules in it is any It is a kind of：
The first predetermined rule that is staggered：Staggeredly arranged in oem character set or idol are strange；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 as pilot tone Rule discharge, realizes that the predetermined rule that is staggered of channel estimation more convenient second then needs part SC sequences to be placed on odd number Carrier wave, remaining SC sequences are placed on even subcarriers；Need part FC sequences to be placed on odd subcarriers simultaneously, residual F C sequences are put In even subcarriers, it thus is avoided that FC or SC are all placed on even or odd subcarrier, can be all under some special multipaths Decline is fallen, and such discharge can improve the complexity ignored to channel estimation, therefore is 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 is 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 be in embodiments of the invention signaling sequence subcarrier, 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：Filled 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, L=P=353, then G=318, both sides are respectively filled 159 null sequences and are carried Ripple.
Comprised the steps of by the described first predetermined frequency-domain OFDM symbol for being staggered rule generation：
(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, R is 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 distinguishing using the positive and negative of correlation Positive sequence or antitone sequence, i.e., transmit 10bit signaling informations altogether, and 512 signaling sequences can be further divided into 4 groups, every group again 128 signaling sequences, every group of 128 signaling sequences generation sub-step is as follows：
1st sub-step：Generation consensus sequence zciN (), it is Zadoff-Chu sequence zc (n) that length is N：
2nd sub-step:By copying zc twiceiN it is 2N's that () produces length
3rd sub-step:FromIn certain specific original position kiIntercepted length is 353 sequence, produces SCi(n)：
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 values, 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 values, 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, its N values, 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 and letter obtained by (11) step and (12) step Make sequence be discharged by oem character set, after filling virtual subcarrier, the frequency-domain OFDM symbol formed as follows,
Figure 11 be in embodiments of the invention signaling sequence subcarrier, 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_X1023Produced by the second predetermined rule that is staggered, strange carrier wave is put in front half section SC, 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 front and rear half part, fixed sequence program is exchanged.Such fixation Sequence subcarrierSignaling sequence subcarrierResiding odd even position can be exchanged, 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 two predetermined frequency-domain OFDM symbols for being staggered rule generation are 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, by signaling sequence and fixed sequence program obtained by (21st) step and (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 strengthening leading symbol, 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：Two respective signaling sequence collection of time-domain OFDM symbol take 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：Second fixed sequence program of 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 effectively 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 by the second predetermined rule generation that is staggered Number frequency domain symbol it is identical, FC with SC sequences and frequency domain putting position and filling zero carrier are identical.
The main body of second symbol A2 and the previously described common leading character by the second predetermined rule generation 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 leading symbol of the invention.
As shown in figure 14, the method for reseptance of leading symbol comprises the following steps in the present embodiment：
Step S2-1：The physical frame to receiving is processed to obtain baseband signal；
Step S2-2：Before judging in the baseband signal with the presence or absence of the above-mentioned common leading symbol for expecting to receive or strengthening Lead symbol；
Step S2-3：It is in the case of being, to determine position of the leading symbol in physical frame simultaneously in above-mentioned judged result 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 treatment such as filtering, down-sampling.If it should be noted that what receiving terminal received is intermediate-freuqncy signal, right It carries out frequency spectrum shift by being also needed to after analog-to-digital conversion process, is then filtered again, obtains base band after the treatment such as down-sampling Signal.
As described in step S2-2, judge in the baseband signal with the presence or absence of the above-mentioned common leading symbol for expecting to receive 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 following 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, A sections and B sections for the treatment of between any two in the common leading symbol for expecting to receive Relation and/or modulation relation, carry out postponing to slide auto-correlation after carrying out baseband signal necessary inverse processing and signal demodulation, 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 first common leading symbol and second the C of common leading symbol sections, A sections and B sections of the rule of predetermined acquisition between any two and/or predetermined process rule, obtains 2 groups of delay correlation accumulated values, often 3 values of group, and in step S2-21B comprising, two postponed to three of every 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, it is necessary to separately judge, such as can with two groups of peak make an uproar than explicitly 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 following 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, A sections of C-A-B structures and B-C-A structures in the common leading symbol for expecting to receive And B sections of predetermined acquisition rule and/or predetermined process rule between any two, necessary correspondingly inverse processing is carried out to baseband signal And carry out postponing to slide 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 use identical, before also can obtain Afterwards 2 C+A of symbol sections of combined and spliced part delay correlation accumulated value；
Step S2-22B：The carrying out that postponing related accumulated value by six of step S2-22A has same delay relation is added Or be added after phase adjustment；Three related accumulated values of different delays are obtained, based on the related accumulated value and front and rear 2 of these three delays One, two, three or four in the related accumulated value of delay of the combined and spliced part of C sections A sections of individual symbol is entered 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, every group of 6 values, and work as reinforcement leading symbol 2 symbols FC sequences using it is identical when, also can obtain 2 groups before and after 2 the C+A of symbol section postpone correlation accumulated values；And step The carrying out for postponing related accumulated value same delay comprising 6 to every group in this 2 groups in rapid S2-22B is added；Obtain 2 groups every group Comprising 3 related accumulated values of different delays；And postpone related accumulated value and front and rear 2 symbols based on three of every group in this 2 groups Number C sections 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 occur two groups of situations about all meeting, it is necessary to Separately judge, such as can with two groups of peak make an uproar than explicitly 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, be not repeated herein Repeat, due to strengthening the leading symbol necessarily structure comprising common leading symbol, when both meeting pre-conditioned, if strengthening Peak value of the peak value of leading symbol by certain threshold value better than common leading symbol, then be judged as strengthening leading symbol, otherwise judges It is 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 obtains of peak value of the first the common leading symbol for corresponding to three-stage structure CAB in embodiments of the invention Schematic diagram.Figure 16 is that the peak value of second common leading symbol for corresponding to three-stage structure BCA in embodiments of the invention 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 separated to clearly state.Its C in middle figure, A, B represent the length of C sections, A sections and B segment signals respectively, 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, it is in the case of being, to determine the leading symbol in physics in above-mentioned judged result as described in step S2-3 Position in frame simultaneously solves the signaling information entrained by the leading symbol and includes 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 in the presence of the leading symbol for expecting to receive, determining 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.
The signaling information solved entrained by the leading symbol in the step S2-3 comprises the following steps：Using leading symbol All or part of time domain waveform and/or the leading symbol all or part of time domain waveform by being obtained 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 signaling information in the leading symbol as entrained by signaling sequence subcarrier. Wherein signaling sequence t easet ofasubcarriers are based on known signaling sequence set generation.
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 interception 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, 1 or 2 N of correspondence ODFM symbol main bodys is interceptedAAfter the time-domain signal of length carries out 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, setting i=0:M-1, M are 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, HiIt is each signaling sub-carriers pair The channel estimation value answered, SC_reciIt is the frequency domain signaling sub-carriers value for receiving,For signaling sequence subcarrier is concentrated j-th 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, be passed through using known signaling sequence subcarrier collection The time domain signaling waveform corresponding after Fourier inversion of frequency domain symbol of the corresponding length for being generated after zero padding in position Collection directly synchronizes related to the time-domain received signal for obtaining multipath accurate location, takes that of correlation maximum absolute value, 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, interception includes the signal for fixing subcarrier；
2) this is included the signal and frequency domain stator carrier wave sequence or the frequency domain stator carrier wave sequence of fixed subcarrier Corresponding time-domain signal carries out computing, to obtain integer frequency offset estimation or channel estimation.
Specifically, the present embodiment comprises the following steps：1) according to position of the leading symbol in physical frame is determined, cut Take the signal comprising fixed subcarrier；2) this is included the signal and frequency domain stator carrier wave sequence or the frequency domain of fixed subcarrier 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：
The time domain ripple of the leading symbol received according to position of the leading symbol for detecting in physical frame, interception The all or part of shape.By the way of frequency sweep, i.e., with fixed frequency change step footpath (such as, correspondence integral multiple Frequency deviation is spaced), after the part time domain waveform is modulated into upper different frequency deviation, obtain several time-domain signals：T is sampling period, fsIt is sample frequency.And known frequency domain fixed sequence program is carried Ripple carries out the corresponding time-domain signal of inverse fourier transform for A2, using A2 as known signal and each A1yEnter line slip related, choosing Take out that A1 of existing maximum correlation peaksy, then the frequency deviation value y for being modulated to it as integer frequency offset estimation values.
Wherein, the frequency deviation region of confrontation required for swept frequency range correspondence system, such as, it is necessary to resist the frequency of 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：
The time-domain signal of correspondence ODFM symbol main bodys obtains frequency-domain OFDM after carrying out Fourier transform in interception leading symbol Symbol, will convert the frequency-domain OFDM symbol for obtaining carries out the cyclic shift of above-mentioned swept frequency range, and the position by FC on sub-carriers Put and the interval of front and rear 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, will convert the 2 frequency-domain OFDM symbols for obtaining while carrying out above-mentioned swept frequency range Same loop displacement, each symbol reception value after displacement and the symbol known fixed sequence sub-carrier values conjugate multiplication, and After the multiplied value of 2 same sub-carrier positions of symbol is carried out into conjugate multiplication again, by 2 all effective FC of symbol common location 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 respectively first symbol and second certain subcarrier of 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, can equally select to be carried out in time domain and/or entered in frequency domain OK, will not be repeated here.

Claims (10)

1. a kind of method of reseptance of leading symbol, it is characterised in that comprise the following steps：
Step S2-1：Physical frame to receiving is processed to obtain baseband signal；
Step S2-2：Judge the leading symbol received with the presence or absence of expectation in the baseband signal；
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,
Wherein, the leading symbol is generated by least one time-domain symbol with following any one three-stage structure,
Wherein, the first described three-stage structure is：The time domain main running signal, the part based on the time domain main running signal are generated Prefix and the part based on the time domain main running signal modulate the suffix of generation,
Three-stage structure is described in second：Before the time domain main running signal, the part based on the time domain main running signal are generated Sew and the part based on the time domain main running signal is modulated the advanced of generation and sewed.
2. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that
In the case of the only possible transmission leading symbol of known transmitting terminal, judge to be connect with the presence or absence of expectation in the baseband signal The leading symbol received comprises the following steps：
Step S2-21A：According to the super prefix part in the leading symbol for expecting to receive, time domain main part and prefix part Predetermined acquisition rule and/or predetermined process rule between any two, correspondingly inverse processing and signal solution are carried out to baseband signal Carry out postponing to slide auto-correlation after tune, related accumulated value is postponed to obtain three；
Step S2-21B：Performed mathematical calculations based at least one of related accumulated value of these three delays, and the mathematics is transported Calculating result carries out peakvalue's checking；And
Step S2-21C：If the result of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect to receive Leading symbol.
3. the method for reseptance of leading symbol as claimed in claim 2, it is characterised in that
Wherein, the step S2-21A can be according to the first three-stage structure time-domain symbol and second three-stage structure time-domain symbol Super prefix part, time domain main part and prefix part different disposal relation and/or modulation relation, obtain 2 groups of delays related Accumulated value, every group of 3 values,
Also, postpone related adding up comprising three to every group in 2 groups of delays correlation accumulated value in the step S2-21B At least one performs mathematical calculations in value, and carries out peakvalue's checking to the mathematical operation result,
Wherein, if the result of first group of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect to receive The first three-stage structure time-domain symbol；
If the result of second group of peakvalue's checking meets pre-conditioned, it is determined that there is expect to receive second in the baseband signal Plant three-stage structure time-domain symbol；
If two groups of result all meets pre-conditioned, further with two groups of peaks make an uproar than explicitly judged.
4. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that.
In the case of the only possible transmission leading symbol of known transmitting terminal, judge to whether there is expectation in the baseband signal The leading symbol for receiving comprises the following steps：
Step S2-22A：According to the first described three-stage structure and three-stage structure described in second in the leading symbol for expecting to receive Super prefix part, time domain main part and prefix part between any two predetermined acquisition rule and/or predetermined process rule, Carry out postponing to slide auto-correlation after carrying out baseband signal correspondingly inverse processing and signal demodulation, correlation is postponed to obtain six Accumulated value, it is actual to be obtained by 3 delay correlators, wherein, when two fixed sequence programs of symbol of leading symbol use identical, The delay that also can obtain the combined and spliced part of the super prefix part and time domain main part of former and later two symbols is related cumulative Value；
Step S2-22B：The carrying out that postponing related accumulated value by six of the step S2-22A has same delay relation is added Or be added after phase adjustment, three related accumulated values of different delays are obtained, based on these three related accumulated values of delay and front and rear In the related accumulated value of delay of the super prefix part of two symbols and the combined and spliced part of time domain main part at least one It is individual to perform mathematical calculations, and peakvalue's checking is carried out 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 to receive Reinforcement leading symbol.
5. the method for reseptance of leading symbol as claimed in claim 4, it is characterised in that.
Step S2-22A can be according to inside the first leading symbol and second symbol of leading symbol and intersymbol not co-extensive Slow relation, obtains the fixed sequence program use of 2 groups of delay correlation accumulated values, every group of 6 values, and two symbols when leading symbol When identical, the section of the super prefix part of also available 2 groups of former and later two symbols and the combined and spliced part of time domain main part Postpone related accumulated value, also, postpone related accumulated value same delay comprising 6 to every group in this 2 groups in step S2-22B Carrying out be added；Obtain 2 groups every group and include 3 related accumulated values of different delays；And based on every group in this 2 groups of three delays Related accumulated value is related to the delay of the super prefix part of former and later two symbols and the combined and spliced part of time domain main part At least one of accumulated value performs mathematical calculations, and carries out peakvalue's checking to the mathematical operation result,
Wherein, if first group of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect the described of reception The first strengthens leading symbol；
If second group of peakvalue's checking meets pre-conditioned, it is determined that there is expect to receive described second in the baseband signal Strengthen leading symbol；
If two groups of situations about all meeting, need further with two groups of peaks make an uproar than explicitly judged.
6. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that.
Transmitting terminal may send reinforcement leading symbol be likely to send common leading symbol in the case of, then should carry out as follows Common leading symbol detecting step will also carry out following leading symbol detecting step：
Common leading symbol detecting step：
Step S2-21A：According to as described in claim 7 expect receive common leading symbol in super prefix part, when Domain main part and prefix part predetermined acquisition rule and/or predetermined process rule between any two, are carried out to baseband signal Correspondingly carry out postponing to slide auto-correlation after inverse processing and signal demodulation, related accumulated value is postponed to obtain three；
Step S2-21B：Performed mathematical calculations based at least one of related accumulated value of these three delays, and the mathematics is transported Calculating result carries out peakvalue's checking；And
Step S2-21C：If the result of peakvalue's checking meets pre-conditioned, it is determined that exist in the baseband signal and expect to receive Leading symbol,
Strengthen leading symbol detecting step：
Step S2-22A：According to the first described three-stage structure and three-stage structure described in second in the leading symbol for expecting to receive Super prefix part, time domain main part and prefix part between any two predetermined acquisition rule and/or predetermined process rule, Carry out postponing to slide auto-correlation after carrying out baseband signal correspondingly inverse processing and signal demodulation, correlation is postponed to obtain six Accumulated value, wherein, when two fixed sequence programs of symbol of leading symbol use identical, also can obtain the super of former and later two symbols The delay correlation accumulated value of the combined and spliced part of prefix part and time domain main part；
Step S2-22B：The carrying out that postponing related accumulated value by six of the step S122A has same delay relation is added Or be added after phase adjustment, three related accumulated values of different delays are obtained, based on these three related accumulated values of delay and front and rear In the related accumulated value of delay of the super prefix part of two symbols and the combined and spliced part of time domain main part at least one It is individual to perform mathematical calculations, and peakvalue's checking is carried out 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 to receive The reinforcement leading symbol,
Wherein, when the result of both peakvalue's checkings all meets pre-conditioned, if the peak value of the leading symbol presses certain threshold value Better than the peak value of the common leading symbol, then it is judged as leading symbol, is otherwise judged as common leading symbol.
7. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that
The position for determining 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 in the presence of the leading symbol for expecting to receive, determining leading symbol in thing according to the big residing partial value of peak value or maximum Manage the position of appearance in frame or carry out fractional part of frequency offset estimation.
8. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that
Using all or part of time domain waveform of leading symbol and/or all or part of time domain waveform of the leading symbol by Fu In the frequency-region signal that obtains after leaf transformation, comprised the following steps with solving 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 t easet ofasubcarriers pair The time-domain signal answered carries out computing, to solve the signaling information in the leading symbol as entrained by signaling sequence subcarrier, wherein Signaling sequence t easet ofasubcarriers are based on the set of known signaling sequence and produce.
9. the method for reseptance of leading symbol as claimed in claim 1, it is characterised in that also comprise the following steps：
1) according to position of the leading symbol in physical frame is determined, interception includes the signal for fixing subcarrier；
2) it is the signal comprising fixed subcarrier is corresponding with frequency domain stator carrier wave sequence or frequency domain stator carrier wave sequence Time-domain signal carries out computing, to obtain integer frequency offset estimation or channel estimation.
10. the method for reseptance of leading symbol as claimed in claim 9, it is characterised in that
Integer frequency offset estimation is obtained to comprise the following steps：
The whole of the time domain waveform of the leading symbol received according to position of the leading symbol for detecting in physical frame, interception Or a part；
By the way of the frequency sweep by the upper different frequency deviations of part time domain waveform modulation after, obtain several time-domain signals；And
Known frequency domain fixed sequence program subcarrier carries out the corresponding time-domain signal of inverse fourier transform, by known signal and each time domain Signal enters line slip correlation, and maximum correlation peaks occurs in selection, then the frequency deviation value modulated to it is integer frequency offset estimation value,
Wherein, the frequency deviation region of confrontation required for swept frequency range correspondence system.
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