JP2012175189A - Radio transmitter, radio receiver, radio communications system, control program, and integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve complexity of a mobile station device, suppress the amount of overhead on a notification from the mobile station device, and improve spatial multiplex occasion by MU-MIMO, relating to a closed loop type MU-MIMO of a codebook base.SOLUTION: The radio transmitter which is equipped with a plurality of transmission antennas, performs pre-coding with the data signal addressed to a plurality of radio receivers respectively, and performs spatial multiplexing with the signal after pre-coding, for transmission. It includes a codebook storage part 101 which stores a first codebook in which a plurality of first linear filters used for pre-coding are described for each of a plurality of groups, a group selection part 103 which selects a plurality of radio receivers that are objects for spatial multiplexing and selects a different group for each of selected radio receivers, and a control information generating part 105 for generating the control information for notifying respective radio receivers of each selected group.

Description

  The present invention relates to a mobile communication technique, and more particularly to a technique for improving the spatial multiplexing opportunity of a mobile station apparatus and suppressing an overhead amount for notification in a codebook-based closed-loop multiuser MIMO.

  In the Long Term Evolution (LTE), which has been standardized in the 3rd Generation Partnership Project (3GPP) as the 3.9th generation wireless transmission system, there are a plurality of wireless transmission systems for improving the frequency utilization efficiency from the third generation wireless transmission system. Multiple Input Multiple Output (MIMO) technology that performs wireless transmission using multiple transmitting and receiving antennas has been specified. With the Spatial Multiplexing (SM) technology, which is one of the MIMO technologies, it is possible to improve the transmission rate without increasing the frequency bandwidth. In addition, LTE-Advanced (LTE-A), an advanced version of LTE, has been approved by the International Telecommunication Union Radio Communications Sector (ITU-R) as one of the fourth generation wireless transmission systems. The standardization activity is actively conducted. In LTE-A, in order to achieve a peak transmission rate of 1 Gbps for downlink (base station device → mobile station device) transmission, single user MIMO (Single User MIMO: SU-MIMO) capable of spatially multiplexing up to 8 streams has been studied. ing. SU-MIMO is MIMO transmission between a base station apparatus having a plurality of transmission antennas and a single mobile station apparatus having a plurality of reception antennas.

  MIMO transmission is roughly classified into closed-loop type MIMO transmission that requires channel state information (CSI) at the transmitter and open-loop type MIMO transmission that does not require CSI. It has been reported that better frequency utilization efficiency can be achieved. However, in the case of a radio communication system based on frequency division duplex (FDD) using different carrier frequencies in the uplink and downlink, in order for the base station apparatus to acquire CSI, it is necessary to feed back CSI from the mobile station apparatus. There is a problem that the overhead is greatly increased.

  Therefore, as described in Non-Patent Document 1, LTE supports codebook-based closed-loop MIMO transmission that can significantly suppress the amount of overhead required for CSI notification. In code-book based closed-loop MIMO, a code book in which a plurality of linear filters are described is shared in advance between a base station apparatus and a mobile station apparatus, and the mobile station apparatus transmits a desired transmission filter from the code book described above. The number is extracted and the base station apparatus is notified of the number (index). The base station apparatus performs MIMO transmission after precoding transmission data based on the notified linear filter. Since the CSI is notified based on the code book, the amount of overhead can be significantly suppressed as compared with the method in which the mobile station apparatus notifies the CSI itself.

  However, in the code book base closed-loop type MIMO transmission, there is a problem that when the number of transmission antennas of the base station apparatus increases, the code book becomes large and the overhead amount increases. Therefore, as in Non-Patent Document 2, precoding is performed using a linear filter that combines two linear filters (W1, W2) described in two types of codebooks, and linear filters selected from the respective codebooks. A method has been proposed in which the time-average overhead amount is suppressed by notifying the base station apparatus of this index at different frequencies.

  On the other hand, multi-user MIMO (MU-MIMO) is a multi-user MIMO (MU-MIMO) that spatially multiplexes transmission signals from a base station device to each mobile station device, considering multiple mobile station devices connected simultaneously as a virtual large-scale antenna array It is supported by LTE, which is also codebook based. Similar to SU-MIMO, in MU-MIMO, the mobile station apparatus notifies a desired linear filter from the code book to the base station apparatus, and the base station apparatus uses a plurality of linear filters notified from a plurality of mobile station apparatuses. It is determined whether or not to perform MU-MIMO for spatially multiplexing and transmitting data addressed to the mobile station apparatus.

  In addition to the desired linear filter, the mobile station apparatus also notifies a best companion PMI (Precoding Matrix Indicator) representing a linear filter most compatible with spatial multiplexing with the desired linear filter in addition to the desired linear filter. A technique called “companion PMI feedback” is discussed in Non-Patent Document 3 and the like. This is because the base station apparatus acquires the desired linear filter and the best companion PMI notified from a plurality of mobile station apparatuses, and spatially multiplexes the mobile station apparatuses in which the desired linear filter is the partner's best companion PMI. Compared with pure codebook-based MU-MIMO, it is possible to improve spatial multiplexing opportunities.

3GPP R1-100501, NTT docomo, “Performance of DL MU-MIMO based on implicit feedback scheme in LTE-Advanced,” Jan. 2010. 3GPP R1-105011, “Way Forward on 8Tx Codebook for Rel.10 DL MIMO,” Aug. 2010. 3GPP R1-090051, Alcatel-Lucent, “UE PMI feedback signaling for user pairing / coordination,” Jan. 2009.

  However, in codebook-based closed-loop MIMO, the mobile station apparatus extracts a desired linear filter from the linear filter group described in the codebook, so that the complexity of the mobile station apparatus increases as the codebook size increases. There was a problem of letting it go. That is, in order for the mobile station apparatus to extract a desired transmission filter, the reception quality (reception signal to noise power ratio (reception SNR), reception signal to interference and noise power ratio (reception) SINR) or communication capacity (capacity), etc., and the results need to be compared, which increases the burden on the mobile station device and increases the complexity.

  Further, the frequency utilization efficiency can be improved by further notifying the linear filter other than the desired linear filter, but there is a problem that the overhead amount for the notification from the mobile station apparatus increases. That is, there is a problem that the overhead amount increases in order to notify the best companion PMI.

  Further, in any case, in MU-MIMO, multiplexing by MU-MIMO is possible only when desired linear filters selected and notified by each mobile station apparatus are orthogonal combinations. There was a problem that spatial multiplexing opportunities were limited. That is, in codebook-based MU-MIMO in which the mobile station apparatus does not notify CSI itself, inter-user interference that occurs between streams addressed to each user in a combination of linear filters notified from each mobile station apparatus (user). There is a problem that (Inter-User Interference: IUI) is sufficiently small, that is, the notified linear filters must be orthogonal or close to orthogonal, and the spatial multiplexing opportunities are limited. .

  The present invention has been made in view of such circumstances, and in codebook-based closed-loop MU-MIMO, the complexity of the mobile station apparatus is improved and the overhead amount related to the notification from the mobile station apparatus is suppressed. And a wireless transmission device, a wireless reception device, a wireless communication system, a control program, and an integrated circuit that realize improvement of spatial multiplexing opportunities by MU-MIMO.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the radio transmission apparatus of the present invention includes a plurality of transmission antennas, performs precoding on data signals addressed to a plurality of radio reception apparatuses, and transmits the precoded signals by spatial multiplexing. A transmission apparatus, wherein a plurality of first linear filters used for precoding store a first codebook described for each of a plurality of groups, and a plurality of spatial multiplexing targets A group selection unit that selects a radio reception device and selects the different group for each selected radio reception device, and a control information generation unit that generates control information for notifying the selected radio reception device of each selected group And.

  In this way, since the wireless transmission device selects a plurality of wireless reception devices to be subjected to spatial multiplexing and selects different groups for each, the number of candidates when the wireless reception device calculates a desired linear filter Can be reduced. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (2) In addition, the wireless transmission device of the present invention further includes an arrival direction estimation unit that estimates an arrival direction of the wireless signal transmitted from the wireless reception device, and the group selection unit transmits from each of the wireless reception devices. A plurality of radio receiving apparatuses to be subjected to spatial multiplexing are selected based on the arrival direction estimation result of the radio signals.

  In this way, since the wireless transmission device selects a plurality of wireless reception devices to be subjected to spatial multiplexing based on the arrival direction estimation results of the plurality of wireless reception devices, the MU-MIMO transmission with higher orthogonality and higher MU-MIMO transmission. It is possible to select a set of wireless reception devices that can achieve efficiency.

  (3) In the wireless transmission device of the present invention, the codebook storage unit stores a second codebook in which a plurality of second linear filters are described, and the first and second linear filters are stored. The precoding is performed using a combined linear filter.

  As described above, since the wireless transmission device further stores the second codebook in which the plurality of second linear filters are described, each of the two types of codebooks, the first codebook and the second codebook, is described. Precoding can be performed by a linear filter obtained by combining the two linear filters. This makes it possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter of the first codebook in the codebook-based closed-loop MU-MIMO, and the desired linearity in the wireless reception device. The amount of calculation required for the calculation of the filter can be reduced, and the overhead amount for notifying the wireless transmission apparatus of the index of the desired linear filter can be reduced.

  (4) In addition, the wireless transmission device of the present invention includes a plurality of transmission antennas, performs precoding on each of the data signals addressed to the plurality of wireless reception devices, and spatially multiplexes the signals after the precoding. A wireless transmission device for transmission, wherein a plurality of first linear filters used for the precoding store a first codebook in which each group is described, and each of the wireless reception devices A user selection unit that determines the group for each of the wireless reception devices based on the individual identification number, and selects a plurality of the wireless reception devices with different determined groups as targets for spatial multiplexing. And

  In this way, the wireless transmission device determines a group for each wireless reception device based on the individual identification number of the wireless reception device, and selects a plurality of wireless reception devices with different determined groups as targets for spatial multiplexing. There is no need to notify the codebook group from the wireless transmission device to the wireless reception device, and the amount of downlink notification information can be reduced.

  (5) In the wireless transmission device of the present invention, the first codebook includes a plurality of the first linear filters classified into a plurality of groups so as to have an orthogonal relationship between different groups. Is described.

  As described above, the first codebook describes the plurality of first linear filters that are classified into a plurality of groups so as to have orthogonal relations between different groups. , Multiplexing by MU-MIMO becomes possible with a sufficiently small IUI. Thereby, the space multiplexing opportunity by MU-MIMO increases, and frequency use efficiency can be improved.

  (6) Further, the radio reception apparatus of the present invention includes a plurality of transmission antennas, performs precoding on each of the data signals addressed to the plurality of radio reception apparatuses, and spatially multiplexes the signals after the precoding. A wireless reception device that receives a wireless signal transmitted from a transmitting wireless transmission device, wherein a plurality of first linear filters used for the precoding store a first codebook described for each of a plurality of groups A receiving side codebook storage unit, a control information acquisition unit for acquiring group information designating any one of the groups notified from the wireless transmission device, and a group storage for storing the acquired group information And the first linear filter belonging to the group indicated by the stored group information. A desired filter calculation unit that selects a filter, and a notification information generation unit that generates notification information for notifying the wireless transmission device of an index that is an identification number of the selected first linear filter. .

  In this way, the wireless reception device acquires group information specifying one of the groups notified from the wireless transmission device, stores the acquired group information, and belongs to the group indicated by the stored group information. Since one of the linear filters is selected, it is possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (7) In the wireless reception device of the present invention, the reception-side codebook storage unit stores a second codebook in which a plurality of second linear filters are described, and the desired filter calculation unit One of the second linear filters is selected.

  In this way, since the wireless reception device further selects one of the second linear filters, the two codebooks described in the two codebooks of the first codebook and the second codebook respectively. Precoding can be performed by a linear filter combined with a linear filter. This makes it possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter of the first codebook in the codebook-based closed-loop MU-MIMO, and the desired linearity in the wireless reception device. The amount of calculation required for the calculation of the filter can be reduced, and the overhead amount for notifying the wireless transmission apparatus of the index of the desired linear filter can be reduced.

  (8) In addition, the wireless reception device of the present invention includes a plurality of transmission antennas, performs precoding on each of data signals addressed to the plurality of wireless reception devices, and spatially multiplexes the signals after the precoding. A wireless reception device that receives a wireless signal transmitted from a transmitting wireless transmission device, wherein a plurality of first linear filters used for the precoding store a first codebook described for each of a plurality of groups A receiving side codebook storage unit, an identification number storage unit storing an individual identification number of the own device, and selecting one of the groups based on the stored individual identification number, and selecting A desired filter calculation unit that selects one of the first linear filters belonging to the selected group, and the selected first line A notification information generating unit that generates notification information for notifying the index is an identification number of the filter to the wireless transmitting device, characterized in that it comprises a.

  Thus, since the wireless reception device selects one of the groups based on the stored individual identification number and selects one of the first linear filters belonging to the selected group, wireless transmission is performed. There is no need to notify the codebook group from the apparatus to the radio reception apparatus, and the amount of downlink notification information can be reduced.

  (9) In addition, the wireless communication system of the present invention includes a plurality of wireless reception devices and a plurality of transmission antennas, and performs precoding on the data signals addressed to the plurality of wireless reception devices, respectively. A wireless communication system configured to spatially multiplex and transmit subsequent signals, wherein each wireless reception device includes a plurality of first linear filters used for the precoding in a plurality of groups In the first codebook described every time, one of the different first linear filters is selected from the different groups, and an index that is an identification number of the first linear filter is assigned to the wireless transmission device. The wireless transmission device notifies each first linearity represented by each index notified from each wireless reception device. Based on the filter, and performing the precoding.

  In this way, the plurality of wireless reception devices select one first linear filter from each of the different groups and notify the wireless transmission device of an index that is an identification number thereof, so that the wireless reception device can obtain the desired linearity. It is possible to reduce the number of candidates when calculating the filter. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (10) In the wireless communication system of the present invention, the wireless transmission device selects the different groups for the wireless reception devices, and notifies the wireless reception devices of the selected groups. And each said radio | wireless receiving apparatus selects any one 1st linear filter from the said group notified from the said radio | wireless transmitting apparatus, It is characterized by the above-mentioned.

  In this way, each wireless reception device selects one first linear filter from the group notified from the wireless transmission device, so that the number of candidates when the wireless reception device calculates a desired linear filter is reduced. Is possible. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (11) Moreover, in the radio | wireless communications system of this invention, each said radio | wireless receiving apparatus selects any one group among these groups based on the separate identification number allocated with respect to an own apparatus, One of the first linear filters is selected from the selected group.

  As described above, each wireless reception device selects one group from the group based on the individual identification number assigned to each wireless device, and selects one first linear filter from the selected group. There is no need to notify the codebook group from the apparatus to the radio reception apparatus, and the amount of downlink notification information can be reduced.

  (12) In the wireless communication system of the present invention, each wireless reception device selects any one second linear filter from a second codebook in which a plurality of second linear filters are described. Then, an index that is the identification number of the selected second linear filter is notified to the wireless transmission device, and the wireless transmission device is represented by each of the first and second indexes respectively notified from the wireless reception devices. The precoding is performed using a linear filter combined with a second linear filter.

  In this way, the plurality of wireless reception devices further select one second linear filter from the second codebook, respectively, and notify the wireless transmission device of the index that is the identification number. Precoding can be performed by a linear filter that is a combination of two linear filters respectively described in the two kinds of codebooks of the codebook and the second codebook. This makes it possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter of the first codebook in the codebook-based closed-loop MU-MIMO, and the desired linearity in the wireless reception device. The amount of calculation required for the calculation of the filter can be reduced, and the overhead amount for notifying the wireless transmission apparatus of the index of the desired linear filter can be reduced.

  (13) The control program of the present invention includes a plurality of transmission antennas, precodes data signals addressed to a plurality of radio reception apparatuses, and spatially multiplexes and transmits the precoded signals. And a process for storing a first codebook in which a plurality of first linear filters used for precoding are described for each of a plurality of groups and a target for spatial multiplexing A process of selecting a plurality of radio receiving apparatuses, selecting a different group for each selected radio receiving apparatus, and a process of generating control information for notifying each of the selected groups to the respective radio receiving apparatuses. A series of processing is executed by a computer.

  In this way, since the wireless transmission device selects a plurality of wireless reception devices to be subjected to spatial multiplexing and selects different groups for each, the number of candidates when the wireless reception device calculates a desired linear filter Can be reduced. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (14) The control program of the present invention includes a plurality of transmission antennas, precodes data signals addressed to a plurality of radio reception apparatuses, and spatially multiplexes and transmits the signals after the precoding. A first codebook which is a control program for a radio reception apparatus that receives a radio signal transmitted from a radio transmission apparatus that includes a plurality of first linear filters used for the precoding for each of a plurality of groups , A process for acquiring group information designating any one of the groups notified from the wireless transmission device, a process for storing the acquired group information, and the stored group A process of selecting any one of the first linear filters from the first linear filters belonging to the group indicated by the information. When the process of generating the notification information for notifying the index is an identification number of the first linear filter said selected to said wireless transmission apparatus, a series of processing, and characterized by causing a computer to execute.

  In this way, the wireless reception device acquires group information specifying one of the groups notified from the wireless transmission device, stores the acquired group information, and belongs to the group indicated by the stored group information. Since one of the linear filters is selected, it is possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (15) An integrated circuit according to the present invention is an integrated circuit that is mounted on a wireless transmission device having a plurality of transmission antennas to cause the wireless transmission device to perform a plurality of functions. A function of performing precoding on each data signal addressed to the apparatus, spatially multiplexing and transmitting the precoded signal, and a plurality of first linear filters used for the precoding are provided for each of a plurality of groups. A function for storing the described first codebook, a function for selecting a plurality of radio receiving apparatuses to be subjected to spatial multiplexing, a function for selecting the group different for each selected radio receiving apparatus, and each of the selected A function of generating control information for notifying each wireless reception device of a group, and a function of causing the wireless transmission device to exhibit a series of functions. To.

  In this way, since the wireless transmission device selects a plurality of wireless reception devices to be subjected to spatial multiplexing and selects different groups for each, the number of candidates when the wireless reception device calculates a desired linear filter Can be reduced. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  (16) Further, an integrated circuit according to the present invention is an integrated circuit that is mounted on a radio receiving device, thereby causing the radio receiving device to exhibit a plurality of functions, and includes a plurality of transmitting antennas and a plurality of radio receiving devices. A function of receiving a radio signal transmitted from a radio transmitting apparatus that performs pre-coding on each data signal addressed to the apparatus and spatially multiplexes and transmits the pre-coded signal; and a plurality of signals used for the pre-coding The first linear filter has a function of storing a first codebook described for each of a plurality of groups, and obtains group information specifying any one of the groups notified from the wireless transmission device A function to store the acquired group information, and the first linear filter belonging to the group indicated by the stored group information. A function for selecting one of the first linear filters from the data, a function for generating notification information for notifying the wireless transmission device of an index that is an identification number of the selected first linear filter, The wireless receiving device is caused to exhibit the series of functions.

  In this way, the wireless reception device acquires group information specifying one of the groups notified from the wireless transmission device, stores the acquired group information, and belongs to the group indicated by the stored group information. Since one of the linear filters is selected, it is possible to reduce the number of candidates when the wireless reception device calculates the desired linear filter. As a result, it is possible to reduce the amount of calculation necessary for calculating the desired linear filter in the wireless reception device, and further reduce the overhead amount for notifying the wireless transmission device of the index of the desired linear filter.

  According to the present invention, spatial code multiplexing opportunities of a mobile station apparatus can be improved in code book based closed loop MU-MIMO, and a desired linear filter is extracted from a linear filter group described in the code book in the mobile station apparatus. The amount of computation required to reduce the amount of overhead and the amount of overhead required for notification from the mobile station apparatus can be suppressed.

It is a functional block diagram which shows the example of 1 structure of the base station apparatus which concerns on the 1st Embodiment of this invention. It is a functional block diagram which shows the example of 1 structure of the mobile station apparatus which concerns on the 1st Embodiment of this invention. It is a sequence chart which shows the example of the process sequence between the base station apparatus which concerns on the 1st Embodiment of this invention, and multiple (U = 2) mobile station apparatuses. It is a functional block diagram which shows the example of 1 structure of the base station apparatus which concerns on the 2nd Embodiment of this invention. It is a sequence chart which shows the example of the process sequence between the base station apparatus which concerns on the 2nd Embodiment of this invention, and several (U = 2 pieces) mobile station apparatuses. It is a functional block diagram which shows the example of 1 structure of the base station apparatus which concerns on the 3rd Embodiment of this invention. It is a functional block diagram which shows the example of 1 structure of the mobile station apparatus which concerns on the 3rd Embodiment of this invention. It is a sequence chart which shows the example of the process sequence between the base station apparatus which concerns on the 3rd Embodiment of this invention, and several (U = 2 pieces) mobile station apparatuses. It is a sequence chart which shows the example of the process sequence between the base station apparatus which concerns on the 4th Embodiment of this invention, and several (U = 2 pieces) mobile station apparatuses.

In each embodiment according to the present invention, a plurality of mobile station devices (also referred to as reception devices and mobile terminals) having N _r reception antennas are used for a base station device (also referred to as a transmission device) having N _t transmission antennas. ) Is connected. Then, MU-MIMO transmission in which mobile station apparatuses with a maximum of U = 2 stations in the same radio resource are spatially multiplexed is targeted. However, since spatial multiplexing can be performed as many as N _t ≧ R × U (R is the number of ranks described later), the number of mobile station apparatuses spatially multiplexed on the same radio resource is limited to two. It is not a thing. In the following description, for the sake of simplicity, it is assumed that only one data stream is communicated to each mobile station apparatus. However, data streams corresponding to the number of reception antennas of each mobile station apparatus are transmitted simultaneously. It is also possible to do. Each mobile station apparatus may have a different number of reception antennas, and of course, the number of data streams transmitted to each mobile station apparatus may be different. Hereinafter, the number of data streams transmitted by the base station device per mobile station device is referred to as the rank number, and when R data streams are transmitted, transmission of rank R is performed. I will call it.

  Before describing specific embodiments, an outline of code processing based on a closed loop MU-MIMO based on codebook will be described. First, the base station apparatus transmits a known reference signal sequence to a plurality of connected mobile station apparatuses. Next, the mobile station apparatus performs propagation path estimation based on the received known reference signal sequence. Based on the estimated propagation path information, the mobile station apparatus extracts a linear filter most desirable for the own station from a known code book, and notifies the base station apparatus of the number (index) of the linear filter. The base station apparatus acquires a desired linear filter of each mobile station apparatus and performs transmission encoding (precoding) on transmission data addressed to each mobile station apparatus based on the information. Data after precoding is spatially multiplexed onto the same radio resource and transmitted to a plurality of connected mobile station apparatuses. A mobile station apparatus that has received a signal in which data addressed to a plurality of mobile station apparatuses is spatially multiplexed detects desired data of the local station based on the above-described propagation path information and the like.

In the mobile station apparatus, it is necessary to extract the most desirable linear filter from the code book for the own station. The code book is defined according to the number of transmission antennas of the base station apparatus and the number of transmission ranks to each mobile station apparatus. The codebook size, that is, the number of described linear filters is C, and the described linear filter is defined as {c _j ; j = 1,..., C}. Assuming that the channel matrix between the u-th mobile station apparatus and the base station apparatus is H _u and the linear filter desired by the u-th user is w _u , the linear filter that the u-th mobile station apparatus notifies the base station apparatus is It will satisfy the equation.

ここで、||ａ||はベクトルａのノルム演算を表す。また、ａｒｇｍａｘ_ｘ（ｆ（ｘ））は評価関数ｆ（ｘ）を最大とするｘを選択する関数であるから、式（１）の場合、||Ｈ_ｕ×ｃ_ｊ||^２を最大とするｃ_ｊをコードブック記載の線形フィルタ群から抽出し、それを基地局装置に通知する所望線形フィルタｗ_ｕとすることを意味している。なお、||Ｈ_ｕ×ｃ_ｊ||^２を最大とするということは、受信信号対雑音電力比（SNR）を最大とすることを意味している。なお、受信ＳＮＲの代わりに、受信信号対干渉および雑音電力比（SINR）や、通信容量を最大とするような線形フィルタを抽出するようにしても良い。

Here, || a || represents the norm operation of the vector a. Further, argmax _x (f (x)) Since a function that selects the x which maximizes the evaluation function f (x), the case of formula (1), and the maximum || _{H u} × _{c j} || ² This means that c _j to be extracted from the linear filter group described in the code book is used as a desired linear filter w _u to notify the base station apparatus. Note that maximizing || H _u × c _j || ² means maximizing the received signal-to-noise power ratio (SNR). Instead of the received SNR, a linear filter that maximizes the received signal-to-interference and noise power ratio (SINR) and the communication capacity may be extracted.

In each embodiment of the present invention, the linear filter group {c _j ; j = 1 to C} described in the codebook is classified into a plurality of groups (subsets) orthogonal to each other (hereinafter, this group is referred to as “group”). Called a codebook group). For the sake of simplicity, in the following embodiments, a case where N _t = 2, N _r = 1, and U = 2 will be described as an example. Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a functional block diagram showing a configuration example of a base station apparatus according to the first embodiment of the present invention. The codebook storage unit 101 classifies a plurality of linear filters used for precoding into a plurality of groups so as to have an orthogonal relationship between different groups, and stores them together with respective identification numbers (indexes). In addition to the identification number in the entire code book, it is preferable to provide an identification number in the group as the identification number of each linear filter. Group selection section 103 selects U (= 2) mobile station devices to be subjected to spatial multiplexing in MU-MIMO transmission from a plurality of mobile station devices connected to the base station device (first The mobile station apparatus and the second mobile station apparatus) select codebook groups that are orthogonal to each other with respect to the selected mobile station apparatus.

  Control information generating section 105 generates control information including code book group information for notifying each mobile station apparatus of the code book group for each mobile station apparatus selected by group selecting section 103, and first radio section 107-1. Or it transmits to each mobile station apparatus through the 2nd radio | wireless part 107-2 or both the radio | wireless transmission part 109 and the antenna part 111. The notification information acquisition unit 113 receives the notification information from each mobile station device through the antenna unit 111 and the radio reception unit 115 of the first radio unit 107-1 or the second radio unit 107-2, or both, and The index of the linear filter selected by the station apparatus is acquired.

Based on the linear filter index acquired by the notification information acquisition unit 113, the filter calculation unit 117 uses a desired linear filter w ₁ (first movement) of each mobile station device from the code book stored in the code book storage unit 101. Station device) and w ₂ (second mobile station device) are obtained, and the linear filter W _eff used for generating the MU-MIMO signal in the precoding unit is calculated. Specifically, it is obtained as follows. First, from {w ₁ , w ₂ }, an apparent channel matrix H _eff between each mobile station apparatus and the base station apparatus is defined as follows:

見掛け上の伝搬路行列Ｈ_ｅｆｆは各移動局装置から通知された線形フィルタ（ここではｗ_１とｗ_２）にエルミート転置を与えることで得られる行ベクトルを行方向に結合することにより得ることができる。ここでは、同時空間多重移動局装置数を２としているが、空間多重数が３以上となった場合も、同様に伝搬路行列Ｈ_ｅｆｆを定義できる。

The apparent channel matrix H _eff can be obtained by combining row vectors obtained by applying Hermite transposition to linear filters (here, w ₁ and w ₂ ) notified from each mobile station apparatus in the row direction. it can. Here, the number of simultaneous spatial multiplexing mobile station apparatuses is 2, but when the number of spatial multiplexing is 3 or more, the channel matrix H _eff can be similarly defined.

A linear filter W _eff used in the precoding unit is generated from the propagation path matrix H _eff given by Expression (2). The linear filter W _eff used in the present embodiment is a matrix that converts the propagation path matrix H _eff into a diagonal matrix, and such a matrix can be generated by _obtaining a general inverse matrix of H _eff .

ここでＡ^＋は行列Ａの一般逆行列を表す。式（３）で表される線形フィルタは移動局装置にて観測される雑音電力が無いと仮定した場合に、ＩＵＩが発生しないようにするＺｅｒｏ-ｆｏｒｃｉｎｇ（ZF）規範に基づいている。ＺＦ規範ではなく、受信信号と送信信号との平均二乗誤差を最小にするＭｉｎｉｍｕｍ ｍｅａｎ ｓｑｕａｒｅ ｅｒｒｏｒ（MMSE）規範や、ある移動局装置宛の送信信号が他移動局装置に与える与干渉電力（Leakage power）を最小とするＳｉｇｎａｌ-ｔｏ-ｌｅａｋａｇｅ ｐｏｗｅｒ ｒａｔｉｏ（SLR）規範や、所望信号電力と与干渉＋受信雑音電力の比を最大とするＳｉｇｎａｌ-ｔｏ-ｌｅａｋａｇｅ ｐｌｕｓ ｎｏｉｓｅ ｐｏｗｅｒ ｒａｔｉｏ（SLNR）規範に基づいて線形フィルタを生成しても良い。

Here, A ⁺ represents a general inverse matrix of the matrix A. The linear filter represented by Expression (3) is based on a zero-forcing (ZF) standard that prevents an IUI from occurring when there is no noise power observed in the mobile station apparatus. Instead of the ZF standard, the minimum mean square error (MMSE) standard that minimizes the mean square error between the received signal and the transmitted signal, or the interference power (Leakage power) that a transmission signal addressed to a certain mobile station apparatus gives to another mobile station apparatus ) Based on the signal-to-leakage power ratio (SLR) norm and the signal-to-leakage plus noise power ratio (SLNR) norm that maximizes the ratio of desired signal power to interference + received noise power. A linear filter may be generated.

First encoding section 119-1 and second encoding section 119-2 perform error correction encoding on the data series addressed to the first mobile station apparatus and the data series addressed to the second mobile station apparatus, respectively. Apply. First modulation unit 121-1 and the second modulation unit 121-2, for the data series d ₂ of the first data sequence d ₁ and the second mobile station addressed to the mobile station apparatus which is error correction coding Are respectively modulated to generate modulation symbol sequences s ₁ and s ₂ . First reference signal multiplexing section 123-1 and second reference signal multiplexing section 123-2 multiplex (insert) a known reference signal sequence into a modulation symbol sequence. Note that the reference signal sequence multiplexed by the first reference signal multiplexing unit 123-1 and the reference signal sequence multiplexed by the second reference signal multiplexing unit 123-2 need to be separated at the time of reception. Multiplexing is performed using orthogonal sequences or multiplexing methods (time division multiplexing, frequency division multiplexing, etc.). In addition, it is preferable that a reference signal sequence used for estimating a propagation path between the base station apparatus and the mobile station apparatus is not subjected to precoding processing in the subsequent precoding unit 125.

The precoding unit 125 multiplies the linear symbol W _eff calculated by the filter calculation unit 117 by the modulation symbol vector s = [s ₁ s ₂ ] ^T (the reference signal is multiplexed) to generate a MU-MIMO signal. The superscript T indicates transposition. The first radio unit 107-1 and the second radio unit 107-2 transmit the MU-MIMO signal generated by the precoding unit 125 through the radio transmission unit 109 and the antenna unit 111, respectively.

  FIG. 2 is a functional block diagram showing a configuration example of the mobile station apparatus according to the first embodiment of the present invention. Control information acquisition section 201 receives control information from the base station apparatus through antenna section 205 and radio reception section 207 of radio section 203, and acquires codebook group information. The group storage unit 209 stores the code book group information acquired by the control information acquisition unit 201. The reference signal separation unit 211 separates the reception signal received through the antenna unit 205 and the wireless reception unit 207 of the wireless unit 203 into a reception reference signal and a reception data signal. The propagation path estimation unit 213 estimates the state of the propagation path between each antenna of the base station apparatus and the antenna of the own mobile station apparatus based on the received reference signal separated / extracted by the reference signal separation unit 211.

  The desired filter calculation unit 215 refers to the code book stored in the code book storage unit 217, and from among the linear filters included in the code book group indicated by the code book group information stored in the group storage unit 209, A desired linear filter is calculated (selected) on the basis of the equation (1) using the propagation path estimation result, and its index is output. Since the number of selectable linear filter candidates is reduced by designating the code book group, the amount of calculation required for calculating the desired linear filter in the mobile station apparatus is reduced.

  The notification information generation unit 219 generates notification information output from the desired filter calculation unit 215 to notify the index of the desired linear filter to the base station apparatus, and the base station through the radio transmission unit 221 and the antenna unit 205 of the radio unit 203 Send to station device. Since the number of selectable linear filter candidates is reduced by designating the codebook group, the amount of notification information (number of bits) required to express the desired linear filter index is reduced. The overhead amount has been reduced. The propagation path compensation unit 223 performs propagation path compensation (propagation path equalization) on the received data signal separated and extracted by the reference signal separation unit 211 based on the propagation path estimation result. Further, the propagation path compensation unit 223 may calculate the reception filter based on the desired linear filter selected by the desired filter calculation unit 215 and the propagation path estimation result, and multiply the reception signal. Demodulation section 225 performs demodulation processing on the reception data signal that has been subjected to propagation path compensation, and outputs a reception encoded data sequence. Decoding section 227 performs error correction decoding on the received encoded data signal and outputs a received data sequence (estimated value of transmission data sequence).

  FIG. 3 is a sequence chart illustrating an example of a processing procedure between the base station apparatus and a plurality (U = 2) of mobile station apparatuses according to the first embodiment of the present invention. First, the base station apparatus selects the first mobile station apparatus and the second mobile station apparatus as the mobile station apparatuses to be subjected to spatial multiplexing in MU-MIMO transmission (step S101). Then, different codebook groups that are orthogonal to each other are selected and notified (step S102). Next, the base station apparatus transmits a known reference signal (step S103). Each mobile station apparatus estimates the state of a propagation path with the base station apparatus based on the reception result of the reference signal (step S104). Each mobile station apparatus selects the most desirable linear filter for itself from the linear filters belonging to the notified codebook group based on the respective propagation path estimation results (step S105), and the index is assigned to the base station apparatus. (Step S106).

  In the base station apparatus, based on the linear filter indicated by the index notified from each mobile station apparatus, precoding is performed on the data series addressed to each mobile station apparatus to generate a spatially multiplexed MU-MIMO signal. (Step S107) and transmit (step S108). Each mobile station apparatus receives the MU-MIMO signal and detects data addressed to the mobile station apparatus based on the above-described propagation path information and the like (step S109).

  According to the present embodiment, by reducing the number of candidates when the mobile station apparatus calculates the desired linear filter, it is possible to reduce the amount of calculation required for calculating the desired linear filter in the mobile station apparatus, and further, The overhead amount for notifying the base station apparatus of the index can also be reduced. Furthermore, since the desired linear filters selected and notified by each mobile station apparatus are selected from codebook groups that are orthogonal to each other, multiplexing by MU-MIMO is possible with a sufficiently small IUI. Spatial multiplexing opportunities by MU-MIMO are increased, and frequency use efficiency can be improved.

(Second Embodiment)
FIG. 4 is a functional block diagram showing a configuration example of a base station apparatus according to the second embodiment of the present invention. The arrival direction estimation unit 301 includes the first radio unit 107-1, the second radio unit 107-2, or both of the antenna unit 111 and the radio reception unit for a plurality of mobile station devices connected to the base station device. The uplink signal from each mobile station apparatus is received through 115, and the arrival direction of the signal from each mobile station apparatus is estimated from the correlation of the received signal of each antenna unit 111 and the like. Group selection section 103 selects U (= 2) mobile station apparatuses to be subjected to spatial multiplexing in MU-MIMO transmission based on the arrival direction estimation result by arrival direction estimation section 301 (first mobile station Device and a second mobile station device), and a codebook group that is orthogonal to the selected mobile station device. The other configuration is the same as that of the base station apparatus of FIG. Further, the configuration of the mobile station apparatus in the present embodiment is the same as that of the mobile station apparatus of FIG.

  FIG. 5 is a sequence chart showing an example of a processing procedure between the base station apparatus and a plurality (U = 2) of mobile station apparatuses according to the second embodiment of the present invention. First, the base station apparatus receives an uplink signal from each connected mobile station apparatus (step S201), and estimates the arrival direction of each uplink signal (step S202). The base station apparatus determines the first mobile station apparatus and the second mobile station apparatus as a set of mobile station apparatuses to be subjected to spatial multiplexing in MU-MIMO transmission based on the estimation result of the signal arrival direction from each mobile station apparatus. Are selected, different codebook groups orthogonal to each other are selected (step S203), and each is notified (step S204). In addition, it is preferable to select a mobile station apparatus to be subjected to spatial multiplexing in MU-MIMO transmission in combination with mobile station apparatuses in which the angle formed by each signal arrival direction is as large as possible.

  Next, the base station apparatus transmits a known reference signal (step S205). Each mobile station apparatus estimates the state of a propagation path with the base station apparatus based on the reception result of the reference signal (step S206). Each mobile station apparatus selects the most desirable linear filter for itself from the linear filters belonging to the notified codebook group based on the respective propagation path estimation results (step S207), and the index is assigned to the base station apparatus. (Step S208). In the base station apparatus, based on the linear filter indicated by the index notified from each mobile station apparatus, precoding is performed on the data series addressed to each mobile station apparatus to generate a spatially multiplexed MU-MIMO signal. (Step S209) and transmit (step S210). Each mobile station apparatus receives the MU-MIMO signal and detects data addressed to the mobile station apparatus based on the above-described propagation path information and the like (step S211).

  According to this embodiment, first, the base station apparatus selects a mobile station apparatus that is a target of spatial multiplexing in MU-MIMO transmission based on the direction of arrival from the mobile station apparatus, so that the orthogonality is higher and higher. It becomes possible to select a set of mobile station apparatuses that can obtain MU-MIMO transmission efficiency. In addition, by reducing the number of candidates when the mobile station apparatus calculates the desired linear filter, the amount of computation required for calculating the desired linear filter in the mobile station apparatus can be reduced, and the index of the desired linear filter can be assigned to the base station apparatus. It is also possible to reduce the overhead amount for notifying the user. Furthermore, since the desired linear filters selected and notified by each mobile station apparatus are selected from codebook groups that are orthogonal to each other, multiplexing by MU-MIMO is possible with a sufficiently small IUI. Spatial multiplexing opportunities by MU-MIMO are increased, and frequency use efficiency can be improved.

(Third embodiment)
In the communication system according to the present embodiment, a codebook group is determined in advance by an individual identification number such as a user ID for identifying a mobile station device.
FIG. 6 is a functional block diagram showing a configuration example of a base station apparatus according to the third embodiment of the present invention. Identification number generation section 401 generates an individual identification number to be assigned to each mobile station apparatus connected to its own base station apparatus, and first radio section 107-1 or second radio section 107-2, or both radio transmission sections 109 and the antenna unit 111 to transmit to each mobile station apparatus. Based on the individual identification numbers assigned to each mobile station apparatus, the user selection unit 403 uses U (= 2) mobile station apparatuses whose codebook groups based on these individual identification numbers are orthogonal to each other, MU-MIMO It selects as the object of the spatial multiplexing in transmission (a 1st mobile station apparatus and a 2nd mobile station apparatus). The notification information acquisition unit 113 receives notification information from each mobile station device through the antenna unit 111 and the radio reception unit 115 of the first radio unit 107-1 and / or the second radio unit 107-2, and is selected by the user. The index of the linear filter selected by the U mobile station apparatuses selected by the unit 403 is acquired. The other configuration is the same as that of the base station apparatus of FIG.

  FIG. 7 is a functional block diagram showing a configuration example of a mobile station apparatus according to the third embodiment of the present invention. The identification number acquisition unit 501 receives the notification of the individual identification number from the base station device through the antenna unit 205 and the wireless reception unit 207 of the wireless unit 203, and acquires codebook group information. The identification number storage unit 503 stores the individual identification number acquired by the identification number acquisition unit 501. The desired filter calculation unit 215 refers to the code book stored in the code book storage unit 217, obtains a code book group determined in advance for the individual identification number stored in the identification number storage unit 503, and From the linear filters included in the codebook group, a desired linear filter is calculated (selected) on the basis of the equation (1) using the propagation path estimation result, and the index is output. Since the number of selectable linear filter candidates is reduced by designating the code book group, the amount of calculation required for calculating the desired linear filter in the mobile station apparatus is reduced. Other configurations are the same as those of the mobile station apparatus of FIG.

  FIG. 8 is a sequence chart showing an example of a processing procedure between a base station apparatus and a plurality (U = 2) of mobile station apparatuses according to the third embodiment of the present invention. First, the base station apparatus notifies each mobile station apparatus of an individual identification number (step S301). The individual identification number is preferably assigned and notified by the base station device when each mobile station device starts connection to the base station device, but is not limited thereto. Also, the individual identification number is not assigned and notified by the base station apparatus. For example, the mobile station apparatus assigns the individual identification information by a predetermined method based on cell information (cell identification number) formed by the base station apparatus. It may be generated. The base station apparatus is a mobile station apparatus to be subjected to spatial multiplexing in MU-MIMO transmission, and includes a first mobile station apparatus and a second mobile station apparatus in which codebook groups based on individual identification numbers are orthogonal to each other. Two are selected (step S302).

  Next, the base station apparatus transmits a known reference signal (step S303). Each mobile station apparatus estimates the state of the propagation path with the base station apparatus based on the reception result of the reference signal (step S304). Each mobile station apparatus selects the most desirable linear filter for the own station from the linear filters belonging to the codebook group based on the individual identification number of the own mobile station apparatus based on the respective propagation path estimation results (step S305). The index is notified to the base station apparatus (step S306). In the base station apparatus, based on the linear filter indicated by the index notified from each mobile station apparatus, precoding is performed on the data series addressed to each mobile station apparatus to generate a spatially multiplexed MU-MIMO signal. (Step S307) and transmit (step S308).

  Each mobile station apparatus receives the MU-MIMO signal and detects data addressed to the mobile station apparatus based on the above-described propagation path information and the like (step S309).

  According to the present embodiment, by reducing the number of candidates when the mobile station apparatus calculates the desired linear filter, it is possible to reduce the amount of calculation required for calculating the desired linear filter in the mobile station apparatus, and further, The overhead amount for notifying the base station apparatus of the index can also be reduced. Also, since the codebook group is determined based on the individual identification number of each mobile station apparatus, it is not necessary to notify the codebook group from the base station apparatus to the mobile station apparatus, and the amount of downlink notification information can be reduced. . Furthermore, since the desired linear filters selected and notified by each mobile station apparatus are selected from codebook groups that are orthogonal to each other, multiplexing by MU-MIMO is possible with a sufficiently small IUI. Spatial multiplexing opportunities by MU-MIMO are increased, and frequency use efficiency can be improved.

(Fourth embodiment)
In the present embodiment, a codebook that performs precoding using a linear filter that is a combination of _two linear filters (W ₁ , W ₂ ) respectively described in two types of codebooks, the first codebook and the second codebook. The present invention is applied to a base closed-loop MU-MIMO.

  FIG. 9 is a sequence chart showing an example of a processing procedure between a base station apparatus and a plurality (U = 2) of mobile station apparatuses according to the fourth embodiment of the present invention. First, the base station apparatus selects the first mobile station apparatus and the second mobile station apparatus as the mobile station apparatuses to be subjected to spatial multiplexing in MU-MIMO transmission, and is orthogonal to each other. Are selected (step S401), and each is notified (step S402). Next, the base station apparatus transmits a known reference signal (step S403). Each mobile station apparatus estimates the state of the propagation path with the base station apparatus based on the reception result of the reference signal (step S404).

Each mobile station apparatus, based on each propagation path estimation result, out of the linear filters belonging to the code book group of the notified first code book, the most desirable linear filter (first linear filter W ₁ ) Is selected (step S405), and the index is notified to the base station apparatus (step S406). Further, each mobile station apparatus uses the second code to select the second linear filter W ₂ that is most desirable for the local station when combined with the first linear filter selected above based on the respective propagation path estimation results. A linear filter belonging to the book is selected (step S407), and the index is notified to the base station apparatus (step S408). In the base station apparatus, each mobile station apparatus obtains a matrix product W ₁ W ₂ of two linear filters indicated by the index of the first linear filter W _{1 and} the index of the second linear filter W ₂ notified from each mobile station apparatus. As the desired linear filters w ₁ (first mobile station apparatus) and w ₂ (second mobile station apparatus), using the linear filters obtained from the equations (2) and (3), the respective mobile stations Precoding is performed on the data sequence addressed to the apparatus to generate a spatially multiplexed MU-MIMO signal (step S409) and transmit (step S410). Each mobile station apparatus receives the MU-MIMO signal and detects data addressed to the mobile station apparatus based on the above-described propagation path information and the like (step S411).

The configuration of the base station apparatus in the present embodiment is the same as that of the base station apparatus of FIG. 1, and the codebook storage unit further stores the linear filter included in the second codebook and its identification number, and notification information acquisition The first linear filter W ₁ index and the second linear filter W ₂ index are acquired in the unit, and the matrix product W ₁ of the first linear filter W ₁ and the second linear filter W ₂ is acquired in the filter calculation unit. The difference is that a linear filter is calculated using W ₂ as a desired linear filter w ₁ (first mobile station apparatus) and w ₂ (second mobile station apparatus) of each mobile station apparatus.

Further, the configuration of the mobile station apparatus in the present embodiment is the same as that of the mobile station apparatus of FIG. 2, the point that the control information acquisition unit acquires code book group information related to the first code book, and the group storage unit The code book group information related to the first code book acquired by the control information acquisition unit and the code book group information related to the first code book stored in the group storage unit by the desired filter calculation unit are indicated. When a linear filter (first linear filter W ₁ ) most desirable for the own station is selected from among the linear filters belonging to the code book group relating to the first code book, the own station is combined with the selected first linear filter. the most preferred second to a linear filter W _2, selected from linear filter belonging to the second codebook, their Point to output the index is different.

According to the present embodiment, precoding is performed using a linear filter that is a combination of _two linear filters (W ₁ , W ₂ ) respectively described in two types of codebooks, the first codebook and the second codebook. In codebook-based closed-loop MU-MIMO, the number of candidates when the mobile station apparatus calculates the desired linear filter of the first codebook is reduced, thereby calculating necessary linear filter in the mobile station apparatus. In addition, the amount of overhead for notifying the base station apparatus of the index of the desired linear filter can be reduced. Furthermore, since the desired linear filters selected and notified by each mobile station apparatus are selected from codebook groups that are orthogonal to each other, multiplexing by MU-MIMO is possible with a sufficiently small IUI. Spatial multiplexing opportunities by MU-MIMO are increased, and frequency use efficiency can be improved.

  In each of the embodiments described above, there is no restriction on the transmission method (or access method). For example, the present invention can be applied to an Orthogonal Frequency Division Multiple Access (OFDMA) system that is employed in LTE downlink transmission. In this case, the present invention may be applied to each subcarrier, and the present invention may be applied to each resource block in which a plurality of subcarriers are grouped. Similarly, it can be applied to single carrier-based access methods (for example, Single Carrier-Frequency Division Multiple Access (SC-FDMA) method). In order to avoid emphasizing transmission power, the same precoding may be performed over the entire frequency band.

  The program that operates in the communication apparatus according to the present invention may be a program that controls a CPU (Central Processing Unit) or the like (a program that causes a computer to function) so as to realize the functions of the above-described embodiments related to the present invention. Information handled by these devices is temporarily stored in RAM (Random Access Memory) during the processing, and then stored in various ROMs such as Flash ROM (Read Only Memory) and HDD (Hard Disk Drive). Reading, correction, and writing are performed by the CPU as necessary.

  Also, by recording a program for realizing the functions of the components shown in FIGS. 1 and 2 on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. You may perform the process of each part. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included.

  The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. Further, part or all of the communication devices (base station device and terminal device) in the above-described embodiment may be realized as an LSI that is typically an integrated circuit. Each functional block of the communication device may be individually chipped, or part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the invention may be changed in design without departing from the gist of the present invention. Is also included. The present invention is applicable to a wireless communication system and a wireless communication device such as a mobile phone and a wireless LAN.

101 codebook storage unit 103 group selection unit 105 control information generation unit 107-1 first radio unit 107-2 second radio unit 109 radio transmission unit 111 antenna unit 113 notification information acquisition unit 115 radio reception unit 117 filter calculation unit 119- DESCRIPTION OF SYMBOLS 1 1st encoding part 119-2 2nd encoding part 121-1 1st modulation part 121-2 2nd modulation part 123-1 1st reference signal multiplexing part 123-2 2nd reference signal multiplexing part 125 Precoding part 201 control information acquisition unit 203 radio unit 205 antenna unit 207 radio reception unit 209 group storage unit 211 reference signal separation unit 213 propagation path estimation unit 215 desired filter calculation unit 217 codebook storage unit 219 notification information generation unit 221 radio transmission unit 223 propagation Path compensation unit 225 Demodulation unit 227 Decoding unit 301 Arrival direction estimation unit 401 Identification number generation unit 403 The selection unit 501 identification number obtaining unit 503 identification number storage unit

Claims (16)

A wireless transmission device that includes a plurality of transmission antennas, performs precoding on data signals addressed to a plurality of wireless reception devices, and spatially multiplexes and transmits the signals after the precoding,
A codebook storage unit that stores a first codebook in which a plurality of first linear filters used for the precoding are described for each of a plurality of groups;
A plurality of radio reception devices to be spatially multiplexed, a group selection unit that selects different groups for each selected radio reception device;
A radio transmission apparatus comprising: a control information generation unit that generates control information for notifying each radio reception apparatus of each selected group. An arrival direction estimation unit that estimates an arrival direction of a radio signal transmitted from the radio reception device;
The said group selection part selects the some radio | wireless receiving apparatus made into the object of spatial multiplexing based on the arrival direction estimation result of the radio signal transmitted from each said radio | wireless receiving apparatus. Wireless transmission device. The code book storage unit stores a second code book in which a plurality of second linear filters are described,
The radio transmitting apparatus according to claim 1, wherein the precoding is performed using a linear filter that is a combination of the first and second linear filters. A wireless transmission device that includes a plurality of transmission antennas, performs precoding on data signals addressed to a plurality of wireless reception devices, and spatially multiplexes and transmits the signals after the precoding,
A codebook storage unit that stores a first codebook in which a plurality of first linear filters used for the precoding are described for each of a plurality of groups;
A user selection unit that determines the group for each wireless reception device based on the individual identification number of each wireless reception device, and selects a plurality of the wireless reception devices with different determined groups as targets of spatial multiplexing; A wireless transmission device comprising:   The first codebook describes a plurality of the first linear filters classified into a plurality of groups so as to have orthogonal relations between different groups. The wireless transmission device according to claim 4. A plurality of transmission antennas are provided, each of the data signals addressed to a plurality of radio reception apparatuses is precoded, and the radio signal transmitted from the radio transmission apparatus that spatially multiplexes and transmits the precoded signal is received. A wireless receiving device,
A receiving-side codebook storage unit that stores a first codebook in which a plurality of first linear filters used for the precoding are described for each of a plurality of groups;
A control information acquisition unit for acquiring group information specifying any one of the groups notified from the wireless transmission device;
A group storage unit for storing the acquired group information;
A desired filter calculation unit that selects any one first linear filter from the first linear filters belonging to the group indicated by the stored group information;
A radio reception apparatus comprising: a notification information generation unit that generates notification information for notifying the radio transmission apparatus of an index that is an identification number of the selected first linear filter. The receiving-side codebook storage unit stores a second codebook in which a plurality of second linear filters are described,
The radio reception apparatus according to claim 6, wherein the desired filter calculation unit selects any one of the second linear filters. A plurality of transmission antennas are provided, each of the data signals addressed to a plurality of radio reception apparatuses is precoded, and the radio signal transmitted from the radio transmission apparatus that spatially multiplexes and transmits the precoded signal is received. A wireless receiving device,
A receiving-side codebook storage unit that stores a first codebook in which a plurality of first linear filters used for the precoding are described for each of a plurality of groups;
An identification number storage unit for storing the individual identification number of the own device;
Based on the stored individual identification number, any one of the groups is selected, and any one of the first linear filters belonging to the selected group is selected. A desired filter calculation unit;
A radio reception apparatus comprising: a notification information generation unit that generates notification information for notifying the radio transmission apparatus of an index that is an identification number of the selected first linear filter. A plurality of wireless receivers;
A wireless transmission device comprising a plurality of transmission antennas, a wireless transmission device configured to pre-code data signals addressed to the plurality of wireless reception devices, respectively, and to spatially multiplex and transmit the pre-coded signals A communication system,
Each of the radio reception devices includes a first codebook in which a plurality of first linear filters used for the precoding are described for each of a plurality of groups. Selecting a linear filter and notifying the wireless transmitter of an index that is the identification number of the first linear filter;
The wireless communication system, wherein the wireless transmission device performs the precoding based on the first linear filters represented by the indexes respectively notified from the wireless reception devices. The radio transmission device selects the different groups for the radio reception devices, and notifies the radio reception devices of the selected groups,
The wireless communication system according to claim 9, wherein each of the wireless reception devices selects any one of the first linear filters from the group notified from the wireless transmission device.   Each of the wireless reception devices selects any one of the plurality of groups based on an individual identification number assigned to the own device, and selects any one of the first groups from the selected group. The wireless communication system according to claim 9, wherein a linear filter is selected. Each of the wireless reception devices selects any one second linear filter from a second codebook describing a plurality of second linear filters, and the identification number of the selected second linear filter Is notified to the wireless transmission device,
The radio transmitting apparatus performs the precoding using a linear filter that is a combination of the first and second linear filters represented by indexes notified from the radio receiving apparatuses. 9. The wireless communication system according to 9. A control program for a wireless transmission device comprising a plurality of transmission antennas, precoding data signals addressed to a plurality of wireless reception devices, and spatially multiplexing and transmitting the precoded signals,
A process of storing a first codebook in which a plurality of first linear filters used for the precoding are described for a plurality of groups;
A process of selecting a plurality of radio receiving devices to be subjected to spatial multiplexing and selecting the different groups for each selected radio receiving device;
A control program for causing a computer to execute a series of processes including a process of generating control information for notifying each of the selected groups to each of the wireless reception devices. A plurality of transmission antennas are provided, each of the data signals addressed to a plurality of radio reception apparatuses is precoded, and the radio signal transmitted from the radio transmission apparatus that spatially multiplexes and transmits the precoded signal is received. A wireless receiver control program,
A process of storing a first codebook in which a plurality of first linear filters used for the precoding are described for a plurality of groups;
A process of acquiring group information specifying any one of the groups notified from the wireless transmission device;
Processing for storing the acquired group information;
A process of selecting any one first linear filter from among the first linear filters belonging to the group indicated by the stored group information;
A control program that causes a computer to execute a series of processes of generating notification information for notifying the wireless transmission device of an index that is an identification number of the selected first linear filter. An integrated circuit that allows a plurality of functions to be exhibited by the wireless transmission device when mounted on a wireless transmission device including a plurality of transmission antennas,
A function of performing precoding on each of data signals addressed to a plurality of radio receiving apparatuses, and spatially multiplexing and transmitting the signal after the precoding,
A plurality of first linear filters used for the precoding store a first codebook described in a plurality of groups;
A function of selecting a plurality of wireless reception devices to be subjected to spatial multiplexing and selecting the group different for each selected wireless reception device;
A function of generating control information for notifying each of the selected groups to each of the wireless reception devices, and causing the wireless transmission device to exhibit a series of functions. An integrated circuit that, when mounted on a wireless receiver, causes the wireless receiver to perform a plurality of functions,
A plurality of transmission antennas are provided, each of the data signals addressed to a plurality of radio reception apparatuses is precoded, and the radio signal transmitted from the radio transmission apparatus that spatially multiplexes and transmits the precoded signal is received. Function to
A plurality of first linear filters used for the precoding store a first codebook described in a plurality of groups;
A function of acquiring group information specifying any one of the groups notified from the wireless transmission device;
A function of storing the acquired group information;
A function of selecting any one first linear filter from among the first linear filters belonging to the group indicated by the stored group information;
A function of generating notification information for notifying the wireless transmission device of an index, which is an identification number of the selected first linear filter, and causing the wireless reception device to exhibit a series of functions. .

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