JP4260653B2 - Transmitter for spatial multiplexing transmission - Google Patents

Description

  The present invention relates to propagation environment estimation and fading compensation directivity control when performing spatial multiplexing transmission using an antenna for a radio communication system, and more particularly to a spatial multiplexing transmission apparatus.

The spatial multiplexing transmission apparatus is a transmission apparatus that realizes high-speed transmission without increasing the frequency band by transmitting different signals from a plurality of antenna elements.
FIG. 8 shows a conventional spatial multiplexing transmission apparatus (see, for example, Non-Patent Document 1).
As shown in the figure, the conventional spatial multiplexing transmission apparatus includes a plurality of transmission antenna elements 8011 to 801N, transmission apparatuses 8021 to 802N, and a serial-parallel converter 803.

A transmission signal generates a plurality of signal sequences T1 to TN by a serial-parallel converter 803, and is transmitted from transmission antenna elements 8011 to 801N at the same time and at the same frequency by different transmission devices 8021 to 802N.
At the receiving station, for example, decoding is performed using the same number of antennas as that of the transmitting station. An example of the decoding method is shown below. When the signal received at the receiving station antenna element is R _{1 to} R _N , the transfer function transmitted from the antenna i and received by the antenna j is h _ij, and the noise in each received signal is n _{1 to} n _N , When signals are transmitted by a spatial multiplexing transmission apparatus, the received signals R _{1 to} R _N can be expressed as follows.

したがって、受信装置では以下の演算を行うことによって、送信信号を復号することが可能となる。

Therefore, the reception apparatus can decode the transmission signal by performing the following calculation.

と表すことができる．ここでＴ_１’〜Ｔ_Ｎ’は受信装置で推定した送信信号である。このようにすることによって、周波数帯域を増大せずにアンテナ数倍の伝送速度を実現することが可能となる。
ただし、この方法を用いた場合には各アンテナから異なった信号を送信するため、送信局におけるアンテナ指向性利得、送信ダイバーシチ利得が得られず、ＳＮ比の低下、他局への干渉の増大が生じるという問題があった。

It can be expressed as. Here, T ₁ ′ to T _N ′ are transmission signals estimated by the receiving apparatus. By doing so, it is possible to realize a transmission speed several times the number of antennas without increasing the frequency band.
However, when this method is used, since different signals are transmitted from the respective antennas, the antenna directivity gain and the transmission diversity gain at the transmitting station cannot be obtained, and the SN ratio is decreased and the interference with other stations is increased. There was a problem that occurred.

  Next, a conventional spatial multiplexing transmission apparatus that improves transmission quality by forming a multi-beam will be described. FIG. 9 shows the configuration of a conventional spatial multiplexing transmission apparatus using multi-beam forming (see, for example, Non-Patent Document 2). In this figure, this spatial multiplexing transmission device is composed of transmitting antenna elements 9011 to 901N, a multi-beam forming device 902, transmitting devices 9031 to 903K, and a serial-parallel converter 904.

In the above configuration, the transmission signal generates a plurality of signal sequences T _{1 to} T _K by the serial-parallel converter 904, the transmission devices 9031 to 903 K form K-sequence transmission signal sequences, and the multi-beam forming device 902 respectively Output signals to the respective antenna elements for forming different directivities are formed and transmitted from the transmitting antenna elements 9011 to 901N at the same time and at the same frequency. Here, the multi-beam forming apparatus forms a multi-beam as follows.

First, a singular value decomposition (H = UDV ^H ) of the transfer function matrix H is performed to obtain a unitary matrix V and a diagonal matrix having singular values as elements. Here, the superscript H represents a conjugate transpose, and the transfer function matrix is represented by the following equation.

次に、特異値の大きい方からＫ個を選択し、各特異値に対応したユニタリ行列Ｖの列ベクトルｖ_１〜ｖ_Ｋを選択し、各列ベクトルを用いて以下の式によって各アンテナ素子から送信する送信信号Ｓ_１〜Ｓ_Ｎを形成する。

Next, K is selected from the larger singular values, the column vectors v _{1 to} v _K of the unitary matrix V corresponding to the singular values are selected, and each column element is used to calculate each of the antenna elements by the following formula. The transmission signals S _{1 to} S _N to be transmitted are formed.

この方法では指向性利得が得られ、さらにＮ個のアンテナ素子からＫビームを形成する（Ｎ≧Ｋ）とすることによって良好なビームを選択できるため、ダイバーシチ効果も得ることができる。
ただし、この方法は推定した伝達関数行列のみによって形成されるため、伝達関数推定に誤差が生じると伝送品質の大きな劣化を招くという問題があり、伝達関数推定誤差の大きい環境には適用できないという問題があった。
S. Kurosaki, et al, “A SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel Canceller for MIMO Based Broadband Wireless LANs”,IEICE Trans. Commun.,2003 Miyashita,K.;Nishimura, T.; Ohgane, T.; Ogawa,Y,; Takatori,Y.: Keizo Cho;”High data-rate transmission with eigenbeam-space division multiplexing (E-SDM) in a MIMO channel,” Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th , Volume:3，24-28 Sept. 2002 Pages:1302 - 1306 vol.3

In this method, a directivity gain can be obtained, and a diversity effect can also be obtained because a good beam can be selected by forming a K beam from N antenna elements (N ≧ K).
However, since this method is formed only by the estimated transfer function matrix, if there is an error in the transfer function estimation, there is a problem that the transmission quality is greatly degraded, and it cannot be applied to an environment where the transfer function estimation error is large. was there.
S. Kurosaki, et al, “A SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel Canceller for MIMO Based Broadband Wireless LANs”, IEICE Trans. Commun., 2003 Miyashita, K.; Nishimura, T .; Ohgane, T .; Ogawa, Y ,; Takatori, Y .: Keizo Cho; ”High data-rate transmission with eigenbeam-space division multiplexing (E-SDM) in a MIMO channel, ”Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th, Volume: 3, 24-28 Sept. 2002 Pages: 1302-1306 vol.3

As described above, when directivity synthesis using an array antenna is not performed on the transmitting side when performing SDM transmission, the directivity gain of the transmitting station cannot be obtained sufficiently, resulting in degradation of transmission quality and interference with other cells. The problem of increase arises.
On the other hand, in the SDM transmission in which directivity synthesis is performed at the transmitting station, if the propagation environment estimation has an error, the beam direction is greatly deviated, so that the transmission quality deteriorates.
Therefore, even in a wireless communication system in which a propagation environment estimation error occurs, it is desired to realize a directivity forming method that improves transmission quality when spatial multiplexing transmission is performed.

  The present invention has been made in view of such circumstances, and provides a transmitter for spatial multiplexing transmission capable of obtaining a diversity effect even in an environment with an estimation error of a propagation environment and greatly improving transmission quality. The purpose is to do.

  The above-described object is achieved. The invention according to claim 1 is a spatial multiplexing transmission apparatus having a plurality of transmitting antenna elements of at least three elements, wherein the plurality of antenna elements are connected to the antenna elements. Grouping means for performing grouping into a plurality of groups, and a plurality of transmission diversity signal generating devices provided corresponding to the groups for generating signals for performing transmission diversity among the grouped groups. A serial-parallel converter that serial-parallel converts an input signal to be transmitted and generates an input signal to each of the plurality of transmission diversity signal generation devices provided for each group. To do.

The invention according to claim 2 includes at least three or more transmitting antenna elements and grouping means connected to each transmitting antenna element for grouping the transmitting antenna elements into a plurality of groups, A plurality of transmission diversity signal generation devices provided corresponding to each group for generating a signal for performing transmission diversity among the grouped groups, and serial-parallel conversion of input signals to be transmitted, A serial-parallel converter that generates an input signal to the plurality of transmission diversity signal generators provided for each group, a propagation environment estimation unit that performs propagation environment estimation at the time of reception,
Grouping determination means for determining grouping so that the transmission quality in each group is substantially constant from the propagation environment estimation result by the propagation environment estimation means, and in the grouping means, A spatial multiplexing transmission apparatus characterized in that grouping is performed based on determination by the grouping determination means.

    According to a third aspect of the present invention, in the spatial multiplexing transmission apparatus according to any one of the first and second aspects, the output signal of the grouping means is used as an input signal, and the signal is transmitted to the transmitting antenna element. A multi-directional pattern forming apparatus for generating an input signal is provided, wherein the multi-directional pattern forming apparatus forms different directivities for each input signal.

  According to a fourth aspect of the present invention, in the spatial multiplexing transmission apparatus according to any one of the first to third aspects, the average error rate of signals transmitted from each group of the transmission antennas is minimized. Transmission power allocating means for allocating transmission power to each group of the transmission antennas is provided.

  According to a fifth aspect of the present invention, in the spatial multiplexing transmission apparatus according to any one of the third and fourth aspects, each beam is obtained from singular value decomposition of a transfer function matrix in the multi-pattern directivity forming apparatus. In the grouping determination means, a beam whose singular value corresponding to the eigenbeam is equal to or greater than a preset threshold is used as a transmission beam, and in each grouping, the sum of singular values in each group is almost equal. Thus, the group is determined.

  As described above, according to the present invention, the input signal to be transmitted is divided into a plurality of groups, transmission diversity is performed, and transmission is performed from the plurality of grouped transmitting antenna elements. Diversity effect in a certain environment can be obtained, and transmission quality can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1 to FIG. 5 showing the spatial multiplexing transmission apparatus according to the first to fifth embodiments, the same reference numerals are assigned to the functional blocks having the same functions, and duplicate descriptions are omitted.

[First embodiment]
FIG. 1 shows the configuration of a spatial multiplexing transmission apparatus according to the first embodiment of the present invention. The spatial multiplexing transmission apparatus according to the first embodiment enables spatial multiplexing transmission even in a propagation environment with a large propagation environment estimation error. 1, the spatial multiplexing transmission apparatus according to the first embodiment includes a plurality of transmission antenna elements 1011 to 101M having three or more elements, a grouping unit 102, and a plurality of transmission diversity signal generation apparatuses 1031 to 103K. And a serial-parallel converter 104.

The grouping means 102 is connected to a plurality of transmitting antenna elements 1011 to 101M and has a function of grouping the plurality of transmitting antenna elements 1011 to 101M into a plurality of groups.
Each of the plurality of transmission diversity signal generators 1031 to 103K is provided corresponding to each of the groups, and generates a signal for performing transmission diversity among the grouped groups.
The serial-parallel converter 104 performs serial-parallel conversion on an input signal to be transmitted, and generates an input signal to each of the plurality of transmission diversity signal generation devices 1031 to 103K provided for each group.

  In the above configuration, first, a transmission signal is input to the serial-parallel converter 104, and K signal sequences are generated by the serial-parallel converter 104, and each of these signal sequences corresponds to a corresponding signal generator for transmission diversity. 1031 to 103K. Transmission diversity is, for example, Space-Time-Transmission-Diversity (Tachikawa's “W-CDMA mobile communication system” Maruzen) or Space-Time-Block-Code (Naguib, et.al “Space-Time-Block-Codes: code design criteria), Delay Diversity, etc. can be used.

The k-th transmission diversity signal generator can be configured to perform transmission diversity of _nk branches, and the number of branches used in each transmission diversity signal generator can be changed. The same antenna element can belong to a plurality of groups. After performing such encoding, the signals of each group grouped by the grouping means 102 are input to the transmitting antenna elements 1011 to 101M and transmitted toward the receiving station.
By transmitting in this way, according to the first embodiment, a diversity effect can be obtained even in an environment with a propagation environment estimation error, and transmission quality can be greatly improved.

[Second Embodiment]
FIG. 2 shows the configuration of a spatial multiplexing transmission apparatus according to the second embodiment of the present invention. The spatial multiplexing transmission apparatus according to the second embodiment improves a transmission quality by estimating a transfer function at the time of reception, selecting an antenna element to transmit using a transfer function estimation result, and performing power distribution. . In FIG. 2, the spatial multiplexing transmission apparatus according to the second embodiment includes a plurality of transmission antenna elements 1011 to 101M having three or more elements, a grouping means 102, transmission diversity signal generation apparatuses 1031 to 103K, The serial-parallel converter 104, the transfer function estimation means 201, and the grouping determination means 202 are provided.

The grouping means 102 is connected to a plurality of transmitting antenna elements 1011 to 101M and has a function of grouping the plurality of transmitting antenna elements 1011 to 101M into a plurality of groups.
Each of the plurality of transmission diversity signal generators 1031 to 103K is provided corresponding to each of the groups, and generates a signal for performing transmission diversity among the grouped groups.

The serial-parallel converter 104 performs serial-parallel conversion on an input signal to be transmitted, and generates an input signal to each of the plurality of transmission diversity signal generation devices 1031 to 103K provided for each group.
The transfer function estimation unit 201 has a function of estimating a propagation environment at the time of reception. That is, a transfer function between each antenna element used by the partner station and each antenna element of the own station is estimated in uplink communication. This transfer function estimation means 201 corresponds to the propagation environment estimation means of the present invention.
The grouping determination unit 202 determines the grouping so that the transmission quality in each group is substantially constant from the transfer function estimation result (propagation environment estimation result) by the transfer function estimation unit 201.

The transfer function estimation means 201 first estimates a transfer function between each antenna element used by the counterpart station and each transmitting antenna element of the own station in uplink communication. The transfer function can be estimated by, for example, transmitting a known signal sequence in advance from the antenna element i of the counterpart station and obtaining a correlation value with the known signal sequence for the signal received by the receiving antenna j. It becomes.
Next, the grouping means 102 groups the transmitting antenna elements 1011 to 101M. The grouping is performed by the following procedure, for example.

  First, a grouping determination unit 202 sets a threshold value of a certain transmission quality, and selects a transmission antenna element that has a transmission quality exceeding the threshold value even when transmitted by one element based on the estimation result of the transfer function estimation unit 201 I do. Next, a set of two elements among the antenna elements for transmission that did not meet the threshold value is formed, and a combination that exceeds the threshold value of transmission quality when transmission diversity is performed between the two elements is selected. If there is an antenna that has not been used even under these conditions, a combination that exceeds the transmission quality threshold when transmission diversity is performed between the three elements is selected. Grouping becomes possible by repeating this selection.

In this way, the grouping determining unit 202 determines the grouping of the transmitting antenna elements 1011 to 101M, and based on this determination, the grouping unit 102 groups the transmitting antenna elements 1011 to 101M.
Furthermore, the transmission quality of each group can be made substantially constant by adjusting the multi-value number of the modulation scheme and the transmission power.
According to the spatial multiplexing transmission apparatus according to the second embodiment, the transmission quality in each group can be made substantially constant by performing the grouping as described above, and the conventional space. It is possible to increase the number of spatial multiplexing and increase the transmission speed without degrading the transmission quality as compared with the multiplex transmission apparatus.

[Third embodiment]
The configuration of the spatial multiplexing transmission apparatus according to the third embodiment of the present invention is shown in FIG. The spatial multiplexing transmission apparatus according to the third embodiment is configured to form multi-beams and apply spatial multiplexing and transmission diversity between the multi-beams.
In FIG. 3, the spatial multiplexing transmission apparatus according to the third embodiment includes a plurality of transmission antenna elements 1011 to 101M having three or more elements, a grouping unit 102, transmission diversity signal generation apparatuses 1031 to 103K, The serial-parallel converter 104, the transfer function estimation unit 201, the grouping determination unit 202, and the multi-beam forming device 301 are included.

In the above configuration, the transmission signal is input to the serial-parallel converter 104, and the input signal to the transmission diversity signal generation devices 1031 to 103K is generated.
Transmission diversity is, for example, Space-Time-Transmission-Diversity (Tachikawa's “W-CDMA mobile communication system” Maruzen) or Space-Time-Block-Code (Naguib, et.al “Space-Time-Block-Codes: code design criteria), Delay Diversity, etc. After such encoding, grouping by the grouping unit 102 is performed based on the determination of the grouping determination unit 202 as in the second embodiment described above. Each group of signals is input to the multi-beam forming apparatus 301.

Here, in the multi-beam forming apparatus 301, N beams are formed by the following procedure.
First, the multi-beamforming apparatus 301 performs singular value decomposition (H = UDVH) of the transfer function matrix H obtained from the estimation result of the transfer function estimating means 201, and converts the M-unit M matrix unitary matrix V and the singular value into elements. A diagonal matrix D of N rows and M columns is obtained. In the singular value decomposition, the same number of singular values as the number of transmitting antennas and column vectors v1 to vM of the unitary matrix V corresponding to each singular value are obtained. Column vectors v1 to vM each represent the directivity of the beam formed during transmission. Therefore, using the column vectors v1 to vM, N beams can be formed simultaneously. The multi-beam forming apparatus 301 corresponds to the multi-directional pattern forming apparatus of the present invention.

The grouping unit 102 groups N beams formed by the transmitting antenna elements 1011 to 101M. The grouping is performed by the following procedure, for example. The grouping determination unit 202 first sets a threshold value of a certain transmission quality (singular value), and selects a beam having a transmission quality exceeding the threshold value even when transmitted with one beam .

Next, among the beams that do not satisfy the threshold, a pair of two beams is formed, and a combination that exceeds the transmission quality threshold when transmission diversity is performed between the two beams is selected. If there is a beam that is not yet used even under this condition, a combination that exceeds the transmission quality threshold when transmission diversity is performed between three beams is selected. Grouping becomes possible by repeating this selection.
In this way, the grouping determining means 202 determines the grouping of N beams formed by the transmitting antenna elements 1011 to 101M , and based on this determination, the grouping means 102 determines the transmitting antenna elements 1011 to 101M. The N beams formed in the above are grouped.

Furthermore, the transmission quality of each group can be made substantially constant by adjusting the multi-value number of the modulation scheme and the transmission power.
The total number of beams thus selected is N, and the signal series for transmission diversity generated for each group is represented as E _{1 to} E _N.
Multi-beam forming apparatus 301 forms transmission signals S _{1 to} S _M to be transmitted from each transmission antenna from signal sequences E _{1 to} E _N by the following equation.

第３実施形態に係る空間多重伝送用送信装置によれば、上述したように構成することによって、送信局で指向性利得を得るとともに送信ダイバーシチも実現可能となる。

According to the spatial multiplexing transmission apparatus according to the third embodiment, by configuring as described above, it is possible to obtain directivity gain at the transmission station and also realize transmission diversity.

[Fourth embodiment]
The configuration of the spatial multiplexing transmission apparatus according to the fourth embodiment of the present invention is shown in FIG. The spatial multiplexing transmission apparatus according to the fourth embodiment has a configuration in which the transmission power of each group is variable.
In FIG. 4, the spatial multiplexing transmission apparatus according to the fourth embodiment includes a plurality of transmission antenna elements 1011 to 101M having three or more elements, a grouping means 102, transmission diversity signal generation apparatuses 1031 to 103K, Serial-parallel converter 104, transfer function estimating means 201, grouping determining means 202, and transmission power varying means 401 are provided.

  The transmission power varying means 401 has a function of allocating transmission power to each group of transmitting antenna elements so that the average error rate of signals transmitted from each group of transmitting antenna elements is minimized. The transmission power variable means 401 corresponds to the transmission power allocation means of the present invention.

In the above configuration, the transmission signal is input to the serial-parallel converter 104, and the serial-parallel converter 104 performs serial-parallel conversion to generate an input signal to the signal generators 1031 to 103M for transmission diversity.
Transmission diversity is, for example, Space-Time-Transmission-Diversity (Tachikawa's “W-CDMA mobile communication system” Maruzen) or Space-Time-Block-Code (Naguib, et.al “Space-Time-Block-Codes: code design criteria), Delay Diversity, etc. can be used.

  After such encoding, the signals of each group grouped by the grouping means 102 are input to the transmission power variable means 401, and after changing the transmission power, they are input to the transmission antenna elements 1011 to 101M. , Transmitted toward the receiving station. Here, the transmission power varying means 401 weights the transmission signal according to the transmission quality. That is, in each of the transmitting antenna elements 1011 to 101M, transmission power is allocated to each group of transmitting antenna elements so that the average error rate of signals transmitted from each group of transmitting antenna elements is minimized.

  According to the spatial multiplexing transmission apparatus according to the fourth embodiment, by operating as described above, the transmission power of a signal with degraded transmission quality is increased, and the transmission power for a signal with excessive transmission quality is increased. And the error rate characteristics can be improved.

[Fifth Embodiment]
The configuration of the spatial multiplexing transmission apparatus according to the fifth embodiment of the present invention is shown in FIG. The spatial multiplexing transmission apparatus according to the fifth embodiment has a configuration in which the transmission power of each group of transmission antenna elements is variable, and the spatial multiplexing transmission apparatus according to the fourth embodiment, The difference is that a multi-beam forming device is added between the transmitting antenna elements 1011 to 101M and the transmission power variable means 401, and the other configuration is the spatial multiplexing transmission according to the fourth embodiment. It is the same as that of the transmitter for use.

  5, the spatial multiplexing transmission apparatus according to the fifth embodiment includes a plurality of transmission antenna elements 1011 to 101M having three or more elements, a grouping unit 102, transmission diversity signal generation apparatuses 1031 to 103K, The serial-parallel converter 104, the transfer function estimation unit 201, the grouping determination unit 202, the transmission power variable unit 401, and the multi-beam forming device 301 are provided.

  According to the spatial multiplexing transmission apparatus according to the fifth embodiment, by installing the multi-beam forming apparatus 301 between the transmission power varying means 401 and the transmitting antenna elements 1011 to 101M as shown in FIG. Control of transmission power for each signal can be performed even when multi-beams are formed.

  The effect of the present invention will be shown by computer simulation. The number of antenna elements in the transmitting station is 8, the number of antenna elements in the terminal station is 2, and the number of beams in the spatial multiplexing transmission apparatus according to the present invention is 3. The eigenvector beams for the second and third eigenvalues are Used to perform transmission diversity.

FIG. 7 shows a propagation environment used when the transmission characteristics are evaluated by comparing the present invention with the conventional example. As seen from the transmitting station 500 and the terminal station 600, it is assumed that there are a plurality of clusters 700 made up of a large number of scatterers, and the propagation path is the cluster 700 around the transmitting station 500 and the cluster 700 around the terminal station 600. Each is configured by reflection.
[1] Wataru Yamada, Naoki Kita, Akio Sato, Tetsuya Takao, Daisuke Mori, Hironobu Watanabe,
“Microwave angle spread characteristics in indoor environments”, IEICE Communication Society, B-1-54, 2003
In [1], the result of indoor measurements shows that there are five lumps of incoming waves and the angular spread of the distribution is about 25 °. The angle spread was 25 °.

The transfer function between each antenna and the base station antenna in the uplink can be estimated without error, only the angle spread is the same in the uplink and downlink, and the arrival direction and arrival phase of the wave are set independently.
The number of trials was 10,000. In the conventional method, singular value decomposition is performed from the estimated transfer function, and SDM transmission is performed using two eigenvectors from the larger eigenvalue.

FIG. 6 shows the average error rate characteristics for the transmission signal transmitted using the second eigenvector beam when the transmission power is changed, comparing the present invention (proposed method) and the conventional method. The noise level at each terminal station antenna was 0 dB. The transmission diversity effect between two beams in the present invention over conventional methods, approximately 2.5dB on average error rate of 10 ^-3, is that the transmission characteristic by about 5dB at an average error rate of ^10-4 is improved understood.

The block diagram which shows the structure of the transmitter for spatial multiplexing transmission which concerns on 1st Embodiment of this invention. The block diagram which shows the structure of the transmitter for spatial multiplexing transmission which concerns on 2nd Embodiment of this invention. The block diagram which shows the structure of the transmitter for spatial multiplexing transmission which concerns on 3rd Embodiment of this invention. The block diagram which shows the structure of the transmitter for spatial multiplexing transmission which concerns on 4th Embodiment of this invention. The block diagram which shows the structure of the transmitter for spatial multiplexing transmission which concerns on 5th Embodiment of this invention. The figure which showed the error rate characteristic with respect to the transmission signal at the time of changing the transmission power in the transmitter for spatial multiplexing transmission which concerns on embodiment of this invention compared with the prior art example. Explanatory drawing which shows the propagation environment used when comparing the transmission apparatus for spatial multiplexing transmission which concerns on this invention, and a prior art, and evaluating a transmission characteristic. The block diagram which shows an example of a structure of the transmission apparatus for conventional spatial multiplexing transmission. The block diagram which shows the other example of a structure of the transmission apparatus for conventional spatial multiplexing transmission.

Explanation of symbols

Reference numerals 1011 to 101M: antenna elements for transmission 102: grouping means 1031 to 103K: signal generator for transmission diversity 104: serial-parallel converter

Claims (5)

At least three transmitting antenna elements;
A grouping means connected to each transmitting antenna element for grouping the transmitting antenna elements into a plurality of groups;
A plurality of transmission diversity signals provided corresponding to each group for generating a signal for performing transmission diversity when there are a plurality of transmission antenna elements constituting each group among the grouped groups. A generating device;
A serial-parallel converter that serial-parallel converts an input signal to be transmitted, and generates an input signal to the plurality of transmission diversity signal generation devices provided for each group;
Propagation environment estimation means for estimating propagation environment at the time of reception;
A transmission quality threshold value is set in advance, and based on the propagation environment estimation result by the propagation environment estimation means , the grouping is determined so as to form a group with one or more transmitting antenna elements exceeding the threshold value with the smallest number of elements. A grouping determination means,
The spatial group transmission apparatus according to claim 1, wherein the grouping unit performs grouping based on the determination by the grouping determination unit. Wherein as the mean error rate of the signal transmitted by each group of transmitting antennas is minimized, according to claim 1, characterized in that a transmission power allocation means for allocating transmission power to each group of said transmit antenna Transmitter for spatial multiplexing transmission. M (M ≧ 3) transmitting antenna elements;
A multi-directional pattern forming device connected to each of the transmitting antenna elements and forming N beams using the transmitting antenna elements;
A grouping unit connected to an input unit of the multi-directional pattern forming device and grouping the N beams into a plurality of groups;
A plurality of transmission diversity signal generation devices provided corresponding to each group for generating a signal for performing the transmission diversity when a plurality of the beams constituting each group among the divided groups are provided When,
A serial-parallel converter that serial-parallel converts an input signal to be transmitted, and generates an input signal to the plurality of transmission diversity signal generation devices provided for each group;
Propagation environment estimation means for estimating propagation environment at the time of reception;
A grouping decision that sets a transmission quality threshold value in advance and determines the grouping so as to configure one or more beam groups exceeding the threshold value with the smallest number of elements based on the propagation environment estimation result by the propagation environment estimation means Means,
The spatial group transmission apparatus according to claim 1, wherein the grouping unit performs grouping based on the determination by the grouping determination unit. In the multi-pattern directivity forming device, each beam is an eigen beam obtained from singular value decomposition of a transfer function matrix,
In the grouping determination means, a beam having a value equal to or higher than a preset threshold value corresponding to the eigen beam is set as a transmission beam,
4. The spatial multiplexing transmission apparatus according to claim 3 , wherein in each grouping, groups are determined so that sums of singular values in each group are substantially equal. 5. The spatial multiplexing transmission according to claim 4, further comprising transmission power allocating means for allocating transmission power to each group so that an average error rate of signals transmitted in each group of eigenbeams is minimized. Transmitter.

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