CN101399586B - Signal processing method - Google Patents

Abstract

The invention discloses a signal processing method which comprises the following steps: the strengths of user signals with different arrival angles of a user are determined according to directional vectors of the user signals with different arrival angles of the user, a downlink forming vector corresponding to the user and directional gains of a receiving antenna at different arrival angles; and an azimuth estimation value of the user is determined according to the strengths of the user signals with different arrival angles. Another signal processing method comprises the following steps: the azimuth estimation value of the user is determined; the deviation of the azimuth estimation value of the user is estimated according to the difference between two user signal arrival angles corresponding to a given attenuation threshold; and the azimuth estimation value of the user is corrected by the estimated deviation. The two methods can reduce or even eliminate the deviation between the azimuth estimation value and the true value of the user.

Description

Signal processing method

Technical field

The present invention relates to wireless communication technology, particularly signal processing method.

Background technology

Depend on the accurate estimation of user location based on the realization of the mobile location service (LBS) of customer location.Existing user location method of estimation is usually estimated this user's orientation according to a plurality of arrival bearings' of user subscriber signal intensity.Concrete implementation method comprises:

The a certain user's who receives according to the base station end aerial array signal estimated channel impulse response calculates the downlink forming vector; According to the downlink forming vector that calculates gained, confirm this user that the base station end aerial array receives subscriber signal intensity at the Different Arrival angle; The angle of arrival that subscriber signal intensity is maximum is as this user's azimuth estimation value.

Wherein, it is relevant with the directive gain of respective antenna array that the base station end aerial array receives user's the intensity of Different Arrival angle signal.In the system that uses fan antenna, different in the directive gain at reception antenna place from the subscriber signal of different directions, the closer to the normal direction of antenna, the directive gain of antenna is big more; Opposite more away from the normal direction of antenna, the directive gain of antenna is more little.The difference of above-mentioned this directive gain causes the gain of subscriber signal at Different Arrival angle unbalanced; That is to say; When from the intensity of user's unlike signal when identical; If the angle of arrival of these two signals is different, then the intensity of these two signals of receiving of base station end aerial array can be because the difference of directive gain and difference, and then causes the deviation of user location estimation.

Such as, the signal that sends as the user arrives the base station end aerial array through two different directions, and the intensity of these two signals is identical, and user's true bearing is near the intermediate angle of two arrival directions.An arrival direction of subscriber signal is in the normal direction of antenna; The direction that another arrival direction is spent in off-normal direction about 90, in this case, because big near the directive gain of normal; And it is little away from the directive gain of normal; Therefore the intensity of two signals receiving of base station end aerial array is very big with difference, and the user location that causes estimating at last departs from actual value near normal direction.

In a word, owing in sector antenna system, have the directive gain difference of antenna, so the range of scatter of the subscriber signal angle of arrival is big more, the directive gain of antenna is just big more to the accuracy influence of user location estimated value.If it is inaccurate that user location is estimated, with the LBS business realization that directly influences based on customer location.

Summary of the invention

In view of this, the embodiment of the invention provides two kinds of signal processing methods, reduces the deviation between user location estimated value and the actual value.

A kind of signal processing method that the embodiment of the invention provides comprises:

According to the directive gain of the corresponding downlink forming vector of the directivity vector of user's Different Arrival angle subscriber signal, said user and reception antenna, confirm the intensity of said user's Different Arrival angle subscriber signal at the Different Arrival angle;

According to the intensity of said Different Arrival angle subscriber signal, confirm said user's azimuth estimation value.

The another kind of signal processing method that the embodiment of the invention provides comprises:

Confirm user's azimuth estimation value;

Poor according to two corresponding subscriber signal angles of arrival of the decay thresholding of setting estimated the deviation that said user's azimuth estimation value exists;

The deviation that utilization estimates is revised said user's azimuth estimation value.

Description by above technical scheme can be known, first kind of signal processing method provided by the invention is in the subscriber signal strength g of confirming the Different Arrival angle that the base station end aerial array receives _iThe time, the difference of directive gain on the Different Arrival angle of consideration reception antenna is afterwards again according to the g that determines _iConfirm the user location estimated value, and then can reduce the estimated bias of user location.Another kind of signal processing method provided by the invention; At first adopt user location method of estimation of the prior art to determine the user location estimated value; And then poor according to two corresponding subscriber signal angles of arrival of preset decay thresholding, the deviation that estimation user location estimated value exists; The deviation that utilization estimates is revised the user location estimated value of determining, thereby can reduce the deviation of user location estimated value.

Description of drawings

Fig. 1 is the flow chart of signal processing method embodiment one of the present invention;

Fig. 2 is compared with prior art g of the embodiment of the invention _iCurved line relation comparison diagram with the angle of arrival;

Fig. 3 is the instantiation of reception antenna directive gain function curve;

Fig. 4 is the flow chart of signal processing method embodiment two of the present invention.

Embodiment

For making the object of the invention, technical scheme and beneficial effect clearer,, the present invention is done detailed description further below in conjunction with embodiment and accompanying drawing.

First kind of signal processing method that the embodiment of the invention provides; At first adopt user location method of estimation of the prior art to determine the user location estimated value; And then poor according to two corresponding subscriber signal angles of arrival of preset decay thresholding, the deviation that estimation user location estimated value exists; The deviation that utilization estimates is revised the user location estimated value of determining.

Fig. 1 is the flow chart of signal processing method embodiment one of the present invention, and this flow process comprises:

Step 101 is confirmed the user location estimated value.

Specifically can adopt following dual mode:

A kind of mode comprises:

The selected angle set is like θ _i=0～360 °, i=0,1 ..., define directivity vector (steering vector) s of selected angle in advance _i, and satisfy ‖ s _i‖=1, i=0,1 ... ..;

The a certain user's who receives according to the base station end aerial array signal estimated channel impulse response calculates downlink forming vector w;

Adopt formula (1) to calculate the directivity vector s of the signal at the corresponding Different Arrival angle of same user _iInner product absolute value g with downlink forming vector w _i, g _iThe intensity of the subscriber signal at the Different Arrival angle that sign base station end aerial array receives, but do not represent that the Different Arrival angle signal arrives the actual strength of base-station antenna array.

g _i＝‖w ^Hs _i‖；(1)

Wherein, w ^HBe the conjugate transpose of downlink forming vector w, s _iIt is the corresponding direction vector of i subscriber signal.

Selection makes g _iObtain peaked angle

As the estimated value of user location, shown in formula (2):

$\widehat{\mathrm{\θ}}=\underset{{\mathrm{\θ}}_i}{\arg }\left\{\max \left(g_i\right)\right\};---\left(2\right)$

Another kind of mode comprises:

Adopt and determine the corresponding whole g of same user with first kind of identical method of mode _i, determine afterwards greater than the g that sets threshold value _iAll corresponding angles, shown in formula (3):

{θ _j；g _j≥max(g _i)-Δ} (3)

Then,, all angles of determining are carried out weighted average, draw user's azimuth estimation value according to different weights, shown in formula (4):

$\widehat{\mathrm{\θ}}=\underset{{\mathrm{\θ}}_j;g_j\≥\max \left(g_i\right)-\mathrm{\Δ}}{\mathrm{\Σ}{\mathrm{\θ}}_j{\mathrm{\α}}_j}---\left(4\right)$

Wherein, weight coefficient α _jCan confirm according to simulation result with the threshold value Δ, preestablish by system, such as getting Δ=3～5dB.

Step 102, poor according to two corresponding subscriber signal angles of arrival of the decay thresholding of setting, the deviation that estimation user location estimated value exists.

With g shown in dotted lines in Figure 2 _iWith the curved line relation of the angle of arrival be example, the method for estimation user location estimated value existing deviation is described:

Dotted line representes to adopt the g that the said mode of step 101 is confirmed among Fig. 2 _iWith the curved line relation of the angle of arrival, visible from figure, maximum g in the dotted line _iCorresponding angle is-40 degree, supposes that predefined decay thresholding is 3dB, then uses maximum g _iDeduct 3dB; Confirm the poor Ω of two angles of arrival that this value is corresponding; Ω is that curve shown in the dotted line is being set the corresponding beamwidth of decay thresholding among Fig. 2; Ω is big more, and the diffusion of the expression user angle of arrival is big more, and then the imbalance of the directive gain of reception antenna is just big more to the user location estimation effect.

With the Ω substitution formula of determining (5), the existing deviation of estimation user location estimated value;

$\{G(\widehat{\mathrm{\θ}}-a\left(\mathrm{\Ω}\right))-G(\widehat{\mathrm{\θ}}+b\left(\mathrm{\Ω}\right))\}\×c,---\left(5\right)$

Wherein,

representes when the angle of arrival is

, the directive gain of reception antenna;

representes when the angle of arrival is

, the directive gain of reception antenna.The user location estimated value that

determines for step 101; A, b and c are predefined constant, and these constants change with the variation of reception antenna parameter, and its concrete numerical value can be confirmed according to simulation result.

Need to prove; The directive gain function of reception antenna

characterizes the variation of the directive gain of reception antenna with the angle of arrival, and the angle of arrival is 0 degree with the normal of antenna usually.Be illustrated in figure 3 as the instantiation of reception antenna directive gain function curve.

In addition, in reality realizes, even the angle of arrival of subscriber signal expands to 0; Its corresponding beamwidth Ω is not to be 0 yet, but tends to a definite minimum value, in order further to revise the user location estimated value; Can adopt formula (6), the existing deviation of estimation user location estimated value;

$\{G(\widehat{\mathrm{\θ}}-a(\mathrm{\Ω}-{\mathrm{\Ω}}_0))-G(\widehat{\mathrm{\θ}}+b(\mathrm{\Ω}-{\mathrm{\Ω}}_0))\}\×c,---\left(6\right)$

Ω wherein ₀For the angle of arrival of subscriber signal expands at 0 o'clock, corresponding beamwidth.Ω is poor for two corresponding subscriber signal angles of arrival of the decay thresholding of setting; Ω ₀For the angle of arrival of subscriber signal expands at 0 o'clock, corresponding beamwidth, Ω ₀Be constant;

The user location estimated value of determining for step 101;

The angle of arrival is worked as in expression

The time, the directive gain of reception antenna;

The angle of arrival is worked as in expression

The time, the directive gain of reception antenna; A, b and c constant for setting.A, b, c and Ω ₀Variation with the reception antenna parameter changes, and its concrete numerical value can be confirmed according to simulation result.

Step 103, the deviation that the user location estimated value that utilization estimates exists is revised the azimuth estimation value that step 101 is determined.

Concrete implementation method can for: utilize formula (7) to confirm revised user location estimated value value.

Second kind of signal processing method that the embodiment of the invention provides is in the subscriber signal strength g of confirming the Different Arrival angle that the base station end aerial array receives _iThe time, consider the difference of directive gain on the Different Arrival angle of reception antenna, adopt in the dual mode described in the step 101 any afterwards, according to the g that determines _iConfirm the user location estimated value.

Certainly, in order further to improve the accuracy of user location estimated value, can also adopt the described method of step 102 and step 103 that the user location estimated value of confirming is revised.

Fig. 4 is the flow chart of signal processing method embodiment two of the present invention, and this flow process comprises:

Step 401, the directivity vector s of the selected angle of definition _i, make it satisfy ‖ s _i‖=1, i=0,1 ... ...

Step 402, a certain user's who receives according to the base station end aerial array signal estimated channel impulse response calculates the corresponding downlink forming vector w of this user.

The method of calculating the downlink forming vector is a prior art, repeats no more here.

Step 403 according to the directive gain at the Different Arrival angle of the corresponding downlink forming vector of directivity vector, this user of this user's Different Arrival angle subscriber signal and reception antenna, is confirmed the strength g of this user's Different Arrival angle subscriber signal _i

A kind of preferable concrete implementation can for: adopt formula (8) to confirm the strength g of a certain user's that the base station end aerial array receives Different Arrival angle subscriber signal _i

$g_i=\left|\right|W^H{S}_i\left|\right|/\left|G\left({\mathrm{\θ}}_i\right)\right|---\left(8\right)$

Wherein, the directive gain function of setting reception antenna is G (θ), | G (θ _i) | for the angle of arrival is θ _iThe time corresponding reception antenna directive gain absolute value.The g that adopts formula (8) to calculate _iCan compensate to a certain extent because the user location estimated bias that the directive gain difference of reception antenna causes.

Certainly, the account form that formula (8) provides is a kind of preferred mode, in reality realizes, can also adopt alternate manner to consider the difference of directive gain on the Different Arrival angle of reception antenna, the feasible subscriber signal strength g of determining _iMore near actual value, and then reduce the deviation that user location is estimated.

Step 404 is according to all g that calculate _i, confirm the user location estimated value.

Concrete implementation can for:

Selection makes g _iObtain peaked angle

As the estimated value of user location, shown in formula (2)

Also can for:

At first determine greater than the g that sets threshold value _iAll corresponding angles then, according to the weight of setting, are carried out weighted average to all angles of determining, draw user's azimuth estimation value, shown in formula (3) and (4).

Utilize the method for this embodiment to realize simply can reducing the deviation of user location estimated value to a certain extent.Curve shown in the solid line is the g that confirms through this method among Fig. 2 _iWith the relation of the subscriber signal angle of arrival, the user's that curve shown in Figure 2 is corresponding physical location is at-45 degree, and user location estimated value such as the dotted line that utilizes art methods to confirm is depicted as-40 degree, and the user location estimated value of utilizing this embodiment to confirm is-43 degree.This shows that method that this embodiment provides can reduce the deviation of user location estimated value.

This embodiment realizes simply, but it does not consider the influence to the user location estimated value of distribution and the user location of the subscriber signal angle of arrival.In order further to improve the accuracy of user location estimated value, can also, step 404 further adopt step 102 and 103 described methods that the user location estimated value of determining is revised after determining the user location estimated value.

With g shown in Fig. 2 solid line _iWith the curved line relation of the angle of arrival be example, the method for estimation user location estimated value existing deviation is described:

Solid line representes to adopt the g that the said method of step 301-303 is confirmed among Fig. 2 _iWith the curved line relation of the angle of arrival, visible from figure, maximum g in the block curve _iCorresponding angle is-43 degree, supposes that predefined decay thresholding is 3dB, then uses maximum g _iDeduct 3dB; Confirm the poor Ω of two angles of arrival that this value is corresponding; Ω is that curve shown in the solid line is being set the corresponding beamwidth of decay thresholding among Fig. 2; Ω is big more, and the diffusion of the expression user angle of arrival is big more, and then the imbalance of the directive gain of fan antenna is just big more to the user location estimation effect.

With Ω substitution formula of determining (5) or formula (6), the existing deviation of estimation user location estimated value; Utilize the deviation of the user location estimated value existence that estimates afterwards again, the azimuth estimation value that step 404 is determined is revised, specifically can utilize formula (7) to confirm revised user location estimated value.DOA estimation deviation through the revised user of formula (7) is almost 0; Therefore; The signal processing method that utilizes the embodiment of the invention to provide can significantly improve the accuracy of user location estimated value, for the LBS business realization based on customer location provides assurance.

In a word, the above is merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. a signal processing method is characterized in that, comprising:

According to the directive gain of the corresponding downlink forming vector of the directivity vector of user's Different Arrival angle subscriber signal, said user and reception antenna, confirm the intensity of said user's Different Arrival angle subscriber signal at the Different Arrival angle;

According to the intensity of said Different Arrival angle subscriber signal, confirm said user's azimuth estimation value.

2. the method for claim 1 is characterized in that, the intensity of said definite user's Different Arrival angle subscriber signal is specially:

The intensity of said user's a angle of arrival subscriber signal; Equal conjugate transpose and said user's the inner product absolute value of directivity vector of this angle of arrival subscriber signal of said user's downlink forming vector, again divided by the absolute value of the directive gain of this angle of arrival reception antenna.

3. the method for claim 1 is characterized in that, said definite user's azimuth estimation value is specially:

Select in the intensity of said Different Arrival angle subscriber signal the angle of arrival that maximum is corresponding;

Perhaps, at first determine, then,, all angles of determining are carried out weighted average according to the weight of setting greater than the corresponding angle of the intensity of the said subscriber signal of setting threshold value.

4. the method for claim 1 is characterized in that, determine said user's azimuth estimation value after, this method further comprises:

Poor according to two corresponding subscriber signal angles of arrival of the decay thresholding of setting estimated the deviation that said user's azimuth estimation value exists;

The deviation that utilization estimates is revised said user's azimuth estimation value.

5. method as claimed in claim 4 is characterized in that, estimates the deviation of said user's azimuth estimation value existence, is specially:

Adopt following formula to calculate said deviation,

$\{G(\widehat{\mathrm{\θ}}-a\left(\mathrm{\Ω}\right))-G(\widehat{\mathrm{\θ}}+b\left(\mathrm{\Ω}\right))\}\×c,$

Wherein, Ω poor for two corresponding subscriber signal angles of arrival of the decay thresholding set;

is said user's azimuth estimation value;

representes when the angle of arrival is

, the directive gain of reception antenna;

representes when the angle of arrival is

, the directive gain of reception antenna; A, b and c constant for setting.

6. method as claimed in claim 4 is characterized in that, estimates the deviation of said user's azimuth estimation value existence, is specially:

Adopt following formula to calculate said deviation,

$\{G(\widehat{\mathrm{\θ}}-a(\mathrm{\Ω}-{\mathrm{\Ω}}_0))-G(\widehat{\mathrm{\θ}}+b(\mathrm{\Ω}-{\mathrm{\Ω}}_0))\}\×c,$

Wherein, Ω poor for two corresponding subscriber signal angles of arrival of the decay thresholding set; Ω ₀For the angle of arrival of said user's subscriber signal expands at 0 o'clock, corresponding beamwidth;

Azimuth estimation value for said user; The angle of arrival is worked as in expression The time, the directive gain of reception antenna;

The angle of arrival is worked as in expression

The time, the directive gain of reception antenna; A, b and c constant for setting.

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