WO2006035704A1 - マルチキャリア通信装置及びマルチキャリア通信方法 - Google Patents
マルチキャリア通信装置及びマルチキャリア通信方法 Download PDFInfo
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- WO2006035704A1 WO2006035704A1 PCT/JP2005/017617 JP2005017617W WO2006035704A1 WO 2006035704 A1 WO2006035704 A1 WO 2006035704A1 JP 2005017617 W JP2005017617 W JP 2005017617W WO 2006035704 A1 WO2006035704 A1 WO 2006035704A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2626—Arrangements specific to the transmitter only
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
Definitions
- the present invention relates to a communication apparatus and method for transmitting / receiving a multicarrier signal such as an OFDM (Orthogonal Frequency Division Multiplexing) signal.
- a multicarrier signal such as an OFDM (Orthogonal Frequency Division Multiplexing) signal.
- FIG. 1 shows an outline of a radio communication system using the technique described in Patent Document 1.
- a transmitter and a receiver having a smart antenna together set up a plurality of adjacent subcarriers in an OFDM signal to form one group, and a weight Wr for each subcarrier group.
- Patent Document 1 JP 2002-198878 A
- An object of the present invention is to provide a multicarrier communication apparatus and a multicarrier communication method that improve the reception characteristics of a multicarrier signal while reducing the amount of calculation processing required to calculate a reception weight to be multiplied by the multicarrier signal. It is to be.
- the multicarrier communication apparatus is a multicarrier communication apparatus on the multicarrier signal transmission side, and performs weighting by multiplying a plurality of subcarriers constituting one subcarrier group by the same reception weight.
- a communication device that wirelessly transmits a multicarrier signal to a receiving-side communication device, and generates a transmission weight for each subcarrier based on the reception weight for each subcarrier group and propagation path information for each subcarrier. It adopts a configuration comprising transmission weight generating means, weighting means for multiplying the corresponding transmission carrier by the generated transmission weight and weighting, and transmitting means for wirelessly transmitting the weighted multicarrier signal.
- the multicarrier communication apparatus is a multicarrier communication apparatus on the multicarrier signal reception side, and receives a multicarrier signal weighted by multiplying a transmission weight for each subcarrier. And a weighting unit that weights the received multicarrier signal by multiplying one reception weight for each subcarrier group composed of a plurality of subcarriers.
- the multicarrier communication method includes a propagation path information generation step for generating propagation path information for each subcarrier in the multicarrier signal based on the received multicarrier signal, and the generated subcarriers. Based on the propagation path information for each carrier, a reception weight generation step for generating a reception weight for each subcarrier group composed of a plurality of subcarriers, and a reception weight for each generated subcarrier group are generated. A transmission weight generation step for generating a transmission weight for each subcarrier based on the propagation path information for each subcarrier, and multiplying the corresponding subcarrier by the generated transmission weight.
- a transmission weighting step for weighting the multicarrier signal a transmission step for wirelessly transmitting the weighted multicarrier signal, a reception step for receiving the wirelessly transmitted multicarrier signal, and a received multicarrier signal.
- a reception weighting step in which a plurality of subcarriers constituting one subcarrier group are multiplied by the same reception weight and weighted.
- the receiving levels and phases of a plurality of subcarriers in one subcarrier duplex are uniform. Since the transmission weight multiplied by the signal is adaptively adjusted for each subcarrier according to the propagation path condition for each subcarrier, the multicarrier signal is reduced while reducing the calculation processing amount of the reception weight in the receiving multicarrier communication apparatus. It is possible to improve the reception characteristics.
- FIG. 1 is a conceptual diagram showing a relationship between weights used in a conventional transmission-side multicarrier communication apparatus and weights used in a reception-side multicarrier communication apparatus.
- FIG. 2 is a diagram for explaining the result of multiplying a multicarrier signal by a weight using a conventional multicarrier communication apparatus.
- FIG. 3 is a conceptual diagram showing the relationship between transmission weights and reception weights multiplied by multicarrier signals by the multicarrier communication apparatus according to Embodiment 1
- FIG. 4 is a diagram for explaining the effect of weighting by transmission weights in the first embodiment
- FIG. 5 shows a configuration of a mobile radio communication system in the first embodiment.
- FIG. 6 is a block diagram showing the main configuration of the multicarrier communication apparatus according to Embodiment 1.
- FIG. 7 is a block diagram showing the main configuration of the multicarrier communication apparatus according to Embodiment 1
- FIG. 8 is a flowchart for explaining the operation of the multicarrier communication apparatus in the first embodiment.
- FIG. 9 is a flowchart for explaining the operation of the multicarrier communication apparatus in the first embodiment.
- FIG. 10 is a diagram illustrating a first example in which a subcarrier group is determined based on a correlation value between subcarriers in Embodiment 2.
- FIG. 11 Subcarrier group based on correlation value between subcarriers in embodiment 2.
- FIG. 12 is a block diagram showing a configuration of a transmission weight generation section provided in the multicarrier communication apparatus according to Embodiment 2
- FIG. 13 is a block diagram showing a configuration of a reception weight generation section provided in the multicarrier communication apparatus according to Embodiment 2
- FIG. 14 is a flowchart for explaining the operation of the multicarrier communication apparatus in the second embodiment.
- FIG. 15 is a flowchart for explaining the operation of the multicarrier communication apparatus in the second embodiment.
- the block diagram which shows the structure of the reception weight production
- FIG. 17 is a block diagram showing a configuration of a transmission weight generation section provided in the multicarrier communication apparatus according to Embodiment 3
- FIG. 18 is a block diagram showing the main configuration of the multicarrier communication apparatus according to Embodiment 4.
- FIG. 19 is a block diagram showing the main configuration of the multicarrier communication apparatus according to Embodiment 4. Best form
- FIG. 3 shows a transmission weight Wt ′ x (x is an arbitrary natural number) multiplied by a multicarrier signal by the multicarrier communication apparatus according to Embodiment 1 of the present invention and a reception weight Wt ”y (y is an arbitrary smaller than X).
- Fig. 3 is a conceptual diagram showing the relationship with a natural number.
- the transmission-side multicarrier communication apparatus calculates a transmission weight for each subcarrier and multiplies the corresponding subcarrier.
- the receiving multicarrier communication device multiplies all the subcarriers in one subcarrier group by one reception weight.
- the transmission-side multicarrier communication apparatus takes transmission weights into consideration in the reception status for each subcarrier in the reception-side multicarrier communication apparatus, that is, the propagation path status for each subcarrier.
- a transmission weight to be multiplied for each subcarrier is generated so that the reception level and phase for each subcarrier of the multicarrier signal after multiplication are uniform in the same subcarrier group.
- the transmission weight and the reception weight are coefficients for controlling the amplitude and the phase, and for example, complex coefficients are used.
- the multi-carrier communication devices on the transmission side and the reception side both include a plurality of antennas, and MIMO (Multiple Input Multiple Output) transmission technology is used. Used for high-speed wireless communication.
- MIMO transmission Space Division Multiplexing (SDM) is performed to increase the transmission capacity by transmitting signals with different antenna powers at the same time and at the same frequency.
- SDM Space Division Multiplexing
- the weight used for weighting is generated by matrix operations such as eigenvalue decomposition and inverse matrix operation based on propagation path information that is an estimation result of propagation path conditions.
- the calculation processing amount increases in the order of the square, the third power, or more according to the number of elements of the matrix. Therefore, if MIMO transmission technology is applied to multicarrier communication, the propagation path conditions differ for each subcarrier of the multicarrier signal between the transmitting and receiving antennas, and therefore there are at least as many matrix elements as there are subcarriers. Therefore, the amount of calculation processing required for weight generation becomes enormous.
- the MIMO transmission technology can realize high transmission capacity, it is considered to be used in, for example, multicast communication, and is applied to the downlink from the base station to the mobile station as shown in FIG. It is thought that it is done.
- the arithmetic processing in the receiving-side multi-carrier communication apparatus is generally performed so that even a mobile station with low arithmetic processing capability can perform multi-carrier signal reception processing accurately. It is necessary to take measures to reduce the amount.
- the transmission-side multicarrier communication apparatus is a base station, and the reception-side multicarrier communication apparatus is a mobile station.
- the multicarrier signal is an OF DM signal.
- the transmitting-side multicarrier communication apparatus and the receiving-side multicarrier communication apparatus know in advance the subcarriers that make up the subcarrier group.
- the subcarriers constituting the subcarrier group are fixed, and one subcarrier group is composed of a predetermined number of subcarriers adjacent in frequency.
- MIMO transmission is performed using the TDD (Time Division Duplex) method.
- the total number of subcarriers in the OFDM signal is “N”, the arbitrary subcarrier number is “n”, the total number of subcarrier groups in the OFDM signal is “M”, and the arbitrary subcarrier group number is “m”. ".
- FIG. 6 is a block diagram showing the main configuration of multicarrier communication apparatus 400 according to the present embodiment.
- Multicarrier communication apparatus 400 is a receiving-side multicarrier communication apparatus that is mounted on a mobile station such as a mobile phone.
- the multicarrier communication apparatus 400 includes two antennas 401-1, 401-2, two transmission / reception units 402-1, 402-2, a reception weight generation unit 410, and two reception weighting units 420-1, 420-2.
- a plurality of components having the same function in the multicarrier communication apparatus 400 are denoted by the same reference numerals, and in order to distinguish the components having the same reference numerals from each other, Add a branch number.
- branch numbers may be omitted when a common function or operation is described for a plurality of components having the same reference numerals.
- the reception weight generation unit 410 includes a propagation path information generation unit 411 and M subcarrier duplex reception weight generation units 412-1 to 412 -M.
- FFT Fast Fourier Transform
- the transmission / reception unit 402 receives an OFDM signal that is MIMO-transmitted in the downlink from the multicarrier communication apparatus 500 described later via the antenna 401, and performs predetermined reception processing such as frequency conversion and amplification on the received signal. Then, the received signal is input to the FFT unit 421 and the propagation path information generation unit 411, respectively.
- Propagation path information generation section 411 extracts a pilot signal from the received signal input from transmission / reception section 402, and performs channel estimation for each subcarrier based on the extracted pilot signal. Then, propagation path information for each subcarrier is generated, and the generated propagation path information for each subcarrier is input to the subcarrier group reception weight generation section 412.
- the subcarrier group reception weight generation section 412 is based on the propagation path information for each subcarrier input from the propagation path information generation section 411, and is the subcarrier closest to the center frequency in the subcarrier group in charge. And a reception weight for multiplying all subcarriers in the subcarrier group is generated based on the channel estimation value of the selected subcarrier. Then, subcarrier group reception weight generation section 412 inputs the generated reception weight to corresponding multiplier 422. The manner in which subcarrier group reception weight generation section 412 generates reception weights will be described later.
- the FFT unit 421 converts the received signal input from the transmission / reception unit 402 from a serial signal to a parallel signal, and further performs a fast Fourier transform process to separate the OFDM signal for each subcarrier, and then The normal signal is input to the multiplier 422.
- Multiplier 422 multiplies the parallel signal for each subcarrier input from FFT section 421 by the reception weight input from subcarrier group reception weight generation section 412.
- Multiplier 422-1 inputs the parallel signal multiplied by the reception weight to adder 423 1 and also inputs to adder 423-2 that handles the same subcarrier as adder 423-1. That is, multiplier 422 is a main component of the weighting means in multicarrier communication apparatus 400.
- the adder 423-1 includes a reception signal input from the multiplier 422-1, and a parallel signal input from the multiplier 422-2 that handles the same subcarrier as the multiplier 422-1. And the result of the addition is input to the PZS converter 424-1.
- the adder 42 3-2 is connected to the parallel signal input from the multiplier 422-2 and the parallel signal input from the multiplier 422-1 that handles the same subcarrier as the multiplier 422-2. The signal is added and the result is input to the PZS conversion unit 424-2.
- FIG. 7 is a block diagram showing the main configuration of multicarrier communication apparatus 500 according to the present embodiment.
- Multicarrier communication apparatus 500 is a transmission-side multicarrier communication apparatus, for example, mounted on a base station in a mobile radio communication system.
- Multi-carrier communication apparatus 500 includes two antennas 501-1 and 501-2, two transmission / reception units 5021, 502-2, a transmission weight generation unit 510, and two transmission weighting units 520-1 and 520-2. To do.
- a plurality of components having the same function in the multicarrier communication apparatus 500 are denoted by the same reference symbols, and in addition, in order to distinguish the components having the same functions from each other, a branch is added after the reference symbols. Give it a number.
- the transmission weight generation unit 510 includes a propagation path information generation unit 511, M subcarrier group reception weight generation units 512-1 to 512-M and N subcarrier transmission weight generation units 513-1 to 513-. N.
- the reception weighting units 520-1 and 520-2 are serial Z parallel (SZP) conversion units 521-1, 521-2, and N multipliers 522-1-1 to 522-1 N, 522, respectively. — 2— 1 to 52 2— 2— N, N Calorie 523— 1— 1 to 523— 1— N, 523— 2— 1 to 523— 2— N and Inverse Fast Fourier Transform (Inverse Fast Fourier Transform) Transform: IFFT) sections 524-1 and 524-2.
- SZP serial Z parallel
- Transmission / reception section 502 receives an OFDM signal MIMO-transmitted from multicarrier communication apparatus 400 in the uplink via antenna 501 and performs predetermined reception processing such as frequency conversion and amplification on the received signal.
- the received signal is input to propagation path information generation section 511. Further, the transmission / reception unit 502 performs predetermined transmission processing on a transmission signal (OF DM signal) input from an IFFT unit 524 described later, and then transmits the OFDM signal to the multicarrier communication apparatus via the antenna 501 in the downlink. 400 MIMO transmission.
- OFDM signal transmission signal
- IFFT unit 524 described later
- Propagation path information generation section 511 extracts a pilot signal from the received signal input from transmission / reception section 502, and performs channel estimation for each subcarrier based on the extracted pilot signal, thereby performing channel estimation for each subcarrier. Propagation path information is generated, and the generated propagation path information for each subcarrier is input to subcarrier group reception weight generation section 512 and subcarrier transmission weight generation section 513, respectively.
- Subcarrier group reception weight generation section 512 is a subcarrier group reception way.
- the subcarrier that functions in the same manner as the channel generation unit 412 is based on the propagation path information for each subcarrier input from the propagation path information generation unit 511.
- the reception weight of the subcarrier group is generated.
- subcarrier group reception weight generation section 512 inputs the generated reception weight to subcarrier transmission weight generation section 513.
- Subcarrier transmission weight generation section 513 receives propagation path information for each subcarrier input from propagation path information generation section 511, and for each subcarrier group input from subcarrier group reception weight generation section 512. A transmission weight for each subcarrier is generated based on the reception weight. Subcarrier transmission weight generation section 513 inputs the generated transmission weight for each subcarrier to corresponding multiplier 522. The manner in which subcarrier transmission weight generation section 513 generates transmission weights will be described later.
- the SZP conversion unit 521 separates transmission data, which is also input with a control unit equal force (not shown), from a serial signal into a parallel signal, thereby separating the parallel signal into a signal for each subcarrier. To enter.
- Multiplier 522 multiplies the parallel signal input from SZP conversion section 521 by the transmission weight input from subcarrier transmission weight generation section 513.
- Multiplier 522-1 inputs the parallel signal multiplied by the transmission weight to adder 523-1 and also inputs to adder 523-2 that handles the same subcarrier as adder 523-1. To do. That is, multiplier 522 is a main component of weighting means in multicarrier communication apparatus 500.
- the adder 523-1 includes a parallel signal input from the multiplier 522-1 and a parallel signal input from the multiplier 522-2 that handles the same subcarrier as the multiplier 522-1. And the result of the addition is input to IFFT section 524-1.
- the adder 52 3-2 includes a parallel signal input from the multiplier 522-2 and a parallel signal input from the multiplier 522-1, which handles the same subcarrier as the multiplier 522-2. Add the signal and input the result to IFFT section 524-2.
- IFFT section 524 performs inverse fast Fourier transform on the addition result input from adder 523, and An OFDM signal is generated by converting the converted signal into a serial signal from the parallel signal, and the generated OFDM signal is input to the transmission / reception section 502.
- propagation path information generation section 411 extracts a pilot signal from the downlink received signal, and performs channel estimation for each subcarrier using the pilot signal. Generates propagation path information for each subcarrier indicating the propagation path condition for each subcarrier in the downlink.
- subcarrier group reception weight generation section 412 generates a reception weight for each subcarrier group based on the propagation path information for each subcarrier generated in step ST610.
- the reception weight Wrx is expressed by Equation 1 using the propagation path information H of subcarrier p as the Zero Forcing weight. Calculated.
- Wrx m H / (Formula 1)
- the subscript “+” in Formula 1 indicates Moore-Penrose-Generalized Inverse Matrix Operation.
- step ST630 the reception weight for each subcarrier group generated in the multiplier 422 power step ST620 is multiplied by all the subcarriers in the subcarrier group, and the received signal is weighted.
- step ST640 Karo arithmetic 423 and PZS converter 424 force step ST6
- Received data is generated by adding the received signals weighted at 30 and performing FFT processing.
- propagation path information generation section 511 extracts a pilot signal from an uplink received signal and performs channel estimation based on the pilot signal, thereby performing uplink propagation. Propagation path information for each subcarrier indicating the path status is generated.
- step ST720 subcarrier group reception weight generation section 512 Based on the propagation path information for each subcarrier generated in step ST710, the reception weight for each subcarrier group is generated using, for example, Equation 1 in the same manner as in step ST620.
- subcarrier group reception weight generation section 512 is identical to the reception weight generated by subcarrier group reception weight generation section 412 in order to improve the OFDM signal reception characteristics in multicarrier communication apparatus 400.
- the subcarrier group reception weight generation unit 512 since the OFDM signal is transmitted / received by the TDD scheme, the subcarrier group reception weight generation unit 512 generates the subcarrier generated based on the pilot signal in the uplink.
- Each channel information can be used as channel information for each subcarrier generated based on a pilot signal in the downlink. This is because the slots used by the downlink and uplink have a slight time difference and the same frequency band, so that reversibility is recognized between the uplink and downlink.
- subcarrier transmission weight generation section 513 receives the propagation path information for each subcarrier in the uplink generated in step ST710 and the reception for each subcarrier group generated in step ST720. Based on the weight, a transmission weight is generated for each subcarrier.
- the transmission weight Wtx of subcarrier n in subcarrier group m is the reception weight Wrx according to Equation 1 and the propagation path information H of subcarrier n.
- step ST740 the multiplier 522 power multiplies the transmission weight for each subcarrier generated in step ST730 by multiplying the corresponding subcarrier (parallel signal), and weights the parallel signal.
- step ST750 the adder 523 and the IFFT unit 524 force add the weighted parallel signals in step ST740, and further perform IFFT processing to obtain a transmission signal (O
- a multicarrier communication apparatus for transmitting an OFDM signal. 500 Forces Understand the propagation path conditions (downlink propagation path conditions) for each subcarrier in the multicarrier communication device 400 that receives the OFDM signal, and receive levels of all subcarriers in the subcarrier group of the OFDM signal. Since the transmission weight multiplied by each subcarrier is adjusted so that the phase and the phase are uniform, the reception characteristics of this OFDM signal are improved while reducing the amount of reception weight generation processing in the multicarrier communication device 400 Can be made.
- the reception weight generation calculation processing amount in multicarrier communication apparatus 400 is effectively reduced, so that the circuit scale is reduced and the power consumption is reduced. be able to.
- the multi-carrier communication device 400 is mounted on a mobile station such as a mobile phone, the product value is significantly improved by reducing the circuit scale and power consumption.
- multicarrier communication apparatus 500 uniquely generates a reception weight necessary for generating a transmission weight based on a pilot signal transmitted from multicarrier communication apparatus 400.
- the reception weight itself transmitted from multicarrier communication apparatus 400 through a feedback line or the like since it is not necessary to have the reception weight itself transmitted from multicarrier communication apparatus 400 through a feedback line or the like, the data transmission rate on the uplink can be easily increased.
- multicarrier communication apparatuses 400 and 500 may be modified or applied as follows.
- multicarrier communication apparatus 500 independently generates a reception weight necessary for generating a transmission weight.
- the present invention is not limited to this case, for example, multi The reception weight generated by the carrier communication device 400 may be notified to the multicarrier communication device 500 through a feedback line or the like. In this way, since subcarrier group reception weight generating section 512 can be removed from multicarrier communication apparatus 500, the configuration of multicarrier communication apparatus 500 can be simplified.
- the present invention is limited to this case.
- the multicarrier communication device 500 transmits transmission weight to the propagation path information for each subcarrier generated by the propagation path information generation unit 511.
- the transmission path information for each subcarrier may be transmitted to the multicarrier communication apparatus 400 by MIMO transmission.
- multicarrier communication apparatus 400 can receive the reception weight based on the propagation path information for each subcarrier generated by propagation path information generation section 511 even if the pilot signal is not transmitted from multicarrier communication apparatus 500. Can be generated. Therefore, in this case, it is not necessary to transmit a pilot signal from multicarrier communication apparatus 500 to multicarrier communication apparatus 400, so that the transmission capacity in the downlink can be further increased.
- subcarrier group reception weight generation section 412 or subcarrier group reception weight generation section 512 generates a ZeroForcing weight as a reception weight
- the present invention is limited to this case.
- the subcarrier group reception weight generation unit 412 or the subcarrier group reception weight generation unit 512 may generate MMSE (least square error) weights or eigenvectors used for eigenbeam transmission as reception weights. Oh ,.
- subcarrier group reception weight generation section 412 or subcarrier group reception weight generation section 512 is based on the channel estimation value of the subcarrier closest to the center frequency in the subcarrier group.
- the reception weight is generated has been described, the present invention is not limited to this case.
- the subcarrier group reception weight generation unit 412 or the subcarrier group reception weight generation unit 512 has the reception power in the subcarrier group.
- the reception weight may be generated. In this way, it is possible to effectively increase the detection accuracy of the propagation path information for each subcarrier, and as a result, it is possible to effectively improve the OFDM signal reception characteristics in the multicarrier communication apparatus 400. .
- the subcarrier group reception weight generation section 412 or the subcarrier duplex reception weight generation section 512 performs a check for all subcarriers in the subcarrier group.
- the reception weight for each subcarrier may be generated based on the average value of the channel estimation values. In this way, even when the channel estimation value for each subcarrier in the subcarrier group is biased, the reception characteristics of the OFDM signal in multicarrier communication apparatus 400 can be stabilized.
- subcarrier group reception weight generation section 412 or subcarrier group reception weight generation section 512 uses subcarrier instead of the average value of channel estimation values of all subcarriers in the subcarrier group.
- the average value of the channel estimation values of the highest frequency subcarrier and the lowest frequency subcarrier in the group may be used. In this way, it is possible to stabilize the reception characteristics of the OFDM signal in the multicarrier communication apparatus 400 in view of the fact that the fluctuations in the propagation conditions of the subcarriers at both ends of the subcarrier group are probabilistically uniform. It is considered possible.
- subcarrier group reception weight generation section 412 or subcarrier group reception weight generation section 512 uses subcarriers instead of the average value of channel estimation values of all subcarriers in the subcarrier group. Let's use the average value of the channel estimates of the subcarriers at predetermined intervals in the group. In this way, subcarrier group reception weight generation section 412 or subcarrier group reception weight generation section 512 can effectively reduce the amount of calculation processing required to generate reception weights for each subcarrier group. .
- the present invention is not limited to this case.
- amplitude information or phase information is used.
- the expressed real number coefficient may be used. In this way, if the fluctuation force in the subcarrier group, either the amplitude fluctuation or the phase fluctuation, is more dominant, a transmission weight is generated only for the dominant fluctuation, The same effect can be obtained by multiplying the transmission weight generated on the transmission side.
- the multi-carrier communication apparatus 400 and the multi-carrier communication apparatus 500 perform the MIMO transmission of the OFDM signal using the TDD scheme!
- multi-carrier communication device 400 and multi-carrier communication device 500 are not limited to the FDD (Frequency Division Duplex) method.
- the OFDM signal may be MIMO-transmitted using the equation.
- the reception weight generation unit 512 cannot generate a reception weight based on the propagation path information for each subcarrier generated by the propagation path information generation unit 511.
- the reception weight generated by the subcarrier group reception weight generation unit 412 of the multicarrier communication apparatus 400 is transmitted to the multicarrier communication apparatus 500 using a feedback circuit or the like. There is a need to.
- information transmitted to multicarrier communication apparatus 500 using the feed knock line is set for each subcarrier generated by propagation path information generation unit 411.
- the propagation path information may be transmitted.
- the power described for the case where multicarrier communication apparatus 500 that transmits an OFDM signal is a base station, and multicarrier communication apparatus 400 that receives the OFDM signal is a mobile station.
- the multicarrier communication apparatus 500 that transmits an OFDM signal may be a mobile station, and the multicarrier communication apparatus 400 that receives the OFDM signal may be a base station.
- the correlation of propagation path conditions between subcarriers is calculated in Embodiment 1, and a subcarrier group is determined based on the correlation value. That is, in Embodiment 1, the power described in the case where the subcarriers constituting the subcarrier group are fixed in advance. In this embodiment, the subcarriers constituting the subcarrier group have a correlation value between the subcarriers. It changes adaptively accordingly. In other words, in the first embodiment, when the propagation path condition greatly fluctuates in time within the band of one subcarrier group, the subcarriers are fixed, so the subcarriers constituting the group are fixed. There is a risk that transmission weights that do not reflect actual propagation path conditions will be multiplied.
- a correlation between subcarriers is calculated, and subcarriers having a high correlation value are grouped to form a channel state in the subcarrier group. Even if the situation changes significantly over time, it prevents degradation of the reception characteristics of OFDM signals in the receiving multicarrier communication device.
- FIG. 10 shows a first example in which a subcarrier group is determined based on a correlation value between subcarriers.
- an arbitrary subcarrier is defined as a reference subcarrier, and a correlation value between this reference subcarrier and another subcarrier is calculated. The method for calculating the correlation value between subcarriers will be described later.
- the calculated correlation value is compared with a predetermined threshold value, for example, 0.7, and subcarriers having a correlation value of 0.7 or more are collectively determined as subcarrier group 1. Therefore, in the first example shown in FIG. 10, the number of subcarriers constituting a subcarrier group varies according to the distribution of correlation values between subcarriers, that is, according to the propagation path condition for each subcarrier. Become.
- FIG. 11 shows a second example in which a subcarrier group is determined based on a correlation value between subcarriers.
- all correlation values between subcarriers existing in a predetermined bandwidth are calculated, and the calculated correlation values between subcarriers are formed into a matrix, and the subcarriers are calculated based on the matrix.
- After detecting a band with a high correlation value subcarriers in a band with a high correlation value between the subcarriers are grouped together.
- the total number of subcarrier groups is determined in advance, and the number of subcarriers constituting one subcarrier group is changed.
- FIG. 12 is a block diagram showing a configuration of transmission weight generation section 1010 provided in the multicarrier communication apparatus according to the present embodiment.
- Transmission weight generation section 1010 is a component provided in place of transmission weight generation section 510 in multicarrier communication apparatus 500.
- the transmission weight generation unit 1010 further includes an intersubcarrier correlation calculation unit 1011 and a subcarrier group determination unit 1012 in the transmission weight generation unit 510. Therefore, since transmission weight generation section 1010 includes all the constituent elements included in transmission weight generation section 510, in this embodiment, description of such identical components is omitted to avoid duplication. .
- Inter-subcarrier correlation calculation section 1011 performs channel estimation for all subcarriers in the OFDM signal based on the uplink pilot signal input from transmission / reception section 502, and uses the channel estimation value to perform sub-estimation. A correlation value between carriers is calculated. And The inter-subcarrier correlation calculation unit 1011 inputs the calculated correlation value between the subcarriers to the subcarrier group determination unit 1012.
- the subcarrier group determination unit 1012 is based on the correlation value between the subcarriers input from the intersubcarrier correlation calculation unit 1011, or the second example shown in FIG. The subcarrier group is determined as in the example. Then, subcarrier group determination section 1012 notifies subcarrier group reception weight generation section 512 of information on the determined subcarrier group.
- FIG. 13 is a block diagram showing a configuration of reception weight generation section 1110 provided in the multicarrier communication apparatus according to the present embodiment.
- Reception weight generation unit 1110 is a component provided in place of reception weight generation unit 410 in multi-carrier communication apparatus 400.
- reception weight generation section 1110 further includes intersubcarrier correlation calculation section 1111 and subcarrier group determination section 1112 in reception weight generation section 410. Accordingly, the reception weight generation unit 1110 includes all the components included in the reception weight generation unit 410. Therefore, in the present embodiment, description of such identical components is omitted to avoid duplication. .
- Inter-subcarrier correlation calculation section 1111 performs channel estimation for all subcarriers in the OFDM signal based on the downlink pilot signal input from transmission / reception section 402, and uses the channel estimation value to perform sub-estimation. A correlation value between carriers is calculated. Then, subcarrier correlation calculation section 1111 inputs the calculated correlation value between subcarriers to subcarrier group determination section 1112.
- subcarrier group determination section 1112 Based on the correlation value between subcarriers input from intersubcarrier correlation calculation section 1111, subcarrier group determination section 1112 receives the first example shown in FIG. 10 or the second shown in FIG. The subcarrier group is determined as in the example. Then, the subcarrier group determination unit 1112 notifies the subcarrier group reception weight generation unit 412 of the information regarding the determined subcarrier group.
- step ST1213, step ST1215, and step ST1217 are executed between step ST610 and step ST620 in FIG. 8 according to the subcarrier group determination. In the following, only the steps related to the determination of the subcarrier group will be described in order to avoid duplication.
- reception weight generation section 1110 is a method in which multicarrier communication apparatus 400 uniquely determines a subcarrier group based on a pilot signal in the downlink, or multicarrier communication.
- the system power to know and use the determined subcarrier group of the device 500 is determined.
- step ST1213 when subcarrier correlation calculation section 1111 determines that multicarrier communication apparatus 400 uniquely determines the subcarrier group, step ST1215 is followed by step ST1215.
- step ST1213 is followed by step. ST1217 is executed.
- inter-subcarrier correlation calculation section 1111 calculates a correlation value between subcarriers based on the propagation path information for each subcarrier in the downlink generated in step ST610.
- the propagation path information at the j-th antenna in subcarrier n is expressed as h
- the correlation calculation unit 1111 between subcarriers calculates the correlation value between subcarriers calculated in the same manner for other antennas, for example, by averaging the subcarriers.
- step ST1215 the subcarrier Group determining section 1112 determines a subcarrier group based on the correlation value between subcarriers calculated by intersubcarrier correlation calculating section 1111.
- inter-subcarrier correlation calculation section 1111 obtains information on the subcarrier group determined by multicarrier communication apparatus 500 transmitted via the feedback line or the like. Then, the obtained subcarrier group information is notified to the subcarrier group reception weight generation unit 412 via the subcarrier group determination unit 1112.
- step ST1313, step ST1315, and step ST1317 are executed between step ST710 and step ST720 in FIG. 9 according to the subcarrier group determination.
- step ST1315, and step ST1317 are executed between step ST710 and step ST720 in FIG. 9 according to the subcarrier group determination.
- steps related to the determination of the subcarrier group will be described in order to avoid duplication.
- inter-subcarrier correlation calculation section 1011 uses the scheme power for multicarrier communication apparatus 500 to uniquely determine the subcarrier group based on the pilot signal in the uplink, or multi-carrier The system power to know and use the subcarrier group determined by the carrier communication device 400 is determined. Then, in step ST1 313, when subcarrier correlation calculation section 1011 determines that multicarrier communication apparatus 400 is a method of uniquely determining subcarrier groups, step ST1313 is followed by step 3 1315 is executed, and on the other hand, if it is determined that the subcarrier group determined by the multicarrier communication apparatus 400 is obtained by using the subcarrier correlation calculation unit 10 11 force, the process continues to step ST1313. Step ST1317 is then executed.
- Step ST1315 the inter-subcarrier correlation calculating section 1011 performs the same processing as in Step ST1215 on the basis of the propagation path information for each uplink subcarrier generated in Step ST710.
- the correlation value p is calculated.
- the subcarrier group determination unit 1012 determines the subcarrier group based on the correlation value p between subcarriers calculated by the intersubcarrier correlation calculation unit 1011.
- Step ST1317 the inter-subcarrier correlation calculation section 1011 performs feedback.
- Information on the subcarrier group determined by the multicarrier communication apparatus 400 transmitted over the network, etc., is acquired, and the acquired subcarrier group information is transmitted to the subcarrier via the subcarrier group determination unit 1012. Notify group reception wait generator 512.
- the subcarrier force constituting the subcarrier group is adaptively determined according to the correlation value between subcarriers calculated based on the channel estimation value for each subcarrier. Therefore, subcarriers having a high correlation value between the subcarriers can be grouped. As a result, even if the time fluctuation of the propagation path condition for each subcarrier is large, the OFDM signal in the multicarrier communication apparatus 400 is Can effectively improve the reception characteristics.
- multicarrier communication apparatuses 400 and 500 may be modified or applied as follows.
- the power described for the case where subcarriers constituting a subcarrier group are adaptively determined according to the correlation value between subcarriers is not limited to this case.
- the number of subcarriers constituting one subcarrier group may be determined in advance, and the total number of subcarrier groups may be adaptively changed according to the correlation value between the subcarriers.
- the number of subcarriers having a high correlation in the assumed environment is predicted and determined. The method of doing is mentioned.
- the number of subcarriers constituting one subcarrier group may be different when transmitting an OFDM signal from a single antenna and when transmitting an OFDM signal from a plurality of antennas. Specifically, the number of subcarriers when transmitting with multiple antenna power is reduced compared to the number of subcarriers when transmitting with single antenna power. This is because when signals are transmitted from multiple antennas, the signals transmitted from each antenna are subjected to frequency selective fading independently and are combined on the receiving side. This is because the number of highly correlated subcarriers is reduced.
- a case has been described in which subcarriers having a high correlation value between subcarriers are grouped among a plurality of adjacent subcarriers, but the present invention is limited to this case.
- a correlation value between non-adjacent subcarriers may also be calculated, and a predetermined number of subcarriers with high or low correlation values between the subcarriers may be grouped in order.
- delay dispersion is calculated for the received OFDM signal in Embodiment 2, and a subcarrier group is determined based on the calculated delay dispersion.
- FIG. 16 is a block diagram showing a configuration of reception weight generation section 1410 provided in the multicarrier communication apparatus according to the present embodiment.
- Reception weight generation section 1410 is a component provided in place of reception weight generation section 410 in multi-carrier communication apparatus 400.
- Reception weight generation section 1410 further includes delay dispersion determination section 1411 and subcarrier group determination section 1412 in reception weight generation section 410. Therefore, the reception weight generation unit 1410 includes all the components included in the reception weight generation unit 410. Therefore, in the present embodiment, description of such identical components is omitted to avoid duplication. .
- delay dispersion determination section 1411 Based on the downlink pilot signal input from transmission / reception section 402, delay dispersion determination section 1411 generates, for example, a delay profile as propagation path information for each subcarrier, and generates the generated delay profile. Based on this, delay dispersion is calculated. Then, the delay dispersion determination unit 1411 inputs the calculated delay dispersion to the subcarrier group determination unit 1412.
- Subcarrier group determining section 1412 determines a subcarrier group based on the delay dispersion input from delay dispersion determining section 1411.
- the delay dispersion is large, the propagation path condition fluctuates greatly within the band of the OFDM signal due to the influence of frequency selective fading due to the delayed wave.
- the number of carriers is generally small.
- subcarrier group determining section 1412 reduces the number of subcarriers to be grouped, and on the other hand, when the delay dispersion is small, In this case, the subcarrier group is determined by increasing the number of subcarriers to be grouped. Then, the subcarrier group determination unit 1412 notifies the subcarrier group reception weight generation unit 412 of the information regarding the determined subcarrier group.
- FIG. 17 is a block diagram showing a configuration of transmission weight generation section 1510 provided in the multicarrier communication apparatus according to the present embodiment.
- Transmission weight generation section 1510 is a component provided in place of transmission weight generation section 510 in multicarrier communication apparatus 500.
- the transmission weight generation unit 1510 further includes a delay dispersion determination unit 1511 and a subcarrier group determination unit 1512 in the transmission weight generation unit 510. Therefore, since transmission weight generation section 1510 includes all the components included in transmission weight generation section 510, in this embodiment, description of such identical components is omitted to avoid duplication. .
- Delay dispersion determining section 1511 generates, for example, a delay profile as propagation path information for each subcarrier based on the uplink pilot signal input from transmitting / receiving section 502, and generates the generated delay profile. Based on this, delay dispersion is calculated. Delay dispersion determination section 1511 inputs the calculated delay dispersion to subcarrier group determination section 1512.
- Subcarrier group determining section 1512 determines a subcarrier group based on the delay dispersion input from delay dispersion determining section 1511. Then, subcarrier group determination section 1512 notifies subcarrier group reception weight generation section 512 of information about the determined subcarrier group.
- reception weight generation section 1410 or transmission weight generation section 1510 calculates the delay dispersion for the downlink or the uplink, and sub-routines according to the calculated delay dispersion. Since the number of subcarriers constituting the carrier group is adjusted, it is possible to adaptively cope with the frequency selective fading situation.
- reception weight generation section 1410 and transmission weight generation section 1510 are not limited to this case, and the delay dispersion determination unit in either the reception weight generation unit 1410 or the transmission weight generation unit 1510 delays the delay distribution. And the calculated delay dispersion may be transmitted to the other using the feedback line. As a result, the number of subcarriers can be adjusted in accordance with the delay dispersion without calculating the delay dispersion in both transmission and reception.
- the delay dispersion calculation method in the delay dispersion determination unit includes a calculation method using a plurality of delay profiles and a calculation method using a specific delay profile. For example, as a method of calculating using a plurality of delay profiles, the delay dispersion for each of the plurality of delay profile forces is calculated, and the average value of the delay dispersion is calculated to obtain the calculation result in the delay dispersion determination unit. can do. In this case, the frequency selective fading, which varies from antenna to antenna, can be handled on an average basis for each fading situation. In addition, the median or dispersion of multiple delay dispersions can be used.
- the delay dispersion of each of a plurality of delay profile forces can be calculated and the maximum value among them can be detected to obtain a calculation result in the delay dispersion determination unit.
- each of multicarrier communication apparatus 400 and multicarrier communication apparatus 500 includes one antenna, and transmits and receives OFD M signals. That is, in the present embodiment, the case will be described where multicarrier communication apparatus 400 and multicarrier communication apparatus 500 do not perform MIMO transmission.
- FIG. 18 is a block diagram showing the main configuration of multicarrier communication apparatus 1600 according to the present embodiment.
- Multi-carrier communication device 1600 is obtained by reducing one antenna 401 from multi-carrier communication device 400, and further reducing transmission / reception unit 402 and reception weighting unit 1620 one by one in accordance with the reduction of antenna 401. is there. Further, the reception weighting unit 1620 is obtained by removing the adder 423 in the reception weighting unit 420 that becomes unnecessary in terms of function as the number of antennas 401 is reduced. Therefore, the multi-carrier communication device 160 Since all the components in 0 are the same as the components in multicarrier communication apparatus 400, in this embodiment, description of the components in multicarrier communication apparatus 1600 is omitted to avoid duplication.
- FIG. 19 is a block diagram showing the main configuration of multicarrier communication apparatus 1700 according to the present embodiment.
- the multi-carrier communication device 1700 is obtained by reducing one antenna 501 from the multi-carrier communication device 500, and further reducing the transmission / reception unit 502 and the transmission weighting unit 1720 one by one in accordance with the reduction of the antenna 501. is there. Further, the transmission weighting unit 1720 is obtained by removing the adder 523 in the transmission weighting unit 520 that becomes functionally unnecessary as the number of the antennas 501 is reduced. Therefore, since all the components in multicarrier communication apparatus 1700 are the same as the components in multicarrier communication apparatus 500, in this embodiment, in order to avoid duplication, description of the components in multicarrier communication apparatus 1700 will be given. Is omitted.
- multicarrier communication apparatus 1700 can calculate transmission weight Wtx by the following “Equation 4”.
- the OFDM signal may be transmitted / received using, that is, in the case of transmission diversity or reception diversity. Further, in this case, by performing transmission diversity or reception diversity for each subcarrier group, the effects of the present embodiment can be obtained when diversity is applied.
- Each functional block used in the description of each of the above embodiments is typically realized as an LSI which is an integrated circuit. These may be individually integrated into one chip, or part or all of them. One chip may be added to include
- IC integrated circuit
- system LSI system LSI
- super LSI non-linear LSI depending on the difference in the power integration of LSI.
- the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. It is also possible to use a field programmable gate array (FPGA) that can be programmed after LSI manufacture and a reconfigurable processor that can reconfigure the connection and settings of circuit cells inside the LSI.
- FPGA field programmable gate array
- the multicarrier communication apparatus and multicarrier communication method according to the present invention improve the reception characteristics of the multicarrier signal while reducing the amount of calculation processing required to calculate the reception weight multiplied by the multicarrier signal. It is effective and is useful for mobile high-speed wireless communication systems that transmit OFDM signals using MIMO.
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Abstract
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MX2007003469A MX2007003469A (es) | 2004-09-28 | 2005-09-26 | Aparato de comunicacion multiportador y metodo de comunicacion multiportador. |
EP05786016A EP1783940A1 (en) | 2004-09-28 | 2005-09-26 | Multicarrier communication apparatus and multicarrier communication method |
US11/576,039 US8064503B2 (en) | 2004-09-28 | 2005-09-26 | Multicarrier communication apparatus and multicarrier communication method |
JP2006537714A JP4597996B2 (ja) | 2004-09-28 | 2005-09-26 | マルチキャリア通信装置及びマルチキャリア通信方法 |
BRPI0516148-7A BRPI0516148A (pt) | 2004-09-28 | 2005-09-26 | aparelho de comunicação de multiportadora e método de comunicação de multiportadora |
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- 2005-09-26 JP JP2006537714A patent/JP4597996B2/ja not_active Expired - Fee Related
- 2005-09-26 RU RU2007111320/09A patent/RU2007111320A/ru not_active Application Discontinuation
- 2005-09-26 CN CNA200580031291XA patent/CN101023612A/zh active Pending
- 2005-09-26 WO PCT/JP2005/017617 patent/WO2006035704A1/ja active Application Filing
- 2005-09-26 MX MX2007003469A patent/MX2007003469A/es active IP Right Grant
- 2005-09-26 EP EP05786016A patent/EP1783940A1/en not_active Withdrawn
- 2005-09-26 KR KR1020077006573A patent/KR20070072862A/ko not_active Application Discontinuation
- 2005-09-26 US US11/576,039 patent/US8064503B2/en active Active
- 2005-09-26 BR BRPI0516148-7A patent/BRPI0516148A/pt not_active IP Right Cessation
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JP2003087070A (ja) * | 2001-09-06 | 2003-03-20 | Ntt Docomo Inc | 送信機および受信機 |
JP2004260322A (ja) * | 2003-02-24 | 2004-09-16 | Mitsubishi Electric Corp | マルチキャリア無線通信システム、送信装置および受信装置 |
JP2005252653A (ja) * | 2004-03-04 | 2005-09-15 | Hokkaido Univ | 周波数オフセット推定方法および装置ならびにそれを利用した受信装置 |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2007139237A1 (en) * | 2006-06-01 | 2007-12-06 | Kabushiki Kaisha Toshiba | Wireless communication apparatus |
EP1863243A1 (en) | 2006-06-01 | 2007-12-05 | Kabushiki Kaisha Toshiba | Wireless communication apparatus |
KR101285379B1 (ko) * | 2006-06-16 | 2013-07-10 | 엘지전자 주식회사 | 상향 링크에서의 부 반송파 배치 방법 및 이를 구현하는송신 장치 |
US8305942B2 (en) | 2007-06-08 | 2012-11-06 | Fujitsu Limited | Estimation of Eigen coherence bandwidth |
JP2008306715A (ja) * | 2007-06-08 | 2008-12-18 | Fujitsu Ltd | 固有コヒーレンス帯域幅の推定 |
WO2009041069A1 (ja) * | 2007-09-28 | 2009-04-02 | Panasonic Corporation | 基地局装置、移動局装置、通信システム、チャネル推定方法、送信アンテナ検出方法及びプログラム |
JP2009182578A (ja) * | 2008-01-30 | 2009-08-13 | Fujitsu Ltd | Mimo−ofdm受信装置およびmimo−ofdm通信システム |
JP2009224936A (ja) * | 2008-03-14 | 2009-10-01 | Kyocera Corp | 無線装置 |
WO2010035809A1 (ja) * | 2008-09-26 | 2010-04-01 | 京セラ株式会社 | 無線通信装置及び無線通信方法 |
JP2010081396A (ja) * | 2008-09-26 | 2010-04-08 | Kyocera Corp | 無線通信装置及び無線通信方法 |
US8855235B2 (en) | 2009-06-03 | 2014-10-07 | Fujitsu Semiconductor Limited | Circuit transmission apparatus and transmission method |
JP2012039576A (ja) * | 2010-08-11 | 2012-02-23 | Kyocera Corp | 通信装置及び通信方法 |
JP2012060543A (ja) * | 2010-09-10 | 2012-03-22 | Toshiba Corp | 無線通信装置 |
WO2012114413A1 (ja) * | 2011-02-24 | 2012-08-30 | 三洋電機株式会社 | 受信装置 |
WO2012161284A1 (ja) * | 2011-05-25 | 2012-11-29 | 京セラ株式会社 | 無線通信装置及び通信制御方法 |
JP2012248968A (ja) * | 2011-05-25 | 2012-12-13 | Kyocera Corp | 無線通信装置及び通信制御方法 |
Also Published As
Publication number | Publication date |
---|---|
EP1783940A1 (en) | 2007-05-09 |
BRPI0516148A (pt) | 2008-08-26 |
RU2007111320A (ru) | 2008-10-10 |
JPWO2006035704A1 (ja) | 2008-05-15 |
MX2007003469A (es) | 2007-05-18 |
US20070263736A1 (en) | 2007-11-15 |
US8064503B2 (en) | 2011-11-22 |
CN101023612A (zh) | 2007-08-22 |
KR20070072862A (ko) | 2007-07-06 |
JP4597996B2 (ja) | 2010-12-15 |
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