CN100428651C - Down wave beam shaping method and device of radio channel - Google Patents

Abstract

The present invention provides a down traveling wave beam forming method and a device for a wireless channel. The method comprises the following steps: carrying out channel estimation for the antennas; carrying out parameter estimation for user space according to the channel estimation of the antennas; carrying out wave beam forming weight vector estimation according to the space parameter estimation; controlling wave beam forming according to the wave beam forming weight vector estimation. The device comprises a plurality of channel receiving estimation devices and channel transmitting estimation devices, a correlated device, a correlated channel parameter estimation device and a wave beam forming device, wherein the channel receiving estimation devices and the channel transmitting estimation devices are used for the output of much channel receiving estimation and channel transmitting estimation, the relevant device is used for the correlation of the channel receiving estimation and the channel transmitting estimation, the correlated channel parameter estimation device is used for obtaining channel parameter estimation according to correlated results, and the wave beam forming device is used for the forming of wave beams according to the channel parameter estimation. With the present invention, the wave beam forming of an antenna can be determined according to the characteristics of an environment.

Description

The down beam shaping method of wireless channel and device

Technical field

The present invention relates to mobile communication, relate in particular to the down beam shaping method and the device of wireless channel.

Background technology

In mobile communication system, the research of intelligent antenna technology and application have been subjected to attention more and more widely.Smart antenna using digital signal, produce the spatial orientation wave beam, make antenna main beam aim at the subscriber signal arrival direction, secondary lobe or zero falls into aims at the interference signal arrival direction, to reach the purpose of fully efficiently utilizing mobile subscriber's signal and suppressing interference signal.Utilize smart antenna can make useful signal maximization and interference signal minimizes, thus greatly improved system capacity, enlarged the covering of system.The application of smart antenna in cellular mobile communication mainly contains the technology aspect two: one is many antennas reception treatment technologies of upward signal, and another is the wave beam forming transmission technology of downstream signal.The up reception of smart antenna is that many antenna receiving signals are directly handled, and down beam shaping is to utilize the feedback of up received signal or downstream station received signal to determine indirectly that base station down sends the figuration parameter of signal.Therefore, the realization of smart antenna downlink wave bundle shaping scheme depends on the constant or gradual property of time of mobile channel environmental characteristics parameter.

For the terminal far away from the base station, the angular spread of its signal space propagation is less usually, the main direction that has tangible signal wave to reach, and direction of arrival is a gradual amount (with respect to the frame period) in time.In this case, common intelligent antenna figuration algorithm can be realized down beam shaping effectively reliably.

For terminal nearer from the base station and that the signal communication environments is comparatively complicated, the angular spread that its signal space is propagated is bigger, the main direction that does not have tangible signal wave to reach, and direction of arrival is a fast variable (with respect to the frame period) in time.In this case, common intelligent antenna figuration algorithm can not be realized down beam shaping effectively reliably, even figuration occurs not as the situation of figuration not.

Because the complicated time-varying characteristics of mobile telecommunication channel wish to have a kind of down beam shaping method of smart antenna and device to decide figuration according to the characteristic of environment.

Summary of the invention

The objective of the invention is shortcoming, a kind of down beam shaping method and device of wireless channel is provided, be used to have the system of a plurality of antennas and R-T unit at above-mentioned prior art.

Method of the present invention comprises step:

A kind of down beam shaping method of wireless channel is used to have the system of a plurality of antennas and R-T unit, it is characterized in that described method comprises step:

Described a plurality of antennas are carried out channel estimating;

According to the channel estimating of described a plurality of antennas, carry out the user's space parameter Estimation;

According to described spatial parameter estimation, carry out the wave beam forming weight vector and estimate, from least two kinds of shaped-beam parameters, obtain a kind of shaped-beam parameter;

Estimate the control wave beam forming according to the wave beam forming weight vector.

Preferable, the described user's space parameter Estimation of carrying out comprises step:

Carry out the user's space correlation matrix estimation;

According to described channel estimating and correlation matrix estimation, carry out the spatial power directional spectrum and estimate;

Estimate according to described spatial power directional spectrum, carry out the space time characterisitic parameter and estimate.

Described spatial parameter estimation comprises: the spatial power directional spectrum is estimated and the space time characterisitic parameter is estimated.

Preferable, describedly from least two kinds of shaped-beams, obtain a kind of shaped-beam and comprise: from multistage wave beam, select a kind of shaped-beam according to the space time characterisitic parameter, or according to the space time characterisitic parameter beam optimization criterion is set and obtains a kind of shaped-beam.

Preferable, described space time characterisitic parameter is estimated to comprise: arrival bearing's angle variation range delta DOA ^(k)The span G of the maximum direction normalized gain of received signal _Min ^(k)The perhaps span of the beamwidth of the maximum direction of received signal

The perhaps combination of above-mentioned parameter.

Preferable, the combination of described above-mentioned parameter comprises: calculate arrival bearing's angle variation range delta DOA ^(k)Span G with the maximum direction normalized gain of received signal _Min ^(k), perhaps arrival bearing's angle variation range delta DOA ^(k)Span with the beamwidth of the maximum direction of received signal

Preferable, described step of carrying out the estimation of wave beam forming weight vector comprises: according to space time characterisitic parameter Δ DOA ^(k), G _Min ^(k)Or

Judge whether to satisfy optimal conditions, if, then set the principle of optimality and carry out beam optimization according to the principle of optimality, obtain the wave beam forming weight vector; Otherwise, obtain the wave beam forming weight vector according to the conventional wave bundle shaping method.

Preferable, described step of carrying out the estimation of wave beam forming weight vector comprises:

A) judge Δ DOA ^(k)〉=ε _DOAIf set up, then execution in step b), otherwise execution in step c);

B), the beam optimization criterion is set, in many group wave beam forming weight vectors, selects to make the wave beam maximum gain direction at Δ DOA ^(k)Center position DOA ₀ ^(k), and make the half power lobe width near Δ DOA ^(k)The wave beam forming weight vector, execution in step g);

C), if second parameter of input is G _Min ^(k), then judge $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_G,$ If set up, then execution in step d), otherwise execution in step e); Perhaps, if the input second parameter be

Then judge

If set up, then execution in step d), otherwise execution in step e);

D), the beam optimization criterion is set, if second parameter of input is G _Min ^(k), then in many group wave beam forming weight vectors, select to make the maximum gain direction of wave beam at Δ DOA ^(k)Center position DOA ₀ ^(k), figuration gain is near G _Min ^(k)The wave beam forming weight vector, and the half power lobe width is greater than ε _DOAPerhaps, if the input second parameter be

Then in many group wave beam forming weight vectors, select to make the wave beam maximum gain direction at Δ DOA ^(k)Center position, make its half power lobe width the most approaching

The wave beam forming weight vector; Execution in step g);

E), use traditional beam form-endowing method, make the beam center direction at DOA ₀ ^(k)

G), optimize shaped-beam, obtain the figuration weight vector according to the beam optimization criterion that is provided with;

Wherein, ε _DOA, ε _GAnd ε _HPBe respectively parameter Δ DOA ^(k), G _Min ^(k)With

The thresholding of parameter.

Preferable, described step of carrying out the estimation of wave beam forming weight vector comprises: set the wave beam grade according to gain and half power lobe width range value, again according to space time characterisitic parameter Δ DOA ^(k)And G _Min ^(k)Perhaps according to Δ DOA ^(k)With

Select corresponding wave beam grade.

Preferable, described step of carrying out the estimation of wave beam forming weight vector comprises:

H), judge Δ DOA ^(k)〉=ε _{DOA, 2}If, set up, then select third level wave beam, otherwise, execution in step j);

J), judge

Perhaps $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_{G,2},$ If set up, then select third level wave beam, otherwise, execution in step k);

K), Δ DOA ^(k)≤ ε _{DOA, 1}If, set up, then execution in step 1), otherwise, select second level wave beam;

L), judge Perhaps $G_{\min }^{\left(k\right)}\≥{\mathrm{\ϵ}}_{G,1},$ If set up, then select first order wave beam, otherwise, select second level wave beam.

ε wherein _{DOA, 1}, ε _{DOA, 2}, ε _{G, 1}, ε _{G, 2}, ε _{HP, 1}And ε _{HP, 2}Be respectively Δ DOA ^(k), G _Min ^(k)With First order thresholding and second level thresholding, first order wave beam, second level wave beam and third level wave beam are divided according to gain and half power lobe width.

Utilize the present invention, can decide the wave beam forming of antenna according to the characteristic of environment, especially under the situation of complicated wireless channel.

Description of drawings

Figure 1 shows that the schematic diagram of device of the wireless channel down beam shaping of embodiments of the invention;

Fig. 2 is the flow chart of method of the wireless channel down beam shaping of embodiments of the invention;

Fig. 3 is the sub-process figure of the beam optimization of embodiments of the invention;

Fig. 4 is the sub-process figure of the beam selection of embodiments of the invention;

Fig. 5 is the schematic diagram of the used even circular array of unit 8 of embodiments of the invention;

Fig. 6 is the optimization beam pattern that utilizes the even circular array of the used unit 8 of embodiments of the invention to obtain;

Fig. 7 is 3 grades of used beam patterns of the even circular array of the used unit 8 of embodiments of the invention.

Embodiment

Implement and understand the present invention for the ease of persons skilled in the art, describe method and apparatus of the present invention with reference to accompanying drawing by embodiment respectively below.

Figure 1 shows that the schematic diagram of device of the complicated wireless channel down beam shaping of embodiments of the invention.

Comprise following each several part:

Ka antenna element 1-1-1-Ka.The radiation characteristic of antenna element satisfies the sub-district and covers.The omnidirectional antenna units of omni cell and cover the sector antenna unit of many sector systems for example.Up, antenna element receives the space electromagnetic signal, comprises all users' of this sub-district signal (comprising data and training sequence) and the interference signal of outer sub-district and the various noise signals in space; At descending each user's downstream signal of then launching, because in the weighting difference of each user on different antennae, for different user, antenna array system has different radiation characteristics.

With, Ka transmit-receive switch 2-1-2-Ka is connected with antenna element respectively.In tdd systems, according to system clock, antenna is changed in the transmitting-receiving process.Then do not need this type of transmit-receive switch in the system that does not use duplexer.

And Ka channel estimator 3-1-3-Ka is connected with K transmit-receive switch respectively.According to the training sequence that sends, the channel impulse response of estimating user.The present invention to channel estimator without limits.For example can adopt Steine estimator and various versions thereof etc.

Related operation device 4, its input are the outputs of all channel estimators 3.The subscriber channel impulse response of estimating is carried out related operation in spatial domain, export each user's spatial correlation matrix;

Spectrum estimator 5 is connected with the output of related operation device 4.Carry out the space collection of illustrative plates estimation of incoming wave according to user's spatial correlation matrix, the output of this device is some spatial character parameters.

The spatial character parameter that parameter estimator 6 receives from spectrum estimator 5 is carried out the estimation of space time characterisitic parameter according to the direction power spectrum of estimating.

Beam optimization/selector 7 receives the user's space time response parameter of parameter estimator 6 outputs, and according to the space time characterisitic parameter figuration weight vector is carried out following processing:

1. beam optimization: shaped-beam is optimized, makes it can reach best reception to user's incoming wave signal;

2. beam selection: in some weight vectors that set in advance, select, from least two kinds of shaped-beams, obtain a kind of shaped-beam, make it can reach best reception to user's incoming wave signal.

Like this, the weight vector of beam optimization/selector 6 each user wave beam figuration of output.

Beamformer 8.Transmitting of each user carried out figuration and the data behind the figuration merged each antenna element of process transmitting-receiving control switch feed-in.

The descending beam form-endowing method of wireless channel environment disclosed by the invention at first utilizes antenna element, transmit-receive switch, channel estimator, related operation device and spectrum estimator to obtain the space time characteristic of wireless channel; Then, beam optimization/selector and beamformer according to the space time characteristic of the wireless channel that obtains previously, adopt shaped-beam correspondingly to do downlink forming.

Fig. 2 is the flow chart of method of the complicated wireless channel down beam shaping of embodiments of the invention.

Wherein,

Step 1, each antenna channel is estimated: each antenna 1-1, the signal e that 1-ka receives ^{(i, ka)}, ka=1 ..., Ka comprises 3 parts, the useful signal of this sub-district, the interference signal of outer sub-district and noise, and wherein the useful signal of this sub-district comprises multi-user's emission data and training sequence.Signal arrives channel estimator 3 through transmit-receive switch 2, and here, i is the sequence number of frame.

In channel estimator 3, utilize the multi-user's who receives training sequence part to carry out the estimation of channel impulse response.Though described concrete method with embodiment, the present invention can use any other the mode and method of channel estimating.Channel estimator has been exported each antenna upper signal channel impulse response of estimating

K=1 ..., K, ka=1 ..., the normalized form h of Ka ^{(i, k, ka)}K is K user.

${\tilde{h}}^{(i,k,\mathrm{ka})}={[{\tilde{h}}_1^{(i,k,\mathrm{ka})},{\tilde{h}}_2^{(i,k,\mathrm{ka})},...,{\tilde{h}}_W^{(i,k,\mathrm{ka})}]}^T$ K=1 ..., K, ka=1 ..., Ka (formula 1)

$h^{(i,k,\mathrm{ka})}=\frac{{\tilde{h}}^{(i,k,\mathrm{ka})}}{\mathrm{norm}\left({\tilde{h}}^{(i,k,\mathrm{ka})}\right)}$ (formula 2)

Wherein, W is that channel estimation window is long.

Here, the channel estimating information of representing the user with channel estimate matrix.The channel estimate matrix of user k is expressed as follows

K=1 ..., K (formula 3)

Step 2, user's space correlation matrix estimation:, calculated each user's spatial correlation matrix at related operation device 4

$R_{\mathrm{xx}}^{(i,k)}=H^{(i,k)H}\·H^{(i,k)}$ K=1 ..., K (formula 4)

Computing () ^HRepresenting matrix grip the transposition computing altogether.

Carry out beam optimization or selection with concrete numerical value according to parameter.

Step 3, the spatial power directional spectrum is estimated:

According to user's coherence matrix R _Xx ^{(i, k)}Estimation, can obtain arrival bearing's power collection of illustrative plates of every frame,

K=1 ..., K (formula 5)

Wherein,

It is array response vector

(formula 6)

Step 4, the space time characterisitic parameter is estimated:

Space time characterisitic parameter to channel in parameter estimator 6 is estimated.The present invention proposes parameter, the i.e. variation of the variation of incoming wave angle, incoming wave power spectrum chart maximum gain and the variation of incoming wave power spectrum chart width of 3 reflection channel space time responses.These 3 parameters can reflect the space time characteristic of channel, can carry out beam optimization or selection according to the concrete numerical value of parameter.These 3 parameters all will be calculated according to arrival bearing's power spectrum chart of user:

The maxgain value of arrival bearing's power collection of illustrative plates is

K=1 ..., K (formula 7)

The incoming wave angle of every frame

K=1 ..., K (formula 8)

The half-power beam width of arrival bearing's power collection of illustrative plates of every frame

K=1 ..., K (formula 9)

K=1 ..., K (formula 10)

Top process is the processing to present frame, and the characterisitic parameter that finally provides is the excursion of characterisitic parameter in some frames of present frame, comprising:

Parameter 1) investigates the scope that arrival bearing's angle changes.

Arrival bearing's angle that each time slot is estimated is investigated the arrival bearing's angle variation range delta DOA that occurs in the record short time ^(k)Suppose

DOA ^(k)={ DOA ^{(i, k)}, DOA ^{(i-1, k)}..., DOA ^{(i-l+1, k}(formula 11-1)

Δ DOA ^(k)=max{DOA ^(k)}-min{DOA ^(k)(formula 11-2)

The central angle of incoming wave angle

${\mathrm{DOA}}_0^{\left(k\right)}=\frac{\max \left\{{\mathrm{DOA}}^{\left(k\right)}\right\}+\min \left\{{\mathrm{DOA}}^{\left(k\right)}\right\}}{2}$ (formula 11-3)

Parameter 2) minimum value of investigation maximum gain.

Arrival bearing's power collection of illustrative plates that each time slot is estimated is investigated, obtained the span G of the maximum direction normalized gain of received signal _Min ^(k)

$p_{\max }^{\left(k\right)}=\{p_{\max }^{(i,k)},p_{\max }^{(i-1,k)},...,p_{\max ,}^{(i-N+1,k)}\}$ (formula 12-1)

$G_{\min }^{\left(k\right)}=\min \left\{p_{\max }^{\left(k\right)}\right\}$ (formula 12-2)

Parameter 3) maximum of investigation beamwidth.

Arrival bearing's power collection of illustrative plates that each time slot is estimated is investigated, obtained the span of the beamwidth of the maximum direction of received signal

(formula 13-1)

(formula 13-2)

Compose any 2 in 3 parameters of estimator 6 outputs, i.e. Δ DOA ^(k)And G _Min ^(k)Perhaps Δ DOA ^(k)With Determine the beamforming algorithm of coupling according to parameter.

Step 5, the wave beam forming weight vector is estimated:

Step 4) has provided the parameter of reflection channel space time response, and step 5) is carried out descending wave beam forming according to the parameter that step 4) provides.The weight vector of wave beam forming can also can be selected in the weight vector that sets in advance according to parameter optimization.

Carry out the estimation or the selection of wave beam forming weight vector in beam optimization/selector 7, the weight vector that obtains is used for descending wave beam forming in beamformer 8.This aspect proposes the computational methods of two kinds of wave beam forming weight vectors.Method 1 be during according to channel empty characteristic real-time carry out beam optimization; Method 2 is that characteristic is selected in default multistage wave beam during according to channel empty.

Method 1) adopting the wave beam that is complementary with mobile channel space time characteristic to carry out downlink forming sends.Investigating the variation of arrival bearing's angle, maxgain value value or beamwidth value, all is in order to obtain a kind of shaped-beam, to make it can adapt to may changing of beam direction.Have only a kind of scheme of fixing shaped-beam to compare with traditional, this scheme can better adapt to complicated time varying channel.According to resulting spatial character parameter, optimize the sector beam that meets its parameter.Require the width of wave beam can cover the variation of incoming wave angle and the variation of beamwidth; The gain of wave beam is near the intermediate value of the excursion of incoming wave maxgain value.Method 1 is according to space time characterisitic parameter Δ DOA ^(k), G _Min ^(k)Or

Judge whether to satisfy optimal conditions, just judge whether it is the main direction that does not have tangible signal wave to reach, direction of arrival is the Complex Channel of a fast variable in time.If, then set the principle of optimality and carry out beam optimization according to the principle of optimality, obtain the wave beam forming weight vector; Otherwise, obtain the wave beam forming weight vector according to the conventional wave bundle shaping method.

Fig. 3 has provided the idiographic flow of method 1, is described below:

Step 511), judge Δ DOA ^(k)〉=ε _DOAIf, set up, then execution in step 512), otherwise execution in step 514); Wherein, ε _DOAIt is the threshold value of Δ DOA;

Step 512), the beam optimization criterion is set, makes the wave beam maximum gain direction at Δ DOA ^(k)Center position DOA ₀ ^(k), the half power lobe width approaches Δ DOA ^(k)

Step 513), the beam optimization device is optimized shaped-beam according to the beam optimization criterion that step is provided with, and obtains the figuration weight vector;

Step 514), the 2nd characterisitic parameter G _Min ^(k)Perhaps

Value, if the input second parameter be G _Min ^(k), then judge $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_G;$ If second parameter of input is

Then judge

If set up, then execution in step 515), otherwise execution in step 516); ε wherein _GBe G _Min ^(k)Threshold value, ε _HPBe Threshold value;

Step 515), the beam optimization criterion is set, if second parameter of input is G _Min ^(k), then the maximum gain direction of wave beam is at Δ DOA ^(k)Center position DOA ₀ ^(k), figuration gain approaches G _Min ^(k), and the half power lobe width is greater than ε _DOAIf second parameter of input is The wave beam maximum gain direction is at Δ DOA ^(k)Center position, its half power lobe width is approached

Execution in step 513);

Step 516), uses traditional beam form-endowing method, make the beam center direction at DOA ₀ ^(k)

Method 2) presses the multistage wave beam that corresponding spatial character parameter is selected corresponding level.

Method 2) be to set the wave beam grade, again according to space time characterisitic parameter Δ DOA according to gain and half power lobe width range value ^(k)And G _Min ^(k)Perhaps according to Δ DOA ^(k)With

Select corresponding wave beam grade.In order to simplify realization, we can only set the shaped-beam (such as, 3 other shaped-beams of level) of several grades.Have only a kind of scheme of fixing shaped-beam to compare with traditional, the figuration scheme of a plurality of wave beams can keep relative simplicity when better adapting to complicated time varying channel.

The optimization of multistage wave beam is considered the restricting relation of beamwidth and gain to realize that different coverages and gain are criterion, requires the half power lobe width of multistage wave beam to increase progressively successively, all will limit its beamwidth and gain every grade of wave beam.At n level wave beam, require the scope of beamwidth to be

The scope of gain is [G _Min ^(k), G _Max ^(k)], in this restriction, optimize multistage wave beam.For example we have proposed technical indicator as shown in table 1 to 3 grades of wave beams.

The technical indicator of table 13 grade wave beam

The wave beam rank	The 1st grade of wave beam	The 2nd grade of wave beam	The 3rd level wave beam
				Gain ranging (dB)	≥6	3～6	1～3
The half power lobe width range (°)	≤50	50～100	360

The selection criterion of wave beam is exactly to be included in the incoming wave of possible all directions within the shaped-beam.By the space time characterisitic parameter of channel, set up the relation between characterisitic parameter and the respective beam.Between characterisitic parameter and corresponding wave beam, set up corresponding relation, select shaped-beam according to corresponding relation.Suppose that shaped-beam is the N level, then to each characterisitic parameter, need be provided with N-1 thresholding with characterisitic parameter be divided into N interval and N level wave beam is corresponding one by one.If determine shaped-beam by investigating a plurality of characterisitic parameters, then shaped-beam with broad beam in the corresponding wave beams of all characterisitic parameters as shaped-beam.

Equally as an example, for the characterisitic parameter Δ DOA that imports with 3 grades of wave beams ^(k), G _Min ^(k)With

Because N=3, so set thresholding ε _DO4,1, ε _{DOA, 2}, ε _{G, 1}, ε _{G, 2}, ε _{HP, 1}And ε _{HP, 2}, (ε wherein _{DOA, 1}＜ε _{DOA, 2}, ε _{G, 1}＞ε _{G, 2}, ε _{HP, 1}＜ε _{HP, 2}) with characterisitic parameter Δ DOA ^(k)And G _Min ^(k)Be reference, beam selection is as shown in table 2, and the beam center direction is at Δ DOA ^(k)Center position.With characterisitic parameter Δ DOA ^(k)With

Be reference, beam selection is as shown in table 3, and the beam center direction is at Δ DOA ^(k)Center position.

Table 23 grade beam selection criterion 1

Table 33 grade beam selection criterion 2

The sub-process figure of beam selection is described below as shown in Figure 4:

Step 521), judge Δ DOA ^(k)〉=ε _{DOA, 2}If, set up, then select third level wave beam, otherwise, execution in step 522);

Step 522), judge Perhaps $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_{G,2},$ If set up, then select third level wave beam, otherwise, execution in step 523);

Step 523), Δ DOA ^(k)≤ ε _{DOA, 1}If, set up, then execution in step 524), otherwise, select second level wave beam;

Step 524), judge

Perhaps $G_{\min }^{\left(k\right)}\≥{\mathrm{\ϵ}}_{G,1},$ If set up, then select first order wave beam, otherwise, select second level wave beam.

In order to understand the present invention easily, to describe by a specific embodiment, this is based on, and the 3GPPTDD system realizes.

The even annular array that aerial array is made up of 8 omnidirectional radiation unit.The annular array radius is 0.6 times of carrier wavelength.4 users' of emulation situation, CDMA code channel of each CU, spread spectrum coefficient Q=16 adopts 16 mi damb l e sign indicating numbers as training sequence, and channel estimating is the Steine estimator through threshold processing; Channel circumstance adopts 3GPP case2 channel, i.e. 3 constant power multipaths, and 3 footpath angular distribution be [50 °, 50 °] evenly distribution.

We provide the processing to first user, and the parameter of getting 10 subframes processes, and user 1 center angle is 180 °, other 3 user perspective random distribution.

Carry out channel estimating, related operation and spectrum according to the midamble training sequence of up reception and estimate, characterisitic parameter when obtaining 10 subframes empty, characterisitic parameter is as shown in table 4.

In 3 parameters, select Δ DOA ⁽¹⁾With As investigating parameter, the value of two parameters is respectively 77 ° and 108 °, in addition arrival bearing's center angle

Provide as the figuration center position.

Table 4 space time characterisitic parameter changes

On the basis of analysis and investigation mobile channel space time characteristic, adopt the wave beam that is complementary with mobile channel space time characteristic to carry out downlink forming.A kind of selection is a method 1) by the shaped-beam of corresponding spatial character parameter optimization the best; A kind of selection is a method 1) select the multistage wave beam of corresponding level by corresponding spatial character parameter.

Method 1 is optimized best shaped-beam by corresponding space time characterisitic parameter

The space time characterisitic parameter thresholding of setting is as shown in table 5, according to thresholding that sets and beam optimization sub-process (Fig. 3), because Δ DOA ⁽¹⁾＞ε _DOA, therefore need to optimize a half power lobe width with Δ DOA ⁽¹⁾The wave beam that approaches is to cover all possible arrival bearing.

Table 5 beam optimization threshold parameter table

Parameter	ε DOA(°)	ε G(dB)	ε HP(°)	L
					Value	50	6.0	80	360

Fig. 6 has provided the result who optimizes, and the array power gain of this wave beam is approximately 5dB, and the 3dB beamwidth approximately is that 78 ° and arrival bearing's excursion meets substantially.Table 6 has provided the figuration parameter of this wave beam.

Table 6 is optimized the figuration parameter of wave beam

Method 2 is by the multistage wave beam of corresponding spatial character parameter selection corresponding level

Concrete scheme is that shaped-beam is divided into Three Estate.The technical indicator of wave beams at different levels sees Table 1, wherein, is the wave beam of traditional beamformer according to the 1st grade of wave beam, and the 3rd level wave beam is the wave beam of each unit constant amplitude homophase feed, and second level wave beam is the wave beam of optimizing according to desired technical indicator.The beam pattern of 3 grades of wave beams as shown in Figure 7.Formed well the shaped-beam of broadening successively in the space.The 2nd grade of about 4.7dB of beam gain wherein, 85 ° of beamwidths.

Table 7 has been set the thresholding of 3 grades of beam selection and has been set, the criterion of the beam selection that sets according to table 2,3 and the threshold parameter of the beam selection that table 7 sets, according to the flow process of table 7 and beam selection shown in Figure 4, the channel space time response parameter correspondence that provides in the example as can be known be the 2nd grade of 3 grades of wave beams.Compare with the result of beam optimization, the beamwidth that 3 grades of wave beams provide the recently variation of wave angle degree is slightly wideer.Table 8 has provided the figuration parameter of 3 grades of wave beams.

Table 73 grade beam selection threshold parameter table

Parameter	ε DOA，1 (°)	ε DOA，2 (°)	ε G，1(dB)	ε G，2(dB)	ε HP，1 (°)	ε HP，2 (°)
							Value	40	80	7	4	50	100

The figuration parameter of three grades of wave beams of table 8

Though above-mentionedly only talked about the situation of setting 3 grades of wave beams for example, as required, also can set multistage wave beams such as 2 grades or 4 grades.Its principle is identical, this not tired stating.

Though described the present invention by embodiment, those of ordinary skills know, the present invention has many distortion and variation and do not break away from spirit of the present invention, therefore, wish that appended claim comprises these distortion and variation and do not break away from spirit of the present invention.

Claims (11)

1, a kind of down beam shaping method of wireless channel is used to have the system of a plurality of antennas and R-T unit, it is characterized in that described method comprises step:

Described a plurality of antennas are carried out channel estimating;

According to the channel estimating of described a plurality of antennas, carry out the user's space parameter Estimation;

According to described spatial parameter estimation, carry out the wave beam forming weight vector and estimate, from least two kinds of shaped-beams, obtain a kind of shaped-beam;

Estimate the control wave beam forming according to the wave beam forming weight vector.

2, the down beam shaping method of wireless channel as claimed in claim 1 is characterized in that, the described user's space parameter Estimation of carrying out comprises step:

Carry out the user's space correlation matrix estimation;

According to described channel estimating and correlation matrix estimation, carry out the spatial power directional spectrum and estimate;

Estimate according to described spatial power directional spectrum, carry out the space time characterisitic parameter and estimate.

3, the down beam shaping method of wireless channel as claimed in claim 2, it is characterized in that, describedly from least two kinds of shaped-beams, obtain a kind of shaped-beam and comprise: from multistage wave beam, select a kind of shaped-beam according to the space time characterisitic parameter, or according to the space time characterisitic parameter beam optimization criterion is set and obtains a kind of shaped-beam.

4, the down beam shaping method of wireless channel as claimed in claim 2 is characterized in that, described space time characterisitic parameter is estimated to comprise: calculate arrival bearing's angle variation range delta DOA ^(k)The span G of the maximum direction normalized gain of received signal _Min ^(k)The perhaps span of the beamwidth of the maximum direction of received signal

The perhaps combination of above-mentioned parameter.

5, the down beam shaping method of wireless channel as claimed in claim 4 is characterized in that, the combination of described above-mentioned parameter comprises: calculate arrival bearing's angle variation range delta DOA ^(k)Span G with the maximum direction normalized gain of received signal _Min ^(k), perhaps arrival bearing's angle variation range delta DOA ^(k)Span with the beamwidth of the maximum direction of received signal

6, the down beam shaping method of wireless channel as claimed in claim 5 is characterized in that, described step of carrying out the estimation of wave beam forming weight vector comprises: according to space time characterisitic parameter Δ DOA ^(k), G _Min ^(k)Or

Judge whether to satisfy optimal conditions, if, then set the principle of optimality and carry out beam optimization according to the principle of optimality, obtain the wave beam forming weight vector; Otherwise, obtain the wave beam forming weight vector according to the conventional wave bundle shaping method.

7, the down beam shaping method of wireless channel as claimed in claim 6 is characterized in that, described step of carrying out the estimation of wave beam forming weight vector comprises:

A) judge Δ DOA ^(k)〉=ε _DOAIf set up, then execution in step b), otherwise execution in step c);

B), the beam optimization criterion is set, in many group wave beam forming weight vectors, selects to make the wave beam maximum gain direction at Δ DOA ^(k)Center position DOA ₀ ^(k), and make the half power lobe width near Δ DOA ^(k)The wave beam forming weight vector, execution in step g);

C), if second parameter of input is G _Min ^(k), then judge $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_G,$ If set up, then execution in step d), otherwise execution in step e); Perhaps, if the input second parameter be

Then judge

If set up, then execution in step d), otherwise execution in step e);

D), the beam optimization criterion is set, if second parameter of input is G _Min ^(k), then in many group wave beam forming weight vectors, select to make the maximum gain direction of wave beam at Δ DOA ^(k)Center position DOA ₀ ^(k), figuration gain is near G _Min ^(k)The wave beam forming weight vector, and the half power lobe width is greater than ε _DOAPerhaps, if the input second parameter be

Then in many group wave beam forming weight vectors, select to make the wave beam maximum gain direction at Δ DOA ^(k)Center position, make its half power lobe width the most approaching

The wave beam forming weight vector; Execution in step g);

E), use traditional beam form-endowing method, make the beam center direction at DOA ₀ ^(k)

G), optimize shaped-beam, obtain the figuration weight vector according to the beam optimization criterion that is provided with; Wherein, ε _DOA, ε _GAnd ε _HPBe respectively parameter Δ DOA ^(k), G _Min ^(k)With

Thresholding.

8, the down beam shaping method of wireless channel as claimed in claim 5, it is characterized in that, described step of carrying out the estimation of wave beam forming weight vector comprises: set the wave beam grade according to gain and half power lobe width range value, again according to space time characterisitic parameter Δ DOA ^(k)And G _Min ^(k)Perhaps according to Δ DOA ^(k)With

Select corresponding wave beam grade.

9, the down beam shaping method of wireless channel as claimed in claim 8 is characterized in that, described step of carrying out the estimation of wave beam forming weight vector comprises:

H), judge Δ DOA ^(k)〉=ε _{DOA, 2}If, set up, then select third level wave beam, otherwise, execution in step j);

J), judge

Perhaps $G_{\min }^{\left(k\right)}\≤{\mathrm{\ϵ}}_{G,2},$ If set up, then select third level wave beam, otherwise, execution in step k);

K), Δ DOA ^(k)≤ ε _{DOA, 1}If, set up, then execution in step 1), otherwise, select second level wave beam;

L), judge

Perhaps $G_{\min }^{\left(k\right)}\≥{\mathrm{\ϵ}}_{G,1},$ If set up, then select first order wave beam, otherwise, select second level wave beam,

ε wherein _{DOA, 1}, ε _{DOA, 2}, ε _{G, 1}, ε _{G, 2}, ε _{HP, 1}And ε _{HP, 2}Be respectively Δ DOA ^(k), G _Min ^(k)With

The first order thresholding of parameter and second level thresholding, first order wave beam, second level wave beam and third level wave beam are divided according to gain and half power lobe width.

10, a kind of down beam shaping device of wireless channel comprises:

A plurality of transceiver channel estimation units are used to export a plurality of transceiver channels and estimate;

Relevant apparatus is used for described a plurality of transceiver channels are estimated to be correlated with;

The channel parameter estimation device is used for according to correlated results, obtains channel parameter estimation;

Beam size enlargement apparatus is used for according to channel parameter estimation, to wave beam forming, obtains a kind of shaped-beam from least two kinds of shaped-beams;

It is characterized in that described a plurality of transceiver channel estimation units comprise a plurality of antennas; A plurality of transmit-receive switches are coupled to described a plurality of antenna and beam size enlargement apparatus; A plurality of channel estimators are coupled to a plurality of transmit-receive switches and relevant apparatus;

Described channel parameter estimation device comprises the spectrum estimator and the parameter estimator that intercouple.

11, the down beam shaping device of wireless channel as claimed in claim 10 is characterized in that, described beam size enlargement apparatus comprises: the beam optimization device is used for carrying out beam optimization according to channel parameter estimation; And/or the beam selection device, be used for selecting to obtain a kind of shaped-beam from least two kinds of shaped-beams according to channel parameter estimation.

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