JP4382998B2 - Radio base system and directivity control method - Google Patents

Description

【００６０】
この無線基地システムから特定の移動端末装置２０への下りの送信信号は、移動端末装置２０で受信され、受信信号ベクトルを、ｈ₁₁，ｈ₁₂，・・・，ｈ_1nで表わすと、移動端末装置２０での受信信号ｙ（ｔ）は、下記の（５）式で表現される。
【００６１】
【数２】

【００６２】
ここで、上述のこの発明の実施の形態により、全体のアンテナ本数ｎが第２のサイクルの仮の参照信号長の１／２以下であって、無線基地システムにおける受信ウェイトベクトルが十分に収束しているものとすると、下記の（６）式が成り立ち、移動端末装置２０に対する下りのアンテナ利得が最大となる。
【００６３】
【数３】

【００６４】
この場合の送信指向性の収束の様子について、図５の（ａ）を参照して説明する。なお、図５において矢印は、移動端末装置から無線基地システムを見た方向を示し、矢印と交差する曲線は、無線基地システムから当該移動端末装置に対する下り方向の指向性を表わしている。
【００６５】
図５の（ａ）において、上記（６）式に示すように無線基地システムからの下り方向のアンテナ利得が最大になれば、指向性のピークが移動端末装置方向に向けられ、送信電波の届く範囲が最大限拡張されることになる。
【００６６】
これに対して、全体のアンテナ本数ｎが参照信号長の１／２を超えて、無線基地システムにおける受信ウェイトベクトルが十分に収束していないものとすると、上記の（７）式が成り立ち、移動端末装置２０に対する下りのアンテナ利得が最大とならない。
【００６７】
この場合の送信指向性の収束の様子について、図５の（ｂ）を参照して説明する。図５の（ｂ）において、上記（７）式に示すように無線基地システムからの下り方向のアンテナ利得が最大にならなければ、指向性のピークが移動端末装置方向からずれることになり、（ａ）のように送信電波の届く範囲が最大限拡張されることはない。
【００６８】
このように、この発明の実施の形態では、第１のサイクルで少ないアンテナ本数で既知の参照信号を用いてとりあえずウェイトベクトルを収束させ、再生された所定の信号長のデータ信号を既知の参照信号に付加して仮の参照信号を形成し、第２のサイクルで仮の参照信号を用いてすべてのアンテナでウェイトベクトルを収束させるように構成したので、既知の参照信号自体を拡張することなく、受信指向性の収束をより容易なものとし、ひいては送信時のアンテナ利得を増大させることができる。
【００６９】
今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
【００７０】
【発明の効果】
以上のように、この発明によれば、既知の参照信号を用いて少数のアンテナでウェイトベクトルを一旦収束させ、再生されたデータ信号の一部を上記既知の参照信号に付加してより長い参照信号を仮に形成し、この仮の参照信号を用いてより多数のアンテナで改めてウェイトベクトルを収束させるように構成している。したがって、既知の参照信号自体の信号長を増大させることなく、より長い仮の参照符号に対応してより多くのアンテナを用いたアダプティブアレイ処理が可能となる。これにより、データのスループットを低下させることなく、より多くのアンテナを使用して無線基地システムの受信指向性を収束させることが可能となり、ひいては送信電波の到達範囲を拡張することができる。
【図面の簡単な説明】
【図１】 この発明の実施の形態の無線基地システムによってソフトウェア的に実行されるアダプティブアレイ処理を機能的に説明する機能ブロック図である。
【図２】 この発明による受信指向性の制御方法の原理を示す模式図である。
【図３】 図１に示したこの発明の実施の形態による無線基地システムのアダプティブアレイ処理を示すフロー図である。
【図４】 この発明による効果を説明するための送信系の機能ブロック図である。
【図５】 この発明による効果を説明するための送信指向性の模式図である。
【図６】 従来の無線基地システムによってソフトウェア的に実行されるアダプティブアレイ処理を機能的に説明する機能ブロック図である。
【符号の説明】
１０ 加算器、１１ 復調回路、１２ 受信ウェイトベクトル計算機、１３ スイッチ回路、１４ 再変調回路、１５ メモリ、１６ カウンタ、１７ 変調回路、１８ コントローラ、Ａ１，Ａ２，・・・，Ａｎ アンテナ、Ｓ１，Ｓ２，・・・，Ｓｎ，Ｂ１，Ｂ２，・・・，Ｂｎ スイッチ回路、ＭＲ１，ＭＲ２，・・・，ＭＲｎ，ＭＴ１，ＭＴ２，・・・，ＭＴｎ 乗算器。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio base system and a directivity control method, and more specifically, in a mobile communication system, a radio base system that extracts a received signal from a specific mobile terminal device by adaptive array processing, and such The present invention relates to a reception directivity control method in a radio base system.
[0002]
[Prior art]
2. Description of the Related Art In recent years, mobile communication systems (for example, Personal Handyphone System: hereinafter referred to as PHS), which are rapidly developing, perform desired communication by means of adaptive array processing in a radio base system when communicating between the radio base system and a mobile terminal device. A method for extracting a received signal from a specific mobile terminal device has been proposed.
[0003]
Adaptive array processing is based on a received signal from a mobile terminal apparatus, calculates a weight vector made up of reception coefficients (weights) for each antenna of the radio base system, and performs adaptive control, thereby allowing a specific mobile terminal apparatus to This is a process for accurately extracting a signal.
[0004]
In the radio base system, a reception weight vector calculator that calculates such a weight vector for each symbol of the reception signal is provided, the reception weight vector calculator includes a complex multiplication sum of the reception signal and the calculated weight vector, A process for converging the weight vector so as to reduce the square of the error with the known reference signal, that is, an adaptive array process for converging the reception directivity from a specific mobile terminal apparatus is executed.
[0005]
In adaptive array processing, such convergence of weight vectors is performed adaptively according to changes in time and propagation characteristics of signal radio waves, and interference components and noise are removed from received signals. The received signal is extracted.
[0006]
FIG. 6 is a functional block diagram for functionally explaining conventional adaptive array processing executed by software by a digital signal processor (DSP) of the radio base system.
[0007]
Referring to FIG. 6, a received signal vector composed of received signals from mobile terminal apparatuses respectively received by a plurality of antennas, for example, n antennas A1, A2,. The circuits S1, S2,..., Sn are switched to the receiving circuit side, and are converted into digital signals by A / D converters (not shown).
[0008]
These digital signals are given to a DSP (not shown) of the radio base system, and are subsequently subjected to adaptive array processing in software according to the functional block diagram shown in FIG.
[0009]
Referring to FIG. 6, the received signal vector switched to the receiving circuit side by switch circuits S1, S2,..., Sn is applied to one input of each of multipliers MR1, MR2,. At the same time, it is given to the reception weight vector calculator 12.
[0010]
The reception weight vector calculator 12 calculates a weight vector composed of a weight for each antenna by an adaptive array algorithm described later, and supplies the weight vector to the other input of each of the multipliers MR1, MR2,. Each of the received signal vectors is subjected to complex multiplication. The adder 10 obtains an array output signal that is the sum of the complex multiplication results.
[0011]
The result of the complex multiplication sum as described above is once demodulated into bit data by the demodulation circuit 11 and then supplied as an array output signal and remodulated by the remodulation circuit 14.
[0012]
The reception weight vector calculator 12 is given a known reference signal d (t) stored in advance in the memory 15 by the switch circuit 13 during the reference signal period defined by the count value of the counter 16, and is based on the adaptive array algorithm. This is used for calculating the weight vector. This reference signal d (t) is a known signal common to all users included in the received signal from the mobile terminal apparatus. For example, in PHS, a preamble (PR) composed of a known bit string in the received signal. And a unique word (UW) section is used.
[0013]
On the other hand, when the end of the reference signal period is detected by the count value of the counter 16, the array output signal remodulated by the remodulation circuit 14 is given to the reception weight vector calculator 12 by the switch circuit 13, and the adaptive array algorithm is used. Used for calculating the weight vector by
The reception weight vector calculator 12 uses an adaptive array algorithm such as an RLS (Recursive Least Squares) algorithm or an SMI (Sample Matrix Inversion) algorithm.
[0014]
Such RLS algorithm and SMI algorithm are well-known techniques in the field of adaptive array processing. For example, “Adaptive signal processing by array antenna” written by Nobuyoshi Kikuma (Science & Technology Publishing), pages 35-49. Since it is described in detail in “Chapter 3 MMSE Adaptive Array”, its description is omitted here.
[0015]
Further, a transmission signal from a transmission signal source (not shown) is modulated by the modulation circuit 17 and applied to one input terminal of each of the multipliers MT1, MT2,..., MTn, and the multipliers MT1, MT2,. The weight vector calculated by the reception weight vector calculator 12 is copied and applied to the other input terminal of MTn.
[0016]
In this way, the transmission signal weighted by the complex multiplication with the weight vector is selected by the switch circuits S1, S2,..., Sn and transmitted via the antennas A1, A2,. .
[0017]
Since signals transmitted through the same antennas A1, A2,..., An as at the time of reception are weighted by weight vectors targeting a specific mobile terminal device in the same manner as received signals, The radio wave signal transmitted from the antenna is skipped with a transmission directivity targeting this specific mobile terminal device.
[0018]
[Problems to be solved by the invention]
By the way, in the conventional radio base system of FIG. 6, signal transmission / reception is performed using n antennas. However, as the number of antennas increases, interference that can be suppressed by adaptive array processing increases, and antenna gain increases. Increases and the range over which the transmitted radio waves reach is expanded. That is, as the number of antennas increases, the performance of adaptive array processing improves.
[0019]
However, in the above-described adaptive array algorithm such as RLS and SMI, in order to converge the weight vector, that is, in order to converge the reception directivity from a specific mobile terminal apparatus, a signal more than twice the number of antennas is required. A long (number of symbols) reference signal is required. In other words, when the signal length of the reference signal is determined in advance, if there are more antennas than 1/2 of the signal length, the weight vector does not converge and the reception directivity also does not converge.
[0020]
For example, in the PHS standard, the reference signal including the preamble and the unique word includes 12 symbols, that is, the signal length is 12. Therefore, the convergence of the weight vector is possible up to the case of using six antennas that are 2/1 of the signal length 12 at the maximum. However, when the number of antennas used exceeds 6, the weight vector can no longer be sufficiently converged.
[0021]
As described above, the reason why the number of antennas that can converge the reception directivity is limited by the signal length of the reference signal is described in, for example, IEICE Transactions, B-II, Vol. J76-B-II, No. 4, April 1993, pages 189-201, Hiroshi Suzuki et al. “Dynamic characteristics analysis for RLS type adaptive equalizer for mobile radio transmission” (particularly 2.3 As described in detail in Section 2 and FIG. 3 and the like, it is well known in the technical field of adaptive array processing, so the description thereof is omitted here.
[0022]
As mentioned above, it is necessary to increase the number of antennas in order to improve the performance of adaptive array processing (so that radio waves can reach far). To that end, refer to the constraints of the adaptive array algorithm described above. It is necessary to increase the signal length of the signal. However, in PHS, for example, according to the standard, the information amount of one frame of a transmission signal composed of a reference signal and a data signal is determined to be 120 bits, and if the reference signal length is increased, the amount of user data that can be transmitted decreases. There is a problem that data throughput is reduced.
[0023]
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a radio base system capable of performing adaptive array processing using more antennas using a reference signal having a limited signal length.
[0024]
Another object of the present invention is to provide a directivity control method capable of converging reception directivity in a radio base system using a reference signal having a limited signal length.
[0025]
Still another object of the present invention is to provide a radio base system and a directivity control method capable of increasing the antenna gain by using a reference signal having a limited signal length and extending the reach of transmission radio waves. is there.
[0026]
[Means for Solving the Problems]
The present invention is a radio base system that transmits and receives signals to and from a plurality of mobile terminal apparatuses using a plurality of antennas, and the signal includes a known reference signal having a first signal length and a second signal length. Are divided into signal sections including data signals. The radio base system receives a reception signal from a first number of antennas that can converge reception directivity by a known reference signal having a first signal length among a plurality of antennas, and a known first signal length. Means for converging the weight vector of a specific mobile terminal device among a plurality of mobile terminal devices based on the reference signal and reproducing a part of the data signal of the second signal length from the specific mobile terminal device And adding the reproduced data signal to the known reference signal of the first signal length to form a reference signal of the third signal length, and converging the reception directivity by the reference signal of the third signal length. Based on the received signals from the second number of antennas and the reference signal having the third signal length, the weight vector of the specific mobile terminal apparatus is converged to obtain the second signal from the specific mobile terminal apparatus. Data signal of signal length And a means for reproducing.
[0027]
Preferably, the radio base system further includes means for converging the transmission directivity of the transmission signal with respect to the specific mobile terminal apparatus by the converged weight vector.
[0028]
More preferably, the second number of antennas is all of the plurality of antennas. More preferably, the number of antennas capable of converging the reception directivity is 2/1 or less of the signal length of the reference signal used for calculating the weight vector.
[0029]
According to another aspect of the present invention, there is provided a radio base system that transmits / receives a signal to / from a plurality of mobile terminal apparatuses using a plurality of antennas, wherein the signal is a known reference signal having a first signal length. And a signal section including a data signal having the second signal length. The radio base system selects a reference signal holding means for holding a reference signal including at least a known reference signal having a first signal length, and a received signal from a designated number of antennas among a plurality of antennas Based on the antenna selection means, the received signal from the antenna selected by the antenna selection means, and the reference signal held in the reference signal holding means, the weight of a specific mobile terminal apparatus among a plurality of mobile terminal apparatuses Weight vector control means for converging the vector, data reproduction means for reproducing a data signal of a second signal length from a specific mobile terminal device based on the converged weight vector, and a reference signal among a plurality of antennas A first book that can converge the weight vector by a known reference signal of the first signal length held in the holding means. The antenna selection means is controlled so as to select the received signal from the second antenna, and a part of the data signal having the second signal length reproduced by the converged weight vector is converted into a known reference signal having the first signal length. In addition, a reference signal having a third signal length is formed and held in the reference signal holding unit, and the weight is determined by the reference signal having the third signal length held in the reference signal holding unit among the plurality of antennas. Control means for controlling the antenna selection means so as to select received signals from the second number of antennas capable of converging the vectors.
[0030]
Preferably, the radio base system further includes transmission directivity control means for converging the transmission directivity of a transmission signal to a specific mobile terminal apparatus by the weight vector converged by the weight vector control means.
[0031]
More preferably, the second number of antennas is all of the plurality of antennas.
More preferably, the number of antennas capable of converging the reception directivity is 2/1 or less of the signal length of the reference signal used for calculating the weight vector.
[0032]
According to still another aspect of the present invention, there is provided a directivity control method in a radio base system that transmits / receives a signal to / from a plurality of mobile terminal apparatuses using a plurality of antennas, wherein the signal has a first signal length. Are divided into signal sections including a known reference signal and a data signal having a second signal length. The directivity control method includes a reception signal from a first number of antennas that can converge reception directivity by a known reference signal having a first signal length among a plurality of antennas, and a first signal length. Based on the known reference signal, the weight vector of a specific mobile terminal device among a plurality of mobile terminal devices is converged to reproduce a part of the data signal having the second signal length from the specific mobile terminal device. Adding the regenerated data signal to the known reference signal of the first signal length to form a reference signal of the third signal length, and converging the reception directivity by the reference signal of the third signal length. Based on the received signals from the second number of antennas and the reference signal having the third signal length, the weight vector of the specific mobile terminal apparatus is converged to obtain the second signal from the specific mobile terminal apparatus. Data signal length of And a step of reproducing the.
[0033]
Preferably, the directivity control method further includes a step of converging the transmission directivity of a transmission signal for a specific mobile terminal apparatus using the converged weight vector.
[0034]
More preferably, the second number of antennas is all of the plurality of antennas.
More preferably, the number of antennas capable of converging the reception directivity is 2/1 or less of the signal length of the reference signal used for calculating the weight vector.
[0035]
Therefore, according to the present invention, the weight vector is temporarily converged with a small number of antennas using a known reference signal, and a part of the reproduced data signal is added to the known reference signal to temporarily add a longer reference signal. Since the weight vector is converged again with a larger number of antennas using this temporary reference signal, more antennas can be used without increasing the signal length of the known reference signal itself. Adaptive array processing can be performed. As a result, the antenna gain can be increased and the reach of the transmission radio wave can be extended without reducing the data throughput.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.
[0037]
FIG. 1 is a functional block diagram functionally illustrating adaptive array processing executed in software by the radio base system according to the embodiment of the present invention. The configuration shown in FIG. 1 is the same as the configuration of the conventional example shown in FIG. 6 except for the following points, and description of common parts will not be repeated.
[0038]
That is, in the configuration shown in FIG. 1, in addition to the configuration of the conventional example shown in FIG. 6, the switch circuits S1, S2,..., Sn and the received weight vector calculator 12 are selectively connected / disconnected. Switch circuits B1, B2,..., Bn and a controller 18 for controlling the selection operation of these switch circuits are provided.
[0039]
Further, a part of the signal remodulated by the remodulation circuit 14 is connected so that it can be held in the memory 15.
[0040]
FIG. 2 is a schematic diagram showing the principle of the reception directivity control method according to the present invention. The principle of the reception directivity control method according to the present invention will be described below with reference to FIG.
[0041]
According to the present invention, first, as shown in FIG. 2A, reception of one frame including at least a known reference signal (PR + UW), a data signal (DATA), and an error identification code (for example, CRC). For a signal, a weight vector with a number of antennas (for example, the number corresponding to 1/2 of the signal length of the reference signal) within the period of the known reference signal (PR + UW) that can converge the reception directivity with the signal length. That is, the reception directivity is once converged (hereinafter referred to as the first cycle).
[0042]
In this state, as shown in FIG. 2B, in the data signal period after the reference signal period (the period indicated by the arrow B), the array output signal is synthesized from the data signals corresponding to several symbols (the period indicated by the arrow A). Then, a signal obtained by demodulating and remodulating the combined array output signal is added to a known reference signal (PR + UW) to temporarily form a longer reference signal (signal period indicated by arrow B + A in FIG. 2).
[0043]
In this provisionally longer reference signal period, the number of antennas (corresponding to 1/2 of the signal length B + A) whose reception directivity can be converged with the signal length, for example, all the antennas of the radio base system, are renewed. That is, the reception directivity is converged (hereinafter referred to as the second cycle).
[0044]
Next, FIG. 3 is a flowchart showing adaptive array processing of the radio base system according to the embodiment of the present invention shown in FIG. The operation of the radio base system according to the embodiment of the present invention will be described below with reference to FIGS.
[0045]
First, in step S1 of FIG. 3, an antenna to be used in the first cycle is selected. As described above, the maximum number of antennas that can be used in the first cycle is ½ of the signal length of the known reference signal (PR + UW).
[0046]
For example, the following three types of methods are conceivable as a method of selecting the number of antennas of reference signal length / 2 among all (n) antennas of the radio base system. First, as a first method, among the randomly numbered n antennas, the first antenna to the (reference signal length / 2) -th antenna are mechanically selected. That is, this is a method of randomly selecting (reference signal length / 2) antennas from n antennas.
[0047]
As a second method, a reception level measuring device (not shown) is provided for all n antennas, and from the n antennas, the antenna with the higher reception level (reference signal length / 2) is selected. It is a method to do.
[0048]
The third method is a method of selecting n antennas (reference signal length / 2) that are arranged as far as possible from each other among n antennas. Note that these three methods are merely examples of antenna selection methods, and any method of selecting (antenna length of reference signal / 2) antennas from all n antennas can be used.
[0049]
The controller 18 shown in the functional block diagram of FIG. 1 is configured by a DSP (not shown), and n antennas A1, A2,..., An by any of the methods listed in step S1 of FIG. A control signal for controlling connection / disconnection of the switch circuits B1, B2,..., Bn is generated so as to select a signal received by the antennas (reference signal length / 2) from the signals received in (1). . For example, if the known reference signal length is 12 symbols, reception signals from a maximum of 6 antennas can be selected.
[0050]
In step S1, when reception signals from (reference signal length / 2) antennas are selected, in step S2, the period of a known reference signal (PR + UW) defined by the counter 16 ((a) in FIG. 2). Reference), a known reference signal (PR + UW) is read from the memory 15 and input to the reception weight vector calculator 12 via the switch circuit 13 to calculate a reception weight vector.
[0051]
When the counter 16 detects the end of the reference signal period, the process proceeds to step S3, and the reception weight vector calculator 12 continues to (b) of FIG. 2 based on the reception signals from the (reference signal length / 2) antennas. As shown, a weight vector is calculated in a data signal period of several symbols (period of arrow A) after the reference signal period (period of arrow B).
[0052]
Next, in step S4, an array output signal is synthesized from the data signals for several symbols, for example, 4 symbols. The combined array output signal is once demodulated into bit data by the demodulation circuit 11, then remodulated by the remodulation circuit 14, and given to the memory 15.
[0053]
As a result, for example, a data signal for 4 symbols is added to a known reference signal (PR + UW) having a signal length of 12 symbols, for example, and a longer reference signal of 16 symbols, for example, is temporarily formed (indicated by arrow B + A in FIG. 2). Signal period shown).
[0054]
Next, in step S5, the controller 18 selects the switching circuits B1, B2 so as to select signals received by all of the n antennas A1, A2,..., An to be used in the second cycle. , ..., generates a control signal for controlling connection / disconnection of Bn. For example, if the provisional reference signal is 16 symbols, reception signals from a maximum of 8 antennas can be selected.
[0055]
In step S5, when reception signals from n antennas are selected, this is read from the memory 15 over the period of the above-described provisional reference signal defined by the counter 16 (period B + A in FIG. 2B). A temporary reference signal is read and input to the reception weight vector calculator 12 via the switch circuit 13, and a reception weight vector is calculated.
[0056]
Thereafter, in step S6, normal adaptive array processing is continued.
[0057]
Next, FIG. 4 and FIG. 5 are a partial functional block diagram and a schematic diagram of transmission directivity for explaining the effects of the embodiment of the present invention. With reference to FIG. 4 and FIG. 5, even if the number of antennas increases, if an ideal weight vector can be calculated according to the present invention, a sufficient array gain can be obtained. The principle of improving the transmission directivity and the radio wave reachability will be described in detail.
[0058]
FIG. 4 is a functional block diagram for explaining the functions of the transmission system of the radio base system shown in FIG. 1. The transmission signal S (t) is modulated by the modulation circuit 17 and then transmitted by multipliers MT1, It is given to one input of each of MT2,. A weight vector targeting a specific mobile terminal device, which is calculated by the reception weight vector calculator 12 of FIG. 1, is copied and applied to these multipliers. The following (1) A signal represented by the equations (4) to (4) is output and applied to the antennas A1, A2,.
[0059]
[Expression 1]

[0060]
A downlink transmission signal from this radio base system to a specific mobile terminal apparatus 20 is received by the mobile terminal apparatus 20, and a received signal vector is expressed as h. ₁₁ , H ₁₂ , ..., h _1n In other words, the received signal y (t) at the mobile terminal device 20 is expressed by the following equation (5).
[0061]
[Expression 2]

[0062]
Here, according to the above-described embodiment of the present invention, the total number n of antennas is ½ or less of the provisional reference signal length of the second cycle, and the reception weight vector in the radio base system is sufficiently converged. (6) below holds, and the downlink antenna gain for the mobile terminal apparatus 20 is maximized.
[0063]
[Equation 3]

[0064]
The state of convergence of the transmission directivity in this case will be described with reference to FIG. In FIG. 5, an arrow indicates a direction when the radio base system is viewed from the mobile terminal apparatus, and a curve intersecting the arrow indicates directivity in the downlink direction from the radio base system to the mobile terminal apparatus.
[0065]
In FIG. 5A, when the antenna gain in the downlink direction from the radio base system is maximized as shown in the above equation (6), the directivity peak is directed toward the mobile terminal apparatus, and the transmitted radio wave reaches. The range will be expanded as much as possible.
[0066]
On the other hand, if the total number n of antennas exceeds 1/2 of the reference signal length and the reception weight vector in the radio base system is not sufficiently converged, the above equation (7) is established, and the movement The downlink antenna gain for the terminal device 20 is not maximized.
[0067]
The state of convergence of the transmission directivity in this case will be described with reference to FIG. In FIG. 5B, if the antenna gain in the downlink direction from the radio base system does not become maximum as shown in the above equation (7), the directivity peak is shifted from the mobile terminal device direction. As in a), the reach of the transmission radio wave is not expanded to the maximum extent.
[0068]
As described above, according to the embodiment of the present invention, the weight vector is first converged using a known reference signal with a small number of antennas in the first cycle, and the reproduced data signal having a predetermined signal length is used as the known reference signal. In order to converge the weight vector at all antennas using the temporary reference signal in the second cycle without extending the known reference signal itself, The reception directivity can be more easily converged, and the antenna gain during transmission can be increased.
[0069]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0070]
【The invention's effect】
As described above, according to the present invention, the weight vector is once converged with a small number of antennas using a known reference signal, and a part of the reproduced data signal is added to the known reference signal to obtain a longer reference. A signal is temporarily formed, and the weight vector is converged again by a larger number of antennas using the temporary reference signal. Therefore, adaptive array processing using more antennas corresponding to a longer temporary reference code can be performed without increasing the signal length of the known reference signal itself. As a result, the reception directivity of the radio base system can be converged using more antennas without reducing the data throughput, and as a result, the reach of the transmission radio wave can be extended.
[Brief description of the drawings]
FIG. 1 is a functional block diagram functionally explaining an adaptive array process executed by software by a radio base system according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing the principle of a reception directivity control method according to the present invention.
FIG. 3 is a flowchart showing adaptive array processing of the radio base system according to the embodiment of the present invention shown in FIG. 1;
FIG. 4 is a functional block diagram of a transmission system for explaining the effect of the present invention.
FIG. 5 is a schematic diagram of transmission directivity for explaining the effect of the present invention.
FIG. 6 is a functional block diagram functionally illustrating adaptive array processing executed in software by a conventional radio base system.
[Explanation of symbols]
10 adder, 11 demodulation circuit, 12 reception weight vector calculator, 13 switch circuit, 14 remodulation circuit, 15 memory, 16 counter, 17 modulation circuit, 18 controller, A1, A2,..., An antenna, S1, S2 ,..., Sn, B1, B2,..., Bn switch circuit, MR1, MR2,..., MRn, MT1, MT2,.

Claims (12)

A radio base system that transmits and receives signals to and from a plurality of mobile terminal apparatuses using a plurality of antennas, wherein the signal includes a known reference signal having a first signal length and a data signal having a second signal length. And is divided into signal sections including
Among the plurality of antennas, received signals from a first number of antennas whose reception directivity can be converged by a known reference signal of the first signal length, and a known reference of the first signal length. Based on the signal, the weight vector of a specific mobile terminal device among the plurality of mobile terminal devices is converged to reproduce a part of the data signal of the second signal length from the specific mobile terminal device Means,
The reproduced data signal is added to the known reference signal of the first signal length to form a reference signal of the third signal length, and reception directivity is converged by the reference signal of the third signal length. Based on the received signals from the second number of antennas and the reference signal having the third signal length, the weight vector of the specific mobile terminal apparatus is converged, and the specific mobile terminal apparatus And a means for reproducing the data signal having the second signal length. The radio base system according to claim 1, further comprising means for converging a transmission directivity of a transmission signal with respect to the specific mobile terminal apparatus by the converged weight vector. The radio base system according to claim 1 or 2, wherein the second number of antennas is all of the plurality of antennas. The radio base system according to any one of claims 1 to 3, wherein the number of antennas capable of converging reception directivity is a number equal to or less than 2/1 of a signal length of a reference signal used for calculating a weight vector. A radio base system that transmits and receives signals to and from a plurality of mobile terminal apparatuses using a plurality of antennas, wherein the signal includes a known reference signal having a first signal length and a data signal having a second signal length. And is divided into signal sections including
Reference signal holding means for holding a reference signal, comprising at least a known reference signal of the first signal length;
An antenna selection means for selecting a reception signal from a designated number of antennas among the plurality of antennas;
Based on the received signal from the antenna selected by the antenna selection means and the reference signal held in the reference signal holding means, the weight vector of a specific mobile terminal apparatus among the plurality of mobile terminal apparatuses is converged Weight vector control means,
Data reproducing means for reproducing the data signal of the second signal length from the specific mobile terminal device based on the converged weight vector;
Among the plurality of antennas, a reception signal from a first number of antennas that can converge a weight vector by a known reference signal having the first signal length held in the reference signal holding unit is selected. The antenna selecting means is controlled to add a part of the data signal of the second signal length reproduced by the converged weight vector to the known reference signal of the first signal length to add a third A reference signal having a signal length of the third signal length is held in the reference signal holding unit, and a weight vector is determined by the third signal length reference signal held in the reference signal holding unit among the plurality of antennas. And a control means for controlling the antenna selection means so as to select received signals from the second number of antennas capable of converging. Temu. The radio base system according to claim 5, further comprising transmission directivity control means for converging transmission directivity of a transmission signal to the specific mobile terminal apparatus using the weight vector converged by the weight vector control means. The radio base system according to claim 5 or 6, wherein the second number of antennas is all of the plurality of antennas. The radio base system according to any one of claims 5 to 7, wherein the number of antennas capable of converging reception directivity is a number equal to or less than 2/1 of a signal length of a reference signal used for calculating a weight vector. A directivity control method in a radio base system for transmitting / receiving signals to / from a plurality of mobile terminal apparatuses using a plurality of antennas, wherein the signal includes a known reference signal having a first signal length, a second reference signal, It is divided into signal sections including data signals of signal length,
Among the plurality of antennas, received signals from a first number of antennas whose reception directivity can be converged by a known reference signal of the first signal length, and a known reference of the first signal length. Based on the signal, the weight vector of a specific mobile terminal device among the plurality of mobile terminal devices is converged to reproduce a part of the data signal of the second signal length from the specific mobile terminal device Steps,
The reproduced data signal is added to the known reference signal of the first signal length to form a reference signal of the third signal length, and reception directivity is converged by the reference signal of the third signal length. Based on the received signals from the second number of antennas and the reference signal having the third signal length, the weight vector of the specific mobile terminal apparatus is converged, and the specific mobile terminal apparatus Regenerating the data signal of the second signal length. The method according to claim 9, further comprising: converging transmission directivity of a transmission signal with respect to the specific mobile terminal device by the converged weight vector. The method according to claim 9 or 10, wherein the second number of antennas is all of the plurality of antennas. The method according to any one of claims 9 to 11, wherein the number of antennas capable of converging reception directivity is a number equal to or less than 2/1 of a signal length of a reference signal used for calculating a weight vector.

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