JP5230779B2 - Wireless communication apparatus and wireless communication method - Google Patents

Description

  The present invention relates to a multi-carrier transmission type digital radio communication system using a plurality of subcarriers having different frequencies, and a radio communication apparatus and radio having an array antenna having a direction estimation means for an incoming path and a directivity control means based thereon. It relates to a communication method.

  Signals received by the wireless communication device are subject to interference due to various signals, resulting in degradation of reception quality. An adaptive array antenna (adaptive antenna) is known as a technique for suppressing this interference and receiving only a signal arriving from a desired direction. In an adaptive array antenna, a signal arriving from a desired direction is adjusted by adjusting a weighting coefficient to be multiplied to a received signal (hereinafter, this weighting coefficient is referred to as “weight”) and adjusting an amplitude and a phase applied to the received signal. Only can be received strongly.

  In recent years, there has been a growing demand for higher capacity and higher speed of wireless communication, and multipath resistance and anti-fading countermeasures have become major issues for its realization. Multi-carrier transmission, in which a wide band transmission is performed in parallel by a plurality of narrow-band subcarriers, is one approach for solving the problem. In particular, orthogonal frequency division multiplexing (OFDM) transmission is a digital terrestrial signal. It is used in broadcasting and broadband wireless access systems.

  By using an adaptive array antenna in a multicarrier transmission system, the characteristics of both can be further utilized, and multipath resistance and fading resistance can be further improved.

  Although a detailed description of the configuration is omitted, in a multi-carrier transmission system, as a conventional radio apparatus having an adaptive array antenna, by calculating an antenna weight for each subcarrier, a specific band (= total communication band / Even when the center frequency of the entire communication band is large, a uniform antenna directional beam can be obtained in the entire communication band of the OFDM transmission method, enabling transmission and reception that is less susceptible to interference waves such as multipath within the entire communication band. (For example, refer to Patent Document 1).

JP-A-11-205026

  However, in the conventional adaptive antenna wireless communication apparatus, direction estimation is performed for each subcarrier and the array weight is calculated. Therefore, when affected by frequency selective fading, it is sufficient for subcarrier signals with low received power. There arises a problem that direction estimation cannot be performed with high accuracy. Further, when the number of subcarriers is large, there is a problem that the circuit scale increases when the direction is estimated for each subcarrier.

  An adaptive antenna wireless communication apparatus according to the present invention includes a transmission weight generation unit that generates one transmission array weight for forming a transmission directional beam for each divided band obtained by dividing a communication band for multicarrier transmission, and the above division Multiplying the transmission subcarrier signal by the transmission array weight generated for each band to transmit a weighted transmission signal, and transmitting the weighted transmission signal And an array antenna composed of a plurality of antenna elements.

  According to the present invention, by generating an array weight for each divided band obtained by dividing a communication band, it is possible to suppress deterioration in arrival direction estimation accuracy even when a subcarrier signal with low received power exists in the divided band. it can.

1 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing a detailed configuration of a divided band direction estimation unit in the first embodiment. The figure which shows the spatial profile calculation result in the division | segmentation band direction estimation part in Embodiment 1. FIG. FIG. 11 is a block diagram showing another configuration of the divided band direction estimation unit in the first embodiment. FIG. 3 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 2 of the present invention. Block diagram showing a configuration of a wireless communication apparatus according to Embodiment 3 of the present invention FIG. 9 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 4 of the present invention.

The radio communication apparatus according to the present invention includes an array antenna that receives a signal transmitted by multicarrier and a plurality of subcarrier signals included in the subcarrier signal group that belong to the divided band for each divided band obtained by dividing the communication band used for multicarrier transmission. A reception weight generation unit that generates one reception array weight for forming a reception directional beam by using a subcarrier signal, and the reception array weight generated for each of the divided bands is set as the received signal weight. Among them, a subcarrier reception directivity forming unit that generates a weighted subcarrier signal by multiplying the subcarrier signal belonging to the divided band, and a decoding unit that decodes the weighted subcarrier signal It is characterized by comprising.
The radio communication apparatus of the present invention includes an array antenna that receives a signal transmitted by multicarrier and a subcarrier signal group that belongs to the divided band for each divided band obtained by dividing the communication band used for the multicarrier transmission. A reception weight generator for generating a reception array weight for forming a plurality of reception directional beams using the plurality of subcarrier signals, and the reception array weight generated for each of the divided bands. Among the received signals, a subcarrier reception directivity forming unit that generates a plurality of weighted subcarrier signals by multiplying the subcarrier signals belonging to the divided band, and the plurality of weighted subcarrier signals. And a decoding unit for decoding the carrier signal.
The wireless communication method of the present invention receives a signal transmitted by multicarrier and, for each divided band obtained by dividing a communication band used for the multicarrier transmission, a plurality of subcarriers included in a subcarrier signal group belonging to the divided band One reception array weight for forming a reception directional beam is generated using a signal, and the reception array weight generated for each division band belongs to the division band among the received signals. By multiplying the subcarrier signal, a weighted subcarrier signal is generated, and the weighted subcarrier signal is decoded.
In addition, the wireless communication method of the present invention receives a signal transmitted by multicarrier and, for each divided band obtained by dividing a communication band used for the multicarrier transmission, includes a plurality of subcarrier signal groups belonging to the divided band. Using a subcarrier signal, a reception array weight for forming a plurality of reception directional beams is generated, and the reception array weight generated for each division band is used as the division band in the received signal. By multiplying the subcarrier signals belonging to, a transmission signal with a plurality of weights is formed, and the plurality of weighted subcarrier signals are decoded.
Also, the radio communication method of the present invention receives a multicarrier-transmitted signal, generates one receive array weight, and multiplies the received signal by the receive array weight, thereby performing weighting. Subcarrier signals are generated, and the weighted subcarrier signals are decoded.

  According to the present invention, when directional transmission is performed, the angular spread is detected based on the spatial spectrum for each divided band or the entire communication band. When transmission directivity control is performed based on the average direction of arrival and the angular spread is large, 1) directivity transmission control in the direction that gives the maximum received power in the direction estimation result for each divided band, or 2) division Directional transmission control is performed in a direction in which a predetermined number of higher received power is given in the direction estimation result for each band. As a result, directional transmission can be performed in the direction of the arrival path at the time of reception, interference with other users can be effectively reduced, communication quality can be improved, and system capacity can be improved.

  Further, according to the present invention, in an adaptive antenna radio communication apparatus equipped with an array antenna, when performing a wideband multicarrier transmission scheme, it is used that a spatial spectrum correlation between adjacent subcarrier signals is high. Thus, by estimating the average direction of arrival of the subcarrier signal group belonging to the divided band obtained by dividing the communication band, even if there is a subcarrier with low received power, the subcarrier signal group to which the subcarrier signal group belongs By estimating the arrival direction, it is possible to suppress degradation of estimation accuracy, and it is possible to improve reception quality by performing directional reception using a robust direction estimation result. In addition, when directivity transmission is performed, it is possible to reduce inter-user interference and communication quality by switching the directivity transmission method according to the angular spread by detecting the angular spread based on the spatial profile in the entire communication band. Can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an adaptive antenna radio communication apparatus according to Embodiment 1 of the present invention. The adaptive antenna wireless communication apparatus shown in FIG. 1 uses the array antenna 1 composed of a plurality of Na antenna elements 1-1 to Na and the high-frequency signal s1-k received by the k-th antenna element 1-k as a frequency. After the conversion, a demultiplexer 2-k (where k = 1 to Na) for demultiplexing a plurality of Ns subcarrier signals f1-k into fNs-k, among the divided bands obtained by dividing the communication band into Nd pieces, The direction estimation results in the subband direction estimation unit 4-m and the mth subband direction estimation unit 4-m that perform direction-of-arrival estimation using subcarrier signal groups belonging to the mth subband 3-m. Based on the array weights generated by the divided band array weight generating unit 5-m and the divided band array weight generating unit 5-m that generates the array weights based on the subcarrier signal group belonging to the mth divided band 3-m Sub-camera for directivity formation And a demodulating unit 7 for performing data demodulation by use A directivity forming section 6-m, each sub-carrier signal received directional. However, m = 1,. . . , Nd. FIG. 1 shows a configuration example in the case where the number of antenna elements Na = 2, the number of subcarriers Ns = 4, and the number of divided bands Nd = 2.

  The operation will be described below with reference to FIG. First, the high frequency signals s1-1 to Na transmitted by the multicarrier system are received by the antenna elements 1-1 to Na constituting the array antenna 1, respectively. Among these, the high-frequency signal s1-k received by the k-th antenna element 1-k is sequentially subjected to high-frequency amplification and frequency conversion by the duplexer 2-k, and is used for multicarrier transmission. Carrier signals f1-k, f2-k,. . . , FNs-k are extracted. Here, the entire communication band is divided into Nd divided bands, and the subcarrier signal group belonging to the mth divided band 3-m is divided into a divided band direction estimation unit 4-m and a subcarrier directivity forming unit. 6-m. The number of subbands Nd can be set as a natural number in the range of the total number of subcarriers Ns ≧ Nd> 1. Further, the number of subcarriers belonging to the subcarrier signal group belonging to each divided band 3 is not necessarily equal, but in the following description, the same number of subcarriers Nc (= Ns / Nd) will be described.

  Using the subcarrier signal group belonging to the m-th divided band 3-m, the divided band direction estimation unit 4-m performs direction-of-arrival estimation. FIG. 2 shows a detailed configuration diagram of the divided band direction estimation unit 4. In FIG. 2, the divided band direction estimation unit 4 generates a pilot signal generation unit 20 that generates a known pilot signal embedded in each subcarrier signal, and receives each subcarrier signal and the generated pilot signal. The pilot signal correlation calculation unit 21 calculates a correlation value, the correlation matrix generation unit 22 generates a correlation matrix based on the pilot signal correlation value, and the spatial profile calculation unit 23 calculates a spatial profile based on the correlation matrix. Yes. The operation will be described below with reference to FIG. FIG. 2 shows an example of the divided band direction estimation unit 4-1 in the first divided band 3-1, when the number of antenna elements Na = 2 and the number of subcarriers Nc = 2 in the divided band.

The pilot signal generation unit 20 generates a known signal (hereinafter referred to as pilot signal) embedded in advance in the subcarrier signal. The pilot signal correlation calculation unit 21 performs a correlation calculation between the generated pilot signal and the received pilot symbol of the subcarrier signal. Here, the pilot signal is r (s). However, s = 1 to Np, and Np is the number of symbols of the pilot signal. The k-th antenna element 1-k received by the m-th divided band 3-m belonging to the n-th sub-carrier signal fn-k _(t 0) (Note, t ₀ represents the path arrival timing. ), The pilot signal correlation calculation unit 21- _nk performs the correlation calculation shown in (Equation 1) to calculate the pilot correlation value h _nk . However, No indicates the number of oversamples for the symbol, and * indicates the complex conjugate. Hereinafter, pilot correlation values h _nk are calculated for subcarrier signal groups (n = 1 to Nc) belonging to the mth subband 3-m received by all antenna elements (k = 1 to Na).

相関行列生成部２２は、パイロット信号相関演算部２１において算出されたパイロット相関値ｈｎｋを用いて、（数２）で示される相関ベクトルＶｎを用いて、（数３）にされる相関行列Ｒを算出する。ただし、ｎ＝１〜Ｎｓ、ｋ＝１〜Ｎａ、Ｔはベクトル転置を示す。

The correlation matrix generation unit 22 uses the pilot correlation value hnk calculated by the pilot signal correlation calculation unit 21 and uses the correlation vector Vn expressed by (Equation 2) to generate the correlation matrix R expressed by (Equation 3). calculate. However, n = 1 to Ns, k = 1 to Na, and T represent vector transposition.

  The spatial profile calculation unit 23 performs direction estimation using the correlation matrix R generated by the correlation matrix generation unit 22. Although many direction estimation algorithms have been proposed, the operation in the case of applying an algorithm that generates a spatial profile based on the Fourier method and detects the peak direction to obtain an arrival direction estimation value will be described below.

  The spatial profile calculation unit 23 calculates a spatial profile by varying the parameter θ in the arrival direction estimation evaluation function F (θ) shown in (Equation 4) by a predetermined angle step Δθ, and in order of increasing peak level of the spatial profile. A predetermined number M (M ≧ 1) of peak directions are detected and used as arrival direction estimation values. However, a (θ) is a direction vector determined by the element arrangement of the array antenna 1, and can be expressed as (Equation 5), for example, in the case of a uniform linear array with an element interval d. Here, λ is the wavelength of the center frequency in the divided band 3-m in the carrier wave band, and θ is the direction of 0 ° in the normal direction of the linear array. H represents complex conjugate transposition.

図３はアレー素子数Ｎａ＝８、サブキャリア信号群のサブキャリア数Ｎｃ＝２の場合の空間プロファイル算出結果を示す。図３（ａ）はサブキャリア１の到来角度θ_１＝２０°、サブキャリア２の到来角度θ_２＝−２０°の結果であり、図３（ｂ）はサブキャリア１の到来角度θ_１＝５°、サブキャリア２の到来角度θ_２＝−５°の結果である。（数４）で示す到来方向推定はビームフォーマ法を用いており、アレーアンテナ１のビーム幅より、到来パス間隔が十分離れている場合はそれぞれのパス方向に対するピークを検出することができる（図３ａ）。また、複数パスの到来角度が近接している場合（図３ｂ）、パス数に比べ少ないピーク数をもつ空間プロファイルが得られる。この場合のピーク方向は、複数パスの合成電力が最大となる方向となる。

FIG. 3 shows a spatial profile calculation result when the number of array elements Na = 8 and the number of subcarriers Nc = 2 in the subcarrier signal group. 3A shows the results of the arrival angle θ ₁ = 20 ° of the subcarrier _{1 and} the arrival angle θ ₂ = −20 ° of the subcarrier 2, and FIG. 3B shows the arrival angle θ ₁ = of the subcarrier _1. This is a result of 5 ° and the arrival angle θ 2 of the subcarrier ₂ = −5 °. The arrival direction estimation expressed by (Equation 4) uses the beamformer method, and when the arrival path interval is sufficiently away from the beam width of the array antenna 1, the peak for each path direction can be detected (see FIG. 4). 3a). Further, when the arrival angles of a plurality of paths are close (FIG. 3b), a spatial profile having a smaller number of peaks than the number of paths can be obtained. In this case, the peak direction is the direction in which the combined power of a plurality of paths is maximized.

The subband array weight generation unit 5-m applies the maximum peak direction or the predetermined number of direction estimation results in the subband direction estimation unit 4-m to the subcarrier signal group belonging to the mth subband 3-m. An array weight for directing the main beam in a plurality of peak directions is generated, and the subcarrier directivity forming unit 6-m outputs a signal obtained by multiplying and combining the generated array weight by each subcarrier signal. The array weight is generated in consideration of the wavelength λm of the center frequency of each divided band 3-m in the radio frequency band. This is particularly effective when the ratio band is large. For example, in the case of an equally spaced linear array with element spacing d, the array weight Wm in the m-th divided band 3-m can be expressed as (Equation 6). Here, θ ₀ is a direction estimation result. The normal direction of the linear array is set to 0 °.

復調部７は、すべての分割帯域３での指向性形成部６により指向性受信された各サブキャリア信号を用いて、復調動作を行いデータ受信する。

The demodulator 7 uses the subcarrier signals directionally received by the directivity generator 6 in all the divided bands 3 to perform a demodulation operation and receive data.

  In the present embodiment, by generating a correlation matrix R that combines the correlation vectors Vn obtained from the subcarrier signals belonging to the subcarrier signal group belonging to the divided band 3, and performing arrival direction estimation using the correlation matrix R, It is possible to estimate the average direction of arrival of the subcarrier signal group within the divided band. As a result, when the frequency interval between subcarrier signals is sufficiently narrow, the spatial correlation characteristics between adjacent subcarrier signals are relatively high, and even if the received power per subcarrier signal is small, those subcarriers Since direction estimation is performed after in-phase synthesis of signals, there is an effect that the arrival direction estimation accuracy can be ensured. When the frequency interval between the subcarrier signals is sufficiently wide, there is an effect of stabilizing the direction estimation accuracy due to the frequency diversity effect.

Note that the correlation matrix generation unit 22 may use the correlation vector z shown in (Expression 7) instead of the correlation matrix R shown in (Expression 3). Instead, the spatial profile shown in (Equation 8) is calculated and the peak level is detected to obtain the estimated arrival direction. Here, V _{n, m} represents the mth element of the correlation vector Vn.

なお、各サブキャリア信号が時間軸方向に拡散されるマルチキャリア直接拡散符号分割多重（ＭＣ／ＤＳ−ＣＤＭＡ）方式を用いて伝送される場合、分割帯域方向推定部４はサブキャリア信号における到来時刻の異なるマルチパス信号を取り出し、それらの複数パスの方向推定を行う構成でも良く、図４にその構成例を示す。図４における分割帯域方向推定部４ｂの分割帯域方向推定部４の別な構成を示す図である。図４において分割帯域方向推定部４ｂは、各サブキャリア信号に埋め込まれた予め既知であるパイロット信号を生成するパイロット信号生成部２０、サブキャリア信号毎に複数の到来パスタイミングを検出するパスサーチ部３０、検出された複数の到来パスタイミング毎に受信されたサブキャリア信号と生成されたパイロット信号との相互相関値を算出するパイロット信号演算部３１、それらのパイロット信号相関値を基に相関行列を生成する相関行列生成部３２と、生成された相関行列を用いて空間的な空間プロファイルを演算する空間プロファイル演算部３３とから構成されている。以下、図４を用いてその動作説明を行う。なお、図４はアンテナ素子数Ｎａ＝２、分割帯域内のサブキャリア数Ｎｃ＝２の場合の例を示している。

When each subcarrier signal is transmitted using a multicarrier direct spreading code division multiplexing (MC / DS-CDMA) method in which each subcarrier signal is spread in the time axis direction, the division band direction estimation unit 4 receives the arrival time in the subcarrier signal. A configuration may be adopted in which multipath signals having different paths are taken out and the directions of those multiple paths are estimated. FIG. 4 shows an example of the configuration. It is a figure which shows another structure of the division | segmentation band direction estimation part 4 of the division | segmentation band direction estimation part 4b in FIG. In FIG. 4, a divided band direction estimation unit 4b includes a pilot signal generation unit 20 that generates a known pilot signal embedded in each subcarrier signal, and a path search unit that detects a plurality of arrival path timings for each subcarrier signal. 30, a pilot signal calculation unit 31 that calculates a cross-correlation value between a subcarrier signal received for each of a plurality of detected arrival path timings and a generated pilot signal, and a correlation matrix based on the pilot signal correlation value A correlation matrix generation unit 32 to be generated and a spatial profile calculation unit 33 to calculate a spatial space profile using the generated correlation matrix. The operation will be described below with reference to FIG. FIG. 4 shows an example in which the number of antenna elements Na = 2 and the number of subcarriers Nc = 2 in the divided band.

The path search units 30-1 to Ns generate a delay profile using the pilot signal embedded in the subcarrier signal, and detect the peak timing of the higher received power as the path timing. Here, the number of detected reception path timings in the path search unit 30-n for the nth subcarrier signal of a certain subcarrier signal group is Ln. However, n = 1 to Nc. The pilot signal correlation value h _nk (t _j ) at the j-th path timing t _j for the n-th subcarrier signal fn-k received by the k-th antenna element 1 -k is ( _Equation 9). Can be represented. Here, the pilot signal is r (s). However, s = 1 to Np, and Np is the number of symbols of the pilot signal.

なお、遅延プロファイルは、１）各アンテナ素子１―１〜Ｎで得られたパイロット信号相関値ｈ_ｎｋ（ｔ_ｊ）の絶対値あるいは２乗を同じタイミング毎に合成する方法、あるいは、２）指向性ビーム形成する重みを同じタイミングのパイロット相関値ｈ_ｎｋ（ｔ_ｊ）に乗算後、加算し、その絶対値あるいは２乗をとることで複数の遅延プロファイルを生成する方法、さらにはそれらを合成する方法により生成する。また、遅延プロファイルは、複数フレーム間にわたり平均化することで、ノイズ成分を抑圧することができる。

The delay profile is 1) a method of synthesizing the absolute value or square of the pilot signal correlation values h _nk (t _j ) obtained by the antenna elements 1-1 to N at the same timing, or 2) directivity. A method of generating a plurality of delay profiles by multiplying the pilot correlation values h _nk (t _j ) of the same timing by the weights for forming the beam and adding them, and taking their absolute values or squares, and further combining them Generate by the method. In addition, the noise profile can be suppressed by averaging the delay profile over a plurality of frames.

The correlation matrix generation unit 32 uses the pilot correlation value h _nk (t _j ) calculated by the pilot signal correlation calculation unit 31 and the correlation vector Vn (t _j ) represented by (Equation 10) to calculate (Equation 11). The correlation matrix R shown is calculated. Here, n = 1 to Ns, k = 1 to Na, and H represent vector complex conjugate transpose.

空間プロファイル演算部３３は、相関行列生成部３２により生成された相関行列Ｒを用いて、（数４）に示す空間プロファイルを算出し方向推定を行う。

The spatial profile calculator 33 calculates the spatial profile shown in (Equation 4) using the correlation matrix R generated by the correlation matrix generator 32 and performs direction estimation.

Note that correlation matrix generation unit 32 Oite, after combining the correlation vector Vn _{(t j),} but by calculating the spatial spectrum, using the correlation vector Vn _{(t j)} for each pass, shown in equation (12) As described above, the spatial profile calculation may be performed for each path. Note that (Equation 12) represents a direction estimation evaluation function of the jth path for the nth subcarrier signal. However, n = 1 to Ns and j = 1 to Ln.

なお、相関行列生成部３２は、（数１１）に示される相関行列Ｒではなく、（数１３）に示す相関ベクトルｚを用いても良く、この場合、空間プロファイル演算部３２は（数４）でなく、（数１４）に示す空間プロファイルを算出して、ピークレベルを検出することで、到来方向推定値とする。ここで、Ｖ_ｎ、ｍ（ｔ_ｊ）は、相関ベクトルＶｎ（ｔ_ｊ）の第ｍ番目の要素を表す。

The correlation matrix generation unit 32 may use the correlation vector z shown in (Equation 13) instead of the correlation matrix R shown in (Equation 11). In this case, the spatial profile calculation unit 32 uses (Equation 4). Instead, the spatial profile shown in (Equation 14) is calculated and the peak level is detected to obtain the estimated arrival direction. Here, V _{n, m} (t _j ) represents the mth element of the correlation vector Vn (t _j ).

なお、本実施の形態における分割帯域方向推定部４では、ビームフォーマ法を用いて方向推定をおこなっているが、菊間著、「アレーアンテナによる適応信号処理」（科学技術出版）等で情報開示されているＭＵＳＩＣ法、ＥＳＰＲＩＴ法といった固有値分解手法や、相関行列の逆行列演算を含むＣａｐｏｎ法等の到来方向推定の高分解能手法を、（数３）あるいは（数１１）で示される相関行列生成部２２あるいは３２の出力である相関行列Ｒに対し、適用可能である。ただし、サブキャリア信号群に属するサブキャリア信号数Ｎｃがアレー素子数よりも小さい場合は、相関行列生成部２２の出力である相関行列Ｒのランク数がフルランクにならないケースが考えられるため、サブキャリア信号数Ｎｃに応じて、あるいは相関行列生成部３２を用いる場合は、サブキャリア信号数Ｎｃとパス数Ｌｎを加算した数に応じて、方向推定アルゴリズムを適宜選択する必要がある。また、アレーアンテナ１の構成が等間隔直線アレー配置である場合、相関行列生成部２２あるいは３２で得られる相関行列Ｒに対し、空間スムージング処理の適用や、ユニタリ変換行列を乗算することでの方向ベクトルを実数化したビームスペースでの到来方向推定処理も適用も可能である。

In the subband direction estimation unit 4 in this embodiment, direction estimation is performed using the beamformer method. However, information is disclosed by Kikuma, “Adaptive signal processing by array antenna” (Science and Technology Publishing). A correlation matrix generation unit represented by (Equation 3) or (Equation 11), which is a high-resolution method of direction-of-arrival estimation such as the eigenvalue decomposition method such as the MUSIC method and ESPRIT method, and the Capon method including inverse matrix calculation of the correlation matrix The present invention can be applied to the correlation matrix R having 22 or 32 outputs. However, if the number of subcarrier signals Nc belonging to the subcarrier signal group is smaller than the number of array elements, the number of ranks of the correlation matrix R that is the output of the correlation matrix generation unit 22 may not be full rank. When the correlation matrix generation unit 32 is used according to the number of carrier signals Nc or according to the number obtained by adding the number of subcarrier signals Nc and the number of paths Ln, it is necessary to appropriately select a direction estimation algorithm. Further, when the configuration of the array antenna 1 is an equally-spaced linear array arrangement, the direction obtained by applying a spatial smoothing process or multiplying the correlation matrix R obtained by the correlation matrix generation unit 22 or 32 by a unitary transformation matrix It is also possible to apply the direction of arrival estimation processing in the beam space in which the vector is realized as a real number.

  The subcarrier transmission may be an orthogonal frequency division multiplexing (OFDM) subcarrier signal. In this case, a frequency at which each subcarrier signal is orthogonal within the OFDM symbol section is selected and used. Also, it can be applied to the MC-CDMA system that is code spread multiplexed in the frequency axis direction. In this case, the pilot signal multiplexed for each individual user embedded in the subcarrier signal is used for each user. By calculating the pilot correlation value of each subcarrier signal, the same effect can be obtained by performing the operation described in the embodiment.

  In addition, the MC / DS-CDMA system in which code spread multiplexing is performed in the time axis direction can be similarly applied. In this case, the user signal code-division multiplexed in the time axis direction of each subcarrier signal is despread. By calculating the pilot correlation value of each subcarrier signal for each user after extraction, the same effect can be obtained by performing the operation described in the embodiment.

  When there is a code division multiplexed user, the division band array weight generation unit 5 has a main beam in the estimation direction of the division band direction estimation unit 4 for each subcarrier signal group in the direction of the desired user. A beam forming function for reducing interference between users that are code spread multiplexed may be added by generating array weights that form nulls in the direction of other users.

(Embodiment 2)
FIG. 5 is a block diagram showing the configuration of the adaptive antenna radio communication apparatus according to Embodiment 2 of the present invention, and the direction of each divided band direction estimation unit 4 in the configuration of FIG. 1 described in Embodiment 1. An operation for forming transmission directivity is performed for each subcarrier based on the estimation result. Note that the block diagram until the direction estimation result of the divided band direction estimation unit 4 is obtained is the same as that in the first embodiment and is omitted. The adaptive antenna radio communication apparatus in FIG. 5 includes a subcarrier transmission weight generation unit 40 that generates a transmission array weight based on the estimation result of the divided band direction estimation unit 4, and duplicates the transmission subcarrier signals by the number of transmission array elements. The subcarrier transmission directivity forming unit 41 that multiplies the signal by the transmission array weight, the mixer 42 that mixes the weighted subcarrier signal, and the radio transmission unit 43 that converts the output of the mixer 42 to a radio frequency. Is done. FIG. 5 shows a configuration example when the number of antenna elements Na = 2, the number of subcarriers Ns = 2, and the number of divided bands Nd = 2. The operation will be described below with reference to FIG.

  Based on the high-frequency signal s1 transmitted by the multi-carrier method received by the array antenna 1, until the arrival direction is estimated for each divided band by the divided band direction estimation units 4-1 to Nd, the same as in the first embodiment. There is no explanation here.

  The subcarrier transmission weight generation unit 40 generates a transmission array weight based on the estimation results of the Nd divided band direction estimation units 4. The generation of the transmission array weight is performed differently depending on the duplex method of the wireless communication system. For example, the following different operations are performed by a time division multiplexing (TDD) method and a frequency multiplexing (FDD) method.

  In the case of the TDD scheme, the transmission band and the reception band are shared in a time division manner. Therefore, based on the estimation direction results in the division band direction estimation units 4-1 to Nd for each division band, the division band array weight generation unit 5- The array weight generated by each of 1 to Nd is used as the transmission array weight Ws. As another method, when the spread (deviation) over the entire communication band of the direction estimation results in the divided band direction estimation units 4-1 to Nd for each divided band is large, there is a radio in which a plurality of users exist by code spread multiplexing. In the case of a communication system, there arises a problem that inter-user interference increases, and therefore any one of the following operations is applied.

  1) From the estimation direction results in the divided band direction estimation units 4-1 to Nd for each divided band, the estimated direction giving the maximum received power in all divided bands (the divided band direction estimating units 4-1 to 4-1 for each divided band) A transmission array weight Ws that forms a transmission directional beam in the maximum peak direction in the spatial profile calculated with Nd is generated.

  2) Deviations in all communication bands in the estimated direction are calculated from the estimation direction results in the divided band direction estimation units 4-1 to Nd for each divided band, and when the deviation is smaller than a predetermined value, the divided band direction estimation unit 4 If the average direction of the estimated direction results of −1 to Nd is larger than a predetermined value, the estimated direction higher in received power in all the divided bands (the divided band direction estimating units 4-1 to Nd for each divided band). A transmission array weight Ws for directing a plurality of main beams in the higher-order peak direction in each calculated spatial profile is generated.

  In the case of the FDD scheme, although the transmission band and the reception band are different, one of the following operations is applied based on the estimated values of the respective divided band direction estimation units 4-1 to Nd.

1) From the estimation direction results in the divided band direction estimation units 4-1 to Nd for each divided band, the estimated direction giving the maximum received power in all divided bands (the divided band direction estimating units 4-1 to 4-1 for each divided band) A transmission array weight Ws that forms a transmission directional beam in the maximum peak direction in the spatial profile calculated with Nd is generated.

  2) Deviations in all communication bands in the estimated direction are calculated from the estimation direction results in the divided band direction estimation units 4-1 to Nd for each divided band, and when the deviation is smaller than a predetermined value, the divided band direction estimation unit 4 If the average direction of the estimated direction results of −1 to Nd is larger than a predetermined value, the estimated direction higher in received power in all the divided bands (the divided band direction estimating units 4-1 to Nd for each divided band). A transmission array weight Ws for directing a plurality of main beams in the higher-order peak direction in each calculated spatial profile is generated.

Subcarrier transmission directivity forming sections 41-1 to Ns distribute transmission subcarrier signals 41-1 to Ns obtained by modulating transmission data in a predetermined modulation format to a number equal to the number of elements Na of array antenna 1, For each, the transmit array weights Ws = [w ₁ , w ₂ ,. . . , W _na ] is multiplied and output to the mixers 42-1 to Na. The mixers 42-1 to Na arrange the subcarrier signals at the frequency intervals to which the output signals corresponding to the number of array elements of the subcarrier transmission directivity forming units 41-1 to Ns weighted with directivity are respectively assigned. To mix. The radio transmitters 43-1 to Na perform frequency conversion of the outputs of the mixers 42-1 to Na to radio frequencies, respectively, and transmit from the antenna elements 44-1 to Na constituting the array antenna 44.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, multipath interference is reduced by performing directional transmission in the estimated direction in the divided band direction estimation units 4-1 to Nd, and the communication Quality is improved. In addition, in the estimated direction that gives the maximum received power in all the divided bands or the deviation of the direction estimation value for each divided band in all the communication bands, the received power is higher in the directional transmission direction in the divided bands. By limiting to the direction, there is an effect that the directional transmission can be efficiently performed in a form in which the interference between users is suppressed. Interference between users can be suppressed and system capacity can be improved.

  The subcarrier transmission used for transmission may be an orthogonal frequency division multiplexed (OFDM) subcarrier signal. In this case, a frequency at which each subcarrier signal is orthogonal in the OFDM symbol section is selected and used. Also, it can be applied to the MC-CDMA system that is code spread multiplexed in the frequency axis direction, and the same effect can be obtained by performing the operation described in the embodiment for each user. In addition, the MC / DS-CDMA system in which code spread multiplexing is performed in the time axis direction can be similarly applied. In this case, the same effect can be obtained by performing the operation described in the embodiment for each user. .

  In addition, when there is a code division multiplexed user, the subcarrier transmission weight generation unit 40 has a main beam in the estimation direction of the division band direction estimation unit 4 for each subcarrier signal group in the direction of the desired user, A beam forming function for reducing interference between users that are code spread multiplexed may be added by generating array weights that form nulls in the direction of other users.

(Embodiment 3)
FIG. 6 is a block diagram showing the configuration of the adaptive antenna radio communication apparatus according to Embodiment 3 of the present invention. In the configuration shown in FIG. 1 described in Embodiment 1, all the signals received by array antenna 1 are shown. By using the sub-carrier signal, the full-band direction estimation unit 50 that performs direction estimation in all communication bands and the spatial profile calculated by the divided-band direction estimation unit 4 or the full-band direction estimation unit 50 is used to widen the angle. It is the structure which added the direction estimation result selection part 51 which detects and selects and outputs either direction estimation result. Note that the block diagram until the direction estimation result of the divided band direction estimation unit 4 is obtained is the same as that in the first embodiment and is omitted. Hereinafter, the differences from the first embodiment will be mainly described with reference to FIG. FIG. 6 shows a configuration example when the number of antenna elements Na = 2, the number of subcarriers Ns = 2, and the number of divided bands Nd = 2.

  Based on the high-frequency signal s1 transmitted by the multi-carrier method received by the array antenna 1, until the arrival direction is estimated for each divided band by the divided band direction estimation units 4-1 to Nd, the same as in the first embodiment. There is no explanation here.

  When the correlation matrix R represented by (Equation 3) calculated in the n-th subband 3-n is expressed as Rn (where n = 1,..., Nd). Then, Rn calculated in all the divided bands 3-1 to Nd is used as an input, and a combined sum Ra of Rn expressed by (Equation 15) is calculated. Then, for example, the spatial profile is calculated by varying the θ by a predetermined angle step Δθ, and the predetermined number M (M ≧ 1) in descending order of the peak level of the spatial profile. ) Is detected, and the average direction of arrival of subcarrier signals in all communication bands is estimated. However, a (θ) is a direction vector determined by the element arrangement of the array antenna 1, and can be expressed as (Equation 5), for example, in the case of a uniform linear array with an element interval d. Here, λ is the wavelength of the carrier wave, and θ is the 0 ° direction of the normal direction of the array. H represents complex conjugate transposition.

方向推定結果選択部５１は、全ての分割帯域方向推定部４−１〜Ｎｄの方向推定値Φ_ｋｍと、それぞれの分割帯域３―ｍでの空間プロファイル値（または到来方向推定評価関数値）Ｆ_ｍ（Φ_ｋｍ）を用いて、（数１７）に示される計算式を用いて角度広がりＡＳを算出する。ここで、ｍ＝１、．．．、Ｎｄである。また、φ_０は（数１８）で与えられ、Φｋｍは、第ｍ番目の分割帯域３−ｍでの分割帯域方向推定部４−ｍで検出された全Ｌｍ個のパスのうち、第ｋ番目のパスの到来方向を示す。算出された角度広がりＡＳを用いて、角度広がりＡＳが所定値Ｋ以下の場合、全帯域方向推定部５０の推定値を選択し、すべての分割帯域アレー重み生成部５−１〜Ｎｄに共通に出力する。一方、角度広がりＡＳが所定値Ｋより大きい場合、実施例１の形態と同様に、第ｍ番目の分割帯域３−ｍでの分割帯域方向推定部４−ｍの推定値は、分割帯域重み生成部５−ｍに出力する。ここで、ｍ＝１、．．．、Ｎｄである。また、角度広がりＡＳの別な算出方法としては、空間プロファイル値（または到来方向推定評価関数値）Ｆ_ｍ（Φ_ｋｍ）の上位を与える方向推定値Φｋｍのみを用いて、（数１７）から角度広がりＡＳを求めても良い。

The direction estimation result selection unit 51 includes direction estimation values Φ _{km of} all the divided band direction estimation units 4-1 to Nd, and spatial profile values (or arrival direction estimation evaluation function values) F in the respective divided bands 3-m. _{Using m} (Φ _km ), the angular spread AS is calculated using the calculation formula shown in (Equation 17). Where m = 1,. . . , Nd. Φ ₀ is given by (Equation 18), and Φkm is the kth of the total Lm paths detected by the divided band direction estimation unit 4-m in the mth divided band 3-m. Indicates the direction of arrival of the path. If the angular spread AS is equal to or less than the predetermined value K using the calculated angular spread AS, the estimated value of the all-band direction estimating unit 50 is selected, and is shared by all the divided band array weight generating units 5-1 to Nd. Output. On the other hand, when the angular spread AS is larger than the predetermined value K, the estimated value of the divided band direction estimation unit 4-m in the m-th divided band 3-m is the divided band weight generation as in the first embodiment. Output to section 5-m. Where m = 1,. . . , Nd. As another method for calculating the angular spread AS, only the direction estimation value Φkm that gives the higher rank of the spatial profile value (or arrival direction estimation evaluation function value) F _m (Φ _km ) is used. The spread AS may be obtained.

分割帯域アレー重み生成部５は、方向推定結果選択部５１での方向推定選択結果に従い、主ビーム方向を特定方向に向けるアレー重みを生成し、サブキャリア指向性形成部６により、生成されたアレー重みを各サブキャリア信号に対し共通に乗算合成した信号を出力する。すなわち、第ｍ番目の分割帯域３−ｍにおける分割帯域アレー重み生成部５−ｍは、第ｍ番目の分割帯域３−ｍに属するサブキャリア信号群に対し、方向推定結果選択部５１での方向推定選択結果に従い、主ビーム方向を特定方向に向けるアレー重みを生成し、サブキャリア指向性形成部６−ｍは、生成されたアレー重みを各サブキャリア信号に対し共通に乗算合成した信号を出力する動作をすべてのｍ＝１、．．．、Ｎｄに対して行う。

The subband array weight generation unit 5 generates an array weight for directing the main beam direction in a specific direction according to the direction estimation selection result in the direction estimation result selection unit 51, and the subcarrier directivity forming unit 6 generates the array weight. A signal obtained by multiplying and combining the weights of the subcarrier signals in common is output. That is, the subband array weight generation unit 5-m in the mth subband 3-m performs the direction in the direction estimation result selection unit 51 for the subcarrier signal group belonging to the mth subband 3-m. According to the estimation selection result, an array weight for directing the main beam direction to a specific direction is generated, and the subcarrier directivity forming unit 6-m outputs a signal obtained by multiplying and combining the generated array weight by each subcarrier signal. For all m = 1,. . . , Nd.

  The demodulator 7 performs a demodulation operation using each subcarrier signal received with directivity and receives data.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, the direction estimation result selection unit 51 detects the angular spread of the subcarrier signal in the entire communication band, thereby Different directivity formation every time or directivity formation common to all the divided bands 3 can be switched according to the angular spread AS. As a result, when the angular spread AS is small, by estimating the average direction of arrival for all subcarrier signals, even if the reception level of some bands is low due to frequency selective fading, the entire communication band is robust. It is possible to estimate the direction of arrival.

  The angle spread detection in the direction estimation result selection unit 51 is calculated based on the spread of the arrival direction estimation value for each divided band. However, a detection method based on the spatial profile calculated by the all-band direction estimation unit 50 is also available. Applicable. As a method for calculating the angular spread from the spatial profile, for example, N.I. S. M.M. Information is disclosed in Shah et al., “Simultaneous Estimation of Direction of Arrival and Angular Spread Using MUSIC Algorithm”, 2000 IEICE Communication Society B-1-31. Similarly, using the angular spread AS calculated from the spatial profile from the correlation matrix Ra calculated in (Equation 15), the estimation results of the entire band direction estimation unit 50 or the divided band direction estimation units 4-1 to Nd are selectively selected. Can be switched.

  In the present embodiment, the all-band direction estimation unit 50 that performs direction estimation using subcarrier signals in all communication bands is used. However, the all-band direction estimation unit 50 uses the subband direction estimation unit 4 as a subband direction estimation unit 4. A configuration may be used in which direction estimation is performed with a division number larger than the carrier signal division number Ns.

  Note that the all-divided band direction estimation unit 50 in this embodiment performs direction estimation using the beamformer method, but information is disclosed by Kikuma, "Adaptive signal processing using an array antenna" (Science and Technology Publishing). A high-resolution method of arrival direction estimation, such as the eigenvalue decomposition method such as the MUSIC method and ESPRIT method, and the Capon method including inverse matrix calculation of the correlation matrix, is applied using the correlation matrix Ra shown in (Equation 15). It is possible. However, when the number of subcarrier signals Nc belonging to the divided band 3 or the number of paths is smaller than the number of array elements, there is a case where the rank number of the correlation matrix that is the output of the correlation matrix generation unit 22 does not become full rank. Depending on the number of ranks or the number of passes, adaptive combination with the beamformer method can be considered. Further, when the configuration of the array antenna 1 is an equidistant linear array arrangement, the direction vector obtained by multiplying the correlation matrix Ra shown in (Equation 15) by a spatial smoothing process or a unitary transformation matrix is realized as a real number. The direction-of-arrival estimation process in the beam space can be similarly applied.

  The subcarrier transmission may be an orthogonal frequency division multiplexing (OFDM) subcarrier signal. In this case, a frequency at which each subcarrier signal is orthogonal within the OFDM symbol section is selected and used. Also, it can be applied to the MC-CDMA system that is code spread multiplexed in the frequency axis direction. In this case, the pilot signal multiplexed for each individual user embedded in the subcarrier signal is used for each user. By calculating the pilot correlation value of each subcarrier signal, the same effect can be obtained by performing the operation described in the embodiment.

  In addition, the MC / DS-CDMA system in which code spread multiplexing is performed in the time axis direction can be similarly applied. In this case, the user signal code-division multiplexed in the time axis direction of each subcarrier signal is despread. By calculating the pilot correlation value of each subcarrier signal for each user after extraction, the same effect can be obtained by performing the operation described in the embodiment.

  Also, when there is a code division multiplexed user, the division band array weight generation unit 5 has a main beam in the estimated direction selected by the direction estimation result selection unit 51 for each subcarrier signal group in the direction of the desired user. A beam forming function for reducing interference between users that are code spread multiplexed may be added by generating array weights that form nulls in the direction of other users being multiplexed.

(Embodiment 4)
FIG. 7 is a block diagram showing the configuration of the adaptive antenna radio communication apparatus according to Embodiment 4 of the present invention. In the configuration shown in FIG. 5 described in Embodiment 2, all the signals received by array antenna 1 are shown. Angular spread detection by using a full band direction estimation unit 50 that performs direction estimation in all bands by using a subcarrier signal and a spatial profile calculated by the divided band direction estimation unit 4 or the full band direction estimation unit 50 In addition, a direction estimation result selection unit 51 that selects and outputs one of the direction estimation results is added. Note that the block diagram until the direction estimation result of the divided band direction estimation unit 4 is obtained is the same as that in the first embodiment and is omitted. Hereinafter, the differences from the first embodiment will be mainly described with reference to FIG. FIG. 7 shows a configuration example when the number of antenna elements Na = 2, the number of subcarriers Ns = 2, and the number of divided bands Nd = 2.

  Based on the high-frequency signal s1 transmitted by the multi-carrier method received by the array antenna 1, until the arrival direction is estimated for each divided band by the divided band direction estimation units 4-1 to Nd, the same as in the first embodiment. There is no explanation here.

  Similar to the operation described in the third embodiment, the all-band direction estimating unit 50 represents the correlation matrix R represented by (Equation 3) calculated in the n-th divided band 3-n as Rn ( However, n = 1,..., Nd) and Rn calculated in all the divided bands 3-1 to Nd are input, and a combined sum Ra of Rn expressed by (Equation 15) is calculated. Then, for example, the spatial profile is calculated by varying the θ by a predetermined angle step Δθ, and the predetermined number M (M ≧ 1) in descending order of the peak level of the spatial profile. ) Is detected, and the average direction of arrival of subcarrier signals in all communication bands is estimated. However, a (θ) is a direction vector determined by the element arrangement of the array antenna 1, and can be expressed as (Equation 5), for example, in the case of a uniform linear array with an element interval d. Here, λ is the wavelength of the carrier wave, and θ is the 0 ° direction of the normal direction of the array. H represents complex conjugate transposition.

The direction estimation result selection unit 51 includes direction estimation values Φ _{km of} all the divided band direction estimation units 4-1 to Nd, and spatial profile values (or arrival direction estimation evaluation function values) F in the respective divided bands 3-m. _{Using m} (Φ _km ), the angular spread AS is calculated using the calculation formula shown in (Equation 17). Where m = 1,. . . , Nd. Φ ₀ is given by (Equation 18), and Φkm is the kth of the total Lm paths detected by the divided band direction estimation unit 4-m in the mth divided band 3-m. Indicates the direction of arrival of the path. Using the calculated angular spread AS, when the angular spread AS is a predetermined value K or less, the estimated value of the all-band direction estimating unit 50 is selected and output to the subcarrier transmission weight generating unit 40. On the other hand, when the angular spread AS is larger than the predetermined value K, the estimated values of the divided band direction estimators 4-1 to Nd in the divided bands 3-1 to Nd are transmitted as subcarrier transmissions as in the second embodiment. The data is output to the weight generation unit 40. Where m = 1,. . . , Nd. As another method for calculating the angular spread AS, only the direction estimation value Φkm that gives the higher rank of the spatial profile value (or arrival direction estimation evaluation function value) F _m (Φ _km ) is used. The spread AS may be obtained.

  The subcarrier transmission weight generation unit 40 generates a transmission array weight based on the output of the direction estimation result selection unit 51. When the angular spread AS is larger than the predetermined value K, since the estimated values of the divided band direction estimation units 4-1 to Nd in the divided bands 3-1 to Nd are input, the subcarrier transmission weight in the form of the second embodiment Since the same operation as that of the generation unit 40 is performed, the description thereof is omitted here. When the angular spread AS is equal to or smaller than the predetermined value K, the estimated value of the all-band direction estimating unit 50 is selected and inputted, so that a transmission array weight for directing the main beam in the direction of the estimated direction value is generated.

Subcarrier transmission directivity forming sections 41-1 to Ns distribute transmission subcarrier signals 41-1 to Ns obtained by modulating transmission data in a predetermined modulation format to a number equal to the number of elements Na of array antenna 1, For each, the transmit array weights Ws = [w ₁ , w ₂ ,. . . , W _na ] is multiplied and output to the mixers 42-1 to Na. The mixers 42-1 to Na arrange the subcarrier signals at the frequency intervals to which the output signals corresponding to the number of array elements of the subcarrier transmission directivity forming units 41-1 to Ns weighted with directivity are respectively assigned. To mix. The radio transmitters 43-1 to Na perform frequency conversion of the outputs of the mixers 42-1 to Na to radio frequencies, respectively, and transmit from the antenna elements 44-1 to Na constituting the array antenna 44.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment and the second embodiment, the directivity formation different for all the divided bands or the transmission directivity formation common to all the divided bands 3 is obtained. It can be switched according to the angular spread AS. As a result, when the angular spread AS is small, by estimating the average direction of arrival for all subcarrier signals, even if the reception level of some bands is low due to frequency selective fading, the entire communication band is robust. Directional transmission using the result is effective, and an effect that more stable operation is ensured is obtained. Interference between users can be suppressed and system capacity can be improved.

  In the present embodiment, the all-band direction estimation unit 50 that performs direction estimation using subcarrier signals in all communication bands is used. However, the all-band direction estimation unit 50 uses the subband direction estimation unit 4 as a subband direction estimation unit 4. A configuration may be used in which direction estimation is performed with a division number larger than the carrier signal division number Ns.

  The subcarrier transmission may be an orthogonal frequency division multiplexed (OFDM) subcarrier signal. In this case, the subcarrier transmission is used by selecting a frequency at which each subcarrier is orthogonal within the OFDM symbol section. Further, the present invention can also be applied to an MC-CDMA system that is code-multiplexed and spread in the frequency axis direction. In this case, for each user that is code-division multiplexed, an embodiment is described after extracting a user signal after despreading the spreading code. Perform the operation described in.

  In addition, the MC-DS-CDMA system that is code-multiplexed in the time axis direction can be similarly applied. In this case, for each user that has been code-division-multiplexed, the user signal is extracted after despreading the spreading code. The operation described in the embodiment is performed.

  When there is a user that is code-division multiplexed, the subcarrier transmission weight generation unit 40 has a main beam in the direction of estimation selected by the direction estimation result selection unit 51 for each subcarrier signal group in the direction of the desired user. A beam forming function for reducing interference between users that are code spread multiplexed may be added by generating array weights that form nulls in the direction of other users being multiplexed.

  An adaptive antenna wireless communication apparatus according to the present invention includes an array antenna including a plurality of antenna elements that receive a high-frequency signal transmitted by multicarrier, and a high-frequency signal received for each antenna element is divided into a plurality of subcarrier signals. Dividing the wave demultiplexer and the entire communication band for multicarrier transmission into Nd (where Nd is 2 or more and a natural number less than the number of subcarriers used for multicarrier transmission). Nd subband direction estimation units that perform radio wave arrival direction estimation using the subcarrier signal group to which the subcarrier signals belong, and an array weight having a directional beam in the estimation direction of the subband direction estimation unit for each of the subbands A subband array weight generation unit and each subcarrier belonging to the subband corresponding to the array weight generated for each subband A subcarrier directivity forming unit that forms a directivity by multiplying and combining signals and a demodulating unit that demodulates data using the output of the subcarrier directivity forming unit. The direction of arrival of the subcarrier signal group can be estimated and directivity reception based on the direction estimation result can be performed.

  In the adaptive antenna radio communication device, the divided band direction estimation unit calculates a pilot signal correlation value with each input subcarrier signal using a known pilot signal embedded in the subcarrier signal, and is different. The direction of arrival is estimated based on the correlation value of the pilot signal correlation value calculated between the subcarrier signals received by the antenna element, and the direction estimation based on the phase of the pilot correlation value can be performed. Have

Also, the adaptive antenna radio communication apparatus, divided band direction estimating unit, the number of subcarriers belonging to the sub-carrier signal group in the L, the m-th element of the column vector V _k, the k-th subcarrier signal The correlation that can be expressed as R = V ₁ V ₁ ^H + V ₂ V ₂ ^H +... + V _L V _L ^H where H is a complex conjugate transpose operator. The arrival direction estimation is performed using the matrix R, and it has the effect that the direction obtained by averaging the arrival directions of the subcarrier signal group can be detected with high accuracy.

In the adaptive antenna radio communication apparatus, the division band direction estimation unit has L subcarriers belonging to the subcarrier signal group, and a pilot signal at the mth antenna element in the kth subcarrier signal. A column vector having a correlation value as the m-th element is V _k , V _kx is an x-th element of the column vector V _k (where x is a natural number equal to or less than the number of antenna elements), and * is a complex conjugate transpose operator. The arrival direction is estimated using a correlation vector z expressed as z = V _1x ^* V ₁ + V _2x ^* V ₂ +... + V _Lx ^* V _N , and the arrival direction of the subcarrier signal group It is possible to detect the averaged direction with high accuracy.

  In the adaptive antenna radio communication device, the division band direction estimation unit performs a cross-correlation operation with each input subcarrier signal using a known pilot signal embedded in the subcarrier signal, thereby delay profile. A plurality of path arrival timings are detected from the delay profile, and for each arrival path timing, based on the correlation value of the pilot signal correlation value calculated between subcarrier signals received by different antenna elements. It is characterized in that arrival direction estimation is performed, and has an effect that the arrival direction of a multipath wave included in each subcarrier signal can be estimated.

として表せる相関行列Ｒを用いて到来方向推定を行うことを特徴とし、サブキャリア信号毎に含まれるマルチパス波の到来方向を推定を精度よく行えるという作用を有する。 In the adaptive antenna radio communication apparatus, the division band direction estimation unit has L subcarriers belonging to the subcarrier signal group, and the pth arrival path (all arrival paths) in the kth subcarrier signal. When the column vector having the pilot signal correlation value at the m-th antenna element of S) as the m-th element is V _k (p) and H is the complex conjugate transpose operator,

The arrival direction estimation is performed using the correlation matrix R expressed as follows, and the arrival direction of the multipath wave included in each subcarrier signal can be estimated with high accuracy.

として表せる相関ベクトルｚを用いて到来方向推定を行うことを特徴とし、サブキャリア信号毎に含まれるマルチパス波の到来方向を推定を精度よく行えるという作用を有する。 In the adaptive antenna radio communication apparatus, the division band direction estimation unit has L subcarriers belonging to the subcarrier signal group, and the pth arrival path (all arrival paths) in the kth subcarrier signal. A column vector having a pilot signal correlation value at the m-th antenna element of S) as the m-th element is V _k (p), and V _kx (p) is the x-th column vector V _k (p). Element (where x is a natural number less than or equal to the number of antenna elements) and * is a complex conjugate transpose operator,

The direction of arrival is estimated using a correlation vector z expressed as follows, and the direction of arrival of a multipath wave included in each subcarrier signal can be estimated with high accuracy.

  In the adaptive antenna radio communication device, the divided band direction estimation unit performs the direction of arrival estimation using any one of the MUSIC method, ESPRIT method, CAPON method, and Fourier method using the correlation matrix R. And has an effect that various arrival direction estimation methods can be applied.

  In the adaptive antenna radio communication apparatus, the divided band direction estimation unit applies the spatial smoothing process to the correlation matrix R, and then uses the MUSIC method, ESPRIT method, CAPON method, or Fourier method to determine the direction of arrival. The estimation is characterized in that the estimation accuracy can be ensured even when a correlation wave exists.

  In the adaptive antenna radio communication apparatus, the divided band direction estimation unit applies the unitary transformation process to the correlation matrix R, and then uses the MUSIC method, ESPRIT method, CAPON method, or Fourier method to determine the direction of arrival. In the case where the array antenna is an equally spaced linear array, the direction vector can be converted to a real number, so that the amount of calculation processing can be reduced.

  Further, the adaptive antenna radio communication apparatus has a predetermined deviation of the direction estimation result between the all-band direction estimating unit that performs direction-of-arrival estimation using subcarrier signals in all communication bands and the Nd divided band direction estimating units. A direction estimation result selection unit that outputs an estimation value of the divided band direction estimation unit when the deviation is larger than a predetermined value, A subband array generation unit that generates an array weight using the output of the estimation result selection unit, and can switch the directivity control method adaptively from dispersion in the direction of arrival within the band. Has an effect.

  The adaptive antenna wireless communication device detects an angular spread from an all-band direction estimation unit that performs direction-of-arrival estimation using subcarrier signals in all communication bands and a spatial profile calculated by the all-band direction estimation unit. When the angular spread is equal to or less than a predetermined value, the estimated value of the all-band direction estimating unit is selected and output. When the angular spread is larger than the predetermined value, the estimated value of the divided band direction estimating unit is output. And a division band array generation unit that generates an array weight using an output of the direction estimation result selection unit, and adaptively controls directivity from the spread of the arrival direction in the band. This has the effect that the method can be switched.

  The adaptive antenna wireless communication apparatus is based on the estimated direction result selected by the direction estimation result selection unit in a wireless system that performs multicarrier transmission using a time division duplex (TDD) method or a frequency division duplex (FDD) method. A subcarrier transmission weight generation unit that calculates a transmission array weight for forming one transmission directional beam for each divided band, and a directional beam transmission by multiplying the transmission subcarrier signal by the transmission array weight for each of the divided bands And a sub-carrier transmission directivity forming unit, which has an effect that the directivity control method can be switched adaptively from the spread of the arrival direction in the band.

  The adaptive antenna radio communication apparatus uses an array weight generated by a subband array weight generation unit for each subband as a subarray weight in a radio system that performs multicarrier transmission using a time division duplex (TDD) method. A carrier transmission weight generation unit, and a subcarrier transmission directivity formation unit that transmits a directional beam using a transmission array weight common to each of the divided bands. It has the effect that transmission can be performed using the same directivity.

  The adaptive antenna radio communication device is based on an estimation direction result in a subband direction estimation unit for each subband in a radio system that performs multicarrier transmission using a time division duplex (TDD) scheme or a frequency division duplex (FDD) scheme. A subcarrier transmission weight generator for calculating a transmission array weight for forming a transmission directional beam in an estimated direction giving the maximum received power among the divided bands, and a directional beam common to all the divided bands using the transmission array weight And a sub-carrier transmission directivity forming unit for transmitting a transmission beam, and has an effect that a transmission beam can be formed in a path direction that gives the maximum reception power in the divided band.

  The adaptive antenna radio communication device is based on an estimation direction result in a subband direction estimation unit for each subband in a radio system that performs multicarrier transmission using a time division duplex (TDD) scheme or a frequency division duplex (FDD) scheme. A deviation of the estimated direction is calculated, and when the deviation is equal to or smaller than a predetermined value, the average direction of all the direction estimation values obtained by the divided band direction estimation unit is calculated. It is equipped with a subcarrier transmission weight generation unit that calculates transmission array weights that form transmission directional beams that become multi-beams in the estimated direction that gives higher received power, and is adaptive from the spread of the arrival direction in the band The directivity control method can be switched.

  The adaptive antenna radio communication apparatus is characterized in that the subcarrier transmission is an orthogonal frequency division multiplexing (OFDM) subcarrier signal, and has the effect of being able to transmit with a modulation scheme with high frequency use efficiency.

  The adaptive antenna radio communication apparatus is characterized in that the subcarrier transmission is a subcarrier signal that is user-multiplexed by code-spreading multiplexing in the frequency axis direction, and is applied to a system that can perform user multiplexing by code-spreading multiplexing. It has an action that can be done.

  The adaptive antenna radio communication apparatus is characterized in that the subcarrier transmission is a subcarrier signal that is user-multiplexed by code-spread multiplexing in the time axis direction, and is applied to a system capable of user multiplexing by code-spread multiplexing. It has an action that can be done.

  Also, the adaptive antenna radio communication apparatus generates a transmission array weight or a reception array weight for each multiplexed user in the case of subcarrier transmission using a subcarrier signal multiplexed by code spreading multiplexing, and directivity reception is performed. And has the effect of enabling optimal directivity control for each divided band for each of multiple users.

  In the adaptive antenna radio communication device, the division band array weight generation unit has a directional beam in the direction estimation result of the division band direction estimation unit in the corresponding division band, and is estimated by other users being multiplexed. Is characterized by generating an array weight for forming a null, and has an effect of enabling optimum directional reception in which a null is formed in the interference direction for each divided band for each of multiple users.

  In the adaptive antenna radio communication apparatus, the subcarrier transmission weight generation unit generates a transmission division band array weight having a directional beam in the desired user direction and forming a null in the multiplexed other user direction. It has the feature that it has the effect of enabling optimum directional transmission / reception in which a null is formed in the interference direction for each divided band for each of multiple users.

1 Array Antenna 1-1 to Na Antenna Element 2-1 to Na Demultiplexer 3-1 to Nd Divided Bands 4-1 to Nd Divided Band Direction Estimation Units 5-1 to Nd Divided Band Array Weight Generation Units 6-1 to 6-1 Nd subcarrier directivity forming unit 7 demodulating unit

Claims (4)

An array antenna for receiving a multi-carrier transmitted signal;
One reception array weight for forming a reception directional beam using a plurality of subcarrier signals included in a subcarrier signal group belonging to the division band for each division band obtained by dividing a communication band used for multicarrier transmission A reception weight generation unit for generating
Subcarrier reception for generating a weighted subcarrier signal by multiplying the received array weight generated for each division band by a subcarrier signal belonging to the division band among the received signals A directivity forming part;
And a decoding unit configured to decode the weighted subcarrier signal. An array antenna for receiving a signal transmitted by multicarrier, and a plurality of subcarrier signals included in a subcarrier signal group belonging to the divided band for each divided band obtained by dividing the communication band used for the multicarrier transmission, A reception weight generator for generating a reception array weight for forming a plurality of reception directional beams;
A subcarrier signal that generates a plurality of weighted subcarrier signals by multiplying the received array weight generated for each divided band by a subcarrier signal belonging to the divided band among the received signals. A carrier reception directivity forming unit;
And a decoding unit that decodes the plurality of weighted subcarrier signals. Receive multi-carrier transmitted signal,
One reception array for forming a reception directional beam using a plurality of subcarrier signals included in the subcarrier signal group belonging to the division band for each division band obtained by dividing the communication band used for the multicarrier transmission. Generate weights,
A weighted subcarrier signal is generated by multiplying the received array weight generated for each divided band by a subcarrier signal belonging to the divided band among the received signals,
Decoding the weighted subcarrier signal;
Wireless communication method. Receive multi-carrier transmitted signal,
A receiving array for forming a plurality of receiving directional beams using a plurality of subcarrier signals included in a subcarrier signal group belonging to the divided band for each divided band obtained by dividing the communication band used for the multicarrier transmission. Generate weights,
Multiplying the reception array weight generated for each division band by a subcarrier signal belonging to the division band among the received signals to form a transmission signal with a plurality of weights;
A wireless communication method for decoding the plurality of weighted subcarrier signals.

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