CN1574827A - Frequency offset estimator of multi-carrier receiver and frequency offset estimating method - Google Patents
Frequency offset estimator of multi-carrier receiver and frequency offset estimating method Download PDFInfo
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- CN1574827A CN1574827A CNA200410049647XA CN200410049647A CN1574827A CN 1574827 A CN1574827 A CN 1574827A CN A200410049647X A CNA200410049647X A CN A200410049647XA CN 200410049647 A CN200410049647 A CN 200410049647A CN 1574827 A CN1574827 A CN 1574827A
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- power
- frequency
- frequency offset
- signal
- frequency shift
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2657—Carrier synchronisation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2666—Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length
-
- 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
- H04L27/2668—Details of algorithms
- H04L27/2669—Details of algorithms characterised by the domain of operation
- H04L27/2672—Frequency domain
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
- H04L2027/0026—Correction of carrier offset
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Circuits Of Receivers In General (AREA)
- Noise Elimination (AREA)
Abstract
The invention relates to a frequency deflection estimator of the multi-carrier receiver and the method, which are used to estimate frequency deflection and make use of a protective belt inserted in the frequency domain to minimize the damage to the sub-carrier signal. The frequency deflection estimator comprises at least a pair of power calculating units and a summation unit; wherein, the power calculating units are used to calculate the power of at least a pair of guard interval signals inserted in the code element; the summation unit is used to determine the frequency deflection according to the power calculated by at least a pair of power calculating units. Therefore, the GB at both ends of the multi-carrier in the frequency domain can be used to estimate frequency deflection, so as to simplify the realization of the attached receiver.
Description
Technical field
The present invention relates generally to a kind of frequency offset estimator of multi-carrier receiver.More specifically, the present invention relates to a kind of use is inserted in the frequency domain so that to the minimized protection of the destruction of subcarrier frequency offset estimator and frequency offset estimation methods thereof at interval.
Background technology
OFDM (OFDM) transmitter, this transmitter sends ofdm signal by the Domain Synchronous of using the multicarrier transmission technology, by inverse fourier transform with the signal scrambling code in frequency domain and the time domain.For fear of inter symbol interference about the signal of conversion in the time domain, insert protection at interval, then with pseudo noise (PN) sequence, promptly synchronizing sequence is inserted in the signal that has inserted protection time domain at interval.Because the signal with PN sequence has the form of impulse wave, the band occupancy with the impulse wave of PN sequence and signal in the time domain that is assigned with correspondingly by pulse shaping filter by shaping and filtering.The signal of shaping and filtering is amplified with transmission by high frequency.
Carry out the pulse shaping filter of the multicarrier transmitting system that Domain Synchronous (TDS) sends will have the PN sequence by the roll-off factor that is provided with pulse wave form signal shaping and filtering.As a result, destroyed in the data of the edge of a pulse and the data that may can not recover to send at receiving terminal.
In order to solve above-mentioned shortcoming, the applicant discloses the 10-2002-33271 Korean Patent that is entitled as " can stablize the OFDM transmitter (OFDM transmitter capable of stably transmitting OFDM symbols) that sends ofdm signal ".
Fig. 1 is the block diagram that is illustrated in disclosed OFDM transmitting system in the 10-2002-33271 Korean Patent.Fig. 2 represents to have the example that inserts the signal of the boundary belt that inserts the unit by GB.
As shown in fig. 1, transmitting system comprises that the GB that GB is inserted in the signal of frequency domain inserts unit 140.If multi sub-carrier count be made as shown in Figure 2 3780, then GB place 0 and 189 between or 3591 and 3779 between, the ofdm signal data place 190 and 3590 between.
Fig. 3 is that expression is the waveform of the OFDM code element with GB of 0.1 pulse shaping filter filtering by roll-off factor.As shown in Figure 3, because two edges of ofdm signal data are all filtered, so the ofdm signal data do not have destroyed and can be in the receiving terminal stable reproduction.
The GB that is contained in the multi-carrier signal can make because the destruction that pulse shaping filter causes minimizes.
Therefore, if receiver is designed to use the GB processing signals, then can have higher efficient.
Summary of the invention
In order to solve above-mentioned shortcoming, an aspect of of the present present invention is to provide a kind of frequency offset estimator and frequency offset estimation methods thereof that is contained in the multi-carrier receiver of the protection interval estimated frequency skew in the multi-carrier signal by use.
In order to realize above-mentioned aspect of the present invention, frequency offset estimator comprises: at least one pair of power calculation unit, be used to calculate power about boundary belt, and this boundary belt is inserted at least a portion of the multi-carrier signal in the frequency domain; And addition unit, be used for by using the power that calculates by a pair of or more power calculation unit to determine frequency shift (FS).
According to a further aspect in the invention, frequency offset estimator comprises: first power calculation unit is used for calculating first power about the signal of first boundary belt of the multi-carrier signal front end that is inserted into frequency domain; Second power calculation unit is used for calculating second power about the signal of second boundary belt of the multi-carrier signal end that is inserted into frequency domain; And addition unit, be used for determining frequency shift (FS) by the difference power that calculates between first power and second power.First and second boundary belts have identical length.
If the difference power that calculates be on the occasion of, then addition unit is determined frequency shift (FS) and is present in positive direction; If the difference power that calculates is a negative value, then addition unit is determined frequency shift (FS) and is present in negative direction.
A kind of frequency offset estimation methods is provided, has comprised step: measured power about the boundary belt of at least a portion of being inserted into the multi-carrier signal in the frequency domain; Determine frequency shift (FS) with the one or more power of use.
Therefore, can realize independent receiver more easily by the boundary belt estimated frequency skew of using the multi-carrier signal both sides in the frequency domain.
Description of drawings
By the description of embodiment being carried out below in conjunction with accompanying drawing, these and/or other aspect of the present invention and advantage will become clear and be easier to and understand, wherein:
Fig. 1 is the block diagram of the conventional multicarrier transmitter of expression;
Fig. 2 inserts the unit by the GB among Fig. 1 to insert the protection example of the signal of (GB) at interval;
Fig. 3 is by the waveform of the signal with GB among Fig. 1 of pulse shaping filter filtering;
Fig. 4 is the block diagram of frequency offset estimator of the multi-carrier receiver of expression specific embodiment of the present invention;
Fig. 5 is the flow chart of the frequency offset estimation methods of the frequency offset estimator in the presentation graphs 4; With
Fig. 6 A to 6C is the schematic diagram of expression Frequency offset estimation, and wherein, the frequency offset estimator among Fig. 4 uses a plurality of GB.
Embodiment
With reference to accompanying drawing the present invention is described in more detail.
Fig. 4 is the block diagram of the frequency offset estimator of expression specific embodiment of the present invention.
Frequency offset estimator 400 comprises first power calculation unit 410, second power calculation unit 430, addition unit 450 and loop filter 470.
Signal from the frequency domain of Fourier transformation unit 300 outputs has first and second boundary belts (GB) of predetermined number at two ends.
First power that first power calculation unit 410 is calculated about the signal of the GB in the frequency domain.
Second power that second power calculation unit 430 is calculated about the signal of the 2nd GB in the frequency domain.
Addition unit 450 is calculated the difference between first power and second power and is determined frequency shift (FS) based on the difference power that calculates.
Loop filter 470 carries out the difference power that filtering calculates with elimination, that is, and and frequency shift (FS).
Owing to the length of first and second GB that insert at transmitting terminal is identical, if there is not frequency shift (FS), the data of first and second GB have identical performance number.Specifically, if there is not frequency shift (FS), the difference power between first and second GB becomes ' 0 ', if there is frequency shift (FS), then difference power may on the occasion of or negative value.Therefore, be offset according to the difference power estimated frequency between first and second GB.
Multi-carrier receiver is offset by generating corresponding to digital controlled oscillator (NCO) value of estimated frequency shift and with its input signal compensating frequency that multiply by in the compensating unit 200.
Fig. 5 is the flow chart of frequency offset estimation methods of the multi-carrier receiver of expression specific embodiment of the present invention.With reference to Fig. 5 and 6A to 6C, the more detailed description frequency offset estimation methods.
As shown in Figure 6A, behind the Fourier transform, the signal two ends in frequency domain include first and second GB.
At step S510, first and second power calculation unit 410,430 are calculated first and second power of first and second GB respectively.
At step S530, addition unit 450 is calculated the difference between first and second power that calculated and is determined frequency shift (FS).
If the difference power that calculates by addition unit 450 be on the occasion of, then frequency shift (FS) is present in the positive direction shown in Fig. 6 B.
If difference power is a negative value, then frequency shift (FS) is present in the negative direction shown in Fig. 6 C.
At step S550, loop filter 470 is with the difference power filtering that calculates.
The frequency shift (FS) that estimates is converted into corresponding N CO value and multiply by the signal of being imported by compensating unit 200 and is offset with compensating frequency.Specifically, if frequency shift (FS) for just, then frequency shift (FS) is compensated in negative direction; If frequency shift (FS) is for negative, then frequency shift (FS) is compensated in positive direction.The difference that frequency offset compensation will carry out continuously between second power of first power of a GB and the 2nd GB becomes ' 0 ', or is ' 0 ' substantially.
As a result, by using the destruction to data of GB estimated frequency skew to prevent to cause of inserting by pulse shaping filter.In addition, the estimated frequency skew does not need the realization of independent hardware.
According to above-mentioned some embodiments of the present invention, by using the GB estimated frequency skew at the multi-carrier signal two ends in the frequency domain, thereby simplified the realization of additional receiver.
Although represented and described some embodiments of the present invention, the invention is not restricted to above-mentioned disclosed embodiment.On the contrary, it should be appreciated by those skilled in the art, do not breaking away from aim of the present invention and spirit, and under the situation by claim and equivalent institute restricted portion thereof, can change and revise embodiment.
Claims (8)
1, a kind of reception comprises the frequency offset estimator of the multi-carrier receiver of the protection multi-carrier signal at interval that is used to stop inter symbol interference, comprising:
At least one pair of power calculation unit is used for calculating the power about at least one pair of protection signal at interval that inserts in code element; With
Addition unit is used for by using the power that is calculated by at least one pair of power calculation unit to determine frequency shift (FS).
2, a kind of reception comprises the frequency offset estimator of the multi-carrier receiver of the protection multi-carrier signal at interval that is used to stop inter symbol interference, comprising:
First power calculation unit is used to calculate first power about the signal of first boundary belt that inserts at the code element front end;
Second power calculation unit is used to calculate about second power at the signal of terminal second boundary belt that inserts of code element; With
Addition unit is used for determining frequency shift (FS) by the difference power that calculates between first power and second power.
3, frequency offset estimator as claimed in claim 2, wherein, first and second boundary belts have equal length.
4, frequency offset estimator as claimed in claim 2, wherein, if the difference power that calculates be on the occasion of, then addition unit determines that frequency shift (FS) is present in positive direction; If the difference power that calculates is a negative value, then addition unit determines that frequency shift (FS) is present in negative direction.
5, a kind of reception comprises the frequency offset estimation methods of the multi-carrier receiver of the protection multi-carrier signal at interval that is used to stop inter symbol interference, comprising:
Measurement is about the power of the boundary belt of at least a portion of being inserted into the multi-carrier signal in the frequency domain; With
Determine frequency shift (FS) by using the one or more power that calculates.
6, a kind of reception comprises the protection frequency offset estimation methods of the multi-carrier receiver of multi-carrier signal at interval that is used to stop inter symbol interference, comprising:
Measurement is about first power of first boundary belt of the front end that is inserted into the multi-carrier signal in the frequency domain;
Measurement is about second power of second boundary belt of the end that is inserted into the multi-carrier signal in the frequency domain.With
Determine frequency shift (FS) by the difference power that calculates between first and second power.
7, method as claimed in claim 6, wherein, first and second boundary belts have equal length.
8, method as claimed in claim 6, wherein, in determining frequency shift (FS), if the difference power that calculates be on the occasion of, determine that then frequency shift (FS) is present in positive direction; If the difference power that calculates is a negative value, determine that then frequency shift (FS) is present in negative direction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR40876/2003 | 2003-06-23 | ||
| KR1020030040876A KR20050000264A (en) | 2003-06-23 | 2003-06-23 | Frequency offset estimator of multi carrier receiver and a method frequency offset estimating thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1574827A true CN1574827A (en) | 2005-02-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA200410049647XA Pending CN1574827A (en) | 2003-06-23 | 2004-06-23 | Frequency offset estimator of multi-carrier receiver and frequency offset estimating method |
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| Country | Link |
|---|---|
| KR (1) | KR20050000264A (en) |
| CN (1) | CN1574827A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103368878A (en) * | 2013-07-22 | 2013-10-23 | 苏州英菲泰尔电子科技有限公司 | Bluetooth 4.0 low-power-consumption high-precision frequency offset estimating device and method |
-
2003
- 2003-06-23 KR KR1020030040876A patent/KR20050000264A/en not_active Application Discontinuation
-
2004
- 2004-06-23 CN CNA200410049647XA patent/CN1574827A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103368878A (en) * | 2013-07-22 | 2013-10-23 | 苏州英菲泰尔电子科技有限公司 | Bluetooth 4.0 low-power-consumption high-precision frequency offset estimating device and method |
| CN103368878B (en) * | 2013-07-22 | 2016-08-24 | 苏州英菲泰尔电子科技有限公司 | The devices and methods therefor that bluetooth 4.0 low power consumption high-precision frequency deviation is estimated |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20050000264A (en) | 2005-01-03 |
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