CN103780288A - 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 using the estimated deviation. The two methods provided by the invention can reduce or even eliminate the deviation between the azimuth estimation value and the true value of the user.

Description

Signal processing method

The application is to be that September 29, application number in 2007 are 200710175431.1 the applying date, and denomination of invention is the divisional application of the application of " signal processing method ".

Technical field

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

Background technology

The realization of the mobile location service (LBS) based on customer location depends on the accurate estimation of user location.Existing user location method of estimation, estimates this user's orientation conventionally according to multiple arrival bearings' of user subscriber signal intensity.Concrete implementation method comprises:

The a certain user's who receives according to base station end aerial array Signal estimation channel impulse response, calculates downlink forming vector; According to calculating the downlink forming vector of gained, determine this user that base station end aerial array receives subscriber signal intensity at the different angles of arrival; Azimuth estimation value using the angle of arrival of subscriber signal intensity maximum as this user.

Wherein, it is relevant with the directive gain of respective antenna array that end aerial array in base station receives user's the intensity of different angle of arrival signals.Using in the system of fan antenna, the directive gain difference from the subscriber signal of different directions at reception antenna place, the closer to the normal direction of antenna, the directive gain of antenna is larger; Contrary more away from the normal direction of antenna, the directive gain of antenna is less.The difference of above-mentioned this directive gain causes the gain of subscriber signal of the different angles of arrival unbalanced, that is to say, in the time that the intensity of the unlike signal from user is identical, if the angle of arrival difference of these two signals, the intensity of these two signals that end aerial array in base station receives can be different due to the difference of directive gain, and then the deviation that causes user location to estimate.

Such as, the signal sending as user arrives base station end aerial array by 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, another arrival direction is in the direction of off-normal direction approximately 90 degree, in this case, because the directive gain near normal is large, and it is little away from the directive gain of normal, the intensity of two signals that therefore end aerial array in base station receives is very large by difference, causes the user location finally estimating near normal direction, departs from actual value.

In a word, due in sector antenna system, have the directive gain difference of antenna, therefore the range of scatter of the subscriber signal angle of arrival is larger, and the directive gain of antenna is just larger on the accuracy impact of user location estimated value.If it is inaccurate that user location is estimated, the realization of the LBS business based on customer location will directly be affected.

Summary of the invention

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

A kind of signal processing method that the embodiment of the present invention provides, comprising:

Directive gain according to downlink forming vector corresponding to the directivity vector of user's different angle of arrival subscriber signals, described user and reception antenna at the different angles of arrival, determines the intensity of described user's different angle of arrival subscriber signals;

According to the intensity of described different angle of arrival subscriber signals, determine described user's azimuth estimation value.

The another kind of signal processing method that the embodiment of the present invention provides, comprising:

Determine user's azimuth estimation value;

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

The deviation that utilization estimates, revises described user's azimuth estimation value.

From the description of above technical scheme, the first signal processing method provided by the invention, in the subscriber signal strength g of determining the different angles of arrival that base station end aerial array receives _itime, the difference of the directive gain of consideration reception antenna on the different angles of arrival, afterwards again according to the g determining _idetermine user location estimated value, and then can reduce the estimated bias of user location.Another kind of signal processing method provided by the invention, first adopt user location method of estimation of the prior art to determine user location estimated value, and then poor according to two subscriber signal angles of arrival corresponding to default 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.

Accompanying drawing explanation

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

Fig. 2 is compared with prior art g of the embodiment of the present 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 bis-of the present invention.

Embodiment

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

The first signal processing method that the embodiment of the present invention provides, first adopt user location method of estimation of the prior art to determine user location estimated value, and then poor according to two subscriber signal angles of arrival corresponding to default 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 mono-of the present invention, and this flow process comprises:

Step 101, determines user location estimated value.

Specifically can adopt following two kinds of modes:

A kind of mode comprises:

Selected angle set, as θ _i=0～360 °, i=0,1 ..., directivity vector (steering vector) s of pre-defined selected angle _i, and meet || s _i||=1, i=0,1 ... ..;

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

Adopt formula (1) to calculate the directivity vector s of the signal of the different angles of arrival corresponding to same user _iinner product absolute value g with downlink forming vector w _i, g _ithe intensity of the subscriber signal of the different angles of arrival that sign base station end aerial array receives, but do not represent that different angle of arrival signals arrive the actual strength of base-station antenna array.

g _i＝||w ^Hs _i||； (1)

Wherein, w ^hfor the conjugate transpose of downlink forming vector w, s _ibe i the direction vector that subscriber signal is corresponding.

Selection makes g _iobtain peaked angle

as the estimated value of user location, as 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 the method identical with first kind of way to determine whole g corresponding to same user _i, determine afterwards and be greater than the g that sets threshold value _icorresponding all angles, as shown in formula (3):

{θ _j；g _j≥max(g _i)-Δ} (3)

Then, according to different weights, all angles of determining are weighted on average, draw user's azimuth estimation value, as 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 determine according to simulation result with threshold value Δ, be preset by system, such as getting Δ=3～5dB.

Step 102, poor according to two subscriber signal angles of arrival corresponding to 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:

In Fig. 2, dotted line represents to adopt the definite g of mode described in step 101 _iwith the curved line relation of the angle of arrival, as seen from the figure, maximum g in dotted line _icorresponding angle is-40 degree, supposes that predefined decay thresholding is 3dB, uses maximum g _ideduct 3dB, determine the poor Ω of two angles of arrival of this value correspondence, Ω is that in Fig. 2, curve shown in dotted line is being set beamwidth corresponding to decay thresholding, Ω is larger, the diffusion that represents user's angle of arrival is larger, and the impact that imbalance of the directive gain of reception antenna is estimated user location is just larger.

By the Ω substitution formula (5) of determining, 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,

represent when the angle of arrival to be

time, the directive gain of reception antenna; represent when the angle of arrival to be

time, the directive gain of reception antenna. the user location estimated value of determining 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 determined according to simulation result.

It should be noted that the directive gain function of reception antenna

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

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

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

Wherein Ω ₀for the angle of arrival of subscriber signal expands at 0 o'clock, corresponding beamwidth.Ω is the poor of two subscriber signal angles of arrival corresponding to decay thresholding set; Ω ₀for the angle of arrival of subscriber signal expands at 0 o'clock, corresponding beamwidth, Ω ₀for constant;

the user location estimated value of determining for step 101;

represent when the angle of arrival to be time, the directive gain of reception antenna;

represent when the angle of arrival to be

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

Step 103, the deviation of utilizing the user location estimated value estimating to exist, the azimuth estimation value that step 101 is determined is revised.

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

The second signal processing method that the embodiment of the present invention provides, in the subscriber signal strength g of determining the different angles of arrival that base station end aerial array receives _itime, consider the directive gain of the reception antenna difference on the different angles of arrival, adopt afterwards any in two kinds of modes described in step 101, according to the g determining _idetermine user location estimated value.

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

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

Step 401, the directivity vector s of the selected angle of definition _i, it is met || s _i|=1, i=0,1 ... ...

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

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

Step 403, the directive gain according to downlink forming vector corresponding to the directivity vector of this user's different angle of arrival subscriber signals, this user and reception antenna at the different angles of arrival, determines the strength g of this user's different angle of arrival subscriber signals _i.

One preferably specific implementation can be: adopt formula (8) to determine the strength g of a certain user's that base station end aerial array receives different angle of arrival subscriber signals _i.

g _i＝||w ^Hs _i||/|G(θ _i))| (8)

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

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

Step 404, according to all g that calculate _i, determine user location estimated value.

Concrete implementation can be:

Selection makes g _iobtain peaked angle

as the estimated value of user location, as shown in formula (2), can be also:

First determine and be greater than the g that sets threshold value _icorresponding all angles, then, according to the weight of setting, are weighted on average all angles of determining, draw user's azimuth estimation value, as shown in formula (3) and (4).

Utilize the method for this embodiment to realize simply, can reduce to a certain extent the deviation of user location estimated value.In Fig. 2, curve shown in solid line is the g definite by the method _iwith the relation of the subscriber signal angle of arrival, the user's that curve shown in Fig. 2 is corresponding physical location is at-45 degree, and utilizing the definite user location estimated value of art methods shown in dotted line is-40 degree, utilizes the definite user location estimated value of this embodiment for-43 degree.The method that this embodiment provides as can be seen here can reduce the deviation of user location estimated value.

This embodiment realizes simply, but it does not consider distribution and the impact of user location on user location estimated value of the subscriber signal angle of arrival.In order further to improve the accuracy of user location estimated value, can also determine after user location estimated value in step 404, further adopt the method described in step 102 and 103 to revise the user location estimated value of determining.

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:

In Fig. 2, solid line represents to adopt the definite g of method described in step 301-303 _iwith the curved line relation of the angle of arrival, as seen from the figure, maximum g in block curve _icorresponding angle is-43 degree, supposes that predefined decay thresholding is 3dB, uses maximum g _ideduct 3dB, determine the poor Ω of two angles of arrival of this value correspondence, Ω is that in Fig. 2, curve shown in solid line is being set beamwidth corresponding to decay thresholding, Ω is larger, the diffusion that represents user's angle of arrival is larger, and the impact that imbalance of the directive gain of fan antenna is estimated user location is just larger.

By the Ω substitution formula (5) of determining or formula (6), the existing deviation of estimation user location estimated value; The deviation that the user location estimated value that recycling estimates afterwards exists, the azimuth estimation value that step 404 is determined is revised, and specifically can utilize formula (7) to determine revised user location estimated value.Orientation estimated bias by the revised user of formula (7) is almost 0, therefore, utilize signal processing method that the embodiment of the present invention provides can significantly improve the accuracy of user location estimated value, for the realization of the LBS business based on customer location provides assurance.

In a word, the foregoing is only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (4)

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

Determine user's azimuth estimation value;

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

The deviation that utilization estimates, revises described user's azimuth estimation value.

2. the method for claim 1, is characterized in that, estimates the deviation of described user's azimuth estimation value existence, is specially:

Adopt following formula to calculate described deviation,

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

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

for described user's azimuth estimation value;

represent when the angle of arrival to be

time, the directive gain of reception antenna;

represent when the angle of arrival to be

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

3. the method for claim 1, is characterized in that, estimates the deviation of described user's azimuth estimation value existence, is specially:

Adopt following formula to calculate described deviation,

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

Wherein, Ω is the poor of two subscriber signal angles of arrival corresponding to decay thresholding set; Ω ₀for the angle of arrival of described user's subscriber signal expands at 0 o'clock, corresponding beamwidth; for described user's azimuth estimation value;

represent when the angle of arrival to be

time, the directive gain of reception antenna;

represent when the angle of arrival to be

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

4. the method for claim 1, is characterized in that, described definite user's azimuth estimation value, specifically comprises:

According to the directivity vector of user's different angle of arrival subscriber signals and downlink forming vector corresponding to described user, determine the intensity of described user's different angle of arrival subscriber signals;

Select in the intensity of described different angle of arrival subscriber signals, the angle of arrival corresponding to maximum is as described user's azimuth estimation value; Or,

First determine angle corresponding to intensity that is greater than the described subscriber signal of setting threshold value, again according to the weight of setting, all angles of determining are weighted on average afterwards, calculate described user's azimuth estimation value.

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