CN101478520B - Descramble method and apparatus - Google Patents
Descramble method and apparatus Download PDFInfo
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- CN101478520B CN101478520B CN2008102397015A CN200810239701A CN101478520B CN 101478520 B CN101478520 B CN 101478520B CN 2008102397015 A CN2008102397015 A CN 2008102397015A CN 200810239701 A CN200810239701 A CN 200810239701A CN 101478520 B CN101478520 B CN 101478520B
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Abstract
The invention discloses a descrambling method and a device comprising: receiving a scrambling Orthogonal Frequency Division Multiplexing (OFDM) signals, respectively extracting the same numbers of more than one pilot in the adjacent OFDM signals; descrambling each pilot according to the known probably adopted N types of initial phases when scrambling, and obtaining N types of descrambling results for each pilot, wherein N is a positive integer; obtaining eight relative results for each pair of OFDM signals after performing relative operations to each pair of OFDM signals based on the descrambling results of each pilot; calculating and obtaining final needed eight energy values based on the eight relative results of each pair of the OFDM signals, determining the maximum value corresponding initial phase as an initial phase used when scrambling and using the initial phase to descramble. The application of the method and the device in the invention enables a receiving end to correctly recognize the initial phase used by a transmitting end, and further realize the descrambling.
Description
Technical field
The present invention relates to China Mobile's DMB (CMMB, China Mobile MultimediaBroadcasting) technology, de-scrambling method and device in the particularly a kind of CMMB system.
Background technology
The CMMB system is a kind of mobile digital multimedia broadcast system based on OFDM (OFDM, Orthogonal FrequencyDivision Multiplexing) technology.The OFDM technology is widely used in the broadcast system of data broadband, it is advantageous that transmission rate is bigger, and can resist stronger frequency selective fading.
In the CMMB system, adopt frame structure based on time slot (Time Slot), comprise 40 time slots (being numbered 0～39) in the per second, the length of each time slot is 25 milliseconds; Each time slot is made up of 1 beacon and 53 OFDM symbols (being numbered 0～52); In addition, each OFDM symbol is formed by several effective subcarriers, specifically, can comprise data subcarrier, scattered pilot and continuous pilot; Wherein, scattered pilot does not carry any information usually, is mainly used to the auxiliary reception end and carries out channel estimating and coherent detection and demodulation; Continuous pilot can be used for bearing system transmission indication information.
In order to improve emission effciency, promptly reduce peak value and average power ratio, existing CMMB system adds a multiple pseudo random sequence P at transmitting terminal in effective subcarrier of all OFDM symbols
c(n * N
V+ i) as scrambler; Concrete adding mode is for passing through complex symbol and P on each effective subcarrier
c(n * N
V+ i) carry out complex multiplication to realize:
Y
n(n×N
V+i)＝X
n(n×N
V+i)×P
c(n×N
V+i)，0≤i≤N
V-1，0≤n≤52 (1)
Wherein, X
n(n * N
V+ i) expression adds the individual effectively complex symbol of subcarrier of i on interior n the OFDM symbol of preceding each time slot of scrambler; Y
n(n * N
V+ i) expression adds behind the scrambler in each time slot i effective subcarrier on n the OFDM symbol; Nv represents the effective number of sub carrier wave in interior n the OFDM symbol of each time slot; In addition, based on before introduction as can be known, comprise 53 OFDM symbols in each time slot, its numbering is respectively 0～52, so the value of the n in the formula (1) is 0≤n≤52.
In addition, P
c(n * N
V+ i) concrete account form is:
Wherein, S
iAnd S
qBe binary pseudo-random sequence, produce that corresponding generator polynomial is: x by linear feedback shift register shown in Figure 1
12+ x
11+ x
8+ x
6+ 1.The initial value of described linear feedback shift register has 8 kinds, and is as shown in table 1:
| Option | |
| 0 | 0000?0000?0001 |
| 1 | 0000?1001?0011 |
| 2 | 0000?0100?1100 |
| 3 | 0010?1011?0011 |
| 4 | 0111?0100?0100 |
| 5 | 0000?0100?1100 |
| 6 | 0001?0110?1101 |
| 7 | 0010?1011?0011 |
The initial value of table 1 linear feedback shift register
In actual applications, specifically use which value can specify in advance as the initial value of linear feedback shift register; And in the scrambling process, the initial value of linear feedback shift register will be reset in the beginning of each time slot.
Like this, for receiving terminal, will there be a problem, because what the initial phase that receiving terminal adopts when may not know the transmitting terminal scrambling is, promptly adopt which value shown in the table 1 as the initial value of linear feedback shift register, so, just may cause problems such as descrambling mistake, thereby make CMMB system cisco unity malfunction.
Summary of the invention
In view of this, main purpose of the present invention is to provide a kind of de-scrambling method, the initial phase that makes receiving terminal in the CMMB system correctly to identify transmitting terminal to be adopted, and then correctly realize descrambling.
Another object of the present invention is to provide a kind of descrambler, the initial phase that makes receiving terminal in the CMMB system correctly to identify transmitting terminal to be adopted, and then correctly realize descrambling.
For achieving the above object, technical scheme of the present invention is achieved in that
A kind of de-scrambling method comprises:
Receive the orthogonal frequency division multiplex OFDM symbol after the scrambling, from least one pair of adjacent OFDM symbol wherein, extract an above pilot tone of similar number respectively;
The N kind initial phase that may adopt during according to known scrambling carries out descrambling to each pilot tone, obtains the N kind descrambling result at each pilot tone; Described N is a positive integer;
According to described N kind descrambling result at each pilot tone, every pair of OFDM symbol is carried out related operation, obtain N correlated results at every pair of OFDM symbol; And according to described N correlated results, calculate final N required energy value, the initial phase that is adopted when wherein maximum value corresponding initial phase is defined as scrambling at every pair of OFDM symbol;
The initial phase that utilization is determined carries out descrambling to the OFDM symbol that receives.
Wherein, described pilot tone is scattered pilot or continuous pilot, if be scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 2 that numbering differs, if be continuous pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 1 that numbering differs.
Preferably, the described N kind initial phase that may adopt during according to known scrambling carries out descrambling to each pilot tone, obtains comprising at the N kind descrambling result of each pilot tone:
The N kind initial phase that may adopt during according to known scrambling calculates the N kind scrambler of each pilot tone correspondence respectively;
Utilize the N kind scrambler of each pilot tone correspondence, each pilot tone is carried out descrambling, obtain N kind descrambling result at each pilot tone.
Describedly each pilot tone carried out descrambling comprise:
The N kind scrambler of each pilot tone correspondence is got conjugate operation respectively;
The N kind scrambler of getting behind the conjugate operation that each pilot tone is corresponding with it respectively multiplies each other.
Describedly every pair of OFDM symbol is carried out related operation, obtains comprising at N correlated results of every pair of OFDM symbol according to described N kind descrambling result at each pilot tone:
The N kind descrambling result of each pilot tone in one of them OFDM symbol is got conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, and will carry out addition corresponding to each multiplied result of identical initial phase.
Described according to described N correlated results at every pair of OFDM symbol, calculate final N required energy value and comprise:
Calculate the energy value of the every pair of pairing N of OFDM symbol correlated results respectively, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtain final N required energy value.
The energy value of every couple of pairing N of OFDM symbol of described calculating correlated results comprises:
Calculate the absolute value of a described N correlated results respectively; Perhaps, calculate respectively a described N correlated results square.
Preferably, the value of described N is 8.
A kind of descrambler comprises:
Extracting unit is used to receive the orthogonal frequency division multiplex OFDM symbol after the scrambling, extracts an above pilot tone of similar number from least one pair of adjacent OFDM symbol wherein respectively;
The first descrambling unit, the N kind initial phase that may adopt when being used for according to known scrambling carries out descrambling to each pilot tone, obtains the N kind descrambling result at each pilot tone; Described N is a positive integer;
Computing unit is used for according to described N kind descrambling result at each pilot tone every pair of OFDM symbol being carried out related operation, obtains N correlated results at every pair of OFDM symbol; And, calculate final N required energy value according to described N correlated results at every pair of OFDM symbol;
Determining unit is used for the initial phase that is adopted when maximum value corresponding initial phase with described final required N energy value is defined as scrambling;
The second descrambling unit is used to utilize the described initial phase of determining that the OFDM symbol that receives is carried out descrambling.
Wherein, described pilot tone is scattered pilot or continuous pilot, if be scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 2 that numbering differs, if be continuous pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 1 that numbering differs.
Preferably, the described first descrambling unit comprises:
First computation subunit, the N kind initial phase that may adopt when being used for according to known scrambling calculates the N kind scrambler of each pilot tone correspondence respectively;
Second computation subunit is used for the N kind scrambler of each pilot tone correspondence is got conjugate operation respectively, and the N kind scrambler of getting behind the conjugate operation that each pilot tone is corresponding with it respectively multiplies each other, and obtains the N kind descrambling result at each pilot tone.
Described computing unit comprises:
The 3rd computation subunit, be used at every pair of OFDM symbol, N kind descrambling result with each pilot tone in one of them OFDM symbol gets conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, to carry out addition corresponding to each multiplied result of identical initial phase, obtain N correlated results at every pair of OFDM symbol;
The 4th computation subunit is used to calculate the energy value of the every pair of pairing N of OFDM symbol correlated results, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtains final N required energy value.
Preferably, the value of described N is 8.
As seen, adopt technical scheme of the present invention, under the situation of the initial phase that is adopted when not knowing the transmitting terminal scrambling, at first extract an above pilot tone of similar number respectively from least one pair of adjacent OFDM symbol that receives, this pilot tone is scattered pilot or continuous pilot; Then, the N kind initial phase that may use during according to known transmitting terminal scrambling calculates the N kind scrambler of each pilot tone correspondence respectively, and utilizes this N kind scrambler, and each pilot tone is carried out descrambling, obtains the N kind descrambling result at each pilot tone; Afterwards, at every pair of OFDM symbol, respectively the N kind descrambling result of an above pilot tone in one of them OFDM symbol and the N kind descrambling result of an above pilot tone in another OFDM symbol are carried out related operation, and according to the result of calculation of every pair of OFDM symbol correspondence, determine final N required energy value, after considering that the scrambler that utilizes correct initial phase to generate carries out descrambling, corresponding energy value is with maximum, so, the initial phase that is adopted when the maximum value corresponding initial phase in described final required N the energy value is defined as the transmitting terminal scrambling, and utilize this initial phase of determining that the OFDM symbol that receives is carried out descrambling.Compared with prior art, the initial phase that scheme of the present invention makes receiving terminal correctly to identify transmitting terminal to be adopted, and then correctly realize descrambling.
Description of drawings
Fig. 1 is the existing composition structural representation that produces the linear feedback shift register of binary pseudo-random sequence.
Fig. 2 is the overview flow chart of the inventive method embodiment.
Fig. 3 is the flow chart of the inventive method preferred embodiment.
Fig. 4 is the composition structural representation of apparatus of the present invention embodiment.
Embodiment
Be to solve problems of the prior art, propose a kind of descrambling scheme that is applicable in the CMMB system among the present invention, the initial phase that makes receiving terminal correctly to identify transmitting terminal to be adopted, and then correctly realize descrambling.
Fig. 2 is the overview flow chart of the inventive method embodiment.As shown in Figure 2, may further comprise the steps:
Step 201: from the OFDM symbol that receives, select at least one pair of adjacent OFDM symbol, and from each OFDM symbol wherein, extract an above pilot tone of similar number respectively.
Here the pilot tone of being mentioned that extracts can be a scattered pilot, it also can be continuous pilot, if scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is that two OFDM symbols of 2 are (because in the existing CMMB system that numbering differs, scattered pilot is not all to exist in each OFDM symbol, but occur at interval), if be continuous pilot, then described a pair of adjacent OFDM symbol is meant numbers that to differ be two OFDM symbols of 1.
Step 202: the N kind initial phase that may adopt during according to known scrambling, each pilot tone is carried out descrambling, obtain N kind descrambling result at each pilot tone, N is a positive integer.
In this step, the N kind initial phase that may adopt when utilizing known scrambling calculates the N kind scrambler of each pilot tone correspondence respectively, and utilizes the N kind scrambler that calculates, and respectively each pilot tone is carried out descrambling, to obtain the N kind descrambling result at each pilot tone.
Step 203: according to the N kind descrambling result of each known pilot tone, every pair of OFDM symbol is carried out related operation, obtain N correlated results at every pair of OFDM symbol, and according to N correlated results of every pair of OFDM symbol, calculate final N required energy value, the initial phase that is adopted when wherein maximum value corresponding initial phase is defined as scrambling.
In this step, at every pair of OFDM symbol, handle in such a way respectively: the N kind descrambling result of each pilot tone in one of them OFDM symbol is got conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, and will carry out addition corresponding to each multiplied result of identical initial phase; Then, calculate the energy value of every pair of pairing 8 correlated results of OFDM symbol, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtain final 8 required energy values, the initial phase that is adopted when wherein maximum value corresponding initial phase is defined as scrambling.
Step 204: utilize the initial phase of determining that the OFDM symbol that receives is carried out descrambling.
For making purpose of the present invention, technical scheme and advantage clearer, below with reference to the accompanying drawing preferred embodiment that develops simultaneously, the present invention is described in further detail.
Fig. 3 is the flow chart of the inventive method preferred embodiment.Suppose that the N value in the present embodiment is 8.As shown in Figure 3, may further comprise the steps:
Step 301: receive the OFDM symbol after the scrambling, and extract an above pilot tone of similar number respectively from a pair of adjacent OFDM symbol wherein, described pilot tone is scattered pilot or continuous pilot.
In this step, receiving terminal is therefrom selected a pair of adjacent OFDM symbol after receiving OFDM symbol after the scrambling, extracts the scattered pilot or the continuous pilot of similar number then from these two OFDM symbols respectively.Need to prove that in the present embodiment, what carry out pilot tone to the OFDM symbol and extract and not have clear and definite restriction for concrete selection, are decided by actual needs.For ease of statement, suppose only to select in the present embodiment a pair of, and which specifically selects determining at random.
In addition, in the CMMD system, for receiving terminal, where its each OFDM symbol that receives is in time slot, and the scattered pilot in each OFDM symbol or continuous pilot where all be in be as can be known, so in this step, after receiving terminal receives from the OFDM symbol after the scrambling of transmitting terminal, can therefrom extract required scattered pilot or continuous pilot easily.
Have, the scattered pilot or the continuous pilot number that are comprised in each OFDM symbol all are more usually again, when realizing scheme of the present invention, can extract one or more as required, or even all, to the not clearly restriction of concrete number.
For ease of subsequent descriptions, the pilot tone that extracts is represented in the following manner:
Scattered pilot: Y
n(i); Wherein, i represents the scattered pilot position, and n represents the numbering of OFDM symbol in time slot at scattered pilot place;
Continuous pilot: Y '
n(i); Wherein, i represents the continuous pilot position, and n represents the numbering of OFDM symbol in time slot at continuous pilot place.
Step 302: 8 kinds of initial phases that may adopt during according to known scrambling, calculate 8 kinds of scramblers of each pilot tone correspondence respectively.
Because the position of each pilot tone that extracts all is known, promptly be arranged in which OFDM symbol and belong to this OFDM symbol which effectively subcarrier etc. all be known, so in this step, can calculate 8 kinds of scramblers of each scattered pilot or continuous pilot correspondence respectively according to formula (2) and table 1.
For ease of subsequent descriptions, 8 kinds of scramblers of each pilot tone correspondence of extracting are represented in the following manner:
Scattered pilot: P
n c(i); Wherein, identical in the implication of i and n and the step 301, the value of c is 0,1,2,3,4,5,6 or 7, represents 8 kinds of scramblers;
Continuous pilot: P '
n c(i); Wherein, identical in the implication of i and n and the step 301, the value of c is 0,1,2,3,4,5,6 or 7, represents 8 kinds of scramblers.
Step 303: utilize 8 kinds of scramblers of each pilot tone correspondence, respectively each pilot tone is carried out descrambling, obtain 8 kinds of descrambling results at each pilot tone.
If the pilot tone that extracts is a scattered pilot, then the descrambling mode is:
8 kinds of scramblers that are about to each scattered pilot correspondence are got conjugate operation respectively, and 8 kinds of scramblers getting behind the conjugate operation that each scattered pilot is corresponding with it respectively multiply each other X
n c(i) i.e., 8 kinds of descrambling results calculating of expression;
If the pilot tone that extracts is a continuous pilot, then the descrambling mode is:
8 kinds of scramblers that are about to each continuous pilot correspondence are got conjugate operation respectively, and 8 kinds of scramblers getting behind the conjugate operation that each continuous pilot is corresponding with it respectively multiply each other X '
n c(i) i.e., 8 kinds of descrambling results calculating of expression.
Step 304: 8 kinds of descrambling results of an above pilot tone in one of them OFDM symbol and 8 kinds of descrambling results of an above pilot tone in another OFDM symbol are carried out related operation, obtain 8 correlated results.
In this step, for selected pair of O FDM symbol, 8 kinds of descrambling results of each pilot tone in one of them OFDM symbol are got conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, and will carry out addition corresponding to each multiplied result of identical initial phase.
Said process can be formulated as follows:
Scattered pilot:
Continuous pilot:
Because scattered pilot is just to exist every an OFDM symbol, and continuous pilot is all to exist in each OFDM symbol, so " adjacent " in the formula (5) represented with " n+2 ", " adjacent " in the formula (6) then uses " n+1 " to represent.
After calculating according to the mode of formula (5) and (6), can obtain 8 correlated results: corr (0), corr (1), corr (2), corr (3), corr (4), corr (5), corr (6) and corr (7).
Step 305: calculate the energy value of 8 correlated results, the initial phase that is adopted when the maximum energy value corresponding initial phase is defined as scrambling.
The energy that how to calculate 8 correlated results is a prior art, such as, can calculate the absolute value of 8 correlated results respectively or ask square operation, specific implementation repeats no more.
Because after the scrambler that utilizes correct initial phase to produce carries out descrambling, corresponding energy value will be maximum, so in this step, more resulting 8 energy values, find maximum wherein, and this maximum value corresponding initial phase is defined as the initial phase that adopted when transmitting terminal carries out scrambling.
Step 306: utilize the initial phase of determining that the OFDM symbol that receives is carried out descrambling.
Specifically how descrambling is known in this field, repeats no more.
Need to prove, be that example describes only in embodiment illustrated in fig. 3 to select pair of O FDM symbol to carry out the pilot tone extraction, if how right select, such as three pairs, suppose to be respectively: be numbered 1 and 2 OFDM symbol, the OFDM symbol that is numbered 2 and 3 OFDM symbol and is numbered 3 and 4, so in this case, the specific implementation of step 301～304 is constant (promptly at every pair of OFDM symbol, handling according to process shown in step 301～304 respectively), only in steps 305 of variation.At this moment, need to calculate at first respectively the energy value of every pair of pairing 8 correlated results of OFDM symbol, suppose that the energy value of above-mentioned three pairs of pairing 8 correlated results of OFDM symbol is respectively: A1, A2, A3, A4, A5, A6, A7, A8; B1, B2, B3, B4, B5, B6, B7, B8; C1, C2, C3, C4, C5, C6, C7, C8; Then, with A1, B1 and C1, A2, B2 and C2 ..., A8, B8 and C8 carry out addition respectively, obtain final 8 required energy value D1, D2, D3, D4, D5, D6, D7 and D8; At last, find out these 8 maximums in the final required energy value, the initial phase that is adopted when this maximum value corresponding initial phase is defined as scrambling.
Based on said method, Fig. 4 is the composition structural representation of apparatus of the present invention embodiment.As shown in Figure 4, this device comprises:
Extracting unit 41 is used to receive the OFDM symbol after the scrambling, extracts an above pilot tone of similar number from least one pair of adjacent OFDM symbol wherein respectively;
The first descrambling unit 42, the N kind initial phase that may adopt when being used for according to known scrambling carries out descrambling to each pilot tone, obtains the N kind descrambling result at each pilot tone, and N is a positive integer;
Determining unit 44 is used for the initial phase that is adopted when maximum value corresponding initial phase with final required N energy value is defined as scrambling;
The second descrambling unit 45 is used to utilize the initial phase of determining that the OFDM symbol that receives is carried out descrambling.
The described pilot tone that extracts can be scattered pilot or continuous pilot, if be scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 2 that numbering differs, if be continuous pilot, then described a pair of adjacent OFDM symbol is meant numbers that to differ be two OFDM symbols of 1.
Wherein, can specifically comprise in the first descrambling unit 42:
Can specifically comprise in the computing unit 43:
The 3rd computation subunit 431, be used at every pair of OFDM symbol, N kind descrambling result with each pilot tone in one of them OFDM symbol gets conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, to carry out addition corresponding to each multiplied result of identical initial phase, obtain N correlated results at every pair of OFDM symbol;
The 4th computation subunit 432 is used to calculate the energy value of the every pair of pairing N of OFDM symbol correlated results, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtains final N required energy value.
In the present embodiment, the value of N is generally 8.
The concrete workflow of device embodiment shown in Figure 4 please refer to the respective description among the method embodiment shown in Figure 3, repeats no more.
In a word, adopt technical scheme of the present invention, the initial phase that makes receiving terminal in the CMMB system correctly to identify transmitting terminal to be adopted, and then correctly realize descrambling.
In sum, more than be preferred embodiment of the present invention only, be not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (13)
1. a de-scrambling method is characterized in that, this method comprises:
Receive the orthogonal frequency division multiplex OFDM symbol after the scrambling, from least one pair of adjacent OFDM symbol wherein, extract an above pilot tone of similar number respectively;
The N kind initial phase that may adopt during according to known scrambling carries out descrambling to each pilot tone, obtains the N kind descrambling result at each pilot tone; Described N is a positive integer;
According to described N kind descrambling result at each pilot tone, every pair of OFDM symbol is carried out related operation, obtain N correlated results at every pair of OFDM symbol; And according to described N correlated results, calculate final N required energy value, the initial phase that is adopted when wherein maximum value corresponding initial phase is defined as scrambling at every pair of OFDM symbol;
The initial phase that utilization is determined carries out descrambling to the OFDM symbol that receives.
2. method according to claim 1, it is characterized in that, described pilot tone is scattered pilot or continuous pilot, if be scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 2 that numbering differs, if be continuous pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 1 that numbering differs.
3. method according to claim 1 is characterized in that, the described N kind initial phase that may adopt during according to known scrambling carries out descrambling to each pilot tone, obtains comprising at the N kind descrambling result of each pilot tone:
The N kind initial phase that may adopt during according to known scrambling calculates the N kind scrambler of each pilot tone correspondence respectively;
Utilize the N kind scrambler of each pilot tone correspondence, each pilot tone is carried out descrambling, obtain N kind descrambling result at each pilot tone.
4. method according to claim 3 is characterized in that, describedly each pilot tone is carried out descrambling comprises:
The N kind scrambler of each pilot tone correspondence is got conjugate operation respectively;
The N kind scrambler of getting behind the conjugate operation that each pilot tone is corresponding with it respectively multiplies each other.
5. method according to claim 1 is characterized in that, described every pair of OFDM symbol is carried out related operation, obtains comprising at N correlated results of every pair of OFDM symbol:
The N kind descrambling result of each pilot tone in one of them OFDM symbol is got conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, will carry out addition corresponding to each multiplied result of identical initial phase.
6. method according to claim 1 is characterized in that, and is described according to described N correlated results at every pair of OFDM symbol, calculates final N required energy value and comprises:
Calculate the energy value of the every pair of pairing N of OFDM symbol correlated results respectively, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtain final N required energy value.
7. method according to claim 6 is characterized in that, the energy value of every couple of pairing N of OFDM symbol of described calculating correlated results comprises:
Calculate the absolute value of a described N correlated results respectively; Perhaps, calculate respectively a described N correlated results square.
8. according to each described method in the claim 1～7, it is characterized in that the value of described N is 8.
9. a descrambler is characterized in that, this device comprises:
Extracting unit is used to receive the orthogonal frequency division multiplex OFDM symbol after the scrambling, extracts an above pilot tone of similar number from least one pair of adjacent OFDM symbol wherein respectively;
The first descrambling unit, the N kind initial phase that may adopt when being used for according to known scrambling carries out descrambling to each pilot tone, obtains the N kind descrambling result at each pilot tone; Described N is a positive integer;
Computing unit is used for according to described N kind descrambling result at each pilot tone every pair of OFDM symbol being carried out related operation, obtains N correlated results at every pair of OFDM symbol; And, calculate final N required energy value according to described N correlated results at every pair of OFDM symbol;
Determining unit is used for the initial phase that is adopted when maximum value corresponding initial phase with described final required N energy value is defined as scrambling;
The second descrambling unit is used to utilize the described initial phase of determining that the OFDM symbol that receives is carried out descrambling.
10. device according to claim 9, it is characterized in that, described pilot tone is scattered pilot or continuous pilot, if be scattered pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 2 that numbering differs, if be continuous pilot, then described a pair of adjacent OFDM symbol is meant that it is two OFDM symbols of 1 that numbering differs.
11. device according to claim 9 is characterized in that, the described first descrambling unit comprises:
First computation subunit, the N kind initial phase that may adopt when being used for according to known scrambling calculates the N kind scrambler of each pilot tone correspondence respectively;
Second computation subunit is used for the N kind scrambler of each pilot tone correspondence is got conjugate operation respectively, and the N kind scrambler of getting behind the conjugate operation that each pilot tone is corresponding with it respectively multiplies each other, and obtains the N kind descrambling result at each pilot tone.
12. device according to claim 9 is characterized in that, described computing unit comprises:
The 3rd computation subunit, be used at every pair of OFDM symbol, N kind descrambling result with each pilot tone in one of them OFDM symbol gets conjugate operation respectively, and with each pilot tone get behind the conjugate operation every kind of descrambling result respectively with another OFDM symbol in the pilot tone of correspondence position the descrambling result corresponding to identical initial phase multiply each other, to carry out addition corresponding to each multiplied result of identical initial phase, obtain N correlated results at every pair of OFDM symbol;
The 4th computation subunit is used to calculate the energy value of the every pair of pairing N of OFDM symbol correlated results, and each is carried out addition to the energy value corresponding to identical initial phase in the OFDM symbol, obtains final N required energy value.
13., it is characterized in that the value of described N is 8 according to each described device in the claim 9～12.
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| CN1286534A (en) * | 1999-11-10 | 2001-03-07 | 深圳市中兴通讯股份有限公司 | Channel estimating method used in WCDMA receiver |
| CN1756411A (en) * | 2004-09-29 | 2006-04-05 | 中兴通讯股份有限公司 | WCDMA system access channel frequency deviation estimating method |
| CN1885846A (en) * | 2006-05-22 | 2006-12-27 | 北京北方烽火科技有限公司 | Orthogonal frequency-division multiplexing system and selective mapping transmitting and receiving method |
| CN101119352A (en) * | 2006-12-19 | 2008-02-06 | 华为技术有限公司 | OFDM based signal receiving and dispatching method and apparatus |
| CN101223703A (en) * | 2005-07-20 | 2008-07-16 | Nxp股份有限公司 | Method for reception of DVB-H signals and DVB-H receiver |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1286534A (en) * | 1999-11-10 | 2001-03-07 | 深圳市中兴通讯股份有限公司 | Channel estimating method used in WCDMA receiver |
| CN1756411A (en) * | 2004-09-29 | 2006-04-05 | 中兴通讯股份有限公司 | WCDMA system access channel frequency deviation estimating method |
| CN101223703A (en) * | 2005-07-20 | 2008-07-16 | Nxp股份有限公司 | Method for reception of DVB-H signals and DVB-H receiver |
| CN1885846A (en) * | 2006-05-22 | 2006-12-27 | 北京北方烽火科技有限公司 | Orthogonal frequency-division multiplexing system and selective mapping transmitting and receiving method |
| CN101119352A (en) * | 2006-12-19 | 2008-02-06 | 华为技术有限公司 | OFDM based signal receiving and dispatching method and apparatus |
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