CN100384269C - System and method for compensating nonideal characteristics of transmitter in base station - Google Patents

Abstract

The present invention provides a system and a method for compensating the non-ideal characteristics of a transmitter of a base station. The present invention is characterized in that a signal feedback path and a DSP module are added to the existing base station system based on an AQM technology; IQ signals are collected from base bands by the DSP module to calculate the non-ideal characteristic parameters of the whole transmitter of the base station; the non-ideal characteristic parameters of the whole transmitter of the base station are sent to a QMC network module; the calculated non-ideal characteristic parameters are subtracted from the current parameters by the QMC network module; the obtained updated parameters are used for compensating the IQ signals from the base bands; then, the compensated IQ signals are sent to a transmitting path. The steps are repeated and iterated and the QMC network module is used for precorrecting the IQ signals from the base bands so as to compensate the non-ideal characteristics of the whole transmitter of the base station and guarantee the performance of the signal transmission of the base station on the premise of low cost for the base station.

Description

A kind of system and method that compensates base station sender non-ideal characteristic

Technical field

The present invention relates to the base station system technical field of structures in the 3-G (Generation Three mobile communication system), be meant a kind of system and method that compensates base station sender non-ideal characteristic especially.

Background technology

In 3-G (Generation Three mobile communication system), the cost of base station mainly concentrates on the transceiver of intermediate frequency and radio frequency.Reduce the transceiver cost and become the problem that each equipment manufacturers must pay close attention to.Traditional sender based on the software radio system structure adopts the double conversion scheme.That is, at first will be modulated to digital intermediate frequency by the IQ signal that I (In-phase) signal and Q (Quadrature) signal constitute at numeric field; Adopt digital-to-analogue conversion (DAC) device at a high speed that signal is carried out digital-to-analogue conversion then, obtain analog if signal; Adopt the RF spot that frequency converter up-converts the signals to be needed at last, this method is also referred to as digital quadrature modulation (DQM).

Adopt the base station of DQM technology, must adopt high accuracy DAC device relatively at a high speed to carry out digital-to-analogue conversion, and this class DAC device costs an arm and a leg; Simultaneously, on the radio-frequency channel, in order to suppress to produce in the up-conversion process mirror image problem of signal, need to adopt band pass filter to suppress by one in two image signals of frequency converter generation, and because the restriction of DAC device performance, the intermediate-freuqncy signal frequency can not be too high, and this makes to the requirement of band pass filter very harsh, similarly, the price of this filter also is expensive; Simultaneously, because there are local frequencies such as intermediate frequency, up-conversion in the existence of intermediate-freuqncy signal in transceiver, this will make the spurious signal of system be difficult to handle, and increase the complexity of system design.

For solving the problems referred to above that the DQM technology is brought, analog quadrature modulation (AQM) technology can be adopted in the base station at present.So-called AQM technology is meant directly passes through the AQM device with the analog I signal, is modulated to the method for radio frequency, and wherein, the AQM device is also referred to as the IQ modulator.

Figure 1 shows that the base station sender structure chart of the employing AQM technology of prior art.After digital quadrature compensation (QMC) mixed-media network modules mixed-media 120 receives I signal and Q signal from baseband modem (Modem) module 110, after using in the QMC mixed-media network modules mixed-media self current parameter the non-ideal characteristic of whole base station sender IQ signal being compensated processing, IQ signal after the compensation is sent into transmission channel 130, DAC module 131a and DAC module 131b by transmission channel 130 interior two relative low speed, convert digital I signal and digital Q signal to Simulation with I signal and simulation Q signal respectively, this analog I signal is respectively by behind low pass filter blocks 132a and the low pass filter blocks 132b, enter AQM device 133, radio-frequency (RF) local oscillator module 134 provides local oscillation signal for AQM device 133, the frequency of local oscillation signal is desired rf frequency, and the analog signal that is modulated to radio frequency can send by power amplifier module 140 and antenna.

Because the I signal in the IQ signal and the bandwidth on each road of Q signal all are the modulation signal bandwidth half, according to nyquist sampling theorem, directly the IQ signal being transformed to analog signal respectively also only needs half bandwidth of modulation signal.Because the digital-to-analogue rate of change is lower, can adopt relatively cheap DAC device, though used two DAC, total cost has still reduced.In addition, radio frequency part need not filtering, and spurious signal is handled easily, and system design is simple.Therefore, the AQM scheme is low, a design realization simple proposal of cost.

But also there is following defective in such scheme: because the AQM device is an analogue device, in the process of carrying out analog-modulated, the AQM Devices Characteristics can cause the reduction of modulation signal quality.See on the whole, show as the IQ distorted signals that the base station sends, thereby make the base station sender show the non-ideal characteristic of following three aspects:

1) gain is uneven.So-called gain imbalance is meant I different with the gain of Q two paths of signals.

2) unbalance in phase claims quadrature error again.So-called unbalance in phase be meant with the modulation of IQ two paths of signals in its phase place of quadrature carrier be not that strictness differs 90 °, have certain error.

3) direct current biasing.So-called direct current biasing is meant on the IQ signal that direct current signal is added to original.

Gain is uneven will to cause that with unbalance in phase the relative local oscillation signal of spectrum of radio frequency signals produces mirror image, and direct current biasing will cause the leakage of radiofrequency signal local oscillator, and they all can worsen signal quality, increase the error rate of receiving terminal.If it is gain imbalance, unbalance in phase and direct current biasing error are static, just passable through simple correction so.But the non-ideal characteristic of whole base station sender is along with the variation of external conditions such as temperature, signal power changes.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of system and method that compensates base station sender non-ideal characteristic, guaranteeing that the base station cheaply under the prerequisite, realizes the compensation to base station sender non-ideal characteristic.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of system that compensates base station sender non-ideal characteristic, at least comprise base band modem module 210, QMC mixed-media network modules mixed-media 220 and comprise analog quadrature modulation (AQM) device transmission channel 230, this system further comprises: signal feedback passage 240 and digital signal processor DSP module 250, wherein

Described QMC mixed-media network modules mixed-media 220, reception is from the I signal and the Q signal of base band modem module 210, and from the result of calculation signal of digital signal processor DSP module 250, carry out real-time treatment for correcting to the received signal after, give transmission channel 230 with the IQ signal after handling;

Described signal feedback passage 240, the radiofrequency signal of transmission channel 230 is come from collection, and after the radiofrequency signal that collects is transformed to intermediate-freuqncy signal, this intermediate-freuqncy signal carried out analog-to-digital conversion obtain feeding back the IQ signal, should feed back the IQ signal then and send DSP module 250 to;

Described digital signal processor DSP module 250, collection is from the I signal and the Q signal of base band modem module 210, and from the feedback sample digital signal of feedback path 240, obtain the feedback signal of one group of above different delayed time, calculate the mean square error between each group delay of feedback signal and the baseband signal respectively, the delay value of the pairing one group of delay of feedback signal of mean square error minimum value that calculates as the delay value D between base band and the feedback signal, and then is obtained by the time delay filter in the DSP and to calculate required baseband I Q signal and feedback IQ signal; And utilize the transmission characteristic of QMC mixed-media network modules mixed-media and AQM device integral body, the method for using ORTHOGONAL TRIANGULAR DECOMPOSITION is calculated the non-ideal characteristic parameter of whole base station sender, and sends result of calculation to QMC mixed-media network modules mixed-media 220.

Preferably, at least comprise coupler 241, down conversion module 242 and analog-to-digital conversion module 243 in the described signal feedback passage 240, wherein, coupler 241 is gathered the radiofrequency signal that comes from transmission channel 230, and send the radiofrequency signal that collects to down conversion module 242, after by down conversion module 242 this conversion of signals being intermediate frequency, send analog-to-digital conversion module 243 to, will be sent to DSP module 250 through the digital signal that analog-to-digital conversion process obtains.

Preferably, described down conversion module 242 is frequency mixer or analog quadrature demodulator.

Preferably, described QMC mixed-media network modules mixed-media 220 is an on-site programmable gate array FPGA, or special integrated chip ASIC.

A kind of application is the method for system as mentioned above, and this method may further comprise the steps:

A, initialization system;

B, DSP gather baseband I Q signal and feedback IQ signal, obtain the feedback signal of one group of above different delayed time, calculate the mean square error between each group delay of feedback signal and the baseband signal respectively, the delay value of the pairing one group of delay of feedback signal of mean square error minimum value that calculates as the delay value D between base band and the feedback signal, and then is obtained by the time delay filter in the DSP and to calculate required baseband I Q signal and feedback IQ signal; Use required baseband I Q signal of described calculating and feedback IQ signal then, utilize the transmission characteristic of QMC network and AQM device integral body, and the method for ORTHOGONAL TRIANGULAR DECOMPOSITION is calculated the non-ideal characteristic parameter of whole base station sender;

C, according to the described non-ideal characteristic parameter of step b whether in predefined scope, judge whether this non-ideal characteristic parameter is reasonable, if, then upgrade the current parameter of QMC mixed-media network modules mixed-media, use updated parameters the IQ signal is compensated processing, and after will sending through the IQ signal after the compensation deals, repeated execution of steps b again, otherwise direct repeated execution of steps b.

Preferably, the described method that the signal of being gathered is carried out the time unifying computing of step b is: at first, DSP obtains the feedback signal of one group of above different delayed time, and calculate mean square error between each group delay of feedback signal and baseband signal respectively, the delay value of the pairing one group of delay of feedback signal of mean square error minimum value that calculates as the delay value D between base band and the feedback signal, and then is obtained by the time delay filter in the DSP and to calculate required IQ signal and feedback IQ signal.

Preferably, the time delay filter in the described DSP is the sinc filter, or the FIR filter, or iir filter, or transfer function is H (z)=(1-α)+α z ^-1The filter of form.

Preferably, the method of the non-ideal characteristic parameter of the described whole base station of step b sender is: DSP uses IQ signal and the feedback IQ signal that collects, utilize the transmission characteristic of QMC network and AQM device system integral body, the method for using ORTHOGONAL TRIANGULAR DECOMPOSITION is calculated the non-ideal characteristic parameter of whole base station sender.

Preferably, the described predefined scope of step c is provided with according to system configuration.

Preferably, the method for the described renewal of step c QMC mixed-media network modules mixed-media parameter current is: the QMC mixed-media network modules mixed-media is used the non-ideal characteristic parameter that current self parameter deducts the described whole base station of step b sender.

Preferably, when direct current biasing, gain imbalance and unbalance in phase appearred in the initial stage, this method further comprised: at first upgrade the value of direct current biasing, and after the value of direct current biasing restrains substantially, the value of the uneven and unbalance in phase of new gain more again.

Preferably, this method further comprises: adopt training signal that the non-ideal characteristic of whole base station sender is surveyed, and obtain initial value, when system initialization, directly in the QMC network, load acquired initial value, and then carry out subsequent step by DSP.

Preferably, described training signal is a pseudo-random signal.

The present invention is in existing base station system based on the AQM technology, increase a signal feedback passage and DSP module, gather the IQ signal by the DSP module from base band, from feedback path, gather radiofrequency signal through conversion, promptly feed back the IQ signal, and after using the non-ideal characteristic parameter of the whole base station of the calculated signals sender that is collected, the non-ideal characteristic parameter of this whole base station sender is sent into the QMC mixed-media network modules mixed-media, after from current parameter, deducting the non-ideal characteristic parameter that calculates by the QMC mixed-media network modules mixed-media, the undated parameter compensation that application obtains will be somebody's turn to do then through the IQ of overcompensation signal and send into transmission channel from the IQ signal of base band.So iterate, can enough be approached actual QMC parameter.The present invention uses the QMC mixed-media network modules mixed-media IQ signal from base band is carried out precorrection before the baseband I Q signal carries out digital-to-analogue conversion, thereby guarantees in the base station cheaply to have realized the compensation to the non-ideal characteristic of whole base station sender under the prerequisite.

Use the present invention, have the following advantages:

1) adopt technology of the present invention, the variation that the QMC mixed-media network modules mixed-media can be followed the tracks of adaptively, proofread and correct the non-ideal characteristic of base station system, and not in time, the variation of external condition such as temperature, carrier frequency point, device aging and changing;

2) under the situation that satisfies WCDMA, cdma2000 and IS95 protocol requirement fully, adopt the technology of the present invention can be in baseband digital signal variable power operate as normal under the dynamic range of 30dBc at least;

When 3) the present invention proofreaies and correct signal, to the not influence of power of signal;

4) algorithm of the present invention is insensitive to the influence of quantizing noise, and is less demanding to the quantified precision of feedback signal ADC;

5) use the present invention, need not professional's manual adjustment in the production process, can realize the production automation; Because technology of the present invention can autotracking unit spare characteristic variations, thereby has reduced the operation maintenance cost of base station effectively, has prolonged the base station life-span simultaneously;

6) if at first obtain QMC network parameter coefficient in production phase, when using at the scene directly by DSP loading data in the QMC network, obtaining initial value preferably, and then progressively self adaptation obtains optimal result, can make the calibration result requirement that touches the mark fast like this.

Description of drawings

Figure 1 shows that the base station transmitter system structure chart of the employing AQM technology of prior art;

Figure 2 shows that the base station transmitter system structure chart of using employing AQM technology of the present invention;

Figure 3 shows that the flow chart of using the whole base station of compensation of the present invention sender non-ideal characteristic;

Figure 4 shows that the Mathematical Modeling of the AQM device and the QMC network of prior art.

Embodiment

For making technical scheme of the present invention clearer, the present invention is done detailed description further again below in conjunction with accompanying drawing.

Thinking of the present invention is: in existing base station system based on the AQM technology, increase a signal feedback passage and DSP module, gather the IQ signal by the DSP module from base band, from feedback path, gather radiofrequency signal through conversion, promptly feed back the IQ signal, and after using the non-ideal characteristic parameter of the whole base station of the calculated signals sender that is collected, the non-ideal characteristic parameter of this whole base station sender is sent into the QMC mixed-media network modules mixed-media, after from current parameter, deducting the non-ideal characteristic parameter that calculates by the QMC mixed-media network modules mixed-media, the undated parameter compensation that application obtains will be somebody's turn to do then through the IQ of overcompensation signal and send into transmission channel from the IQ signal of base band.So iterate, can enough be approached actual QMC parameter.The present invention uses the QMC mixed-media network modules mixed-media IQ signal from base band is carried out precorrection before the baseband I Q signal carries out digital-to-analogue conversion, thereby guarantees in the base station cheaply to have realized the compensation to the non-ideal characteristic of whole base station sender under the prerequisite.

Figure 2 shows that the base station transmitter system structure chart of using employing AQM technology of the present invention.QMC mixed-media network modules mixed-media 220, reception is from the I signal and the Q signal of base band modem module 210, result of calculation signal from digital signal processor (DSP) module 250, after carrying out real-time treatment for correcting to the received signal, give transmission channel 230 with the signal after handling, DAC module 231a and DAC module 231b by transmission channel 230 interior two relative low speed, convert digital I signal and digital Q signal to Simulation with I signal and simulation Q signal respectively, this analog I signal is respectively by behind low pass filter blocks 232a and the low pass filter blocks 232b, enter AQM device 233, under the control of radio-frequency (RF) local oscillator module 234, the local frequency of AQM device 233 output signals is desired rf frequency, and this radiofrequency signal can send by power amplifier module 260 and antenna.The process of above-mentioned real-time treatment for correcting is: after deducting the non-ideal characteristic parameter that calculates by the QMC mixed-media network modules mixed-media from current parameter, the undated parameter compensation that application obtains is from the IQ signal of base band.

Simultaneously, sub-fraction signal entering signal feedback path 240 in the radiofrequency signal, be that the sub-fraction radiofrequency signal enters in the down conversion module 242 by coupler 241, after by down conversion module 242 this conversion of signals being intermediate frequency, send analog-to-digital conversion module 243 to, after analog-to-digital conversion process, this digital signal enters DSP module 250.DSP module 250 then collection from the I signal and the Q signal of base band modem module 210, and from the feedback sample digital signal of feedback path 240, and use the signal that is collected the AQM device is carried out the non-ideal characteristic calculation of parameter, and send result of calculation to QMC mixed-media network modules mixed-media 220, finish parameter update by QMC mixed-media network modules mixed-media 220, make the QMC network parameter can follow the tracks of the variation of AQM device property and change.For the approaching as far as possible signal of launching the communication radio frequency end of the sampled digital signal that makes DSP obtain, require feedback path to have favorable linearity and alap noise characteristic, for reaching this purpose, preferably adopt radome that transmission channel and feedback path are separated.

Above-mentioned QMC mixed-media network modules mixed-media 220 is field programmable gate array (FPGA), or special integrated chip (ASIC), and above-mentioned down conversion module 242 is frequency mixer or analog quadrature demodulator.

Figure 3 shows that the flow chart of using the whole base station of compensation of the present invention sender non-ideal characteristic.

Step 301, after system powered on, DSP module and QMC mixed-media network modules mixed-media carried out initialization;

Step 302, the DSP module is gathered the IQ signal of base band and the radiofrequency signal in the transmission channel, after frequency conversion and analog-to-digital conversion process,, IQ signal and the feedback IQ signal gathered are alignd in time the radiofrequency signal of being gathered by self filter as feedback IQ signal; This filter is the sinc filter, or the FIR filter, or iir filter, or transfer function is H (z)=(1-α)+α z ^-1The filter of form;

Step 303, DSP uses the non-ideal characteristic parameter of the whole base station of the calculated signals sender of being gathered;

Step 304, judge whether the non-ideal characteristic parameter that calculates is positioned at the preset parameters scope, if, this non-ideal characteristic Rational Parameters that calculates then, and after the non-ideal characteristic parameter that this calculates sent into the QMC mixed-media network modules mixed-media, execution in step 305, otherwise, the non-ideal characteristic parameter that this calculates is unreasonable, re-executes step 302, till the Rational Parameters that calculates; The preset parameters scope is that the configuration according to base station system decides;

Step 305, QMC mixed-media network modules mixed-media deduct non-ideal characteristic parameter from DSP from self current parameter after, use the undated parameter compensation that the obtains IQ signal from base band, after will sending through the IQ signal of compensation deals, repeated execution of steps 302 again.

In the self-adaptive initial stage,, can influence the result of calculation of gain imbalance and unbalance in phase owing to the existence of local oscillator leakage signals.In order to obtain than great dynamic range, in initial adaptive process, at first upgrade the value of direct current biasing, after the value of direct current biasing restrains substantially, the adaptive updates of begin again to proceed to gain uneven and unbalance in phase.

In addition, in order to improve algorithm the convergence speed, can adopt special training signal, as pseudo-random signal, earlier the non-ideal characteristic of whole base station sender is surveyed, obtaining good initial value, directly in the QMC network, load initial value when using at the scene, and then progressively self adaptation obtains optimal result to obtain by DSP.Can make the calibration result requirement that touches the mark fast like this.

In the present embodiment, suppose that the filter in the DSP is the sinc filter, the method of domain search is calculated the time delay between baseband signal and the feedback signal when specifying the DSP employing below, thus the implementation method that IQ signal that assurance is gathered and feedback digital signal are alignd in time:

Because the signal s (k-D) after certain signal s (k) time-delay D can adopt following formula to represent:

$s(k-D)=\underset{n=-\∞}{\overset{\∞}{\mathrm{\Σ}}}\sin c(n-D)s(k-n)---\left(1\right)$

$\sin c\left(x\right)=\frac{\sin \left(\mathrm{\πx}\right)}{\mathrm{\πx}}---\left(2\right)$

In the following formula, k represents the label of signal sampling point, and n then is the intermediate variable of convolutional filtering, and formula (2) shows the formula that embodies of sinc function in the formula (1).

The computational methods of delay value are: in the possible delay value scope of system design, feedback signal is carried out the filtering wave by prolonging time operation, to obtain the feedback signal of different delayed time more than a group, calculate the mean square error between each group delay of feedback signal and the baseband signal then respectively, and the square mean error amount of therefrom taking-up minimum, the delay value of one group of delay of feedback signal of this minimum value correspondence is exactly the delay value D between base band and the feedback signal, last again by the time delay filter in the DSP, obtain and calculate required IQ signal and feedback IQ signal, be the time unifying that through type (1) can be realized baseband signal and feedback signal, obtain calculating required base band and feedback IQ signal.

Specify DSP below according to the signal of gathering, calculate the method for the non-ideal characteristic parameter of whole base station sender.

Referring to Fig. 4, Figure 4 shows that the Mathematical Modeling of the AQM device and the QMC mixed-media network modules mixed-media of prior art.In order to compensate the non-ideal characteristic of whole base station sender, the Mathematical Modeling structural similarity reversed in order of the Mathematical Modeling of QMC network and AQM device.Subscript c among the figure represents the signal in the QMC network model, and subscript p represents the signal in the AQM device model.α _C1, α _C2, φ _c, b _C1, b _C2The value of representing the direct current biasing on gain, unbalance in phase value, I road and the Q road on I road and Q road signal in the QMC network respectively.I _d, Q _dThe output IQ complex signal of expression Baseband Modem, I _c, Q _cExpression QMC network outputs to the plural IQ signal of DAC.

Because the error between real AQM device and the desirable device is small, therefore can adopt the method for first approximation to obtain the transmission characteristic of QMC network and AQM device system integral body, specific as follows:

$\left(\begin{array}{c}{I}_q\\ Q_q\end{array}\right)=\left(\begin{array}{cc}1+\frac{{\mathrm{\&epsiv;}}_c+{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">p</figure-callout>}}}{2}& \frac{\mathrm{\&phi;}}{2}\\ \frac{\mathrm{\&phi;}}{2}& 1-\frac{{\mathrm{\&epsiv;}}_c+{\mathrm{\&epsiv;}}_p}{2}\end{array}\right)\left(\begin{array}{c}{I}_d\\ Q_d\end{array}\right)+\left(\begin{array}{c}{b}_{c1}\\ {\mathrm{<figure-callout\; id="2"\; label="b\; c"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">b</figure-callout>}}_c\end{array}\right)+\left(\begin{array}{c}{b}_{p1}\\ b_{p2}\end{array}\right)---\left(3\right)$

I wherein _d, Q _dThe output IQ complex signal of expression Baseband Modem.ε in the following formula _c, ε _pSubstitute α _C1, α _C2, α _P1, α _P2The gain imbalance of expression QMC network and AQM device, the relation between the two is:

${\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">p</figure-callout>}1}=1+\frac{{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">p</figure-callout>}}}{2}$ ${\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">c</figure-callout>}1}=1+\frac{{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">c</figure-callout>}}}{2}$

${\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">p</figure-callout>}2}=1-\frac{{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">p</figure-callout>}}}{2},$ ${\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">c</figure-callout>}2}=1-\frac{{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="C20041000602000172.png"\; state="\{\{state\}\}">c</figure-callout>}}}{2}$

The non-ideal characteristic of AQM device is expressed as q _p=(ε _pφ _pb _P1b _P2) ^T, be q with the non-ideal characteristic parametric representation of QMC network _c=(ε _cφ _cb _C1b _C2) ^T, then can be easy to obtain the non-ideal characteristic q of whole system by (3) formula _Total=(ε φ b ₁b ₂) be:

q _total≈q _c+q _p。(4)

As seen, the non-ideal characteristic of whole base station sender can be expressed as adding up of QMC mixed-media network modules mixed-media and AQM device two parts non-ideal characteristic.If the non-ideal characteristic parameter of QMC mixed-media network modules mixed-media and AQM device is opposite number each other, then whole base station system system will show as idealized system.

In the present embodiment, utilize above-mentioned principle, adopt the method directly find the solution baseband signal and feedback IQ signal equation to calculate the value of the non-ideal characteristic of whole base station system system.Concrete steps are as follows:

At first, the DSP module is obtained IQ signal and feedback IQ signal.Because the feedback path signal is identical with the emitting radio frequency signal characteristic, therefore,, obtain the non-ideal characteristic of whole base station system system by finding the solution the equation that constitutes by baseband I Q signal and feedback IQ signal, concrete process is as follows:

According to formula (3), wherein vector form to be launched, the relation between the base band and feedback signal I, Q that can obtain after the normalization is as follows:

I(1+ε/2)+Q(φ/2)+b ₁＝i

I(φ/2)+Q(1-ε/2)+b ₂＝q (5)

Wherein I, Q represent the I signal and the Q signal of baseband signal respectively, and i, q be I signal of expression feedback respectively and Q signal then, ε, φ, b ₁, b ₂Be respectively q in the formula (3) _TotalFour components.

Secondly, formula (5) is converted to redundant equation group of following quaternary, this equation group is as follows with matrix notation:

$\left(\begin{array}{cccc}\&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;\\ I_k/2& Q_k/2& 1& 0\\ -Q_k/2& I_k/2& 0& 1\\ \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;\end{array}\right)\left(\begin{array}{c}\mathrm{\&epsiv;}\\ \mathrm{\&phi;}\\ b_1\\ b_2\end{array}\right)=\left(\begin{array}{c}\&CenterDot;\&CenterDot;\&CenterDot;\\ i_k-I_k\\ q_k-Q_k\\ \&CenterDot;\&CenterDot;\&CenterDot;\end{array}\right)$

K represents k sampling point collecting in the formula, total N of such sampling point, I _k, Q _k, i _k, q _kI and the Q component of representing the base band and the feedback signal of k sampling point correspondence respectively.So the dimension of coefficient matrix is 2N * 4 in the equation, at this, this matrix is designated as A, the vector on equation the right is designated as B.Above-mentioned matrix A is carried out ORTHOGONAL TRIANGULAR DECOMPOSITION (QR decomposition), obtain

A＝QR

Wherein, R represents a upper triangular matrix, and the Q matrix is (2N) * (2N) orthogonal dimension matrix, satisfies Q ^TQ=I, T representing matrix transposition, I representation unit matrix; Like this, can obtain q _TotalThe computing formula of least square solution is

q _total＝Q ^TR ^-1B (6)

Application formula (6) can be obtained the value of the non-ideal characteristic parameter of whole base station sender.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (11)

1. system that compensates base station sender non-ideal characteristic, at least comprise base band modem module (210), QMC mixed-media network modules mixed-media (220) and comprise the transmission channel (230) of analog quadrature modulation AQM device, it is characterized in that, this system further comprises: signal feedback passage (240) and digital signal processor DSP module (250), wherein

Described QMC mixed-media network modules mixed-media (220), reception is from the I signal and the Q signal of base band modem module (210), and from the result of calculation signal of digital signal processor DSP module (250), after carrying out real-time treatment for correcting to the received signal, give transmission channel (230) with the IQ signal after handling;

Described signal feedback passage (240), the radiofrequency signal of transmission channel (230) is come from collection, and after the radiofrequency signal that collects is transformed to intermediate-freuqncy signal, this intermediate-freuqncy signal carried out analog-to-digital conversion obtain feeding back the IQ signal, should feed back the IQ signal then and send DSP module (250) to;

Described digital signal processor DSP module (250), collection is from the I signal and the Q signal of base band modem module (210), and from the feedback sample digital signal of feedback path (240), obtain the feedback signal of one group of above different delayed time, calculate the mean square error between each group delay of feedback signal and the baseband signal respectively, the delay value of the pairing one group of delay of feedback signal of mean square error minimum value that calculates as the delay value D between base band and the feedback signal, and then is obtained by the time delay filter in the DSP and to calculate required baseband I Q signal and feedback IQ signal; And utilize the transmission characteristic of QMC mixed-media network modules mixed-media and AQM device integral body, the method for using ORTHOGONAL TRIANGULAR DECOMPOSITION is calculated the non-ideal characteristic parameter of whole base station sender, and sends result of calculation to QMC mixed-media network modules mixed-media (220).

2. system according to claim 1, it is characterized in that, at least comprise coupler (241), down conversion module (242) and analog-to-digital conversion module (243) in the described signal feedback passage (240), wherein, coupler (241) collection is come from the radiofrequency signal of transmission channel (230), and send the radiofrequency signal that collects to down conversion module (242), after by down conversion module (242) this conversion of signals being intermediate frequency, send analog-to-digital conversion module (243) to, will be sent to DSP module (250) through the digital signal that analog-to-digital conversion process obtains.

3. system according to claim 2 is characterized in that, described down conversion module (242) is frequency mixer or analog quadrature demodulator.

4. system according to claim 1 is characterized in that, described QMC mixed-media network modules mixed-media (220) is an on-site programmable gate array FPGA, or special integrated chip ASIC.

5. use the method for system according to claim 1 for one kind, it is characterized in that this method may further comprise the steps:

A, initialization system;

B, DSP gather baseband I Q signal and feedback IQ signal, obtain the feedback signal of one group of above different delayed time, calculate the mean square error between each group delay of feedback signal and the baseband signal respectively, the delay value of the pairing one group of delay of feedback signal of mean square error minimum value that calculates as the delay value D between base band and the feedback signal, and then is obtained by the time delay filter in the DSP and to calculate required baseband I Q signal and feedback IQ signal; Then, use required baseband I Q signal of described calculating and feedback IQ signal, utilize the transmission characteristic of QMC network and AQM device integral body, and the method for ORTHOGONAL TRIANGULAR DECOMPOSITION is calculated the non-ideal characteristic parameter of whole base station sender;

C, according to the described non-ideal characteristic parameter of step b whether in predefined scope, judge whether this non-ideal characteristic parameter is reasonable, if, then upgrade the current parameter of QMC mixed-media network modules mixed-media, use updated parameters the IQ signal is compensated processing, and after will sending through the IQ signal after the compensation deals, repeated execution of steps b again, otherwise direct repeated execution of steps b.

6. method according to claim 5 is characterized in that, the time delay filter in the described DSP is the sinc filter, or the FIR filter, or iir filter, or transfer function is H (z)=(1-α)+α z ^-1The filter of form.

7. method according to claim 5 is characterized in that, the described predefined scope of step c is provided with according to system configuration.

8. method according to claim 5 is characterized in that, the method for the described renewal of step c QMC mixed-media network modules mixed-media parameter current is: the QMC mixed-media network modules mixed-media is used the non-ideal characteristic parameter that current self parameter deducts the described whole base station of step b sender.

9. method according to claim 5, it is characterized in that, when direct current biasing, gain imbalance and unbalance in phase appear in the initial stage, this method further comprises: the value of at first upgrading direct current biasing, after the value of direct current biasing restrains substantially, the value of the uneven and unbalance in phase of new gain more again.

10. method according to claim 5, it is characterized in that, this method further comprises: adopt training signal that the non-ideal characteristic of whole base station sender is surveyed, and acquisition initial value, when system initialization, directly in the QMC network, load acquired initial value, and then carry out subsequent step by DSP.

11. method according to claim 10 is characterized in that, described training signal is a pseudo-random signal.

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