CN101035103A - Pilot code generation method and device of the orthogonal frequency division multiplexing access system - Google Patents
Pilot code generation method and device of the orthogonal frequency division multiplexing access system Download PDFInfo
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Abstract
The invention discloses a producing method of leading code about OFDMA system, whose launching end launch K kinds of signals of leading code. K is positive whole number. The methods include: A. Configuration of the same Segment leading code signal frequency-domain structure has been modulation for each of the two PN sequences subcarrier location at least a difference of MXK; each configuration of the two Segment leading code modulation signal has been the PN sequence subcarrier starting point location at least a difference of M, M is the power of two; B. Launched by the leading anti-code signal for Fast Fourier Transform IFFT, get all the leading Segment code signal and the Segment leading code superimposed on the signal in the time domain are at least a repeat of the M structure. The present invention also discloses a device, invented by this method and device code can be achieved in the time domain leading the duplication of structures.
Description
Technical field
The present invention relates to OFDM and insert (OFDMA, Orthogonal Frequency DivisionMultiplexing Access) systems technology, the pilot code generation method and the device of particularly a kind of OFDMA system.
Background technology
At present, with OFDM (OFDM, Orthogonal Frequency DivisionMultiplexing) for the multi-carrier transmission technology of representative owing to have good anti-frequency selective fading performance and higher advantages such as band efficiency, be subjected to application more and more widely in recent years.Not only be applied to digital video broadcasting (DAB, Digital Audio Broadcasting) system, digital video broadcast terrestrial (DVB-T, Terrain Digital Video Broadcasting) system and WLAN (wireless local area network) (WLAN, Wireless Local Area Network) in, more becomes the key technology of back three generations (B3G) mobile communication system.OFDMA is a kind of new access mode that is modulated to the basis with OFDM, is by provide the method for part available subcarrier to realize that the multi-user inserts for each user.
The OFDMA system adopts the single frequency network mode usually, and promptly the frequency duplex factor as one of all sub-districts is 1.In order to reduce the interference of minizone, the subcarrier in the same sub-district will be distributed to different sector (Segment), at the sub-district adjacent, and the Segment difference of two adjacent sub-districts, the cell id (ID_cell) of these two adjacent sub-districts is scarcely together simultaneously.Like this can be so that being in the subcarrier that Cell Edge User distributes can partially overlap, thus presence of intercell interference reduced.So when the mobile subscriber initially inserts, must obtain the ID_cell and the Segment of its sub-district, place correspondence, could obtain the information of its employed physical sub-carrier, to demodulate correct data message.
In the prior art, adopt 114 lead codes to distinguish different Segment and ID_cell.Lead code is positioned at the frame head of each downlink frame, accounts for an OFDM symbol.When the user initially inserts, at first synchronous with the downlink frame that the base station is sent, and need determine used Segment and ID_cell by the search lead code.The cell search process of OFDMA system so the search procedure of lead code is otherwise known as.In lead code (sub-district) search procedure, no matter adopting the time domain match search still is the frequency domain match search, all needs at first to determine the starting point that lead code occurs.Lead code is arranged in the position that a frame begins most, so the start position that correctly detects frame is very important for user's initial access process.
In the ofdm system that adopts lead code,, adopt the preamble structure that has repeat property on the time domain usually in order to introduce more redundant information.The repetitive structure of this lead code, can by on frequency domain clocklike zero insertion obtain.Fig. 1 is the schematic diagram that concerns between the frequency domain zero insertion of lead code and the time domain repetitive structure.Among Fig. 1, setting the subcarrier number contain data is N, the frequency-domain structure shown in the left side, and the right domain structure when being depicted as.Below from top to bottom successively to the frequency-domain structure of three kinds of lead codes shown in Figure 1 and the time domain structure described:
1, the lead code shown in the top
At frequency domain, insert 1 zero every 2 subcarriers, do the anti-fast Fourier transform of 2N point (IFFT) computing, this lead code presents the repeat property of two sections of front and back in time domain;
2, the lead code shown in the centre
At frequency domain, insert 2 zero every 2 subcarriers, do 3N point IFFT computing, this lead code presents three sections repeat property in time domain;
What need specified otherwise here is: owing to carry out counting of FFT/IFFT is 2 power, rather than 3 multiple, therefore in fact can't do 3N point IFFT computing, can't present three sections repetitive structures on the time domain, three segment datas that can't be repeated fully, thereby influence utilizes repeat property to carry out the estimated performance of mark frequency offset estimating, must rely on the smart estimation of follow-up mark frequency deviation and could satisfy system requirements, the complexity that this realizes the increase system.
Wherein, base station node B will bring in the preamble signal of launching self each Segment that has jurisdiction over as emission; When UE inserted, being treated to base station node B of primarily finishing was synchronous, comprising: frame synchronization, correcting frequency deviation, Cell searching (lead code search) etc.Wherein, regularly synchronous and frequency offset estimating is to finish the prerequisite of lead code search.
3, the lead code shown in the bottom, wherein K is any positive integer
According to the 1 and 2 described rules that concern between the time domain repetitive structure of lead code frequency-domain structure territory of obtaining: if at frequency domain, insert K-1 zero between per two subcarriers, do K*N point IFFT computing after, this preamble signal will present K section repeat property on time domain.To those skilled in the art, inserting K-1 zero result between described per two subcarriers is exactly: the position of per two subcarriers differs K.
In ofdm system, adopt this lead code usually in the frame head position with repetitive structure.Because the correlation that repetitive structure is introduced is so can utilize this correlation to finish functions such as Time and Frequency Synchronization function and carrier-in-interference noise ratio (CINR) estimation.
But, the regulation of pressing existing protocol, the lead code superposed signal of each Segment can't present repeat property in time domain.In the system of existing protocol regulation, the frequency-domain structure of lead code has been per two adjacent modulated exists two to be 0 subcarrier between the subcarrier of pseudorandom (PN) sequence.The preamble carrier (Preamble Carrier Set) that lead code under the different Segment is corresponding different, the difference of different preamble carrier are to modulate the start position difference of the subcarrier of leading PN sequence.The constructive method of described preamble carrier is as shown in Equation (1):
n＝Guard_left+segment_offset+3k (1)
Here, n is the position that preamble carrier is concentrated each subcarrier, and Guard_left is a left side protection number of sub carrier wave; Segment_offset=1,2,3, represent the sector biasing, its three kinds of values are corresponding segment0, segment1 and segment2 respectively; K=0,1,2 ... 283, respectively corresponding 87 o'clock to 1024 o'clock fast Fourier transform (FFT) the OFDM symbol.In ofdm system, whole frequency band is divided into a plurality of subcarriers, a frequency in the corresponding frequency band of each subcarrier, the position of so-called subcarrier just is meant the position of subcarrier frequency points corresponding, the frequency that the different frequent points position is corresponding different, the difference on the frequency between the different frequent points of the available different sub carrier correspondence of the difference of different sub carrier position quantizes.
Fig. 2 is the lead code frequency-domain structure schematic diagram under three different Segment in the prior art.Among Fig. 2, three different Segment are respectively: Segment0, Segment1 and Segment2.The preamble carrier of these three the different Segment correspondences all by formula method of (1) description constitutes, and in the OFDM of 1024 FFT character position, left side protection number of sub carrier wave is 86, and right protection number of sub carrier wave also is 86.
Wherein, the preamble carrier of Segment0 correspondence is concentrated, the start position of subcarrier is 87, end position is 936, this start position also is the subcarrier original position of the preamble signal of these three Segment, wherein the subcarrier of non-zero is represented with the filled arrows that makes progress, and is that zero subcarrier is represented with round dot; The preamble carrier of Segment1 correspondence is concentrated, and the start position of subcarrier is 88, and end position is 937, and wherein the subcarrier of non-zero is represented with the vertical line of upper end band closed square, is that zero subcarrier is represented with round dot; The preamble carrier of Segment2 correspondence is concentrated, and the start position of subcarrier is 89, and end position is 938, and wherein the subcarrier of non-zero is represented with the vertical line of upper end band empty circles, is that zero subcarrier is represented with round dot; Concentrate in the preamble carrier of this three Segment, per two adjacent modulation all exist between the subcarrier of known PN sequence two to be zero subcarrier, promptly per two adjacent modulation all insert two zero between the subcarrier of known PN sequence.
As seen, the frequency-domain structure of lead code shown in Figure 2 is: the preamble carrier that the lead code under the different Segment is corresponding different, the difference of different preamble carrier is to modulate the starting point difference of the subcarrier of leading PN sequence, as: among Fig. 2, the subcarrier start position of the preamble carrier modulation PN sequence of Segment0 and Segment1 correspondence differs 1 sub-carrier positions, and the subcarrier start position of the preamble carrier modulation PN sequence of Segment1 and Segment2 correspondence differs 1 sub-carrier positions; And, concentrate in the preamble carrier of same Segment, per two modulated all exist between the subcarrier of PN sequence two to be 0 subcarrier.
When the mobile subscriber inserts the sub-district, can receive the preamble signal that belongs to different Segment from a plurality of sub-districts.Belong to respectively Segment0, Segment1, Segment2 three preamble signal frequency-domain structure as shown in Figure 3.In the OFDM of 1024 FFT character position, left side protection number of sub carrier wave is 86, and right protection number of sub carrier wave also is 86.
Wherein, the subcarrier original position of this superposed signal is 87, and end position is 938, and does not have the characteristic of zero insertion between each subcarrier.Like this, the class repeat property on the time domain no longer keeps, and the method that causes utilizing the repeat property correlation to carry out timing coarse synchronization lost efficacy, thereby can't form tangible correlation peak, omission occurred.In this case, the mobile subscriber who is in three sub-district intersections can't search corresponding Segment and ID_Cell information, and the user just can't insert.
In sum, in the existing OFDMA system, the implementation of lead code is perfect not enough, lead code can't present the characteristic that repeats fully of time domain in some system, at the sub-district intersection, the lead code that forms after the signal stack from a plurality of sub-districts can't present repeat property on time domain, even sort out and classify does not possess like repeat property.Like this, under many cell conditions, will cause the loss height of thick timing, cause the Cell searching failure, also can't implement some based on the reliable of the complete repeat property of lead code and simple algorithm, such as: be difficult to guarantee the mark frequency offset estimation accuracy and estimate based on the CINR of complete repetitive structure etc.These all will improve the implementation complexity of OFDMA system.
Summary of the invention
In view of this, main purpose of the present invention is to provide the pilot code generation method and the device of a kind of OFDMA system, can realize the repetitive structure characteristic of lead code on time domain, significantly reduces the thick timing false dismissal probability under many cell conditions, improves systematic function.
For achieving the above object, technical scheme of the present invention is achieved in that
The invention discloses the pilot code generation method that a kind of OFDM inserts the OFDMA system, the preamble signal of transmitting terminal emission K kind sector Segment, K is a positive integer; This method comprises:
The sub-carrier positions of pseudorandom PN sequence that the frequency-domain structure that A. disposes the preamble signal of same Segment is per two modulated differs M * K at least; Dispose modulated in the preamble signal of per two Segment the start position of subcarrier of PN sequence differ M at least, M is 2 power;
B. each preamble signal of being launched is made anti-fast Fourier transform IFFT, obtain possessing at least on the time domain preamble signal of each Segment of M section repetitive structure and the superposed signal of each Segment preamble signal.
Wherein, per two modulated of the described configuration of steps A the sub-carrier positions of PN sequence differ at least among M * K, the described M * K that differs at least is: differ M * K * j; Wherein, j is the positive integer greater than 1.
Wherein, in the preamble signal of per two Segment of the described configuration of steps A modulated the start position of subcarrier of the PN sequence method that differs M at least be:
Dispose modulated in the preamble signal of per two adjacent Segment the start position of subcarrier of PN sequence all differ M * i; Wherein, i is that positive integer and i equal j for a short time.
Wherein, in the preamble signal of per two Segment of the described configuration of steps A modulated the start position of subcarrier of the PN sequence method that differs M at least be:
1) determines that location sets is: Y=[Y
0, Y
0+ M ..., Y
0+ M * x ..., Y
0+ M * (K * j-1)]; Wherein, Y is a location sets, Y
0Be the subcarrier original position, x is continuous integral number and x=0,1 ..., K * j-1;
2) from determined location sets optional K position respectively as modulated in the preamble signal of K kind Segment the start position of subcarrier of PN sequence.
Wherein, described transmitting terminal is base station node B.
The invention also discloses the lead code generating apparatus of a kind of OFDMA system, this device is used to generate the preamble signal of K kind Segment, and K is a positive integer; This device comprises:
Frequency domain lead code constructing module is used to receive the sub-carrier positions indication and from the lead code PN sequence of outside, generate modulated the PN sequence the frequency domain preamble signal and export the IFFT computing module to;
The IFFT computing module is used to receive from the frequency domain preamble signal of described frequency domain lead code constructing module and carries out the IFFT calculation process, obtains time domain preamble signal and the output of each Segment;
Wherein, this device further comprises:
Subcarrier parameter processing module is used for receiving K and repeat property parameter M from the outside, obtains zero insertion indication and start position indication and exports to the sub-carrier positions generation module according to K that receives and M; Wherein, M is 2 power;
The sub-carrier positions generation module is used to receive from the zero insertion indication and the start position of subcarrier parameter processing module and indicates, and determines the position of each subcarrier in the preamble signal and exports sub-carrier positions and indicate to described frequency domain lead code constructing module; The indication of described sub-carrier positions is used for indication: the sub-carrier positions of PN sequence that the frequency-domain structure of the preamble signal of same Segment is per two modulated differs M * K at least, in the preamble signal of per two Segment modulated the start position of subcarrier of PN sequence differ M at least;
The time domain preamble signal of each Segment that described IFFT computing module obtains possesses M section repetitive structure at least, and the superposed signal of the time domain preamble signal of each Segment also possesses M section repetitive structure at least.
Wherein, described subcarrier parameter processing module comprises:
Subcarrier zero insertion number generation module, be used for from outside reception M and K, generate the zero insertion indication and export described sub-carrier positions generation module to, the indication of described zero insertion be used for indicating same Segment per two modulated of preamble signal insert M * K-1 zero between the subcarrier of PN sequence at least, make described per two modulated the sub-carrier positions of PN sequence differ M * K at least;
The subcarrier start position is chosen module, be used for from outside reception M, determine the start position of the subcarrier in the preamble signal of each Segment, and the output start position indicates to described sub-carrier positions generation module, and the indication of described start position is used to indicate the start position of the preamble signal sub-carriers of per two Segment to differ M at least.
Wherein, this device is arranged at the transmitting terminal of preamble signal.
Wherein, described transmitting terminal is base station node B.
By such scheme as can be seen, key of the present invention is: transmitting terminal is when the preamble signal of emission K kind Segment, and the sub-carrier positions of PN sequence that the frequency-domain structure that disposes the preamble signal of same Segment is per two modulated differs M * K at least; Dispose modulated in the preamble signal of per two Segment the start position of subcarrier of PN sequence differ M at least, M is 2 power.
Therefore, the pilot code generation method and the device of OFDMA provided by the present invention system, can not only make the preamble signal of single subdistrict possess at least two sections repeat property, can also make the lead code superposed signal of a plurality of sub-districts (being Segment) possess at least two sections repeat property equally, be beneficial under many cell conditions, accurately finish lead code (sub-district) search, overcome the high defective of thick timing false dismissal probability that prior art exists, the estimated accuracy of goals for frequency deviation is improved, significant for user's initial access
Description of drawings
Fig. 1 is the schematic diagram that concerns between the frequency domain zero insertion of lead code and the time domain repetitive structure;
Fig. 2 is the lead code frequency-domain structure schematic diagram under three different Segment in the prior art;
Fig. 3 is the frequency-domain structure schematic diagram of superposed signal of the lead code of different Segment;
Fig. 4 is the inventive method one preferred embodiment handling process schematic diagram;
Fig. 5 is the lead code frequency-domain structure schematic diagram under three different Segment that adopt the inventive method;
Fig. 6 is the frequency-domain structure schematic diagram of superposed signal of the lead code of three different Segment shown in Figure 5;
Fig. 7 is that structural representation is formed in apparatus of the present invention one preferred embodiment.
Embodiment
The invention provides the pilot code generation method of a kind of OFDMA system, its main design philosophy is: the total K kind Segment of supposition, the structure of preamble signal on frequency domain of the K kind Segment of transmitting terminal emission is: the preamble carrier at same Segment is concentrated, per two modulated have M * K-1 null value at least between the subcarrier of PN sequence, M is 2 power.Simultaneously can make the frequency-domain structure of the superposed signal of each Segment lead code be: per two modulated the sub-carrier positions of PN sequence differ M at least.Like this, the lead code that sends of the transmitting terminal time-domain signal of doing to obtain after the IFFT computing repetitive structure that has the M section at least; The lead code superposed signal that receiving terminal receives has the repetitive structure of M section at least on time domain, and the lead code of each Segment that receives also has the repetitive structure of M section at least on time domain.Because M is 2 power, therefore resulting single preamble signal and a plurality of lead code superposed signal all possess two sections complete repeat property at least.
Usually, UE will be as the signal receiving end of lead code, and base station node B will be as the signal transmitting terminal of lead code, base station node B need transmit by the described lead code frequency-domain structure of the inventive method, thereby UE can obtain having on the time domain preamble signal of repeat property, and can receive the superposed signal of the preamble signal of different Segment at the intersection of different districts as UE, this superposed signal still has repeat property, thereby can determine the initial position of frame and accurately search lead code, to realize successfully access.
Fig. 4 is the inventive method one preferred embodiment handling process schematic diagram.In the present embodiment, be set with K kind Segment, and will make the superposed signal of lead code present M section repetitive structure in time domain, M also can be called as the repeat property parameter, need be pre-configured in the signal transmitting terminal of lead code.As shown in Figure 4, the concrete processing comprises:
Step 401: transmitting terminal is when the preamble signal of each Segment of emission, and in frequency domain, the subcarrier start position difference of the preamble carrier of different Segment and per two adjacent subcarrier start positions differ M; The preamble carrier of same Segment is concentrated, per two adjacent modulated of being launched have M * K-1 zero between the subcarrier of PN sequence.
Step 402: simultaneously, transmitting terminal is in emission during preamble signal, to the frequency-region signal of lead code do the IFFT computing obtain possessing M section at least, at most the repeat property of M * K section time-domain signal and be transmitted to receiving terminal.Here, if K also is 2 power, then can obtain possessing M * time-domain signal of K section repetitive structure; Otherwise obtain possessing the time-domain signal of M section repetitive structure.
Step 403: the lead code time-domain signal that receiving terminal receives various Segment correspondences gets access to the superposed signal of various lead codes, the frequency-domain structure of this superposed signal is: per two adjacent modulated the sub-carrier positions of PN sequence differ M, therefore on time domain, possess M section repeat property.In addition, because the lead code time-domain signal of each Segment all possesses at least M section, the repeat property of M * K section at most, therefore, receiving terminal is when receiving the preamble signal of single subdistrict, and what obtain is exactly M section, the time-domain signal that repeats of M * K section at most at least.
Here, in frequency domain, exist M-1 to be zero position between concentrated per two the adjacent subcarriers of the preamble carrier of this superposed signal correspondence, this kind superposed signal is made the time-domain signal that the IFFT computing will obtain possessing M section repetitive structure.
For ease of understanding method shown in Figure 4, be example with M=2, K=3 below, in conjunction with Fig. 5 and Fig. 6 the processing of the inventive method is further described.
Fig. 5 is the lead code frequency-domain structure schematic diagram under three different Segment that adopt the inventive method.Among Fig. 5, three different Segment are respectively: segment0, segment1 and segment2.These three the corresponding different preamble carrier of different Segment; these Segment belong to the system that the protection subcarrier is arranged; therefore; be distributed with left side protection subcarrier and right protection subcarrier about preamble carrier respectively; whether but exist left side protection subcarrier or right protection subcarrier to the technical solution of the present invention did not influence, the present invention can be applicable to the system of unprotect subcarrier equally.Here, GL is a left side protection number of sub carrier wave; Sg0, Sg1 and Sg2 are respectively the sector biasing of Segment0, Segment1 and Segment2, and value is respectively 1,2,3; Pk is the number of sub carrier wave that preamble carrier is concentrated.
Wherein, the preamble carrier of Segment0 correspondence is concentrated, and the start position of subcarrier is GL+Sg0+6 * 0, and end position is that GL+Sg0+6 * (Pk-1), wherein the subcarrier of non-zero is represented with the filled arrows that makes progress, and is that zero subcarrier is represented with round dot; The preamble carrier of Segment1 correspondence is concentrated, and the start position of subcarrier is GL+Sg1+6 * 0, and end position is that GL+Sg1+6 * (Pk-1), wherein the subcarrier of non-zero is represented with the vertical line of upper end band closed square, is that zero subcarrier is represented with round dot; The preamble carrier of Segment2 correspondence is concentrated, and the start position of subcarrier is GL+Sg2+6 * 0, and end position is that GL+Sg2+6 * (Pk-1), wherein the subcarrier of non-zero is represented with the vertical line of upper end band empty circles, is that zero subcarrier is represented with round dot.Concentrate in the preamble carrier of this three Segment, per two adjacent modulated all exist between the subcarrier of PN sequence M * K-1 to be zero subcarrier, promptly 5 zero; The start position of the subcarrier of per two adjacent Segment lead codes differs M, and promptly 2, such as: the subcarrier start position of Segment0 and Segment1 lead code differs 2, and the subcarrier start position of the lead code of Segment1 and Segment2 differs 2.
Fig. 6 is the frequency-domain structure schematic diagram of superposed signal of the lead code of three different Segment shown in Figure 5.Wherein, the preamble carrier of this superposed signal correspondence is concentrated, and the start position of subcarrier is GL+Sg0+6 * 0, and end position is GL+Sg2+6 * (Pk-1), and exists 1 to be zero position between per two adjacent subcarriers.Like this, just can present two sections repetitive structure on the time domain.
In the described example of above-mentioned Fig. 4 to Fig. 6, the preamble carrier of same Segment is concentrated, per two adjacent modulated of being launched the sub-carrier positions of PN sequence differ M * K; And, the modulated of the preamble carrier of different Segment the subcarrier start position of PN sequence differ M.In actual applications, also can dispose sub-carrier positions by following several method: 1, the preamble carrier of same Segment is concentrated, per two adjacent modulated the sub-carrier positions of PN sequence differ M * K * j, j is a positive integer; 2, on 1 basis, the subcarrier start position that disposes the preamble carrier of different Segment differs M * i, and i is positive integer and equals j for a short time; 3, on 1 basis, at first, determine location sets Y=[Y
0, Y
0+ M ..., Y
0+ M * x ..., Y
0+ M * (K * j-1)], wherein, Y is a location sets, Y
0Be the subcarrier original position, the value of x is continuous integral number and x=0,1 ..., K * j-1; Then, in the position of the K * j from determined location sets optional K position respectively as modulated in the preamble signal of K kind Segment the start position of subcarrier of PN sequence.The time-domain signal that the preamble signal that disposes by these three kinds of modes does to obtain after the IFFT computing all has at least M section, the repetitive structure of M * K * j section at most; The lead code superposed signal that receiving terminal receives has the repetitive structure of M section at least on time domain, and the lead code of each Segment that receives also has the repetitive structure of M section at least on time domain.
Based on above-mentioned configuration mode, there is a kind of special preferable example of realization effect.Because, as long as having two sections complete repeat property, the preamble signal of stack just can utilize time-frequency synchronization method based on two sections repetitions, so this example will realize that independent lead code and each lead code superposed signal possess two sections repetitive structures completely, just default M=2.This embodiment comprises the steps:
Step 401 ': transmitting terminal is when the preamble signal of each Segment of emission, in frequency domain, the preamble carrier of same Segment is concentrated, per two adjacent modulated of being launched insert M * K * j-1 zero between the subcarrier of PN sequence, promptly 2 * K * j-1 individual zero, wherein j is a positive integer, and K is the number of Segment; The subcarrier start position difference of the preamble carrier of different Segment and the subcarrier start position of per two adjacent preamble carrier differ 2 multiple.
Here, the minimum position number that on behalf of the subcarrier start position of different preamble carrier, M differ, M=2 in the present embodiment, Y
0=0.When j=1, the preamble carrier of K different Segment is concentrated, the minimum value that the subcarrier start position of adjacent two preamble carrier differs is 2, and the total K kind of the subcarrier start position of the preamble carrier of each Segment then is respectively: 0,2,4 ..., 2K-2; When j＞1, the minimum value that the subcarrier start position of the preamble carrier of K different Segment differs is 2, then the desirable position of the subcarrier start position of the preamble carrier of each Segment has K * j kind, be respectively: 0,2,4 ..., 2 (K * j-1) only needs take up an official post in this K * j kind position and gets K position and get final product.For this example, independent lead code requires to present two sections complete repeat property and get final product, thus need only the multiple that M * K * j is 2 power, and M is exactly 2 power, is not decided to be 2 power so require K * j one.
Step 402 ': simultaneously, transmitting terminal when sending preamble signal, to the frequency-region signal of lead code do that the IFFT computing obtains possessing at least two sections, the time-domain signal of maximum 2 * K * j section repeat property and be transmitted to receiving terminal.
Step 403 ': the lead code time-domain signal that receiving terminal receives various Segment correspondences gets access to the superposed signal of various lead codes, this superposed signal is the time-domain signal that possesses at least two sections repeat property, and the preamble signal of each single sub-district also possesses two sections repeat property at least.。
Here, in frequency domain, there is at least 1 zero between per two adjacent subcarriers of the preamble carrier of this superposed signal correspondence, this kind superposed signal done the IFFT computing will obtain two sections complete repetitive structures on time domain.
Based on the invention described above method, the present invention also provides the lead code generating apparatus of a kind of OFDMA system.In existing lead code generating apparatus, comprise: be used to generate the frequency domain lead code constructing module of frequency domain lead code and be used for the frequency domain lead code is carried out the IFFT computing module of IFFT computing with output time domain lead code.Apparatus of the present invention also further comprise except comprising existing frequency domain lead code constructing module and IFFT computing module: subcarrier parameter processing module and sub-carrier positions generation module.
Wherein, subcarrier parameter processing module is used for receiving the subcarrier parameter from the outside, comprises described M of previous methods and K, obtains zero insertion indication and start position indication and exports to the sub-carrier positions generation module according to the subcarrier parameter that receives; Zero insertion indication that sub-carrier positions generation module basis receives and start position are indicated the position of each subcarrier in the preamble signal of determining K kind Segment and are exported sub-carrier positions and indicate to frequency domain lead code constructing module; Frequency domain lead code constructing module receives from the sub-carrier positions indication of sub-carrier positions generation module with from the lead code PN sequence of outside, generate modulated the PN sequence the frequency domain preamble signal and export the IFFT computing module to; This IFFT computing module then is used for the frequency domain preamble signal that receives is carried out the IFFT calculation process, obtain time domain preamble signal and the output of each Segment, wherein the time domain preamble signal of each Segment will possess M section repetitive structure at least, and the superposed signal of the preamble signal of each Segment also possesses M section repetitive structure at least.Here, M is required repeat property parameter, is used to indicate the repeat property that will obtain; K is the number of current Segment.The indication of described sub-carrier positions is used for indication: the sub-carrier positions of pseudorandom PN sequence that the frequency-domain structure of the preamble signal of same Segment is per two modulated differs M * K at least, in the preamble signal of per two Segment modulated the start position of subcarrier of PN sequence differ M at least;
Described subcarrier parameter processing module can be made of two parts, comprising: subcarrier zero insertion number generation module and subcarrier start position are chosen module.Wherein, described subcarrier zero insertion number generation module is used to receive repeat property parameter (being M) and Segment number (being K), generate the zero insertion indication and export the sub-carrier positions generation module to, this zero insertion indication will be indicated the preamble carrier of same Segment to concentrate and be inserted M * K-1 individual zero between per two subcarriers at least; Described subcarrier start position is chosen module and is used to receive repeat property parameter (being M), determine the start position of the preamble carrier sub-carriers of each Segment, and export start position and indicate to the sub-carrier positions generation module, this start position indication should indicate the start position of the preamble carrier sub-carriers of per two Segment to differ M at least.Wherein, subcarrier zero insertion number generation module and subcarrier start position are chosen inside modules and are determined the zero insertion number, determine that the handling principle of start position follows the described principle of previous methods, no longer describe in detail here.
Apparatus of the present invention are set at the signal transmitting terminal of lead code usually, such as base station node B, adopt this device back signal transmitting terminal can launch the preamble signal that possesses M section repetitive structure on the time domain.Here, M is 2 power and equals 2 greatly.
In sum, behind application the inventive method and the device,, still under the environment of single sub-district, all can make lead code on time domain, keep the two sections structures that repeat fully in front and back no matter at many sub-districts intersection.Avoided under many cell scenario the thick regularly high defective of false dismissal probability.Simultaneously, this method can make the estimated accuracy of goals for frequency deviation be improved.In addition, compare with prior art one, use the present invention after transmitting terminal when the emission lead code, the reduction of counting of required PN sequence, thus can further reduce the computation complexity of Cell searching.
The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.All any modifications of being done within the spirit and principles in the present invention, be equal to replacement, improvement etc., all be included in protection scope of the present invention.
Claims (9)
1, a kind of OFDM inserts the pilot code generation method of OFDMA system, the preamble signal of transmitting terminal emission K kind sector Segment, and K is a positive integer; It is characterized in that this method comprises:
The sub-carrier positions of pseudorandom PN sequence that the frequency-domain structure that A. disposes the preamble signal of same Segment is per two modulated differs M * K at least; Dispose modulated in the preamble signal of per two Segment the start position of subcarrier of PN sequence differ M at least, M is 2 power;
B. each preamble signal of being launched is made anti-fast Fourier transform IFFT, obtain possessing at least on the time domain preamble signal of each Segment of M section repetitive structure and the superposed signal of each Segment preamble signal.
2, method according to claim 1 is characterized in that, per two modulated of the described configuration of steps A the sub-carrier positions of PN sequence differ at least among M * K, the described M * K that differs at least is:
Differ M * K * j; Wherein, j is the positive integer greater than 1.
3, method according to claim 2 is characterized in that, in the preamble signal of per two Segment of the described configuration of steps A modulated the start position of subcarrier of the PN sequence method that differs M at least be:
Dispose modulated in the preamble signal of per two adjacent Segment the start position of subcarrier of PN sequence all differ M * i; Wherein, i is that positive integer and i equal j for a short time.
4, method according to claim 2 is characterized in that, in the preamble signal of per two Segment of the described configuration of steps A modulated the start position of subcarrier of the PN sequence method that differs M at least be:
1) determines that location sets is: Y=[Y
0, Y
0+ M ..., Y
0+ M * x ..., Y
0+ M * (K * j-1)]; Wherein, Y is a location sets, Y
0Be the subcarrier original position, x is continuous integral number and x=0,1 ..., K * j-1;
2) from determined location sets optional K position respectively as modulated in the preamble signal of K kind Segment the start position of subcarrier of PN sequence.
5, according to each described method of claim 1 to 4 be, it is characterized in that described transmitting terminal is base station node B.
6, the lead code generating apparatus of a kind of OFDMA system, this device is used to generate the preamble signal of K kind Segment, and K is a positive integer; This device comprises:
Frequency domain lead code constructing module is used to receive the sub-carrier positions indication and from the lead code PN sequence of outside, generate modulated the PN sequence the frequency domain preamble signal and export the IFFT computing module to;
The IFFT computing module is used to receive from the frequency domain preamble signal of described frequency domain lead code constructing module and carries out the IFFT calculation process, obtains time domain preamble signal and the output of each Segment;
It is characterized in that this device further comprises:
Subcarrier parameter processing module is used for receiving K and repeat property parameter M from the outside, obtains zero insertion indication and start position indication and exports to the sub-carrier positions generation module according to K that receives and M; Wherein, M is 2 power;
The sub-carrier positions generation module is used to receive from the zero insertion indication and the start position of subcarrier parameter processing module and indicates, and determines the position of each subcarrier in the preamble signal and exports sub-carrier positions and indicate to described frequency domain lead code constructing module; The indication of described sub-carrier positions is used for indication: the sub-carrier positions of PN sequence that the frequency-domain structure of the preamble signal of same Segment is per two modulated differs M * K at least, in the preamble signal of per two Segment modulated the start position of subcarrier of PN sequence differ M at least;
The time domain preamble signal of each Segment that described IFFT computing module obtains possesses M section repetitive structure at least, and the superposed signal of the time domain preamble signal of each Segment also possesses M section repetitive structure at least.
7, device according to claim 6 is characterized in that, described subcarrier parameter processing module comprises:
Subcarrier zero insertion number generation module, be used for from outside reception M and K, generate the zero insertion indication and export described sub-carrier positions generation module to, the indication of described zero insertion be used for indicating same Segment per two modulated of preamble signal insert M * K-1 zero between the subcarrier of PN sequence at least, make described per two modulated the sub-carrier positions of PN sequence differ M * K at least;
The subcarrier start position is chosen module, be used for from outside reception M, determine the start position of the subcarrier in the preamble signal of each Segment, and the output start position indicates to described sub-carrier positions generation module, and the indication of described start position is used to indicate the start position of the preamble signal sub-carriers of per two Segment to differ M at least.
8, according to claim 6 or 7 described devices, it is characterized in that this device is arranged at the transmitting terminal of preamble signal.
9, device according to claim 8 is characterized in that, described transmitting terminal is a base station node B.
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| WO2010115304A1 (en) * | 2009-04-09 | 2010-10-14 | 华为技术有限公司 | A method for random accessing, evolution-node b and terminal equipment |
| CN101188454B (en) * | 2007-12-21 | 2012-06-06 | 中兴通讯股份有限公司 | Enhancing method for system pilot code and initial access processing method of 802.16m system terminal |
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| WO2015196629A1 (en) * | 2014-06-27 | 2015-12-30 | 中兴通讯股份有限公司 | Method and device for estimating frequency offset of carriers |
| CN107113141B (en) * | 2015-01-21 | 2020-08-07 | 英特尔Ip公司 | Method, apparatus and medium for transmitting efficient packet format using preamble |
| CN107113141A (en) * | 2015-01-21 | 2017-08-29 | 英特尔Ip公司 | Method, device and the computer-readable medium of efficient packet format are sent with signal using the conventional part of lead code in a wireless local area network |
| CN111277535A (en) * | 2020-03-16 | 2020-06-12 | 成都希德电子信息技术有限公司 | Frequency-division time-division high-precision OFDM synchronization method and system |
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