CN1682508A - Iterative estimation and equalization of asymmetries between inphase and quadrature branches in multicarrier transmission systems - Google Patents

Iterative estimation and equalization of asymmetries between inphase and quadrature branches in multicarrier transmission systems Download PDF

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CN1682508A
CN1682508A CN 03821378 CN03821378A CN1682508A CN 1682508 A CN1682508 A CN 1682508A CN 03821378 CN03821378 CN 03821378 CN 03821378 A CN03821378 A CN 03821378A CN 1682508 A CN1682508 A CN 1682508A
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channel
data symbol
distortion parameter
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L·布雷杰
K·-D·坎梅耶
V·科赫恩
S·沃格勒
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Infineon Technologies AG
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/36—Modulator circuits; Transmitter circuits
    • H04L27/362—Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated
    • H04L27/364—Arrangements for overcoming imperfections in the modulator, e.g. quadrature error or unbalanced I and Q levels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03159—Arrangements for removing intersymbol interference operating in the 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
    • H04L2027/0016—Stabilisation of local oscillators
    • 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

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  • Computer Networks & Wireless Communication (AREA)
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  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
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Abstract

Distortions of radio signals transmitted in data blocks in an OFDM method, the distortions being caused by transmitter- or receiver-end IQ asymmetries and by channel distortion, can be estimated and equalized by means of an iteration method. The method can be used particularly advantageously in a direct-mixing receiver.

Description

Asymmetric iteration assessment, equilibrium between homophase and orthogonal branches in the tds-ofdm transmission system
Technical field
The invention relates to a kind of method that is used to estimate with the correcting wireless distorted signals, wherein the wireless signal distortion is by reflector or receiver and IQ is asymmetric and by channel distortion and form, described wireless signal is with the emission of multicarrier launching technique, and the invention relates to the device that carries out described method.
Background technology
In European DVB (digital photography broadcasting) system, developed the digital transmission system that is used for satellite (DVB-S), wired (DVB-C) and is used for received terrestrial digital broadcasting emission (DVB-T), and existing well-designed corresponding specification.Because at the existing problematic launching condition of terrestrial wireless channel, so be OFDM launching technique (orthogonal frequency division multitask) in the launching technique of DVB-T specification defined, it can effectively resist the launching condition of difficulty.
Another important applied field of described OFDM launching technique is the high-speed radio transmit network, for example WLAN (wireless district network), particularly defined launching technique in standard IEEE 802.11a and 11g and HIPERLAN/2.
Described OFDM launching technique is a multicarrier launching technique, and wherein splitting traffic between many parallel (quadrature) subcarrier wherein is to adjust subcarrier by low relatively data speed.As shown in Figure 1, dispose (inferior) carrier frequency, thereby wear among the wide K in an emission, described (inferior) carrier frequency is each other at a distance of same distance.Described carrier frequency is the both sides that are symmetrically located at a centre frequency f.In time zone, the replacement of all k carrier frequencies forms the OFDM symbol.In frame form or breach (burst), finish described data transmission, a frame is the OFDM symbol that comprises similar number.
Based on the known reception notion of the heterodyne reception principle of mixing, can finish the reception and the demodulation of OFDM wireless signal with follow-up digital quadrature.Yet, suppress for image frequency, reduce power consumption and the main cause of avoiding chip-external filter, more and more useful reception notion is to use the method for directly mixing.Directly mixing in the receiver notion, receive with the wireless signal that amplifies by an antenna and to be divided into homophase (I) and quadrature (Q) branch, and mix with the output frequency of a regional oscillator in two branches, the oscillator frequency of described blender is delivered in reciprocal 90 degree skews by a phase deviation device.So, receive in the notion at this, use Analogical Circuit Technique, carry out described quadrature demodulation or reclaim described information-bearing baseband signal.
The incorrectness of joining known to stating in the processing procedure product and the imperfection of analog mixer and oscillator, and filter described in I and the Q branch and between error, cause the asymmetric or IQ distortion (distortion) of so-called IQ, that is the asymmetry of amplitude and phase place between the quadrature component.The real part of described complex base band signal and imaginary part are not actual each other phase deviation 90 degree, and the amplitude error between I branch and Q branch more takes place.In described reflector and described receiver, this IQ asymmetry all can take place.In described receiver, in system based on OFDM, described IQ asymmetry, in frequency field, that is in described receiver, FFT conversion (fast fourier transform; Fast Fourier Transform) afterwards, cause the reciprocal interference between two data symbols on the subcarrier, about the load frequency fc of described OFDM frequency spectrum, described sub-carrier frequencies be balanced configuration (after this be called subcarrier n with-n).Because added IQ asymmetry in time zone, each data symbol of being launched on described subcarrier n produces the subcarrier of a signal contribution in pointer-n (imaginary part frequency).Described replacement is formed on the distortion of position n and-n useful signal.
In Andreas Schuchert paper " digital compensation method of hybrid analog-digital simulation quadrature asymmetry in the OFDM receiver " chapter 4 that Bergische Universit  t-Ges amthochschule Wuppertal electronic engineering and information technology system is accepted, propose the mathematical description of IQ asymmetry and be provided at institute to desire the video quantitative estimation of the interference contribution that frequency took place of signal.Chapter 6 in the above-mentioned paper proposes two kinds of diverse ways, by the frequency field equilibrium, and is used for the compensation of IQ mistake.The first method that is proposed is the individual frequencies independent compensation of IQ asymmetry.For detecting equalizing coefficient by an IQ error detector, also proposing to use pilot frequency carrier wave (pilot carrier), its emission is to estimate to believe that translation function becomes the purpose of training symbol in order to reach, and reaches the purpose of estimating I/Q distortion.Yet the circuit arrangement that is used for two method faults compensation has very many functional blocks and thereby has a high execution cost.
WO 02/056523 discloses another kind of method, and it can get rid of reflector and receiver end IQ asymmetry.The basis of the method is to produce compensating signal, is used in compensation corresponding to described IQ mistake and with it.
Summary of the invention
Therefore, the equalization methods that the purpose of this invention is to provide estimation approach and subsequent wireless signal distortion, it is by tds-ofdm transmission system, the reflector in the OFDM emission system or receiver end IQ asymmetry causes particularly, and provide and carry out the lower corresponding intrument of described method cost.
Reach purpose of the present invention by the feature in the claim independent entry, described claim advocates to estimate the method with correct transmission device end and receiver end IQ asymmetry respectively.Moreover the device of these methods is carried out in proposition.Favourable development of the present invention and modification are to be described in the described claim dependent claims.
The invention relates to the method that is used to estimate with the correcting wireless distorted signals, the distortion of described wireless signal caused by reflector or receiver end IQ asymmetry, be that wireless signal is the multicarrier emission in frame or breach formal approach and launching.Described method can be used in all spectra, in can use the multicarrier launching technique, that is in wireless data transmission network (WLAN) field or in the field of digital ground photography or voice signal emission.The frequency spectrum of described multicarrier launching technique comprises about centre frequency fc and the subcarrier n and the subcarrier-n of symmetrical spectrum configuration.
As mentioned above, the distortion of key of the present invention (distortion) is included in the interference between the monosymmetric subcarrier of multicarrier frequency spectrum centre frequency fc.By the asymmetry of reflector and receiver end IQ and form this distortion.Moreover the multipath propagation of described wireless channel (multipathpropagation) forms the linear distortion of subcarrier.Comprise the whole distortion of IQ distortion and channel distortion, can carry out emulation by following equation:
Figure A0382137800091
In described example,
Figure A0382137800092
Be the distorted symbols that is received in described subcarrier n at i, d n(i) be undistorted emission symbol, A TXForm described emitter terminals IQ distortion matrix, A RXForm receiving terminal IQ distortion matrix, and C comprises the channel coefficients of multi-path channel.
Basis of the present invention is known described emitter terminals or described receiver end IQ asymmetry.So, if known described IQ distortion matrix (A RXOr A TX) one of them, but then iteration (iteratively) is estimated the coefficient and the channel coefficients C of another IQ distortion matrix, and simultaneously can be balanced and decision with the symbol that is received.In this example, in one, handle the multicarrier data symbol (for example OFDM symbol) that is received.As a result, in each iteration (iteration) loop, handle a data block that comprises OFDM symbol group, and channel coefficients and iteration are used for this groups of data symbols by the IQ distortion parameter that (iteration pass) end is determined.This groups of data symbols then is called data block, can be the inferior group of frame or breach (burst).Yet, depend on the definition of notch length in the acceptance criteria, well imagine that described data block is corresponding to described frame.
At first use emitter terminals IQ mistake (A TX) estimation with proofread and correct example, be described as follows.Estimate earlier and the described receiving terminal IQ distortion matrix (A of correction by suitable measurement RX).
Because approximation a n TX, a n TX, equation (1) becomes
d ^ n ′ ( i ) d ^ - n ′ * ( i ) = C n 0 0 C - n * · 1 b n TX b - n TX * 1 · d n ( i ) d - n * ( i ) - - - ( 2.1 )
By described channel coefficients C n, C -nKnowledge, described IQ distortion matrix A TXThe decision of surplus variable can by
b ^ n TX = d ^ n ′ ( i ) - C n · d n ( i ) C n · d - n * ( i )
b ^ - n TX = d ^ - n ′ ( i ) - C - n · d - n ( i ) C - n · d n * ( i ) - - - ( 2.2 )
According to the present invention, be used on this basis estimate and the first method of proofreading and correct described emitter terminals IQ asymmetry.According to the present invention, described first method common form, at first be method step a, with from the channel coefficients that previous data block was determined, and with the received data symbol equilibrium of first data block.In method step b, follow-up by the temporary transient IQ distortion parameter that previous data block determined, and with described data symbol equilibrium.In this mode, then in step c, will be provided to the symbol determination procedure by the data symbol of equilibrium.In steps d, reference signal that is provided by described symbol determination procedure and the symbol that is received are to be used for channel estimating, are used to produce new signal coefficient.At last, in method step e, estimate reference symbol and the new channel coefficients that data symbol was determined that is received, estimate new IQ distortion parameter to state signal.
As the data block of the specified received data symbol of first data block, be the arbitrary data piece (arbitrary data block) that is defined as wireless signal transmission.Designing first data block only distinguishes as language idendification and from second data block of temporary connection.
Being actually the described wireless transmission data block of first data block according to the time, is to be designed to the initial data piece.In the example of this initial data piece, owing to do not have the data block of temporary transient processing, so can't initially carry out the method according to this invention in the identical mode of all subsequent data blocks.Can be in step a and b, the data symbol equilibrium that is received in the described initial data piece will be included in, therefore on the basis of pilot signal (pilot signal), carry out a channel estimating, normally be contained in the front portion (preamble) of the affiliated corresponding data breach of described initial data piece.In described method step a,,, and in step b, described IQ distortion parameter setting is equalled zero the data symbol equilibrium that is received with from the channel coefficients that described channel estimating was determined.
In described method step d and e, determined after new channel coefficients and the new IQ distortion parameter, in the method according to this invention, can carry out another iteration (iteration) step, wherein by described new channel coefficients and described new IQ distortion parameter, for temporary connection is the received data symbol of second data block of first data block, repeating step a to e (method step f), and with the new channel coefficients that determined among the method step f and new IQ distortion parameter, and with the received data symbol equilibrium (method step g) of described first data block.
In addition, in step f, also can be provided at the new channel coefficients and new IQ distortion parameter that determine among method step d and the e, for the received data symbol of first data block, repetition methods step a to e.Thereby, based on first data block or the data block of temporary connection, optionally carry out this iterative step and other iterative step, be used to upgrade described channel coefficients and described IQ distortion parameter.
Aforesaid iteration is used to upgrade described channel coefficients and IQ distortion parameter with method step f and g, if suitably, then then passes through other iterative step of method step a to e.After last iterative step terminal is provided, by the channel coefficients and the IQ distortion parameter that have upgraded at last, and with the data symbol equilibrium that is received, and provide to described symbol determination procedure, and the data symbol that is determined is next processing unit that is output to described receiver.
In method step d, produce described channel coefficients, since from a channel estimating the channel coefficients that determined, its basis is that described symbol determination procedure reference symbol that provides and the data symbol that is received are to be used for and the old numerical value weighted average of channel coefficients, thereby, can reappraise IQ mistake according to equation (2.2) based on the data symbol that is received among average channel coefficients, reference symbol and the method step e.(IQ tracking)
More can in method step, provide and produce new IQ distortion parameter, because the new channel coefficients that the basis of the described IQ distortion parameter of decision is in channel estimation process to be determined, average described reference symbol and the data symbol that received and previous iterative step in the IQ distortion parameter of one or more steps decisions.
If before another advantage is that the channel estimating in method step is carried out,, carry out the IQ predistortion (predistortion) of the reference symbol that provided by the symbol determination procedure based on the IQ distortion parameter that upgrades.This EQ predistortion of described reference symbol makes and can significantly reduce misjudgment owing to described IQ distortion.
According to second method of the present invention, as the estimation and the correction of described receiver end IQ asymmetry.Carry out from equation (1) once more, suppose to have estimated by suitable measurement in advance and proofreaied and correct described emitter terminals IQ distortion matrix (A TX).
By approximation a n TX, a n TXAnd known channel coefficients C n, C -n, described IQ distortion matrix A RXSurplus variable can be by the decision of following equation
b ^ n RX = d ^ n ′ ( i ) - C n · d n ( i ) C - n · d - n * ( i )
b ^ - n RX = d ^ - n ′ ( i ) - C - n · d - n ( i ) C n · d n * ( i ) - - - ( 3.1 )
Second method according to the present invention is on this basis, carries out the estimation and the correction of described receiver end IQ asymmetry.According to the present invention in the prevailing form of second method, at first, in method step a, by the IQ distortion parameter that data block determined from a temporary connection, and the data symbol equilibrium that first data block is received.Then provide data symbol to be used for channel estimating, be used for producing new channel coefficients, then in method step c, by the channel coefficients that is determined and with described data symbol equilibrium at method step b.Then, with in this way balanced data symbol symbol determination procedure to the method step d is provided.Then, in method step e,, carry out IQ and estimate, and provide correcting circuit to IQ with the IQ distortion parameter that is determined based on the reference symbol that provided by the symbol determination procedure and by the channel coefficients that described channel estimating was provided.
Description of drawings
According to the present invention, carry out described method and the embodiment that carries out the corresponding intrument of described method, as described below, and see also the accompanying drawing of being attached.
Fig. 1 is the frequency spectrum of explanation OFDM launching technique.
Fig. 2 is explanation one a receiver end block circuit arrangement, is used to carry out the method according to this invention, is used for the estimation and the correction of emitter terminals IQ asymmetry.
Fig. 3 is explanation one a receiver end block circuit arrangement, is used to carry out the method according to this invention, is used for the estimation and the correction of receiver end IQ asymmetry.
Embodiment
In the embodiment shown in Figure 2, wherein employed variable is about the estimation of an emitter terminals IQ asymmetry and correction, described channel coefficients C n, C -n, and determine described IQ distortion parameter
Figure A0382137800131
With
Figure A0382137800132
Needed emission symbol d n(i) and d -n(i) (equation (2.2)).
Be contained in the receiver and device as shown in Figure 2, present the data symbol that is received
Figure A0382137800133
Described data symbol is included in the data block.A plurality of data blocks form a frame, and each frame has anterior symbol
Figure A0382137800134
By the formed data symbol of OFDM among the embodiment, be to be fed to the impartial device 2 of a channel, wherein be with by channel coefficients that described previous data block was determined and with its equilibrium.
Then the data symbol of equilibrium being delivered to an IQ Error-Correcting Circuit 3, wherein is with the IQ distortion parameter b by described previous data block was determined n TX, b -n TXAnd carry out an IQ error correction.
The data symbol that then described equilibrium and IQ proofread and correct is sent to symbol decision unit 4, and it has two inputs.After described symbol decision, there is new reference symbol to be used for all subcarrier n/-n, and first output that exports described symbol decision unit 4 to.
At the received data symbol In the channel estimator of being delivered to 6,, carry out new channel estimating based on these reference symbols.The reference symbol of described symbol decision 4 confessions in unit is delivered to an IQ predistorter 5, the IQ distortion parameter b that is wherein upgraded TXBe to be sent to described IQ predistorter 5.Because described IQ distortion, described IQ predistortion reduces misjudgment.
Be provided at the channel coefficients that is calculated in the channel estimator 6, and with old numerical value weighted average, thereby on the basis of these average channel coefficients, reference symbol and reception value, can in an IQ tracking cell 7, reappraise described IQ mistake, wherein receiving symbol
Figure A0382137800136
Be to deliver to described IQ tracking cell 7.Estimating for each subcarrier that can get
Figure A0382137800137
With Afterwards, can in time orientation (by an iteration piece), carry out the average of these values, to reach the purpose that reduces noise.Then, with the value average (weighted average) of previous iteration in the value of these estimations and the averaging unit 8.
Then, carry out new iteration (iteration) by delivering to the impartial device 2 of described channel and the described channel coefficients of described IQ correcting circuit 3 and the updating value of IQ distortion parameter.Can use the data block of the reception OFDM symbol of the present data block of temporary connection, carry out described iteration.Yet available identical reception data block is the basis, improves estimated value by multiple iteration.
For initial described parameter, in first iteration (it=0) before, based on reference data, the symbol of in a front portion (preamble), being launched for example As shown in Figure 2, finish the OFDM channel estimating.Suppose b n TX , b - n TX = 0 Be the initial value of the IQ distortion parameter of IQ correcting circuit 3, thereby described IQ correction (with described IQ predistortion) keep invalid in described first iteration.Yet, also can be by the suitable estimated initial of described IQ distortion parameter, and improve the of short duration reaction of control.
Embodiment shown in Fig. 3 and employed variable wherein are estimation and the corrections about a receiver end IQ asymmetry, With
Figure A0382137800143
Equation (3.1) is as the basis of the described IQ distortion parameter of decision.
The device that is included in the receiver end shown in Fig. 3 is received data symbol
Figure A0382137800144
At first described data symbol is delivered to an IQ correcting circuit 10, wherein carrying out the basis that an IQ proofreaies and correct is to be the IQ distortion parameter, and the basis of its decision is the previous iteration passed through based on more preceding groups of data symbols.
Then described IQ correction data symbol is delivered to a channel estimator 11, be used to determine channel coefficients, and quilt equilibrium in the impartial device 12 of a channel then, its basis is the channel coefficients that described channel estimator 22 is determined.
Then, the receiving symbol of channel equalization is delivered to a symbol decision-making circuit 13, wherein the data symbol for described equilibrium carries out a symbol determination procedure.Described symbol decision-making circuit 13 has two outputs.After described symbol decision, there is new reference symbol to can be used for all subcarrier n/-n, described reference symbol is exported to first output of described symbol decision unit 13.
Described reference symbol to IQ estimator 14 is provided, and wherein the channel coefficients that is provided based on described reference symbol and described channel estimator 11 carries out the estimation of described IQ distortion parameter.To provide by the IQ distortion parameter that described IQ estimator 14 is reappraised, therefore based on present data block or next data block, the iteration of upgrading to described IQ correcting circuit 10.
The present invention can be used for the receiver notion, wherein is preferably the receiving inputted signal branch between I and the Q[, still is the analog circuit part of described receiver.Most important applications of the present invention is about so-called direct mixing receiver, as paper the 3.5th figure of the Schuchert that quotes in the background of invention.Yet the present invention can be used for the known heterodyne receiver with direct mixing second stage in principle, shown in the 3.6th figure in the above-mentioned related article.This has the modification of heterodyne receiver formula one heterodyne receiver of direct mixing second stage, and wherein said second mix stages is to be embodied as direct hybrid analog-digital simulation quadrature receiver.Also can occur in this receiver in the IQ mistake described in the background of invention, and can be estimated with balanced by the method according to this invention.

Claims (20)

1. one kind is used to estimate the method with the correcting wireless distorted signals, described distortion is formed by emitter terminals homophase and orthogonal branches (IQ) asymmetry and channel distortion, described wireless signal is to launch in a multicarrier launching technique, and it has respectively with respect to a centre frequency f cAnd the subcarrier n and the subcarrier-n of balanced configuration is characterized in that:
A. at first, will be with the described channel coefficients that previous data block was determined according to the received data symbol equilibrium of first data block;
B. then, the described IQ distortion parameter that is determined with a temporary transient process data block is with described data symbol equilibrium;
C., data symbol to the symbol determination procedure of described equilibrium then is provided;
D. reference symbol that described symbol determination procedure is provided and the data symbol that is received are provided for a channel estimating, advance to produce new channel coefficients; And
E. produce described new IQ distortion parameter, its basis is the described new channel coefficients that is determined, described reference symbol and described received data symbol in described channel estimation process.
2. method as claimed in claim 1 is characterized in that
When described method begins, in method step a and b, with the described data symbol equilibrium that is comprised in the data block that begins together, thereby carry out a signal based on pilot signal and estimate, and in step a, utilize by described channel and estimate the channel parameter that determined frequently the data symbol equilibrium that is received, and in method step b, described IQ distortion parameter setting is equalled zero.
3. as the method for claim 1 or 2, it is characterized in that
F. with the described new channel coefficients that determines among method step d and the e and new IQ distortion parameter received data symbol repetition methods step a to e to second data block of described first data block of temporary connection; And
G. described new channel coefficients and the described new IQ distortion parameter that is determined with method step f is with the received data symbol equilibrium of described first several piece.
4. as the method for claim 1 or 2, it is characterized in that
F. with the described new channel coefficients that determines among method step d and the e and new IQ distortion parameter received data symbol repetition methods step a to e for described first data block; And
G. described new channel coefficients that is determined with method step f and described new IQ distortion parameter are with the received data symbol equilibrium of described first several piece.
5. method as claimed in claim 1 is characterized in that
In method step d, produce described new channel coefficients, this is because described channel estimating that the reference symbol that is provided with described symbol determination procedure is the basis to be determined from a channel estimating and received data symbol are the old value weighted averages that is provided in described channel coefficients.
6. method as claimed in claim 1 is characterized in that
In method step e, produce described new IQ distortion parameter, this is that the described IQ distortion parameter that is determined, described reference symbol and described received data symbol are average with the described IQ distortion parameter that is determined in one or more previous iterative step owing to the described new channel coefficients to be determined in the described channel estimation process.
7. method as claimed in claim 1 is characterized in that
Before method step d,, carry out an IQ predistortion (predistortion) of the described reference symbol that described symbol determination procedure provided based on the IQ distortion parameter of described renewal.
8. method as claimed in claim 1 is characterized in that
In method step e, the basis that produces described new IQ distortion parameter is following equation
b ^ n TX = d ^ n ′ ( i ) - C n · d n ( i ) C n · d - n * ( i )
b ^ - n TX = d ^ - n ′ ( i ) - C - n · d - n ( i ) C - n · d n * ( i ) .
9. one kind is used to estimate the method with the correcting wireless distorted signals, described distortion is formed by receiver end homophase and orthogonal branches (IQ) asymmetry and channel distortion, described wireless signal is to launch in a multicarrier launching technique, and it has respectively with respect to a centre frequency f cAnd the subcarrier n and the subcarrier-n of balanced configuration is characterized in that:
A. will be with the described IQ distortion parameter that temporary transient process data block was determined according to the received data symbol equilibrium of first data block;
B. then, the data symbol of described IQ equilibrium is delivered to a channel estimating, advance with the decision channel coefficients;
C. then, with described channel coefficients with described data symbol equilibrium;
D., data symbol to the symbol determination procedure of described channel equalization is provided; And
E. produce described new IQ distortion parameter, its basis is described reference symbol that described symbol determination procedure is provided and by described channel coefficients that described channel estimating provided.
10. method as claimed in claim 9 is characterized in that
F. come received data symbol repetition methods step a to e with the described new IQ distortion parameter that determines among the method step e to second data block of described first data block of temporary connection; And
G. described new channel coefficients that is determined with method step f and described new IQ distortion parameter are with the received data symbol equilibrium of described first several piece.
11. method as claimed in claim 9 is characterized in that
F. with the described new IQ distortion parameter that determines among the method step e received data symbol repetition methods step a to e to described first data block; And
G. described new channel coefficients that is determined with method step f and described new IQ distortion parameter are with the received data symbol equilibrium of described first several piece.
12., it is characterized in that as each method in the claim 9 to 11
In method step e, the basis that produces described new IQ distortion parameter is following equation
b ^ n RX = d ^ n ′ ( i ) - C n · d n ( i ) C - n · d - n * ( i )
b ^ n RX = d ^ - n ′ ( i ) - C - n · d - n ( i ) C n · d n * ( i ) .
13. one kind is directly mixed the method for using aforementioned each claim in the receiver one.
14. one kind has one and to use each method of aforementioned claim 1 to 12 in the heterodyne receiver of direct mixing second stage.
15. a device that is used for arbitrary method of enforcement of rights requirement 1 to 8, it comprises:
The impartial device (2) of one channel is used for the received data symbol of a balanced data block;
One homophase and orthogonal branches (IQ) correcting circuit (3) is used for the described IQ equilibrium of the described data symbol that the impartial device of described channel (2) provided;
One symbol decision unit (4) the described data symbol that is provided by described IQ correcting circuit (3) is provided and carries out a symbol determination procedure;
One channel estimator (6) is used to produce new channel coefficients, and its basis is to determine described reference symbol and the described received data symbol that unit (4) is presented by described symbol;
One IQ tracking cell (7) is used to produce described new IQ distortion parameter, and its basis is described new channel coefficients, described reference symbol and the described received data symbol that described channel estimator (6) is provided; And
The output of described IQ tracking cell (7), it is an input that is connected to described IQ correcting circuit (3).
16. the device as claim 15 is characterized in that
One IQ predistortion (predistortion) unit (5), the IQ distortion parameter that is used for described renewal serves as that an IQ predistortion is carried out in the basis on the described reference symbol that described symbol determines unit (4) to be provided; And
Described IQ pre-distortion unit (5) is to have one first input, it is connected to the described output of described symbol decision unit (4), and one second input, and it is connected to an output of described IQ tracking cell (7), and one output, it is connected to described channel estimator (6).
17. the device as claim 15 or 16 is characterized in that
One averaging unit (8), be used to carry out the average of described IQ distortion parameter, determine the basis of described IQ distortion parameter to be described new channel coefficients, described reference symbol that in described channel estimation process, determines and received data symbol with the described IQ distortion parameter that in one or more previous iterative step, determines; And
One input of described averaging unit (8) is an output that is connected to described IQ tracking cell (7), and an output of described averaging unit (8) is to be connected to an input of described IQ correcting circuit (3) and an input of described IQ pre-distortion unit (5).
18., it is characterized in that as each device in the claim 13 to 15
One channel estimator (1), described received data symbol can be fed to its input, and then provide the described channel coefficients that is determined by described channel estimating in its output.
19. the device as claim 18 is characterized in that
One change over switch (changeover switch), the described input of the impartial device of described by this channel (2) is the described output that is connected to the described input of described channel estimator (1) or is connected to described channel estimator (6).
20. one kind is used for the device that enforcement of rights requires 9 to 12 each methods, it comprises:
One homophase and orthogonal branches (IQ) correcting circuit (10) is used for the IQ equilibrium of described received data symbol;
One channel estimator (11) is used to produce channel coefficients and it is the described output that is connected to described IQ correcting circuit (10);
The impartial device (12) of one channel is used for balanced described received data symbol, its basis described channel coefficients for being provided by described channel estimator (11);
One symbol decision unit (13) is used for carrying out a symbol determination procedure by the described data symbol that the impartial device of described channel (12) is provided; And
One IQ estimator (14), be used to produce the IQ distortion parameter, described channel coefficients, described reference symbol and described received data symbol that its basis is provided for the described reference symbol that provided by described symbol decision-making circuit (13), by described channel estimator (11); One output of described IQ estimator (14) is an input that is connected to described IQ correcting circuit (10).
CN 03821378 2002-09-09 2003-08-26 Iterative estimation and equalization of asymmetries between inphase and quadrature branches in multicarrier transmission systems Pending CN1682508A (en)

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DE2002141679 DE10241679A1 (en) 2002-09-09 2002-09-09 IQ-asymmetries iterative estimation and correction method e.g. for multi-carrier transmission systems, requires using new channel coefficients together with reference symbols

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CN102130865A (en) * 2010-01-13 2011-07-20 英飞凌科技股份有限公司 Radio receiver and method for channel estimation

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FR2878393B1 (en) 2004-11-23 2007-01-12 Commissariat Energie Atomique METHOD AND DEVICE FOR COMPENSATING FOR IMBALANCES OF A RECEIVER

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US6009317A (en) * 1997-01-17 1999-12-28 Ericsson Inc. Method and apparatus for compensating for imbalances between quadrature signals
US6442217B1 (en) * 2000-05-22 2002-08-27 Sicom, Inc. Digital communication receiver with digital, IF, I-Q balancer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102130865A (en) * 2010-01-13 2011-07-20 英飞凌科技股份有限公司 Radio receiver and method for channel estimation
CN102130865B (en) * 2010-01-13 2015-02-11 英特尔移动通信有限责任公司 Radio receiver and method for channel estimation

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