JP2010087634A - Mobile station, wireless base station, and mobile communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately set the number of symbols of a control signal which is multiplexed on a data signal and transmitted according to the modulation system. <P>SOLUTION: A mobile station UE is constituted to acquire parameters about a control signal which is multiplexed on a data signal and transmitted from a wireless base station eNB, and to determine the number of symbols of the control signal, based on the parameters and the modulation system of the data signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile station, a radio base station, and a mobile communication method.

  A communication system that succeeds the wideband code division multiple access (W-CDMA) system, the high-speed downlink packet access (HSDPA) system, the high-speed uplink packet access (HSUPA) system, etc. The term evolution (LTE) system is being studied by the W-CDMA standardization organization 3GPP.

  As a radio access scheme using the LTE scheme, an Orthogonal Frequency Division Multiplexing Access (OFDMA) scheme is used for the downlink, and a single carrier frequency division multiple access (SC-FDMA: Single) is used for the uplink. -It is considered promising that the Carrier Frequency Division Multiple Access) method is used (for example, see Non-Patent Document 1).

  The OFDMA scheme is a multicarrier transmission scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is transmitted on each subcarrier. It can be expected that high-speed transmission can be realized by increasing the frequency utilization efficiency by arranging subcarriers densely while being orthogonal to each other on the frequency axis.

  The SC-FDMA scheme is a single carrier transmission scheme in which a frequency band is divided for each terminal, and transmission is performed using different frequency bands among a plurality of terminals. Since the interference between terminals can be reduced easily and effectively, and the variation in transmission power can be reduced, the SC-FDMA scheme is preferable from the viewpoint of reducing the power consumption of terminals and expanding the coverage.

  In the LTE system, two transmission methods are defined for uplink control signals based on whether or not uplink data signals are transmitted at the transmission timing.

  That is, when an uplink data signal is transmitted, the uplink control signal is transmitted by being multiplexed with the uplink data signal, and when the uplink data signal is not transmitted, Only uplink control signals are transmitted.

  Here, the physical channel to which the uplink control signal in the former case is mapped is PUSCH (Physical Uplink Shared Channel), and the physical channel to which the uplink control signal in the latter case is mapped is PUCCH. (Physical Uplink Control Channel).

  Here, the control signals include Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK Information, and Scheduling Request.

  Hereinafter, an uplink control signal mapped to the PUSCH will be described.

  Here, for example, the number of symbols Q ′ of the HARQ-ACK information is calculated as follows (see Non-Patent Document 2).

Here, O is the number of information bits of HARQ-ACK information, and M _SC ^{PUSCH-current} is the number of PUSCH subcarriers of the subframe.

M _SC ^PUSCH , N _sym ^PUSCH , C, and K _r are parameters obtained from a downlink control signal (PDCCH: Physical Downlink Control Channel) for initial transmission, and more specifically, M _SC ^PUSCH. Is the number of PUSCH subcarriers in the initial transmission, N _sym ^PUSCH is the number of SC-FDMA symbols in PUSCH, C is the number of code blocks segmented in the turbo code, and K _r is the r th The number of bits in the code block.

は、セグメントされた各コードブロックの情報ビット数の総和であり、ほぼＰＵＳＣＨに多重されるデータ信号（ＵＬ-ＳＣＨ）の情報ビット数に等しい。また、Δ_{ｏｆｆｓｅｔ} ^{ＰＵＳＣＨ}は、上位レイヤからシグナリングされるオフセット値である。 here,

Is the total number of information bits of each segmented code block, and is approximately equal to the number of information bits of the data signal (UL-SCH) multiplexed on the PUSCH. Δ _offset ^PUSCH is an offset value signaled from an upper layer.

  In summary, the number of uplink control signal symbols multiplexed on the PUSCH includes the number of control signal information bits, the number of PUSCH subcarriers, the number of PUSCH SC-FDMA symbols, and the number of data signal information bits. And an offset value signaled from an upper layer.

  Meanwhile, the modulation scheme of the uplink control signal multiplexed on the PUSCH is the same as that of the uplink data signal.

  However, when the modulation method of the uplink data signal is 16QAM or 64QAM, the position where the uplink control signal is mapped is within the constellation point having the largest amplitude as shown in FIGS. (See Non-Patent Documents 2 and 3).

As described above, it is possible to improve the reception SIR by transmitting HARQ-ACK Information using only the constellation point having the largest amplitude (the largest signal power).
3GPP TS 36.211 V8.3.0 (May 2008) DRAFT 3GPP TS36.212 V8.4.0 (September 2008), “5.2.2.6 Channel coding of control information” 3GPP TS 36.211 V8.3.0 (May 2008), “5.3.1 Scrambling”

  As described above, the number of uplink control signal symbols multiplexed on PUSCH includes the number of control signal information bits, the number of PUSCH subcarriers, the number of PUSCH SC-FDMA symbols, and the number of data signal information bits. And the offset value signaled from the higher layer.

  On the other hand, as described above, the uplink control signal multiplexed to PUSCH is multiplexed to the constellation point having the largest signal power in the case of 16QAM or 64QAM. This means that the communication quality of the uplink control signal multiplexed on the PUSCH depends on the modulation scheme of the PUSCH data signal.

  That is, since the method for determining the number of symbols of the uplink control signal multiplexed on the PUSCH does not consider the modulation scheme of the PUSCH data signal, the optimum offset value is set for all modulation schemes. There is a problem that can not be.

  In this case, if the offset value optimized for one of all the modulation schemes is used, problems such as deterioration in communication quality or increase in the overhead of control signals occur with respect to the remaining modulation schemes.

  Therefore, the present invention has been made in view of the above-described problems, and a mobile station, a radio base station, and a mobile station that can appropriately set the number of uplink control signal symbols based on a modulation scheme An object is to provide a communication method.

  A first feature of the present invention is a mobile station that communicates with a radio base station, and is configured to receive a parameter for an uplink control signal from the radio base station; A symbol number determining unit configured to determine the number of symbols of the uplink control signal based on the parameter, and transmitting the uplink control signal with the determined number of symbols. The transmitter is configured, and the gist number determining unit is configured to determine the number of symbols based on a modulation scheme.

  In the first aspect of the present invention, the modulation scheme may be a modulation scheme of an uplink shared channel on which the uplink control signal is multiplexed.

  In the first feature of the present invention, the symbol number determining unit increases the number of symbols when the number of bits per symbol in the modulation scheme is small, and the number of bits per symbol in the modulation scheme is large. In this case, the number of symbols may be reduced.

  In the first aspect of the present invention, the parameter acquisition unit is configured to acquire the parameter for each modulation scheme, and the symbol number determination unit is based on the parameter for each modulation scheme, The number of symbols of the uplink control signal may be determined.

  In the first aspect of the present invention, the modulation scheme may be at least one of BPSK, QPSK, 16QAM, and 64QAM.

  In the first aspect of the present invention, the uplink control signal may be at least one of Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK information.

  According to a second aspect of the present invention, there is provided a radio base station that communicates with a mobile station, the radio base station that communicates with the mobile station, wherein a parameter for an uplink control signal is transmitted to the mobile station. A parameter notification unit configured to notify, a symbol number determination unit configured to determine the number of symbols of the uplink control signal based on the parameter, and the determined number of symbols. A receiving unit configured to receive the transmitted uplink control signal, and the symbol number determining unit is configured to determine the number of symbols based on a modulation scheme This is the gist.

  In the second aspect of the present invention, the modulation scheme may be a modulation scheme of an uplink shared channel on which the control signal is multiplexed.

  In the second feature of the present invention, the symbol number determination unit increases the number of symbols when the number of bits per symbol in the modulation scheme is small, and the number of bits per symbol in the modulation scheme is large. In this case, the number of symbols may be reduced.

  In the second aspect of the present invention, the parameter notification unit is configured to notify the parameter for each modulation scheme, and the symbol number determination unit is configured to perform the parameter determination based on the parameter for each modulation scheme. The number of symbols of the uplink control signal may be determined.

  In the second aspect of the present invention, the modulation scheme may be at least one of BPSK, QPSK, 16QAM, and 64QAM.

  In the second aspect of the present invention, the uplink control signal may be at least one of Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, and HARQ-ACK information.

  According to a third aspect of the present invention, there is provided a mobile communication method for communicating between a radio base station and a mobile station, wherein the radio base station provides a parameter for an uplink control signal to the mobile station. , Step B in which the mobile station and the mobile station determine the number of symbols for the control signal of the uplink signal based on the parameter, and the mobile station to the radio base station On the other hand, the method includes a step C of transmitting the uplink control signal with the determined number of symbols, and in the step B, the number of symbols is determined based on a modulation scheme. .

  As described above, according to the present invention, it is possible to provide a mobile station, a radio base station, and a mobile communication method that can appropriately set the number of symbols of an uplink control signal based on a modulation scheme. Can do.

(Configuration of mobile communication system according to the first embodiment of the present invention)
The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 3, the mobile communication system according to the present embodiment is an LTE mobile communication system. In such a mobile communication system, “OFDMA (Orthogonal Frequency Division Multiplexing Access)” is applied for the downlink and “SC-FDMA (Single-Carrier Frequency Multiple)” is used for the uplink as the radio access method. Application is under consideration.

  The OFDMA scheme is a scheme in which a specific frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is transmitted on each frequency band. According to the OFDM scheme, high-speed transmission can be realized and frequency utilization efficiency can be improved by arranging subcarriers closely without interfering with each other while partially overlapping on the frequency axis.

  Further, the SC-FDMA scheme can reduce interference between a plurality of mobile stations UE by dividing a specific frequency band and transmitting using a different frequency band between the plurality of mobile stations UE. Transmission method. According to the SC-FDMA scheme, since the variation in transmission power is small, it is possible to realize low power consumption and wide coverage of the mobile station UE.

  Further, in the mobile communication system according to the present embodiment, the radio base station eNB transmits a downlink control signal via the physical downlink control channel PDCCH, and downlink data via the physical downlink shared data channel PDSCH (Physical Downlink Shared Channel). It is configured to transmit a signal.

  On the other hand, in the mobile communication system according to the present embodiment, the mobile station UE is configured to transmit an uplink data signal via a physical uplink shared data channel PUSCH (Physical Uplink Shared Channel).

  When an uplink control signal is transmitted in a subframe (TTI: Transmission Time Interval) in which the physical uplink shared data channel PUSCH (Physical Uplink Shared Channel) is transmitted, the uplink control signal is transmitted to the PUSCH. To be mapped. That is, the uplink control signal is multiplexed with the uplink data signal and transmitted.

  Here, the uplink control signal includes Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK Information, and Scheduling Request.

  The PUSCH, the Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, when Rand Indicator, HARQ-ACK information, Scheduling Request is mapped, the Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, At least one of Rand Indicator, HARQ-ACK information, Scheduling Request may be mapped, or All may be mapped.

  As illustrated in FIG. 4, the mobile station UE includes a parameter acquisition unit 11, a symbol number determination unit 12, a transmission management unit 13, and an uplink signal transmission unit 14.

  The parameter acquisition unit 11 is configured to acquire parameters for uplink control signals from the radio base station eNB. The parameter acquisition unit 11 is configured to notify the symbol number determination unit 12 of parameters for the uplink control signal.

  The parameter for the uplink control signal may be notified as a part of broadcast information or as a part of information in RRC Signaling individually notified to each mobile station UE in the cell. You may be notified.

  Here, the parameter for the uplink control signal may be a parameter for determining the number of symbols of the uplink control signal mapped to the PUSCH.

More specifically, the parameter for the uplink control signal may be an offset value for determining the number of symbols of the uplink control signal mapped to the PUSCH. The offset value may be described as Δ _offset ^PUSCH .

The symbol number determination unit 12 is configured to receive the parameter Δ _offset ^PUSCH for the uplink control signal from the parameter acquisition unit 11. Further, the symbol number determination unit 12 is configured to receive the following parameters from the transmission management unit 13.

O: Number of information bits of uplink control signal M _SC ^PUSCH : Number of PUSCH subcarriers N _sym ^PUSCH : Number of SC-FDMA symbols of PUSCH C: Number of code blocks segmented in turbo code K _r : r-th code block Modulation: PUSCH modulation method (Modulation Scheme)

  Then, the symbol number determination unit 12 calculates the number of symbols for the uplink control signal based on the parameters as follows.

  Alternatively, the symbol number determination unit 12 may calculate the number of symbols for the uplink control signal as follows.

Here, M _sc ^{PUSCH-current} is the number of PUSCH subcarriers in the subframe. The M _sc ^{PUSCH-current} may be notified from the transmission management unit 13.

  The uplink control signal may be an uplink control signal mapped to PUSCH. That is, the uplink control signal may be an uplink control signal multiplexed with a data signal.

  Here, f (MODULATION) is a function that uses a PUSCH modulation scheme as an argument.

  That is, the symbol number determination unit 12 determines the number of symbols of the uplink control signal based on the modulation scheme. In other words, the symbol number determination unit 12 calculates the number of symbols for the uplink control signal using an expression including information on the modulation scheme.

  More specifically, f (MODULATION) may be described as follows.

f (MODULATION) = 1 / x × G (y)
x: Number of bits per symbol (BSPK: 1, QPSK: 2, 16QAM: 4, 64QAM: 6)

  Here, G (y) is an arbitrary function, and may be an arbitrary fixed value or a value determined by an arbitrary logic. That is, in the calculation formula for determining the number of symbols of the uplink control signal, the number of bits per symbol in each modulation scheme may be included in the denominator.

  In this case, when the number of bits per symbol of the modulation scheme is large, the number of symbols of the uplink control signal is calculated to be small, and when the number of bits per symbol of the modulation scheme is small, the uplink control signal A large number of symbols is calculated.

  More specifically, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 64QAM, and may be set to be large when the modulation scheme is 16QAM. .

  Alternatively, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 16QAM, and may be set to be large when the modulation scheme is QPSK.

  Alternatively, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 64QAM or 16QAM, and may be set to be large when the modulation scheme is QPSK.

In this way, by calculating the number of symbols of the uplink control signal based on the modulation scheme, one modulation parameter, that is, the parameter Δ _offset ^PUSCH for the uplink control signal is used for each modulation scheme. It is possible to calculate the optimum number of uplink control signal symbols.

  Or more specifically, f (MODULATION) may be described as follows.

f (MODULATION) = 1 / H (x) × G (y)
x: Number of bits per symbol (BSPK: 1, QPSK: 2, 16QAM: 4, 64QAM: 6)
H (x): a monotonically increasing function with respect to x

  Here, G (y) is an arbitrary function, and may be an arbitrary fixed value or a value determined by an arbitrary logic. That is, in the calculation formula for determining the number of symbols of the uplink control signal, a function that monotonously increases with respect to the number of bits per symbol in each modulation scheme may be included in the denominator.

  In this case, when the number of bits per symbol of the modulation scheme is large, the number of symbols of the uplink control signal is calculated to be small, and when the number of bits per symbol of the modulation scheme is small, the uplink control signal A large number of symbols is calculated.

In this way, by calculating the number of symbols of the uplink control signal based on the modulation scheme, one modulation parameter, that is, the parameter Δ _offset ^PUSCH for the uplink control signal is used for each modulation scheme. It is possible to calculate the optimum number of uplink control signal symbols.

H (x) may be, for example, a function composed of at least one of a ^x that is an exponential function, Log _a (x) that is _a logarithmic function, and a × x ^b . Further, H (x ′) may be calculated after correction such as x ′ = a × x + C is applied to the value of x. Alternatively, H (x ′) may be calculated after the process of converting the true value (x) to the dB value (x ′) is applied. Alternatively, H (x ′) may be calculated after the process of converting the dB value (x) to the true value (x ′) is applied. Here, a, b, and c are arbitrary coefficients.

  Or more specifically, f (MODULATION) may be described as follows.

f (MODULATION) = 1 × H (x) × G (y)
x: Number of bits per symbol (BSPK: 1, QPSK: 2, 16QAM: 4, 64QAM: 6)
H (x): monotonically decreasing function for x

  Here, G (y) is an arbitrary function, and may be an arbitrary fixed value or a value determined by an arbitrary logic. That is, in the calculation formula for determining the number of symbols of the uplink control signal, a function that monotonously decreases with respect to the number of bits per symbol in each modulation method may be included in the numerator.

  In this case, when the number of bits per symbol of the modulation scheme is large, the number of symbols of the uplink control signal is calculated to be small, and when the number of bits per symbol of the modulation scheme is small, the uplink control signal A large number of symbols is calculated.

  That is, the number of symbols of the uplink control signal is set to be small when the number of bits per symbol of the modulation scheme is large, and is set to be large when the number of bits per symbol of the modulation scheme is small. It may be configured.

  More specifically, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 64QAM, and may be set to be large when the modulation scheme is 16QAM. .

  Alternatively, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 16QAM, and may be set to be large when the modulation scheme is QPSK.

  Alternatively, the number of symbols of the uplink control signal may be set to be small when the modulation scheme is 64QAM or 16QAM, and may be set to be large when the modulation scheme is QPSK.

In this way, by calculating the number of symbols of the uplink control signal based on the modulation scheme, one modulation parameter, that is, the parameter Δ _offset ^PUSCH for the uplink control signal is used for each modulation scheme. It is possible to calculate the optimum number of uplink control signal symbols.

Note that H (x) may be, for example, a function composed of at least one of a− ^x and −a × ^xb that are exponential functions. Further, H (x ′) may be calculated after correction such as x ′ = a × x + c is applied to the value of x. Alternatively, H (x ′) may be calculated after the process of converting the true value (x) to the dB value (x ′) is applied. Alternatively, H (x ′) may be calculated after the process of converting the dB value (x) to the true value (x ′) is applied. Here, a, b, and c are arbitrary coefficients.

  Alternatively, the symbol number determination unit 12 may calculate the number of symbols for the uplink control signal based on the parameters as follows.

In this case, the parameter _delta ^{offset PUSCH} for uplink control signal regarding QPSK is notified from the radio base station eNB, the parameter _delta ^{offset PUSCH} for uplink control signal relates to 16QAM or 64QAM, uplink relating to the QPSK This is a value obtained by correcting the parameter Δ _offset ^PUSCH for the control signal.

  In the above example, “−3” is a correction parameter for 16QAM, and “−4” is a correction parameter for 64QAM. Further, “−3” and “−4” are examples, and other values may be used.

Alternatively, in the above example, the parameter Δ _offset ^PUSCH for the uplink control signal related to QPSK is notified from the radio base station eNB, but instead, the parameter Δ _offset ^PUSCH for the uplink control signal related to 16 QAM is used ^. Is reported from the radio base station eNB, and the parameter Δ _offset ^PUSCH for the uplink control signal related to QPSK or 64QAM may be a value obtained by correcting the parameter Δ _offset ^PUSCH for the uplink control signal related to 16 QAM.

  In other words, the symbol number determination unit 12 may calculate the number of symbols for the uplink control signal based on the parameter as follows.

Here, offset _MOD is a parameter for correcting the difference in quality _depending on the modulation method. That is, the symbol number determination unit 12 determines the number of symbols for the uplink control signal based on the parameter Δ _offset ^PUSCH for the uplink control signal and the parameter offset _MOD set for each modulation scheme. To do.

  More specifically, for example, a parameter for correcting a difference in quality due to the modulation scheme may be set as follows.

For QPSK: offset _MOD = 3 dB
For 16QAM: offset _MOD = 0 dB
For 64QAM: offset _MOD = -1 dB

  Note that the values such as 3 dB, 0 dB, and −1 dB are examples, and other values may be used.

  Then, the symbol number determination unit 12 notifies the uplink signal transmission unit 14 of the calculated symbol number for the uplink control signal.

  The transmission management unit 13 acquires information about PUSCH to be transmitted in the subframe, and notifies the information to the symbol number determination unit 12. The information may be acquired, for example, by receiving a downlink control signal, PDCCH.

  The PDCCH transmits a UL Scheduling Grant for uplink data signals (UL-SCH, PUSCH) and a DL Scheduling Grant for downlink data signals (DL-SCH, PDSCH).

  The UL Scheduling Grant and the DL Scheduling Grant may be collectively referred to as a Downlink Scheduling Information (DCI).

  Here, the information is more specifically the following parameters.

O: Number of information bits of uplink control signal M _SC ^PUSCH : Number of PUSCH subcarriers N _sym ^PUSCH : Number of SC-FDMA symbols of PUSCH C: Number of code blocks segmented in turbo code K _r : r-th code block Modulation: PUSCH modulation method (Modulation Scheme)

The M _SC ^PUSCH may be the number of PUSCH subcarriers in the initial transmission, or may be the number of PUSCH subcarriers transmitted in the subframe. Alternatively, M _sym ^PUSCH may be the number of SC-FDMA symbols of PUSCH in the initial transmission, or the number of SC-FDMA symbols of PUSCH transmitted in the subframe.

  In addition, Modulation may be a PUSCH (data signal) modulation scheme (Modulation Scheme) in initial transmission, or may be the number of PUSCH (data signal) subcarriers transmitted in the subframe.

  Here, the subframe is a subframe (Current Subframe) in which the PUSCH and an uplink control signal mapped to the PUSCH are transmitted.

  Also, the transmission management unit 13 acquires information necessary for transmission of the uplink signal and notifies the uplink signal transmission unit 14 of the information. Here, the information necessary for transmission of the uplink signal includes, for example, information measured in the mobile station UE, information notified by the downlink control signal PDCCH described above, and the like.

  The uplink signal transmission unit 14 receives the number of symbols for the uplink control signal from the symbol number determination unit 12. The uplink signal transmission unit 14 receives information necessary for transmission of the uplink signal from the transmission management unit 13.

  Then, the uplink signal transmission unit 14, based on the number of symbols for the uplink control signal and information necessary for transmission of the uplink signal, an uplink data signal and an uplink control signal, Send.

  Here, the uplink data signal and the uplink control signal are multiplexed, mapped to PUSCH, and transmitted.

  As illustrated in FIG. 5, the radio base station eNB includes a parameter notification unit 21, a symbol number determination unit 22, a reception management unit 23, and an uplink signal reception unit 24.

  The parameter notification unit 21 is configured to notify a parameter for an uplink control signal to the mobile station UE. The parameter notifying unit 21 is configured to notify the symbol number determining unit 22 of parameters for the uplink control signal.

  The parameter for the uplink control signal may be notified as a part of broadcast information or as a part of information in RRC Signaling individually notified to each mobile station UE in the cell. You may be notified.

Here, the parameter for the uplink control signal may be a parameter for determining the number of symbols of the uplink control signal mapped to the PUSCH. More specifically, the parameter for the uplink control signal may be an offset value for determining the number of symbols of the uplink control signal mapped to the PUSCH. The offset value may be described as Δ _offset ^PUSCH .

The symbol number determination unit 22 is configured to receive the parameter Δ _offset ^PUSCH for the uplink control signal from the parameter acquisition unit 21. Further, the symbol number determination unit 22 is configured to receive the following parameters from the reception management unit 23.

O: Number of information bits of uplink control signal M _SC ^PUSCH : Number of PUSCH subcarriers N _sym ^PUSCH : Number of SC-FDMA symbols of PUSCH C: Number of code blocks segmented in turbo code K _r : r-th code block Modulation: PUSCH modulation method (Modulation Scheme)

  The symbol number determination unit 22 is configured to calculate the number of symbols for the uplink control signal based on the parameters received from the parameter acquisition unit 21 and the reception management unit 23. ing.

  Note that the method for calculating the number of symbols for the uplink control signal in the symbol number determination unit 22 is the same as the method for calculating the number of symbols for the uplink control signal in the symbol number determination unit 12, and therefore the description thereof is omitted. Is omitted.

  The symbol number determination unit 22 is configured to notify the uplink signal reception unit 14 of the calculated symbol number for the uplink control signal.

  The reception management unit 23 is configured to acquire information on PUSCH received in the subframe and notify the information to the symbol number determination unit 22.

  The information may be information obtained from, for example, a control signal in the downlink, a parameter notified to the mobile station UE by PDCCH. The details of the information are the same as the information in the description related to the transmission management unit 13 described above, and thus the description thereof is omitted.

  Further, the reception management unit 23 is configured to acquire information necessary for reception of the uplink signal and notify the uplink signal reception unit 24 of the information. Here, the information necessary for receiving the uplink signal includes, for example, information notified to the UE by the above-described downlink control signal PDCCH.

  The uplink signal reception unit 24 is configured to receive the number of symbols for the uplink control signal from the symbol number determination unit 22. The uplink signal receiving unit 24 is configured to receive information necessary for reception of the uplink signal from the reception managing unit 23.

  Then, the uplink signal receiving unit 24, based on the number of symbols for the uplink control signal and information necessary for receiving the uplink signal, an uplink data signal and an uplink control signal, Is configured to receive.

  Here, the uplink data signal and the uplink control signal are multiplexed, mapped to PUSCH, and transmitted.

  The uplink control signals described above include Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK information, and Scheduling.

For example, if the uplink control signal is HARQ-ACK information, O corresponds to the number of information bits of HARQ-ACK information, and the parameter Δ _offset ^PUSCH for the uplink control signal is HARQ- This corresponds to a parameter related to ACK information.

Alternatively, when the uplink control signal is a Rank Indicator, O corresponds to the number of information bits of the Rank Indicator, and the parameter Δ _offset ^PUSCH for the uplink control signal corresponds to a parameter related to the Rank Indicator. To do.

Alternatively, when the uplink control signal is the Channel Quality Control Information, O corresponds to the number of information bits of the Channel Quality Control Information, and the parameter Δ _offset ^PUSCH for the uplink control signal is the Channel Queuing This corresponds to the parameter related to Control Information.

  Note that the Channel Quality Control Information may include a Channel Quality Indicator and a Precoding Matrix Indicator.

  Alternatively, when the uplink control signal is Channel Quality Control Information, the number of symbols may be determined by the following equation.

  Here, L is the number of bits of CRC assigned to Channel Quality Control Information. Since other parameters and functions are the same as those in the above-described formula, description thereof will be omitted.

(Operation of the mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 6, the operation of the mobile communication system according to the first embodiment of the present invention will be described.

  In step S302, the radio base station eNB notifies a parameter for an uplink control signal to the mobile station UE. At this time, the mobile station UE receives parameters for the uplink control signal from the radio base station eNB.

  In step S304, the radio base station eNB and the mobile station UE determine the number of symbols of the uplink control signal based on the parameter for the uplink control signal and the modulation scheme.

  In addition, since the description regarding the determination method of the symbol number of an uplink control signal is equivalent to the description regarding the symbol number determination part 12 of the mobile station UE mentioned above, it abbreviate | omits.

  In step S306, the mobile station UE transmits the uplink control signal. At this time, the radio base station eNB receives the uplink control signal transmitted from the mobile station UE. In this case, the number of symbols of the uplink control signal is the value calculated in step S304.

  The uplink control signal includes Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK information, and Scheduling Re- cord.

  Further, the uplink control signal is an uplink control signal mapped to PUSCH. That is, the uplink control signal is an uplink control signal that is multiplexed with a data signal and transmitted.

(Operations and effects of the mobile communication system according to the first embodiment of the present invention)
According to the mobile communication system according to the first embodiment of the present invention, by setting one offset value (that is, a parameter for an uplink control signal), an optimum uplink for all modulation schemes is set. Since the number of symbols of the control signal is determined, as a result, stable communication quality and reduction of overhead can be realized.

(Modification 1)
In the first modification of the present invention, the parameter acquisition unit 11 and the symbol number determination unit 12 in the mobile station UE, the parameter notification unit 21 and the symbol number 22 in the radio base station eNB are the mobile station UE in the first embodiment described above. Is different from the parameter notifying unit 21 and the symbol number 22 in the radio base station eNB. Therefore, in the following, the parameter acquiring unit 11 and the symbol number determining unit 12 in the mobile station UE, the radio base station The parameter notification unit 21 and the number of symbols 22 in the eNB will be described.

  The description of each functional unit other than the parameter acquisition unit 11 and the symbol number determination unit 12 in the mobile station UE, and the parameter notification unit 21 and the symbol number 22 in the radio base station eNB is the same as the description in the first embodiment, and is omitted. To do.

  The parameter acquisition unit 11 is configured to acquire parameters for uplink control signals from the radio base station eNB for each modulation scheme. The parameter acquisition unit 11 is configured to notify the symbol number determination unit 12 of parameters for the uplink control signal for each modulation scheme. Examples of the modulation scheme include BPSK, QPSK, 16QAM, and 64QAM.

  The parameter for the uplink control signal for each modulation scheme may be notified as part of the broadcast information, or in the RRC Signaling individually notified to each mobile station UE in the cell. You may be notified as a part of information.

  Here, the parameter for the uplink control signal for each modulation scheme may be a parameter for determining the number of symbols of the uplink control signal mapped to the PUSCH.

  More specifically, the parameter for the uplink control signal for each modulation scheme may be an offset value for determining the number of symbols of the uplink control signal mapped to the PUSCH.

The offset value may be described as Δ _offset ^{PUSCH, MODULATION} . More specifically, for example, QPSK, 16QAM, wherein the offset values for 64QAM, ^{_{respectively, Δ offset PUSCH, QPSK, Δ}} offset PUSCH, 16QAM, Δ offset PUSCH, it may be described as ^64QAM.

The symbol number determination unit 12 is configured to receive a parameter Δ _offset ^PUSCH for the uplink control signal for each modulation scheme from the parameter acquisition unit 11.

More specifically, the symbol number determination unit 12 uses Δ _offset ^{PUSCH, QPSK} , Δ _offset ^{PUSCH, 16QAM} , Δ _offset ^{PUSCH, 64QAM} as parameters for the uplink control signals related to QPSK, 16QAM, and 64QAM, respectively. You may receive.

  Further, the symbol number determination unit 12 is configured to receive the following parameters from the transmission management unit 13.

O: Number of information bits of uplink control signal M _SC ^PUSCH : Number of PUSCH subcarriers N _sym ^PUSCH : Number of SC-FDMA symbols of PUSCH C: Number of code blocks segmented in turbo code K _r : r-th code block Modulation: PUSCH modulation method (Modulation Scheme)

  Then, the symbol number determination unit 12 calculates the number of symbols for the uplink control signal based on the parameters as follows.

  Here, MODULATION is set to values such as QPSK, 16QAM, and 64QAM.

  Alternatively, the number of symbols for the uplink control signal may be calculated as follows.

Here, M _sc ^{PUSCH-current} is the number of PUSCH subcarriers in the subframe. The M _sc ^{PUSCH-current} may be notified from the transmission management unit 13. Also, MODULATION is set to values such as QPSK, 16QAM, and 64QAM, for example.

  The uplink control signal may be an uplink control signal mapped to PUSCH. That is, the uplink control signal may be an uplink control signal multiplexed with a data signal.

  Since the above formula includes parameters for the uplink control signal set for each modulation scheme, the symbol number determination unit 12 determines the number of symbols of the uplink control signal based on the modulation scheme. decide. In other words, the symbol number determination unit 12 is configured to calculate the number of symbols for the uplink control signal using an expression including information on the modulation scheme.

  As will be described later, the parameter for the uplink control signal for each modulation scheme is set to a small value (for example, 8 dB) when the number of bits per symbol of the modulation scheme is large. When the number of bits per symbol is small, a large value (eg, 11 dB) may be set.

  More specifically, the parameter for the uplink control signal is set to a small value (for example, 7 dB) when the modulation method is 64QAM, and is set to a large value (for example, when the modulation method is 16QAM). , 8 dB) may be set.

  Alternatively, the parameter for the uplink control signal is set to a small value (for example, 8 dB) when the modulation method is 16QAM, and is set to a large value (for example, 11 dB) when the modulation method is QPSK. It may be configured to be set.

  Alternatively, the parameter for the uplink control signal is set to a small value (for example, 8 dB) when the modulation method is 64QAM or 16QAM, and is set to a large value (for example, 11 dB) when the modulation method is QPSK. ) May be set.

  Note that the parameters such as 7 dB, 8 dB, and 11 dB described above are examples, and other values may be used.

In this way, by calculating the number of symbols of the uplink control signal based on the modulation scheme, that is, the parameters notified for each modulation scheme, that is, the above-described parameters Δ _offset ^{PUSCH, QPSK} , Δ _offset ^{PUSCH, Based on 16QAM} , Δ _offset ^{PUSCH, and 64QAM} , it is possible to calculate the optimum number of symbols of the uplink control signal for each modulation scheme.

  The symbol number determination unit 12 is configured to notify the uplink signal transmission unit 14 of the calculated symbol number for the uplink control signal.

  The parameter notification unit 21 is configured to notify the mobile station UE of a parameter for an uplink control signal for each modulation scheme. Also, the parameter notification unit 21 is configured to notify the symbol number determination unit 22 of parameters for the uplink control signal for each modulation scheme.

  The parameter for the uplink control signal for each modulation scheme may be notified as part of the broadcast information, or in the RRC Signaling individually notified to each mobile station UE in the cell. You may be notified as a part of information.

  Here, the parameter for the uplink control signal for each modulation scheme may be a parameter for determining the number of symbols of the uplink control signal mapped to the PUSCH.

  More specifically, the parameter for the uplink control signal for each modulation scheme may be an offset value for determining the number of symbols of the uplink control signal mapped to the PUSCH.

The offset value may be described as Δ _offset ^{PUSCH, MODULATION} . More specifically, for example, QPSK, 16QAM, wherein the offset values for 64QAM, ^{_{respectively, Δ offset PUSCH, QPSK, Δ}} offset PUSCH, 16QAM, Δ offset PUSCH, it may be described as ^64QAM.

  The parameter notification unit 21 sets a small value (for example, 8 dB) when the number of bits per symbol of the modulation scheme is large for the parameter for the uplink control signal for each modulation scheme. However, when the number of bits per symbol of the modulation scheme is small, a large value (for example, 11 dB) may be set.

  More specifically, the parameter for the uplink control signal is set to a small value (for example, 7 dB) when the modulation method is 64QAM, and is set to a large value (for example, when the modulation method is 16QAM). , 8 dB) may be set.

  Alternatively, the parameter for the uplink control signal is set to a small value (for example, 8 dB) when the modulation method is 16QAM, and is set to a large value (for example, 11 dB) when the modulation method is QPSK. It may be configured to be set.

  Alternatively, the parameter for the uplink control signal is set to a small value (for example, 8 dB) when the modulation method is 64QAM or 16QAM, and is set to a large value (for example, 11 dB) when the modulation method is QPSK. ) May be set.

  Note that the parameters such as 7 dB, 8 dB, and 11 dB described above are examples, and other values may be used.

  Thus, the parameters for the uplink control signal are set based on the modulation scheme, and as a result, the number of symbols of the uplink control signal is calculated based on the modulation scheme.

That is, based on the parameters notified for each modulation scheme, that is, the above-described parameters Δ _offset ^{PUSCH, QPSK} , Δ _offset ^{PUSCH, 16QAM} , Δ _offset ^{PUSCH, 64QAM} , the optimum number of symbols for the uplink control signal for each modulation scheme Can be calculated.

The symbol number determination unit 22 is configured to receive parameters Δ _offset ^{PUSCH and MODULATION} for uplink control signals for each modulation scheme from the parameter acquisition unit 21.

More specifically, the symbol number determination unit 22 uses Δ _offset ^{PUSCH, QPSK} , Δ _offset ^{PUSCH, 16QAM} , Δ _offset ^{PUSCH, and 64QAM} as parameters for the uplink control signals related to QPSK, 16QAM, and 64QAM, respectively. You may receive.

  Further, the symbol number determination unit 22 is configured to receive the following parameters from the reception management unit 23.

O: Number of information bits of uplink control signal M _SC ^PUSCH : Number of PUSCH subcarriers N _sym ^PUSCH : Number of SC-FDMA symbols of PUSCH C: Number of code blocks segmented in turbo code K _r : r-th code block Modulation: PUSCH modulation method (Modulation Scheme)

  The symbol number determination unit 22 is configured to calculate the number of symbols for the uplink control signal based on the parameters received from the parameter acquisition unit 21 and the reception management unit 23.

  Note that the method for calculating the number of symbols for the uplink control signal in the symbol number determination unit 22 is the same as the method for calculating the number of symbols for the uplink control signal in the symbol number determination unit 12, and therefore the description thereof is omitted. Is omitted.

  The symbol number determination unit 22 is configured to notify the uplink signal reception unit 14 of the calculated symbol number for the uplink control signal.

  As can be seen from this example, the mobile communication system according to the present modification is configured such that the offset values for determining the number of symbols of the uplink control signal mapped to the PUSCH related to each modulation scheme are different. .

In the above-described example, parameters for the uplink control signal, Δ _offset ^{PUSCH, QPSK} , Δ _offset ^{PUSCH, 16QAM} , Δ _offset ^{PUSCH, and 64QAM} are defined for each of QPSK, 16QAM, and 64QAM. Alternatively, parameters for uplink control signals related to QPSK, Δ _offset ^{PUSCH, QPSK,} and parameters for uplink control signals related to 16QAM / 64QAM, Δ _offset ^{PUSCH, 16/64 QAM} may be set. Good.

Alternatively, parameters Δ _offset ^{PUSCH and QPSK / 16QAM} for uplink control signals related to QPSK and 16QAM, and parameters for uplink control signals related to ^{64 QAM} and Δ _offset ^{PUSCH and 64QAM} may be set.

(Operation of the mobile communication system according to the first modification of the present invention)
With reference to FIG. 7, the operation of the mobile communication system according to the first modification of the present invention will be described.

  In step S402, the radio base station eNB notifies the mobile station UE of a parameter for the uplink control signal for each modulation scheme.

  For example, QPSK and 16QAM exist as the modulation schemes, and the radio base station eNB may notify the mobile station UE of parameters for uplink control signals related to QPSK and 16QAM, respectively. At this time, the mobile station UE receives parameters for the uplink control signal for each modulation scheme from the radio base station eNB.

  In step S404, it is determined whether the modulation method is QPSK or 16QAM. If the modulation method is QPSK (step S404: YES), the operation proceeds to step S406. If the modulation method is not QPSK (if 16QAM) (step S404: NO), the operation is performed in step S408. Proceed to

  In step S406, the radio base station eNB and the mobile station UE determine the number of symbols of the uplink control signal based on the parameter for the uplink control signal related to QPSK.

  In addition, since the description regarding the determination method of the symbol number of an uplink control signal is equivalent to the description regarding the symbol number determination part 12 of the mobile station UE mentioned above, it is abbreviate | omitted.

  In step S408, the radio base station eNB and the mobile station UE determine the number of symbols of the uplink control signal based on parameters for the uplink control signal related to 16QAM.

  In addition, since the description regarding the determination method of the symbol number of an uplink control signal is equivalent to the description regarding the symbol number determination part 12 of the mobile station UE mentioned above, it is abbreviate | omitted.

  In step S410, the mobile station UE transmits the uplink control signal. At this time, the radio base station eNB receives the uplink control signal transmitted from the mobile station UE. In this case, the number of symbols of the uplink control signal is the value calculated in step S406 or step S408.

  In steps S402 to S410 described above, there are two types of modulation schemes, QPSK and 16QAM, but the same control is performed when there are three types of QPSK, 16QAM, and 64QAM instead. .

  The uplink control signals include Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK Information, and Scheduling Re- cord.

  Further, the uplink control signal is an uplink control signal mapped to PUSCH. That is, the uplink control signal is an uplink control signal that is multiplexed with a data signal and transmitted.

  In the first embodiment and the modification described above, when the number of bits per symbol of the modulation scheme is large, the number of symbols of the uplink control signal is calculated to be small, and the number of symbols per symbol of the modulation scheme is calculated. Although an example in which the number of symbols of the uplink control signal is large when the number of bits is small has been shown, instead, when the number of bits per symbol of the modulation scheme is large, the symbol of the uplink control signal When the number is calculated large and the number of bits per symbol of the modulation scheme is small, the number of symbols of the uplink control signal may be calculated small.

  That is, more specifically, the number of symbols of the uplink control signal is set to be large when the modulation scheme is 64QAM, and is set to be small when the modulation scheme is 16QAM. Also good.

  Alternatively, the number of symbols of the uplink control signal may be set to be large when the modulation scheme is 16QAM, and may be set to be small when the modulation scheme is QPSK.

  Alternatively, the number of symbols of the uplink control signal may be set to be large when the modulation scheme is 64QAM or 16QAM, and may be set to be small when the modulation scheme is QPSK.

  When the number of bits per symbol of the above modulation scheme is large, the number of symbols of the uplink control signal is calculated to be large, and when the number of bits per symbol of the modulation scheme is small, the symbol of the uplink control signal The effect of calculating a small number will be described below.

  For example, when the number of bits per symbol of the modulation scheme is large, it is considered that the radio quality between the mobile station UE and the radio base station eNB is good, and the achieved throughput (transmission speed) is a high value. . In this case, by setting the communication quality of the control signal to a better value, it is possible to reduce the deterioration of the throughput due to the error of the control signal.

  On the other hand, when the number of bits per symbol of the modulation scheme is small, it is considered that the radio quality between the mobile station UE and the radio base station eNB is not good, and the degradation of the throughput due to a control signal error is small. . In this case, it is possible to reduce the overhead of the control signal by reducing the number of symbols of the control signal.

  Note that the operations of the radio base station eNB and the mobile station UE described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. .

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the radio base station eNB or the mobile station UE. Further, the storage medium and the processor may be provided as a discrete component in the radio base station eNB or the mobile station UE.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

It is a figure which shows the constellation point of HARQ-ACK information in 16QAM. It is a figure which shows the constellation point of HARQ-ACK information in 64QAM. 1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. FIG. 3 is a functional block diagram of a radio base station according to the first embodiment of the present invention. 3 is a flowchart showing an operation of the mobile communication system according to the first embodiment of the present invention. It is a flowchart which shows operation | movement of the mobile communication system which concerns on the modification 1 of this invention.

Explanation of symbols

UE ... mobile station 11 ... parameter acquisition unit 12 ... symbol number determination unit 13 ... transmission management unit 14 ... uplink signal transmission unit eNB ... radio base station 21 ... parameter notification unit 22 ... symbol number determination unit 23 ... reception management unit 24 ... uplink Signal receiver

Claims (13)

A mobile station that communicates with a radio base station,
A parameter acquisition unit configured to be notified of parameters for an uplink control signal from the radio base station;
A number-of-symbol determination unit configured to determine the number of symbols of the uplink control signal based on the parameter;
A transmission unit configured to transmit the uplink control signal with the determined number of symbols, and
The mobile station, wherein the symbol number determination unit is configured to determine the number of symbols based on a modulation scheme.   The mobile station according to claim 1, wherein the modulation scheme is a modulation scheme of an uplink shared channel on which the uplink control signal is multiplexed.   The symbol number determination unit increases the number of symbols when the number of bits per symbol in the modulation scheme is small, and decreases the number of symbols when the number of bits per symbol in the modulation scheme is large. The mobile station according to claim 1, wherein the mobile station is configured as described above. The parameter acquisition unit is configured to acquire the parameter for each modulation scheme,
The mobile station according to claim 1, wherein the symbol number determination unit is configured to determine the number of symbols of the uplink control signal based on the parameter for each modulation scheme.   The mobile station according to claim 1, wherein the modulation scheme is at least one of BPSK, QPSK, 16QAM, and 64QAM.   The uplink control signal is at least one of Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK information, and Scheduling Request. . A radio base station that communicates with a mobile station,
A parameter notifying unit configured to notify the mobile station of a parameter for an uplink control signal;
A number-of-symbol determination unit configured to determine the number of symbols of the uplink control signal based on the parameter;
A receiving unit configured to receive the uplink control signal transmitted with the determined number of symbols,
The radio base station, wherein the symbol number determination unit is configured to determine the number of symbols based on a modulation scheme.   The radio base station according to claim 7, wherein the modulation scheme is a modulation scheme of an uplink shared channel on which the control signal is multiplexed.   The symbol number determination unit increases the number of symbols when the number of bits per symbol in the modulation scheme is small, and decreases the number of symbols when the number of bits per symbol in the modulation scheme is large. The radio base station according to claim 7, configured as described above. The parameter notification unit is configured to notify the parameter for each modulation scheme,
8. The radio base station according to claim 7, wherein the symbol number determination unit is configured to determine the number of symbols of the uplink control signal based on the parameter for each modulation scheme. .   The radio base station according to claim 7, wherein the modulation scheme is at least one of BPSK, QPSK, 16QAM, and 64QAM.   The uplink control signal is at least one of Channel Quality Control Information, Channel Quality Indicator, Precoding Matrix Indicator, Rand Indicator, HARQ-ACK information, and Scheduling Request. Bureau. A mobile communication method for communicating between a radio base station and a mobile station,
Step A in which the radio base station notifies a parameter for an uplink control signal to the mobile station;
A step B in which the mobile station and the mobile station determine the number of symbols for the control signal of the uplink signal based on the parameter; and
The mobile station has a step C of transmitting the uplink control signal with the determined number of symbols to the radio base station;
In the step B, the number of symbols is determined based on a modulation scheme.

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