JP2004282472A - Adaptive array antenna receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily realize beam formation even in a searcher part similarly as in a finger part and to maximize the merit of an adaptive array antenna by improving the receiving quality of the searcher part at the same time in an adaptive array antenna device. <P>SOLUTION: N pieces of radio receiving sections 102 convert RF signals from n pieces of antenna elements 101 into digital baseband signals. The searcher section 103 detects the position of a path for each beam. The finger section 104 conducts inverse spread processing in a timing detected by the searcher section 103, uses an adaptive algorithm such as an MMSE (Minimum Mean Squared Error) to form a beam and conducts maximum ratio composite. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６０】
ただし、
ｍ：ビームナンバー（ビーム形成器の数）
ｎ：アンテナ素子ナンバー
ｓ：ビーム数
ｔ：アンテナ素子数
とする。
【００６１】
上述の通り本発明は、直接拡散ＣＤＭＡ方式を用いた移動体通信システムの無線基地局に複数のアンテナ素子を有するアレイアンテナを設け、受信した信号に任意の振幅ウェイト、位相ウェイトを乗算して合成することで所望のビームパターンを等価的に形成するアダプティブアレイアンテナシステムの受信装置であり、その受信装置内のパス検出過程（サーチャー部）におけるビームパターン生成方法を示すものである。したがって、パス検出過程におけるビーム生成を容易に実現することを可能とし、従来のアダプティブアレイアンテナシステムにおいてボトルネックとなっていたパス検出精度を改善する。これはひいてはアダプティブアレイアンテナシステムの受信品質改善、通信容量の増大へとつながるものである。
【００６２】
本受信装置を用いれば、サーチャー部１０３におけるビーム形成を容易に実現することが可能となり、ダイナミックに変動するマルチパス環境下でもパスの検出精度を改善することができる。
【００６３】
なお本発明はアンテナ素子数、生成するビーム数、Ｆｉｎｇｅｒ数（ＲＡＫＥ合成に用いられるマルチパス数）に限定されるものではない。
【００６４】
図３はビーム指向特性を示す図である。
【００６５】
例として、アンテナ素子数４、ビーム数４のビームパターンを示しており、４ビームを形成した場合のビーム指向特性を示す図である。
【００６６】
横軸はアレイアンテナのビーム放射角度、縦軸はアレイアンテナのアンテナ利得を示す。サーチャー部ビーム形成器１０６の各ビーム出力であるビーム１、ビーム２、ビーム３、ビーム４に対応して、ビーム到来角に対する各ビームの利得を示している。
【００６７】
なお、ＲＡＫＥ合成後のＳＩＲ（信号対干渉電力比）を一定とするように送信電力制御が行われるＣＤＭＡシステムにおいては、本発明は送信電力の低減を可能とし、通信容量の増大をも実現することになる。
【００６８】
【発明の効果】
以上説明したように、本発明のアダプティブアレイアンテナ受信装置は、パス検出過程におけるビーム生成を容易に実現することができるので、アダプティブアレイアンテナにおいてボトルネックとなっていたパス検出精度を改善することができるという効果を有している。
【００６９】
また、パス検出精度の改善により、より多くのマルチパスを補足することが可能となるので、ＲＡＫＥ合成後の受信品質を大幅に改善することができるという効果を有している。
【図面の簡単な説明】
【図１】本発明のアダプティブアレイアンテナ受信装置の一つの実施の形態を示すブロック図である。
【図２】図１のビーム形成器の一例を示す詳細ブロック図である。
【図３】ビーム指向特性を示す図である。
【図４】従来のアダプティブアレイアンテナ受信装置を示すブロック図である。
【符号の説明】
１０１ アンテナ素子
１０２ 無線受信部
１０３ サーチャー部
１０４ フィンガー部
１０５ 相関器
１０６ サーチャー部ビーム形成器
１０７ 遅延プロファイル推定部
１０８ パス検出回路
１０９ ウェイト情報
１１０ 復調器
１１１ フィンガー部ビーム形成器
１１２ チャネル推定部
１１３ ウェイト制御部
１１４ ＲＡＫＥ合成回路
１１５ 参照信号
１１６ 受信タイミング通知信号
２０１ 乗算器
２０２ 加算器
２０３ アキュムレータ
２０４ ビームウェイト
４０１ サーチャー部
４０２ フィンガー部
４０５ 相関器
４０７ 遅延プロファイル推定部
４０８ パス検出回路
４０９ 受信タイミング通知信号[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an adaptive array antenna receiving apparatus, and more particularly, to an array antenna having a plurality of antenna elements provided in a wireless base station of a mobile communication system using a direct-spread CDMA (Code Division Multiple Access) method, and receiving a plurality of received signals. And an adaptive array antenna receiving apparatus that forms a desired beam pattern equivalently by multiplying by multiplication.
[0002]
[Prior art]
In general, the DS-CDMA (Direct Sequence-Code Division Multiple Access) is a method in which a plurality of communicators perform multiplex communication using the same frequency band, and each communicator uses a spread code. Separated and identified. In mobile communication, since the propagation path length of each received wave in multiplex wave propagation varies, multiplex waves having different propagation delay times are input to a plurality of receivers.
[0003]
Since the mobile station changes with respect to the base station, the delay profile (signal power distribution with respect to the delay time) also changes with time. In DS-CDMA communication, a path diversity effect is obtained by collecting and combining (RAKE combining) a plurality of multipath signals separated in time and having different propagation delay times, thereby improving reception characteristics.
[0004]
Alternatively, for a certain reception quality, the transmission power can be reduced by the diversity effect accompanying the RAKE combining.
[0005]
On the other hand, a sector antenna is currently used as a base station antenna of a mobile communication system using the DS-CDMA system. The sector antenna is an antenna that is in charge of each sector when the entire circumference (cell) of 360 degrees is divided into a plurality of sectors. This sectorization of the cell can remove the interference wave coming from the mobile station from outside the sector and reduce the interference to the mobile station outside the sector, but the arrival wave from other users in the same sector Becomes an interference wave. Interference from other users is a major factor in lowering channel capacity and deteriorating transmission quality.
[0006]
Research and development of an adaptive array antenna system is being performed as a technique for reducing the interference and improving the transmission quality. The adaptive array antenna system multiplies each antenna output by a beam weight (amplitude weight and phase weight) to form an antenna directivity pattern (beam) equivalently, and directs the beam in a desired wave arrival direction. Alternatively, by aiming null in the direction of arrival of the interference wave, it is possible to improve the gain of the desired wave and suppress the interference in the area.
[0007]
FIG. 4 is a block diagram showing a conventional adaptive array antenna receiving apparatus.
[0008]
Referring to FIG. 4, a signal received by antenna element 101 is frequency-converted to an intermediate frequency by radio receiving section 102, and then amplified by an automatic gain amplifier (not shown) to be converted into a baseband signal of an I / Q channel. After quadrature detection, the signal is converted into a digital signal by an A / D converter (not shown). One of the outputs of the wireless receiving unit 102 is sent to the searcher unit 401, and all the outputs of the plurality of wireless receiving units 102 are sent to the finger unit 402.
[0009]
In searcher section 401, first, code correlation of a desired wave signal included in the received signal is calculated by correlator 405, and delay profile estimating section 407 generates a delay profile (signal power distribution with respect to delay time) from the result. The path detection circuit 408 searches for the reception timing of the multipath signal from the delay profile and assigns it to each finger of the finger unit 402.
[0010]
On the other hand, finger section 402 performs despreading of the signal obtained from wireless receiving section 102 using reception timing notification signal 409 output from path detection circuit 408. Each Finger is a demodulator 110 (having demodulators for all antenna elements in each Finger), and performs despreading of the path allocated by the searcher unit 401, respectively. The despread signal is input to the finger beamformer 111 and multiplied by the beam weight calculated by the adaptive algorithm in the weight control unit 113 to form a beam equivalently. The output of finger section beamformer 111 is subjected to a channel estimation operation in channel estimation section 112 and output to RAKE combining circuit 114.
[0011]
The RAKE combining circuit 114 RAKE-combines each Finger output and sends it to a decoding circuit (not shown).
[0012]
Further, the error signal required by the adaptive control algorithm in weight control section 113 is obtained by multiplying reference signal 115 by the channel estimation value in channel estimation section 112 and then calculating the difference from the output of finger section beamformer 111. Generated by taking The weight control unit 113 forms a beam pattern equivalently by updating the beam weight so as to minimize the error signal, and causes the beam to follow the assigned path.
[0013]
As an algorithm for determining the weight in the weight control unit 113, an adaptive algorithm such as MMSE (Minimum Mean Squared Error) is used.
[0014]
In the conventional adaptive array antenna receiving apparatus, it is possible to improve the reception quality of a path for which synchronization is supplemented by beam forming in the finger section 402, but the searcher section for detecting the path Since a beam is not formed in 401, the searcher unit 401 may lose some paths when the environment is temporarily deteriorated. If the searcher unit 401 loses a path, the effect of RAKE combining in the finger unit 402 decreases, and it is not possible to expect a significant improvement in the sector antenna system in terms of speech quality.
[0015]
That is, in such a receiving apparatus, the finger unit 402 performs beam forming equivalently, and the demodulation accuracy can be improved by the sector antenna system. However, the searcher unit 401 cannot form a beam. However, in terms of path detection accuracy, it must be equivalent to a sector antenna system. If the searcher unit 401 loses a path, the reception quality of the finger unit 402 after RAKE combining also deteriorates.
[0016]
As described above, the reception quality of the conventional adaptive array antenna system has a serious problem.
[0017]
In addition to the above, the conventional adaptive array antenna receiving apparatus performs an averaging process of fluctuation due to fading of each path, stores it in a delay profile section, and performs averaging by adding and combining delay profiles of a plurality of antenna elements. The path detection rate of the searcher unit is improved (for example, see Patent Document 1).
[0018]
In some cases, a sector is divided by generating a multi-beam (a plurality of fixed beams that do not follow a path) by a searcher unit and a finger unit (for example, see Patent Document 2).
[0019]
[Patent Document 1]
JP-A-2002-84216 (pages 2-4, FIGS. 1 and 2)
[Patent Document 2]
JP-A-2001-345747 (pages 3 to 5, FIGS. 1 and 5)
[0020]
[Problems to be solved by the invention]
The above-described conventional adaptive array antenna receiving apparatus improves the path detection rate of the searcher unit by adding and combining the delay profiles of a plurality of antenna elements and averaging the delay profiles. If the number of antenna elements is large, the improvement in reception quality cannot be reduced to the rate of improvement in reception quality by beam formation at the finger part, and it is still impossible to take full advantage of the improvement in reception quality by beam formation. Since adaptive control for following a user who moves a beam is not performed for a plurality of beams in the above, there is a disadvantage that reception quality is reduced.
[0021]
In addition, generating a beam weight using an adaptive algorithm independently in the searcher unit has a disadvantage that it requires a huge amount of calculation and is difficult to realize.
[0022]
An object of the present invention is to make it easier to realize beam generation in a path detection process similar to that of a finger part in a searcher part in an adaptive array antenna receiving apparatus, and at the same time, to improve the path detection accuracy of a searcher part which has conventionally been a bottleneck. It is an object of the present invention to provide an adaptive array antenna receiving apparatus which improves reception quality after RAKE combining and makes the most of the advantages of the adaptive array antenna.
[0023]
[Means for Solving the Problems]
The first adaptive array antenna receiving apparatus of the present invention includes:
An array antenna having a plurality of antenna elements is provided in a wireless base station of a mobile communication system using a direct spread CDMA (Code Division Multiple Access) system, and a received signal is multiplied by an arbitrary amplitude weight and a phase weight to be synthesized. Thus, a desired beam pattern is equivalently formed.
[0024]
A second adaptive array antenna receiving apparatus according to the present invention includes:
In the adaptive array antenna receiver,
n (n is an integer of 1 or more) antenna elements;
N radio receivers for converting RF (Radio Frequency) signals from each of the antenna elements into digital baseband signals;
A searcher unit connected to these radio receiving units and detecting a path position as a reception timing for each beam;
A finger unit that performs despreading at the timing detected by the searcher unit, forms a beam using an MMSE (Minimum Mean Squared Error) adaptive algorithm, and performs maximum ratio combining;
It is characterized by having.
[0025]
A third adaptive array antenna receiving apparatus according to the present invention, wherein in the second adaptive array antenna receiving apparatus,
The searcher section includes:
a number of correlators corresponding to the n antenna elements, a searcher section beamformer corresponding to the number of beams to be generated, a delay profile estimator for generating a delay profile corresponding to the number of the beams, and the delay A path detecting circuit for detecting each path from the profile.
[0026]
The fourth adaptive array antenna receiving apparatus of the present invention is the second or third adaptive array antenna receiving apparatus,
The finger part is
It has a plurality of Fingers, and each Finger has a demodulator corresponding to the number of the antenna elements, a finger beamformer, a channel estimation unit, a weight control unit, and a RAKE combining circuit,
The weight control unit, as the weight information the optimal amplitude weight and phase weight determined by using the MMSE adaptive algorithm by the difference between the reference signal in the channel estimation unit, not only the finger beamformer, The searcher section beamformer is also notified.
[0027]
The fifth adaptive array antenna receiving apparatus according to the present invention, in the third or fourth adaptive array antenna receiving apparatus,
The searcher section beamformer,
By multiplying and combining the correlation values of the input signals of all the antenna elements input from the correlator with the weight information of the amplitude weight and the phase weight notified from the weight control unit, in the direction in which the path exists It is characterized by forming a beam equivalently.
[0028]
A sixth adaptive array antenna receiving apparatus according to the present invention, in the third adaptive array antenna receiving apparatus,
The delay profile estimator,
A delay profile for each beam is generated from an output of the searcher section beamformer, and the path detection circuit searches a reception timing of a multipath signal from the delay profile, and notifies a reception timing notification signal to the finger section. It is characterized by.
[0029]
A seventh adaptive array antenna receiving apparatus according to the present invention, in the second or third adaptive array antenna receiving apparatus,
The finger part is
It has a plurality of Fingers, and each Finger has a demodulator corresponding to the number of the antenna elements, a finger beamformer, a channel estimation unit, a weight control unit, and a RAKE combining circuit,
The demodulator performs despreading of the path of the signal obtained from the radio reception unit using the reception timing notification signal output by the path detection circuit, and the despread signal is input to the finger unit beamformer. A beam is equivalently formed by multiplying the beam weight calculated by the MMSE adaptive algorithm in the weight control unit.
[0030]
An eighth adaptive array antenna receiving apparatus according to the present invention, in the fourth or seventh adaptive array antenna receiving apparatus,
The output of the finger beamformer is subjected to a channel estimation operation in the channel estimator, output to the RAKE combining circuit, and in-phase combined.
[0031]
A ninth adaptive array antenna receiving apparatus according to the present invention, in the fourth adaptive array antenna receiving apparatus,
The weight control unit includes:
An error signal required by the adaptive control algorithm is generated by multiplying the reference signal and the channel estimation value by the channel estimator, and then taking the difference between the output of the finger beamformer and the error signal. It is characterized in that a beam pattern is equivalently formed by updating the beam weight so as to be minimized, and the beam follows the assigned path.
[0032]
The tenth adaptive array antenna receiving apparatus of the present invention is the adaptive array antenna receiving apparatus according to any one of the second to fourth or seventh aspects,
The beam weight in the searcher section beamformer generates a beam by using the value when notified as weight information from the weight control section in the finger section, and the weight is transmitted from the finger section at the time of initial synchronization supplementation. When there is no notification of the beam weight as information, a search is performed in all directions without forming a specific beam by setting all beam weights to the same value.
[0033]
An eleventh adaptive array antenna receiving apparatus according to the present invention, wherein in the third adaptive array antenna receiving apparatus,
The searcher section beamformer,
In order to perform the complex product sum for the n antenna elements, (4 × n) multipliers, (2 × n) adders, n antenna element nI outputs, and n antennas Two accumulators for adding and synthesizing the element nQ output and outputting an I signal and a Q signal respectively are built in, and the beam weight is multiplied by the multiplier to the nI output and the nQ output, and the correlation value of the antenna element is obtained. By combining the outputs, the phase between the elements is corrected to generate one beam for each, and the generated output becomes the reception correlation value output of the beam directed to the arrival direction of the path to be captured. Features.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0035]
FIG. 1 is a block diagram showing one embodiment of the adaptive array antenna receiving apparatus of the present invention.
[0036]
In FIG. 1, components corresponding to the components shown in FIG. 4 are given the same reference numerals or symbols, and description thereof will be omitted.
[0037]
The present embodiment shown in FIG. 1 has n antenna elements 101, n radio receiving units 102 for converting RF signals from each antenna element 101 into digital baseband signals, and a path position for each beam. (Receiving timing) and a searcher unit 103, perform despreading at the timing detected by the searcher unit 103, form a beam using an adaptive algorithm such as MMSE (Minimum Mean Squared Error), and form a beam And a finger unit 104 for performing ratio combining.
[0038]
The searcher unit 103 includes a number of correlators 105 corresponding to the number n of antenna elements 101, a searcher unit beamformer 106 corresponding to the number of beams to be generated, and a delay profile estimator 107 corresponding to the number of beams. And a path detection circuit 108 for detecting each path.
[0039]
Here, the delay profile indicates a signal power distribution with respect to the delay time.
[0040]
The finger unit 104 has a plurality of Fingers, and each Finger has a demodulator 110 corresponding to the number of antenna elements 101, a finger unit beamformer 111, a channel estimation unit 112, a weight control unit 113, And a RAKE combining circuit 114.
[0041]
Here, the Finger number indicates the number of multipaths used for RAKE combining.
[0042]
The searcher section 103 has a searcher section beamformer 106, and the searcher section beamformer 106 is notified of weight information 109 from a weight control section 113 in the finger section 104.
[0043]
As in the related art, the difference from the reference signal 115 is obtained by the channel estimation unit 112 in the finger unit 104, and the optimal amplitude weight and phase weight are obtained by using an adaptive algorithm such as MMSE (Minimum Mean Squared Error). The weight control unit 113 that has obtained the optimum amplitude weight and phase weight notifies the weight information 109 not only to the finger beam former 111 but also to the searcher beam former 106.
[0044]
On the other hand, the searcher section beamformer 106 receives the correlation values of the input signals of all the antenna elements 101 from the correlator 105, and outputs the weight information 109 of the amplitude weight and the phase weight notified from the weight control section 113 to the correlation value. Is multiplied and combined, a beam can be equivalently formed in the direction in which the path exists.
[0045]
FIG. 2 is a detailed block diagram showing an example of the beam former of FIG.
[0046]
The beamformer is included in the searcher unit 103 of FIG. 1 as a searcher unit beamformer 106 and the finger unit 104 is included as a finger unit beamformer 111, respectively. Since one beamformer performs complex product sum for n antenna elements, (4 × n) multipliers 201, (2 × n) adders 202, and n antenna elements The outputs of the antenna elements 1I and 2I to nI, which are the I signal outputs of the antenna element 101, and the outputs of the antenna elements 1Q and 2Q to nQ, which are the Q signal outputs of the n antenna elements 101, respectively. Two accumulators 203 for adding and synthesizing and outputting an I signal and a Q signal are provided. The signal output of each antenna element is multiplied by a beam weight 204 by a multiplier 201.
[0047]
Next, the operation of the present embodiment will be described in more detail with reference to FIGS.
[0048]
The RF signals received by the n antenna elements 101 are sent to the radio receiving unit 102 for each antenna element 101. In the radio receiving unit 102, the RF signal is frequency-converted to an intermediate frequency (IF band), amplified by an automatic gain amplifier (not shown), and quadrature-detected into an I / Q channel baseband signal. The signal is converted into a digital signal by an A / D converter (not shown). The output of the wireless receiving unit 102 is sent to the searcher unit 103 and the finger unit 104.
[0049]
In searcher section 103, first, n correlators 105 calculate the code correlation value of the desired wave signal included in the received signal for each antenna element 101. All of the n outputs of the correlator 105 are sent to the searcher section beamformer 106 and weighted by the beam weight 204 in the searcher section beamformer 106.
[0050]
Here, the operation of the searcher unit beamformer 106 will be described with reference to FIG. The searcher unit beamformer 106 multiplies the code correlation value of the desired wave signal input for each antenna element 101 by the beam weight 204 using the multiplier 201 and the adder 202, and then calculates the result for each antenna element 101. The accumulator 203 performs addition synthesis. The output of the correlation value of each antenna element 101 is multiplied by the beam weight 204 in the searcher section beamformer 106 and then synthesized, so that the phase between the elements is corrected. As a result, each of the searcher section beamformers 106 generates one beam, and the output is a reception correlation value output of the beam directed to the arrival direction of the path to be captured.
[0051]
Returning to FIG. 1, the delay profile estimation unit 107 generates a delay profile for each beam from the output of the searcher unit beamformer 106. The path detection circuit 108 searches for the reception timing of the multipath signal from the delay profile, and notifies the reception timing notification signal 116 to each Finger of the finger unit 104.
[0052]
On the other hand, the finger unit 104 performs despreading of the signal obtained from the wireless reception unit 102 using the reception timing notification signal 116 output from the path detection circuit 108. Each Finger is a demodulator 110 (having demodulators for all antenna elements in each Finger), and performs despreading of the path allocated by the searcher unit 103, respectively.
[0053]
The despread signal is input to the finger beamformer 111 and multiplied by the beam weight 204 calculated by the adaptive algorithm in the weight control unit 113 to form a beam equivalently.
[0054]
The output of finger section beamformer 111 is subjected to a channel estimation operation in channel estimation section 112 and output to RAKE combining circuit 114. The RAKE combining circuit 114 collects each Finger output, performs in-phase combining (RAKE combining), and sends it to a decoding circuit (not shown).
[0055]
The error signal required by the adaptive control algorithm in the weight control unit 113 is obtained by multiplying the channel estimation value by the reference signal 115 in the channel estimation unit 112 and then taking the difference from the output of the finger unit beamformer 111. Generated by
[0056]
The weight control unit 113 updates the beam weight 204 so as to minimize the error signal, thereby forming a beam pattern equivalently, and causes the beam to follow the assigned path. An adaptive algorithm such as MMSE is used as an algorithm for determining the weight in the weight control unit 113.
[0057]
In the above embodiment, when the beam weight 204 in the searcher unit beamformer 106 is notified as the weight information 109 from the weight control unit 113 in the finger unit 104, the beam is generated by using the value. However, when there is no notification of the beam weight 204 as the weight information 109 from the finger unit 104 as in the case of the initial synchronization supplement (for example, the searcher unit 103 sends the path reception timing information 116 to the finger unit 104 at least once). In the case where no notification is made, for example, it is assumed that the search is performed in all directions without forming a specific beam by setting all beam weights to the same value.
[0058]
Alternatively, it is possible to form a multi-beam by using the beam weight 204 obtained by the following equation (1). The multi-beam is obtained by dividing the inside of a sector by a plurality of fixed beams, and is configured such that a null point of another beam comes at a peak position of each beam.
[0059]
(Equation 1)

[0060]
However,
m: Beam number (number of beamformers)
n: antenna element number s: beam number t: number of antenna elements.
[0061]
As described above, according to the present invention, an array antenna having a plurality of antenna elements is provided in a radio base station of a mobile communication system using a direct spread CDMA system, and a received signal is multiplied by an arbitrary amplitude weight and a phase weight to be synthesized. This is a receiving device of an adaptive array antenna system that forms a desired beam pattern equivalently by performing the method, and shows a beam pattern generating method in a path detection process (searcher unit) in the receiving device. Therefore, it is possible to easily realize beam generation in the path detection process, and to improve the path detection accuracy which has been a bottleneck in the conventional adaptive array antenna system. This leads to improvement in reception quality of the adaptive array antenna system and increase in communication capacity.
[0062]
By using the present receiving apparatus, it is possible to easily realize beam forming in the searcher unit 103, and it is possible to improve path detection accuracy even in a dynamically changing multipath environment.
[0063]
The present invention is not limited to the number of antenna elements, the number of generated beams, and the number of Fingers (the number of multipaths used for RAKE combining).
[0064]
FIG. 3 is a diagram showing beam directivity characteristics.
[0065]
As an example, a beam pattern having four antenna elements and four beams is shown, and is a diagram illustrating beam directivity characteristics when four beams are formed.
[0066]
The horizontal axis indicates the beam radiation angle of the array antenna, and the vertical axis indicates the antenna gain of the array antenna. The gain of each beam with respect to the beam arrival angle is shown corresponding to each of the beam outputs of the searcher section beamformer 106, ie, beam 1, beam 2, beam 3, and beam 4.
[0067]
Note that, in a CDMA system in which transmission power control is performed so that SIR (signal-to-interference power ratio) after RAKE combining is constant, the present invention can reduce transmission power and also increase communication capacity. Will be.
[0068]
【The invention's effect】
As described above, since the adaptive array antenna receiving apparatus of the present invention can easily realize beam generation in the path detection process, it is possible to improve the path detection accuracy that has been a bottleneck in the adaptive array antenna. It has the effect of being able to.
[0069]
Further, the improvement of the path detection accuracy makes it possible to supplement more multipaths, so that the reception quality after RAKE combining can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing one embodiment of an adaptive array antenna receiving apparatus of the present invention.
FIG. 2 is a detailed block diagram illustrating an example of a beam former of FIG.
FIG. 3 is a diagram showing beam directivity characteristics.
FIG. 4 is a block diagram showing a conventional adaptive array antenna receiving apparatus.
[Explanation of symbols]
Reference Signs List 101 antenna element 102 radio reception unit 103 searcher unit 104 finger unit 105 correlator 106 searcher unit beamformer 107 delay profile estimation unit 108 path detection circuit 109 weight information 110 demodulator 111 finger unit beamformer 112 channel estimation unit 113 weight control Unit 114 RAKE combining circuit 115 reference signal 116 reception timing notification signal 201 multiplier 202 adder 203 accumulator 204 beam weight 401 searcher unit 402 finger unit 405 correlator 407 delay profile estimation unit 408 path detection circuit 409 reception timing notification signal

Claims (11)

An array antenna having a plurality of antenna elements is provided in a radio base station of a mobile communication system using a direct spreading CDMA (Code Division Multiple Access) system, and a received signal is multiplied by an arbitrary amplitude weight and a phase weight to be synthesized. An adaptive array antenna receiving apparatus for forming a desired beam pattern equivalently. In the adaptive array antenna receiver,
n (n is an integer of 1 or more) antenna elements;
N radio receivers for converting RF (Radio Frequency) signals from each of the antenna elements into digital baseband signals;
A searcher unit connected to these radio receiving units and detecting a path position as a reception timing for each beam;
A finger unit that performs despreading at the timing detected by the searcher unit, forms a beam using an MMSE (Minimum Mean Squared Error) adaptive algorithm, and performs maximum ratio combining;
An adaptive array antenna receiving device comprising: The searcher section includes:
a number of correlators corresponding to the n antenna elements, a searcher section beamformer corresponding to the number of beams to be generated, a delay profile estimator for generating a delay profile corresponding to the number of the beams, and the delay 3. The adaptive array antenna receiving apparatus according to claim 2, further comprising a path detection circuit that detects each path from the profile. The finger part is
It has a plurality of Fingers, and each Finger has a demodulator corresponding to the number of the antenna elements, a finger beamformer, a channel estimation unit, a weight control unit, and a RAKE combining circuit,
The weight control unit, as the weight information the optimal amplitude weight and phase weight determined by using the MMSE adaptive algorithm by the difference between the reference signal in the channel estimation unit, not only the finger beamformer, The adaptive array antenna receiving apparatus according to claim 2 or 3, wherein the searcher section beamformer is also notified. The searcher section beamformer,
By multiplying and combining the correlation values of the input signals of all the antenna elements input from the correlator with the weight information of the amplitude weight and the phase weight notified from the weight control unit, in the direction in which the path exists 5. The adaptive array antenna receiving apparatus according to claim 3, wherein a beam is formed equivalently. The delay profile estimator,
A delay profile for each beam is generated from an output of the searcher section beamformer, and the path detection circuit searches a reception timing of a multipath signal from the delay profile, and notifies a reception timing notification signal to the finger section. The adaptive array antenna receiving apparatus according to claim 3, wherein: The finger part is
It has a plurality of Fingers, and each Finger has a demodulator corresponding to the number of the antenna elements, a finger beamformer, a channel estimation unit, a weight control unit, and a RAKE combining circuit,
The demodulator performs despreading of the path of the signal obtained from the radio reception unit using the reception timing notification signal output by the path detection circuit, and the despread signal is input to the finger unit beamformer. 4. The adaptive array antenna receiving apparatus according to claim 2, wherein a beam is equivalently formed by multiplying a beam weight calculated by the MMSE adaptive algorithm in the weight control unit. 8. The adaptive array antenna according to claim 4, wherein an output of the finger beamformer is subjected to a channel estimation operation in the channel estimator, output to the RAKE combining circuit, and in-phase combined. Receiver. The weight control unit includes:
An error signal required by the adaptive control algorithm is generated by multiplying the reference signal and the channel estimation value by the channel estimator, and then taking the difference between the output of the finger beamformer and the error signal. 5. The adaptive array antenna receiving apparatus according to claim 4, wherein a beam pattern is equivalently formed by updating the beam weight so as to minimize the beam weight, and the beam follows the assigned path. The beam weight in the searcher section beamformer generates a beam by using the value when notified as weight information from the weight control section in the finger section, and the weight is transmitted from the finger section at the time of initial synchronization supplementation. 8. When there is no notification of the beam weight as information, all beams are set to the same value to search in all directions without forming a specific beam. Adaptive array antenna receiver. The searcher section beamformer,
In order to perform the complex product sum for the n antenna elements, (4 × n) multipliers, (2 × n) adders, n antenna element nI outputs, and n antennas Two accumulators for adding and synthesizing the element nQ output and outputting an I signal and a Q signal respectively are built in, and the beam weight is multiplied by the multiplier to the nI output and the nQ output, and the correlation value of the antenna element The outputs are combined to correct the phase between the elements to generate one beam each, and the generated output becomes a reception correlation value output of the beam directed to the arrival direction of the path to be captured. The adaptive array antenna receiving device according to claim 10.

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