JP5641880B2 - Base station apparatus and control method for base station apparatus - Google Patents

Description

  The present invention relates to a base station apparatus and a control method for the base station apparatus.

  In recent years, communication technologies such as LTE (long term evolution) and IMT-Advanced have been developed. First, in the uplink by SC-FDMA (single carrier frequency division multiple access) in the LTE system, a fractional transmission power control (fractional) is a control method for controlling a transmission power target value for each terminal communicating with a base station apparatus. transmission power control (FTPC) is adopted. In the fractional transmission power control, the transmission power target value of a terminal close to the base station apparatus is set high to increase the throughput. On the other hand, the transmission power target value of the terminal near the cell edge is set low, the interference with other cells is reduced, and the overall throughput is improved.

  In IMT-Advanced, adoption of antenna technology of MIMO (multi input multi output) is being studied. By using MIMO, the cell average frequency utilization efficiency of the terminal at the cell edge can be improved. In particular, in base station cooperative MIMO (CoMP), since one terminal performs MIMO communication with a plurality of base station apparatuses, a low output base station apparatus with a small cell radius and a relatively high output with a large cell radius. The power received by the low-power base station apparatus having a small cell radius from the terminal performing MIMO communication with both of the base station apparatuses is larger than the power received by the base station apparatus having a large cell radius.

  Thus, when a base station apparatus communicates with a terminal, the input level of a signal arriving at the base station apparatus from the terminal may be very high. In such a case, if the linearity performance with respect to the high input level signal of the receiving unit provided in the base station apparatus is low, the signal is deteriorated and, consequently, the communication quality is deteriorated.

  Therefore, conventionally, as a technique for improving the linearity performance of the receiving unit, there is a method of adjusting the input level of the A / D converter using a reference signal (see, for example, Patent Document 1). As another technique for improving the linearity performance of the receiving unit, there is a method using an AGC (Automatic Gain Control) amplifier (for example, see Patent Document 2). The AGC amplifier is provided in a base station apparatus or the like of a wireless mobile communication system and converges a received signal to a predetermined dynamic range. The received signal is amplified by the AGC amplifier, and the output is given to the AGC amplifier control unit. The AGC amplifier control unit controls the gain of the AGC amplifier so that the output amplitude of the AGC amplifier is constant regardless of the amplitude of the input signal.

Japanese National Patent Publication No. 10-506762 JP 2009-246434 A

  However, in Patent Document 1, a level detection device and a gain control device are required, resulting in increased component costs. In addition, as a method for accurately reproducing the signal on the receiver side, it is conceivable to improve the linearity of the radio circuit of the receiver. For this purpose, however, expensive parts with high power consumption must be used. In other words, the cost of the circuit increases.

  Also, as in Patent Document 2, when an AGC amplifier is used, in OFDM communication such as LTE, the output amplitude is constant within a period of GI (Guard Interval) for avoiding delay spread interference and CP (Cyclic Prefix). It is necessary to converge so that For example, in LTE, CP is 32.6 nanoseconds × 144 samples = 4.6 μsec. Therefore, in order to stabilize the output amplitude within that period, the circuit scale of the AGC amplifier must be very large. I must. Furthermore, in OFDM communication, since the dynamic range of terminals that communicate at the same time is wide, if the output of the AGC amplifier of the base station apparatus is converged according to one of the communicating terminals, the base station apparatus and There is a possibility that the communication environment with other terminals in communication may deteriorate.

  Further, the deterioration of communication quality in a base station apparatus that performs communication corresponding to SC-FDMA in LTE system and MIMO (CoMP) in IMT-Advanced is remarkable in the case of the multi-level modulation method. That is, when communication is performed that employs a modulation scheme including amplitude modulation such as 16QAM (quadrature amplitude modulation) and 64QAM, rather than phase modulation such as QPSK (quadrature phase shift keying), communication quality is deteriorated. The degree is large. Therefore, it is assumed that the linearity performance of the receiving unit is improved by adjusting the gain of the receiving unit of the base station apparatus to be low. This is because, as shown in FIG. 10, when the gain is low (gain G2, curve 2), the linear operation range of the receiving unit is wider than when the gain is high (gain G1, curve 2). .

  Furthermore, the relationship between the input level and EVM (Error Vector Magnitude) at the receiver follows a curve as shown in FIG. That is, up to a predetermined input level (first threshold value T1), the EVM decreases (low level region) due to the noise figure (NF) of the receiving unit. Up to the input level of the second threshold value T2, which is larger than the first threshold value T1, the EVM is constant even if the input level increases (linear region). Even in this range, the gain ripple of the filter, the group delay deviation Affected by the phase noise of the local signal. When the input level is equal to or higher than the second threshold T2, EVM increases as the input level increases, and is affected by nonlinear distortion caused by an amplifier or a mixer (nonlinear region). Generally, a required EVM value is determined for each modulation method such as QPSK, 16QAM, and 64QAM. The larger the modulation multi-level number, the smaller the required EVM value. Therefore, if the input level of a signal having a large modulation multi-level number (multi-level modulation signal) increases, demodulation becomes impossible.

  If the gain of the receiving unit is set low, the communication quality of the multilevel modulation signal received at a relatively high level can be improved. However, in this case, the reception performance of a signal received at a low level is deteriorated. Such control cannot provide the same communication quality for a low level signal from a terminal far from the base station apparatus and a high level signal from a terminal close to the base station apparatus.

  Accordingly, an object of the present invention made in view of such points is to provide a base station apparatus and a control method for the base station apparatus that can provide a wide dynamic range and improve communication quality with a low-cost and simple configuration. It is to be.

Invention of group Chikyoku device you achieve the above object,
A base station apparatus comprising a plurality of receiving units each having an AGC amplifier for amplifying a received signal, and performing radio communication simultaneously with a plurality of terminals,
A control unit for controlling a gain of an AGC amplifier of at least one of the reception units based on reception states of signals from the plurality of terminals in the plurality of reception units ;
When the terminal that is performing MIMO communication stops the MIMO communication and raises the modulation scheme of any terminal to a modulation class with a large modulation multi-value number, the control unit is higher than the total throughput of all the current terminals When the total throughput of all the terminals is large, control is performed so that the gain of the AGC amplifier of the receiving unit communicating with the terminal when the modulation scheme is raised is lowered .

Further, the invention of the control method of the group Chikyoku device you achieve the above object,
A control method for a base station apparatus comprising a plurality of receiving units each having an AGC amplifier for amplifying a received signal, and performing radio communication simultaneously with a plurality of terminals,
The total of all terminals when a terminal executing MIMO communication stops the MIMO communication and raises the modulation scheme of any terminal to a modulation class having a large modulation multi-value number, compared to the current total throughput of all terminals when throughput is large, it is to have a step of decreasing the gain of the AGC amplifier of the receiver unit to communicate with terminals at the time of raising the modulation scheme.

  Advantageous Effects of Invention According to the present invention, it is possible to provide a base station apparatus and a control method for the base station apparatus that can easily provide a wide dynamic range and improve communication quality at low cost.

It is a block diagram which shows schematic structure of the base station apparatus which concerns on 1st Embodiment of this invention. 3 is a flowchart showing an operation of the base station apparatus shown in FIG. It is a figure which shows an example of the communication state of the base station apparatus of FIG. FIG. 3 is a diagram showing the relationship between the input level of the receiving unit and the EVM at the time of step S01 in FIG. FIG. 3 is a diagram showing the relationship between the input level of the receiving unit and the EVM at the time after the gain reduction in step S04 of FIG. It is a figure which shows the relationship between the input level of a receiving part and EVM at the time of step S07 of FIG. It is a figure which shows the relationship between the input level of a receiving part and EVM at the time of step S10 of FIG. It is a figure which shows the relationship between the input level of a receiving part and EVM at the time of step S12 of FIG. It is a figure for demonstrating the process in FIG.2 S11. It is a figure which shows the relationship between the input level and output level in a general receiving part. It is a figure which shows the relationship between the input level and EVM in a general receiving part.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a base station apparatus according to an embodiment of the present invention. As illustrated in FIG. 1, the base station device 1A is configured as, for example, a microcell base station, and includes a first receiver 1, a second receiver 2, a first transmitter 3, and a second A transmission unit 4 and a control unit 5 are provided.

  1 A of base station apparatuses are comprised from the 1st receiving part 1, the 2nd receiving part 2, the 1st transmission part 3, the 2nd transmission part 4, and the control part 5. FIG. The first receiver 1 includes an antenna 1a, an LNA (Low Noise Amplifier) 1b, a mixer 1c, a local signal oscillator 1d, an AGC (Automatic Gain Control) amplifier 1e, an A / D converter 1f, and an OFDMA (Orthogonal Frequency Division Multiple Access). It has a demodulation processing unit 1g.

  The second receiving unit 2 includes an antenna 2a, an LNA 2b, a mixer 2c, a local signal oscillator 2d, an AGC amplifier 2e, an A / D converter 2f, and a DMA demodulation processing unit 2g. The first transmission unit 3 includes an antenna 3a and a transmission circuit unit 3b. The second transmission unit 4 includes an antenna 4a and a transmission circuit unit 4b. The functional component of the second receiver 2 has the same function as the functional component of the first receiver 1, and the functional component of the second transmitter 4 is the functional component of the first transmitter 3. The description is omitted because it has the same function.

  The antenna 1a outputs the reception signal received from the terminal B to the LNA 1b. The LNA 1b is an amplifier having a low noise figure, amplifies the received signal input from the antenna 1a, and outputs the amplified signal to the mixer 1c. The mixer 1c mixes the received signal input from the LNA 1b and the local signal input from the local signal oscillator 1d, thereby frequency-converting (down-converting) the received signal to an IF frequency, and an AGC amplifier as the IF received signal 1e is output.

  The local signal oscillator 1d generates a local signal for IF frequency conversion and outputs it to the mixer 1c. The AGC amplifier 1e is a variable gain amplifier whose gain is controlled based on the control of the control unit 5. The AGC amplifier 1e amplifies the IF reception signal input from the mixer 1c and outputs it to the A / D converter 1f.

  The A / D converter 1f constitutes a signal processing unit together with the OFDMA demodulation processing unit 1g. Specifically, the A / D converter 1f digitally converts the IF reception signal input from the AGC amplifier 1e and outputs the digital IF reception signal to the OFDMA demodulation processing unit 1g. The OFDMA demodulation processing unit 1g subjects the digital IF reception signal input from the A / D converter 1f to demodulation processing of a signal based on the OFDMA method such as Fourier transform, digital demodulation, and parallel-serial conversion, and controls it as a baseband received signal Output to unit 5. Further, the OFDMA demodulation processing unit 1 g detects an RSSI (Received Signal Strength Indicator) of the IF reception signal input to the A / D converter 1 f and outputs the detection result to the control unit 5.

  The antenna 3a transmits the transmission signal input from the transmission circuit unit 3b to the outside. The transmission circuit unit 3b outputs a transmission signal to the antenna 1a under the control of the control unit 5. The control unit 5 includes an internal memory including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), the first receiving unit 1, the second receiving unit 2, and the first transmitting unit. 3 and an interface circuit for inputting / outputting signals to / from the second transmission unit 4. The control program stored in the ROM and the first reception unit 1 and the second reception unit 2 receive the control program. The overall operation of the microcell base station A1 is controlled based on the signal. The control program stored in the ROM includes an AGC amplifier control program, and the control unit 5 controls the gains of the AGC amplifiers 1e and 2e based on the AGC amplifier control program.

  FIG. 2 is a flowchart showing an operation of the base station apparatus shown in FIG. Here, as shown in FIG. 3, it is assumed that base station apparatus 1 </ b> A communicates with a plurality of terminals. FIG. 3 is a diagram illustrating an example of a communication state of the base station apparatus of FIG. The base station apparatus 1A performs switching between MIMO communication and communications other than MIMO as appropriate according to the communication environment. Here, the base station apparatus 1A performs 2 × 2 MIMO communication or communication other than MIMO (for example, 1 × 2 SIMO (Single Input Multi Output) communication) with the terminal 11, and performs SISO (Single Input Single Output) communication shall be executed.

  As the reception state, the control unit 5 detects that the reception level of a signal from a certain terminal is high (a), or that the communication quality of a certain terminal has deteriorated (b) (S01). Specifically, the control unit 5 detects that the reception level of the signal from the communicating terminal is equal to or higher than a predetermined threshold value. Further, the control unit 5 detects that the signal-to-noise ratio (SNR) is equal to or less than a predetermined threshold value, or an increase in CRC (Cyclic redundancy check) error, and the communication quality is deteriorated based on the detection result. To detect. The control unit 5 stores the input level from the terminal corresponding to (a) or (b) detected in step S01 as Pin_a in a storage unit (not shown).

  When detecting the above-described (a) or (b) in step S1, the control unit 5 detects the communication state of all the terminals communicating with the base station device 1A (S02). Specifically, the control unit 5 grasps, for example, the presence / absence of MIMO communication, the modulation scheme, the communication signal level, etc. as the communication state for all terminals communicating with the base station apparatus 1A.

  The control unit 5 determines whether there is a terminal that is performing MIMO communication with the base station apparatus 1A based on the communication state grasped in step S02 (S03). When the base station apparatus 1A is not performing MIMO communication with the terminal 11 of FIG. 3, the control unit 5 determines “No” in step S03, and for example, the AGC amplifier 2e of the second receiving unit 2 is used. Is reduced (No in S03, S04). At this time, for example, the control unit 5 reduces the gain of the AGC amplifier 2e step by step so that the gain at the input level Pin_a stored in the storage unit (not shown) in step S01 decreases, and the communication quality improves at each step. It is determined whether or not (S05). When it is determined as “Yes” in step S05, the control unit 5 controls the gain adjustment operation so as to maintain the gain of the AGC amplifier 2e at that stage.

  When determining “No” in step S05, the control unit 5 determines whether or not the gain of the AGC amplifier 2e at that stage is larger than the limit value (S06). The limit value is, for example, a predetermined minimum gain of the AGC amplifier 2e. When determining “Yes” in step S06, the control unit 5 further reduces the gain of the AGC amplifier 2e (Yes in S06, S04). When determining “No” in step S06, the control unit 5 sets the gain of the AGC amplifier 2e to a limit value.

On the other hand, when the terminal 11 and the base station apparatus 1A shown in FIG. 3 are performing MIMO communication, the control unit 5 determines “Yes” in step S03 and uses the minimum value Pin_m of the input level of the terminal as a reference. Then, the minimum adjustment gain Gmin_m is determined (S07). Here, the minimum adjustment gain Gmin_m is a value used as the minimum value of the gain when adjusting the gain of the AGC amplifier 2e. Since the minimum adjustment gain Gmin_m is determined so that a multi-level modulation method (for example, QPSK ) can be received with reference to the minimum value Pin_m of the input level from the terminal during the MIMO communication, the multilevel value is used even at the minimum input level Pin_m. MIMO communication based on the modulation scheme can be maintained.

  Then, for example, the control unit 5 reduces the gain of the AGC amplifier 2e of the second reception unit 2 to the minimum adjustment gain Gmin_m determined in step S07 (S08). Next, the control unit 5 determines whether or not the communication quality is improved (S09). If it is determined “No” in step S09, scheduling is performed (S10). Specifically, the control unit 5 stops the current throughput value TP (A) and the throughput value TP (B when the modulation class (that is, the modulation multi-level number) is improved by stopping the MIMO communication. ) And calculate whether the value of TP (B) exceeds the value of TP (A) (S11).

  If the control unit 5 determines “Yes” in step S11, that is, if the MIMO communication is stopped and the modulation class (that is, the modulation multi-level number) is increased, the throughput is larger than the current state. If it is determined, the gain of the AGC amplifier 2e is further reduced, and it is determined whether or not the communication quality and throughput are improved (S12). When determining “No” in step S12, the control unit 5 controls the gain adjustment operation so as to be in the communication state after the scheduling in step S10 (S13).

  On the other hand, when it determines with Yes at step S09, the control part 5 maintains the communication state, and complete | finishes a process (Yes of S09, S14). In addition, when the control unit 5 determines “No” in step S11, that is, when the current throughput of performing MIMO communication stops the MIMO communication and increases the modulation class (that is, the modulation multi-level number). If it is determined that the throughput is equal to or greater than the throughput, the communication state is maintained and the gain adjustment operation is terminated (No in S11, S15). Further, when it is determined as “Yes” in step S12, that is, when the communication quality and the throughput are improved when the gain is reduced, the gain adjustment operation is performed so as to maintain the communication state with the reduced gain. (Yes in S12, S15).

  Next, the relationship between the input levels of the first receiving unit 1 and the second receiving unit 2 and the EVM at the time of each step described above will be described. FIG. 4 is a diagram showing the relationship between the input levels and EVMs of the first receiving unit 1 and the second receiving unit 2 of the base station apparatus 1A at the time of step S01 in FIG. At this time, the gains of the AGC amplifiers 1e and 2e are the same, and MIMO communication using QPSK is possible within the range indicated by the broken line. In step S01, at the input level Pin_a of the terminal that satisfies the condition (a) or (b) detected by the control unit 5, QPSK communication is possible due to EVM restrictions, but 16QAM and 64QAM communication is not possible. Is possible.

  FIG. 5 is a diagram showing the relationship between the input levels and EVMs of the first receiving unit 1 and the second receiving unit 2 of the base station apparatus 1A at the time after the gain reduction in step S04 of FIG. Here, the control unit 5 shifts the communication range of the second reception unit 2 to the right in the drawing by reducing the gain of the AGC amplifier 2e of the second reception unit 2, and the first reception unit 1 or the second reception unit. The range of input levels that can be received by any one of the units 2 is expanded. Thereby, even in the case of the input voltage Pin_a, it is possible to receive up to QPSK, 16QAM, and 64QAM.

  FIG. 6 is a diagram showing the relationship between the input levels and EVMs of the first receiving unit 1 and the second receiving unit 2 of the base station apparatus 1A at the time of step S07 in FIG. In this case, the base station apparatus 1A performs MIMO communication with the terminal 11. Then, the input level of the terminal 11 performing the MIMO communication is Pin_m, and the input level of the terminal satisfying the condition (a) or (b) detected by the control unit 5 in step S01 of FIG. 2 is Pin_a. It is. In the reception range of the first receiver 1 and the second receiver 2 as shown in FIG. 6, only QPSK communication can be performed when the input level is Pin_a.

  FIG. 7 is a diagram showing the relationship between the input levels and EVMs of the first receiving unit 1 and the second receiving unit 2 of the base station apparatus 1A at the time of step S10 in FIG. Here, the control unit 5 shifts the reception range of the second reception unit 2 by reducing the gain of the AGC amplifier 2e of the second reception unit 2, and the first reception unit 1 or the second reception unit 2 The range of input levels that can be received by either is expanded. In reducing the gain of the AGC amplifier 2e of the second receiving unit 2, the gain of the AGC amplifier 2e is reduced so that at least QPSK can be received by both the first receiving unit 1 and the second receiving unit 2. That is, the gain of the AGC amplifier 2e is reduced based on the above-described minimum adjustment gain Gmin_m.

  As a result, QPSK and 16QAM can be received regardless of whether the input level is Pin_a or Pin_m. The terminal 11 that is performing MIMO communication with the base station apparatus 1A and whose input level is Pin_m can maintain the MIMO communication in QPSK. In this way, the MIMO communication of the terminal 11 is maintained by shifting the communication range of the second receiver 2 with the upper limit of the range in which the second receiver 2 can receive QPSK when the input level is Pin_m. Can do.

  FIG. 8 is a diagram showing the relationship between the input levels and EVMs of the first receiving unit 1 and the second receiving unit 2 of the base station apparatus 1A at the time of step S12 in FIG. Here, the control unit 5 shifts the reception range of the second reception unit 2 by further reducing the gain of the AGC amplifier 2e of the second reception unit 2, and the first reception unit 1 or the second reception unit 2 The range of input levels that can be received by either of the above is expanded. As a result, 64QAM can be received not only when the input level is Pin_m but also when Pin_a. On the other hand, the terminal 11 performing MIMO communication with the base station apparatus 1A and having an input level of Pin_m receives the second reception in the reception ranges of the first receiver 1 and the second receiver 2 shown in FIG. Since it is out of the reception range of the unit 2, it is no longer possible to maintain the MIMO communication. For this reason, the control unit 5 shifts the communication with the terminal 11 from the MIMO communication to the SIMO communication.

  FIG. 9 is a diagram for explaining the processing in step S11 of FIG. FIG. 9A shows an example of the current throughput value TP (A) for a terminal (user) communicating with the base station apparatus 1A before scheduling in step S10 of FIG. FIG. 9B shows an example of a throughput value TP (B) for a terminal (user terminal) that communicates with the base station apparatus 1A when scheduling is performed in step S10 of FIG. Actually, the base station apparatus 1A can accommodate thousands of user terminals. Here, as an example, it is assumed that four user terminals UE1 to UE4 are communicating with the base station apparatus 1A. .

  As shown in FIG. 9A, the user terminal UE1 is performing 2 × 2 MIMO communication with the base station apparatus 1A, and the MIMO coefficient indicating the rate of improvement in communication efficiency by MIMO is 0.6. Yes, the throughput is 460800 bps. Similarly, the user terminal UE4 is performing QPSK communication and performing SISO communication. On the other hand, as shown in FIG. 9B, when the MIMO communication is stopped and the user terminal UE1 is changed to the SISO communication, the throughput for the UE1 is lower than that shown in FIG. When the modulation class (that is, the modulation multi-level number) of UE4 is improved to 64QAM, the throughput for UE4 is dramatically improved, and the total throughput value is improved as compared with the case shown in FIG. 9A. . In such a case, the control unit 5 determines “Yes” in step S11 of FIG. 2, and confirms improvement in communication quality and throughput in step S12 of FIG. The communication state as shown in FIG. That is, the MIMO communication of the user terminal UE1 is stopped and the communication with the user terminal UE4 is controlled to be 64QAM communication.

  Thus, the base station apparatus 1A according to the present embodiment controls the gain of at least one AGC amplifier 1e or 2e of the first receiver 1 or the second receiver 2 according to the level of the received signal. 5, a wide dynamic range can be provided and communication quality can be improved with a low-cost and simple configuration.

  Specifically, the control unit 5 lowers the gain of at least one AGC amplifier 1e or 2e of the first receiving unit 1 or the second receiving unit 2 when the base station apparatus 1A is not performing MIMO communication. By controlling in this way, the high input level signal is also included in the linear operation range, so that the communication quality for the high input level signal can be improved and the communication quality for the low input level signal can be maintained. be able to.

  In addition, when the base station apparatus 1A is performing MIMO communication, the control unit 5 receives the gain of at least one AGC amplifier 1e or 2e of the first receiving unit 1 or the second receiving unit 2 through MIMO communication. Therefore, it is possible to maintain the MIMO communication with the terminal in the MIMO communication, and to control the input level of the communicable input level. The range can be expanded.

  In addition, this invention is not limited only to embodiment mentioned above, Many change or deformation | transformation is possible. For example, in the above embodiment, the base station apparatus 1A includes two receiving units, but the base station apparatus 1A includes two or more receiving units and controls the gain of the AGC amplifier included in at least one receiving unit. It may be configured to. As a result, the dynamic range can be expanded.

DESCRIPTION OF SYMBOLS 1 1st receiving part 1a, 2a Antenna 1b, 2b LNA (Low Noise Amplifier)
1c, 2c Mixer 1d, 2d Local signal oscillator 1e, 2e AGC (Automatic Gain Control) amplifier 1f, 2f A / D converter 1g, 2g OFDMA (Orthogonal Frequency Division Multiple Access) demodulation processor 2 Second receiver 3 First transmission Unit 4 second transmission unit 3a, 4a antenna 3b, 4b transmission circuit unit 5 control unit 1A base station apparatus

Claims (2)

A base station apparatus comprising a plurality of receiving units each having an AGC amplifier for amplifying a received signal, and performing radio communication simultaneously with a plurality of terminals,
A control unit for controlling a gain of an AGC amplifier of at least one of the reception units based on reception states of signals from the plurality of terminals in the plurality of reception units ;
When the terminal that is performing MIMO communication stops the MIMO communication and raises the modulation scheme of any terminal to a modulation class with a large modulation multi-value number, the control unit is higher than the total throughput of all the current terminals When the total throughput of all the terminals is large, the base station apparatus performs control so as to decrease the gain of the AGC amplifier of the receiving unit that communicates with the terminal when the modulation scheme is increased . A control method for a base station apparatus comprising a plurality of receiving units each having an AGC amplifier for amplifying a received signal, and performing radio communication simultaneously with a plurality of terminals,
The total of all terminals when a terminal executing MIMO communication stops the MIMO communication and raises the modulation scheme of any terminal to a modulation class having a large modulation multi-value number, compared to the current total throughput of all terminals when throughput is large, the control method of a base station apparatus that have a step of decreasing the gain of the AGC amplifier of the receiver unit to communicate with terminals at the time of raising the modulation scheme.

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