CN101442350A

CN101442350A - Estimation method for arrival angle

Info

Publication number: CN101442350A
Application number: CNA2007101880884A
Authority: CN
Inventors: 丁婷
Original assignee: ZTE Corp
Current assignee: Rugao Changjiang science and Technology Industry Co Ltd
Priority date: 2007-11-22
Filing date: 2007-11-22
Publication date: 2009-05-27
Anticipated expiration: 2027-11-22
Also published as: CN101442350B

Abstract

The invention discloses a method for estimating a direction of arrival. When the DOA estimation is performed on a target user in a cell, channel impulse response matrices ch_hn<k[j]>s of various interference users of adjacent cells are calculated, and an interference matrix HDI is generated according to the ch_hn<k[j]>s; an inverse matrix of a spatial covariance matrix of the HDI is used to be left multiplied by a spatial covariance matrix of the target user to obtain a modified spatial covariance matrix Rmodify of the target user; the Rmodify is used to calculate the direction of arrival of the target user; and the HDI consists of a column corresponding to maximum tap power values in the ch_hn<k[j]>s or is generated through the adding of the ch_hn<k[j]>s. The method uses the spatial covariance matrix of the HDI to modify the spatial covariance matrix of the target user, which effectively inhibits the strong interference caused by the interference users and improves the estimation accuracy of the DOA.

Description

A kind of direction of arrival estimation method

Technical field

The present invention relates to a kind of ripple and reach angle (Direction of Arrival is called for short DOA) method of estimation.

Background technology

As the key technology in TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) system, smart antenna has obtained more and more deep research in recent years.Signal processing technology was enlarging cell range, is improving power system capacity, is improving the system spectrum utilance, reducing transmitting power and is reducing aspect such as user's interference to have shown huge potential when smart antenna combined form empty with traditional time-domain signal treatment technology.DOA estimates it is the basis that intelligent antenna wireless technological orientation and channel allocation realize.

Do not having under the strong jamming situation, existing DOA method of estimation based on up received signal power maximal criterion can obtain preferable performance.But exist under the more strongly disturbing situation of neighbor cell, user's space characteristics will be affected, and existing DOA method of estimation can't obtain perfect performance.

Summary of the invention

Technical problem to be solved by this invention is, overcomes the deficiencies in the prior art, proposes can obtain the comparatively DOA method of estimation of perfect performance under a kind of more strongly disturbing situation that has a neighbor cell.

In order to address the above problem, the invention provides a kind of direction of arrival estimation method, be applied to use in the wireless telecommunication system of smart antenna, it is characterized in that, when the targeted customer to this sub-district carries out the DOA estimation, calculate the channel impulse response matrix ch_h of each interference user of adjacent sub-district _n ^(k[j]), and according to each ch_h _n ^(k[j])Generate interference matrix H _DIUse H _DISpace covariance matrix R _DIInverse matrix premultiplication targeted customer's space covariance matrix obtain targeted customer's correction space covariance matrix R _ModifyUse R _ModifyCalculate targeted customer's arrival bearing;

Above-mentioned H _DIBy each ch_h _n ^(k[j])In the pairing row of maximum tap performance number form; Or by each ch_h _n ^(k[j])Addition generates;

Wherein, 1≤n≤N, N are this adjacent cells of cells number; 1≤j≤J, J are the interference user number of n adjacent sub-district of this sub-district; K[j] be the channel estimation window of j interference user correspondence of n adjacent sub-district.

In addition, described ch_h _n ^(k[j])Maximum tap performance number be ch_h _n ^(k[j])(:, the maximum in 2 norms w); Wherein, ch_h _n ^(k[j])(:, w) be ch_h _n ^(k[j])W row, 1≤w≤W, W are ch_h _n ^(k[j])Channel estimation window long.

In addition, described interference user is the user that signal power surpasses the signal power threshold value that sets in advance in the adjacent sub-district.

In addition, the maximum tap performance number of the channel impulse response matrix of described interference user is greater than the tap power threshold that sets in advance.

In addition, described targeted customer's space covariance matrix R adopts following method to obtain: R=ch_h ₀ ^(k)* (ch_h ₀ ^(k)) ^HWherein, ch_h ₀ ^(k)Be targeted customer's channel impulse response matrix, (ch_h ₀ ^(k)) ^HBe ch_h ₀ ^(k)Associate matrix; Described R _DIAdopt following method to obtain: R _DI=H _DI* (H _DI) ^HWherein, (H _DI) ^HExpression H _DIAssociate matrix.

In addition, according to described R _Modify, adopt one of following method to calculate described targeted customer's arrival bearing:

A) steering vector of computing array antenna, and use this steering vector scanning R _Modify, obtain the array steering vector angle of maximum power correspondence, i.e. targeted customer's arrival bearing; Or

B) steering vector of computing array antenna and R _ModifyEigenvalue of maximum characteristic of correspondence vector, and use this steering vector to scan above-mentioned R _ModifyEigenvalue of maximum characteristic of correspondence vector, obtain the array steering vector angle of maximum power correspondence, i.e. targeted customer's arrival bearing; Or

C) to R _ModifyCarry out estimating, obtain targeted customer's arrival bearing based on the spectrum of space covariance matrix.

In addition, described spectrum is estimated as: Bartlett composes estimation, and Capon composes estimation, and MUSIC composes estimation, one of ESPRIT spectrum.

In addition, described wireless telecommunication system is the TD-SCDMA system.

In sum, the channel impulse response matrix that the present invention is based on interference user generates interference matrix, and use the space covariance matrix of this interference matrix that targeted customer's space covariance matrix is revised, effectively suppress interference user to the strong jamming that this community user caused, improved the DOA estimated accuracy.

Description of drawings

Fig. 1 is the direction of arrival estimation method flow chart that the embodiment of the invention is applied to the TD-SCDMA system;

Fig. 2 is for to carry out fixed beam method for scanning flow chart to space covariance matrix;

Fig. 3 carries out the method for scanning flow chart for the eigenvalue of maximum characteristic of correspondence vector to space covariance matrix.

Embodiment

Basic ideas of the present invention are, when the targeted customer to this sub-district carries out the DOA estimation, channel impulse response matrix construction interference channel impulse response matrix (abbreviation interference matrix) by the interference user in each neighbor cell, and use the covariance matrix (abbreviation interference covariance matrix) of interference matrix that targeted customer's covariance matrix is revised, the targeted customer's who use to revise covariance matrix carries out the DOA estimated result that fixed beam scanning or spectrum estimate to obtain the targeted customer, to suppress interference user in the adjacent sub-district to the interference of this sub-district.

Describe the present invention below in conjunction with drawings and Examples.

Fig. 1 is the direction of arrival estimation method flow chart that the embodiment of the invention is applied to the TD-SCDMA system.As shown in Figure 1, this method comprises following steps:

S101: the base station receives the multipath upward signal of this sub-district, according to the multipath upward signal that receives the targeted customer of this sub-district is carried out channel estimating, obtains targeted customer's channel impulse response matrix;

If the targeted customer is i user of this sub-district, this CU k[i] individual channel estimation window, then targeted customer's channel impulse response matrix ch_h ₀ ^(k[i])For:

ch_h_{0}^{(k [i])} = {[\begin{matrix} h_{0,1}^{(1, k [i])} & h_{0,2}^{(1, k [i])} & \cdot \cdot \cdot & h_{0, W}^{(1, k [i])} \\ h_{0,1}^{(2, k [i])} & h_{0,2}^{(2, k [i])} & \cdot \cdot \cdot & h_{0, W}^{(2, k [i])} \\ \cdot \cdot \cdot & \cdot \cdot \cdot & \cdot \cdot \cdot & \cdot \cdot \cdot \\ h_{0,1}^{(M, k [i])} & h_{0,2}^{(M, k [i])} & \cdot \cdot \cdot & h_{0, W}^{(M, k [i])} \end{matrix}]}_{M \times W}

Wherein, M represents the base station array antenna number, and W represents channel estimation window long (W=128).

S102: according to targeted customer's channel impulse response matrix ch_h ₀ ^(k[i])Calculate targeted customer's space covariance matrix R:

R＝ch_h ₀ ^(k[i])×(ch_h ₀ ^(k[i])) ^H；

Wherein, (ch_h ₀ ^(k[i])) ^HExpression ch_h ₀ ^(k[i])Associate matrix.

S103: the base station receives the multipath upward signal of adjacent sub-district, determines this community user is constituted the interference user of the adjacent sub-district of disturbing;

Each neighbor cell that above-mentioned adjacent sub-district is this sub-district.The interference user of determining adjacent sub-district can adopt present method in common, presets received signal power threshold value P_Signal, and the pairing user of upward signal who power in the adjacent sub-district is surpassed P_Signal is defined as interference user (corresponding signal is an interference signal).

S104: the channel impulse response matrix that obtains each interference user according to the channel estimating of each interference user;

If j interference user in the individual adjacent sub-district of n takies k[j] individual channel estimation window, then the channel impulse response matrix ch_h of this interference user _n ^(k[j])For:

ch_h_{n}^{(k [j])} = {[\begin{matrix} h_{n, 1}^{(1, k [j])} & h_{n, 2}^{(1, k [j])} & \cdot \cdot \cdot & h_{n, W}^{(1, k [j])} \\ h_{n, 1}^{(2, k [j])} & h_{n, 2}^{(2, k [j])} & \cdot \cdot \cdot & h_{n, W}^{(2, k [j])} \\ \cdot \cdot \cdot & \cdot \cdot \cdot & \cdot \cdot \cdot & \cdot \cdot \cdot \\ h_{n, 1}^{(M, k [j])} & h_{n, 2}^{(M, k [j])} & \cdot \cdot \cdot & h_{n, W}^{(M, k [j])} \end{matrix}]}_{M \times W}

Wherein,

Represent n adjacent sub-district k[j] channel impulse response of w tap correspondence m root antenna of individual channel estimation window.

1≤m≤M, 1≤n≤N, 1≤w≤W; M represents the base station array antenna number, and W represents channel estimation window long (W=128), and N is an adjacent sub-district number.

S105: according to the channel impulse response matrix ch_h of each interference user _n ^(k[j])Generate targeted customer's (this sub-district) interference matrix H _DI

Obtain interference matrix H _DIComprise following substep:

S105A: the maximum tap performance number of calculating each interference user:

If ch_h _n ^(k[j])(:, w) w of the channel impulse response matrix of j interference user in n sub-district of expression (k[j] individual channel estimation window) correspondence is listed as (row of w tap correspondence), then

ch_h_{n}^{(k [j])} (:, w) = {[\begin{matrix} h_{n, w}^{(1, k [j])} \\ h_{n, w}^{(2, k [j])} \\ \cdot \\ \cdot \\ \cdot \\ h_{n, w}^{(M, k [j])} \end{matrix}]}_{M \times 1};

Get

Promptly calculate

2 norms, as the channel impulse response power of w tap of the interference user that takies this channel estimation window.Calculate the channel impulse response performance number of each tap successively from 1 to W:

{| | ch_h_{n}^{(k [j])} (:, 1) | |}_{2}, {| | ch_h_{n}^{(k [j])} (:, 2) | |}_{2}, . . . . . ., {| | ch_h_{n}^{(k [j])} (:, W) | |}_{2};

Find the solution

\max {({| | ch_h_{n}^{(k [j])} (:, 1) | |}_{2}, {| | ch_h_{n}^{(k [j])} (:, 2) | |}_{2}, \cdot \cdot \cdot, {| | ch_h_{n}^{(k [j])} (:, W) | |}_{2})}

Obtain the maximum tap performance number P_maxvalue_w of k channel estimation window of n sub-district and the vectorial ch_h of channel impulse response of corresponding wmax tap correspondence _n ^(k[j])(:, wmax), i.e. channel impulse response matrix ch_h _n ^(k[j])Wmax row.

S105B: will be above the channel impulse response vector of the maximum tap performance number correspondence of each interference user (each channel estimation window) of tap power threshold P_throshold as interference matrix H _DIColumn-generation interference matrix H _DI

The channel impulse response vector of the maximum tap performance number correspondence of interference user is exactly the row of the prominent tap correspondence of channel impulse response in the channel impulse response matrix of this interference user.

Above-mentioned interference matrix H _DIBe the matrix of the capable W1 row of M, M is the base station array antenna number, and W1 is the number of maximum tap performance number greater than the channel impulse response matrix of the interference user of P_throshold.

Except the method that adopts step S105B, after the maximum tap performance number that obtains each interference user, also can adopt following steps to generate interference matrix:

S105B ': the channel impulse response matrix addition that maximum tap performance number is surpassed each interference user of tap power threshold P_throshold generates interference matrix H _DI

That is to say, when the maximum tap performance number of the channel impulse response matrix correspondence of interference user surpasses tap power threshold P_throshold, this interference user as interference user, with the channel impulse response matrix addition of each interference user, is obtained interference matrix H _DI

Above-mentioned interference matrix H _DIBe the matrix of the capable W row of M, M is the base station array antenna number, and W is that channel estimation window is long.

S106: calculate interference matrix H _DISpace covariance matrix, obtain interference covariance matrix R _DI

R _DI＝H _DI×(H _DI) ^H；

Wherein, (H _DI) ^HExpression H _DIAssociate matrix.

S107: use interference covariance matrix R _DIInverse matrix premultiplication targeted customer's space covariance matrix R, obtain targeted customer's correction space covariance matrix R _ModifyThat is:

R _modify＝R _DI ^-1×R。

S108: targeted customer's correction space covariance matrix is carried out fixed beam scanning (GOB) or this space covariance matrix eigenvalue of maximum characteristic of correspondence vector is scanned, obtain targeted customer's arrival bearing;

As shown in Figure 2, the said fixing beam sweeping method comprises following substep:

S108A: the steering vector of computing array antenna;

S108B: the steering vector with array antenna scans above-mentioned correction space covariance matrix, obtains the array steering vector angle of maximum power correspondence, i.e. targeted customer's arrival bearing.

As shown in Figure 3, above-mentioned eigenvalue of maximum characteristic of correspondence vector scan method comprises following substep:

S108A ': the steering vector of computing array antenna;

S108B ': the eigenvalue of maximum characteristic of correspondence vector that calculates above-mentioned correction space covariance matrix;

S108C ': the steering vector with array antenna scans above-mentioned eigenvalue of maximum characteristic of correspondence vector, obtains the array steering vector angle of maximum power correspondence, i.e. targeted customer's arrival bearing.

From the above mentioned, adopt step S105B to generate interference matrix H _DIBe the high power tap of considering interference user, with the channel impulse response vector of maximum tap performance number correspondence as H _DIRow; Adopt S105B ' to generate interference matrix H _DIBe each tap effect of taking all factors into consideration interference, the channel impulse response matrix addition that maximum tap performance number is surpassed each interference user of tap power threshold P_throshold generates H _DIThe method of step S105B is being calculated H with respect to S105B ' _DISpace covariance matrix R _DIThe time, computation amount.

Utilize interference matrix that this dual mode obtains based on maximum signal interference ratio criterion, the space covariance matrix R that obtains revising _ModifyJust be based on maximum signal interference ratio criterion in the space covariance matrix scope of revising, estimating to obtain the arrival bearing of desired user, effectively suppressing of the interference of adjacent community user this sub-district desired user.

In sum, the channel impulse response matrix that the present invention is based on interference user generates interference matrix, and use the space covariance matrix of this interference matrix targeted customer's space covariance matrix is revised, effectively suppressed interference user to interference that this community user caused.

Based on basic principle of the present invention, the foregoing description can also carry out multiple conversion, for example:

When in step S105B and S105B ', generating interference matrix, maximum tap performance number to interference user limits, when maximum tap performance number does not surpass tap power threshold P_throshold, the row with its correspondence do not add in the interference matrix, do not use corresponding channel impulse response matrix addition to generate interference matrix yet; In another embodiment of the present invention, can maximum tap performance number not carried out above-mentioned restriction, promptly no matter whether maximum tap performance number surpasses P_throshold, and all the row with its correspondence add interference matrix, or uses its corresponding channel impulse response matrix to generate interference matrix.

In addition, the method for step S108A～S108B, the S108A '～S108C ' in adopting the foregoing description, can also compose estimation, obtain targeted customer's arrival bearing above-mentioned correction space covariance matrix.

Above-mentioned spectrum is estimated: Bartlett (Robin Bartlett) spectrum, Capon (card friend) spectrum, MUSIC (multiple signal classification) spectrum and ESPRIT (estimation of invariable rotary signal parameter) spectrum, or other is based on the spectrum method of estimation of space covariance matrix.

In addition, except being applied to the TD-SCDMA system, DOA method of estimation of the present invention also can be applicable to the system of the employing smart antenna of other standard, and it is different that difference only is that the base station obtains each user's the method for aerial array channel impulse response matrix.

Claims

1, a kind of direction of arrival estimation method is applied to use in the wireless telecommunication system of smart antenna, it is characterized in that, when the targeted customer to this sub-district carries out the DOA estimation, calculates the channel impulse response matrix ch_h of each interference user of adjacent sub-district _n ^(k[j]), and according to each ch_h _n ^(k[j])Generate interference matrix H _DIUse H _DISpace covariance matrix R _DIInverse matrix premultiplication targeted customer's space covariance matrix obtain targeted customer's correction space covariance matrix R _ModifyUse R _ModifyCalculate targeted customer's arrival bearing;

2, direction of arrival estimation method as claimed in claim 1 is characterized in that, described ch_h _n ^(k[j])Maximum tap performance number be ch_h _n ^(k[j])(:, the maximum in 2 norms w);

Wherein, ch_h _n ^(k[j])(:, w) be ch_h _n ^(k[j])W row, 1≤w≤W, W are ch_h _n ^(k[j])Channel estimation window long.

3, direction of arrival estimation method as claimed in claim 1 is characterized in that, described interference user is the user that signal power surpasses the signal power threshold value that sets in advance in the adjacent sub-district.

4, direction of arrival estimation method as claimed in claim 1 is characterized in that, the maximum tap performance number of the channel impulse response matrix of described interference user is greater than the tap power threshold that sets in advance.

5, direction of arrival estimation method as claimed in claim 1 is characterized in that, described targeted customer's space covariance matrix R adopts following method to obtain: R=ch_h ₀ ^(k)* (ch_h ₀ ^(k)) ^HWherein, ch_h ₀ ^(k)Be targeted customer's channel impulse response matrix, (ch_h ₀ ^(k)) ^HBe ch_h ₀ ^(k)Associate matrix; Described R _DIAdopt following method to obtain: R _DI=H _DI* (H _DI) ^HWherein, (H _DI) ^HExpression H _DIAssociate matrix.

6, direction of arrival estimation method as claimed in claim 1 is characterized in that, according to described R _Modify, adopt one of following method to calculate described targeted customer's arrival bearing:

7, direction of arrival estimation method as claimed in claim 6 is characterized in that, described spectrum is estimated as: Bartlett composes estimation, and Capon composes estimation, and MUSIC composes estimation, one of ESPRIT spectrum.

8, direction of arrival estimation method as claimed in claim 1 is characterized in that, described wireless telecommunication system is the TD-SCDMA system.