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WO2013031538A1 - Dispositif de détermination de schéma de transmission, dispositif formant station de base, processeur, procédé de détermination de schéma de transmission, programme de détermination de schéma de transmission, et dispositif de transmission - Google Patents

Dispositif de détermination de schéma de transmission, dispositif formant station de base, processeur, procédé de détermination de schéma de transmission, programme de détermination de schéma de transmission, et dispositif de transmission Download PDF

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Publication number
WO2013031538A1
WO2013031538A1 PCT/JP2012/070742 JP2012070742W WO2013031538A1 WO 2013031538 A1 WO2013031538 A1 WO 2013031538A1 JP 2012070742 W JP2012070742 W JP 2012070742W WO 2013031538 A1 WO2013031538 A1 WO 2013031538A1
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WIPO (PCT)
Prior art keywords
transmission
mcs
unit
station apparatus
equalization
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Ceased
Application number
PCT/JP2012/070742
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English (en)
Japanese (ja)
Inventor
淳悟 後藤
高橋　宏樹
中村　理
一成 横枕
泰弘 浜口
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Sharp Corp
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Sharp Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0058—Allocation criteria
    • H04L5/006—Quality of the received signal, e.g. BER, SNR, water filling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/50—Allocation or scheduling criteria for wireless resources
    • H04W72/54—Allocation or scheduling criteria for wireless resources based on quality criteria
    • H04W72/541—Allocation or scheduling criteria for wireless resources based on quality criteria using the level of interference

Definitions

  • the present invention relates to a transmission method determination device, a base station device, a processor, a transmission method determination method, a transmission method determination program, and a transmission device.
  • This application claims priority based on Japanese Patent Application No. 2011-185058 filed in Japan on August 26, 2011 and Japanese Patent Application No. 2012-007049 filed in Japan on January 17, 2012. The contents are incorporated herein.
  • LTE Long Term Evolution
  • IMT-A Long Term Evolution Advanced
  • a clustered DFT-S-OFDM Discrete Fourier Transform Frequency Division Division Multiplexing
  • SC-FDMA Single Carrier-Frequency Division Multiplexing Access
  • OFDM is adopted as an access method in the downlink of LTE or LTE-A (transmission from a base station to a mobile station).
  • Link adaptation is generally used in wireless communication in a cellular system.
  • Link adaptation is a technique for controlling MCS (Modulation and Coding Scheme) configured by a modulation scheme and a coding rate in accordance with the reception level of the mobile station apparatus.
  • MCS Modulation and Coding Scheme
  • the present invention has been made in view of the above points, and provides a transmission method determination device, a base station device, a processor, a transmission method determination method, a transmission method determination program, and a transmission device that can improve throughput and frequency utilization efficiency. .
  • the present invention has been made to solve the above-described problem, and a transmission method determination device according to an aspect of the present invention includes a frequency band allocated to a first transmission device, the frequency band, And determining at least one of a modulation scheme and a coding rate of the first transmission device based on a frequency band assigned to at least one of the second transmission devices using a frequency band that partially overlaps A transmission method determination unit is provided.
  • the transmission method determination unit is based on overlapping information regarding overlapping frequency bands that are allocated redundantly between the first transmission device and at least one second transmission device,
  • the first transmission apparatus may be configured to determine at least one of a modulation scheme and a coding rate.
  • the transmission method determination unit may calculate at least one of a modulation method and a coding rate of the first transmission device based on overlapping information indicating a size of the overlapping frequency band. It may be configured to determine.
  • the transmission method determination unit is configured to perform the first based on overlapping information indicating a ratio between the frequency band allocated to the first transmission device and the overlapping frequency band.
  • the transmission apparatus may be configured to determine at least one of a modulation scheme and a coding rate.
  • the transmission method determination unit determines at least one of a modulation method and a coding rate of the first transmission device based on overlapping information indicating presence / absence of the overlapping frequency band. It may be configured to.
  • the transmission method determination unit calculates transmission quality when equalization is performed by the reception device based on the duplicate information, and based on information indicating the calculated transmission quality
  • the first transmission apparatus may be configured to determine at least one of a modulation scheme and a coding rate.
  • the transmission method determination unit calculates propagation path information when repeated equalization is performed by the reception apparatus based on the overlap information, and based on the calculated propagation path information. And the transmission quality may be calculated.
  • the transmission method determination unit calculates an interference cancellation residual when the reception device repeatedly performs equalization based on the overlap information, and calculates the calculated interference cancellation residual
  • the propagation path information may be calculated based on
  • the transmission method determination unit calculates propagation path information when equalization other than repetitive equalization is performed by the reception apparatus, and the transmission method determination unit calculates the propagation path information based on the calculated propagation path information. Determining at least one of a modulation scheme and a coding rate of one transmission apparatus, and propagation path information when equalization is performed by the receiving apparatus based on at least one of the determined modulation scheme and coding rate and the overlap information It may be configured to calculate.
  • the interference residual determining unit may be configured to calculate an interference cancellation residual for inter-user interference.
  • the interference residual determining unit may be configured to calculate an interference cancellation residual for intersymbol interference.
  • the transmission method determination unit may be configured to assign a frequency band allocated to the first transmission device and a frequency band allocated to at least one of the second transmission devices. Based on the mutual information amount calculated based on the mutual information amount after repeated equalization by the reception device, at least one of the modulation scheme and the coding rate of the first transmission device is determined. May be.
  • a base station apparatus includes the transmission method determining apparatus described above.
  • a processor provides a frequency band allocated to the first transmission apparatus and a frequency band partially overlapping with the frequency band in the transmission method determination apparatus. Based on the frequency band assigned to at least one of the second transmission devices to be used, at least one of the modulation scheme and the coding rate of the first transmission device is determined.
  • the transmission method determination unit includes a frequency band assigned to the first transmission device and a frequency band partially overlapping with the frequency band. And a transmission scheme determination process for determining at least one of a modulation scheme and a coding rate of the first transmission apparatus on the basis of a frequency band assigned to at least one of the second transmission apparatuses using.
  • a transmission method determination program uses a frequency band assigned to the first transmission device and a frequency band partially overlapping with the frequency band for the computer. Based on the frequency band assigned to at least one of the second transmission apparatuses, a procedure for determining at least one of a modulation scheme and a coding rate of the first transmission apparatus is executed.
  • the transmission apparatus which concerns on the other one aspect
  • a transmission device is a code corresponding to overlapping information regarding an overlapping frequency band that is allocated in an overlapping manner between the first transmitting device and at least one second transmitting device.
  • a coding unit for coding at a conversion rate is provided.
  • FIG. 1 is a schematic diagram showing a communication system according to a first embodiment of the present invention. It is the schematic which shows an example of the band allocation which concerns on this embodiment. It is a flowchart showing an example of the MCS determination process which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the transmission rate determination part which concerns on this embodiment. It is the schematic which shows an example of the IUI residual table which concerns on this embodiment. It is another schematic diagram which shows an example of the IUI residual table which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the mobile station apparatus which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on this embodiment.
  • 10 is a flowchart illustrating an example of an MCS determination process according to Modification 1. It is a schematic block diagram which shows an example of a structure of the transmission rate determination part which concerns on this modification. It is the schematic which shows an example of the ISI residual table which concerns on this modification. It is a flowchart showing an example of the MCS determination process which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram which shows an example of a structure of the transmission rate determination part which concerns on this embodiment. It is the schematic which shows an example of the IUI residual table which concerns on this embodiment. 10 is a flowchart illustrating an example of an MCS determination process according to Modification 2.
  • E s / N 0 after equalization is a graph showing the relationship between the output mutual information amount of the equalizer. It is a graph which shows the relationship between the input mutual information content and output mutual information content of the encoder which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the transmission rate determination part which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the mutual information amount calculation part which concerns on this embodiment. It is a graph (maximum duplication rate of 10%) for comparing the throughput characteristics according to the present embodiment and the throughput characteristics when the IUI removal residual ⁇ i, j IUI is a fixed value.
  • a transmitting apparatus that performs data transmission is a mobile station apparatus (user apparatus; UE), and a receiving apparatus that receives data is a base station apparatus (e-NodeB).
  • UE mobile station apparatus
  • e-NodeB base station apparatus
  • an uplink that is transmission from a mobile station apparatus to a base station apparatus will be described, but the present invention is not limited to this, and can also be applied to a downlink that is transmission from a base station apparatus to a mobile station apparatus. It is.
  • the mobile station apparatus or the base station apparatus may be a relay station apparatus that relays transmission.
  • FIG. 1 is a schematic diagram showing a communication system according to the first embodiment of the present invention.
  • the base station apparatus eNB may allocate a frequency band by overlapping a part between at least two or more mobile station apparatuses UEi. That is, the base station apparatus eNB allows band allocation (non-orthogonal access scheme) in which at least some of the frequency bands overlap with at least two of the mobile station apparatuses UE1 to UEI. Note that the base station apparatus eNB may use both the orthogonal access method and the non-orthogonal access method.
  • the base station apparatus eNB determines MCS (Modulation and Coding Scheme) for each mobile station apparatus UEi based on the assigned frequency band overlap rate R i over .
  • MCS is information associated with a modulation scheme and a coding rate.
  • the present invention is not limited to this, and the MCS may be associated with a combination of the number of information bits such as a transport block size (or number), a modulation scheme, and a bandwidth.
  • Each mobile station apparatus UEi transmits a signal using the frequency band allocated by the base station apparatus eNB and the MCS determined by the base station apparatus eNB.
  • FIG. 2 is a schematic diagram illustrating an example of bandwidth allocation according to the present embodiment. This figure shows band allocation when each of the mobile station apparatuses UE1 and UE2 performs clustered DFT-S-OFDM transmission.
  • Clustered DFT-S-OFDM is a transmission method in which a DFT-S-OFDM signal is divided into a plurality of clusters (sets, groups) and transmitted.
  • the allocation indicated by reference sign P21 indicates bandwidth allocation in the case of performing orthogonal access transmission between the plurality of mobile station apparatuses UE1 and UE2. In this case, orthogonality is maintained in the frequency domain, and the same frequency band is not allocated at the same time between the mobile station apparatuses UE1 and UE2.
  • the allocation indicated by the symbol P22 indicates bandwidth allocation in the case of performing transmission in the non-orthogonal access scheme between the plurality of mobile station apparatuses UE1 and UE2. In this case, at least a part of the same frequency band is allocated at the same time between the plurality of mobile station apparatuses UE1 and UE2.
  • the frequency bands denoted by reference numerals r221, r222, and r223 are bands that are assigned to UE1 and UE2 at the same time.
  • FIG. 3 is a flowchart illustrating an example of the MCS determination process according to the present embodiment.
  • the base station apparatus eNB estimates the propagation path characteristic information H i of each mobile station apparatus UEi. Also, the base station apparatus eNB determines the band allocation of the mobile station apparatuses UE1 to UEI from the estimated propagation path characteristics, and based on the determined band allocation, the frequency band overlap rate R i over ( Simply calculating the overlapping rate R i over ). Then, it progresses to step S102.
  • Step S102 The base station apparatus eNB determines an IUI (inter-user interference) removal residual ⁇ i, j IUI in the mobile station apparatus UEi based on the overlap rate R i over calculated in step S101. Thereafter, the process proceeds to step S103.
  • IUI inter-user interference
  • Step S103 The base station apparatus eNB performs post-equalization propagation based on the band allocation determined in step S101, the estimated propagation path characteristic information H i , and the removal residual ⁇ i, j IUI determined in step S102. Calculate the path w i H i bar (with “ ⁇ ” on H i ). However, H i bars, only the propagation path characteristic of the band allocated to the mobile station device UEi from the propagation path characteristic estimated in step S101, in which the base station apparatus eNB is extracted based on the band allocation information. Thereafter, the process proceeds to step S104.
  • Step S104 The base station apparatus eNB transmits the transmission power to noise ratio (E s / N 0 ; transmission quality for each mobile station apparatus UEi based on the equalized propagation path w i H i bar calculated in step S103. ) Is calculated. Thereafter, the process proceeds to step S105.
  • Step S105 The base station apparatus eNB determines the MCS for each mobile station apparatus UEi based on E s / N 0 calculated in step S104.
  • FIG. 4 is a schematic block diagram illustrating an example of the configuration of the transmission rate determination unit 21 according to the present embodiment.
  • the transmission rate determination unit 21 includes an overlap rate calculation unit 210, an IUI residual information storage unit 211, an IUI residual determination unit 212, an equalized propagation path calculation unit 213, a quality calculation unit 214, and an MCS determination unit 215. , And a transmission parameter output unit 216.
  • Bandwidth allocation information and propagation path characteristic information H i are input to the transmission rate determination unit 21 from an allocation determination unit 205 described later.
  • the propagation path characteristic information H i is a frequency response of the propagation path characteristics estimated by the base station apparatus eNB based on SRS (Sounding Reference Signal) transmitted by the mobile station apparatus UEi.
  • SRS Sounding Reference Signal
  • the SRS sequence is known by the mobile station apparatus UEi and the base station apparatus eNB.
  • the duplication rate calculation unit 210 calculates the duplication rate R i over of each mobile station apparatus UEi based on the band allocation information input from the allocation determination unit 205.
  • the overlap rate R i over is “0”.
  • the duplication rate calculation unit 210 outputs the calculated duplication rate R i over to the IUI residual determination unit 212.
  • the IUI residual information storage unit 211 stores an IUI residual table (FIGS. 5 and 6) in which the overlap rate R over and the removal residual ⁇ IUI are associated with each other.
  • the IUI residual determining unit 212 determines the removal residual ⁇ i, j IUI of each mobile station apparatus UEi based on the overlapping rate R i over input from the overlapping rate calculating unit 210. Specifically, the IUI residual determination unit 212 uses the IUI residual table stored in the IUI residual information storage unit 211 to remove the removal residual associated with the overlap rate R i over input from the overlap rate calculation unit 210. selecting the difference delta IUI (the delta IUI for the mobile station device UEi represented by ⁇ i, j IUI).
  • the IUI residual determination unit 212 determines the IUI removal residual ⁇ i, j IUI based on the overlap rate R i over of the mobile station apparatus UEi, but the present invention is not limited to this.
  • the IUI removal residual ⁇ i, j IUI may be determined based on the overlapping rate R j over of the mobile station device UEj that uses a frequency band that overlaps with the mobile station device UEi. In that case, the IUI removal residual ⁇ i, j IUI may be determined to a different value for each mobile station apparatus UEj.
  • the IUI residual determination unit 212 outputs the selected removal residual ⁇ i, j IUI to the post-equalization channel calculation unit 213.
  • the post-equalization channel calculation unit 213 is based on the removal residual ⁇ i, j IUI input from the IUI residual determination unit 212, the band allocation information and the channel characteristic information H i input from the allocation determination unit 205. calculates the equalized channel w i H i bar of each mobile station device UEi using equation (1).
  • w i is an equalization weight, which is a weight when equalization with interference removal processing is performed.
  • H i bar is a frequency response matrix of an allocated band of the i-th mobile station apparatus UEi in N IFFT rows and N IFFT columns, the diagonal component has a frequency response component, and the non-diagonal component is “0”.
  • N IFFT is the number of subcarriers in the system band.
  • the H i, j IUI bar is information obtained by extracting only the propagation path characteristics of the frequency band overlapping with the mobile station apparatus UEi from the frequency components of the propagation path characteristics between the mobile station apparatus UEj and the base station apparatus eNB. .
  • the H i, j IUI bar is “0”.
  • the w i H i bar corresponds to the propagation path characteristic information when equalization is performed.
  • ⁇ 2 is the power of additive white Gaussian noise
  • I is a unit matrix.
  • X H represents the Hermitian matrix of X.
  • the equalized propagation path calculation unit 213 in this embodiment substitutes “1” for ⁇ i ISI .
  • the post-equalization propagation path calculation unit 213 outputs the calculated post-equalization propagation path w i H i bar to the quality calculation unit 214.
  • the quality calculation unit 214 calculates ⁇ i using equation (2) based on the post-equalization propagation path w i H i bar input from the post-equalization propagation path calculation unit 213. In addition, the quality calculation unit 214 calculates ⁇ i using Equation (3). Note that the quality calculation unit 214 in this embodiment substitutes “1” for ⁇ i ISI .
  • ⁇ i is a value obtained by taking an average value in units of modulation symbols for performing DFT (Discrete Fourier Transform) processing on the size of the time replica.
  • DFT Discrete Fourier Transform
  • the quality calculation unit 214 calculates ⁇ i from the removal residual. Based on the calculated ⁇ i and ⁇ i , the quality calculation unit 214 calculates an equivalent amplitude gain ⁇ i using Equation (4).
  • the quality calculation unit 214 calculates E s / N 0 of the mobile station apparatus UEi using Equation (5) based on the calculated equivalent amplitude gain ⁇ i .
  • the quality calculation unit 214 outputs the calculated E s / N 0 of the mobile station apparatus UEi to the MCS determination unit 215.
  • the MCS determination unit 215 determines the MCS for each mobile station apparatus UEi based on E s / N 0 input from the quality calculation unit 214. Specifically, the MCS determination unit 215 stores in advance an MCS table in which E s / N 0 and MCS are associated with each other.
  • the MCS determination unit 215 uses the stored MCS table to select the MCS associated with the E s / N 0 of the mobile station device UEi input from the quality calculation unit 214, whereby the mobile station device UEi Of MCS.
  • the MCS determination unit 215 outputs the determined MCS of each mobile station apparatus UEi to the transmission parameter output unit 216.
  • the transmission parameter output unit 216 outputs the MCS of each mobile station apparatus UEi input from the MCS determination unit 215 and the band allocation information input from the allocation determination unit 205 to the control information generation unit 206 described later.
  • the base station apparatus eNB notifies each mobile station apparatus UEi of the information output from the transmission parameter output unit 216 as control information.
  • FIG. 5 is a schematic diagram illustrating an example of an IUI residual table according to the present embodiment.
  • the IUI residual table has columns of items of an overlap rate R over and a removal residual ⁇ IUI .
  • “d m ” is associated with an overlap rate R over that is greater than or equal to “O m ⁇ 1 ” and lower than “O m ”.
  • “O 1" "d 1" is associated than for low overlap rate R-over-, correlated "d 2" to the lower overlap ratio R-over-than “O 2" in the "O 1" or more It has been.
  • FIG. 6 is another schematic diagram illustrating an example of the IUI residual table according to the present embodiment.
  • the IUI residual table has columns of items of an overlap rate R over and a removal residual ⁇ IUI .
  • R overlap rate
  • ⁇ IUI removal residual
  • FIG. 7 is a schematic block diagram illustrating an example of the configuration of the mobile station apparatus UEi according to the present embodiment.
  • the configuration of each of the mobile station devices UE2 to UEI is the same as that of the mobile station device UE1.
  • the mobile station device UEi has a configuration that a general mobile station device has.
  • the mobile station apparatus UEi has one antenna, but the present invention is not limited to this, and a plurality of antennas are used for transmission and reception, and transmission diversity and MIMO (Multiple Input Multiple Output) transmission are performed. May be.
  • MIMO Multiple Input Multiple Output
  • the number of antennas is not limited to the number of physical antennas, and may be the number of antenna ports or the number of layers. If the antenna port does not need to recognize that there are a plurality of antennas on the receiving device side, the number of antenna ports is set to one.
  • the mobile station apparatus UEi includes a control information receiving unit 109, a coding unit 101, a modulating unit 102, a DFT unit 103, a frequency mapping unit 104, an IFFT (Inverse Fast Fourier transform) unit 105, a reference signal multiplexing unit 106, a transmission processing unit 107, An antenna 108 is included.
  • a control information receiving unit 109 includes a control information receiving unit 109, a coding unit 101, a modulating unit 102, a DFT unit 103, a frequency mapping unit 104, an IFFT (Inverse Fast Fourier transform) unit 105, a reference signal multiplexing unit 106, a transmission processing unit 107, An antenna 108 is included.
  • IFFT Inverse Fast Fourier transform
  • the control information receiving unit 109 receives the control information notified from the base station apparatus eNB.
  • This control information includes band allocation information about the mobile station apparatus UEi, information about MCS, and the like.
  • the control information receiving unit 109 selects a modulation scheme and a coding rate from the MCS included in the received control information.
  • Control information reception section 109 outputs information indicating the selected coding rate to encoding section 101 and outputs information indicating the selected modulation scheme to modulation section 102.
  • Control information receiving section 109 outputs band allocation information included in the control information to frequency mapping section 104.
  • the encoding unit 101 performs encoding of an error correction code on the input data bits at the encoding rate indicated by the information input from the control information receiving unit 109.
  • the error correction code for example, a turbo code or an LDPC (Low Density Parity Check) code is used.
  • the type of error correction code applied by the encoding unit 101 may be determined in advance for each transmission / reception device or each transmission / reception, or may be notified as control information. Also, the type of error correction coding may be determined based on the frequency band duplication rate.
  • the encoding unit 101 generates code bits by puncturing the encoded data bits based on the information indicating the encoding rate input from the control information receiving unit 109.
  • the encoding unit 101 outputs the generated code bit to the modulation unit 102.
  • Modulation section 102 modulates the code bits input from encoding section 101 with the modulation scheme indicated by the information input from control information receiving section 109, thereby generating a modulation symbol.
  • Examples of the modulation scheme include QPSK (Quaternary Phase Shift Keying), 16QAM (16-ary Quadrature Amplitude Modulation), and 64 QAM.
  • Modulation section 102 outputs the generated modulation symbol to DFT section 103.
  • the DFT unit 103 performs discrete Fourier transform on the modulation symbol input from the modulation unit 102 to convert the signal from the time domain to the frequency domain, and outputs the converted signal to the frequency mapping unit 104.
  • the frequency mapping unit 104 arranges the signal input from the DFT unit 103 based on the band allocation information input from the control information receiving unit 109. For example, in the case of non-orthogonal access transmission, the frequency mapping unit 104 of the mobile station apparatus UEi arranges a signal in the same frequency band as the frequency band allocated to the other mobile station apparatus UEj. The frequency mapping unit 104 outputs the arranged signal to the IFFT unit 105. The IFFT unit 105 performs inverse fast Fourier transform on the signal input from the frequency mapping unit 104 to convert the signal from the frequency domain to a time domain signal (data signal). IFFT section 105 outputs the converted data signal to reference signal multiplexing section 106.
  • the reference signal multiplexing unit 106 performs a process of forming a transmission frame by multiplexing a reference signal known by the transceiver in the time domain to the data signal input from the IFFT unit 105.
  • the present invention is not limited to this, and the mobile station apparatus UEi may perform processing for configuring a transmission frame by multiplexing reference signals in the frequency domain.
  • the reference signal multiplexing unit 106 outputs a signal obtained by multiplexing the reference signal to the transmission processing unit 107.
  • the transmission processing unit 107 inserts a CP (Cyclic Prefix) into the signal input from the reference signal multiplexing unit 106.
  • the transmission processing unit 107 converts the signal with the CP inserted into an analog signal by D / A (Digital / Analog) conversion, and up-converts the converted signal to a radio frequency.
  • the transmission processing unit 107 amplifies the up-converted signal with a PA (Power Amplifier), and transmits the amplified signal via the antenna 108.
  • CP Cyclic Prefix
  • FIG. 8 is a schematic block diagram illustrating an example of the configuration of the base station apparatus eNB according to the present embodiment. Although this figure shows the structural example of the base station apparatus eNB which has one receiving antenna, this invention is not restricted to this, The base station apparatus eNB may have a some receiving antenna.
  • a base station apparatus eNB includes an antenna 201, a reception processing unit 202, a reference signal separation unit 203, a channel estimation unit 204, an allocation determination unit 205, a transmission rate determination unit 21, a control information generation unit 206, and a control information transmission.
  • Unit 207 FFT (Fast Fourier transformation) unit 208, demapping unit 209, and iterative equalization unit T1.
  • the iterative equalization unit T1 includes residual calculation units 221-1 to 221-I, soft canceller units 222-1 to 222-I, equalization units 223-1 to 223-I, and an IDFT (Inverse Discrete Fourier transform) unit.
  • the process of the repetition equalization unit T1 is repeatedly performed on a signal in a predetermined processing unit (for example, a signal unit transmitted at one transmission opportunity or a signal unit performed DFT) (repetition etc.). Also referred to as equalization process or turbo equalization process). Moreover, the process of the repetition equalization part T1 may be a reception process by SIC.
  • the receiving unit 202 down-converts the signal received by the antenna 201 to a baseband frequency, and generates a digital signal by performing A / D conversion on the down-converted signal.
  • the receiving unit 202 removes the cyclic prefix from the generated digital signal, and outputs the signal after the removal to the reference signal separation unit 203.
  • the reference signal separation unit 203 separates the signal input from the reception processing unit 202 into a reference signal (SRS) and a data signal.
  • the reference signal separation unit 203 outputs the separated reference signal to the propagation path estimation unit 204, and outputs the separated data signal to the FFT unit 208.
  • SRS reference signal
  • the propagation path estimation unit 204 estimates a propagation path characteristic (frequency response) for each mobile station apparatus UEi based on the reference signal input from the reference signal separation unit 203.
  • the propagation path estimation unit 204 outputs propagation path characteristic information H i indicating the estimated propagation path characteristics to the assignment determination unit 205 and equalization units 223-1 to 223-I. Further, channel estimation section 204, channel characteristic information H i propagation path characteristic information H i Bar extracted by the band allocation information to output to the channel multiplication unit 230-i (not shown).
  • Allocation determining unit 205 based on the propagation path characteristic information H 1 ⁇ H i input from the channel estimation unit 204, determines the bandwidth allocation of each mobile station devices UE1 ⁇ UEI.
  • the allocation determination unit 205 allows the bandwidth allocation of the non-orthogonal access scheme (see FIG. 2).
  • the allocation determining unit 205 outputs information indicating the determined band allocation (band allocation information) and the propagation path characteristic information H i to the transmission rate determining unit 21.
  • Transmission rate determining unit 21 based on the band allocation information inputted from the allocation determining unit 205 and the propagation path characteristic information H i, by performing the MCS determination processing described above, to determine the MCS for each mobile station apparatus UEi.
  • the transmission rate determining unit 21 outputs information indicating the determined MCS and the band allocation information input from the allocation determining unit 205 to the control information generating unit 206.
  • the control information generation unit 206 generates control information by converting the information input from the transmission rate determination unit 21 into a predetermined control information format.
  • the control information generation unit 206 outputs the generated control information to the control information transmission unit 207.
  • the control information generation unit 206 converts the information input from the transmission rate determination unit 21 into a demapping unit 209, a residual calculation unit 221-i, a demodulation unit 226-i, a decoding unit 227-i, and a replica generation unit 228-. output to i.
  • the control information transmission unit 207 notifies the control information input from the control information generation unit 206 to the mobile station apparatuses UE1 to UEI for the next transmission opportunity. These pieces of control information are held until the next transmission opportunity by the base station apparatus eNB (for example, the control information generation unit 206), and used when performing signal processing for the next transmission opportunity.
  • the FFT unit 208 performs fast Fourier transform on the data signal input from the reference signal separation unit 203 to convert the data signal into a frequency domain data signal, and outputs the converted signal to the demapping unit 209.
  • the demapping unit 209 extracts a signal of a band allocated to each mobile station apparatus UEi based on the band allocation information input from the control information generation unit 206. This band allocation information is equivalent to the band allocation information included in the control information notified from the base station apparatus eNB to the plurality of mobile station apparatuses UE1 to UEI.
  • the demapping unit 209 outputs a signal extracted from the band allocated to the mobile station apparatus UEi to the soft canceller unit 222-i.
  • the residual calculation unit 221-i stores in advance correspondence information in which the MCS and the average desired signal value s (average power) are associated with each other. Based on the correspondence information, the residual calculation unit 221-i determines average desired signal values s i and s j corresponding to the MCSs of the mobile station apparatuses UEi and UEj indicated by the information input from the control information generation unit 206. To do. Note that the average desired signal values s i and s j are vectors having components for each modulation symbol, and have components for the number of modulation symbols (also referred to as the number of DFT symbols) in units for performing DFT processing.
  • the residual calculation unit 221-i includes the determined average desired signal values s i and s j , the time replica input from the replica generation unit 228-i described later, and the band allocation information input from the control information generation unit 206
  • the inter-symbol interference (ISI: Inter Symbol Interference) cancellation residual ⁇ i ISI and the inter-user interference (IUI; Inter-User Interference) cancellation residual ⁇ i, j IUI are calculated.
  • the residual calculation unit 221-i calculates the removal residuals ⁇ i ISI and ⁇ i, j IUI using the equations (6) and (7).
  • the residual calculation unit 221-i calculates the removal residual ⁇ i, j IUI using Equation (7).
  • the removal residual ⁇ i, j IUI of the mobile station apparatus UEj that is not assigned the same frequency band as that of the mobile station apparatus UEi is “0”.
  • the signal s i is an average desired signal value of the mobile station apparatus UEi
  • s i hat represents a replica of a modulation symbol (referred to as a time replica) of the mobile station apparatus UEi
  • E [X] represents a time average of X in the above processing unit.
  • Tr [X] is the sum of the diagonal components of the matrix X.
  • Ni and Nj are the numbers of DFT symbols for the signals of the mobile station apparatuses UEi and UEj, respectively.
  • the signal s j IUI is an average desired signal value of the mobile station apparatus UEj that causes inter-user interference with respect to the mobile station apparatus UEi.
  • the signal s j IUI hat represents a time replica of the mobile station apparatus UEj.
  • the residual calculation unit 221-i outputs the calculated residuals ⁇ i ISI and ⁇ i, j IUI for the mobile station apparatus UEi to the equalization unit 223-i.
  • the soft canceller unit 222-i stores the signal R i (also referred to as a received signal R i ) of the mobile station apparatus UEi input from the demapping unit 209.
  • the soft canceller unit 222-i receives a frequency replica of the mobile station apparatus UEi from a propagation path multiplication unit 230i described later, and an IUI frequency replica of the mobile station apparatus UEj from an IUI extraction unit 231-j described later.
  • the frequency replica of the mobile station apparatus UEi is a replica corresponding to a signal received by the base station apparatus eNB from the mobile station apparatus UEi.
  • the IUI frequency replica of the mobile station apparatus UEi is a signal replica obtained by extracting only signals that cause inter-user interference to the mobile station apparatus UEi from among the signals received from the mobile station apparatus UEj by the base station apparatus eNB. is there.
  • Each replica is a frequency domain replica.
  • the frequency replica and the IUI frequency replica of the mobile station apparatus UEi are expressed by equations (8) and (9), respectively.
  • S i hat (with “ ⁇ ” added to S i ) is a frequency replica of the mobile station apparatus UEi.
  • the S IUI j hat is a frequency replica of the mobile station apparatus UEj to which a frequency band overlapping with the mobile station apparatus UEi is allocated among the frequency replicas of the mobile station apparatus UEj. In the case of the mobile station apparatus UEj that does not overlap at all, 0 ".
  • the soft canceller unit 222-i cancels (subtracts, deletes, and removes) the frequency replica and the IUI frequency replica of the mobile station apparatus UEi from the stored received signal R i of the mobile station apparatus UEi, thereby generating a signal.
  • R i tilde is generated.
  • the signal R i tilde is represented by equation (10).
  • Soft canceller unit 222-i outputs the generated signal R i tilde to the equalization section 223-i. However, in the first iteration of turbo equalization processing, the soft canceller unit 222-i receives no input from the demapping unit 209 because there is no input from the propagation path multiplication unit 230-i and IUI extraction unit 231-j. The signal R i is output to the equalization unit 223-i as the signal R i tilde.
  • the equalization unit 223-i receives the propagation path characteristic information input from the propagation path estimation unit 204, the removed residuals ⁇ i ISI and ⁇ i, j IUI input from the residual calculation unit 221-i, and additive white based on the power sigma 2 of Gaussian noise, it is multiplied by a weight w i of the MMSE criterion. Specifically, the equalizing unit 223-i multiplies the weight w i by using Equation (11). The calculation formula of the weight w i is the same as the formula for the weights w i in the formula (1).
  • the equalizing unit 223-i performs equalization processing by multiplying the signal R i tilde input from the soft canceller unit 222-i by the calculated weight w i .
  • the equalization unit 223-i outputs the equalized signal to the IDFT unit 224-i. Further, the equalizing unit 223-i calculates ⁇ i using the equation (2) based on the propagation path characteristic and the calculated weight w i , and outputs the calculated ⁇ i to the combining unit 225-i ( Not shown).
  • the IDFT unit 224-i performs inverse discrete fast Fourier transform on the signal input from the equalization unit 223-i, thereby converting the signal from the frequency domain to the time domain.
  • the IDFT unit 224-i outputs the converted signal to the synthesis unit 225-i.
  • the synthesizing unit 225-i calculates ⁇ i using Expression (12) based on the time replica input from the replica generation unit 228-i.
  • s i hat (k) is the k-th component of vector s i hat. That is, ⁇ i is a value obtained by taking an average value for the size of the time replica in units of modulation symbols for which DFT processing is performed.
  • the synthesis unit 225-i receives the input from the IDFT unit 224-i.
  • a signal z i represented by Expression (13) is generated from the signal (F H w i R i tilde). That is, the synthesis unit 225-i adds the desired signal canceled by the soft canceller unit 222-i to the signal input from the IDFT unit 224-i.
  • the matrix F H represents an IDFT (Inverse Discrete Fast Fourier Transform) by the IDFT unit 224-i as a matrix.
  • the synthesizer 225-i outputs the calculated signal z to the demodulator 226-i.
  • the demodulation unit 226-i is a modulation method indicated by the information input from the control information generation unit 206, and uses the modulation method corresponding to the MCS of the mobile station apparatus UEi to input the signal input from the combining unit 225-i. Demodulate z i . Thereby, the demodulation unit 226-i obtains an LLR (Log Likelihood Ratio) in the time domain. The demodulator 226-i outputs the obtained LLR to the decoder 227-i.
  • LLR Log Likelihood Ratio
  • the decoding unit 227-i is the coding rate indicated by the information input from the control information generation unit 206, and is input from the demodulation unit 226-i using the coding rate corresponding to the MCS of the mobile station apparatus UEi.
  • the LLR is decoded by error correction decoding.
  • the decoding unit 227-i obtains a data bit.
  • the decoding unit 227-i outputs the obtained data bits.
  • the obtained data bits are output to the replica generation unit 228-i.
  • the decoding unit 227-i determines whether or not there are no errors by, for example, determining whether or not errors are no longer detected by cyclic redundancy check (CRC: Cyclic Redundancy Check).
  • the replica generation unit 228-i uses the coding rate and modulation scheme indicated by the information input from the control information generation unit 206, and uses the coding rate and modulation scheme corresponding to the MCS of the mobile station apparatus UEi.
  • the data bits input from the unit 227-i are encoded and modulated. Thereby, the replica generation unit 228-i generates a modulation symbol of the mobile station apparatus UEi, that is, a time replica.
  • the replica generation unit 228-i outputs the generated time replica of the mobile station apparatus UEi to the residual calculation units 228-1 to 228-I, the synthesis unit 225-i, and the DFT unit 229-i.
  • the DFT unit 229-i performs discrete Fourier transform on the time replica of the mobile station apparatus UEi input from the replica generation unit 228-i, thereby transforming the converted signal from the time domain to the frequency domain, and the converted signal to the propagation path The result is output to the multiplier 230-i.
  • the propagation path multiplication unit 230-i multiplies the signal input from the DFT unit 229-i by the propagation path characteristic indicated by the propagation path characteristic information input from the propagation path estimation unit 204. Thereby, the propagation path multiplying unit 230-i generates a frequency replica of the mobile station apparatus UEi.
  • the propagation path multiplication unit 230-i outputs the generated frequency replica to the soft canceller unit 222-i and the IUI extraction unit 231-i.
  • the IUI extraction unit 231-i uses the frequency replica input from the propagation path multiplying unit 230-i to determine whether the mobile station device UEi and the mobile station device UEj A frequency replica (IUI frequency replica of the mobile station apparatus UEj) of the frequency band assigned in duplicate is extracted.
  • the IUI extraction unit 231-i outputs the extracted IUI frequency replica of the mobile station apparatus UEj to the soft canceller unit 222-j.
  • the IUI residual determination unit 212 removes the residual when the base station apparatus eNB repeatedly performs equalization based on the overlap rate R i over. Determine ⁇ IUI .
  • the equalized propagation path calculation unit 213 calculates the post-equalization propagation path w i H i bar based on the removal residual ⁇ IUI determined by the IUI residual determination unit 212.
  • the quality calculation unit 214 calculates E s / N 0 based on the post-equalization propagation path w i H i bar calculated by the post-equalization propagation path calculation unit 213.
  • the MCS determination unit 215 determines the MCS of the mobile station apparatus UEi based on the information indicating E s / N 0 calculated by the quality calculation unit 214.
  • the transmission rate determining unit 21 determines the mobile station apparatus UEi based on the frequency band overlap rate R i over that is allocated to the mobile station apparatus UEi and at least one mobile station apparatus UEj (j ⁇ i). Of MCS. That is, the transmission rate determining unit 21 determines the MCS of the mobile station apparatus UEi based on the frequency band allocated to the mobile station apparatus UEi and the frequency band allocated to at least one mobile station apparatus UEj. Thereby, the communication system can determine MCS which considered the influence in the frequency band which overlaps with the mobile station apparatus UEj also in the case of a non-orthogonal access system.
  • the communication system does not have an MCS with a low transmission rate considering the IUI more than necessary when determining the MCS, or an MCS with a high transmission rate that does not satisfy the required quality without considering the IUI. MCS with a proper transmission rate can be determined. Therefore, the communication system can appropriately perform link adaptation even when using a non-orthogonal access scheme that uses iterative equalization for reception processing, and can improve frequency utilization efficiency or throughput.
  • 9 and 10 are schematic diagrams showing throughput characteristics. These figures show the throughput characteristics in the transmission of the non-orthogonal access method using turbo equalization for the reception processing.
  • the horizontal axis is E s / N 0 and the vertical axis is the throughput.
  • 9 and 10 show that the throughput varies depending on the value of the removal residual ⁇ i, j IUI .
  • FIG. 9 is a diagram when the maximum value of the duplication rate R i over is 10%. This figure shows that, for example, when the removal residual ⁇ i, j IUI is “0.2”, the removal residual ⁇ i, j IUI is “0.4” or “1.0”. Represents a high throughput.
  • FIG. 10 is a diagram when the maximum value of the duplication rate R i over is 30%. This figure shows that, for example, when the removal residual ⁇ i, j IUI is “0.4”, the removal residual ⁇ i, j IUI is “0.2” or “1.0”. , E s / N 0 is “6” or higher, indicating that the throughput is high.
  • the base station apparatus eNB calculates the removal residual ⁇ IUI based on the overlap rate R i over , so that throughput characteristics can be improved.
  • Modification 1 Modification 1 will be described. Note that the communication system according to the first modification is the same as that in FIG. 1, and an example of the configuration of the mobile station apparatus UEi is the same as that in FIG.
  • FIG. 11 is a flowchart illustrating an example of the MCS determination process according to the present modification.
  • the MCS determination process according to the first modification (FIG. 11) and the MCS determination process according to the first embodiment (FIG. 3) are compared, the processes of steps S202 and S203 are different. The other processes are the same as those in FIG.
  • Step S202 The base station apparatus eNB determines an ISI (intersymbol interference) removal residual ⁇ i ISI in the mobile station apparatus UEi based on the overlapping rate R i over calculated in step S101. Then, it progresses to step S203.
  • the base station apparatus eNB assigns the bandwidth determined in step S101, the estimated channel characteristic information H i , the removal residual ⁇ i, j IUI determined in step S102, and the removal residual determined in step S202. Based on the difference ⁇ i ISI , a post-equalization propagation path w i H i bar is calculated. Thereafter, the process proceeds to step S104.
  • ISI symbol interference
  • the base station apparatus eNB according to the modification 1 includes a transmission rate determination unit 21a instead of the transmission rate determination unit 21 of the base station apparatus eNB (FIG. 8) according to the first embodiment.
  • FIG. 12 is a schematic block diagram illustrating an example of the configuration of the transmission rate determination unit 21a according to the first modification.
  • the transmission rate determination unit 21a (FIG. 12) and the transmission rate determination unit 21 (FIG. 4) are compared, the ISI residual information storage unit 211a, the ISI residual determination unit 212a, and the post-equivalent propagation path calculation unit 213a are different.
  • the functions of other components are the same as those of the first embodiment, description of the same functions as those of the first embodiment is omitted.
  • the ISI residual information storage unit 211a stores an ISI residual table (FIG. 13) in which the overlap rate R over and the removal residual ⁇ ISI are associated with each other.
  • the ISI residual determination unit 212a determines the removal residual ⁇ i ISI for each mobile station apparatus UEi based on the overlap rate R i over input from the overlap rate calculation unit 210. Specifically, the ISI residual determination unit 212a, based on the ISI residual table stored in the ISI residual information storage unit 211a, removes residuals associated with the overlap rate R i over input from the overlap rate calculation unit 210. selecting the difference delta ISI (the delta ISI for the mobile station device UEi represented by delta i ISI). The ISI residual determination unit 212a outputs the selected removal residual ⁇ i ISI to the post-equalization propagation path calculation unit 213a.
  • equalization channel calculating unit 213a removes residual input from the IUI residual determining unit 212 delta IUI, removing residual input from the ISI residual determining unit 212a delta ISI, and the input from the allocation determining unit 205 Based on the obtained band allocation information and propagation path characteristic information H i , an equalized propagation path w i H i bar for each mobile station apparatus UEi is calculated using Equation (1).
  • the post-equalization propagation path calculation unit 213a outputs the calculated post-equalization propagation path w i Hi bar to the quality calculation unit 214.
  • FIG. 13 is a schematic diagram illustrating an example of an ISI residual table according to the present modification.
  • the ISI residual table has columns of items of an overlap rate R over and a removal residual ⁇ ISI .
  • “d ′ m ” is associated with an overlap rate R over that is greater than or equal to “O ′ m ⁇ 1 ” and lower than “O ′ m ”.
  • 0 ⁇ O ′ m ⁇ 1 ⁇ O ′ m ⁇ 1 and 0 ⁇ d ′ m ⁇ 1 ⁇ d ′ m ⁇ 1 are satisfied.
  • the relationship of overlapping ratio R-over-removal residual delta ISI is overlap rate R-over-the higher the removal residual decreases low, a relationship as removing residual high overlap rate R-over-increases.
  • ' "1 is associated with d" to the low overlap rate R-over-than "1 O"', with respect to lower overlap ratio R-over-than '' 2 O "in” one or more O "' “D 2 ” is associated.
  • the IUI residual determination unit 212 and the ISI residual determination unit 212a repeatedly perform equalization by the base station apparatus eNB based on the overlap rate R i over. determining remove residual delta IUI and delta ISI in the case of performing.
  • Equalized channel calculating section 213a based on the removal residual delta ISI removal residual IUI residual determination unit 212 has determined delta IUI and ISI residual determination unit 212a has been determined, the equalized channel w i Calculate the Hi bar.
  • the quality calculation unit 214 calculates E s / N 0 based on the post-equalization propagation path w i H i bar calculated by the post-equalization propagation path calculation unit 213.
  • the MCS determination unit 215 determines the MCS of the mobile station apparatus UEi based on the information indicating E s / N 0 calculated by the quality calculation unit 214.
  • the transmission rate determining unit 21 determines the mobile station apparatus UEi based on the frequency band overlap rate R i over that is allocated to the mobile station apparatus UEi and at least one mobile station apparatus UEj (j ⁇ i).
  • MCS mobile station apparatus
  • the communication system considers the IUI and ISI more than necessary when determining the MCS, and sets the MCS with a low transmission rate, or the MCS with a high transmission rate that does not satisfy the required quality without considering the IUI and ISI.
  • the communication system can appropriately perform link adaptation even when using a non-orthogonal access scheme that uses iterative equalization for reception processing, and can improve frequency utilization efficiency or throughput.
  • the post-equalization channel calculation unit 213a calculates the post-equalization channel w i Hi bar based on the removal residual ⁇ i ISI calculated by the ISI residual determination unit 212a.
  • the post-equalization channel calculation unit 213a substitutes “1” for ⁇ i, j IUI , for example, but the present invention is not limited to this.
  • FIG. 14 is a flowchart showing an example of the MCS determination process according to the second embodiment of the present invention.
  • Step S301 The base station apparatus eNB estimates the propagation path characteristic information H i of each mobile station apparatus UEi, and determines the band allocation of the mobile station apparatuses UE1 to UEI from the estimated propagation path characteristic information H i .
  • the base station apparatus eNB calculates the duplication rate R i over in each mobile station apparatus UEi based on the determined bandwidth allocation. Thereafter, the process proceeds to step S302.
  • Step S302 The base station apparatus eNB calculates a post-equalization propagation path w i H i bar based on the bandwidth allocation determined in step S301. Thereafter, the process proceeds to step S303.
  • Step S303 The base station apparatus eNB calculates E s / N 0 based on the post-equalization propagation path w i Hi bar calculated in step S302.
  • the base station apparatus eNB determines MCS (referred to as the first MCS) based on the calculated E s / N 0 . Thereafter, the process proceeds to step S304.
  • Step S304 The base station apparatus eNB determines the removal residual ⁇ i, j IUI in the mobile station apparatus UEi based on the overlap rate R i over calculated in step S301 and the MCS calculated in step S303. Thereafter, the process proceeds to step S305.
  • Step S305 The base station apparatus eNB performs post-equalization propagation based on the band allocation determined in step S101, the estimated channel characteristic information H i , and the removal residual ⁇ i, j IUI determined in step S304. Calculate the path w i H i bar. Thereafter, the process proceeds to step S306.
  • Step S306 The base station apparatus eNB, based on the calculated equalized channel w i H i bar in step S305, calculates the E s / N 0 for each mobile station apparatus UEi. Thereafter, the process proceeds to step S307.
  • Step S307 The base station apparatus eNB determines the MCS (referred to as the second MCS) of each mobile station apparatus UEi based on the E s / N 0 calculated in Step S306. Note that the base station apparatus eNB notifies the mobile station apparatus UEi of control information including information indicating the second MCS of the mobile station apparatus UEi.
  • the base station apparatus eNB and the mobile station apparatus UEi communicate with each other with a modulation scheme and a coding rate corresponding to the second MCS.
  • the base station apparatus eNB includes a transmission rate determining unit 21b instead of the transmission rate determining unit 21 of the base station apparatus eNB (FIG. 8) according to the first embodiment.
  • FIG. 15 is a schematic block diagram illustrating an example of the configuration of the transmission rate determining unit 21b according to the present embodiment.
  • the transmission rate determination unit 21b (FIG. 15) and the transmission rate determination unit 21 (FIG. 4) are compared, the first post-equalization channel calculation unit 217b, the first quality calculation unit 218b, the first MCS determination unit 219b, the IUI remaining
  • the difference information storage unit 211b and the IUI residual determination unit 212b are different.
  • description of the same functions as those of the first embodiment is omitted.
  • the first post-equalization channel calculation unit 217b uses the equation (1) based on the band allocation information input from the allocation determination unit 205 and the post-equalization channel w i H i bar, and uses each mobile station apparatus UEi.
  • the post-equalization propagation path w i H i bar for is calculated.
  • the first post-equalization channel calculation unit 217b substitutes “1” for the removal residual ⁇ i, j IUI and ⁇ i ISI in the equation (1). This substitution corresponds to the fact that interference (ISI and IUI) that can be removed by turbo equalization is not removed without being understood, that is, the replica is not fed back without being repeatedly iterated.
  • the first post-equalization propagation path calculation unit 217b calculates the equalization weight w i when the base station apparatus eNB performs equalization other than iterative equalization (equalization with interference removal).
  • First equalized channel calculating section 217b the calculated equalized channel w i H i bars, and outputs to the first quality calculator 218b.
  • the first quality calculation unit 218b calculates ⁇ i using equation (2) based on the post-equalization propagation path w i H i bar input from the first post-equalization propagation path calculation unit 217b, ⁇ i is calculated using (3).
  • the first quality calculation unit 218b calculates an equivalent amplitude gain ⁇ i using Equation (4) based on the calculated ⁇ i and ⁇ i , and uses Equation (5) based on the calculated equivalent amplitude gain ⁇ i. Is used to calculate E s / N 0 of the mobile station apparatus UEi.
  • the first quality calculation unit 218b outputs the calculated E s / N 0 of the mobile station apparatus UEi to the first MCS determination unit 219b.
  • the first MCS determination unit 219b determines the MCS (first MCS) for each mobile station apparatus UEi based on E s / N 0 input from the first quality calculation unit 218b.
  • the first MCS determination unit 219b outputs the determined first MCS of each mobile station apparatus UEi to the IUI residual determination unit 212b.
  • the IUI residual information storage unit 211b stores, for each MCS, an IUI residual table (FIG. 16) in which the overlap rate R over and the removal residual ⁇ IUI are associated with each other. That is, the correspondence between the overlap rate R over and the removal residual ⁇ IUI includes different ones depending on the MCS.
  • the IUI residual determination unit 212b Based on the overlap rate R i over input from the overlap rate calculation unit 210 and the first MCS input from the first MCS determination unit 219b, the IUI residual determination unit 212b performs the removal residual ⁇ i, of each mobile station apparatus UEi , j Determine the IUI . Specifically, the IUI residual determination unit 212b reads the IUI residual table of the first MCS input from the first MCS determination unit 219b among the IUI residual tables stored in the IUI residual information storage unit 211b. The IUI residual determination unit 212b selects, from the read IUI residual table, the removal residual ⁇ i, j IUI associated with the overlap rate R i over input from the overlap rate calculation unit 210.
  • the IUI residual determination unit 212b outputs the determined removal residual ⁇ i, j IUI to the post-equalization channel calculation unit 213.
  • the MCS determination unit 215 determines the MCS (second MCS) based on the removal residual ⁇ i, j IUI determined by the IUI residual determination unit 212b.
  • the MCS determination unit 215 outputs the determined second MCS as the MCS of the mobile station apparatus UEi to the transmission parameter output unit 216.
  • FIG. 16 is a schematic diagram illustrating an example of an IUI residual table according to the present embodiment.
  • the IUI residual table has columns of items of an overlap rate R over and a removal residual ⁇ IUI .
  • “d m + m m ” is associated with an overlap rate R over that is greater than or equal to “O m ⁇ 1 ” and lower than “O m ”.
  • “O 1" "d 1 + m 1” is associated for low overlap rate R-over-than "O 1" or the "d 2 + m 2 for low overlap rate R-over-than” O 2 ""Is associated.
  • m 1 , m 2 ,..., M M reflect a decrease in interference removal capability of turbo equalization due to the modulation scheme, and are values of 0 or more.
  • m m the more the higher the number of levels or the coding rate is high, a large value.
  • 0 ⁇ O m ⁇ 1 ⁇ O m ⁇ 1 and 0 ⁇ d m ⁇ 1 + m m ⁇ 1 ⁇ d m + m m ⁇ 1 are satisfied. That is, for the same MCS, relationship overlap rate R-over-removal residual delta IUI may overlap rate R-over-the higher the removal residual is reduced lower, removing the residual higher overlap rate R-over-increase It is a relationship.
  • the first quality calculation unit 218b performs post-equalization propagation path w i H i bar when equalization other than repetitive equalization is performed by the reception apparatus. Is calculated.
  • the 1MCS determining unit 219b based on the first post-equalization quality calculator 218b has calculated the propagation path w i H i bars, determines a first 1MCS mobile station UEi.
  • the IUI residual determination unit 212b determines the removal residual ⁇ i, j IUI of each mobile station apparatus UEi based on the overlap rate R i over and the first MCS determined by the first MCS determination unit 219b.
  • the equalized propagation path calculation unit 213 calculates the post-equalization propagation path w i H i bar based on the removal residual ⁇ IUI determined by the IUI residual determination unit 212.
  • the quality calculation unit 214 calculates E s / N 0 based on the post-equalization propagation path w i H i bar calculated by the post-equalization propagation path calculation unit 213.
  • the MCS determination unit 215 determines the second MCS of the mobile station apparatus UEi based on the information indicating E s / N 0 calculated by the quality calculation unit 214.
  • the transmission rate determining unit 21b in the case of performing signal detection by the turbo equalization during transmission by non-orthogonal access method, removing residual IUI depending on overlap rate R i-over-the interim MCS (the MCS) delta IUI It determines, determines the MCS (the MCS) using the determined removed residual delta IUI.
  • the communication system may consider an IUI that is unnecessarily considered at the time of determining the MCS, or an MCS with a low transmission rate, or an MCS with a high transmission rate that does not satisfy the required quality without considering the IUI.
  • the MCS with an appropriate transmission rate can be determined.
  • the communication system can reflect the degradation of the interference removal capability of turbo equalization by the modulation method in the determination of the MCS. Therefore, the communication system can appropriately perform link adaptation even when using a non-orthogonal access scheme that uses iterative equalization for reception processing, and can improve frequency utilization efficiency or throughput.
  • Modification 2 Modification 2 will be described. Note that the communication system according to the second modification is the same as that in FIG. 1, and an example of the configuration of the mobile station apparatus UEi is the same as that in FIG.
  • FIG. 17 is a flowchart illustrating an example of the MCS determination process according to the second modification.
  • the processes of steps S404 and S405 are different.
  • the other processes are the same as those in FIG.
  • Step S404 The base station apparatus eNB determines the removal residual ⁇ i ISI in the mobile station apparatus UEi based on the overlap rate R i over calculated in step S301 and the MCS calculated in step S303. Thereafter, the process proceeds to step S405. (Step S405) The base station apparatus eNB assigns the bandwidth determined in step S101, the estimated channel characteristic information H i , the removal residual ⁇ i, j IUI determined in step S304, and the removal residual determined in step S404. Based on the difference ⁇ i ISI , a post-equalization propagation path w i H i bar is calculated. Thereafter, the process proceeds to step S306.
  • the base station apparatus eNB according to Modification 2 includes a transmission rate determination unit 21c instead of the transmission rate determination unit 21 of the base station apparatus eNB (FIG. 8) according to the first embodiment.
  • FIG. 18 is a schematic block diagram illustrating an example of the configuration of the transmission rate determination unit 21c according to the present modification.
  • the transmission rate determination unit 21c (FIG. 18) is compared with the transmission rate determination unit 21b (FIG. 15)
  • the ISI residual information storage unit 211c, the ISI residual determination unit 212c, and the post-equivalent propagation path calculation unit 213a are different.
  • description of the same functions as those of the second embodiment is omitted.
  • the ISI residual information storage unit 211c stores, for each MCS, an ISI residual table (FIG. 19) in which the overlap rate R over and the removal residual ⁇ ISI are associated with each other. That is, the correspondence between the overlap rate R over and the removal residual ⁇ ISI includes different values depending on the MCS.
  • the ISI residual determination unit 212c based on the overlap rate R i over input from the overlap rate calculation unit 210 and the MCS indicated by the information input from the first MCS determination unit 219b, the removal residual ⁇ of each mobile station apparatus UEi i Determine the ISI .
  • the ISI residual determination unit 212c reads the ISI residual table of the first MCS input from the first MCS determination unit 219b among the ISI residual tables stored in the ISI residual information storage unit 211c.
  • the ISI residual determination unit 212c selects, from the read ISI residual table, the removal residual ⁇ i ISI associated with the duplication rate R i over input from the duplication rate calculation unit 210.
  • the ISI residual determination unit 212c outputs the determined removal residual ⁇ i ISI to the post-equalization channel calculation unit 213a.
  • equalization channel calculating unit 213a removes residual input from the IUI residual determining unit 212b delta IUI, removing residual input from the ISI residual determining unit 212c delta ISI, and the input from the allocation determining unit 205 Based on the obtained band allocation information and propagation path characteristic information H i , an equalized propagation path w i H i bar for each mobile station apparatus UEi is calculated using Equation (1).
  • the post-equalization propagation path calculation unit 213a outputs the calculated post-equalization propagation path w i Hi bar to the quality calculation unit 214.
  • the MCS determination unit 215 outputs the determined second MCS as the MCS of the mobile station apparatus UEi to the transmission parameter output unit 216.
  • FIG. 19 is a schematic diagram illustrating an example of an ISI residual table according to the present modification.
  • the ISI residual table has columns of items of an overlap rate R over and a removal residual ⁇ ISI .
  • “d ′ m + m ′ m ” is associated with an overlap rate R over that is greater than or equal to “O ′ m ⁇ 1 ” and lower than “O ′ m ”.
  • '' 1 + m '1 is associated
  • "O d"' for low overlap rate R-over-than "1 O '' for low overlap rate R-over-than” O '2 "in 1" or more “D ′ 2 + m ′ 2 ” is associated.
  • m ′ 1 , m ′ 2 ,..., M ′ M reflect a decrease in the interference removal capability of turbo equalization due to the modulation method, and is a value of 0 or more.
  • m ′ m increases as at least one of the multi-value number and the coding rate increases.
  • the present invention is not limited to this, and m ′ m may have a lower value as at least one of the multi-value number and the coding rate becomes lower.
  • 0 ⁇ O ′ m ⁇ 1 ⁇ O ′ m ⁇ 1 and 0 ⁇ d ′ m ⁇ 1 + m ′ m ⁇ 1 ⁇ d ′ m + m ′ m ⁇ 1 are satisfied. That is, for the same MCS, relationship overlap rate R-over-removal residual delta ISI is overlap rate R-over-the higher the removal residual is reduced lower, removing the residual higher overlap rate R-over-increase It is a relationship.
  • the ISI residual determination unit 212c based on the overlap rate R i over and the first MCS determined by the first MCS determination unit 219c, the removal residual ⁇ i of each mobile station apparatus UEi. Determine the ISI .
  • Equalized channel calculating section 213a based on the removal residual delta ISI removal residual IUI residual determination unit 212 has determined delta IUI and ISI residual determination unit 212c has been determined, the equalized channel w i Calculate the Hi bar.
  • the quality calculation unit 214 calculates E s / N 0 based on the post-equalization propagation path w i H i bar calculated by the post-equalization propagation path calculation unit 213.
  • the MCS determination unit 215 determines the MCS of the mobile station apparatus UEi based on the information indicating E s / N 0 calculated by the quality calculation unit 214.
  • the transmission rate determining unit 21c in the case of performing signal detection by the turbo equalization during transmission by non-orthogonal access method, removing the residual according to the overlap rate R i-over-the interim MCS (the MCS) delta IUI and delta determine the ISI, it determines the MCS using the determined removed residual delta IUI and delta ISI.
  • the communication system considers the IUI and ISI more than necessary when determining the MCS, and sets the MCS with a low transmission rate, or the MCS with a high transmission rate that does not satisfy the required quality without considering the IUI and ISI.
  • the communication system can appropriately perform link adaptation even when using a non-orthogonal access scheme that uses iterative equalization for reception processing, and can improve frequency utilization efficiency or throughput.
  • FIG. 20 is a flowchart showing an example of MCS determination processing according to the third embodiment of the present invention.
  • Step S501 The base station apparatus eNB determines MCS (referred to as first MCS). Thereafter, the process proceeds to step S502.
  • Step S502 The base station apparatus eNB calculates the duplication rate R i over in each mobile station apparatus UEi. Thereafter, the process proceeds to step S503.
  • Step S502 The base station apparatus eNB and the mobile station apparatus UEi determine an MCS (referred to as a second MCS) based on the duplication rate R i over calculated in Step S502.
  • FIG. 21 is a schematic block diagram illustrating an example of the configuration of the mobile station device UEi according to the present embodiment.
  • the MCS determination unit 11d is different.
  • the control information notified from the base station apparatus eNB from the control information receiving unit 109 is input to the MCS determining unit 11d.
  • the MCS determination unit 11d uses the MCS used by the own apparatus based on the information (also referred to as the first MCS index I i MCS ) indicating the MCS (also referred to as the first MCS) of the own apparatus included in the control information and the duplication rate information. To decide.
  • the MCS determination unit 11d outputs information indicating the coding rate corresponding to the determined MCS to the encoding unit 101, and outputs information indicating the modulation scheme corresponding to the determined MCS to the modulation unit 102.
  • the encoding unit 101 encodes the data bits at the coding rate indicated by the information input from the MCS determination unit 11d, and the modulation unit 102 modulates the code bits by the modulation scheme indicated by the information input from the MCS determination unit 11d. Apply.
  • FIG. 22 is a schematic block diagram illustrating an example of the configuration of the MCS determination unit 11d according to the present embodiment.
  • the MCS determination unit 11d includes a first MCS acquisition unit 111d, an MCS conversion information storage unit 112d, a code modulation setting unit 113d, an MCS value storage unit 114d, an overlap rate acquisition unit 115d, and a second MCS determination unit 116d. Is done.
  • the first MCS acquisition unit 111d acquires the first MCS index I i MCS included in the control information input from the control information reception unit 109.
  • the first MCS acquisition unit 111d outputs the acquired first MCS index I i MCS to the code modulation setting unit 113d and stores it in the MCS value storage unit 114d.
  • the MCS conversion information storage unit 112d stores a first MCS conversion table (FIG. 23) and a second MCS conversion table (FIG. 24).
  • the code modulation setting unit 113d is an MCS conversion information storage unit in the case of the orthogonal access method, that is, when the duplication rate Rover indicated by the duplication rate information input from the duplication rate acquisition unit 115 described later is “0”. Based on the first MCS conversion table stored in 112d, the first MCS index I i MCS input from the first MCS acquisition unit 111d is converted into a coding rate and a modulation scheme. In the case of the non-orthogonal access method, that is, when the duplication rate R over indicated by the duplication rate information input from the duplication rate acquisition unit 115 described later is not “0”, the code modulation setting unit 113d is an MCS conversion information storage unit.
  • a second MCS index (I i MCS -I i OVER ) input from a second MCS determination unit 116d described later is converted into a coding rate and a modulation scheme.
  • the code modulation setting unit 113d outputs information indicating the coding rate after conversion to the coding unit 101, and outputs information indicating the modulation scheme after conversion to the modulation unit 102.
  • the duplication rate acquisition unit 115 d acquires duplication rate information included in the control information input from the control information reception unit 109.
  • the duplication rate acquisition unit 115d outputs the obtained duplication rate information to the second MCS determination unit 116d and the code modulation setting unit 113d.
  • the second MCS determination unit 116d generates a correction value I i OVER of the first MCS index based on the overlap rate information input from the overlap rate acquisition unit 115d.
  • the second MCS determination unit 116d stores in advance correspondence information between the correction value I i OVER and the duplication rate information, and generates the correction value I i OVER based on the correspondence information.
  • the second MCS determination unit 116d generates the second MCS index by correcting the first index I i MCS stored in the MCS value storage unit 114d with the calculated correction value I i OVER .
  • the second MCS determination unit 116d calculates a second MCS index (I i MCS ⁇ I i OVER ) obtained by subtracting the correction value I i OVER from the first index I i MCS .
  • the second MCS determination unit 116d outputs the generated second MCS index (I i MCS -I i OVER ) to the code modulation setting unit 113d.
  • FIG. 23 is a schematic diagram illustrating an example of the first MCS conversion table according to the present embodiment.
  • the first MCS conversion table has columns of items of MCS index (Index), modulation multi-level number, and TBS index (Index).
  • the modulation multilevel number is associated with a modulation scheme
  • the TBS index is associated with a coding rate.
  • the MCS index “0” corresponds to the modulation multilevel number “2” and the TBS index “0”
  • the MCS index “1” includes the modulation multilevel number “2” and the TBS index “1”. It is supported.
  • the MCS index “10” is associated with the modulation multi-level number “4” and the TBS index “9”.
  • FIG. 23 shows that as the MCS index increases, the modulation multi-level number increases and the TBS index increases. That is, the MCS index is represented by an increase function of the modulation multi-level number and at least one increase function of the TBS index.
  • code modulation setting unit 113d by comparing the MCS index of the 1MCS index I i MCS and the 1MCS conversion table, converts the modulation level and TBS index, encode the first 1MCS index I i MCS Convert to rate and modulation scheme.
  • FIG. 24 is a schematic diagram illustrating an example of the second MCS conversion table according to the present embodiment.
  • the second MCS conversion table has columns of items of MCS index (Index), modulation multilevel number, and TBS index (Index).
  • FIG. 24 shows that as the MCS index increases, the modulation multi-level number increases and the TBS index increases. That is, the MCS index is represented by an increase function of the modulation multi-level number and at least one increase function of the TBS index.
  • the code modulation setting unit 113d compares the second MCS index (I i MCS -I i OVER ) with the MCS index of the second MCS conversion table, and converts the first MCS index into a modulation multi-level number and a TBS index. the (I i MCS -I i OVER) into a coding rate and modulation scheme.
  • the correction value I i OVER is an increasing function of the overlapping rate R over .
  • the 2MCS determining unit 116d a small MCS index higher overlap rate R-over-duplicate rate information indicates, that is, to determine the low multi-level number of a modulation scheme and coding rate.
  • the first MCS conversion table and the second MCS conversion table are the same table.
  • the present invention is not limited to this, and the first MCS conversion table and the second MCS conversion table are MCS indexes. Any one of the modulation multi-value number and the TBS index may be different.
  • FIG. 25 is a schematic block diagram illustrating an example of the configuration of the base station device eNB according to the present embodiment.
  • the base station apparatus eNB (FIG. 25) according to the present embodiment is compared with the base station apparatus eNB (FIG. 8) according to the first embodiment, the transmission rate determining unit 21d and the MCS setting unit 24d are different.
  • the functions of other components are the same as those of the first embodiment, description of the same functions as those of the first embodiment is omitted.
  • the transmission rate determining unit 21d determines the first MCS of each mobile station apparatus UEi based on the band allocation information and the propagation path characteristic information H i input from the allocation determining unit 205.
  • the transmission rate determining unit 21d controls, for each mobile station device UEi, the first MCS index I i MCS indicating the determined first MCS , the band allocation information input from the allocation determining unit 205, and the overlapping rate information indicating the overlapping rate.
  • the information is output to the information generation unit 206.
  • the MCS setting unit 24d performs the same processing as that of the second MCS determination unit 116d based on the first MCS index I i MCS and the overlap rate information input from the control information generation unit 206, so that each mobile station apparatus UEi
  • the second MCS to be used (the same as the MCS indicated by the second MCS index (I i MCS ⁇ I i OVER )) is determined.
  • the MCS setting unit 24d outputs information indicating the modulation scheme corresponding to the determined MCS of the mobile station apparatus UEi to the demodulation unit 226-i, and displays information indicating the coding rate corresponding to the determined MCS of the mobile station apparatus UEi.
  • the data is output to the decoding unit 227-i.
  • the demodulating unit 226-i performs demodulation based on the modulation scheme indicated by the information input from the MCS setting unit 24d, and the decoding unit 227-i converts data bits into data bits at the coding rate indicated by the information input from the MCS setting unit 24d. Decrypt.
  • FIG. 26 is a schematic block diagram illustrating an example of the configuration of the transmission rate determining unit 21d according to the present embodiment.
  • the transmission rate determination unit 21d includes an overlap rate calculation unit 210, an overlap rate information generation unit 210d, an equalized propagation path calculation unit 213d, a quality calculation unit 214, an MCS determination unit 215, and a transmission parameter output unit 216d. Consists of including.
  • the function which the duplication rate calculation part 210, the quality calculation part 214, and the MCS determination part 215 have is the same as 1st Embodiment, the description is abbreviate
  • the duplication rate information generation unit 210d generates duplication rate information indicating the duplication rate R i over input from the duplication rate calculation unit 210.
  • the duplication rate information generation unit 210d outputs the generated duplication rate information to the transmission parameter output unit 216d.
  • the post-equalization propagation path calculation unit 213d uses the equation (1) based on the band allocation information input from the assignment determination unit 205 and the post-equalization propagation path w i H i bar to calculate each mobile station apparatus UEi.
  • the equalized propagation path w i H i bar is calculated.
  • the post-equalization channel calculation unit 213d substitutes “1” for the residuals ⁇ i, j IUI and ⁇ i ISI in the equation (1).
  • the transmission parameter output unit 216d receives the band allocation information input from the duplication rate information generation unit 210d and the information (first MCS index I i MCS ) indicating the MCS (first MCS) of each mobile station apparatus UEi input from the MCS determination unit 215. ) And the bandwidth allocation information input from the allocation determination unit 205 is output to the control information generation unit 206.
  • the signal of this duplication rate information is arrange
  • FIG. 27 is a schematic block diagram showing an example of the configuration of the MCS setting unit 24d according to the present embodiment.
  • the MCS setting unit 24d includes a first MCS acquisition unit 241d, an MCS conversion information storage unit 242d, a code modulation setting unit 243d, an MCS value storage unit 244d, an overlap rate acquisition unit 245d, and a second MCS determination unit 246d. Is done.
  • the first MCS acquisition unit 241d acquires the first MCS index I i MCS of each mobile station apparatus UEi from the control information generation unit 206.
  • the first 1MCS index I i MCS is the same as the first 1MCS index I i MCS included in the control information notified to the mobile station device UEi from the base station apparatus eNB.
  • the first MCS acquisition unit 241d outputs the acquired first MCS index I i MCS to the code modulation setting unit 243d and stores it in the MCS value storage unit 244d.
  • the MCS conversion information storage unit 242d stores a first MCS conversion table (FIG. 23) and a second MCS conversion table (FIG. 24).
  • the code modulation setting unit 243d stores the MCS conversion information in the orthogonal access method, that is, when the duplication rate R i over indicated by the duplication rate information input from the duplication rate acquisition unit 245d described later is “0”. Based on the first MCS conversion table stored in the unit 242d, the first MCS index I i MCS input from the first MCS acquisition unit 241d is converted into a coding rate and a modulation scheme.
  • the code modulation setting unit 243d stores the MCS conversion information in the non-orthogonal access method, that is, when the duplication rate R i over indicated by the duplication rate information input from the duplication rate acquisition unit 245d described later is not “0” Based on the second MCS conversion table stored in the unit 242d, the second MCS index (I i MCS -I i OVER ) input from the second MCS determination unit 246d described later is converted into a coding rate and a modulation scheme.
  • the code modulation setting unit 243d outputs information indicating the coding rates of the converted mobile station apparatuses UE1 to UEI to the demodulation units 226-1 to 226-I and the replica generation units 228-1 to 228-I, respectively. .
  • the code modulation setting unit 113d outputs information indicating the modulation schemes of the converted mobile station apparatuses UE1 to UEI to the decoding units 227-1 to 227-I and the replica generation units 228-1 to 228-
  • the duplication rate acquisition unit 245d outputs the duplication rate information acquired from the control information generation unit 206 to the second MCS determination unit 246d and the code modulation setting unit 243d.
  • the second MCS determination unit 246d generates a correction value I i OVER for the first MCS index based on the overlap rate information input from the overlap rate acquisition unit 245d.
  • the second MCS determination unit 246d stores in advance correspondence information between the correction value I i OVER and the overlap rate information, and generates the correction value I i OVER based on the correspondence information. This correspondence information is the same as that of the mobile station apparatus UEi.
  • the second MCS determination unit 246d generates the second MCS index by correcting the first index I i MCS stored in the MCS value storage unit 244d with the calculated correction value I i OVER .
  • the second MCS determination unit 246d calculates a second MCS index (I i MCS ⁇ I i OVER ) obtained by subtracting the correction value I i OVER from the first index I i MCS .
  • the second MCS determination unit 246d outputs the generated second MCS index (I i MCS -I i OVER ) to the code modulation setting unit 243d.
  • the transmission rate determination unit 21d of the base station apparatus eNB determines the first MCS and generates control information including duplication rate information.
  • the MCS determination unit 11d of the mobile station device UEi and the MCS setting unit 24d of the base station device eNB determine the second MCS based on the first MCS and the overlap rate information determined by the transmission rate determination unit 21d.
  • the communication system considers the IUI and ISI more than necessary when determining the MCS, and sets the MCS with a low transmission rate, or the MCS with a high transmission rate that does not satisfy the required quality without considering the IUI and ISI.
  • the communication system can appropriately perform link adaptation even when using a non-orthogonal access scheme that uses iterative equalization for reception processing, and can improve frequency utilization efficiency or throughput.
  • the timing at which the first MCS acquisition units 111d and 241d acquire the first MCS index and the timing at which the duplication rate acquisition unit 241d acquires duplication rate information may be the same or different. May be.
  • the processing for the first MCS index and the duplication rate information performed by the transmission parameter output unit 216, the control information generation unit 206, and the control information transmission unit 207 may be processing at the same timing, or processing at different timings. It may be.
  • the timing at which the second MCS determination units 116d and 246d determine the second MCS may be immediately after the first MCS acquisition units 111d and 241d acquire the first MCS index, or the first MCS acquisition units 111d and 241d The timing for acquiring the first MCS index may be different.
  • FIG. 28 is a schematic diagram illustrating an example of the transmission timing of control information according to the present embodiment.
  • the vertical axis represents time (t).
  • the broken arrow represents control information including the first MCS index
  • the solid arrow represents control information including the overlapping rate information.
  • the control information may include both the first MCS index and the duplication rate information.
  • FIG. 28 shows that control information including duplication rate information can be transmitted at a timing that is more flexible than, for example, control information including the first MCS index.
  • arrows I11, I12, I13, and I14 indicate that control information including the first MCS index is transmitted from the mobile station apparatus eNB to the mobile station apparatus UE1.
  • Arrows I31, I32, and I33 indicate that control information including the first MCS index is transmitted from the mobile station apparatus eNB to the mobile station apparatus UE2.
  • Arrows I21, I22, I23, and I24 indicate that control information including duplication rate information is transmitted from the mobile station apparatus eNB to the mobile station apparatus UE1.
  • Arrows I41 and I42 indicate that control information including duplication rate information is transmitted from the mobile station apparatus eNB to the mobile station apparatus UE2.
  • the base station apparatus eNB connected to the mobile station apparatus UE1 starts or changes the band allocation of the mobile station apparatus UE2
  • transmission represented by arrows I31 and I21 is performed. That is, the arrow I31 indicates that control information including band allocation information and the first MCS is transmitted from the base station apparatus eNB to the mobile station apparatus UE2.
  • the arrow I21 indicates that the overlap rate R 1 over of the mobile station device UE1 changes due to the start or change of band allocation of the mobile station device UE2, and control information including this overlap rate R 1 over is transmitted from the base station device eNB to the mobile station device UE1. Indicates that it has been sent. In the case of FIG.
  • the duplication rate information can be notified to the mobile station apparatus UEi at a flexible timing.
  • the mobile station apparatus UEi can change MCS flexibly, and can improve a throughput, frequency utilization efficiency, or reception quality.
  • the transmission timing of duplication rate information may be a predetermined time interval, for example, a timer may be used.
  • this embodiment demonstrated the case where the base station apparatus eNB notifies the duplication rate information which shows duplication rate R i over to the mobile station apparatus UEi.
  • the overlap rate information if the information indicating the access method (overlap rate R i-over-is "0", “orthogonal access method”, if overlap rate R i-over-is not “0", “non-orthogonal access method )).
  • the present invention is not limited to this, and information indicating the access method from the base station device eNB to the mobile station device UEi (for example, “0” for the “orthogonal access method” and “non-orthogonal access method” An integer other than “0”, for example, “1”) may be used.
  • the base station apparatus eNB replaces with duplication rate information, and is 2nd MCS parameter
  • the mobile station apparatus UEi may notify the base station apparatus eNB of a second MCS index indicating the second MCS. In that case, the base station apparatus eNB may change the modulation scheme and the coding rate using the second MCS index notified by the MCS setting unit 24d.
  • the base station apparatus eNB sets the at least one of the removal residuals ⁇ i, j IUI and ⁇ i ISI to “1”, and then the equalized propagation path w i H
  • the present invention is not limited to this, and at least one of the removal residuals ⁇ i, j IUI and ⁇ i ISI may be a predetermined value, and is a value between “0” and “1”.
  • the base station apparatus eNB may set the removal residual ⁇ i, j IUI to “0.6”, the removal residual ⁇ i, j IUI to “0.6”, and the ⁇ i ISI to “0. 8 ”. Further, in the second and third embodiments and the second modification, the base station apparatus eNB determines the first MCS, and based on the first MCS, at least the removal residual ⁇ i, j IUI and the removal residual ⁇ i ISI The case of determining one has been described.
  • the present invention is not limited to this, and the base station apparatus eNB determines one of the modulation scheme and the coding rate, and the removal residual ⁇ i, j IUI and the removal residual based on one of the modulation scheme and the coding rate. At least one of the differences ⁇ i ISI may be determined.
  • a modulation system or a coding rate is determined based on duplication rate R i over. Also good. That is, the base station apparatus eNB determines at least one of the modulation scheme and the coding rate of the mobile station apparatus UEi based on the overlap rate R i over . Note that the base station apparatus eNB determines a modulation scheme with a lower multi-level number as the overlapping rate R i over is higher, and also determines a lower coding rate. Further, the base station apparatus eNB may determine a correction value for correcting the MCS, the modulation scheme, or the coding rate based on the overlapping rate R i over .
  • the base station apparatus eNB determines the maximum number of transport block bits received at a transmission rate (for example, TTI (Transmit Time Interval) or the maximum number of transport blocks) based on the overlap rate. (Number of bits) may be corrected or determined, or a value (for example, mobile station category) associated with the transmission rate may be corrected or determined.
  • TTI Transmit Time Interval
  • MCS Mobile Station Category
  • FIG. 29 is a flowchart showing an example of MCS determination processing according to the fourth embodiment of the present invention.
  • a transmission rate determination unit 21e described later performs this MCS determination process. Comparing the MCS determination process according to the present embodiment (FIG. 29) and the MCS determination process according to the second embodiment (FIG. 17), steps S302 to S303 are the same, and the process of step 601 before step S302 is performed. And the processing after step S604 after step S303 is different. Other processes (steps S302 to S303) are the same as those in FIG.
  • Step S601 The base station apparatus eNB estimates the propagation path characteristic information H i of each mobile station apparatus UEi, and determines the band allocation of the mobile station apparatuses UE1 to UEI from the estimated propagation path characteristic information H i . Thereafter, the process proceeds to step S302.
  • Step S604 The base station apparatus eNB performs turbo equalization (repetitive equalization) on the received signal from each mobile station based on the MCS and propagation path estimation value of all the mobile stations determined in step S303 or step S606 described later. The mutual information amount after the calculation is calculated. A method for calculating the mutual information amount will be described later. Thereafter, the process proceeds to step S605.
  • Step S605 The base station apparatus eNB determines whether or not the mutual information amount after turbo equalization for the received signals from all mobile stations calculated in step S604 is “1”. When all the mutual information amounts are “1”, the process proceeds to step S606, and when the mutual information amount means that the received signal of the mobile station cannot be demodulated correctly is smaller than “1”, the process proceeds to step S607.
  • the determination of whether or not the mutual information amount is smaller than “1” proceeds to step S607 even when only the reception signals of some mobile stations have the mutual information amount smaller than “1”.
  • the threshold for determining the mutual information amount is not limited to this example.
  • the process may proceed to step S606.
  • the mutual information amount threshold may be smaller than “1”. For example, the determination is made based on whether or not it is smaller than “0.95”.
  • Step S606 When the base station apparatus eNB determines that the received signals of all the mobile stations can be correctly detected based on the mutual information amount (S605-Yes), the MCS of all the mobile stations is stored, and the specific mobile station UE k Let MCS be “I k MCS +1”. This means that the MCS of a specific mobile station UE k is changed to an MCS with a high transmission rate.
  • the increase rate of the transmission rate of MCS is not limited to the above, and may be “I k MCS + m” where m is a natural number of 1 or more.
  • step S606 as a method of determining a specific mobile station UE k that changes the transmission rate to a high MCS, the mobile station that becomes “1” by the number of turbo equalization iterations with a smaller mutual information amount calculated in step S604.
  • a mobile station having a high E s / N 0 after equalization is preferentially set as UE k .
  • the UE k for changing the MCS does not need to be one mobile station, and the MCS of a plurality of mobile stations having the same priority may be changed to an MCS having a high transmission rate by the above UE k determination method. .
  • the MCSs of a plurality of mobile stations with higher priorities in the above UE k determination method may be changed to MCSs with higher transmission rates.
  • the process proceeds to step S604 again, and the mutual information amount when the updated MCS is used is calculated.
  • Step S607 When the base station apparatus eNB determines that at least a part of the reception signals of all the mobile stations cannot be correctly detected based on the mutual information amount (S605-No), the reception signals of all the mobile stations stored in Step S606 MCSs of all mobile stations determined to be detected correctly are acquired and output. Specifically, the latest MCS in which the mutual information amount after turbo equalization for the received signals from all mobile stations is “1” is acquired.
  • the base station apparatus eNB determines the MCS of all mobile stations acquired in step S607 to be the MCS that notifies the mobile station.
  • FIG. 30 is a flowchart illustrating an example of a mutual information amount calculation process in step S604.
  • the following steps S702 to S706 and S709 are performed for each mobile station.
  • Step S701 S indicating the number of times of turbo equalization is initialized to “1”.
  • Step S ⁇ b> 702 “1” is substituted into the ISI removal residual ⁇ i ISI and the IUI removal residual ⁇ i, j IUI .
  • Step S703 The base station apparatus eNB uses the propagation path characteristic information H i of each mobile station apparatus UEi, the removal residual ⁇ i ISI , ⁇ i, j IUI, and equation (1) to Calculate the propagation path gain.
  • the calculated channel gain after equalization is a value that takes into account ISI and IUI interference.
  • E s / N 0 after equalization is calculated using Equation (2), Equation (3), Equation (4), and Equation (5). calculate. Further, referring to the relationship between E s / N 0 after equalization for each modulation scheme (BPSK, QPSK, 16QAM, 64QAM) and the output mutual information (mutual information) shown in FIG. Calculate the output mutual information of the equalizer. That is, first, a graph indicating the relationship between E s / N 0 and the output mutual information amount of the equalizer is selected based on the modulation scheme indicated by the selected MCS.
  • FIG. 31 shows the mutual information calculated from the LLR after demodulation in the AWGN (Additive White Gaussian Noise) channel.
  • the mutual information amount can be calculated from E s / N 0 in this way by tabulating the characteristics for each modulation method shown in FIG. 31 or obtaining an approximate expression in advance.
  • Step S705 Based on the coding rate indicated by the MCS determined in step S303 or S606, an EXIT (Extrinsic Information Transfer) characteristic that is a relationship between the input mutual information amount and the output mutual information amount of the decoder is acquired.
  • the vertical axis represents the mutual information amount (mutual information (input)
  • the horizontal axis represents the mutual mutual information amount (mutual information (output)).
  • the EXIT characteristic depends not only on the coding rate but also on the coding method, in this embodiment, only the turbo code is used as the coding method, so the EXIT characteristic is selected based only on the coding rate. is doing.
  • the EXIT characteristic is stored for each combination of the encoding method and the encoding rate, and the combination of the encoding method and the encoding rate is stored. Based on the stored information, the EXIT characteristic may be selected.
  • These EXIT characteristics are obtained by tabulating or calculating approximate expressions in the same manner as in step S704, storing them in advance, and selecting them from them.
  • Step S706 The output mutual information amount of the decoder is calculated from the EXIT characteristic acquired in step S705 and the output mutual information amount of the equalizer calculated in step S704. Specifically, when the output mutual information amount of the equalizer is the input mutual information amount of the decoder, the output mutual information amount indicated by the EXIT characteristic is the output mutual information amount of the decoder. (Step S707) The number of turbo equalization iterations is incremented. (Step S708) It is determined whether or not the number of turbo equalization iterations exceeds the upper limit S MAX .
  • step S706 When processing is performed up to the upper limit of the number of times of turbo equalization, the output mutual information amount of each mobile station obtained in step S706 corresponds to the mutual information amount after turbo equalization in each mobile station. Therefore, output. On the other hand, if the number of times of turbo equalization is not the upper limit, the process proceeds to step S709.
  • Step S709 The LLR of the decoder output of each mobile station is calculated from the mutual information amount (decoder output mutual information amount) obtained in step S706.
  • the average power ⁇ 2 of noise is obtained for each mobile station from the mutual information amount I dec — out (mutual output information of the decoder) of each mobile station using the function of equation (14).
  • the LLR is calculated by the equation (16) from the average noise power ⁇ 2 based on the consistency condition.
  • n is an additive white Gaussian noise having an average of 0 and a variance ⁇ 2 .
  • s is a transmission signal
  • the base station cannot obtain a modulation signal to be received when determining the MCS. Therefore, a signal obtained by modulating the bit generated by the random number using the modulation method used in step S703 is used as s in Expression (16).
  • the ISI removal residual ⁇ i ISI and the IUI removal residual ⁇ i, j IUI are obtained using Equations (6) and (7). Proceeding to step S703, the equalized propagation path is calculated again using these removal residuals.
  • the base station apparatus eNB includes a transmission rate determining unit 21e instead of the transmission rate determining unit 21b of the base station apparatus eNB (FIG. 15) according to the second embodiment.
  • FIG. 33 is a schematic block diagram illustrating an example of the configuration of the transmission rate determining unit 21e according to the present embodiment.
  • the transmission rate determination unit 21e includes an equalized propagation path calculation unit 217b, a quality calculation unit 218b, a first MCS determination unit 219b, a mutual information amount calculation unit 254e, a signal detection determination unit 255e, a second MCS determination unit 256e, and a transmission parameter output unit. 216.
  • FIG. 1 is a transmission parameter output unit.
  • the transmission rate determining unit 21e receives the band allocation information and the propagation path estimation value from the allocation determining unit 205. Further, these pieces of information are input to the post-equalization propagation path calculation unit 217b and the mutual information amount calculation unit 254e. Band allocation information is also input to the transmission parameter output unit 216. Since the signal processing from the equalized propagation path calculation unit 217b to the first MCS determination unit 219b is the same as that of the second embodiment, the description thereof is omitted. The MCSs of all mobile stations UE determined by the first MCS determination unit 219b are input to the mutual information amount calculation unit 254e and the second MCS determination unit 256e.
  • the mutual information amount calculation unit 254e receives the bandwidth allocation information, the propagation path estimation value, and the MCS information I 1 MCS , I 2 MCS ,..., I I MCS of all mobile stations UE.
  • the mutual information amount calculation unit 254e calculates the mutual information amount after turbo equalization of the received signals of all mobile stations based on these pieces of information. That is, the mutual information amount calculation unit 254e performs the process of step S604 in FIG. Note that the MCS information I 1 MCS , I 2 MCS ,..., I I MCS is input from the first MCS determination unit 219b for the first iteration, and from the second MCS determination unit 256e for the second and subsequent times.
  • the signal detection determination unit 255e receives the mutual information amount after turbo equalization of the reception signals of all the mobile stations from the mutual information amount calculation unit 254e, and determines whether the reception signals from all the mobile stations can be detected correctly. Do. Whether or not the signal can be detected correctly is determined based on whether the mutual information amount is “1” or less than “1”. That is, the signal detection determination unit 255e performs the process of step S605 in FIG.
  • the second MCS determination unit 256e receives information from the signal detection determination unit 255e as to whether signals can be detected correctly with the combination of MCSs of all currently selected mobile stations. Furthermore, the second MCS determination unit 256e receives MCS information I 1 MCS , I 2 MCS ,..., I I MCS of all mobile stations from the first MCS determination unit 219b. If the signal detection determination unit 255e determines that the signal can be correctly detected by the combination of MCSs of all currently selected mobile stations, the second MCS determination unit 256e transmits the MCS of at least one mobile station UE k as a transmission rate. Change to a higher MCS. That is, the second MCS determination unit 256e performs the process of step S606 in FIG.
  • the second MCS determination unit 256e stores the changed MCS information I 1 MCS ′ , I 2 MCS ′ ,..., I I MCS ′ , and inputs it to the mutual information amount calculation unit 254e.
  • a mutual information amount based on the changed MCS information I 1 MCS ′ , I 2 MCS ′ ,..., I I MCS ′ is calculated by the mutual information amount calculation unit 254e, and signal detection obtained by the calculated mutual information amount The iterative process is performed such that the determination result as to whether or not can be correctly input is input from the signal detection determination unit 255e to the second MCS determination unit 256e.
  • the second MCS determination unit 256e stores the MCS information stored in the second MCS determination unit 256e. Is output to the transmission parameter output unit 216.
  • an example of the MCS information output by the second MCS determination unit 256e is MCS information that maximizes the sum of the throughputs of all the mobile stations among the MCS combinations of all the mobile stations that can correctly detect the signals of all the mobile stations. And so on. That is, the second MCS determination unit 256e also performs the processes of steps S607 and S608 in FIG. The processing of the transmission parameter output unit 216 is the same as that of the second embodiment.
  • FIG. 34 is a schematic block diagram showing an example of the configuration of the mutual information amount calculation unit 254e according to the present embodiment.
  • the mutual information calculation unit 254e includes an MCS information acquisition unit 260e, an equalized propagation path calculation unit 261e, a quality calculation unit 262e, an equalizer output mutual information calculation unit 263e, a decoder output mutual information calculation unit 264e, and a decoding A unit EXIT characteristic acquisition unit 265e and a removal residual calculation unit 266e are included.
  • the band allocation information and the channel estimation value are input to the post-equalization channel calculation unit 261e from the allocation determination unit 205, and the first MCS determination unit 219b or the second MCS determination unit is input to the MCS information acquisition unit 260e.
  • MCS information of all mobile stations is input from any one of 256e.
  • the MCS information acquisition unit 260e extracts modulation scheme information from the MCS information, inputs it to the equalizer output mutual information amount calculation unit 263e, extracts encoding rate information from the MCS information, and outputs a decoder EXIT characteristic acquisition unit. Input to 265e.
  • the quality calculation unit 262e calculates E s / N 0 after equalization using Equation (2), Equation (3), Equation (4), and Equation (5) from the channel gain after equalization.
  • the equalizer output mutual information amount calculation unit 263e calculates an output mutual information amount from the relationship between E s / N 0 after equalization for each modulation method in FIG. 31 and the output mutual information amount of the equalizer. That is, the quality calculation unit 262e performs the process of step 704 in FIG.
  • the decoder EXIT characteristic acquisition unit 265e acquires the EXIT characteristic of the decoder corresponding to the input coding rate, and outputs it to the decoder output mutual information calculation unit 264e.
  • the encoding method is also input to the decoder EXIT characteristic acquisition unit 265e, and the EXIT characteristic of the decoder determined by the encoding method and the encoding rate is output. That is, the decoder EXIT characteristic acquisition unit 265e performs the process of step S705 of FIG.
  • the decoder output mutual information amount calculation unit 264e receives the equalizer output mutual information amount calculated by the equalizer output mutual information amount calculation unit 263e and the EXIT characteristic acquired by the decoder EXIT characteristic acquisition unit 265e. Is done.
  • the decoder output mutual information amount calculation unit 264e refers to the EXIT characteristics and calculates the output mutual information amount of the decoder when the output mutual information amount of the equalizer is the input mutual information amount of the decoder.
  • the calculated output mutual information amount of decoding is input to the removal residual calculation unit 266e when the number of times of turbo equalization has not reached the upper limit.
  • the output mutual information amount of decoding is input to the signal detection determination unit 255e when the number of times of turbo equalization reaches the upper limit.
  • the decoder output mutual information calculation unit 264e performs the processing from steps S706 to S708 in FIG.
  • the removal residual calculation unit 266e calculates the LLR using the equations (14) and (15). Further, the removal residual calculation unit 266e calculates the ISI removal residual ⁇ i ISI and the IUI removal residual ⁇ i, j IUI from the calculated LLR using the equations (6) and (7). This is input to the post-equalization propagation path calculation unit 261e. That is, the removal residual calculation unit 266e performs the process of step S709 in FIG.
  • FIG. 35 and 36 show a case where the MCS is determined according to the present embodiment and a case where the IUI removal residual ⁇ i, j IUI is a fixed value (0.2, 0.4, 1.0) (FIG. 9, This is the throughput characteristic of FIG. FIG. 35 shows a case where the maximum duplication rate is 10%, and FIG. 36 shows a case where the maximum duplication rate is 30%.
  • the error correction code is a turbo code
  • the MCS is a case where the coding rate is selected from 1/3, 1/2, 2/3, 3/4 and the modulation method is selected from QPSK and 16QAM.
  • the IUI when the MCS is determined, the IUI is excessively evaluated to set the MCS with a low transmission rate (the number of information bits transmitted per unit frequency band), or the IUI is excessively evaluated to evaluate the bit error rate, etc.
  • An MCS with a high transmission rate that does not satisfy the required quality is not required, and an MCS with an appropriate transmission rate can be determined.
  • the degradation of the interference removal capability of turbo equalization by the modulation method can be reflected in the determination of MCS. Therefore, even when a non-orthogonal access method using repeated equalization is used for reception processing, link adaptation can be performed appropriately, and frequency utilization efficiency and throughput can be improved.
  • FIG. 37 is a schematic block diagram showing an example of the configuration of UEi according to this embodiment.
  • a clipping unit 810 is provided between the DFT unit 103 and the frequency mapping unit 104. Differences are added.
  • the functions of the other components reference numerals 101 to 109 are the same as those of the first and second embodiments, and thus the description of the same functions as those of the first and second embodiments is omitted.
  • the clipping unit 810 receives the frequency domain signal from the DFT unit 103, replaces a part of the frequency domain signal with zero, and outputs the result. This means that a part of the signal in the frequency domain (the part replaced with zero) is not transmitted.
  • the signal output from the clipping unit 810 is input to the frequency mapping unit 104.
  • FIG. 38 shows an example of the input signal and output signal of the clipping unit 810.
  • P23 is an input signal to the clipping unit 810
  • P24 is an output signal from the clipping unit 810.
  • the clipping unit 810 is a process of deleting some frequency domain signals.
  • a description is given assuming that the plurality of mobile stations UE1 to UEI are orthogonal access schemes, but the present invention is also applicable to non-orthogonal access schemes.
  • FIG. 39 is a schematic block diagram illustrating a configuration of the base station apparatus eNB according to the present embodiment.
  • the base station apparatus eNB includes an antenna 201, a reception processing unit 202, a reference signal separation unit 203, a propagation path estimation unit 204, an assignment determination unit 205, a control information generation unit 206, a control information transmission unit 207, an FFT unit 208, and a demapping unit.
  • the base station apparatus eNB includes a transmission rate determining unit 21f instead of the transmission rate determining unit 21 of the base station apparatus eNB (FIG. 8) according to the first embodiment. Further, clippings 820-1 to 820 -I are added between the DFT units 229-1 to 229 -I and the propagation path multiplication units 230-1 to 230 -I. However, the functions of other components (reference numerals 201 to 209, 222-1 to 230-1,..., 221-I to 230-I, 24d) are the same as those in the first and second embodiments. Description of the same functions as those in the first and second embodiments is omitted.
  • the clipping unit 820-i performs a process of setting a part of the signal in the frequency domain similar to the clipping unit of the mobile station apparatus UEi to zero on the signal input from the DFT unit 229-i, and a propagation path multiplying unit 230-i.
  • FIG. 40 is a schematic block diagram illustrating an example of the configuration of the transmission rate determining unit 21f according to the present embodiment.
  • the transmission rate determination unit 21f includes an equalized propagation path calculation unit 217b, a quality calculation unit 218b, a first MCS determination unit 219b, a mutual information amount calculation unit 254f, a signal detection determination unit 255e, a second MCS determination unit 256e, and a transmission parameter output unit. 216.
  • the transmission rate determination unit 21f according to the present embodiment is different from the transmission rate determination unit 21e (FIG. 33) according to the fourth embodiment in the mutual information amount calculation unit 254f.
  • the functions of other components are the same as those in the fourth embodiment, and thus the description of the same functions as those in the fourth embodiment is omitted.
  • FIG. 41 is a schematic block diagram showing an example of the configuration of the mutual information amount calculation unit 254f according to the present embodiment.
  • the mutual information calculation unit 254f includes an MCS information acquisition unit 260e, a post-equalization propagation path calculation unit 261f, a quality calculation unit 262e, an equalizer output mutual information calculation unit 263e, a decoder output mutual information calculation unit 264e, and a decoding A unit EXIT characteristic acquisition unit 265e and a removal residual calculation unit 266f.
  • the mutual information amount calculation unit 254f according to the present embodiment includes an equalized propagation path calculation unit 261f and a removal residual calculation unit 266f.
  • the functions of other components are the same as those in the fourth embodiment, and thus the description of the same functions as those in the fourth embodiment is omitted.
  • the post-equalization propagation path calculation unit 261f receives the removal residual ⁇ i ISI from the removal residual calculation unit 266f, and calculates the post-equalization propagation path gain using Equation (1).
  • the H i, j IUI bar is “0” because of the orthogonal access method, and the removal residual ⁇ i, j IUI is not input from the removal residual calculation unit 266f, but is processed as “0”.
  • the removal residual calculation unit 266f calculates the LLR using equations (14) and (15). Further, the removal residual calculation unit 266f calculates the ISI removal residual ⁇ i ISI from the calculated LLR using the equations (6) and (7), and inputs it to the post-equalization channel calculation unit 261f. .
  • the orthogonal access scheme has been described, but the present invention can also be applied to a non-orthogonal access scheme.
  • the transmission rate determination unit 21f has the same configuration as the transmission rate determination unit 21e of the fourth embodiment.
  • the present embodiment it is possible to prevent MCS having a low transmission rate by considering ISI more than necessary when determining MCS, or MCS having a high transmission rate that does not satisfy required quality without considering ISI.
  • the MCS of the transmission rate can be determined. Further, the degradation of the interference removal capability of turbo equalization by the modulation method can be reflected in the determination of MCS. Therefore, even when a non-orthogonal access method using repeated equalization is used for reception processing, link adaptation can be performed appropriately, and frequency utilization efficiency or throughput can be improved.
  • an overlapping bandwidth may be used instead of the overlapping rate.
  • the base station apparatus eNB determines a modulation scheme with a lower multi-level number as the overlapping bandwidth is wider, and also determines a lower coding rate.
  • a non-overlapping rate or a non-overlapping rate bandwidth may be used instead of the overlapping rate.
  • the base station apparatus eNB determines the modulation scheme having a higher multi-value number as the non-overlap ratio or non-overlap ratio bandwidth is wider, and also determines the higher coding rate.
  • the overlapping rate, non-overlapping rate, overlapping bandwidth, and non-overlapping bandwidth may be calculated for each predetermined frequency band (for example, system band, band, element carrier).
  • the frequency bandwidth may be represented by, for example, Hz (Hertz), or may be represented by the number of subcarriers or the number of resource blocks (N RB ).
  • Hz Hertz
  • N RB resource blocks
  • the base station apparatus eNB may perform a SIC (Successive Interference Cancellation) process.
  • the base station apparatus eNB uses the IUI residual table and the ISI residual table with different correspondences depending on the type of iterative equalization processing (turbo equalization, SIC, etc.), and uses the residual residual ⁇ i, j IUI , removal residual ⁇ i ISI , and MCS may be determined. Moreover, the base station apparatus eNB may correct the value of the removal residual ⁇ i, j IUI or ⁇ i ISI corresponding to the overlap rate R i over according to the type of iterative equalization processing.
  • the transmission rate determining unit 21,21a, 21b, 21c, 21d, 21e, 21f, MCS determination unit 11d, or remove residual MCS setting unit 24d has determined delta i, j IUI or delta i ISI May be input to the equalization units 223-1 to 223-I.
  • the equalization units 223-1 to 223-I use, for example, the removal residuals ⁇ i, j IUI and ⁇ i ISI input from the transmission rate determination units 21 and 21a at the first repetition of the turbo equalization process,
  • the weight w i may be calculated.
  • the equalization units 223-1 to 223-I for example, at the first repetition of the turbo equalization process, the transmission rate determination units 21, 21a, 21b, 21c, 21d, 21e, 21f, the MCS determination unit 11d, or the MCS using the weight w i for setting section 24d is calculated may be performed equalization process.
  • the base station apparatus eNB may determine MCS by processes other than said MCS determination process, when the zone
  • the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed.
  • the “computer system” here is a computer system built in the base station apparatus eNB or the mobile station apparatus UEi, and includes hardware such as an OS and peripheral devices.
  • the “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, and a hard disk incorporated in a computer system.
  • the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line,
  • a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time.
  • the program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
  • LSI Large Scale Integration
  • Each functional block of the base station apparatus eNB and the mobile station apparatus UEi may be individually made into a processor, or a part or all of them may be integrated into a processor.
  • the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.
  • the present invention can be applied to a wireless communication system of a mobile phone.
  • eNB base station device (receiving device) UE1 to UEI Mobile station device (transmitting device) DESCRIPTION OF SYMBOLS 201 Antenna 202 Reception processing part 203 Reference signal separation part 204 Propagation path estimation part 205 Assignment determination part 206 Control information generation part 207 Control information transmission part 208 FFT part 209 Demapping part T1 Repetitive equalization part 221-1 to 221-I Residual calculation unit 222-1 to 222-I Soft canceller unit 223-1 to 223-I Equalization unit 224-1 to 224-I IDFT unit 225-1 to 225-I Combining unit 226-1 to 226-I Demodulation Unit 227-1 to 227-I decoding unit 228-1 to 228-I replica generation unit 229-1 to 229-I DFT unit 230-1 to 230-I propagation path multiplication unit 231-1 to 231-I IUI extraction unit 24d MCS setting unit 21, 21a, 21b, 21c, 21d, 21e, 21f

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  • Mobile Radio Communication Systems (AREA)

Abstract

Dans la solution technique décrite dans la présente invention, un taux de codage et/ou un schéma de réglage d'un premier dispositif de transmission sont déterminés sur la base d'une bande de fréquences allouée au premier dispositif de transmission, et d'une bande de fréquences allouée à un ou plusieurs dispositifs parmi un ou plusieurs seconds dispositifs de transmission qui utilisent une bande de fréquences qui chevauche une partie de la bande de fréquences susmentionnée.
PCT/JP2012/070742 2011-08-26 2012-08-15 Dispositif de détermination de schéma de transmission, dispositif formant station de base, processeur, procédé de détermination de schéma de transmission, programme de détermination de schéma de transmission, et dispositif de transmission Ceased WO2013031538A1 (fr)

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JP2010147946A (ja) * 2008-12-19 2010-07-01 Nippon Telegr & Teleph Corp <Ntt> マルチキャリア無線通信システム及びマルチキャリア無線通信方法
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