JP2008098940A - Transmission method and transmitter for spatial multiplex transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission method and a transmitter for spatial multiplex transmission for easily determining the combination of one or more communicating parties in the case that there are a plurality of the communicating parties and different signal sequences are transmitted at the same time and at the same frequency band to one or more communicating parties from them. <P>SOLUTION: The method for spatial multiplex transmission when a plurality of antenna elements are provided and signals are transmitted to the plurality of communicating parties at the same time and at the same frequency band comprises: a step of computing a transmission space vector group for each communicating party for performing communication; a step of computing inner product values of the transmission vector groups of the different communicating parties; and a step of selecting the communicating parties whose inner product values are small as opposite stations to perform simultaneous transmission. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-speed wireless access system that uses the same frequency channel, spatially multiplexes independent signal sequences from a plurality of different transmission antennas, transmits the signal sequences to a plurality of communication partners, and realizes information transmission to the plurality of communication partners. The present invention relates to a transmission method and a transmission device for spatial multiplexing transmission for selecting a communication partner for spatial multiplexing.

  In recent years, the IEEE802.11g standard, the IEEE802.11a standard, etc. have been remarkably spread as high-speed wireless access systems using the 2.4 GHz band or the 5 GHz band. In these systems, an orthogonal frequency division multiplexing (OFDM) modulation scheme, which is a technique for stabilizing characteristics in a multipath fading environment, is used, and a maximum transmission rate of 54 Mbps is realized. However, the transmission rate here is the transmission rate on the physical layer, and the transmission efficiency in the MAC (Medium Access Control) layer is actually about 50 to 70%, so the upper limit of the actual throughput is It is about 30Mbps. On the other hand, in the world of wired LANs, the provision of 1OOMbps high-speed lines has become widespread due to the widespread use of Ethernet (registered trademark) 100Base-T interface and FTTH (Fiber to the home) using optical fiber in each home. In the world of wireless LAN, further increase in transmission speed is demanded.

  As a technology for that purpose, Block Diagination (BD) directivity control method is effective. With this BD directivity control method, the transmitting station transmits different independent signals on the same channel from a plurality of transmission antennas to a plurality of communication partners, and the reception beam formed by the reception weights of the communication partners. In this case, a null is formed, a signal is received on the receiving station side without causing interference from other communication partners, a received signal is estimated independently by each communication partner, and data is reproduced.

M _T , the number of communication counterparts Mu, the number of reception antenna elements of the i-th communication counterpart M _R (i) An example of a method of determining a communication partner with the number L (i) and M _T ≧ M _R (i) will be described. FIG. 15 is a configuration example of a BD directivity control method in the prior art in which transmission directivity is controlled so as to be optimal for a propagation environment and spatial multiplexing is performed to improve a transmission rate.
Code 900 data dividing circuit, 901-I~901-L modulation circuit, the transmission signal conversion circuit 902, 903-1~903-M _T wireless unit, 904-1~904-M _T is the antenna element, 905 Is a communication quality evaluation communication partner selection circuit, and 906 is a channel response matrix acquisition circuit.

The antennas (904-1 to 904-M _T ) and the radio units (903-1 to 903-M _T ) can transmit and receive radio signals, and via these antennas (904- 1 to 904-M _T ) and each communication partner antenna can be estimated by the channel response matrix acquisition circuit (906). The method for acquiring this channel response matrix is not specified here, but is estimated based on information obtained when a known signal is received at the antenna (904-1 to 904-M _T ) or included in the received signal. The information of the channel response matrix is acquired by the information included in the feedback information. This information is input to the communication quality evaluation communication partner selection circuit (905), and the transmission weight of each signal series at each antenna is calculated.

Next, when data to be transmitted is input, the data dividing circuit (900) divides one system of signals into L signal series and inputs the signals to the modulation circuits 901-1 to 901-L. Here, a preamble signal or the like for MIMO channel estimation is given and modulated, and these signals are input to the transmission signal conversion circuit (902). Here, the transmission data is multiplied by a transmission weight, is input to the radio section (104-1~104-M _T), is transmitted as a radio signal via an antenna (105-1~105-M _T).

The channel response matrix Hi (M _R (i) XM _T matrix) representing the channel information for the i-th communication partner obtained in the channel response matrix acquisition circuit is obtained by singular value decomposition as shown in the following equation, and the right singular matrix vi (M Matrix D (M _{R ( T} XM _T matrix), left singular matrix Ui (M _R (i) XM _R (i) matrix) and square root of eigenvalue √λ as diagonal elements and non-diagonal matrix O as diagonal elements _i) XM _T matrix).

Here, H _{i, jk} represents a transfer coefficient from the k-th antenna of the transmission device to the j-th antenna at the i-th communication partner. Of the right singular matrix Vi, V′i is a column vector group corresponding to the eigenvalue, and V ″ i is a column vector group corresponding to 0. In communication for a single user, the signal power that can be expressed by the corresponding eigenvalue λi can be obtained by using the column vector of V′i as the transmission weight. (λ ₁ ≧ λ ₂ ≧... ≧ λ _{MR (i)} ). Here, the superscript H represents a conjugate complex matrix.

と表す。ここでl(i)は、l番目のタイミングで同時に送信する通信相手の中でi番目の通信相手の番号のことである。Rl(j)はl(i)番目の通信相手に仮定した受信ウエイトであり、対角行列とすれば、受信ウエイトの仮定なしの条件となる。このH⁺ _l(i)(ｌ)に対し、特異値分解を行うと、

と表すことができ、Ｖ^＋ _l(i)(l)は国有値D^- _l(i)(l)に対応するベクトルであり、Ｖ⁻ _l(i)(l)は固有値がない、もしくは固有値０に対応するヌル空間ベクトルである。ここで、Ｖ⁻ _l(i)(l)の送信空間に対し、送信を行うと、l番目のタイミングにおけるｌ(i)以外の通信相手の受信ウエイトに対し、干渉を生じない。そこで、この送信空間において得られる通信品質を評価するには、l(i)番目の通信相手のチャネル応答行列に対し、このヌル空間ウエイトＶ⁻ _l(i)(l)を乗算して得られる行列の特異値を計算すればよい。

The means of the communication partner selection method by BD method with respect to a multiuser is shown. Here, it is considered that among Mu communication partners who want to perform communication, block is made for each communication partner of Mu ′ (l), and transmission is simultaneously performed to the plurality of communication partners at the l-th timing. It is assumed that the communication partner number iεU (l) to be transmitted at the l-th timing. Here, a method for evaluating the transmission quality when transmitting to the Mu ′ (l) communication partners by the BD method is shown.
An evaluation method of the transmission capacity achievable by the i'th communication partner among the communication partners of Mu '(l) is shown.
First, among Mu '(l) communication partners that simultaneously transmit H ⁺ _{l (i)} (l) at the l-th timing in the same frequency band, channels of communication partners other than the l (i) -th communication partner A set matrix of response matrices,

It expresses. Here, l (i) is the number of the i-th communication partner among the communication partners that transmit simultaneously at the l-th timing. Rl (j) is a reception weight assumed for the l (i) -th communication partner. If a diagonal matrix is used, Rl (j) is a condition without assumption of reception weight. When singular value decomposition is performed on this H ⁺ _{l (i)} (l),

V ⁺ _{l (i)} (l) is a vector corresponding to the national value D ^- _{l (i)} (l) and V ^- _{l (i)} (l) has no eigenvalue or eigenvalue A null space vector corresponding to zero. Here, when transmission is performed in the transmission space of V ⁻ _{l (i)} (l), no interference occurs with the reception weight of the communication partner other than l (i) at the l-th timing. Therefore, in order to evaluate the communication quality obtained in this transmission space, it is obtained by multiplying the channel response matrix of the l (i) th communication partner by this null space weight V ⁻ _{l (i)} (l). What is necessary is just to calculate the singular value of a matrix.

The quality corresponding to the null space eigenvalue, λ _j ^o , which is the square value of the diagonal component of D ^o _{l (t)} (l), is obtained. However, there are _Mu C _{Mu '(l)} combinations of these communication partners for each possible Mu' (l). To calculate the null space eigenvalue for each communication partner using the above method for each combination. Enormous calculation is required.
QH Spencer, AL Swindlehurst, and M. Haardt, “Zero-Forcing Methods for Downlink Spatia1 Multiplexing in Multiuser MIMO Channels,” IEEE Trans. Sig. Processing, vol. 52, issue 2, Feb. 2004, pp. 461-71.

  However, although the above-described means makes it possible to obtain a high transmission capacity by spatial multiplexing in the same time and the same frequency band for a plurality of communication partners, a very large calculation amount is required for determining the combination of communication partners. There is a problem you need.

  The present invention has been made in view of such circumstances, and there are a plurality of communication partners, and when different signal sequences are transmitted at the same time and the same frequency to one or more communication partners among them. Another object of the present invention is to provide a spatial multiplexing transmission method and transmission device that can easily determine a combination of one or more communication partners.

  In order to solve the above-described problems, the present invention provides a spatial multiplexing transmission method for transmitting signals to a plurality of communication partners at the same time and the same frequency band, and including a plurality of antenna elements. A step of calculating a transmission space vector group for each communication partner to be performed, a step of calculating a norm of inner product values of transmission vector groups of different communication partners, and communication in which the norm of one or more obtained inner product values is reduced Selecting the other party as a partner station to transmit the other party at the same time.

  Further, the present invention is a spatial multiplexing transmission method for transmitting signals to the same frequency band at the same time for a plurality of communication partners, including a plurality of antenna elements, and for each communication partner performing communication, A step of calculating a unit vector corresponding to the eigenvalue of the right singular matrix of the channel response matrix, and a step of calculating a norm of inner product values of vectors corresponding to the eigenvalues of the right singular matrix used for transmission of different communication partners. Selecting a communication partner having a smaller norm of one or more inner product values as a partner station for simultaneous transmission.

  Further, the present invention is the above-described transmission method for spatial multiplexing transmission, wherein when three or more communication partners are selected, a step of calculating a transmission space vector group for two or more already selected communication partners; A step of calculating a norm of inner product values of a transmission space vector group of a selected communication partner and a transmission space vector group of another communication partner, and a communication partner whose norm of the obtained one or more inner product values is reduced And a step of selecting a new one.

  The present invention also provides a method of selecting a communication partner that includes a plurality of antenna elements and transmits signals to a plurality of communication partners in the same frequency band at the same time, and includes a transmission space vector of the selected communication partner. A step of calculating a group, a step of calculating an inner product value of a transmission space vector group of a communication partner and a transmission space vector group of another communication partner, and a diagonal having zero as a diagonal element and a constant as a diagonal element A step of calculating a determinant of a matrix obtained by subtracting a matrix composed of the obtained inner product values from the matrix, and a step of selecting communication partners with which the obtained determinant becomes larger, To do.

  The present invention also provides a method of selecting a communication partner that includes a plurality of antenna elements and transmits signals to a plurality of communication partners in the same frequency band at the same time, and includes a transmission space vector of the selected communication partner. A step of calculating a group, a step of calculating, for each communication partner, a total transmission space vector group formed in a communication partner other than the communication partner, a transmission space vector group of each communication partner, and other than the communication partner Matrix matrix obtained by subtracting the matrix of the obtained inner product values from the step of calculating the inner product value of all transmission space vectors, and a diagonal matrix in which the elements other than the diagonal elements are 0 and the diagonal elements are constants A step of calculating an expression, a step of calculating an evaluation value from the obtained one or more determinants and the number of streams formed in each communication partner, and a combination of communication partners having the largest evaluation value obtained Characterized in that it comprises the steps of-option, a.

In addition, the present invention can transmit a single or a plurality of signal sequences spatially multiplexed at the same frequency channel and the same time from a transmission device having a plurality of antenna elements to a plurality of communication partner stations. A wireless transmission apparatus in a wireless communication system includes M _T (M _T > 1: integer) antenna elements and is connected to each of the antenna elements, and converts a received signal into a baseband signal at the time of reception. Output to the acquisition circuit, and at the time of transmission, estimate the channel information for the communication partner from the radio unit that transmits the transmission signal as a radio signal from the antenna element and the signal input from the radio unit, and output to the transmission space vector arithmetic circuit Based on the channel information acquisition circuit and the channel information input from the channel information acquisition circuit. Calculating a norm of inner product values between different communication partners with respect to a transmission space vector group input from the transmission space vector arithmetic circuit and the transmission space vector arithmetic circuit; An inner product value calculation selection circuit for selecting the smallest combination, a communication partner selection block including the channel information acquisition circuit, a transmission space vector calculation circuit, and an inner product value calculation circuit, and the transmission data as the number of communication sequences. A data division circuit that divides in response, a modulation circuit that modulates each signal sequence of the data divided by the data division circuit, and a transmission determined by a transmission weight calculation circuit for each communication sequence modulated by the modulation circuit A transmission signal conversion circuit that multiplies the weight and outputs to a radio unit connected to a corresponding antenna element, That.

In addition, the present invention can transmit a single or a plurality of signal sequences spatially multiplexed at the same frequency channel and the same time from a transmission device having a plurality of antenna elements to a plurality of communication partner stations. A wireless transmission apparatus in a wireless communication system includes M _T (M _T > 1: integer) antenna elements and is connected to each of the antenna elements, and converts a received signal into a baseband signal at the time of reception. Output to the acquisition circuit, and at the time of transmission, estimate the channel information for the communication partner from the radio unit that transmits the transmission signal as a radio signal from the antenna element and the signal input from the radio unit, and output to the transmission space vector arithmetic circuit And a right singular matrix of the transmission side correlation matrix based on the channel information input from the channel information acquisition circuit. The transmission space vector arithmetic circuit to calculate and the right singular matrix inputted from the transmission space vector arithmetic circuit calculates the norm of the inner product value between different communication partners, and the norm of one or a plurality of inner product values obtained is calculated. An inner product value calculation selection circuit for selecting the smallest combination, a communication partner selection block configured with the channel information acquisition circuit, a transmission space vector calculation circuit, and an inner product value calculation circuit, and a method for modulating transmission data to the number of communication sequences A data dividing circuit that divides the data according to the data dividing circuit, a modulation circuit that modulates each signal sequence of the data divided by the data dividing circuit, and a transmission weight calculation circuit that determines each communication sequence modulated by the modulation circuit. A transmission signal conversion circuit that multiplies transmission weights and outputs to a radio unit connected to a corresponding antenna element. That.

  Further, the present invention is the above-described wireless transmission device, wherein the communication partner selection block estimates channel information for the communication partner from a signal input from the wireless unit, and outputs the channel information to a transmission space vector arithmetic circuit A transmission space vector calculation circuit for calculating a transmission space vector group based on channel information input from the channel information acquisition circuit, and a transmission space vector group input from the transmission air vector calculation circuit between different communication partners Subtracts the matrix consisting of the input inner product values from the inner product value arithmetic circuit that calculates the inner product value in and outputs the result to the determinant arithmetic comparison circuit and the matrix in which the diagonal elements are constants and the non-diagonal elements are zero. And a determinant operation comparison circuit that selects a combination in which the obtained determinant is the largest.

  Further, the present invention is the above-described wireless transmission device, wherein the communication partner selection block estimates channel information for the communication partner from a signal input from the wireless unit, and outputs the channel information to a transmission space vector arithmetic circuit And a transmission space vector group for each communication partner based on the channel information input from the channel information acquisition circuit, and a total transmission space vector group for all communication partners selected for each communication partner other than the communication partner. Calculates the inner product value of the transmission space vector calculation circuit that calculates, the transmission space vector group that is input from the transmission space vector calculation circuit, and all the transmission space vector groups that are calculated for the corresponding communication partner, and compares the determinant operation The inner product value calculation circuit to be output to the circuit, and a matrix composed of input inner product values from a matrix in which diagonal elements are constants and non-diagonal elements are zero. Calculated, and wherein the determinant operational comparator circuit evaluation value calculated from the obtained matrix equation selects the most larger combinations, in that they are composed of.

  As described above in detail, according to the present invention, when performing MIMO communication using one or more signal sequences addressed to a plurality of communication partner stations using spatial multiplexing at the same time on the same frequency channel. By selecting an optimal transmission weight combination, it is possible to realize good communication characteristics.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration example of a transmission unit in the first embodiment of the present invention. 100 data dividing circuit, 101-1 to 101-L is the modulation circuit, 102 transmitting signal conversion circuit, 103-1 to 103-M _T wireless unit, 104-1 to 104-M _T antenna, 105 transmission A weight calculation circuit, 106 is an orthogonal space calculation circuit, 107 is a channel response matrix acquisition circuit, and 110 is a transmission weight determination block.

As in the case of the prior art, the antenna (104-1 to 104-M _T ) and the radio unit (103-1 to 103-M _T ) can transmit and receive radio signals, and the radio unit (103 -1 to 103-M _T ), the channel information acquisition circuit (107) receives each antenna (104-1 to 104-M _T ) of the transmission unit and a plurality of communication partners based on the received signal converted in The channel response matrix between the antenna or the received beam can be estimated. The method for acquiring this channel response matrix is not specified here, but it is estimated based on information obtained when a known signal is received at the antenna (104-1 to 104-M _T ) or included in the received signal. The information of the channel response matrix for each communication partner is acquired by the information included in the feedback information.

  When selecting a communication partner, the channel response matrix of the corresponding communication partner is output to the transmission space vector arithmetic circuit (106). In the transmission space vector calculation circuit (106), a transmission space vector group is calculated for each communication partner and output to the correlation value calculation selection circuit (105). In the correlation value calculation selection circuit (105), the inner product value of the transmission space vector is calculated, the combination having the smallest inner product value is selected, and the communication partner corresponding to the data output circuit (100-1) is designated. Here, when the inner product value is calculated, the norm of the inner product value is calculated, and the combination that minimizes the norm of the inner product value is selected.

Transmission data is input from the data output circuit (100-1) to the data dividing circuit (100-2), divided into L signal series, and input to the modulation circuits 101-1 to 101-L. Here, after a preamble signal or the like for MIMO channel estimation is given and modulated, these signals are input to the transmission signal conversion circuit (102). Here, the transmission data is multiplied by a transmission weight, is input to the radio section (103-1~103-M _T), is transmitted as a radio signal via an antenna (104-1~104-M _T).

The selection method is shown below. The channel response matrix acquisition circuit performs an orthogonalization method on the row vectors of the matrices H _l ^{* to} H _MU ^* made of conjugate complex numbers of the channel matrices H _{l to} H _Mu for each input communication partner, and transmits the transmission space basis Find a vector group. If the α-th row vector of H _i ^* is g _{i, a} , the transmission space basis vectors e _i.1 , e _i.2 ,... E _{i.MR (i)} for the i-th communication partner are calculated. The

と表すことができる。この相関評価値から、内積値演算選択回路は組み合わせるべき２通信相手を選択するかもしくは複数の通信相手に送信をしないかを選択する。（請求項１）
また、送信空間ベクトルE_iとしてチャネル応答行列Hiを特異値分解することで得られる右特異行列のうち固有値に対応するベクトル群V’iを用いることもできる。（請求項２）
相関評価値の特性について示す。ここで、もともとのi番目の通信相手のj番目の固有値λ_i,jに対し、数４から得たｉ番目の通信相手のj番目の直交空間固有値λ^o _i,jを

と表すことにする。0≦ai,j≦1となっている。
ここで、送信アンテナ素子数をMt、通信相手の受信アンテナ数がすべて１だった場合を考える。このとき、各通信相手との間に形成されるチャネルの固有値および送信空間ベクトルは１つしか存在せず、相関評価値はこの一つのベクトル同士の内積値となる。相関評価値は直交空間を求める際に削除される空間を表しており、相関評価値とａの間には

が成り立つ。よって相関評価値から容易に直交空間での伝送品質を推定可能である。 Here, (a, b) represents the inner product value of the vectors a and b. E _i = [e _{i, 1} ^T , e _{i, 2} ^T ,..., E _{i, MR (i)} ^T ] ^T is a transmission space vector group for the i-th communication partner.
The obtained E _i is output to the inner product value calculation selection circuit (105). Here, the multiplications of the row vectors constituting E _i are evaluated by different communication partners. The evaluation value Γ _αβ of the α th communication partner and the β th communication partner is

It can be expressed as. From this correlation evaluation value, the inner product value calculation selection circuit selects whether to select two communication partners to be combined or not to transmit to a plurality of communication partners. (Claim 1)
Further, the vector group V′i corresponding to the eigenvalues in the right singular matrix obtained by singular value decomposition of the channel response matrix Hi can also be used as the transmission space vector E _i . (Claim 2)
It shows about the characteristic of a correlation evaluation value. Here, with respect to the j-th eigenvalue λ _{i, j} of the original i-th communication partner, the j-th orthogonal space eigenvalue λ ^o _{i, j} of the i-th communication partner obtained from Equation 4 is

It will be expressed as 0 ≦ ai, j ≦ 1.
Here, consider the case where the number of transmitting antenna elements is Mt and the number of receiving antennas of the communication partner is all one. At this time, there is only one eigenvalue and transmission space vector of the channel formed with each communication partner, and the correlation evaluation value is an inner product value of the one vector. The correlation evaluation value represents the space that is deleted when obtaining the orthogonal space, and between the correlation evaluation value and a

Holds. Therefore, the transmission quality in the orthogonal space can be easily estimated from the correlation evaluation value.

シングルユーザMIMOの伝送容量は同様に

と表すことができる。σ²は熱雑音の分数値である。L_αとL_βはそれぞれデータストリーム数である。マルチユーザMIMOがシングルユーザMIMO通信に対し、通信速度や通信品質が高くなる通信相手を組み合わせて、マルチユーザに対し同時送信を行うことにより、高い伝送速度が実現できる。マルチユーザMIMOを行った際にシングルユーザに対する伝送容量の増大度は

と表すことができる。このＲが高い値をとる通信相手を選択することで、システム全体の周波数利用効率が高められる。数１１においてλi,j≧ai,jλi,j≫１と仮定すると、数１１は、

と書き直すことができる。ここで、Ｒは固有値の変化量ａに大きく影響されていることが分かる。
ここで図３に送信素子数を２とし、受信素子数が１である通信相手をランダムに発生させ、Ｒと相関評価値の対応をプロットした結果を示す。平均受信ＳＮＲを30dBとしたものであり、チャネルはi.i.d.で与えた。相関評価値Γからａは一意に決まるにもかかわらず、値がばらついているのは、試行ごとに固有値λが変化しているためである。同様に送信素子数を８とし、受信素子数を１とした場合を図４に示す。送信素子数を増やすと、送信ダイバーシチの効果により、ばらつきが減少し、且つΓが小さい領域に分布がシフトすることがわかる。送信素子数が多いほど、相関評価値による通信相手の選択がしやすくなることを示している。 As an evaluation index of the transmission speed, for example, the transmission capacity of multi-user MIMO can be defined for the α th communication partner and the β th communication partner as follows from the signal-to-noise ratio at the time of decoding on the receiving side.

Single user MIMO transmission capacity is the same

It can be expressed as. σ ² is a fractional value of thermal noise. L _α and L _β are the number of data streams, respectively. A multi-user MIMO can achieve a high transmission rate by simultaneously transmitting to a multi-user by combining communication partners whose communication speed and communication quality are higher than single-user MIMO communication. When multi-user MIMO is performed, the increase in transmission capacity for single users is

It can be expressed as. By selecting a communication partner having a high value of R, the frequency utilization efficiency of the entire system can be improved. Assuming that λi, j ≧ ai, jλi, j >> 1 in Equation 11, Equation 11 is

Can be rewritten. Here, it can be seen that R is greatly influenced by the change amount a of the eigenvalue.
Here, FIG. 3 shows the result of plotting the correspondence between R and the correlation evaluation value, with the number of transmitting elements set to 2 and the number of receiving elements set to 1 randomly generated. The average received SNR was 30 dB, and the channel was given by iid. Although a is uniquely determined from the correlation evaluation value Γ, the value varies because the eigenvalue λ changes from trial to trial. Similarly, FIG. 4 shows a case where the number of transmitting elements is 8 and the number of receiving elements is 1. It can be seen that when the number of transmission elements is increased, the dispersion is reduced and the distribution is shifted to a region where Γ is small due to the effect of transmission diversity. It shows that the larger the number of transmitting elements, the easier it is to select a communication partner based on the correlation evaluation value.

Next, when the number of receiving elements is fixed to 2 and the average received SNR is set to 30 dB, the relationship between Γ and R is plotted as shown in FIG. In this case, the shape of the distribution varies greatly depending on whether Γ is smaller or larger than 1. When Γ is greater than 1, the null space vector V ^- since it is possible to close to _{l (i)} fully 0 either one of the obtained eigenvalues by multiplying or 0, the transmission capacity at this time is large It has been shown to deteriorate. However, if Γ is 1 or less, R has a spread with respect to Γ, but can be estimated from Γ by an upper bound, a lower bound, or a function that can be defined between them. Even when the number of receiving elements is 2, increasing the number of transmitting elements decreases the dispersion of R with respect to Γ. FIG. 6 shows the results when the number of transmitting elements is eight.

  FIG. 7 shows the correspondence between R and Γ when the number of transmitting elements is 8, the number of receiving elements of one communication partner is 3, and the other is 2, and is applicable even when the number of receiving elements is different. I understand.

  In the case of selecting two or more communication partners, for example, it is assumed that Mu ′ communication partner is selected from all communication partners Mu, and an estimated value of R is obtained from Γ for each of Mu ′, The one that increases the sum of the estimated values can be selected.

Alternatively, after first selecting two communication partners, α and β, the transmission space vectors E _α and E _β required for the two communication partners are again used by the orthogonalization method to obtain the second transmission space vector. E _αβ is obtained, a correlation evaluation value between this E _αβ and the remaining Mu-2 communication partner is obtained, and the communication partner is selected. The transmission partner determination block at this time is shown in FIG. After determining the communication partner in the inner product value calculation comparison circuit (205), the second transmission space vector is obtained in the transmission space vector calculation circuit (206), and further communication partners are selected in the inner product value calculation comparison circuit (205). To do.

In addition, when transmitting to multiple communication partners at the same time, it is easy to be affected by time fluctuations and interference, so at this time, only when the expected R is larger than a certain value, that communication partner is simultaneously transmitted. Can do.
When selecting a communication partner, use the communication partner with the highest priority as a reference, calculate the correlation evaluation value for the combination of the communication partner and the other communication partner, and sequentially select the communication partner that transmits at the same time as the communication partner with the higher priority. You can also decide.
Also, when symmetry is established between the uplink and downlink, the same correlation evaluation value is used to select the combination of transmissions of the communication partner on the uplink, and to instruct the transmission timing to the communication partner, as in the downlink. The effect of increasing frequency utilization efficiency can be obtained.

ここで、簡単のためストリーム数はLi=M_R(i)を仮定している。この仮定により得られる伝送容値は、端末におけるＳＮＲが高く、送信素子数が端末の受信素了数より大きいほど、理論的な最大値に漸近する。
数７および、λi,j≧ai,jλi,j≫１が成り立つと仮定をすると、数１３及び数１４はさらに

ここで、Mu'(l)の通信相手のうちのα番目の通信相手のマルチユーザMIMO通信時の伝送容量、Cm,α...ξ,α、を展開すると、

と表せる。つまり、シングルユーザMIMOの伝送容量および通信相手の数とその受信アンテナ素子数が分かっていれば、Πaを求めれば、マルチユーザMlMOの伝送容量が推定できることとなる。また、通信相手全体では、

と表せる。
次にΠaを推定することを考える。数１５より以下の関係が成り立つ。

数１から数１９を変形すると以下のように表せる。

ここで、U_ｌ（ｉ）がユニタリ行列であり行列式の結果に影響を及ぼさないことと、D_l（ｉ）が固有値の平方根を対角要素とする対角行列であることを利用すると数２０はさらに

と表せる。ここで、数１５と比較すると、Πa_ｌ（ｉ）は以下のように導ける。

ここで、Γ^{α... ξl(i)} ₀₁=V’_l(i) ^HV^- _l(i)としており、α... ξは選択されたMu'(ｌ)の通信相手の番号を示す。よって、det(Γ^{α... ξl(i)} ₀₁Γ^{α... ξl(i)} ₀₁ ^H)を求めることで、直接BD法を用いることなくMU-MIMOの伝送容量を簡易に推定できる。しかし、V^-ｌ_（ｉ）やＨ_l(i)Ｖ⁻ _l(i)の演算をする必要があり、演算量はやや高い。そこで更なる簡易な伝送容量の推定を考える。
まず数３の左辺の行列、(Ｖ⁻ _l(i)(l),Ｖ_l(i)(l))とＶ_l(i)(l)の内積値からなる行列をΓ^{α... ξl(i)} _allと定義すると、

と表すことができる。式中のΣM_R（ｌ（i））は選択された通信相手の全受信アンテナ素子数を表す。ここで、(Ｖ⁻ _l(i)(l),Ｖ_l(i)(l))とＶ_l(i)(l)はユニタリ行列であることから、それらを乗算して得られるΓ^{α... ξl(i)} _allもまたユニタリ行列である。このことから、Γ^{α... ξl(i)} _allの行ベクトルに対して、以下の関係が成り立っている。

よって、この関係からΓ^{α... ξl(i)} ₀₀を用いてΓ^{α... ξl(i)} ₀₁を表すことができ、

が導ける。よって数１７および数１８から、マルチユーザMIMO通信時にα〜ξの通信相手Mu’(l)を選択した際のあるα番目の伝送容量C_{m.α... ξ. α}および、通信相手全体での伝送容量Cmは

と推定することができ、特異値分解を用いてBDアルゴリズムから直接推定するより少ない演算量で推定を行うことができる。必ずしも正確に伝送容量を推定する必要はなく、det(I−Γ^{α... ξl(i)} ₀₀Γ^{α... ξl(i)} ₀₀ ^H)を評価値として用い、この値が大きい通信相手を選択してもよい。ここでΓ^{α... ξl(i)} ₀₀を求めるため必要なV⁺ _l(i)は、特異値分解を行わず、直行化法により数５と同様に求めることもできる。数５では、H_i ^＊のα番目の行ベクトルを
ｇ_i,aとしたが、この代わりに(Ｈ_l(i+1) ^T
,・・・, Ｈ_l(Mu’(l))^Tと定義できるl(i)番目の通信相手全体に定義できるチャネル応答行列全体の行ベクトルを用い得られる基底ベクトル群を用いることができる。
また、特に通信相手のユーザ数が２の場合、例えばα番目とβ番目の通信相手を多重すると考えると、Γ^αβ.α ₀₀＝Γ^αβ.β ₀₀であるため、行列式の演算が少なくてよく、それぞれ

と表すことができる。ここで、det(I-AA^H)=det(I-A^HA)の関係から、

が成り立つことを示す。このように２ユーザの選択は演算量が非常に軽いことから、まず、２通信相手を選択し、組み合わせの通りを絞ってから、２より多い通信相手の組み合わせを考えると効率的である。 FIG. 8 shows a configuration example of a communication partner determination block in the second embodiment of the present invention. Reference numeral 305 denotes an inner product value calculation circuit, 306 a transmission space vector calculation circuit, 307 a channel information acquisition circuit, and 308 a determinant comparison circuit.
When selecting a communication partner, the channel response matrix of the corresponding communication partner is output to the transmission space vector calculation circuit (306). The transmission space vector calculation circuit (306) calculates a transmission space vector group for each communication partner and a total transmission space vector group corresponding to a communication partner other than itself selected as the communication partner, and a correlation value calculation circuit ( 305). In the correlation value calculation selection circuit, for each communication partner, the inner product value of the transmission space vector group and the total transmission space vector group corresponding to the other communication partner is calculated and output to the determinant arithmetic comparison circuit (308). To do. The determinant operation comparison circuit (308) estimates the frequency utilization efficiency from the determinant value of the matrix consisting of the input inner product values and the number of streams formed in each communication partner, and selects the combination that has the greatest effect of MU-MIMO. Select and specify the communication partner corresponding to the data output circuit (100-1).
The selection method is shown below.
First, Equations 9 and 10 can be rewritten as follows for the communication partner of Mu ′ (l).

Here, for simplicity, the number of streams is assumed to be Li = M _R (i). The transmission capacity value obtained by this assumption becomes closer to the theoretical maximum value as the SNR at the terminal is higher and the number of transmission elements is larger than the reception completion number of the terminal.
Assuming that Equation 7 and λi, j ≧ ai, jλi, j >> 1 hold, Equations 13 and 14

Here, when the transmission capacity at the time of multi-user MIMO communication of the α-th communication partner of Mu ′ (l) communication partners, Cm, α ... ξ, α, is expanded,

It can be expressed. That is, if the transmission capacity of single user MIMO, the number of communication partners and the number of receiving antenna elements thereof are known, the transmission capacity of multi-user MlMO can be estimated by obtaining Πa. In addition,

It can be expressed.
Next, consider estimating Πa. From Equation 15, the following relationship holds.

When Equation 1 to Equation 19 are transformed, it can be expressed as follows.

Here, if U _{l (i)} is a unitary matrix and does not affect the result of the determinant, and D _{l (i)} is a diagonal matrix having the square root of the eigenvalue as a diagonal element, a number 20 further

It can be expressed. Here, when compared with Equation 15, Πa _{l (i)} can be derived as follows.

Here, Γ ^{α ... ξl (i)} ₀₁ = V ' _{l (i)} ^H V ^- _{l (i)} , α ... ξ indicates the communication partner number of the selected Mu ′ (l). Therefore, by ^obtaining det (Γ ^{α... Ξl (i)} ₀₁ Γ ^{α... Ξl (i)} ₀₁ ^H ), the transmission capacity of MU-MIMO can be easily estimated without using the direct BD method. However, it is necessary to calculate V ^- l _(i) and H _{l (i)} V ^- _{l (i)} , and the amount of calculation is slightly high. Therefore, further simple estimation of transmission capacity is considered.
First, the matrix on the left side of ^{Equation 3, the} matrix consisting of the inner product values of (V ⁻ _{l (i)} (l), V _{l (i)} (l)) and V _{l (i)} (l), is expressed as Γ ^{α ... ξl (i) If} we define _all ,

It can be expressed as. ΣM _R (l (i)) in the equation represents the total number of receiving antenna elements of the selected communication partner. Here, (V ⁻ _{l (i)} (l), V _{l (i)} (l)) and V _{l (i)} (l) are unitary matrices, and thus Γ ^α obtained by multiplying them ^{. .. ξl (i)} _all is also a unitary matrix. From this, the following relationship holds for the row vector of Γ ^{α... Ξl (i)} _all .

Therefore, from this relationship, Γ ^{α ... ξl (i)} ₀₁ can be expressed using Γ ^{α ... ξl (i)} ₀₀ ,

Can lead. Therefore, from the equations 17 and 18, the α-th transmission capacity C _{m.α... Ξ.α} when the communication partner Mu ′ (l) of _{α to ξ} is selected during multi-user MIMO communication and the entire communication partner Transmission capacity Cm at

Thus, estimation can be performed with a smaller amount of computation than by direct estimation from the BD algorithm using singular value decomposition. It is not always necessary to estimate the transmission capacity accurately. Det (I−Γ ^{α ... ξl (i)} ₀₀ Γ ^{α ... ξl (i)} ₀₀ ^H ) is used as an evaluation value. May be selected. Here, V ⁺ _{l (i)} necessary for ^obtaining Γ ^{α... Ξl (i)} ₀₀ can be ^{obtained in the same manner as Equation 5 without performing} singular value decomposition. In Equation 5, the α-th row vector of H _i ^* is g _{i, a} , but instead of (H _{l (i + 1)} ^T
,..., H _{l (Mu ′ (l)} ) A basis vector group obtained by using row vectors of the entire channel response matrix that can be defined for the l (i) th communication partner that can be defined as ^T can be used.
In particular, when the number of users of the communication partner is 2, for example, ^assuming that the α-th and β-th communication partners are multiplexed, Γ ^αβ.α ₀₀ = Γ ^αβ.β ₀₀ , so there are few determinants. Well, each

It can be expressed as. Where det (I-AA ^H ) = det (IA ^H A)

Indicates that Thus, since the amount of calculation for selecting two users is very light, it is efficient to first select two communication partners, narrow down the combinations, and then consider combinations of more than two communication partners.

  FIG. 9 shows a first transmission flow in the first embodiment of the present invention. Before performing communication, a channel response matrix for a communication partner performing transmission is estimated (S110). A transmission space vector is calculated for each communication partner from the channel response matrix (S111). A correlation matrix obtained by taking the inner product value between correlation space vectors is obtained, and a correlation evaluation value that is a norm value is calculated for each combination (S112). The one with the larger transmission rate ratio with the single user communication estimated from the correlation evaluation value is selected as the communication partner to be transmitted to the same timing and the same frequency band (S113). Transmission data is generated for the selected communication partner (S114). Similarly, communication partners other than the selected communication partner are evaluated for combinations that increase the transmission rate, and transmission is performed sequentially.

  FIG. 10 shows a second transmission flow in the first embodiment of the present invention. Before performing communication, a channel response matrix for a communication partner performing transmission is estimated (S120). A transmission space vector is calculated for each communication partner from the channel response matrix (S121). A correlation matrix obtained by taking the inner product value between correlation space vectors is obtained, and a correlation evaluation value that is a norm value is calculated for each combination (S122). Evaluate whether the ratio of the transmission rate to single-user communication estimated from the correlation evaluation value is greater than the predetermined specified ratio RO (S123), and if it is larger, select it as the communication partner to transmit to the same frequency and the same frequency band (S124). If there is no larger one, it transmits individually without transmitting to the same frequency band with the same timing. Transmission data is generated for the selected communication partner (S125). Similarly, communication partners other than the selected communication partner are evaluated for combinations that increase the transmission rate, and transmission is performed sequentially.

FIG. 11 shows a transmission flow in the second embodiment of the present invention. Before performing communication, a channel response matrix for a communication partner performing transmission is estimated (S21O). The multiplexing number Mu of communication partners to be transmitted in the same timing and the same frequency band is set to 1 which is an initial value (S211). A transmission space vector is calculated for each communication partner from the channel response matrix (S212). A correlation matrix obtained by taking inner product values between the transmission space vectors is obtained, and a correlation evaluation value that is a norm value is calculated for each combination (S213).
Evaluate whether the ratio of the transmission rate to single-user communication estimated from the correlation evaluation value is greater than the predefined ratio RO (S214). (S215). At this time, Mu = Mu + 1 is set, and the number of multiplexing is increased (S216). When the multiplexing number is increased and the process returns to S212, a joint transmission space vector is calculated for the communication partner of the Mu (S212). A correlation matrix obtained by taking the inner product value of the transmission space vector with respect to the joint transmission space vector and the transmission space vector calculated for other communication partners is obtained, and the correlation evaluation value which is the norm value is calculated for each combination (S213). . Evaluate whether the transmission rate ratio with single user communication estimated from the correlation evaluation value is larger than the predetermined ratio RO (S214). Select (S215). At this time, the number of multiplexing is increased as Mu = Mu + 1. Alternatively, when it is determined that the ratio is smaller than the specified ratio RO, transmission data is generated for the selected communication partner with Mu as the number of communication partners (S217). Similarly, communication partners other than the selected communication partner are evaluated for combinations that increase the transmission rate, and transmission is performed sequentially.

  FIG. 12 shows a transmission flow when the number of communication partners of the first transmission flow in the second embodiment of the present invention is 2 at the maximum. Before performing communication, a channel response matrix for a communication partner performing transmission is estimated (S310). A transmission space vector is calculated for each communication partner from the channel response matrix (S311). A correlation matrix obtained by taking inner product values between transmission space vectors is obtained (S312), and a determinant of a matrix obtained by subtracting this matrix from a matrix having a constant diagonal term is calculated (S313). From this determinant result, the communication partner is selected from the estimation results of Equations 28 and 29 and the value of the determinant (S314), and communication by single user MIMO can be selected from the estimated result.

  FIG. 13 shows a first transmission flow in the second embodiment of the present invention. Before performing communication, a channel response matrix for a communication partner performing transmission is estimated (S320). From the channel response matrix, the transmission space vector for each communication partner and the total transmission space vector of the selected communication partner other than the communication partner are calculated (S321). A correlation matrix obtained by taking the inner product value of the transmission space vector and all the transmission space vectors is obtained (S322), and a determinant of a matrix obtained by subtracting this matrix from a matrix having a constant diagonal term is calculated (S323). From this determinant result, the communication partner is selected from the estimation results of Equations 26 and 27, the value of the determinant, and the like (S324). Communication by single user MIMO can be selected from the estimated result.

  FIG. 14 shows a second transmission flow in the second embodiment of the present invention. Before performing communication, a channel response matrix for a communication partner that performs transmission is estimated (S330). A transmission space vector is calculated for each communication partner from the channel response matrix (S331). A correlation matrix obtained by taking inner product values between transmission space vectors is obtained (S332), and a determinant of a matrix obtained by subtracting this matrix from a matrix having a constant diagonal term is calculated (S333). From the determinant result, the communication partner is selected from the estimation results of Equations 28 and 29 and the value of the determinant (S334). As a result of the estimation, it is determined whether multi-user MIMO is effective or communication by single-user MIMO is effective in two communication partner multiplexing (S335). If multi-user communication is valid, the characteristics of multi-user MIMO between the two selected communication partners and the additional communication partner are estimated. For any combination of communication partners including two communication partners that have already been selected, the total transmission space vector is calculated from the channel response matrix for the selected communication partner other than the communication partner (S336). A correlation matrix obtained by taking an inner product value with a transmission space vector is obtained (S337), and a determinant of a matrix obtained by subtracting this matrix from a matrix having a constant diagonal term is calculated (S338). From this determinant result, a communication partner is selected from the estimation results of Equations 26 and 27, the value of the determinant, and the like (S339).

At the experimental site in Yokkaichi City, Mie Prefecture, a channel response matrix was obtained with an OFDM signal using 128 subcarriers in the 20 MHz band at a central frequency of 4.85 GHz, and the relationship between the correlation evaluation value and the increase ratio of the transmission capacity is shown in FIG. Plotted on the graph.
As shown in FIG. 16, the correlation evaluation value Γ has a high correlation with the transmission capacity increasing effect even in the actual propagation environment, and the transmission capacity increasing effect is estimated by using the correlation evaluation value in the actual environment. Showed that it is possible.

Moreover, the relationship between the increase ratio of the transmission capacity estimated using the second embodiment of the proposed method and the actual increase ratio of the transmission capacity is plotted in FIG.
As shown in FIG. 17, it can be seen that the transmission capacity increase ratio can be estimated by the proposed method. The reason why the estimation accuracy deteriorates at a low degree of increase is that λi, j ≧ ai, jλi, j >> 1 does not hold and Equations 15 and 16 cannot be assumed. However, in practice, since a communication partner with a high transmission capacity increasing effect is selected, it can be confirmed that the estimation accuracy is high in such a region, which indicates that it is suitable for practical use.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.
Further, by reducing the number of receiving antenna elements of the communication partner to be considered or changing the combination, it can also be used as the receiving antenna element selection of the communication partner by the communication partner selection method using the present invention.
In addition, by using the communication partner selection method using the present invention, it is possible to select a communication partner that communicates simultaneously with the uplink as well as the downlink.

It is a figure which shows the structural example of the transmission part in the 1st Embodiment of this invention. It is a figure which shows the structural example of the communicating party determination block of 1st Embodiment in this invention 1st Embodiment. It is a figure which shows the relationship between the correlation evaluation value in the conditions of 2 transmitting elements in this invention, and 1 receiving element, and a transmission capacity increase degree. It is a figure which shows the relationship between the correlation evaluation value in the conditions of 8 transmission elements in this invention, and 1 reception element, and a transmission capacity increase degree. It is a figure which shows the relationship between the correlation evaluation value in the conditions of 4 transmission elements in this invention, and 2 reception elements, and a transmission capacity increase degree. It is a figure which shows the relationship between the correlation evaluation value in the conditions of 8 elements of transmission, and 2 elements of reception, and a transmission capacity increase degree in this invention. It is a figure which shows the relationship of the correlation evaluation value and transmission capacity increase degree in the conditions of four transmission elements, one receiving three elements, and one receiving two elements in this invention. It is a figure which shows the structural example of the communicating party determination block in the 2nd Embodiment of this invention. It is a figure which shows the 1st transmission flow in the 1st Embodiment of invention. It is a figure which shows the 2nd transmission flow in the 1st Embodiment of this invention. It is a figure which shows the transmission flow in the 2nd Embodiment of this invention. It is a figure which shows the transmission flow when the communicating party of the 1st transmission flow in the 2nd Embodiment of this invention is 2 at the maximum. It is a figure which shows the 1st transmission flow in the 2nd Embodiment of this invention. It is a figure which shows the 2nd transmission flow in the 2nd Embodiment of this invention. It is a figure which shows the transmission part of the 2nd radio station in a prior art. It is a figure which shows the relationship between a correlation evaluation value and a transmission capacity increase degree using the channel response matrix acquired in the outdoor real propagation environment. It is a figure which shows the relationship between the increase ratio of the transmission capacity estimated using 2nd Embodiment of this proposal method, and the increase ratio of an actual transmission capacity.

Explanation of symbols

100-1 data output circuit 100-2 data dividing circuit 101-1 to 101-L modulation circuit 102 transmits the signal conversion circuit 103-1 to 103-M _T radio unit 104-1 to 104-M _T antenna elements 105 and 205 inner product Value arithmetic comparison circuit 106, 206 Transmission space vector arithmetic circuit 107, 207 Channel information acquisition circuit

Claims (9)

A method for spatial multiplexing transmission in which a plurality of antenna elements are provided and signals are transmitted to a plurality of communication partners in the same frequency band at the same time,
Calculating a transmission space vector group for each communication partner performing communication;
Calculating a norm of inner product values of transmission vector groups of different communication partners;
Selecting communication counterparts that simultaneously reduce the norm of one or more obtained inner product values as counterpart stations for simultaneous transmission;
A transmission method for spatial multiplexing transmission, comprising: A transmission method for spatial multiplexing transmission when a plurality of antenna elements are provided and signals are transmitted to a plurality of communication partners in the same frequency band at the same time,
Calculating a unit vector corresponding to the eigenvalue of the right singular matrix of the channel response matrix for each communicating party that performs communication;
Calculating a norm of inner product values of vectors corresponding to eigenvalues of the right singular matrix used for transmission of different communication partners;
Selecting communication counterparts that simultaneously reduce the norm of one or more obtained inner product values as counterpart stations for simultaneous transmission;
A transmission method for spatial multiplexing transmission, comprising: A transmission method for spatial multiplexing transmission according to claim 1 and 2,
When selecting 3 or more communication partners,
Calculating a transmission space vector group for two or more communication partners already selected;
Calculating a norm of an inner product value of a transmission space vector group of a selected communication partner and a transmission space vector group of another communication partner;
Selecting a communication partner for which the norm of one or more inner product values obtained is reduced;
A transmission method for spatial multiplexing transmission, comprising: A method of selecting a communication partner when transmitting signals to the same frequency band at the same time for a plurality of communication partners, comprising a plurality of antenna elements,
Calculating a transmission space vector group of the selected communication partner;
Calculating an inner product value of a transmission space vector group of a communication partner and a transmission space vector group of another communication partner;
Calculating a determinant of a matrix obtained by subtracting a matrix composed of inner product values obtained from a diagonal matrix having a diagonal element other than 0 and a diagonal element as a constant;
Selecting communication partners whose obtained determinant is large;
A communication partner selection method comprising: A method of selecting a communication partner when transmitting signals to the same frequency band at the same time for a plurality of communication partners, comprising a plurality of antenna elements,
Calculating a transmission space vector group of the selected communication partner;
For each communication partner, calculating a total transmission space vector group formed in a communication partner other than the communication partner;
Calculating the inner product value of the transmission space vector group of each communication partner and all the transmission space vectors other than the communication partner;
Calculating a determinant of a matrix obtained by subtracting a matrix composed of inner product values obtained from a diagonal matrix having a diagonal element other than 0 and a diagonal element as a constant;
A step of calculating an evaluation value from the obtained one or more determinants and the number of streams formed in each communication partner;
Selecting a combination of communication partners having the largest evaluation value,
A communication partner selection method comprising: Wireless communication in a wireless communication system capable of spatially multiplexing and transmitting one or a plurality of signal sequences at the same frequency channel and the same time from a transmission device having a plurality of antenna elements to a plurality of communication counterpart stations In the transmission device,
M _T (M _T > 1: integer) antenna elements,
A radio unit connected to each antenna element, converting a received signal to a baseband signal at the time of reception, outputting to a channel information acquisition circuit, and transmitting a transmission signal from the antenna element as a radio signal at the time of transmission;
A channel information acquisition circuit that estimates channel information for a communication partner from a signal input from the wireless unit and outputs the channel information to a transmission space vector arithmetic circuit;
A transmission space vector calculation circuit for calculating a transmission space vector group based on the channel information input from the channel information acquisition circuit;
The transmission space vector group input from the transmission space vector calculation circuit calculates the norm of the inner product value between different communication partners, and selects the smallest combination among the obtained norm of the inner product values. Inner product value calculation selection circuit;
A communication partner selection block configured with the channel information acquisition circuit, the transmission space vector calculation circuit, and the inner product value calculation circuit;
A data division circuit that divides transmission data into the number of communication sequences according to the modulation method;
A modulation circuit that modulates each signal sequence of data divided by the data division circuit;
A transmission signal conversion circuit that multiplies each communication sequence modulated by the modulation circuit by a transmission weight determined by a transmission weight calculation circuit and outputs the result to a radio unit connected to a corresponding antenna element;
A spatial multiplexing transmission apparatus characterized by comprising: Wireless communication in a wireless communication system capable of spatially multiplexing and transmitting one or a plurality of signal sequences at the same frequency channel and the same time from a transmission device having a plurality of antenna elements to a plurality of communication counterpart stations In the transmission device,
M _T (M _T > 1: integer) antenna elements,
A radio unit connected to each antenna element, converting a received signal to a baseband signal at the time of reception, outputting to a channel information acquisition circuit, and transmitting a transmission signal from the antenna element as a radio signal at the time of transmission;
A channel information acquisition circuit that estimates channel information for a communication partner from a signal input from the wireless unit and outputs the channel information to a transmission space vector arithmetic circuit;
Based on the channel information input from the channel information acquisition circuit, a transmission space vector calculation circuit that calculates the right singular matrix of the transmission side correlation matrix;
The inner product that calculates the norm of the inner product value between different communication partners with respect to the right singular matrix input from the transmission space vector operation circuit, and selects the smallest combination among the obtained norms of the inner product values A value calculation selection circuit;
A communication partner selection block configured with the channel information acquisition circuit, the transmission space vector calculation circuit, and the inner product value calculation circuit;
A data division circuit that divides transmission data into the number of communication sequences according to the modulation method;
A modulation circuit that modulates each signal sequence of data divided by the data division circuit;
A transmission signal conversion circuit that multiplies each communication sequence modulated by the modulation circuit by a transmission weight determined by a transmission weight calculation circuit and outputs the result to a radio unit connected to a corresponding antenna element;
A spatial multiplexing transmission apparatus characterized by comprising: The communication partner selection block is:
A channel information acquisition circuit that estimates channel information for a communication partner from a signal input from the radio unit and outputs the channel information to a transmission space vector arithmetic circuit;
A transmission space vector arithmetic circuit that calculates a transmission space vector group based on channel information input from the channel information acquisition circuit;
A transmission space vector group input from the transmission empty vector calculation circuit, calculates an inner product value between different communication partners, and outputs to the determinant calculation comparison circuit,
A determinant operation comparison circuit that subtracts a matrix of input inner product values from a matrix having diagonal elements as constants and non-diagonal elements of 0, and selects a combination having the largest obtained determinant;
The wireless transmission device according to claim 6, comprising: The communication partner selection block is:
A channel information acquisition circuit that estimates channel information for a communication partner from a signal input from the radio unit and outputs the channel information to a transmission space vector arithmetic circuit;
Based on the channel information input from the channel information acquisition circuit, the transmission space vector group for each communication partner and the total transmission space vector group for all communication partners selected other than the communication partner are calculated for each communication partner. A transmission space vector arithmetic circuit,
An inner product value calculation circuit that calculates an inner product value of a transmission space vector group input from the transmission space vector calculation circuit and all transmission space vector groups calculated for the corresponding communication partner, and outputs the inner product value to the determinant calculation comparison circuit;
A matrix that selects the combination with the largest evaluation value calculated from the obtained determinant by subtracting the matrix consisting of the input inner product values from the matrix with diagonal elements as constants and non-diagonal elements as 0 An expression operation comparison circuit;
The wireless transmission device according to claim 6, comprising:

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