WO2003085862A1 - Base station and communication system - Google Patents

Base station and communication system Download PDF

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Publication number
WO2003085862A1
WO2003085862A1 PCT/JP2002/003462 JP0203462W WO03085862A1 WO 2003085862 A1 WO2003085862 A1 WO 2003085862A1 JP 0203462 W JP0203462 W JP 0203462W WO 03085862 A1 WO03085862 A1 WO 03085862A1
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WO
WIPO (PCT)
Prior art keywords
modulation
value
base station
mobile station
sir
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Application number
PCT/JP2002/003462
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French (fr)
Japanese (ja)
Inventor
Jinsong Duan
Original Assignee
Mitsubishi Denki Kabushiki Kaisha
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Publication date
Application filed by Mitsubishi Denki Kabushiki Kaisha filed Critical Mitsubishi Denki Kabushiki Kaisha
Priority to PCT/JP2002/003462 priority Critical patent/WO2003085862A1/en
Publication of WO2003085862A1 publication Critical patent/WO2003085862A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
    • H04W52/267—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account the information rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/241—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo

Definitions

  • the present invention relates to a base station and a communication system that control a modulation and coding scheme and transmission power according to a measured quality value of a communication channel.
  • An adaptive modulation and coding scheme is used in a cellular mobile communication system, especially in a high-speed downstream bucket communication system (HSDPA: High SpeedDowlnlinkPacktEtAccess).
  • the adaptive modulation and coding scheme is a scheme in which a base station feedbacks the reception quality of a mobile station, and the base station adaptively switches the modulation scheme and coding rate based on the reception quality of the mobile station.
  • the mobile station When the mobile station receives the spread modulation signal transmitted from the base station, it measures the block error rate B LER of the spread modulation signal.
  • the mobile station determines a desired modulation and coding scheme MCS level with reference to a preset MCS (Modulation and Coding Scheme) list, and checks the level of the modulation and coding scheme MCS.
  • the information is transmitted to the base station as one feedback information.
  • the base station determines the modulation and coding scheme MCS to be used based on the feedback information.
  • the base station performs modulation and coding in accordance with the modulation and coding scheme MCS, and transmits a spread modulated signal to the mobile station with a default fixed transmission power.
  • an appropriate modulation and coding scheme MCS can be determined according to the block error rate BLER. Since the spread-spectrum modulated signal is transmitted to the mobile station with the default fixed transmission power, there has been a problem that the transmission power cannot be reduced.
  • the present invention has been made to solve the above problems, and has as its object to provide a base station and a communication system capable of reducing transmission power without lowering the maximum transmission rate. And Disclosure of the invention
  • a base station calculates a difference value between a quality measurement value received by a reception unit and a minimum necessary quality value in a modulation and coding method selected by a method selection unit, and calculates a difference value based on the difference value.
  • the transmission power of the spread modulation signal to be transmitted to the mobile station is controlled.
  • the transmission power can be reduced without lowering the maximum transmission speed.
  • a base station selects a modulation and coding scheme having the highest quality value among modulation and coding schemes satisfying a quality measurement value received by a receiving means.
  • a base station is configured to select a modulation and coding scheme with reference to a table indicating a correspondence between various modulation and coding schemes and quality values.
  • the base station calculates the transmission power offset from the difference value, subtracts the transmission power offset from the default fixed transmission power, and uses the subtraction result as the transmission power of the spread modulation signal. Things.
  • the base station according to the present invention has an effect of minimizing the transmission power.
  • the transmission power of the spread modulation signal is determined from the transmission power offset.
  • a modulation coding method is selected in consideration of the measured value.
  • the modulation means is selected by using the various types of quality measurement values.
  • the base station when the receiving means receives the SIR value and the block error rate as quality measurement values from the mobile station, selects a modulation and coding scheme according to the SIR value at the time of initial transmission or discontinuous transmission, During continuous transmission, the modulation and coding method is selected according to the block error rate.
  • the base station when the receiving means receives the number of multi-codes from the mobile station, the base station selects the modulation and coding method in consideration of the number of multi-codes.
  • the communication system upon receiving a quality measurement value from a mobile station, selects a modulation and coding scheme according to the quality measurement value, and selects the quality measurement value and the minimum necessary quality in the modulation and coding scheme.
  • a base station is provided which calculates a difference value with respect to the value and controls the transmission power of the spread modulation signal to be transmitted to the mobile station based on the difference value.
  • FIG. 1 is a configuration diagram showing a base station according to Embodiment 1 of the present invention.
  • FIG. 2 is a configuration diagram showing a mobile station according to Embodiment 1 of the present invention.
  • FIG. 3 is a flowchart showing transmission power control in the base station.
  • FIG. 4 is a flowchart showing quality measurement processing in the mobile station.
  • FIG. 5 is a graph showing BLER / SIR characteristics in each modulation and coding scheme MCS.
  • FIG. 6 is a conceptual diagram illustrating transmission power control.
  • FIG. 7 is an explanatory diagram showing a SIR table.
  • FIG. 8 is a conceptual diagram showing the relationship between the default fixed transmission power per bit and the transmission power offset.
  • FIG. 9 is a configuration diagram showing a base station according to Embodiment 3 of the present invention.
  • FIG. 10 is a block diagram showing a mobile station according to Embodiment 3 of the present invention.
  • FIG. 11 is a graph showing BLER / SIR characteristics for each moving speed.
  • FIG. 12 is an explanation showing an SIR table.
  • FIG. 13 is a configuration diagram showing the internal configuration of the measurement value receiving unit.
  • FIG. 14 is an explanatory diagram showing main channels in HSDPA.
  • FIG. 15 is a graph showing BLER / SIR characteristics for each number of multicodes. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 1 is a configuration diagram showing a base station according to Embodiment 1 of the present invention
  • 1 is a variable rate coding unit for inputting transmission information divided into a transport block, performing error correction on the transport block, and changing the coding rate of the transport block
  • 2 An interleaver that performs interleave processing on the transport park encoded by the variable-rate encoder 1, and 3 converts bit data that is output data of the interleaver 2 into symbol data.
  • the variable modulator 3 converts bit data into symbol data in accordance with a modulation and coding scheme (MCS) specified by the HSDPA transmission power controller 5. .
  • MCS modulation and coding scheme
  • An HSDPA transmission power control unit 6 to be controlled is an RF unit that converts a spread modulation signal output from the HSDPA transmission power control unit 5 into a radio frequency and outputs the converted signal to an antenna.
  • Reference numeral 11 denotes a measurement value reception unit (reception means) that receives an SIR value (referred to as I0r / Ioc value in 3GPP terminology) as a communication channel quality measurement value from the mobile station.
  • an SIR value referred to as I0r / Ioc value in 3GPP terminology
  • the present invention is not limited to this.
  • a C / I value or an SNR value may be received.
  • 1 2 is a required SIR value calculator for calculating a required SIR value of each modulation and coding scheme MCS when there are a plurality of selectable modulation and coding schemes MCS, 13 is received by the measurement value receiving section 11 SI IU direct and required SIR value calculator 1 JP02 / 03462
  • the MCS determining unit that selects the optimal modulation and coding system MCS by referring to the required SIR value of each modulation and coding system MCS calculated by 2 and 14 is the modulation selected by the MCS determining unit 13
  • An AMCS scheduler that, upon receiving the coding scheme MCS, finally determines the modulation coding scheme MCS in consideration of the packet communication requests of all mobile stations and the resource status of the base station.
  • the required SIR value calculation unit 12, the MCS determination unit 13 and the AMCS scheduler 14 constitute a method selection unit.
  • SIR offset calculator 15 estimates the minimum required quality value SIR min in the modulation and coding scheme MCS finally determined by the AMC scheduler 14 and compares the SIR value received by the measurement value reception unit 11 with the SII value.
  • Minimum required quality value SIR offset calculator that calculates the difference from SIR min (hereinafter referred to as SIR offset), and 16 is the SIR offset calculated by SIR offset calculator 15
  • the transmission power control unit calculates the transmission power offset, subtracts the transmission power offset from the default fixed transmission output, and uses the result of the subtraction as the transmission power of the spread modulation signal. It should be noted that the SIR offset calculation section 15 and the transmission power control section 16 constitute a power control means.
  • FIG. 2 is a configuration diagram showing a mobile station according to Embodiment 1 of the present invention.
  • reference numeral 21 denotes a despreading device for despreading a spread modulation signal with a code number and a code number included in downlink signaling.
  • a demodulation unit 22 for converting the symbol data output from the despreading unit 21 into a bit data, and 23 a bit data output from the demodulation unit 22.
  • a din evening reaver that performs a din evening reeve process for the evening, and a variable rate 24 that decodes a transport protocol that is bit data output from the din evening 23 It is a decoding unit.
  • 25 is a CPICH receiving unit that receives the common pilot channel CPICH
  • 26 is a common pilot channel received by the CPICH receiving unit 25
  • SIR value measurement unit that calculates the SIR value of the channel destined for itself by referring to the information on the CPI CH and the dedicated data channel power allocation and spreading factor addressed to itself.27 is the SIR calculated by the SIR value measurement unit 26. This is a feedback transmission unit that transmits the value to the base station.
  • FIG. 3 is a flowchart showing transmission power control in the base station
  • FIG. 4 is a flowchart showing quality measurement processing in the mobile station. Next, the operation will be described.
  • the modulation and coding scheme MCS with a high modulation index and coding rate has a high transmission rate, but requires a higher SIR value.
  • FIG. 5 is a graph showing BLE RZS IR characteristics in each modulation and coding scheme MCS.
  • BLER th is a threshold of a block error rate indicating a predetermined communication quality
  • a to F are thresholds of BLER. This is the required SIR value of the modulation coding scheme MCS (1) to (6) that satisfies th .
  • variable rate coding unit 1 When the transmission information divided into the transport blocks is input, the variable rate coding unit 1 performs error correction on the transport block and changes the coding rate of the transport block.
  • the coding rate of the transport block is given from the AMS scheduler 14.
  • the in-band reaver 2 Upon receiving the encoded transport block from the variable rate encoding unit 1, the in-band reaver 2 performs the in-loop processing on the transport block.
  • the in-night and leave processing is performed for each channel, but the in-and-out leave processing is performed, for example, when there is a memory having a row and an X-column configuration, data write processing to the memory is performed. While reading is performed in the column direction, data reading processing is performed in the row direction. By performing the overnight reeve processing, it is possible to mitigate the long-term continuation of the level decrease caused by Doppler peculiar to mobile communication.
  • variable modulator 3 converts the bit data that is the output data of the interleaver 2 into the symbol data. That is, the variable modulator 3 converts the bit data into symbol data according to the modulation and coding scheme MCS indicated by the AMS scheduler 14. Examples of the modulation scheme defined in the modulation and coding scheme MCS include QPSK, 16QAM, and 64QAM.
  • the spreading modulator 4 Upon receiving the symbol data from the variable modulator 3, the spreading modulator 4 spread-modulates the symbol data with the channelization code number and the number of codes given from the AMS scheduler 14. For example, if the number of codes is 5, spread modulation of symbol data is performed using five channelization codes.
  • the HSDPA transmission power control unit 5 When the HSDPA transmission power control unit 5 receives a spread modulation signal from the spread modulation unit 4 in order to reduce the transmission power without reducing the maximum transmission rate, the HSDPA transmission power control unit 5 appropriately adjusts the transmission power of the spread modulation signal. Control.
  • the measurement value reception unit 11 of the HSDPA transmission power control unit 5 receives the SIR value (step ST1). The process of measuring the SIR value at the mobile station will be described later.
  • FIG. 7 is an explanatory diagram showing an SIR table for storing a required SIR value, which is a calculation result of the required SIR value calculation unit 12.
  • the MCS determining section 13 refers to the SIR table in FIG. 7 and selects one of the modulation and coding schemes that can satisfy the required SIR value. The one with the largest SIR value is selected (step ST2).
  • the MCS levels are arranged in ascending order of information rate. The higher the MCS level, the higher the information rate and the higher the required SIR value.
  • the AMCS scheduler 14 Upon receiving the modulation and coding scheme MCS selected by the MCS deciding unit 13, the AMCS scheduler 14 takes into account the packet communication requests of all mobile stations and the resource status of the base station, and modulates the coding scheme. Finalize MCS.
  • the AMCS scheduler 14 outputs the coding rate defined in the modulation coding scheme MCS to the variable rate coding section 1, outputs the modulation scheme to the variable modulation section 3, and sets the channelization code number.
  • ⁇ Output the number of codes to spreading modulator 4.
  • the SIR offset calculator 15 estimates the minimum required quality value SIR min in the modulation and coding scheme MCS (see FIG. 6). ). For example, the minimum required quality value SIR min is calculated by multiplying the required S value of the modulation and coding scheme MCS by a predetermined coefficient.
  • the SIR value received by the measurement value The difference from the quality value SIR min is calculated as an SIR offset (step ST3).
  • the SIR offset may be calculated in consideration of a predetermined SIR margin.
  • SIR offset ⁇ h SIR value-SIR min -SIR margin
  • the transmission power controller 16 calculates the SIR offset by the SIR offset calculator 15. Since it is proportional, for example, as shown below, the transmission power offset is calculated from the SIR offset (step ST4).
  • the transmission power offset is subtracted from the default fixed transmission power, and the subtraction result is determined as the transmission power of the spread modulation signal (step ST5).
  • Transmission power Default fixed transmission power ⁇ Transmission power offset
  • FIG. 8 is a conceptual diagram showing the relationship between default fixed transmission power and transmission power offset per bit. '
  • the RF section 6 converts the spread modulation signal to a radio frequency and outputs it to the antenna, thereby converting the spread modulation signal. Send to mobile station.
  • the spread modulation signal is applied to despreading section 21 after radio frequency conversion is performed.
  • the despreading unit 21 despreads the spread modulation signal with the code number and the code number included in the downlink signaling, and outputs a symbol data.
  • the demodulation unit 22 Upon receiving the symbol data from the despreading unit 21, the demodulation unit 22 receives it in advance.
  • the received modulation and coding scheme MCS converts the symbol data into bit data.
  • the deinterleaver 23 Upon receiving the bit data from the demodulation unit 22, the deinterleaver 23 performs an interleave process on the bit data.
  • Din Yu The Din Yi Reeve processing of Lever 23 is the reverse processing of the InterLino's 2 In Yi Reeve processing.
  • variable rate decoding unit 24 Upon receiving the transport block, which is bit data, from the digital receiver 23, the variable rate decoding unit 24 decodes the transport block.
  • the CP I CH receiving section 25 receives the common pilot channel CP I CH (step ST 11).
  • the SIR value measuring unit 26 refers to the common pilot channel CP ICH and the dedicated data of the individual data channel power allocation and spreading factor addressed to itself. To calculate the SIR value of the channel addressed to itself (step ST12) o
  • the feedback transmission unit 27 transmits the SIR value to the base station (step ST13).
  • the HSDPA transmission power control unit 5 when the HSDPA transmission power control unit 5 receives the SIR value, it selects the modulation and coding scheme MCS according to the SIR value, and selects the SIR value.
  • SIR offset which is the difference value between the required minimum quality value SIR min and the modulation and coding scheme MCS, is calculated, and based on the SIR offset, the spread modulation signal output from the spread modulator 4 is calculated. Since the transmission power is controlled, the transmission power can be reduced without lowering the maximum transmission speed.
  • the mobile station calculates the SIR value and transmits it to the base station has been described.
  • the mobile station holds the SIR table as shown in FIG.
  • the modulation and coding scheme MCS may be selected, and the selection information of the modulation and coding scheme MCS may be transmitted to the base station.
  • the measured value receiving section 11 of the base station receives the selection information of the modulation and coding scheme MCS instead of the SIR value from the mobile station. Select an encoding method. This has the effect of reducing the processing load on the base station. Further, the mobile station may calculate the SIR offset in the same manner as the SIR offset calculation unit 15 of the base station, and transmit the SIR offset to the base station.
  • measured value receiving section 11 of the base station receives the SIR offset and outputs the SIR offset to transmission power control section 16. This has an effect that the SIR offset calculator 15 of the base station can be omitted.
  • FIG. 9 is a block diagram showing a base station according to Embodiment 3 of the present invention.
  • the same reference numerals as in FIG. 1 denote the same or corresponding parts, and a description thereof will be omitted.
  • 3 1 is a measurement value receiving unit (reception means) that receives the SIR value from the mobile station and also receives the moving speed or Doppler frequency of the mobile station.
  • 3 2 is when there are multiple selectable modulation and coding schemes MCS.
  • the required SIR value of each modulation and coding scheme The required SIR value calculation unit that calculates the SIR value and the moving speed or the Doppler frequency received by the measurement value reception unit 31 and each modulation and coding scheme calculated by the required SIR value calculation unit 32
  • An MCS determination unit that selects the optimal modulation and coding scheme MCS by referring to the required SIR value of the MCS.
  • the required SIR value calculation unit 32 and the MCS determination unit 33 constitute a method selection means.
  • SIR min in the MCS is estimated, and the SIR value received by the measurement value receiving unit 3 1 and the minimum required quality value
  • SIR offset calculator power control means
  • FIG. 10 is a block diagram showing a mobile station according to Embodiment 3 of the present invention.
  • the same reference numerals as in FIG. 2 denote the same or corresponding parts, and a description thereof will be omitted.
  • 4 1 is a mobile measuring unit for measuring the moving speed or Doppler frequency of the mobile station
  • 4 2 is the SIR value calculated by the SIR value measuring unit 26 and the moving speed or Doppler frequency measured by the mobile measuring unit 41 Is transmitted to the base station.
  • the mobile station mobile measurement unit 41 selects the modulation and coding scheme MCS without considering changes in the mobile station's mobile speed and Doppler frequency. Measures the speed or Doppler frequency, and the feedback transmitter 42 of the mobile station compares the SIR value calculated by the SIR value measuring section 26 with the moving speed or Doppler frequency measured by the mobile measuring section 41 to the base station. , The base station may select the modulation and coding scheme in consideration of the moving speed of the mobile station or the Doppler frequency.
  • the required SIR value calculation unit 32 of the base station changes the BLER / SIR characteristic in the modulation and coding scheme MCS when the moving speed of the mobile station and the frequency of the docker are different (see FIG. 11).
  • the modulation and coding schemes MCS (1) to Calculate the required SIR value of (6).
  • FIG. 12 is an explanatory diagram showing an SIR table for storing a required SIR value calculated by the required SIR value calculation unit 32.
  • the MCS determination unit 33 refers to the SIR table in Fig. 12 and modulates the signal to satisfy the SIR value. Search for at least one coding method MCS, and select the modulation coding method MCS with the highest quality value from among them.
  • the modulation coding method MCS (4) having the highest quality value is selected from the modulation coding methods MCS (1), (2), (3), and (4).
  • the SIR offset calculator 34 estimates the minimum necessary quality value SIR min in the modulation and coding scheme MCS.
  • the modulation and coding scheme MCS (4) the modulation and coding scheme MCS (4)
  • the required minimum quality value SIR min is calculated by multiplying the required SIR value of D2 by a predetermined coefficient.
  • the modulation and coding scheme MCS is selected in consideration of the measured value. Therefore, even when the mobile station is moving, it is possible to select an appropriate modulation and coding scheme MCS and perform transmission power control, and as a result, it is possible to increase the communication capacity. Play.
  • the MCS determination unit 33 based on the SIR value
  • the base station receives a bit error rate BLER instead of an SIR value as a communication channel quality measurement value, for example, if a BLER table equivalent to the SIR table is prepared, modulation from the bit error rate BLER will be performed. Coding method MCS can be selected.
  • the bit error rate BLER has an advantage that it is not necessary to prepare a BLER table for each moving speed because the moving speed of the mobile station and the Fading environment element have been considered.
  • the modulation and coding scheme MCS may be selected based on the bit error rate BLER.
  • the measured value receiving section 11 of the base station receives the SIR value and the bit error rate BLER from the mobile station, and uses the SIR value or the bit error rate BLER as necessary. To select the modulation and coding scheme MCS.
  • the measurement value receiving section 11 incorporates a transmission status determination section 51 and a switching section 52 as shown in FIG. 13, and the transmission status determination section 51 initializes the transmission status at the base station. Judge whether it is during transmission, discontinuous transmission, or continuous transmission.
  • the switching unit 52 outputs the SIR value received from the mobile station to the MCS determination unit 13 and the like, and the Selects modulation and coding scheme MCS based on SIR value, and controls transmission power.
  • the transmission status determination unit 51 determines that continuous transmission is being performed, the bit error rate BLER received from the mobile station is output to the MCS determination unit 13 and the like, and the bit error rate is output. Selects modulation coding scheme MCS based on BL ER and controls transmission power.
  • the SIR measuring section 26 of the mobile station measures the bit rate B BLE in addition to measuring the SIR value. That is, the common pilot channel CPI CH, the associated HS-SC CH channel (a channel for notifying the mobile station of information such as the MCS level in advance), or the HS-DSCH channel to the mobile station itself (individual packet data addressed to the mobile station).
  • the feedback transmitter 27 measures the bit error rate BLER of the overnight channel) and sends the SIR value and bit error rate BLER to the base station.
  • FIG. 14 is an explanatory diagram showing main channels in HSDPA. According to the fourth embodiment, there is an effect that communication can be continued even if the transmission status changes.
  • Embodiment 5
  • Embodiments 1 to 4 although not particularly mentioned, if the number of multicodes is different, as shown in FIG. 15, the BLER / SIR characteristic in the modulation and coding scheme MCS changes.
  • the mobile station when the mobile station transmits the SIR value, a desired number of multi-codes is transmitted to the base station from the viewpoint of reducing intra-cell interference.
  • the MCS determination unit 13 When the measured value receiving unit 11 receives the SIR value and the desired number of multicodes from the mobile station, the MCS determination unit 13 considers the desired number of multicodes and modulates the modulation code from the SIR value. Select MCS. The required S I IU direct calculation unit 12 generates an S I R table for each multicode number in advance.
  • the base station transmits with the desired number of multi-codes of the mobile station, thereby achieving an effect of reducing intra-cell interference.
  • the base station feeds back the reception quality of the mobile station, and the base station performs the feedback based on the reception quality of the mobile station. It is suitable for adopting a method of adaptively switching the modulation method and the coding rate based on this.

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Abstract

Upon receiving an SIR value, an HSDPA transmission power control section (5) selects a modulation coding system MCS depending on that SIR value and calculates an SIR offset, i.e. the difference between that SIR value and a minimum necessary quality value SIRmin in that modulation coding system MCS, and then controls transmission power of a spread modulation signal being outputted from a spread modulating section (4) based on that SIR value. Transmission power can be reduced without lowering the maximum transmission rate.

Description

明 細 書 基地局及び通信システム 技 分野  Description Base station and communication system
この発明は、 通信路の品質測定値に応じて変調符号化方式及び送信電 力を制御する基地局及び通信システムに関するものである。 背景技術  The present invention relates to a base station and a communication system that control a modulation and coding scheme and transmission power according to a measured quality value of a communication channel. Background art
セルラー方式の移動体通信システム、 特に高速下りバケツ ト通信シス テム （H S D P A : H i g h S p e e d D o wn l i n k P a c k e t A c c e s s ) では適応変調符号化方式が用いられている。 適応変調符号化方式とは、 基地局が移動局の受信品質をフィ一ドバツ クし、 基地局が移動局の受信品質に基づいて変調方式や符号化レートを 適応的に切り替える方式である。  An adaptive modulation and coding scheme is used in a cellular mobile communication system, especially in a high-speed downstream bucket communication system (HSDPA: High SpeedDowlnlinkPacktEtAccess). The adaptive modulation and coding scheme is a scheme in which a base station feedbacks the reception quality of a mobile station, and the base station adaptively switches the modulation scheme and coding rate based on the reception quality of the mobile station.
従来の通信システムは、 例えば 「 N o k i a， : U L s i g n a l i n g f o r T F R C s e l e c t i o n , 3 G P P W G 1 H S D P A a d o c m e e t i n g , R l 0 1 - 1 0 2 4 , N o v e mb e r , 2 0 0 1」 に開示されている 従来の通信システム の具体的内容は次の通りである。 Conventional communication systems, for example, "N okia,: UL signalingfor TFRC selection , 3 GPPWG 1 HSDPA adocmeeting, R l 0 1 - 1 0 2 4, N ove mb er, 2 0 0 1 " in the prior art as disclosed in The specific contents of the communication system are as follows.
移動局は、 基地局から送信された拡散変調信号を受信すると、 その拡 散変調信号のプロヅクエラーレート B L E Rを測定する。  When the mobile station receives the spread modulation signal transmitted from the base station, it measures the block error rate B LER of the spread modulation signal.
そして、 移動局は、 予め設定されている M C S (M o d u l a t i o n a n d C o d i n S c h e m e ) リス トを参照して、 所望の 変調符号化方式 M C Sのレベルを決定し、 その変調符号化方式 M C Sの レベルをフィ一ドバック情報として基地局に送信する。 基地局は、 移動局からフィードバック情報を受信すると、 そのフィー ドバヅク情報に基づいて、 使用する変調符号化方式 M C Sを決定する。 そして、 基地局は、 その変調符号化方式 M C Sにしたがって変調符号 化を実施し、 デフオルトの固定送信電力で拡散変調信号を移動局に送信 する。 Then, the mobile station determines a desired modulation and coding scheme MCS level with reference to a preset MCS (Modulation and Coding Scheme) list, and checks the level of the modulation and coding scheme MCS. The information is transmitted to the base station as one feedback information. Upon receiving the feedback information from the mobile station, the base station determines the modulation and coding scheme MCS to be used based on the feedback information. Then, the base station performs modulation and coding in accordance with the modulation and coding scheme MCS, and transmits a spread modulated signal to the mobile station with a default fixed transmission power.
従来の通信システムは以上のように構成されているので、 ブロックェ ラーレート B L E Rに応じて適正な変調符号化方式 M C Sを決定するこ とができるが、 いずれの変調符号化方式 M C Sを決定しても、 デフオル トの固定送信電力で拡散変調信号を移動局に送信するため、 送信電力の 小電力化を図ることができないなどの課題があつた。  Since the conventional communication system is configured as described above, an appropriate modulation and coding scheme MCS can be determined according to the block error rate BLER. Since the spread-spectrum modulated signal is transmitted to the mobile station with the default fixed transmission power, there has been a problem that the transmission power cannot be reduced.
この発明は上記のような課題を解決するためになされたもので、 最大 伝送速度の低下を招く ことなく、 送信電力の小電力化を図ることができ る基地局及び通信システムを得ることを目的とする。 発明の開示  The present invention has been made to solve the above problems, and has as its object to provide a base station and a communication system capable of reducing transmission power without lowering the maximum transmission rate. And Disclosure of the invention
この発明に係る基地局は、 受信手段により受信された品質測定値と方 式選択手段により選択された変調符号化方式における必要最小限の品質 値との差分値を計算し、 その差分値に基づいて移動局に送信する拡散変 調信号の送信電力を制御するようにしたものである。  A base station according to the present invention calculates a difference value between a quality measurement value received by a reception unit and a minimum necessary quality value in a modulation and coding method selected by a method selection unit, and calculates a difference value based on the difference value. Thus, the transmission power of the spread modulation signal to be transmitted to the mobile station is controlled.
このことによって、 最大伝送速度の低下を招く ことなく、 送信電力の 小電力化を図ることができる効果がある。  As a result, the transmission power can be reduced without lowering the maximum transmission speed.
この発明に係る基地局は、 受信手段により受信された品質測定値を満 足する変調符号化方式の中で、 品質値が最高の変調符号化方式を選択す るようにしたものである。  A base station according to the present invention selects a modulation and coding scheme having the highest quality value among modulation and coding schemes satisfying a quality measurement value received by a receiving means.
このことによって、 最大伝送速度の低下を防止することができる効果 がある。 この発明に係る基地局は、 各種の変調符号化方式と品質値の対応関係 を示すテーブルを参照して変調符号化方式を選択するようにしたもので ある。 This has the effect of preventing a decrease in the maximum transmission rate. A base station according to the present invention is configured to select a modulation and coding scheme with reference to a table indicating a correspondence between various modulation and coding schemes and quality values.
このことによって、 構成の複雑化を招く ことなく、 最適な変調符号化 方式を選択することができる効果がある。  This has an effect that an optimal modulation and coding scheme can be selected without causing a complicated configuration.
この発明に係る基地局は、 差分値から送信電力オフセッ トを計算して 、 デフォルトの固定送信電力から送信電力オフセッ トを減算し、 その減 算結果を拡散変調信号の送信電力とするようにしたものである。  The base station according to the present invention calculates the transmission power offset from the difference value, subtracts the transmission power offset from the default fixed transmission power, and uses the subtraction result as the transmission power of the spread modulation signal. Things.
このことによって、 送信電力の最小化を図ることができる効果がある この発明に係る基地局は、 受信手段が移動局から通信路の品質測定値 を受信する代わりに、 その移動局から変調符号化方式の選択情報を受信 すると、 その選択情報が示す変調符号化方式を選択するようにしたもの である。  As a result, the base station according to the present invention has an effect of minimizing the transmission power. When the selection information of the scheme is received, the modulation and coding scheme indicated by the selection information is selected.
このことによって、 基地局の処理負担を軽減することができる効果が める。  This has the effect of reducing the processing load on the base station.
この発明に係る基地局は、 受信手段が移動局から送信電力オフセッ ト を受信すると、 その送信電力オフセッ 卜から拡散変調信号の送信電力を 決定するようにしたものである。  In the base station according to the present invention, when the receiving means receives the transmission power offset from the mobile station, the transmission power of the spread modulation signal is determined from the transmission power offset.
このことによって、 基地局の処理負担を軽減することができる効果が める。  This has the effect of reducing the processing load on the base station.
この発明に係る基地局は、 受信手段が移動局から移動速度又は ドップ ラー周波数の測定値を受信すると、 その測定値を考慮して変調符号化方 式を選択するようにしたものである。  In a base station according to the present invention, when a receiving means receives a measured value of a moving speed or a Doppler frequency from a mobile station, a modulation coding method is selected in consideration of the measured value.
このことによって、 移動局が移動中であっても最適な変調符号化方式 を選択して送信電力制御を実施することができるようになり、 その結果 、 通信容量を増加することができる効果がある。 As a result, even when the mobile station is moving, it is possible to select an optimal modulation and coding scheme and perform transmission power control. As a result, There is an effect that the communication capacity can be increased.
この発明に係る基地局は、 受信手段が移動局から複数種類の品質測定 値を受信すると、 各種の品質測定値を使い分けて変調符号化方式を選択 するようにしたものである。  In the base station according to the present invention, when the receiving means receives a plurality of types of quality measurement values from the mobile station, the modulation means is selected by using the various types of quality measurement values.
このことによって、 送信状況が変化しても通信を継続することができ る効果がある。  This has the effect that communication can be continued even if the transmission status changes.
この発明に係る基地局は、 受信手段が移動局から品質測定値として S I R値とブロックエラーレートを受信すると、 初期送信時又は不連続送 信時には S I R値に応じて変調符号化方式を選択し、 連続送信時にはブ ロックエラーレートに応じて変調符号化方式を選択するようにしたもの である。  The base station according to the present invention, when the receiving means receives the SIR value and the block error rate as quality measurement values from the mobile station, selects a modulation and coding scheme according to the SIR value at the time of initial transmission or discontinuous transmission, During continuous transmission, the modulation and coding method is selected according to the block error rate.
このことによって、 送信状況が変化しても通信を継続することができ る効果がある。  This has the effect that communication can be continued even if the transmission status changes.
この発明に係る基地局は、 受信手段が移動局からマルチコ一ド数を受 信すると、 そのマルチコ一ド数を考慮して変調符号化方式を選択するよ うにしたものである。  In the base station according to the present invention, when the receiving means receives the number of multi-codes from the mobile station, the base station selects the modulation and coding method in consideration of the number of multi-codes.
このことによって、 セル内干渉を減少することができる効果がある。 この発明に係る通信システムは、 移動局から品質測定値を受信する と 、 その品質測定値に応じて変調符号化方式を選択し、 その品質測定値と 当該変調符号化方式における必要最小限の品質値との差分値を計算し、 その差分値に基づいて移動局に送信する拡散変調信号の送信電力を制御 する基地局を設けたものである。  This has the effect of reducing intra-cell interference. The communication system according to the present invention, upon receiving a quality measurement value from a mobile station, selects a modulation and coding scheme according to the quality measurement value, and selects the quality measurement value and the minimum necessary quality in the modulation and coding scheme. A base station is provided which calculates a difference value with respect to the value and controls the transmission power of the spread modulation signal to be transmitted to the mobile station based on the difference value.
このことによって、 最大伝送速度の低下を招く ことなく、 送信電力の 小電力化を図ることができる効果がある。 図面の簡単な説明 第 1図はこの発明の実施の形態 1による基地局を示す構成図である。 第 2図はこの発明の実施の形態 1による移動局を示す構成図である。 第 3図は基地局における送信電力制御を示すフローチヤ一トである。 第 4図は移動局における品質測定処理を示すフローチャートである。 第 5図は各変調符号化方式 M C Sにおける B L E R / S I R特性を示 すグラフ図である。 As a result, the transmission power can be reduced without lowering the maximum transmission speed. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a configuration diagram showing a base station according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram showing a mobile station according to Embodiment 1 of the present invention. FIG. 3 is a flowchart showing transmission power control in the base station. FIG. 4 is a flowchart showing quality measurement processing in the mobile station. FIG. 5 is a graph showing BLER / SIR characteristics in each modulation and coding scheme MCS.
第 6図は送信電力制御を説明する概念図である。  FIG. 6 is a conceptual diagram illustrating transmission power control.
第 7図は S I Rテーブルを示す説明図である。  FIG. 7 is an explanatory diagram showing a SIR table.
第 8図は 1 ビッ ト当りのデフオルトの固定送信電力と送信電力オフセ ッ トの関係を示す概念図である。  FIG. 8 is a conceptual diagram showing the relationship between the default fixed transmission power per bit and the transmission power offset.
第 9図はこの発明の実施の形態 3による基地局を示す構成図である。 第 1 0図はこの発明の実施の形態 3による移動局を示す構成図である 第 1 1図は移動速度毎の B L E R / S I R特性を示すグラフ図である 第 1 2図は S I Rテーブルを示す説明図である。  FIG. 9 is a configuration diagram showing a base station according to Embodiment 3 of the present invention. FIG. 10 is a block diagram showing a mobile station according to Embodiment 3 of the present invention. FIG. 11 is a graph showing BLER / SIR characteristics for each moving speed. FIG. 12 is an explanation showing an SIR table. FIG.
第 1 3図は測定値受信部の内部構成を示す構成図である。  FIG. 13 is a configuration diagram showing the internal configuration of the measurement value receiving unit.
第 1 4図は H S D P Aにおける主なチャネルを示す説明図である。 第 1 5図はマルチコ一ド数毎の B L E R / S I R特性を示すグラフ図 である。 発明を実施するための最良の形態  FIG. 14 is an explanatory diagram showing main channels in HSDPA. FIG. 15 is a graph showing BLER / SIR characteristics for each number of multicodes. BEST MODE FOR CARRYING OUT THE INVENTION
以下、 この発明をより詳細に説明するために、 この発明を実施するた めの最良の形態について、 添付の図面に従って説明する。  Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.
実施の形態 1 . Embodiment 1
第 1図はこの発明の実施の形態 1による基地局を示す構成図であり、 図において、 1はトランスポートプロックに分割された送信情報を入力 すると、 そのトランスポートブロックに対して誤り訂正を行うとともに 、 そのトランスポートプロックの符号化率を変更する可変レート符号化 部、 2は可変レート符号化部 1により符号化された トランスポートプロ ヅクに対してイン夕一リーブ処理を実施するイン夕一リーバ、 3はイ ン ターリーバ 2の出力データであるビッ トデータをシンボルデ一夕に変換 する可変変調部であり、 可変変調部 3は H S D P A送信電力制御部 5が 指示する変調符号化方式 （MC S : Mo d u l a t i o n and C o d i n g S c h eme) にしたがってビヅ トデータをシンボルデ一 夕に変換する。 FIG. 1 is a configuration diagram showing a base station according to Embodiment 1 of the present invention, In the figure, 1 is a variable rate coding unit for inputting transmission information divided into a transport block, performing error correction on the transport block, and changing the coding rate of the transport block, and 2 An interleaver that performs interleave processing on the transport park encoded by the variable-rate encoder 1, and 3 converts bit data that is output data of the interleaver 2 into symbol data. The variable modulator 3 converts bit data into symbol data in accordance with a modulation and coding scheme (MCS) specified by the HSDPA transmission power controller 5. .
4は可変変調部 3から出力されたシンボルデータを拡散変調する拡散 変調部、 5は移動局から通信路の品質測定値を受信すると、 その品質測 定値に応じて変調符号化方式 MC Sを選択し、 その品質測定値と当該変 調符号化方式 M C Sにおける必要最小限の品質値との差分値を計算し、 その差分値に基づいて拡散変調部 4から出力される拡散変調信号の送信 電力を制御する H S D P A送信電力制御部、 6は H S D P A送信電力制 御部 5から出力される拡散変調信号を無線周波数変換してアンテナに出 力する RF部である。  4 is a spread modulator that spreads and modulates the symbol data output from the variable modulator 3; 5 receives a measured channel quality value from the mobile station and selects the modulation coding scheme MCS according to the quality measured value. Then, a difference value between the measured quality value and the minimum necessary quality value in the modulation coding scheme MCS is calculated, and based on the difference value, the transmission power of the spread modulation signal output from the spread modulator 4 is calculated. An HSDPA transmission power control unit 6 to be controlled is an RF unit that converts a spread modulation signal output from the HSDPA transmission power control unit 5 into a radio frequency and outputs the converted signal to an antenna.
1 1は移動局から通信路の品質測定値として S I R値 （ 3 GP Pの専 門用語としては I 0 r / I o c値と呼ばれる） を受信する測定値受信 部 （受信手段） である。 ただし、 この実施の形態 1では、 移動局から S I R値を受信するものについて説明するが、 これに限るものではなく、 例えば、 C / I値や S N R値を受信するようにしてもよい。  Reference numeral 11 denotes a measurement value reception unit (reception means) that receives an SIR value (referred to as I0r / Ioc value in 3GPP terminology) as a communication channel quality measurement value from the mobile station. However, in the first embodiment, the case where the SIR value is received from the mobile station will be described. However, the present invention is not limited to this. For example, a C / I value or an SNR value may be received.
1 2は選択可能な変調符号化方式 M C Sが複数存在する場合、 各変調 符号化方式 MC Sの所要 S I R値を計算する所要 S I R値計算部、 1 3 は測定値受信部 1 1により受信された S I IU直と所要 S I R値計算部 1 JP02/03462 1 2 is a required SIR value calculator for calculating a required SIR value of each modulation and coding scheme MCS when there are a plurality of selectable modulation and coding schemes MCS, 13 is received by the measurement value receiving section 11 SI IU direct and required SIR value calculator 1 JP02 / 03462
7  7
2によ り計算された各変調符号化方式 M C Sの所要 S I R値とを参照し て、 最適な変調符号化方式 M C Sを選択する M C S決定部、 14は MC S決定部 1 3により選択された変調符号化方式 M C Sを受けると、 全て の移動局のパケッ ト通信要求と基地局のリソース状況を勘案して、 変調 符号化方式 MC Sを最終決定する AM C Sスケジューラである。 なお、 所要 S I R値計算部 1 2， M C S決定部 1 3及び AMC Sスケジューラ 1 4から方式選択手段が構成されている。 The MCS determining unit that selects the optimal modulation and coding system MCS by referring to the required SIR value of each modulation and coding system MCS calculated by 2 and 14 is the modulation selected by the MCS determining unit 13 An AMCS scheduler that, upon receiving the coding scheme MCS, finally determines the modulation coding scheme MCS in consideration of the packet communication requests of all mobile stations and the resource status of the base station. The required SIR value calculation unit 12, the MCS determination unit 13 and the AMCS scheduler 14 constitute a method selection unit.
1 5は AMC Sスケジューラ 1 4によ り最終決定された変調符号化方 式 MC Sにおける必要最小限の品質値 S I Rm i nを推測し、 測定値受信 部 1 1によ り受信された S I I 値と必要最小限の品質値 S I Rm i nとの 差分値 （以下、 S I Rオフセッ ト という） を計算する S I Rオフセッ ト 計算部、 1 6は S I Rオフセッ ト計算部 1 5によ り計算された S I Rォ フセッ トから送信電力オフセッ トを計算して、 デフオル 卜の固定送信鼋 力から送信電力オフセッ トを減算し、 その減算結果を拡散変調信号の送 信電力とする送信電力制御部である。 なお、 S I Rオフセッ ト計算部 1 5及び送信電力制御部 1 6から電力制御手段が構成されている。 15 estimates the minimum required quality value SIR min in the modulation and coding scheme MCS finally determined by the AMC scheduler 14 and compares the SIR value received by the measurement value reception unit 11 with the SII value. Minimum required quality value SIR offset calculator that calculates the difference from SIR min (hereinafter referred to as SIR offset), and 16 is the SIR offset calculated by SIR offset calculator 15 The transmission power control unit calculates the transmission power offset, subtracts the transmission power offset from the default fixed transmission output, and uses the result of the subtraction as the transmission power of the spread modulation signal. It should be noted that the SIR offset calculation section 15 and the transmission power control section 16 constitute a power control means.
第 2図はこの発明の実施の形態 1による移動局を示す構成図であり、 図において、 2 1は下りシグナリ ングに含まれるコ一 ド番号と符号番号 で拡散変調信号を逆拡散する逆拡散部、 2 2は予め受信した変調符号化 方式で、 逆拡散部 2 1から出力されるシンボルデ一夕をビッ トデ一夕に 変換する復調部、 23は復調部 2 2から出力されるビッ トデ一夕に対し てディ ン夕一リーブ処理を実施するディ ン夕ーリーバ、 24はディ ン夕 —リーバ 2 3から出力される ビヅ トデータである ト ラ ンスポー トプロ ヅ クを復号化する可変レ一ト復号部である。  FIG. 2 is a configuration diagram showing a mobile station according to Embodiment 1 of the present invention. In the figure, reference numeral 21 denotes a despreading device for despreading a spread modulation signal with a code number and a code number included in downlink signaling. , A demodulation unit 22 for converting the symbol data output from the despreading unit 21 into a bit data, and 23 a bit data output from the demodulation unit 22. A din evening reaver that performs a din evening reeve process for the evening, and a variable rate 24 that decodes a transport protocol that is bit data output from the din evening 23 It is a decoding unit.
2 5は共通パイロッ トチャネル C P I C Hを受信する C P I C H受信 部、 2 6は C P I C H受信部 2 5により受信された共通パイロッ トチヤ ネル C P I CHと自己宛の個別データチャネル電力配分及び拡散率の情 報を参照して自己宛のチャネルの S I R値を計算する S I R値測定部、 27は S I R値測定部 2 6により計算された S I R値を基地局に送信す るフ ィードバック送信部である。 25 is a CPICH receiving unit that receives the common pilot channel CPICH, 26 is a common pilot channel received by the CPICH receiving unit 25 SIR value measurement unit that calculates the SIR value of the channel destined for itself by referring to the information on the CPI CH and the dedicated data channel power allocation and spreading factor addressed to itself.27 is the SIR calculated by the SIR value measurement unit 26. This is a feedback transmission unit that transmits the value to the base station.
第 3図は基地局における送信電力制御を示すフローチヤ一トであり、 第 4図は移動局における品質測定処理を示すフローチャートである。 次に動作について説明する。  FIG. 3 is a flowchart showing transmission power control in the base station, and FIG. 4 is a flowchart showing quality measurement processing in the mobile station. Next, the operation will be described.
H S D PAにおいては、 通信路の通信状況が変化しても、 所定の通信 品質 （例えば、 ブロックエラ一レ一 ト B L ER、 フ レームエラ一レー ト FER) を満足するために、 複数の変調符号化方式 MC Sを用意してい る。 各変調符号化方式 M C Sは相互に異なる S I R値を要求する。  In HSD PA, even if the communication conditions on the communication channel change, multiple modulation and coding methods are used to satisfy the predetermined communication quality (for example, block error rate BLER, frame error rate FER). Method MCS is available. Each modulation and coding scheme MCS requires a different SIR value.
一般的に変調指数と符号化レートの高い変調符号化方式 M C Sは伝送 速度が高いが、 より高い S I R値を要求する。  In general, the modulation and coding scheme MCS with a high modulation index and coding rate has a high transmission rate, but requires a higher SIR value.
第 5図は各変調符号化方式 M C Sにおける B L E RZS I R特性を示 すグラフ図であり、 図において、 B L E R t hは所定の通信品質を示す ブロックエラーレートの閾値であり、 A〜； Fは閾値 B L E Rt hを満足 させる変調符号化方式 MC S ( 1 ) 〜 （ 6 ) の所要 S I R値である。 最初に、 基地局の動作を具体的に説明する。 FIG. 5 is a graph showing BLE RZS IR characteristics in each modulation and coding scheme MCS. In the figure, BLER th is a threshold of a block error rate indicating a predetermined communication quality, and A to F are thresholds of BLER. This is the required SIR value of the modulation coding scheme MCS (1) to (6) that satisfies th . First, the operation of the base station will be specifically described.
可変レート符号化部 1は、 トランスポートプロックに分割された送信 情報を入力すると、 そのトランスポートブロックに対して誤り訂正を行 うとともに、 そのトランスポートブロックの符号化率を変更する。 なお 、 トランスポートプロックの符号化率は、 AMC Sスケジューラ 1 4か ら与えられる。  When the transmission information divided into the transport blocks is input, the variable rate coding unit 1 performs error correction on the transport block and changes the coding rate of the transport block. The coding rate of the transport block is given from the AMS scheduler 14.
イン夕一リーバ 2は、 可変レート符号化部 1から符号化された トラン スボートプロックを受けると、 その トランスポートブロックに対してィ ン夕ー リ—プ処理を実施する。 イ ン夕一リーブ処理はチャネル毎に実施されるが、 イ ン夕一リ一ブ処 理は、 例えば、 行 X列構成のメモリが存在する場合、 そのメモリに対す るデータの書込処理を列方向に実施する一方、 データの読込処理を行方 向に実施するものである。 イ ン夕一リーブ処理を実施することによ り、 移動体通信特有の ドップラーに起因するレベル低下の長時間継続を緩和 することができる。 Upon receiving the encoded transport block from the variable rate encoding unit 1, the in-band reaver 2 performs the in-loop processing on the transport block. The in-night and leave processing is performed for each channel, but the in-and-out leave processing is performed, for example, when there is a memory having a row and an X-column configuration, data write processing to the memory is performed. While reading is performed in the column direction, data reading processing is performed in the row direction. By performing the overnight reeve processing, it is possible to mitigate the long-term continuation of the level decrease caused by Doppler peculiar to mobile communication.
可変変調部 3は、 イ ン夕一リーバ 2がィ ン夕ーリーブ処理を実施する と、 イ ンターリーバ 2の出力データであるビヅ トデ一夕をシンボルデ一 夕に変換する。 即ち、 可変変調部 3は、 A M C Sスケジューラ 1 4が指 示する変調符号化方式 M C Sにしたがってビッ トデータをシンボルデ一 夕に変換する。 変調符号化方式 M C Sに定義されている変調方式として は、 例えば、 Q P S K， 1 6 Q A M , 6 4 Q A Mなどがある。  When the interleaver 2 performs the interleave process, the variable modulator 3 converts the bit data that is the output data of the interleaver 2 into the symbol data. That is, the variable modulator 3 converts the bit data into symbol data according to the modulation and coding scheme MCS indicated by the AMS scheduler 14. Examples of the modulation scheme defined in the modulation and coding scheme MCS include QPSK, 16QAM, and 64QAM.
拡散変調部 4は、 可変変調部 3からシンボルデ一夕を受けると、 A M C Sスケジューラ 1 4から与えられるチヤネライゼーション符号番号 · 符号数で、 そのシンボルデ一夕を拡散変調する。 例えば、 符号数が 5の 場合、 5つのチヤネライゼ一ション符号を用いてシンボルデ一夕の拡散 変調が行われる。  Upon receiving the symbol data from the variable modulator 3, the spreading modulator 4 spread-modulates the symbol data with the channelization code number and the number of codes given from the AMS scheduler 14. For example, if the number of codes is 5, spread modulation of symbol data is performed using five channelization codes.
H S D P A送信電力制御部 5は、 最大伝送速度の低下を招く ことなく 、 送信電力の小電力化を図るため、 拡散変調部 4から拡散変調信号を受 けると、 その拡散変調信号の送信電力を適宜制御する。  When the HSDPA transmission power control unit 5 receives a spread modulation signal from the spread modulation unit 4 in order to reduce the transmission power without reducing the maximum transmission rate, the HSDPA transmission power control unit 5 appropriately adjusts the transmission power of the spread modulation signal. Control.
即ち、 H S D P A送信電力制御部 5の測定値受信部 1 1は、 移動局が 通信路の品質測定値として S I R値を送信すると、 その S I R値を受信 する （ステップ S T 1 ) 。 移動局における S I R値の測定処理は後述す る o  That is, when the mobile station transmits the SIR value as the communication channel quality measurement value, the measurement value reception unit 11 of the HSDPA transmission power control unit 5 receives the SIR value (step ST1). The process of measuring the SIR value at the mobile station will be described later.
一方、 所要 S I I 直計算部 1 2は、 第 5図に示すように、 選択可能な 変調符号化方式 M C Sが 6つ存在する場合、 予め、 変調符号化方式 M C S ( 1 ) 〜 （ 6 ) の所要 S I R値を計算する。 第 7図は所要 S I R値計 算部 1 2の計算結果である所要 S I R値を格納する S I Rテーブルを示 す説明図である。 On the other hand, as shown in FIG. 5, when there are six selectable modulation and coding schemes MCS, the required SII direct calculation section 12 Calculate the required SIR values of S (1) to (6). FIG. 7 is an explanatory diagram showing an SIR table for storing a required SIR value, which is a calculation result of the required SIR value calculation unit 12.
測定値受信部 1 1が移動局から S I R値を受信すると、 MC S決定部 1 3は、 第 7図の S I Rテーブルを参照して、 所要の S I R値を満足で きる変調符号化方式の中から S I R値が最大のものを選択する （ステツ プ S T 2 ) 。 一般的に M C Sレベルは情報レートの昇順で並べられる。 M C Sレベルが高いほど情報レートも高くなり、 所要の S I R値も高く なる。  When the measured value receiving section 11 receives the SIR value from the mobile station, the MCS determining section 13 refers to the SIR table in FIG. 7 and selects one of the modulation and coding schemes that can satisfy the required SIR value. The one with the largest SIR value is selected (step ST2). Generally, the MCS levels are arranged in ascending order of information rate. The higher the MCS level, the higher the information rate and the higher the required SIR value.
例えば、 測定値受信部 1 1によ り受信された S I R値が D < S I R値 < Eの関係を満足する場合、 変調符号化方式 M C S ( 1 ) , ( 2 ) , ( 3 ) ， ( 4 ) の中で、 品質値が情報レートが最高である変調符号化方式 M C S ( 4 ) を選択する。  For example, if the SIR value received by the measurement value receiving unit 11 satisfies the relationship of D <SIR value <E, the modulation and coding scheme MCS (1), (2), (3), (4) Among them, the modulation coding method MCS (4) having the highest quality value and the highest information rate is selected.
AM C Sスケジューラ 1 4は、 M C S決定部 1 3により選択された変 調符号化方式 M C Sを受けると、 全ての移動局のパケッ ト通信要求と基 地局のリソース状況を勘案して変調符号化方式 M C Sを最終決定する。  Upon receiving the modulation and coding scheme MCS selected by the MCS deciding unit 13, the AMCS scheduler 14 takes into account the packet communication requests of all mobile stations and the resource status of the base station, and modulates the coding scheme. Finalize MCS.
そして、 AM C Sスケジューラ 1 4は、 その変調符号化方式 M C Sに 定義されている符号化率を可変レート符号化部 1に出力し、 変調方式を 可変変調部 3に出力し、 チヤネライゼ一シヨン符号番号 · 符号数を拡散 変調部 4に出力する。  Then, the AMCS scheduler 14 outputs the coding rate defined in the modulation coding scheme MCS to the variable rate coding section 1, outputs the modulation scheme to the variable modulation section 3, and sets the channelization code number. · Output the number of codes to spreading modulator 4.
S I Rオフセッ ト計算部 1 5は、 AM C Sスケジューラ 1 4が変調符 号化方式 M C Sを最終決定すると、 その変調符号化方式 M C Sにおける 必要最小限の品質値 S I Rm i nを推測する （第 6図を参照） 。 例えば、 変調符号化方式 M C Sの所要 S ェ R値に所定の係数を乗算することによ り必要最小限の品質値 S I Rm i nを計算する。 When the AMCS scheduler 14 finally determines the modulation and coding scheme MCS, the SIR offset calculator 15 estimates the minimum required quality value SIR min in the modulation and coding scheme MCS (see FIG. 6). ). For example, the minimum required quality value SIR min is calculated by multiplying the required S value of the modulation and coding scheme MCS by a predetermined coefficient.
そして、 測定値受信部 1 1により受信された S I R値と必要最小限の 品質値 S I Rm i nとの差分値を S I Rオフセッ トとして計算する （ステ ヅ プ S T 3 ) 。 ただし、 下記に示すように、 所定の S I Rマージンを考 慮して S I Rオフセヅ トを計算してもよい。 Then, the SIR value received by the measurement value The difference from the quality value SIR min is calculated as an SIR offset (step ST3). However, as shown below, the SIR offset may be calculated in consideration of a predetermined SIR margin.
S I Rオフセ ヅ h = S I R値一 S I Rm i n- S I Rマ一ジン 送信電力制御部 1 6は、 S I Rオフセ ヅ ト計算部 1 5が S I Rオフセ ッ トを計算すると、 一般的に、 S I R値が送信電力に比例するので、 例 えば、 下記に示すように、 S I Rオフセッ トから送信電力オフセッ トを 計算する （ステップ S T 4 ) 。 SIR offset ヅ h = SIR value-SIR min -SIR margin The transmission power controller 16 calculates the SIR offset by the SIR offset calculator 15. Since it is proportional, for example, as shown below, the transmission power offset is calculated from the SIR offset (step ST4).
送信電力オフセ ッ ト = S I Rオフセ ヅ ト  Transmit power offset = SIR offset
そして、 デフオルトの固定送信電力から送信電力オフセッ トを減算し 、 その減算結果を摅散変調信号の送信電力に決定する （ステップ S T 5 Then, the transmission power offset is subtracted from the default fixed transmission power, and the subtraction result is determined as the transmission power of the spread modulation signal (step ST5).
) o ) o
送信電力 =デフオル トの固定送信電力—送信電力オフセ ヅ ト なお、 第 8図は 1ビッ ト当りのデフオル卜の固定送信電力と送信電力 オフセ ッ トの関係を示す概念図である。 '  Transmission power = Default fixed transmission power−Transmission power offset FIG. 8 is a conceptual diagram showing the relationship between default fixed transmission power and transmission power offset per bit. '
R F部 6は、 上記のようにして、 H S D P A送信電力制御部 5が拡散 変調信号の送信電力を制御すると、 その拡散変調信号を無線周波数変換 してアンテナに出力することにより、 その拡散変調信号を移動局に送信 する。  When the HSDPA transmission power control section 5 controls the transmission power of the spread modulation signal as described above, the RF section 6 converts the spread modulation signal to a radio frequency and outputs it to the antenna, thereby converting the spread modulation signal. Send to mobile station.
次に、 移動局の動作を具体的に説明する。  Next, the operation of the mobile station will be specifically described.
移動局のアンテナが基地局から送信された拡散変調信号を受信すると 、 その拡散変調信号は無線周波数変換が実施された後、 逆拡散部 2 1に 与えられる。  When the mobile station antenna receives the spread modulation signal transmitted from the base station, the spread modulation signal is applied to despreading section 21 after radio frequency conversion is performed.
逆拡散部 2 1は、 下りシグナリングに含まれるコ一ド番号と符号番号 で拡散変調信号を逆拡散し、 シンボルデ一夕を出力する。  The despreading unit 21 despreads the spread modulation signal with the code number and the code number included in the downlink signaling, and outputs a symbol data.
復調部 2 2は、 逆拡散部 2 1からシンボルデ一夕を受けると、 予め受 信した変調符号化方式 MC Sで、 そのシンボルデ一夕をビッ トデータに 変換する。 Upon receiving the symbol data from the despreading unit 21, the demodulation unit 22 receives it in advance. The received modulation and coding scheme MCS converts the symbol data into bit data.
ディ ン夕一リーバ 2 3は、 復調部 2 2から ビッ トデータを受けると、 そのビヅ トデ一夕に対してディ ンターリープ処理を実施する。 ディ ン夕 —リーバ 2 3のディン夕一リ一ブ処理は、 イ ンターリーノ' 2のイ ン夕一 リーブ処理と逆の処理である。  Upon receiving the bit data from the demodulation unit 22, the deinterleaver 23 performs an interleave process on the bit data. Din Yu — The Din Yi Reeve processing of Lever 23 is the reverse processing of the InterLino's 2 In Yi Reeve processing.
可変レー ト復号部 24は、 ディ ン夕一リーバ 2 3からビッ トデータで ある トランスポートブロックを受けると、 その トランスポートブロック を復号化する。  Upon receiving the transport block, which is bit data, from the digital receiver 23, the variable rate decoding unit 24 decodes the transport block.
一方、 CP I CH受信部 2 5は、 共通パイ ロッ トチャネル CP I CH を受信する （ステップ S T 1 1 ) 。  On the other hand, the CP I CH receiving section 25 receives the common pilot channel CP I CH (step ST 11).
S I R値測定部 2 6は、 C P I C H受信部 2 5が共通パイロッ トチヤ ネル C P I C Hを受信すると、 その共通パイ ロッ トチャネル CP I C H と自己宛の個別データチャネル電力'配分及び拡散率の倩報を参照して自 己宛のチャネルの S I R値を計算する （ステヅプ S T 1 2 ) o  When the CPICH receiving unit 25 receives the common pilot channel CPICH, the SIR value measuring unit 26 refers to the common pilot channel CP ICH and the dedicated data of the individual data channel power allocation and spreading factor addressed to itself. To calculate the SIR value of the channel addressed to itself (step ST12) o
フィ一 ドバック送信部 2 7は、 S I R値測定部 2 6が S I R値を計算 すると、 その S I R値を基地局に送信する （ステップ S T 1 3) 。  When the SIR value measurement unit 26 calculates the SIR value, the feedback transmission unit 27 transmits the SIR value to the base station (step ST13).
以上で明らかなように、 この実施の形態 1によれば、 H SD PA送信 電力制御部 5が S I R値を受信すると、 その S I R値に応じて変調符号 化方式 MC Sを選択し、 その S I R値と当該変調符号化方式 M C Sにお ける必要最小限の品質値 S I Rm i nとの差分値である S I Rオフセッ ト を計算し、 その S I Rオフセッ トに基づいて拡散変調部 4から出力され る拡散変調信号の送信電力を制御するように構成したので、 最大伝送速 度の低下を招く ことなく、 送信電力の小電力化を図ることができる効果 を奏する。 実施の形態 2 . As is clear from the above, according to the first embodiment, when the HSDPA transmission power control unit 5 receives the SIR value, it selects the modulation and coding scheme MCS according to the SIR value, and selects the SIR value. SIR offset, which is the difference value between the required minimum quality value SIR min and the modulation and coding scheme MCS, is calculated, and based on the SIR offset, the spread modulation signal output from the spread modulator 4 is calculated. Since the transmission power is controlled, the transmission power can be reduced without lowering the maximum transmission speed. Embodiment 2
上記実施の形態 1では、 移動局が S I R値を計算して基地局に送信す るものについて示したが、 移動局が第 7図に示すような S I Rテーブル を保持することにより、 M C S決定部 1 3 と同様にして変調符号化方式 M C Sを選択し、 その変調符号化方式 M C Sの選択情報を基地局に送信 するようにしてもよい。  In the first embodiment, the case where the mobile station calculates the SIR value and transmits it to the base station has been described. However, the mobile station holds the SIR table as shown in FIG. In the same manner as in 3, the modulation and coding scheme MCS may be selected, and the selection information of the modulation and coding scheme MCS may be transmitted to the base station.
この場合、 基地局の測定値受信部 1 1が、 移動局から S I R値の代わ りに、 変調符号化方式 M C Sの選択情報を受信するので、 M C S決定部 1 3が、 その選択情報が示す変調符号化方式を選択するようにする。 こ れにより、 基地局の処理負担を軽減することができる効果を奏する。 また、 移動局が基地局の S I Rオフセッ 卜計算部 1 5 と同様にして S I Rオフセヅ トを計算し、 その S I Rオフセヅ トを基地局に送信するよ うにしてもよい。  In this case, the measured value receiving section 11 of the base station receives the selection information of the modulation and coding scheme MCS instead of the SIR value from the mobile station. Select an encoding method. This has the effect of reducing the processing load on the base station. Further, the mobile station may calculate the SIR offset in the same manner as the SIR offset calculation unit 15 of the base station, and transmit the SIR offset to the base station.
この場合、 基地局の測定値受信部 1 1が S I Rオフセッ トを受信し、 その S I Rオフセヅ トを送信電力制御部 1 6に出力する。 これにより、 基地局の S I Rオフセッ ト計算部 1 5を省略することができる効果を奏 する。 実施の形態 3 .  In this case, measured value receiving section 11 of the base station receives the SIR offset and outputs the SIR offset to transmission power control section 16. This has an effect that the SIR offset calculator 15 of the base station can be omitted. Embodiment 3.
第 9図はこの発明の実施の形態 3による基地局を示す構成図であり、 図において、 第 1図と同一符号は同一または相当部分を示すので説明を 省略する。  FIG. 9 is a block diagram showing a base station according to Embodiment 3 of the present invention. In the figure, the same reference numerals as in FIG. 1 denote the same or corresponding parts, and a description thereof will be omitted.
3 1は移動局から S I R値を受信するとともに、 移動局の移動速度又 はドップラー周波数を受信する測定値受信部 （受信手段） 、 3 2は選択 可能な変調符号化方式 M C Sが複数存在する場合、 移動局の移動速度や ドッブラー周波数を考慮して、 各変調符号化方式 M C Sの所要 S I R値 を計算する所要 S I R値計算部、 3 3は測定値受信部 3 1により受信さ れた S I R値及び移動速度又はドッブラ一周波数と、 所要 S I R値計算 部 3 2により計算された各変調符号化方式 M C Sの所要 S I R値とを参 照して、 最適な変調符号化方式 M C Sを選択する M C S決定部である。 なお、 所要 S I R値計算部 3 2及び M C S決定部 3 3は方式選択手段を 構成している。 3 1 is a measurement value receiving unit (reception means) that receives the SIR value from the mobile station and also receives the moving speed or Doppler frequency of the mobile station. 3 2 is when there are multiple selectable modulation and coding schemes MCS. , The required SIR value of each modulation and coding scheme The required SIR value calculation unit that calculates the SIR value and the moving speed or the Doppler frequency received by the measurement value reception unit 31 and each modulation and coding scheme calculated by the required SIR value calculation unit 32 An MCS determination unit that selects the optimal modulation and coding scheme MCS by referring to the required SIR value of the MCS. The required SIR value calculation unit 32 and the MCS determination unit 33 constitute a method selection means.
3 4は A M C Sスケジューラ 1 4により最終決定された変調符号化方 式 M C Sにおける必要最小限の品質値 S I R m i nを推測し、 測定値受信 部 3 1により受信された S I R値と必要最小限の品質値 S I R m i nとの 差分値である S I Rオフセッ トを計算する S I Rオフセッ ト計算部 （電 力制御手段） である。 3 4 is the modulation and coding method finally determined by the AMCS scheduler 14 The minimum required quality value SIR min in the MCS is estimated, and the SIR value received by the measurement value receiving unit 3 1 and the minimum required quality value This is the SIR offset calculator (power control means) that calculates the SIR offset, which is the difference value from SIR min .
第 1 0図はこの発明の実施の形態 3による移動局を示す構成図であり 、 図において、 第 2図と同一符号は同一または相当部分を示すので説明 を省略する。  FIG. 10 is a block diagram showing a mobile station according to Embodiment 3 of the present invention. In the figure, the same reference numerals as in FIG. 2 denote the same or corresponding parts, and a description thereof will be omitted.
4 1は移動局の移動速度又はドッブラ一周波数を測定する移動測定部 、 4 2は S I R値測定部 2 6により計算された S I R値と移動測定部 4 1により測定された移動速度又はドッブラ一周波数を基地局に送信する フィードバック送信部である。  4 1 is a mobile measuring unit for measuring the moving speed or Doppler frequency of the mobile station, 4 2 is the SIR value calculated by the SIR value measuring unit 26 and the moving speed or Doppler frequency measured by the mobile measuring unit 41 Is transmitted to the base station.
次に動作について説明する。  Next, the operation will be described.
上記実施の形態 1， 2では、 移動局の移動速度やドップラー周波数の 変化を考慮せずに、 変調符号化方式 M C Sを選択するものについて、 移 動局の移動測定部 4 1が移動局の移動速度又はドッブラー周波数を測定 し、 移動局のフィードバック送信部 4 2が S I R値測定部 2 6により計 算された S I R値と移動測定部 4 1により測定された移動速度又はドツ ブラ一周波数を基地局に送信する場合、 基地局が移動局の移動速度又は ドッブラー周波数を考慮して変調符号化方式を選択するようにしてもよ い o In Embodiments 1 and 2 described above, the mobile station mobile measurement unit 41 selects the modulation and coding scheme MCS without considering changes in the mobile station's mobile speed and Doppler frequency. Measures the speed or Doppler frequency, and the feedback transmitter 42 of the mobile station compares the SIR value calculated by the SIR value measuring section 26 with the moving speed or Doppler frequency measured by the mobile measuring section 41 to the base station. , The base station may select the modulation and coding scheme in consideration of the moving speed of the mobile station or the Doppler frequency. O
即ち、 基地局の所要 S I R値計算部 3 2は、 移動局の移動速度やドッ ブラ一周波数が異なると、 変調符号化方式 M C Sにおける B L E R/ S I R特性が変化するので （第 1 1図を参照） 、 第 1 2図に示すように、 選択可能な変調符号化方式 M C Sが 6つ存在する場合、 予め、 移動局の 移動速度 （または ドップラー周波数） 毎に、 変調符号化方式 MC S ( 1 ) 〜 （ 6 ) の所要 S I R値を計算する。 第 1 2図は所要 S I R値計算部 3 2の計算結果である所要 S I R値を格納する S I Rテーブルを示す説 明図である。  In other words, the required SIR value calculation unit 32 of the base station changes the BLER / SIR characteristic in the modulation and coding scheme MCS when the moving speed of the mobile station and the frequency of the docker are different (see FIG. 11). As shown in Fig. 12 and Fig. 12, when there are six selectable modulation and coding schemes MCS, the modulation and coding schemes MCS (1) to Calculate the required SIR value of (6). FIG. 12 is an explanatory diagram showing an SIR table for storing a required SIR value calculated by the required SIR value calculation unit 32.
M C S決定部 3 3は、 測定値受信部 1 1が移動局から S I IU直と移動 速度又は ドヅブラ一周波数を受信すると、 第 1 2図の S I Rテーブルを 参照して、 その S I R値を満足する変調符号化方式 M C Sを少なく とも 1以上検索し、 その中から品質値が最高である変調符号化方式 MC Sを 選択する。  When the measurement value receiving unit 11 receives the SI IU directly from the mobile station and the moving speed or the Doppler frequency, the MCS determination unit 33 refers to the SIR table in Fig. 12 and modulates the signal to satisfy the SIR value. Search for at least one coding method MCS, and select the modulation coding method MCS with the highest quality value from among them.
例えば、 測定値受信部 1 1によ り受信された移動速度が 1 0 kmであ り、 測定値受信部 1 1によ り受信された S I R値が D 2 < S I R値 < E 2の関係を満足する場合、 変調符号化方式 MC S ( 1 ) ， ( 2 ) , ( 3 ) , (4) の中で、 品質値が最高である変調符号化方式 M C S (4) を 選択する。  For example, if the moving speed received by the measurement value reception unit 11 is 10 km and the SIR value received by the measurement value reception unit 11 is D2 <SIR value <E2. If satisfied, the modulation coding method MCS (4) having the highest quality value is selected from the modulation coding methods MCS (1), (2), (3), and (4).
S I Rオフセヅ ト計算部 34は、 AMC Sスケジューラ 1 4が変調符 号化方式 M C Sを最終決定すると、 その変調符号化方式 M C Sにおける 必要最小限の品質値 S I Rm i nを推測する。 When the AMCS scheduler 14 finally determines the modulation and coding scheme MCS, the SIR offset calculator 34 estimates the minimum necessary quality value SIR min in the modulation and coding scheme MCS.
例えば、 測定値受信部 1 1により受信された移動速度が 1 0 kmであ り、 AMC Sスケジューラ 1 4が変調符号化方式 M C S ( 4 ) を最終決 定すると、 変調符号化方式 M C S ( 4 ) の所要 S I R値である D 2に所 定の係数を乗算することによ り必要最小限の品質値 S I Rm i nを計算す る o For example, when the moving speed received by the measurement value receiving unit 11 is 10 km, and the AMS scheduler 14 finally determines the modulation and coding scheme MCS (4), the modulation and coding scheme MCS (4) The required minimum quality value SIR min is calculated by multiplying the required SIR value of D2 by a predetermined coefficient. O
そして、 測定値受信部 3 1によ り受信された S I R値と必要最小限の 品質値 S I Rm i nとの差分値を S I Rオフセッ ト として計算する。 Then, a difference value between the SIR value received by the measurement value receiving unit 31 and the required minimum quality value SIR min is calculated as an SIR offset.
その他は、 上記実施の形態 1と同様であるため説明を省略する。  Other configurations are the same as those in the first embodiment, and a description thereof will not be repeated.
以上で明らかなように、 この実施の形態 3によれば、 移動局から移動 速度又は ドッブラー周波数の測定値を受信すると、 その測定値を考慮し て変調符号化方式 MC Sを選択するように構成したので、 移動局が移動 中であっても適正な変調符号化方式 M C Sを選択して送信電力制御を実 施することができるようになり、 その結果、 通信容量を増加することが できる効果を奏する。 実施の形態 4.  As is clear from the above, according to the third embodiment, when a measured value of the moving speed or the Doppler frequency is received from the mobile station, the modulation and coding scheme MCS is selected in consideration of the measured value. Therefore, even when the mobile station is moving, it is possible to select an appropriate modulation and coding scheme MCS and perform transmission power control, and as a result, it is possible to increase the communication capacity. Play. Embodiment 4.
上記実施の形態 3で説明したように、 移動局の移動速度や ドップラー 周波数が異なると、 変調符号化方式 M C Sにおける B L ERZS I R特 性が変化するので、 M C S決定部 3 3が S I R値に基づいて変調符号化 方式 M C Sを適切に選択するには、 移動速度又は ドッブラー周波数別の S I Rテーブルを用意する必要がある。  As described in the third embodiment, if the moving speed or the Doppler frequency of the mobile station is different, the BL ERZS IR characteristic in the modulation and coding scheme MCS changes, so that the MCS determination unit 33 based on the SIR value In order to properly select the modulation and coding scheme MCS, it is necessary to prepare SIR tables for each moving speed or Doppler frequency.
一方、 基地局が通信路の品質測定値として S I R値ではなく、 ビッ ト エラ一レート B L E Rを受信した場合でも、 例えば、 S I Rテーブルに 相当する B L E Rテーブルを用意すれば、 ビッ トエラーレート B L E R から変調符号化方式 M C Sを選択することができる。  On the other hand, even if the base station receives a bit error rate BLER instead of an SIR value as a communication channel quality measurement value, for example, if a BLER table equivalent to the SIR table is prepared, modulation from the bit error rate BLER will be performed. Coding method MCS can be selected.
ビヅ トエラ一レート B L ERは、 移動局の移動速度や F a d i n g環 境要素が考慮済みであるため、 移動速度別の B L E Rテーブルを用意す る必要がないメ リ ッ トがある。  The bit error rate BLER has an advantage that it is not necessary to prepare a BLER table for each moving speed because the moving speed of the mobile station and the Fading environment element have been considered.
しかし、 基地局における初期送信時又は不連続送信時には、 ビッ トェ ラーレート B L ERに基づいて変調符号化方式 M C Sを選択することが できないデメ リ ッ トがある。 However, at the time of initial transmission or discontinuous transmission at the base station, the modulation and coding scheme MCS may be selected based on the bit error rate BLER. Some disadvantages cannot be achieved.
そこで、 この実施の形態 4では、 基地局の測定値受信部 1 1が移動局 から S I R値とビッ トエラ一レート B L ERを受信し、 必要に応じて S I R値又はビッ トエラーレート B L E Rを使用して変調符号化方式 M C Sを選択するようにする。  Therefore, in Embodiment 4, the measured value receiving section 11 of the base station receives the SIR value and the bit error rate BLER from the mobile station, and uses the SIR value or the bit error rate BLER as necessary. To select the modulation and coding scheme MCS.
具体的には、 測定値受信部 1 1が第 1 3図に示すような送信状況判断 部 5 1と切替部 5 2を内蔵し、 送信状況判断部 5 1が基地局における送 信状況が初期送信時であるか、 不連続送信時であるか、 連続送信時であ るかを判断する。  Specifically, the measurement value receiving section 11 incorporates a transmission status determination section 51 and a switching section 52 as shown in FIG. 13, and the transmission status determination section 51 initializes the transmission status at the base station. Judge whether it is during transmission, discontinuous transmission, or continuous transmission.
そして、 切替部 5 2は、 送信状況判断部 5 1が初期送信時又は不連続 送信時であると判断すると、 移動局より受信した S I R値を MC S決定 部 1 3等に出力して、 その S I R値に基づく変調符号化方式 M C Sの選 択ゃ、 送信電力の制御を行わせる。  Then, when the transmission status determination unit 51 determines that the transmission is at the time of initial transmission or discontinuous transmission, the switching unit 52 outputs the SIR value received from the mobile station to the MCS determination unit 13 and the like, and the Selects modulation and coding scheme MCS based on SIR value, and controls transmission power.
一方、 送信状況判断部 5 1が連続送信時であると判断すると、 移動局 より受信したビヅ トエラ一レ一ト B L ERを MC S決定部 1 3等に出力 して、 そのビヅ トエラーレー ト B L ERに基づく変調符号化方式 M C S の選択や、 送信電力の制御を行わせる。  On the other hand, if the transmission status determination unit 51 determines that continuous transmission is being performed, the bit error rate BLER received from the mobile station is output to the MCS determination unit 13 and the like, and the bit error rate is output. Selects modulation coding scheme MCS based on BL ER and controls transmission power.
なお、 移動局の S I R測定部 2 6は、 S I R値の測定の他、 ビッ トェ ラ一レ一ト B L E Rの測定を行う。 即ち、 共通パイロヅ トチャネル C P I CH、 付随 H S— S C CHチャネル （MC Sレベルなどの情報を事前 に移動局に知らせるチャネル） 、 または、 自己への H S— D S C Hチヤ ネル （移動局宛の個別パケッ トデ一夕チャネル） のビッ トエラ一レート B L E Rを測定し、 フィードバック送信部 2 7が S I R値とビッ トエラ 一レート B L ERを基地局に送信する。  The SIR measuring section 26 of the mobile station measures the bit rate B BLE in addition to measuring the SIR value. That is, the common pilot channel CPI CH, the associated HS-SC CH channel (a channel for notifying the mobile station of information such as the MCS level in advance), or the HS-DSCH channel to the mobile station itself (individual packet data addressed to the mobile station). The feedback transmitter 27 measures the bit error rate BLER of the overnight channel) and sends the SIR value and bit error rate BLER to the base station.
なお、 第 14図は H S D P Aにおける主なチャネルを示す説明図であ る ο この実施の形態 4によれば、 送信状況が変化しても通信を継続するこ とができる効果を奏する。 実施の形態 5 . FIG. 14 is an explanatory diagram showing main channels in HSDPA. According to the fourth embodiment, there is an effect that communication can be continued even if the transmission status changes. Embodiment 5
上記実施の形態 1〜 4では、 特に言及していないが、 マルチコード数 が異なると、 第 1 5図に示すように、 変調符号化方式 M C Sにおける B L E R / S I R特性が変化する。  In Embodiments 1 to 4, although not particularly mentioned, if the number of multicodes is different, as shown in FIG. 15, the BLER / SIR characteristic in the modulation and coding scheme MCS changes.
即ち、 H D S C Hの電力配分が同じでもマルチコード数が変わると、 変調符号化方式 M C Sにおける B L E R Z S I R特性が変化し、 一般的 には、 マルチコード数が多く となると、 1コード当りの電力が減るため 誤り率特性が劣化する。  In other words, even if the power distribution of HDSCH is the same, if the number of multi-codes changes, the BLERZSIR characteristics in the modulation and coding scheme MCS will change. The rate characteristics deteriorate.
そこで、 この実施の形態 5では、 移動局が S I R値を送信する際、 セ ル内干渉を減少する観点から、 所望のマルチコ一ド数を基地局に送信す る。  Therefore, in the fifth embodiment, when the mobile station transmits the SIR value, a desired number of multi-codes is transmitted to the base station from the viewpoint of reducing intra-cell interference.
基地局は、 測定値受信部 1 1が移動局から S I R値と所望のマルチコ —ド数を受信すると、 M C S決定部 1 3が所望のマルチコ一ド数を考慮 して、 その S I R値から変調符号化方式 M C Sを選択する。 なお、 所要 S I IU直計算部 1 2は事前にマルチコ一ド数別の S I Rテーブルを生成 するようにする。  When the measured value receiving unit 11 receives the SIR value and the desired number of multicodes from the mobile station, the MCS determination unit 13 considers the desired number of multicodes and modulates the modulation code from the SIR value. Select MCS. The required S I IU direct calculation unit 12 generates an S I R table for each multicode number in advance.
この実施の形態 5によれば、 基地局が移動局の所望のマルチコ一ド数 で送信することにより、 セル内干渉を減少することができる効果を奏す る。 産業上の利用可能性  According to the fifth embodiment, the base station transmits with the desired number of multi-codes of the mobile station, thereby achieving an effect of reducing intra-cell interference. Industrial applicability
以上のように、 この発明に係る基地局及び通信システムは、 基地局が 移動局の受信品質をフィ一ドバックし、 基地局が移動局の受信品質に基 づいて変調方式や符号化レー トを適応的に切り替える方式を採用するも のに適している。 As described above, in the base station and the communication system according to the present invention, the base station feeds back the reception quality of the mobile station, and the base station performs the feedback based on the reception quality of the mobile station. It is suitable for adopting a method of adaptively switching the modulation method and the coding rate based on this.

Claims

請 求 の 範 囲 The scope of the claims
1 . 移動局から通信路の品質測定値を受信する受信手段と、 上記受信手 段により受信された品質測定値に応じて変調符号化方式を選択する方式 選択手段と、 上記受信手段により受信された品質測定値と上記方式選択 手段により選択された変調符号化方式における必要最小限の品質値との 差分値を計算し、 その差分値に基づいて上記移動局に送信する拡散変調 信号の送信電力を制御する電力制御手段とを備えた基地局。 1. Receiving means for receiving the quality measurement value of the communication channel from the mobile station, method selection means for selecting a modulation and coding scheme according to the quality measurement value received by the receiving means, The difference between the measured quality value and the minimum required quality value of the modulation and coding scheme selected by the scheme selection means is calculated, and the transmission power of the spread modulation signal transmitted to the mobile station is calculated based on the calculated difference. And a power control means for controlling the power supply.
2 . 方式選択手段は、 受信手段により受信された品質測定値を満足する 変調符号化方式の中で、 品質値が最高の変調符号化方式を選択すること を特徴とする請求の範囲第 1項記載の基地局。 2. The method selecting means, wherein the method selecting means selects a modulation and coding method having the highest quality value among the modulation and coding methods satisfying the quality measurement value received by the receiving means. Base station as described.
3 . 方式選択手段は、 各種の変調符号化方式と品質値の対応関係を示す テーブルを参照して変調符号化方式を選択することを特徴とする請求の 範囲第 2項記載の基地局。 3. The base station according to claim 2, wherein the method selection means selects a modulation and coding method with reference to a table showing a correspondence between various modulation and coding methods and quality values.
4 . 電力制御手段は、 差分値から送信電力オフセッ トを計算して、 デフ オル トの固定送信電力から当該送信電力オフセッ トを減算し、 その減算 結果を拡散変調信号の送信電力とすることを特徴とする請求の範囲第 1 項記載の基地局。 4. The power control means calculates the transmission power offset from the difference value, subtracts the transmission power offset from the default fixed transmission power, and uses the subtraction result as the transmission power of the spread modulation signal. The base station according to claim 1, wherein:
5 . 方式選択手段は、 受信手段が移動局から通信路の品質測定値を受信 する代わりに、 その移動局から変調符号化方式の選択情報を受信すると 、 その選択情報が示す変調符号化方式を選択することを特徴とする請求 の範囲第 1項記載の基地局。 5. When the receiving means receives the modulation coding scheme selection information from the mobile station instead of the communication station quality measurement value from the mobile station, the scheme selecting means selects the modulation coding scheme indicated by the selection information. The base station according to claim 1, wherein the base station is selected.
6 . 電力制御手段は、 受信手段が移動局から送信電力オフセッ トを受信 すると、 その送信電力オフセッ 卜から拡散変調信号の送信電力を決定す ることを特徴とする請求の範囲第 5項記載の基地局。 6. The power control unit according to claim 5, wherein, when the receiving unit receives the transmission power offset from the mobile station, the power control unit determines the transmission power of the spread modulation signal from the transmission power offset. base station.
7 . 方式選択手段は、 受信手段が移動局から移動速度又はドップラー周 波数の測定値を受信すると、 その測定値を考慮して変調符号化方式を選 択することを特徴とする請求の範囲第 1項記載の基地局。 7. The method selecting means, wherein, when the receiving means receives a measured value of the moving speed or the Doppler frequency from the mobile station, the method selecting means selects a modulation and coding method in consideration of the measured value. Base station according to item 1.
8 . 方式選択手段は、 受信手段が移動局から複数種類の品質測定値を受 信すると、 各種の品質測定値を使い分けて変調符号化方式を選択するこ とを特徴とする請求の範囲第 1項記載の基地局。 8. The method selecting means, wherein, when the receiving means receives a plurality of types of quality measurement values from the mobile station, the method selection means selects a modulation and coding method by properly using the various quality measurement values. The base station according to the item.
9 . 方式選択手段は、 受信手段が移動局から品質測定値として S I R値 とブロックエラーレートを受信すると、 初期送信時又は不連続送信時に は S I R値に応じて変調符号化方式を選択し、 連続送信時にはプロック エラーレートに応じて変調符号化方式を選択することを特徴とする請求 の範囲第 8項記載の基地局。 9. When the receiving means receives the SIR value and block error rate as quality measurements from the mobile station, the method selecting means selects the modulation and coding method according to the SIR value at the time of initial transmission or discontinuous transmission, 9. The base station according to claim 8, wherein at the time of transmission, a modulation and coding scheme is selected according to a block error rate.
1 0 . 方式選択手段は、 受信手段が移動局からマルチコード数を受信す ると、 そのマルチコ一ド数を考慮して変調符号化方式を選択することを 特徴とする請求の範囲第 1項記載の基地局。 10. The method selecting means, wherein, when the receiving means receives the number of multi-codes from the mobile station, the method selecting means selects a modulation and coding method in consideration of the number of multi-codes. Base station as described.
1 1 . 通信路の品質値を測定し、 その品質測定値を送信する移動局と、 上記移動局から品質測定値を受信すると、 その品質測定値に応じて変調 符号化方式を選択し、 その品質測定値と当該変調符号化方式における必 要最小限の品質値との差分値を計算し、 その差分値に基づいて上記移動 局に送信する拡散変調信号の送信電力を制御する基地局とを備えた通信 システム。 1 1. The quality value of the communication channel is measured, and the mobile station that transmits the quality measurement value, and when the quality measurement value is received from the mobile station, selects a modulation and coding scheme according to the quality measurement value, and Quality measurements and the required A communication system comprising: a base station that calculates a difference value from a minimum required quality value and controls transmission power of a spread modulation signal to be transmitted to the mobile station based on the difference value.
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