JP2004248206A - Radio station device, mobile terminal device, transmission power control method, and transmission power control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio station device, a mobile terminal device, a transmission power control method and a transmission power control program for making received power uniform for each path of a station when an MIMO terminal and a PDMA station are joined in spacial multiplex connection. <P>SOLUTION: Received power value for each path is measured at a station when a MIMO terminal having a plurality of antennae 21a, 21b and a PDMA station having array antennae 1, 2 are joined in spacial multiplex connection. In a station control unit 11, a control message for making upward transmission power for each path from a terminal uniform with each other under control and transmitted to the terminal. Terminal control units 27, 41 controls the upward transmission power for each path based on the control message. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

Ａは振幅であり、常にプラスの値になり、かつ同相であるため（複素平面上でベクトルの向きが同じであるということ）、所望局方向への信号は最大限強め合うことになる、すなわち、ビームの強度が最大化される。ただしこの場合、干渉局方向へも信号が放射される。これを実現する送信ウェイトを第２の送信ウェイトと称する。
【０２１９】
上述の第１の送信ウェイトと、この第２の送信ウェイトとの、適当な内挿補間値を送信ウェイトとすることで、所望基地局方向への送信電力を適宜制御することができる。
【０２２０】
このように、ＰＤＭＡ基地局から送信電力制御メッセージを受信したＭＩＭＯ端末では、メッセージをデコードし、その内容に基づいて、サブアレイアンテナごとの、すなわちパスごとの上り送信電力を制御することができ、この結果、基地局側での各パスの受信電力値を互いに均一なものにすることができる。
【０２２１】
今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
【０２２２】
【発明の効果】
以上のように、この発明によれば、複数アンテナを有する端末と空間多重接続可能な基地局とが複数のパスを介して多重通信している場合に、基地局でのそれぞれのパスの上り受信電力が均一なものとなるように、端末からの上り送信電力を基地局からの制御メッセージによって制御している。これにより、基地局でのパスごとの受信電力を互いに揃えることが可能となり、安定した空間多重通信を実現することができる。
【図面の簡単な説明】
【図１】この発明の実施の形態によるＰＤＭＡ基地局の構成を示す機能ブロック図である。
【図２】この発明の実施の形態による送信電力制御メッセージの内容を示す模式図である。
【図３】この発明の実施の形態１による送信電力制御方法を示すフロー図である。
【図４】この発明の実施の形態２による送信電力制御方法を示すフロー図である。
【図５】この発明の実施の形態３による送信電力制御方法を示すフロー図である。
【図６】この発明の実施の形態４による送信電力制御方法を示すフロー図である。
【図７】この発明の実施の形態５による送信電力制御方法を示すフロー図である。
【図８】この発明の実施の形態によるＭＩＭＯ端末の構成を示す機能ブロック図である。
【図９】この発明の実施の形態６による送信電力制御方法を示すフロー図である。
【図１０】この発明の実施の形態によるＭＩＭＯ端末の他の構成を示す機能ブロック図である。
【図１１】この発明の実施の形態７による送信電力制御方法を示すフロー図である。
【図１２】この発明の実施の形態８による送信電力制御方法を示すフロー図である。
【図１３】この発明の実施の形態９による送信電力制御方法を示すフロー図である。
【図１４】従来の１ユーザ１パス方式の接続態様を模式的に示す概念図である。
【図１５】ＭＩＭＯ方式による１ユーザ４パス方式の接続態様を模式的に示す概念図である。
【符号の説明】
１，２，２１ａ，２１ｂ，３１ａ，３２ａ，３１ｂ，３２ｂ アンテナ、３，４，２２ａ，２２ｂ，３３ａ，３４ａ，３３ｂ，３４ｂ スイッチ、５，６，８，９，２４ａ，２５ａ，２４ｂ，２５ｂ，３５ａ，３６ａ，３５ｂ，３６ｂ，３８ａ，３９ａ，３８ｂ，３９ｂ 乗算器、７，２３ａ，２３ｂ，３７ａ，３７ｂ発振器、１０ パス多重受信処理部、１１，２７，４１ 制御部、１２ パス多重送信処理部、２６ａ パス１送受信処理部、２６ｂ パス２送受信処理部、４０ａ パス１アレイ受信処理部、４０ｂ パス２アレイ受信処理部、４２ａ パス１アレイ送信処理部、４２ｂ パス２アレイ送信処理部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a radio base station, a mobile terminal, a transmission power control method, and a transmission power control program, and more particularly to a radio base station and a mobile terminal capable of forming a plurality of spatial paths by spatial multiplexing and performing multiplex communication. And a control method and control program for uplink transmission power via such a spatial path.
[0002]
[Prior art]
2. Description of the Related Art In recent years, mobile communication systems (for example, Personal Handyphone System: hereinafter, PHS), which are rapidly developing, are formed by spatially dividing the same time slot of the same frequency in order to increase the frequency use efficiency of radio waves. A space division multiple access scheme (PDMA) that allows a plurality of users' mobile radio terminals (terminals) to be spatially multiplex-connected to a radio base station (base station) via a plurality of spatial paths (hereinafter, simply referred to as paths). : Path Division Multiple Access or SDMA: Space Division Multiple Access has been proposed (for example, see Non-Patent Documents 1 and 2).
[0003]
In the PDMA system, an adaptive array technology is currently employed. Adaptive array processing is to extract a signal from a desired terminal accurately by calculating a weight vector composed of a reception coefficient (weight) for each antenna of a base station based on a signal received from the terminal and adaptively controlling the weight vector. This is the processing to be performed.
[0004]
By such adaptive array processing, the uplink signal from the antenna of each user terminal is received by the array antenna of the base station and separated and extracted with the reception directivity, and the downlink signal from the base station to the terminal is Are transmitted from the array antenna with the transmission directivity to the antenna of the terminal.
[0005]
Such adaptive array processing is a well-known technique and is described in detail in, for example, Non-Patent Document 1, so that the description of the operation principle will be omitted here.
[0006]
FIG. 14A shows a case where one terminal 2 with one antenna is connected to a PDMA base station via one of a plurality of paths formed by space division in such a PDMA mobile communication system (PHS). FIG. 2 is a conceptual diagram schematically showing a state of connection to the device 1;
[0007]
More specifically, the PDMA base station 1 receives the uplink signal from one antenna 2a of the terminal 2 by the array antenna 1a, separates and extracts the signal with the reception directivity by the above-described adaptive array processing. I have. On the other hand, from the array antenna 1a of the PDMA base station 1, a downlink signal is transmitted with the transmission directivity being directed to one antenna 2a of the terminal 2, and the terminal 2 side receives the antenna without performing adaptive array processing. The downlink signal is received at 2a.
[0008]
FIG. 14B is a timing chart schematically showing the manner of channel allocation in this case. In the case of FIG. 14B, users 1 to 4 are time-division multiplexed in the respective time slots divided in the time axis direction at the same frequency, and in each slot, one user passes through one path in the spatial direction. Users are assigned.
[0009]
On the other hand, a MIMO (Multi Input Multi Output) system has been proposed in which multiplex communication is performed between one terminal having a plurality of antennas and a PDMA base station via a plurality of spatial paths having the same frequency and the same time slot. (See, for example, Non-Patent Documents 3 and 4).
[0010]
FIG. 15A shows that, in such a mobile communication system (PHS) of the MIMO scheme, one terminal 12 having four antennas is connected to a PDMA through a plurality of (for example, four) paths formed by space division. FIG. 2 is a conceptual diagram schematically illustrating a state where the base station 11 is spatially multiplexed.
[0011]
More specifically, PDMA base station 11 receives uplink signals from each of four antennas 12a, 12b, 12c, and 12d of terminal 12 with array antenna 11a, and reduces the reception directivity by the adaptive array processing described above. Accompanying separation and extraction. On the other hand, from the array antenna 11a of the PDMA base station 11, a downlink signal is transmitted with the transmission directivity being directed to each of the four antennas 12a, 12b, 12c, and 12d of the terminal 12, and the terminal 12 has an adaptive array. The corresponding downlink signal is received by each antenna without performing the processing.
[0012]
FIG. 15B is a timing chart schematically showing the channel allocation in this case. In the case of FIG. 15 (b), users 1 to 4 are time-division multiplexed in the respective time slots divided in the time axis direction at the same frequency, and in each slot, the same in the spatial direction via four paths. Users are multiplexed and assigned.
[0013]
For example, paying attention to the first time slot in FIG. 15B, user 1 is allocated to all channels via four spatial paths. Then, the signal of the user 1 is divided and transmitted between the terminal and the base station via the four paths in the same slot, and these signals are reconstructed on the receiving side. With the one-user four-pass scheme as shown in FIG. 15B, the communication speed can be quadrupled as compared with the one-user one-pass scheme in FIG. 14B.
[0014]
A specific method of transmitting and receiving a MIMO signal as shown in FIG. 15 is disclosed in detail in Patent Document 1, for example.
[0015]
[Patent Document 1]
JP-A-11-3030
[0016]
[Non-patent document 1]
Toshinori Iinuma et al., "Adaptive Array Antenna PHS Base Station", "SANYO TECHNICAL REVIEW" (Sanyo Electric Technical Report), Sanyo Electric Co., Ltd., May 1, 2000, Vol. 32, No. 1, p. . 80-88
[0017]
[Non-patent document 2]
Yoshiharu Doi et al., "Space Division Multiple Access PHS Base Station", "SANYO TECHNICAL REVIEW" (Sanyo Electric Technical Report), Sanyo Electric Co., Ltd., issued December 10, 2001, Vol. 33, No. 3, p. . 93-101
[0018]
[Non-Patent Document 3]
Nishimura et al., "SDMA Downlink Beamforming Method on MIMO Channel", "IEICE Technical Report", IEICE, October 2001, A-P 2001-116, RCS 2001-155, p. 23-30
[0019]
[Non-patent document 4]
Tomisato et al., "Wireless signal processing in MIMO channel signal transmission for mobile communication", "IEICE Technical Report", IEICE, October 2001, A-P 2001-97, RCS 2001-136, p. 43-48
[0020]
[Problems to be solved by the invention]
In such a MIMO mobile communication system, a PDMA base station that allows spatial multiplexing access with a terminal having a plurality of antennas (hereinafter, MIMO terminal) requires a plurality of MIMO terminals from multiple antennas. Desired user's power: Desired user's power (hereinafter referred to as DD ratio) is desirably equal to each other.
[0021]
This is because if there is a large difference between the reception powers of a plurality of paths from the MIMO terminal, the interference cancellation capability of the adaptive array processing is not sufficient, and the reception signal of the lower reception power is regarded as a reception error. This is because there is a possibility. Therefore, in such a case, stable spatial multiplex communication cannot be maintained.
[0022]
However, in a MIMO terminal described later, the uplink transmission power value of each antenna is a predetermined fixed value, and the MIMO terminal does not perform uplink transmission power control. Accordingly, a signal of each path transmitted at a fixed transmission power value from a plurality of antennas of the MIMO terminal has a power difference due to a change in the propagation path environment for each path, and finally, a PDMA signal having a different reception power value from each other is generated. It will be received at the base station.
[0023]
Therefore, in the conventional MIMO mobile communication system, the PDMA base station has a problem that the DD ratios of the uplink reception powers of the multiple paths from the multiple access MIMO terminals are not uniform, and stable spatial multiplex communication cannot be realized. was there.
[0024]
Therefore, an object of the present invention is to provide a radio base apparatus, a mobile terminal apparatus, and a transmission power control method in which the uplink received power of each path in a PDMA base station is uniform and stable spatial multiplexing communication can be realized. And a transmission power control program.
[0025]
[Means for Solving the Problems]
According to one aspect of the present invention, a radio base apparatus capable of spatial multiplexing connection with a mobile terminal apparatus having a plurality of antennas includes a signal processing unit, a reception level measuring unit, a control message generating unit, and a control message transmitting unit. Means. The signal processing unit transmits and receives signals by forming a plurality of spatial paths with a plurality of antennas of the mobile terminal device. The reception level measuring means measures a reception power level of a signal received from the mobile terminal device via a plurality of spatial paths. The control message generating means controls an uplink transmission power value from at least a part of the plurality of spatial paths from the mobile terminal device such that the measured reception power levels of the plurality of spatial paths become uniform. Generate control messages. The control message transmitting means transmits the generated control message via at least a part of the plurality of spatial paths.
[0026]
Preferably, the control message generating means generates a control message for controlling the uplink transmission power values of all the spatial paths of the plurality of spatial paths, and the control message transmitting means generates the control message through all the spatial paths of the plurality of spatial paths. Send the same control message.
[0027]
Preferably, the control message generating means generates a control message for controlling an uplink transmission power value of a spatial path obtained by removing one spatial path from a plurality of spatial paths, and the control message transmitting means generates one control message from the plurality of spatial paths. The same control message is transmitted via the spatial paths excluding the number of spatial paths.
[0028]
Preferably, the wireless base device further includes a communication quality determining unit that determines a spatial path having good communication quality among the plurality of spatial paths. The control message transmitting means transmits the control message via the spatial path for which the communication quality has been determined to be good by the communication quality determining means.
[0029]
Preferably, the wireless base device further includes a communication quality determining unit that determines a plurality of spatial paths having good communication quality among the plurality of spatial paths. The control message transmitting unit divides the control message according to the plurality of spatial paths determined to have good communication quality by the communication quality determining unit, and divides the divided control message through each corresponding spatial path. To send.
[0030]
Preferably, the control message generating means individually generates a control message for controlling a transmission power value for each of the plurality of antennas of the mobile terminal device, and the control message transmitting means corresponds to each of the plurality of antennas of the mobile terminal device. And transmitting the control message.
[0031]
According to another aspect of the present invention, a mobile terminal device having a plurality of antennas includes a signal processing unit, a transmission power changing unit, and a transmission power control unit. The signal processing means transmits and receives signals using a plurality of antennas. The transmission power changing unit is configured to transmit and receive signals by forming a plurality of spatial paths between a wireless base device capable of spatial multiplexing and a plurality of antennas. Change the uplink transmission power value. The transmission power control means controls the transmission power change means in response to a control message for controlling the uplink transmission power value of the mobile terminal device received from the radio base apparatus, and changes the uplink transmission power value of at least some of the spatial paths. Let me change.
[0032]
Preferably, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of antennas, and the transmission power control unit changes an uplink transmission power value of at least a part of the plurality of antennas according to the control message. The transmission power changing means is controlled as described above.
[0033]
Preferably, the plurality of antennas are divided into a plurality of sub-array antennas, the plurality of spatial paths are formed in one-to-one correspondence with the plurality of sub-array antennas, and the transmission power control unit includes a plurality of The transmission power changing means is controlled to change the uplink transmission power value of at least a part of the sub-array antennas.
[0034]
Preferably, the transmission power changing means uniformly changes the transmission power value of each of the plurality of antennas constituting the sub-array antenna whose transmission power value is to be changed.
[0035]
Preferably, the transmission power changing means changes a transmission power value of a specific antenna among a plurality of antennas constituting a sub-array antenna whose transmission power value is to be changed.
[0036]
Preferably, the transmission power changing means changes a beam gain of a radio wave transmitted from a subarray antenna whose transmission power value is to be changed.
[0037]
According to still another aspect of the present invention, an uplink transmission power control method in a mobile terminal apparatus having a plurality of antennas and a radio base apparatus capable of spatial multiplexing connection is provided. Performing signal processing for transmitting and receiving signals by forming a spatial path; measuring a received power level of a signal received from the mobile terminal device through the plurality of spatial paths; Generating a control message for controlling an uplink transmission power value from a mobile terminal device of at least a part of the plurality of spatial paths so that a received power level for each path becomes uniform; and the generated control. Transmitting the message via at least some of the plurality of spatial paths.
[0038]
Preferably, the step of generating a control message includes generating a control message that controls an uplink transmission power value of all spatial paths of the plurality of spatial paths, and the step of transmitting the control message includes: Send the same control message over the path.
[0039]
Preferably, the step of generating a control message includes generating a control message for controlling an uplink transmission power value of a spatial path obtained by removing one spatial path from a plurality of spatial paths, and transmitting the control message includes: The same control message is transmitted via a spatial path obtained by removing one spatial path from the spatial path.
[0040]
Preferably, the transmission power control method further includes a step of determining a spatial path having good communication quality among the plurality of spatial paths. The step of transmitting the control message transmits the control message via a spatial path determined to have good communication quality.
[0041]
Preferably, the transmission power control method further includes a step of determining a plurality of spatial paths having good communication quality among the plurality of spatial paths. The step of transmitting the control message divides the control message corresponding to the plurality of spatial paths determined to have good communication quality, and transmits the divided control message via the corresponding spatial path. .
[0042]
Preferably, the step of generating a control message includes individually generating a control message for controlling a transmission power value for each of a plurality of antennas of the mobile terminal apparatus, and transmitting the control message, A corresponding control message is transmitted for each antenna.
[0043]
According to still another aspect of the present invention, an uplink transmission power control method in a mobile terminal apparatus having a plurality of antennas includes a step of performing signal processing for transmitting / receiving a signal with the plurality of antennas, and a spatial multiplexing connection. When transmitting and receiving signals by forming a plurality of spatial paths between a wireless base device and a plurality of antennas, according to a control message for controlling an uplink transmission power value of a mobile terminal device received from the wireless base device. Controlling the uplink transmission power value of at least some of the plurality of spatial paths.
[0044]
Preferably, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of antennas, and the step of controlling transmission power includes, in accordance with a control message, an uplink transmission power value of at least some of the plurality of antennas. change.
[0045]
Preferably, the plurality of antennas are divided into a plurality of sub-array antennas, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of sub-array antennas, and the step of controlling the transmission power includes: Uplink transmission power values of at least some of the plurality of subarray antennas are changed.
[0046]
Preferably, the step of controlling the transmission power uniformly changes the transmission power value of each of the plurality of antennas constituting the sub-array antenna whose transmission power value is to be changed.
[0047]
Preferably, the step of controlling the transmission power changes a transmission power value of a specific antenna among a plurality of antennas constituting a subarray antenna whose transmission power value is to be changed.
[0048]
Preferably, the step of controlling the transmission power changes a beam gain of a radio wave transmitted from a subarray antenna whose transmission power value is to be changed.
[0049]
According to still another aspect of the present invention, a transmission power control method in a mobile communication system including a mobile terminal device having a plurality of antennas and a radio base device capable of spatial multiplexing access is provided. Forming a plurality of spatial paths with the device to transmit and receive signals; and measuring a received power level of a signal received by the radio base station from the mobile terminal device through the plurality of spatial paths. Generating a control message for controlling the uplink transmission power value from the mobile terminal device, of at least some of the plurality of spatial paths, so that the received power levels of the plurality of spatial paths are uniform. Transmitting the generated control message to the mobile terminal via at least a part of the plurality of spatial paths; In the received according to the control message to control an uplink transmission power value of the mobile terminal device, and controlling the uplink transmission power values of at least some of the spatial paths of the plurality of spatial paths.
[0050]
Preferably, the step of generating a control message includes generating a control message that controls uplink transmission power values of all spatial paths of the plurality of spatial paths, and transmitting the control message includes: Send the same control message over the path.
[0051]
Preferably, the step of generating a control message includes generating a control message for controlling an uplink transmission power value of a spatial path obtained by removing one spatial path from a plurality of spatial paths, and transmitting the control message includes: The same control message is transmitted via a spatial path obtained by removing one spatial path from the spatial path.
[0052]
Preferably, the transmission power control method further includes a step of determining a spatial path having good communication quality among the plurality of spatial paths. The step of transmitting the control message transmits the control message via a spatial path determined to have good communication quality.
[0053]
Preferably, the transmission power control method further includes a step of determining a plurality of spatial paths having good communication quality among the plurality of spatial paths. The step of transmitting the control message divides the control message according to the plurality of spatial paths determined to have good communication quality, and transmits the divided control message via each corresponding spatial path. .
[0054]
Preferably, the step of generating a control message includes separately generating a control message for controlling a transmission power value for each of a plurality of antennas of the mobile terminal device, and transmitting the control message, A corresponding control message is transmitted for each antenna.
[0055]
Preferably, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of antennas, and the step of controlling transmission power includes, in accordance with a control message, an uplink transmission power value of at least some of the plurality of antennas. change.
[0056]
Preferably, the plurality of antennas are divided into a plurality of sub-array antennas, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of sub-array antennas, and the step of controlling the transmission power includes: Uplink transmission power values of at least some of the plurality of subarray antennas are changed.
[0057]
Preferably, the step of controlling the transmission power uniformly changes the transmission power value of each of the plurality of antennas constituting the sub-array antenna whose transmission power value is to be changed.
[0058]
Preferably, the step of controlling the transmission power changes a transmission power value of a specific antenna among a plurality of antennas constituting a sub-array antenna whose transmission power value is to be changed.
[0059]
Preferably, the step of controlling the transmission power changes a beam gain of a radio wave transmitted from a sub-array antenna whose transmission power value is to be changed.
[0060]
According to still another aspect of the present invention, an uplink transmission power control program in a radio base station capable of spatial multiplexing connection with a mobile terminal apparatus having a plurality of antennas includes: Performing signal processing to transmit and receive signals by forming a plurality of spatial paths therebetween; and measuring a reception power level of a signal received from the mobile terminal device through the plurality of spatial paths; Generating a control message for controlling an uplink transmission power value from a mobile terminal device of at least a part of the plurality of spatial paths so that reception power levels of the plurality of spatial paths are uniform; Transmitting the obtained control message through at least a part of the plurality of spatial paths.
[0061]
Preferably, the step of generating a control message includes generating a control message that controls an uplink transmission power value of all spatial paths of the plurality of spatial paths, and the step of transmitting the control message includes: Send the same control message over the path.
[0062]
Preferably, the step of generating a control message includes generating a control message for controlling an uplink transmission power value of a spatial path obtained by removing one spatial path from a plurality of spatial paths, and transmitting the control message includes: The same control message is transmitted via a spatial path obtained by removing one spatial path from the spatial path.
[0063]
Preferably, the transmission power control program further causes the computer to execute a step of determining a spatial path with good communication quality among the plurality of spatial paths, and the step of transmitting the control message determines that the communication quality is good. The control message is transmitted via the specified spatial path.
[0064]
Preferably, the transmission power control program further causes the computer to execute a step of determining a plurality of spatial paths having good communication quality among the plurality of spatial paths, and the step of transmitting the control message has a good communication quality. The control message is divided according to the plurality of spatial paths determined as, and the divided control messages are transmitted via the corresponding spatial paths.
[0065]
Preferably, the step of generating a control message includes separately generating a control message for controlling a transmission power value for each of a plurality of antennas of the mobile terminal device, and transmitting the control message, A corresponding control message is transmitted for each antenna.
[0066]
According to still another aspect of the present invention, an uplink transmission power control program in a mobile terminal device having a plurality of antennas includes: a computer performing signal processing for transmitting and receiving signals with the plurality of antennas; When transmitting and receiving signals by forming a plurality of spatial paths between a connectable wireless base device and a plurality of antennas, a control message for controlling an uplink transmission power value of the mobile terminal device, received from the wireless base device. Controlling the uplink transmission power values of at least some of the plurality of spatial paths.
[0067]
Preferably, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of antennas, and the step of controlling transmission power includes, in accordance with a control message, an uplink transmission power value of at least some of the plurality of antennas. change.
[0068]
Preferably, the plurality of antennas are divided into a plurality of sub-array antennas, the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of sub-array antennas, and the step of controlling the transmission power includes: Uplink transmission power values of at least some of the plurality of subarray antennas are changed.
[0069]
Preferably, the step of controlling the transmission power uniformly changes the transmission power value of each of the plurality of antennas constituting the sub-array antenna whose transmission power value is to be changed.
[0070]
Preferably, the step of controlling the transmission power changes a transmission power value of a specific antenna among a plurality of antennas constituting a subarray antenna whose transmission power value is to be changed.
[0071]
Preferably, the step of controlling the transmission power changes a beam gain of a radio wave transmitted from a subarray antenna whose transmission power value is to be changed.
[0072]
Therefore, according to the present invention, the uplink transmission power of the terminal is adjusted from the base station so that the uplink reception power of each path at the base station spatially multiplexed and connected to the terminal having a plurality of antennas becomes uniform. Since control is performed by the control message, stable spatial multiplex communication can be realized.
[0073]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.
[0074]
FIG. 1 is a functional block diagram showing a configuration of a PDMA base station compatible with the MIMO scheme according to an embodiment of the present invention. In the example shown in FIG. 1, it is assumed that the multiplicity of the PDMA base station is 2.
[0075]
With reference to FIG. 1, an array antenna composed of a plurality of antennas, for example, two antennas 1 and 2 in this example, transmits a plurality of, for example, two spatial paths from a terminal (not shown) (for example, a MIMO terminal). The received signals received via the switches are given to one inputs of multipliers 5 and 6 by switches (SW) 3 and 4, respectively.
[0076]
Oscillation signals of a predetermined frequency are given to the other inputs of the multipliers 5 and 6 from the oscillator 7, and are mixed with the reception signals of the respective antennas in the multipliers 5 and 6 so that the reception signals are frequency converted.
[0077]
The received signals output from multipliers 5 and 6 are provided to path multiplex reception processing section 10. The path multiplex reception processing unit 10 performs the above-described well-known adaptive array processing on the signals received by the antennas 1 and 2, controls the reception directivity of each path, and controls the reception data of the path 1 and the reception data of the path 2 The data is separated and extracted, output, and provided to the control unit 11. Further, the path multiplex reception processing unit 10 measures the received power value for each path and notifies the control unit 11 of the measured value.
[0078]
The control unit 11 performs necessary demodulation processing on the received data of each path, and outputs the result to an external line (not shown).
[0079]
On the other hand, when receiving the transmission data from the external line, the control unit 11 performs necessary modulation processing, and gives it to the path multiplex transmission processing unit 12 as the transmission data of the path 1 and the transmission data of the path 2. Also, the control unit 11 forms a control message for controlling the uplink transmission power value of the MIMO terminal based on the reception power value for each path received from the path multiplex reception processing unit 10, and various control messages to be described later. In an aspect, the transmission data is multiplexed.
[0080]
The path multiplex transmission processing unit 12 uses, for example, a known method such as copying the reception weight vector calculated by the path multiplex reception processing unit 10 at the time of reception to obtain a transmission weight vector, and the like. , And a transmission signal is applied to one input of each of the multipliers 8 and 9.
[0081]
An oscillation signal of a predetermined frequency is given to the other input of the multipliers 8 and 9 from the oscillator 7, and the multipliers 8 and 9 mix the transmission signals with the transmission signals of the respective paths and frequency-convert the transmission signals.
[0082]
The transmission signals output from multipliers 8 and 9 are provided to corresponding antennas 2 and 1 by switches 4 and 3 and are transmitted with corresponding transmission directivities of directing beams to corresponding antennas of a terminal (for example, a MIMO terminal). Sent out.
[0083]
In the configuration of the PDMA base station shown in the functional block diagram of FIG. 1, the functions of the path multiplex reception processing unit 10, the control unit 11, and the path multiplex transmission processing unit 12 are based on a digital signal processor (not shown) of the base station. (DSP) is realized by software.
[0084]
Next, FIG. 2 is a schematic diagram showing the basic contents of a control message transmitted from a PDMA base station to a MIMO terminal for controlling the uplink transmission power value of the MIMO terminal according to the present invention.
[0085]
The basic principle of the present invention is to monitor the received power values of each path received from the MIMO terminal having a plurality of antennas, which are received by the base station, so that the received power values of the respective paths become uniform with each other, ie, DD. The base station side attempts to control the uplink transmission power value of each path from the MIMO terminal so that the ratios become uniform.
[0086]
For this purpose, the control unit 11 creates a control message as shown in FIG. 2 and transmits it to the MIMO terminal. This message basically includes information on the number of paths for performing transmission power control, a path number for performing transmission power control, and a control power value of uplink transmission power in the path.
[0087]
The number of paths for performing transmission power control differs depending on various aspects of control as described later. When receiving such a control message from the base station, the MIMO terminal executes uplink transmission power control described later.
[0088]
[Embodiment 1]
FIG. 3 shows Embodiment 1 in which a base station transmits a transmission power control message as shown in FIG. 2 to a MIMO terminal when the PDMA base station shown in FIG. 1 is spatially multiplexed with a multiple antenna MIMO terminal. FIG. 4 is a flowchart showing a method according to the present invention.
[0089]
In the flowchart of each embodiment of the control of the base station described below, a DSP (not shown) reads out a program including each step of each flowchart from a memory (not shown) and executes it. These programs can be externally installed in the base station.
[0090]
Referring to FIG. 3, in the functional block diagram of FIG. 1, reception processing by adaptive array processing is executed in path multiplex reception processing section 10 realized by DSP (step S1), and reception power of each path from MIMO terminal is obtained. A value is detected (step S2).
[0091]
The detected received power value is given to the control unit 11 implemented by a DSP in the functional block diagram of FIG. 1, and it is determined whether there is a large variation in the received power among a plurality of paths (step S3). ).
[0092]
If there is no particularly large variation, the control unit 11 proceeds to a normal reception process. In step S4, the control unit 11 controls the uplink transmission power of each path such that the reception power values of all paths are equal to each other based on the detected reception power value of each path described above. The power amount is calculated, and one control message for all paths is created as shown in FIG.
[0093]
Then, the same control message as shown in FIG. 2 is transmitted from the PDMA base station to the MIMO terminal via each of the plurality of paths. After that, the control unit 11 proceeds to a normal process.
[0094]
The MIMO terminal receiving such a control message can decode the message and control the transmission power value for each path based on the content thereof. As a result, the reception power value of each path on the base station side can be reduced. They can be uniform to each other. The processing in the MIMO terminal will be described later.
[0095]
In addition, since the control message is transmitted using all the paths, the message can be reliably transmitted to the MIMO terminal.
[0096]
[Embodiment 2]
FIG. 4 shows a second embodiment in which the base station transmits a transmission power control message as shown in FIG. 2 to a MIMO terminal when the PDMA base station shown in FIG. 1 is spatially multiplexed with a multiple antenna MIMO terminal. FIG. 4 is a flowchart showing a method according to the present invention. In the second embodiment, the total number of paths between the MIMO terminal and the PDMA terminal is M (M is a positive integer).
[0097]
Referring to FIG. 4, in the functional block diagram of FIG. 1, reception processing by adaptive array processing is executed by path multiplex reception processing section 10 realized by DSP (step S1), and reception power of each path from MIMO terminal is obtained. A value is detected (step S2).
[0098]
The detected received power value is given to the control unit 11 implemented by a DSP in the functional block diagram of FIG. 1, and it is determined whether there is a large variation in the received power among a plurality of paths (step S3). ).
[0099]
If there is no particularly large variation, the control unit 11 proceeds to a normal reception process. In step S5, the control unit 11 controls the received power values of all the paths based on the detected received power values of the respective paths so that the received power values of all the paths are equal to each other, that is, of the M paths, The control power amount of the uplink transmission power of each of the (M-1) paths is calculated so that the reception power value of the remaining (M-1) paths is adjusted to the reception power value of the specific path, One control message as shown in FIG. 2 for the path of M-1) is created.
[0100]
Then, the same control message as shown in FIG. 2 is transmitted from the PDMA base station to the MIMO terminal via each of the (M-1) paths. After that, the control unit 11 proceeds to a normal process.
[0101]
The MIMO terminal receiving such a control message decodes the message, and adjusts the transmission power value of each of the (M-1) paths to the reception power value of the other one path based on the content of the message. So that the received power values of the respective paths on the base station side can be made uniform to each other. The processing in the MIMO terminal will be described later.
[0102]
[Embodiment 3]
FIG. 5 shows Embodiment 3 in which a base station transmits a transmission power control message as shown in FIG. 2 to a MIMO terminal when PDMA base station shown in FIG. 1 is spatially multiplexed with a multiple antenna MIMO terminal. FIG. 4 is a flowchart showing a method according to the present invention.
[0103]
Referring to FIG. 5, in the functional block diagram of FIG. 1, reception processing by adaptive array processing is executed in path multiplex reception processing section 10 realized by DSP (step S1), and reception power of each path from MIMO terminal is obtained. A value is detected (step S2).
[0104]
The detected received power value is given to the control unit 11 implemented by a DSP in the functional block diagram of FIG. 1, and it is determined whether there is a large variation in the received power among a plurality of paths (step S3). ).
[0105]
In particular, if there is no large variation, the control unit 11 proceeds to a normal reception process.
[0106]
In step S6, the control unit 11 determines the communication quality of each of the plurality of paths from the MIMO terminal, and selects a path having a high communication quality among them. The communication quality is determined based on, for example, the following criteria.
[0107]
For example, the control unit 11 calculates the number of reception errors in the past predetermined number of frames for each path, and selects a path with the least number of reception errors as a path with high communication quality.
[0108]
Alternatively, immediately before transmitting the transmission power control message, the control unit 11 selects, as the high communication quality path, the path indicating the maximum reception power value among the reception power values of the paths received by the base station.
[0109]
Next, in step S7, the control unit 11 performs the uplink transmission of each path such that the received power values of all paths are equal to each other based on the detected received power value of each path described above. The control power amount of the power is calculated, and one control message for all the paths is created as shown in FIG.
[0110]
Then, a control message as shown in FIG. 2 is transmitted from the PDMA base station to the MIMO terminal via the high communication quality path selected in step S6. After that, the control unit 11 proceeds to a normal process.
[0111]
The MIMO terminal receiving such a control message can decode the message and control the transmission power value for each path based on the content thereof. As a result, the reception power value of each path on the base station side can be reduced. They can be uniform to each other. The processing in the MIMO terminal will be described later.
[0112]
In this embodiment, since the control message is transmitted only to the path with high communication quality, the message can be surely transmitted to the MIMO terminal.
[0113]
In a path that does not transmit a control message, the amount of data that can be transferred can be increased by the absence of the control message.
[0114]
[Embodiment 4]
FIG. 6 shows Embodiment 4 in which the base station transmits a transmission power control message as shown in FIG. 2 to a MIMO terminal when the PDMA base station shown in FIG. 1 is spatially multiplexed with a multiple antenna MIMO terminal. FIG. 4 is a flowchart showing a method according to the present invention.
[0115]
Referring to FIG. 6, in the functional block diagram of FIG. 1, reception processing by adaptive array processing is executed in path multiplex reception processing section 10 realized by DSP (step S1), and reception power of each path from MIMO terminal is obtained. A value is detected (step S2).
[0116]
The detected received power value is given to the control unit 11 implemented by a DSP in the functional block diagram of FIG. 1, and it is determined whether there is a large variation in the received power among a plurality of paths (step S3). ).
[0117]
If there is no particularly large variation, the control unit 11 proceeds to a normal reception process.
[0118]
In step S8, the control unit 11 determines the communication quality of each of the plurality of paths from the MIMO terminal, and selects the plurality of paths from the one with the highest communication quality. The criterion for determining the communication quality is as described in relation to step S6 of the third embodiment in FIG.
[0119]
For example, the control unit 11 calculates the number of received errors in the past predetermined number of frames for each path, and selects a plurality of paths from the one with the least number of received errors as paths with high communication quality.
[0120]
Alternatively, immediately before transmitting the transmission power control message, the control unit 11 sets a plurality of paths from the one having the highest reception power value among the reception power values of the paths received by the base station as paths with high communication quality. select.
[0121]
Next, in step S8, the control unit 11 performs uplink transmission of each path such that the received power values of all paths are equal to each other based on the detected received power value of each path described above. The control power amount of the power is calculated, and one control message for all the paths is created as shown in FIG.
[0122]
Then, the control unit 11 divides the formed one control message into a plurality of blocks corresponding to the plurality of paths of high communication quality selected in step S6, and divides the divided message into a plurality of selected high-quality messages. The signal is transmitted to the MIMO terminal via each of the communication quality paths. After that, the control unit 11 proceeds to a normal process.
[0123]
The MIMO terminal receiving such a control message can decode the message and control the transmission power value for each path based on the content thereof. As a result, the reception power value of each path on the base station side can be reduced. They can be uniform to each other. The processing in the MIMO terminal will be described later.
[0124]
In this embodiment, since the control message is transmitted only to a plurality of paths with high communication quality, the message can be surely transmitted to the MIMO terminal.
[0125]
In a path that does not transmit a control message, the amount of data that can be transferred can be increased by the absence of the control message.
[0126]
[Embodiment 5]
FIG. 7 is a flowchart showing a method according to Embodiment 5 in which the base station transmits a transmission power control message to a MIMO terminal when the PDMA base station shown in FIG. 1 is spatially multiplexed with a multiple antenna MIMO terminal. It is.
[0127]
In the fifth embodiment, the control message does not cover the power control information of a plurality of paths with one message as shown in FIG. 2, but for each path, the number of the path and the control power It is assumed that a control message consisting of a value is created.
[0128]
Referring to FIG. 7, in the functional block diagram of FIG. 1, reception processing by adaptive array processing is executed in path multiplex reception processing section 10 realized by DSP (step S1), and reception power of each path from MIMO terminal is obtained. A value is detected (step S2).
[0129]
The detected received power value is given to the control unit 11 implemented by a DSP in the functional block diagram of FIG. 1, and it is determined whether there is a large variation in the received power among a plurality of paths (step S3). ).
[0130]
If there is no particularly large variation, the control unit 11 proceeds to the normal reception processing, and if there is a large variation, the process proceeds to step S9. In step S9, the control unit 11 controls the uplink transmission power of each path based on the detected reception power value of each path described above so that the reception power values of all paths are equal to each other. The amount of power is calculated, and a plurality of control messages individually targeting each path are created as described above.
[0131]
Then, while directing the transmission directivity from the PDMA base station to the corresponding antenna of the MIMO terminal by the path multiplex transmission processing unit 12, a unique transmission power control message that differs for each path via each of the plurality of paths is transmitted to the MIMO terminal. Send. After that, the control unit 11 proceeds to a normal process.
[0132]
A MIMO terminal that receives such a different control message for each path on each antenna can decode the message and control the transmission power value for each path based on the content thereof. As a result, the base station side The received power value of each path can be made uniform to each other. The processing in the MIMO terminal will be described later.
[0133]
Next, FIG. 8 is a functional block diagram showing a configuration of a MIMO terminal according to the embodiment of the present invention. It is assumed that the terminal shown in FIG. 8 does not perform adaptive array reception.
[0134]
Referring to FIG. 8, a MIMO terminal according to an embodiment of the present invention includes a plurality of, for example, two antennas 21a and 21b in this example, and a plurality of, for example, two spaces in this example from a PDMA base station not shown. The signal transmitted via each path is received.
[0135]
For example, a signal on path 1 from the PDMA base station is transmitted with a transmission directivity in which a beam is directed to antenna 21a of the MIMO terminal, and received by antenna 21a.
[0136]
The signal received by the antenna 21a is provided to one input of a multiplier 24a by a switch (SW) 22a.
[0137]
An oscillation signal of a predetermined frequency is given from the oscillator 23a to the other input of the multiplier 24a, and the multiplier 24a mixes the oscillation signal with the reception signal of the antenna 21a to frequency-convert the reception signal.
[0138]
The received signal output from multiplier 24a is provided to path 1 transmission / reception processing unit 26a. The path 1 transmission / reception processing unit 26a performs a known reception process on the signal received by the antenna 21a, and supplies the signal to the control unit 27 as reception data of the path 1.
[0139]
The control unit 27 performs a necessary demodulation process on the reception data of the path 1 and outputs the result to an external line (not shown).
[0140]
Similarly, a signal on path 2 from the PDMA base station is transmitted with a transmission directivity in which a beam is directed to antenna 21b of the MIMO terminal, and received by antenna 21b.
[0141]
The signal received by the antenna 21b is provided to one input of a multiplier 24b by a switch (SW) 22b.
[0142]
An oscillation signal of a predetermined frequency is given from the oscillator 23b to the other input of the multiplier 24b, and the multiplier 24b mixes the oscillation signal with the reception signal of the antenna 21b to frequency-convert the reception signal.
[0143]
The received signal output from multiplier 24b is provided to path 2 transmission / reception processing unit 26b. The path 2 transmission / reception processing unit 26b performs a well-known reception process on the signal received by the antenna 21b, and provides the signal to the control unit 27 as reception data of path 2.
[0144]
The control unit 27 performs necessary demodulation processing on the reception data of the path 2 and outputs the result to an external line (not shown).
[0145]
Also, the control unit 27 multiplexes the received data received from the PDMA base station and transmits the multiplexed data, for example, as shown in FIG. The control message is decoded to obtain information on the control amount of the transmission power value of each path.
[0146]
On the other hand, when receiving the transmission data from the external line, the control unit 27 performs necessary modulation processing, and transmits the data to the path 1 transmission / reception processing unit 26a and the path 2 transmission / reception processing unit 26b as transmission data of the path 1 and transmission data of the path 2. Give each.
[0147]
Here, the control unit 27 controls the transmission power value from the antenna corresponding to each path based on the control amount of the transmission power value of each path obtained by decoding the transmission power control message as described above. And the path 1 transmission / reception processing unit 26a and the path 2 transmission / reception processing unit 26b.
[0148]
The path 1 transmission / reception processing unit 26a controls the transmission directivity of the transmission data of the path 1 by using a known method such as copying a reception weight vector calculated at the time of reception to obtain a transmission weight vector. The transmission signal is applied to one input of a multiplier 25a.
[0149]
An oscillation signal of a predetermined frequency is given to the other input of the multiplier 25a from the oscillator 23a, and the multiplier 25a mixes the oscillation signal with the transmission signal of the path 1 and frequency-converts the transmission signal.
[0150]
The transmission signal output from the multiplier 25a is provided to the corresponding antenna 21a by the switch 22a, and is transmitted omnidirectionally.
[0151]
The path 2 transmission / reception processing unit 26b controls the transmission directivity of the transmission data of the path 2 by using a known method such as copying a reception weight vector calculated at the time of reception to obtain a transmission weight vector. The transmission signal is applied to one input of a multiplier 25b.
[0152]
An oscillation signal of a predetermined frequency is given from the oscillator 23b to the other input of the multiplier 25b, and is mixed with the transmission signal of the path 2 in the multiplier 25b, and the transmission signal is frequency-converted.
[0153]
The transmission signal output from the multiplier 25b is provided to the corresponding antenna 21b by the switch 22b, and is transmitted omnidirectionally.
[0154]
In the configuration of the MIMO terminal shown in the functional block diagram of FIG. 8, the functions of the path 1 transmission / reception processing unit 26a, the path 2 transmission / reception control unit 26b, and the control unit 27 are realized by software by a DSP (not shown) of the MIMO terminal. .
[0155]
Embodiment 6
FIG. 9 shows a case where the MIMO terminal shown in FIG. 8 is spatially multiplexed and connected to the PDMA base station as shown in FIG. FIG. 17 is a flowchart showing a method according to Embodiment 6 of performing uplink transmission power control according to a transmission control message.
[0156]
In the flowchart of each embodiment of the terminal control described below, a DSP (not shown) reads a program including each step of each flowchart from a memory (not shown) and executes the program. These programs can be installed in the terminal from the outside.
[0157]
Referring to FIG. 9, in the functional block diagram of FIG. 8, reception processing is executed by path 1 transmission / reception processing unit 26a and path 2 transmission / reception processing unit 26b realized by the DSP (step S11).
[0158]
Next, the control unit 27 implemented by the DSP in the functional block diagram of FIG. 8 adds the uplink transmission power from the base station to the reception data of each path in, for example, any one of the above-described first to fifth embodiments. It is determined whether a control message is included (step S12).
[0159]
If the message is not included, the control unit 27 proceeds to a normal reception process. If the message is included, the control unit 27 proceeds to step S13. In step S13, the control unit 27 controls the uplink transmission power value of the antenna corresponding to the designated path according to the content of the received transmission power control message. After that, the control unit 27 proceeds to a normal process.
[0160]
As described above, the MIMO terminal that has received the transmission power control message from the PDMA base station can decode the message and control the uplink transmission power for each antenna, that is, for each path based on the content of the message. The received power value of each path at the base station can be made uniform.
[0161]
Next, FIG. 10 is a functional block diagram showing a configuration of a MIMO terminal capable of adaptive array reception according to an embodiment of the present invention.
[0162]
Referring to FIG. 10, a MIMO terminal capable of adaptive array reception according to an embodiment of the present invention includes a plurality of sub-array antennas, for example, a first sub-array antenna including antennas 31a and 32a and antennas 31b and 32b. The second sub-array antenna receives a plurality of signals, for example, two signals transmitted in this example via two spatial paths from a PDMA base station (not shown).
[0163]
It should be noted that each of the first and second sub-array antennas described above is replaced with a sub-array in the sense of a partial array antenna with respect to the array antenna constituted by the entire antennas 31a, 32a, 31b and 32b of the MIMO terminal in FIG. This is called an antenna.
[0164]
For example, a signal on path 1 from the PDMA base station is transmitted with transmission directivity in which a beam is directed to first sub-array antennas 31a and 32a of the MIMO terminal, and received by first sub-array antennas 31a and 32a.
[0165]
Received signals received by antennas 31a and 32a constituting the first sub-array antenna are provided to one input of multipliers 35a and 36a by switches (SW) 33a and 34a, respectively.
[0166]
Oscillation signals of a predetermined frequency are given to the other inputs of the multipliers 35a and 36a from the oscillator 37a, and are mixed with the reception signals of the respective antennas in the multipliers 35a and 36a, and the reception signals are frequency-converted.
[0167]
The received signals output from the multipliers 35a and 36a are provided to the path 1 array reception processing unit 40a. The path 1 array reception processing unit 40a performs the above-described well-known adaptive array processing on the signals received by the antennas 31a and 32a, controls the reception directivity of the path 1, and separates and extracts the reception data of the path 1. And outputs it to the control unit 41.
[0168]
The control unit 41 performs necessary demodulation processing on the reception data of the path 1 and outputs the result to an external line (not shown).
[0169]
Similarly, the signal of path 2 from the PDMA base station is transmitted with the transmission directivity in which the beam is directed to the second sub-array antennas 31b and 32b of the MIMO terminal, and received by the second sub-array antennas 31b and 32b. .
[0170]
Received signals received by antennas 31b and 32b constituting the second sub-array antenna are provided to one input of multipliers 35b and 36b by switches (SW) 33b and 34b, respectively.
[0171]
Oscillation signals of a predetermined frequency are given to the other inputs of the multipliers 35b and 36b from the oscillator 37b, and the multipliers 35b and 36b mix the received signals with the reception signals of the respective antennas and frequency-convert the reception signals.
[0172]
The received signals output from multipliers 35b and 36b are provided to path 2 array reception processing unit 40b. The path 2 array reception processing unit 40b performs the above-described well-known adaptive array processing on the signals received by the antennas 31b and 32b, controls the reception directivity of the path 2, and separates and extracts the reception data of the path 2. And outputs it to the control unit 41.
[0173]
The control unit 41 performs necessary demodulation processing on the reception data of the path 2 and outputs the result to an external line (not shown).
[0174]
Also, the control unit 41 transmits, for example, the uplink transmission power as shown in FIG. 2 multiplexed with the received data received from the PDMA base station and transmitted by the method of any of the above-described first to fifth embodiments. The control message is decoded to obtain information on the control amount of the transmission power value of each path.
[0175]
On the other hand, when receiving the transmission data from the external line, the control unit 41 performs necessary modulation processing, and converts the data into a path 1 array transmission processing unit 42a and a path 2 array transmission processing unit as path 1 transmission data and path 2 transmission data. 42b.
Here, the control unit 41 controls the transmission power value from the sub-array antenna corresponding to each path based on the control amount of the transmission power value of each path obtained by decoding the transmission power control message as described above. The path 1 array transmission processing unit 42a and the path 2 array transmission processing unit 42b are controlled as described above.
[0176]
The path 1 array transmission processing unit 42a uses a well-known method such as copying the reception weight vector calculated by the path 1 array reception processing unit 40a at the time of reception into a transmission weight vector. After controlling the transmission directivity, the transmission signal of path 1 is given to one input of each of multipliers 38a and 39a.
[0177]
The other input of the multipliers 38a and 39a is supplied with an oscillating signal of a predetermined frequency from the oscillator 37a, and is mixed with the transmission signal of each path in the multipliers 38a and 39a to frequency-convert the transmission signal.
[0178]
The transmission signals of path 1 output from the multipliers 38a and 39a are supplied to the corresponding first sub-array antennas 32a and 31a by the switches 34a and 33a, and the transmission directivity for directing the beam to the array antenna of the PDMA base station is provided. It is sent along with it.
[0179]
The path 2 array transmission processing unit 42b uses a well-known method such as copying the reception weight vector calculated by the path 2 array reception processing unit 40b at the time of reception into a transmission weight vector. After controlling the transmission directivity, the transmission signal of path 2 is given to one input of each of multipliers 38b and 39b.
[0180]
The other input of the multipliers 38b and 39b is supplied with an oscillation signal of a predetermined frequency from the oscillator 37b, and is mixed with the transmission signal of each path in the multipliers 38b and 39b so that the transmission signal is frequency-converted.
[0181]
The transmission signals of path 2 output from the multipliers 38b and 39b are provided to the corresponding second array antennas 32b and 31b by the switches 34b and 33b, and the transmission directivity for directing the beam to the array antenna of the PDMA base station is provided. It is sent along with it.
[0182]
In the configuration of the PDMA base station shown in the functional block diagram of FIG. 10, the path 1 array reception processing unit 40a, the path 1 array transmission processing unit 42a, the path 2 array reception processing unit 40b, the path 2 array transmission processing unit 42b, and The function of the control unit 41 is realized by software by a DSP (not shown) of the MIMO terminal.
[0183]
Embodiment 7
FIG. 11 shows a case where the MIMO terminal shown in FIG. 10 is spatially multiplexed and connected to the PDMA base station as shown in FIG. 1 and received from the base station by various methods of the above-described first to fifth embodiments. FIG. 21 is a flowchart showing a method according to Embodiment 7 of performing uplink transmission power control in response to a transmission control message.
[0184]
Referring to FIG. 11, in the functional block diagram of FIG. 10, reception processing is executed by path 1 array reception processing unit 40a and path 2 array reception processing unit 40b realized by the DSP (step S11).
[0185]
Next, the control unit 41 realized by the DSP in the functional block diagram of FIG. 10 adds the uplink transmission power from the base station to the reception data of each path in, for example, any one of the above-described first to fifth embodiments. It is determined whether a control message is included (step S12).
[0186]
If the message is not included, the control unit 41 proceeds to the normal receiving process. If the message is included, the control unit 41 proceeds to step S14. In step S14, the control unit 41 controls the uplink transmission power value of the sub-array antenna corresponding to the designated path according to the content of the received transmission power control message.
[0187]
In Embodiment 7 of FIG. 11, in order to realize a control value of the transmission power of the path specified by the control message from the base station, the transmission power of each antenna constituting the sub-array antenna corresponding to the path is uniformly set. Control. For example, assuming that the power control amount of the path is X watts and the number of antennas constituting the sub-array antenna corresponding to the path is N, the power control amount per antenna is X / N watts. In step S14 of FIG. 11, the transmission power of the entire sub-array antenna of the designated path is controlled. After that, the control unit 41 proceeds to a normal process.
[0188]
As described above, the MIMO terminal that has received the transmission power control message from the PDMA base station can decode the message and control the uplink transmission power for each sub-array antenna, that is, for each path based on the content of the message. As a result, the received power value of each path on the base station side can be made uniform.
[0189]
Embodiment 8
FIG. 12 shows a case where the MIMO terminal shown in FIG. 10 is spatially multiplexed and connected to a PDMA base station as shown in FIG. 1 and received from the base station by various methods of the above-described first to fifth embodiments. FIG. 23 is a flowchart showing a method according to Embodiment 8 of performing uplink transmission power control according to a transmission control message.
[0190]
Referring to FIG. 12, in the functional block diagram of FIG. 10, reception processing is executed by path 1 array reception processing unit 40a and path 2 array reception processing unit 40b realized by the DSP (step S11).
[0191]
Next, the control unit 41 realized by the DSP in the functional block diagram of FIG. 10 adds the uplink transmission power from the base station to the reception data of each path in, for example, any one of the above-described first to fifth embodiments. It is determined whether a control message is included (step S12).
[0192]
If the message is not included, the control unit 41 proceeds to a normal reception process. If the message is included, the control unit 41 proceeds to step S15. In step S15, the control unit 41 controls the uplink transmission power value of the sub-array antenna corresponding to the designated path according to the content of the received transmission power control message.
[0193]
In the eighth embodiment of FIG. 12, in order to realize a control value of transmission power of a path specified by a control message from a base station, a part of a plurality of antennas constituting a sub-array antenna corresponding to the path is required. Only the transmission power of the antenna is controlled. For example, if the power control amount of the path is X watts and the number of antennas forming the sub-array antenna corresponding to the path is N, for example, power control of X watts is performed by only one specific antenna among the N antennas. Shall do. In step S15 of FIG. 12, the transmission power of a part of the sub-array antenna of the path designated in this way is controlled. After that, the control unit 41 proceeds to a normal process.
[0194]
As described above, the MIMO terminal that has received the transmission power control message from the PDMA base station can decode the message and control the uplink transmission power for each sub-array antenna, that is, for each path based on the content of the message. As a result, the received power value of each path on the base station side can be made uniform.
[0195]
Embodiment 9
FIG. 13 shows a case where the MIMO terminal shown in FIG. 10 is spatially multiplexed and connected to the PDMA base station as shown in FIG. 1 and received from the base station by various methods of the above-described first to fifth embodiments. FIG. 25 is a flowchart showing a method according to Embodiment 9 for performing uplink transmission power control according to a transmission control message.
[0196]
Referring to FIG. 13, in the functional block diagram of FIG. 10, reception processing is executed by path 1 array reception processing unit 40a and path 2 array reception processing unit 40b realized by the DSP (step S11).
[0197]
Next, the control unit 41 realized by the DSP in the functional block diagram of FIG. 10 adds the uplink transmission power from the base station to the reception data of each path in, for example, any one of the above-described first to fifth embodiments. It is determined whether a control message is included (step S12).
[0198]
If the message is not included, the control unit 41 proceeds to a normal reception process. If the message is included, the control unit 41 proceeds to step S16. In step S16, the control unit 41 controls the uplink transmission power value of the sub-array antenna corresponding to the designated path according to the content of the received transmission power control message.
[0199]
In the ninth embodiment of FIG. 13, in order to realize a control value of the transmission power of a path specified by a control message from a base station, the transmission directivity of a sub-array antenna corresponding to the path is controlled.
[0200]
That is, by controlling the transmission weight on the terminal side so as to control the beam gain of the radio wave transmitted from the subarray antenna to the array antenna of the PDMA base station, the received power value from the MIMO terminal at the base station changes. . In step S16 of FIG. 13, by controlling the transmission weight of the sub-array antenna of the path designated in this way, uplink transmission power control is eventually realized. After that, the control unit 41 proceeds to a normal process.
[0201]
Hereinafter, a method for controlling the beam gain of the transmission radio wave radiated from the sub-array antenna of the terminal to the base station will be described. The following control method (calculation) is executed by software by a DSP (not shown) constituting each of the processing units 40a, 42a, 40b, 42b and the control unit 41 in the functional block diagram of FIG.
[0202]
The ninth embodiment employs a method of estimating a response vector from a received signal and further estimating a transmission weight from a response vector, instead of copying the reception weight as it is as the transmission weight. The basic principle of such a method is well known, for example, as disclosed in International Publication WO00 / 79702 and Japanese Patent Application Laid-Open No. 2002-43995.
[0203]
Further, in the example of FIG. 10, each sub-array antenna is composed of two antennas. However, in the following description, a sub-array antenna composed of four antennas will be described for convenience of explanation.
[0204]
In the following description, Xi (t) is a received signal of the ith antenna of the sub-array antenna of the MIMO terminal, S1 (t) is a signal from a base station that is a desired station for the MIMO terminal, and S2 (t) Is a received signal from the interfering station to the MIMO terminal, and Hij is a response vector of a signal from the j-th station received by the i-th antenna.
[0205]
Here, the transmission weight of the sub-array antenna is (W1, W2, W3, W4), and the radiation signal in the interference direction is Y2 (t).
[0206]
This radiation signal Y2 (t) is represented by the following equation.
Y2 (t) = H12 · W1 · S2 (t) + H22 · W2 · S2 (t) + H32 · W3 · S2 (t) + H42 · W4 · S2 (t)
= (H12 · W1 + H22 · W2 + H32 · W3 + H42 · W4) · S2 (t)
From this equation, using a transmission weight that satisfies (H12 · W1 + H22 · W2 + H32 · W3 + H42 · W4) = 0, the radiated signal in the interference direction becomes Y2 (t) = 0 and is minimized. The transmission weight that achieves this is referred to as a first transmission weight.
[0207]
An algorithm for calculating such weights is an algorithm for learning weights by a steepest descent method MMSE (Minimum Mean Square Error) based on the square of an error between the adaptive array output signal and the reference signal. An adaptive array algorithm such as a Recursive Least Squares algorithm, an LMS (Least Mean Square) algorithm, and an SMI (Sample Matrix Inversion) algorithm is used. Such RLS algorithm, LMS algorithm, SMI algorithm and the like are well-known techniques in the field of adaptive array processing.
[0208]
In the case of the above-mentioned first transmission weight, the amplitude of each weight is different, and the phase is not necessarily opposite to the phase of the response vector of the desired station, so that the radiation power toward the desired station is maximized immediately. It is not done.
[0209]
Therefore, the following method can be considered as a method for maximizing the radiated power in a desired station direction.
[0210]
Here, the received signal of each antenna is represented as follows.
X1 (t) = H11 · S1 (t) + H12 · S2 (t)
X2 (t) = H21 · S1 (t) + H22 · S2 (t)
X3 (t) = H31 · S1 (t) + H32 · S2 (t)
X4 (t) = H41 · S1 (t) + H42 · S2 (t)
If the terminal can receive the desired signal from the desired base station while suppressing the interference by the adaptive array reception, the desired signal S1 (t) can be demodulated. Then, the response vector Hi1 of the signal from the desired station for all antennas can be estimated.
[0211]
The estimation method is to calculate an ensemble average (time average) of the received signal Xi (t) and the demodulated signal S1 (t).
[0212]
E [Xi (t) · S1 (t) ^* ] = Hi1 · E [S1 (t) · S1 (t) ^* ] + Hi2 · E [S2 (t) · S1 (t) ^* ]
Note that E [•] indicates an ensemble averaging operation, and * indicates a conjugate complex operation.
[0213]
Here, the ensemble average of the same signals is E [S1 (t) · S1 (t) ^* ] = 1, and the ensemble average of different signals is E [S2 (t) .S1 (t) if the average time is long enough. ^* ] = 0.
[0214]
Therefore, E [Xi (t) · S1 (t) ^* ] = Hi1, and the response vector can be estimated. At this time, the transmission weight is determined by the following equation.
[0215]
W1 = H11 ^* / | Hi1 |
W2 = H21 ^* / | Hi1 |
W3 = H31 ^* / | Hi1 |
W4 = H41 ^* / | Hi1 |
Here, assuming that Hi1 = Ai1 · exp (jθi1), each weight is expressed as follows. A represents the amplitude of the response vector.
[0216]
W1 = H11 ^* /|Hi1|=A11.exp(-jθ11)/A11=
exp (-jθ11)
W2 = H21 ^* /|Hi1|=A21.exp(-jθ21)/A21=
exp (-jθ21)
W3 = H31 ^* /|Hi1|=A31.exp(-jθ31)/A31=
exp (-jθ31)
W4 = H41 ^* / | Hi1 | = A41 · exp (−jθ41) / A41 =
exp (-jθ41)
Therefore, each transmission weight has only a phase component.
[0219]
When a signal is transmitted from the sub-array antenna of the terminal using such a transmission weight, a radiation signal Y1 (t) toward the desired station is represented by the following equation.
[0218]

Since A is an amplitude, is always a positive value, and is in phase (that is, the direction of the vector is the same on the complex plane), the signal in the direction of the desired station is maximized, ie, , The intensity of the beam is maximized. However, in this case, the signal is also radiated toward the interference station. The transmission weight that achieves this is referred to as a second transmission weight.
[0219]
By setting an appropriate interpolated value of the first transmission weight and the second transmission weight as the transmission weight, it is possible to appropriately control the transmission power toward the desired base station.
[0220]
As described above, the MIMO terminal that has received the transmission power control message from the PDMA base station can decode the message and control the uplink transmission power for each sub-array antenna, that is, for each path based on the content of the message. As a result, the received power value of each path on the base station side can be made uniform.
[0221]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0222]
【The invention's effect】
As described above, according to the present invention, when a terminal having a plurality of antennas and a base station capable of spatial multiplexing are performing multiplex communication via a plurality of paths, uplink reception of each path at the base station is performed. The uplink transmission power from the terminal is controlled by a control message from the base station so that the power becomes uniform. This makes it possible to make the received power of each path in the base station equal to each other, thereby realizing stable spatial multiplexing communication.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a configuration of a PDMA base station according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing contents of a transmission power control message according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a transmission power control method according to Embodiment 1 of the present invention.
FIG. 4 is a flowchart showing a transmission power control method according to Embodiment 2 of the present invention.
FIG. 5 is a flowchart showing a transmission power control method according to Embodiment 3 of the present invention.
FIG. 6 is a flowchart showing a transmission power control method according to Embodiment 4 of the present invention.
FIG. 7 is a flowchart showing a transmission power control method according to Embodiment 5 of the present invention.
FIG. 8 is a functional block diagram showing a configuration of a MIMO terminal according to the embodiment of the present invention.
FIG. 9 is a flowchart showing a transmission power control method according to Embodiment 6 of the present invention.
FIG. 10 is a functional block diagram showing another configuration of the MIMO terminal according to the embodiment of the present invention.
FIG. 11 is a flowchart showing a transmission power control method according to Embodiment 7 of the present invention.
FIG. 12 is a flowchart showing a transmission power control method according to Embodiment 8 of the present invention.
FIG. 13 is a flowchart showing a transmission power control method according to Embodiment 9 of the present invention.
FIG. 14 is a conceptual diagram schematically showing a connection mode of a conventional one-user one-pass system.
FIG. 15 is a conceptual diagram schematically showing a connection mode of a one-user four-pass system by the MIMO system.
[Explanation of symbols]
1, 2, 21a, 21b, 31a, 32a, 31b, 32b antenna, 3, 4, 22a, 22b, 33a, 34a, 33b, 34b switch, 5, 6, 8, 9, 24a, 25a, 24b, 25b, 35a, 36a, 35b, 36b, 38a, 39a, 38b, 39b Multiplier, 7, 23a, 23b, 37a, 37b oscillator, 10-pass multiplex reception processing unit, 11, 27, 41 control unit, 12-pass multiplex transmission processing unit , 26a path 1 transmission / reception processing section, 26b path 2 transmission / reception processing section, 40a path 1 array reception processing section, 40b path 2 array reception processing section, 42a path 1 array transmission processing section, 42b path 2 array transmission processing section.

Claims (17)

A wireless base station capable of spatial multiplexing connection with a mobile terminal apparatus having a plurality of antennas,
Signal processing means for transmitting and receiving signals by forming a plurality of spatial paths between the plurality of antennas of the mobile terminal device,
Reception level measuring means for measuring a reception power level of a signal received from the mobile terminal device via the plurality of spatial paths,
A control message for controlling an uplink transmission power value from the mobile terminal device of at least a part of the plurality of spatial paths so that the measured reception power levels of the plurality of spatial paths become uniform. Control message generating means for generating
A control message transmitting unit that transmits the generated control message via at least a part of the plurality of spatial paths. The control message generating means generates a control message that controls uplink transmission power values of all spatial paths of the plurality of spatial paths,
The radio base station apparatus according to claim 1, wherein the control message transmitting unit transmits the same control message via all of the plurality of spatial paths. The control message generating means generates a control message for controlling an uplink transmission power value of a spatial path obtained by removing one spatial path from the plurality of spatial paths,
The radio base station apparatus according to claim 1, wherein the control message transmitting unit transmits the same control message via a spatial path obtained by removing the one spatial path from the plurality of spatial paths. The communication apparatus further includes a communication quality determination unit that determines a space path having good communication quality among the plurality of space paths,
The radio base station apparatus according to claim 1, wherein the control message transmitting unit transmits the control message via a spatial path determined as having good communication quality by the communication quality determining unit. Among the plurality of spatial paths, further includes a communication quality determination unit that determines a plurality of spatial paths having good communication quality,
The control message transmitting unit divides the control message in accordance with a plurality of spatial paths for which communication quality has been determined to be good by the communication quality determining unit, and assigns the divided control messages to respective spaces. The radio base station according to claim 1, wherein the radio base station transmits the data via a path. The control message generating means, for each of the plurality of antennas of the mobile terminal device, individually generates a control message for controlling a transmission power value,
The radio base apparatus according to claim 1, wherein the control message transmitting unit transmits the corresponding control message for each of the plurality of antennas of the mobile terminal apparatus. A mobile terminal device having a plurality of antennas,
Signal processing means for transmitting and receiving signals with the plurality of antennas,
When transmitting and receiving signals by forming a plurality of spatial paths between a radio base apparatus capable of spatial multiplexing and the plurality of antennas, an uplink transmission power value of at least a part of the plurality of spatial paths Transmission power changing means for changing
In response to a control message for controlling an uplink transmission power value of the mobile terminal device received from the wireless base device, the transmission power changing unit is controlled to change an uplink transmission power value of the at least some spatial paths. A mobile terminal device comprising: a transmission power control unit. The plurality of spatial paths are formed in a one-to-one correspondence with the plurality of antennas,
The mobile station according to claim 7, wherein the transmission power control unit controls the transmission power changing unit to change an uplink transmission power value of at least a part of the plurality of antennas according to the control message. Terminal device. The plurality of antennas are divided into a plurality of sub-array antennas, and the plurality of spatial paths are formed in a one-to-one correspondence with the plurality of sub-array antennas,
8. The transmission power control unit according to claim 7, wherein the transmission power control unit controls the transmission power change unit to change an uplink transmission power value of at least a part of the plurality of sub-array antennas in accordance with the control message. Mobile terminal device. The mobile terminal device according to claim 9, wherein the transmission power changing unit uniformly changes the transmission power value of each of a plurality of antennas constituting a sub-array antenna whose transmission power value is to be changed. The mobile terminal device according to claim 9, wherein the transmission power changing unit changes a transmission power value of a specific antenna among a plurality of antennas constituting a sub-array antenna whose transmission power value is to be changed. The mobile terminal device according to claim 9, wherein the transmission power changing unit changes a beam gain of a radio wave transmitted from a subarray antenna whose transmission power value is to be changed. An uplink transmission power control method in a radio base station capable of spatial multiplexing connection with a mobile terminal device having a plurality of antennas,
Performing signal processing to transmit and receive signals by forming a plurality of spatial paths between the plurality of antennas of the mobile terminal device;
Measuring the received power level of a signal received from the mobile terminal device via the plurality of spatial paths,
A control message for controlling an uplink transmission power value from the mobile terminal device of at least a part of the plurality of spatial paths so that the measured reception power levels of the plurality of spatial paths become uniform. Generating
Transmitting the generated control message via at least a part of the plurality of spatial paths. An uplink transmission power control method in a mobile terminal device having a plurality of antennas,
Performing signal processing for transmitting and receiving signals with the plurality of antennas;
When transmitting and receiving signals by forming a plurality of spatial paths between a radio base apparatus capable of spatial multiplexing and the plurality of antennas, an uplink transmission power value of the mobile terminal apparatus received from the radio base apparatus. Controlling the uplink transmission power values of the at least some of the plurality of spatial paths in response to a control message controlling the transmission power control. A mobile terminal device having a plurality of antennas, and a transmission power control method in a mobile communication system including a wireless base device capable of spatial multiple access,
Forming a plurality of spatial paths between the mobile terminal device and the wireless base device to transmit and receive signals,
Measuring the received power level of the signal received at the wireless base device through the plurality of spatial paths from the mobile terminal device,
A control message for controlling an uplink transmission power value from the mobile terminal device of at least a part of the plurality of spatial paths so that the measured reception power levels of the plurality of spatial paths become uniform. Generating
Transmitting the generated control message to the mobile terminal via a spatial path of at least a part of the plurality of spatial paths;
An uplink transmission power value of at least a part of the spatial paths of a plurality of spatial paths in response to a control message for controlling an uplink transmission power value of the mobile terminal apparatus received by the mobile terminal apparatus from the radio base apparatus. Controlling the transmission power. Upstream transmission power control program in a radio base station capable of spatial multiplexing connection with a mobile terminal device having a plurality of antennas, the computer,
Performing signal processing to transmit and receive signals by forming a plurality of spatial paths between the plurality of antennas of the mobile terminal device;
Measuring the received power level of a signal received from the mobile terminal device via the plurality of spatial paths,
A control message for controlling an uplink transmission power value from the mobile terminal device of at least a part of the plurality of spatial paths so that the measured reception power levels of the plurality of spatial paths become uniform. Generating
And transmitting the generated control message via at least a part of the plurality of spatial paths. An uplink transmission power control program in a mobile terminal device having a plurality of antennas, wherein the computer has
Performing signal processing for transmitting and receiving signals with the plurality of antennas;
When transmitting and receiving signals by forming a plurality of spatial paths between a wireless base device capable of spatial multiplexing and the plurality of antennas, an uplink transmission power value of the mobile terminal device received from the wireless base device. Controlling the uplink transmission power value of at least some of the spatial paths of a plurality of spatial paths in response to a control message controlling the transmission power control program.

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