JP4930348B2 - Wireless communication apparatus, wireless communication system, and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication system, and a wireless communication method.

  In a wireless communication system, since reception power varies depending on radio wave propagation path conditions, an automatic gain control device for adjusting reception power in a communication device on the reception side is generally used. In particular, in a mobile communication system, since communication characteristics vary according to the positional relationship between a mobile station and a base station, adjustment of received power by automatic gain control is important.

  The automatic gain control device includes, for example, a variable gain amplification unit and a control voltage generation unit. In the automatic gain control device, the received signal is amplified to a predetermined level by the variable gain amplifier and output to the receiving circuit. Also, a control voltage for gain control of the received signal to a predetermined level based on the amplified received signal is generated by the control voltage generating unit and supplied to the variable gain amplifying unit. Here, the control voltage generator generates a control voltage by comparing the received power of the gain-controlled signal with a predetermined level at regular intervals.

JP-A-9-64672 JP-A-9-135136 Japanese Patent Laid-Open No. 10-32443

  In broadband data transmission, multi-channel transmission is used in which data transmission is performed in parallel by a plurality of subchannels assigned different frequencies. In multi-channel transmission, a communication device on the receiving side in a conventional wireless communication system receives and demodulates a transmission signal in which signals corresponding to each sub-channel are frequency-multiplexed, and includes frequency signals including all sub-channel signals. Gain control is performed based on the received power of the waved signal. On the other hand, in a plurality of subchannels to which different frequencies are assigned, radio wave propagation path conditions differ for each subchannel according to the assigned frequencies. For this reason, even if gain control is appropriately performed on a signal of a specific subchannel, it may not be appropriately performed on signals of other subchannels. As a result, there is a problem that data transmission characteristics deteriorate in multi-channel transmission.

  The present invention has been made in view of the above problems, and a purpose thereof is a new and improved wireless communication apparatus capable of appropriately performing gain control on a received signal even when performing multi-channel transmission. , A wireless communication system, and a wireless communication method.

  In order to solve the above problems, according to a first aspect of the present invention, there is provided a wireless communication apparatus that performs data transmission in parallel by a plurality of subchannels assigned different frequencies. The wireless communication apparatus includes an antenna unit that receives a signal transmitted by frequency-combining signals of each subchannel, a demodulator that demodulates the received signal, and converts the demodulated signal into a signal of each subchannel. A frequency demultiplexing unit that demultiplexes the frequency, and an automatic gain control unit that is provided corresponding to each subchannel and performs automatic gain control on the signal of each corresponding subchannel that is frequency demultiplexed. Features.

  According to such a configuration, a transmission signal obtained by frequency-combining each subchannel signal is received and demodulated, frequency-demultiplexed into each subchannel signal, and then gain control is performed on each subchannel signal. Is done. As a result, even when the propagation path condition of the radio wave is different for each subchannel, gain control is performed on the signal of each subchannel, so that gain control can be appropriately performed on the received signal.

  The wireless communication apparatus may be applied to a mobile communication system that performs wireless communication between a mobile station and a base station for which a movement route is determined. According to this configuration, even when the communication characteristics vary according to the positional relationship between the mobile station and the base station, it is possible to appropriately perform gain control on the received signal.

  The automatic gain control unit stores a variable gain amplifying unit that amplifies each subchannel signal to a predetermined level, and a variation pattern that represents the received power of each subchannel signal measured in advance along the movement path. A power fluctuation storage unit that compares the amplified signal of each subchannel with the fluctuation pattern and predicts the received power of the signal of each subchannel at the next time, and each predicted subchannel A control voltage generation unit that generates a control voltage for amplifying the signal of each subchannel to a predetermined level based on the reception power of the signal of the channel and supplies the control voltage to the variable gain amplification unit. According to this configuration, the reception power of the signal of each subchannel is predicted, and a control voltage for amplifying the signal of each subchannel to a predetermined level is generated based on the predicted reception power. As a result, the gain of the variable amplifier can be determined at an early stage, so that the gain control can be accurately performed on the signal of each subchannel.

  Also, a demodulator for demodulating the signal of each corresponding subchannel, which is provided corresponding to each subchannel and subjected to automatic gain control, at a frequency assigned to each subchannel, and provided corresponding to each subchannel. A baseband demodulator for baseband demodulating the signal of each corresponding subchannel demodulated at the frequency assigned to each subchannel, and a parallel series for converting the baseband demodulated signal of each subchannel to a baseband signal And a conversion unit. According to such a configuration, a reception signal whose gain is appropriately controlled is converted into a baseband signal, so that deterioration of data transmission characteristics in multi-channel transmission can be eliminated.

  In order to solve the above-described problem, according to a second aspect of the present invention, a plurality of subchannels assigned different frequencies from a wireless communication device on the transmission side to a wireless communication device on the reception side are provided. A wireless communication system that performs data transmission in parallel is provided. In this radio communication system, a radio communication device on the receiving side includes an antenna unit that receives a signal transmitted from a radio communication device on the transmission side by frequency-combining the signals of each sub-channel, and a received signal. A demodulator that demodulates, a frequency demultiplexer that demultiplexes the demodulated signal into signals of each subchannel, and a signal that is provided corresponding to each subchannel, And an automatic gain control unit that performs automatic gain control.

  According to such a configuration, a transmission signal obtained by frequency-combining the signals of each subchannel is received and demodulated from the radio communication apparatus serving as the transmission side by the radio communication apparatus serving as the reception side, and the frequency is added to the signal of each subchannel. After demultiplexing, gain control is performed on the signal of each subchannel. As a result, even when the propagation path condition of the radio wave is different for each subchannel, gain control is performed on the signal of each subchannel, so that gain control can be appropriately performed on the received signal.

  In order to solve the above-described problem, according to a third aspect of the present invention, a plurality of subchannels assigned different frequencies from a wireless communication device on the transmission side to a wireless communication device on the reception side. A wireless communication method applied to a wireless communication apparatus that performs data transmission in parallel is provided. In this radio communication method, a radio communication device on the receiving side receives a transmission signal obtained by frequency-combining the signals of each subchannel from the radio communication device on the transmission side, and demodulates and demodulates the received signal. The signal is frequency-demultiplexed into sub-channel signals, and automatic gain control is performed on each sub-channel signal that has been frequency-demultiplexed.

  According to this method, a transmission signal obtained by frequency-combining the signals of each subchannel is received from the wireless communication apparatus serving as the transmission side and demodulated by the wireless communication apparatus serving as the reception side, and the frequency is added to the signal of each subchannel. After demultiplexing, gain control is performed on the signal of each subchannel. As a result, even when the propagation path condition of the radio wave is different for each subchannel, gain control is performed on the signal of each subchannel, so that gain control can be appropriately performed on the received signal.

  According to the present invention, it is possible to provide a wireless communication apparatus, a wireless communication system, and a wireless communication method that can appropriately perform gain control on a received signal even when performing multi-channel transmission.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  In the following, first, problems in the conventional wireless communication device for multi-channel transmission will be described, and then the wireless communication device according to the embodiment of the present invention will be described.

  FIG. 5 is a functional configuration diagram showing a conventional multi-channel transmission wireless communication system to which an automatic gain control unit is applied.

As shown in FIG. 5, the conventional wireless communication system includes a transmitter 10 included in a communication device on the transmission side and a receiver 20 included in the communication device on the reception side. Note that FIG. 5 shows a wireless communication system that performs multi-channel transmission using subchannels assigned to _four different frequencies f _{1 to} f ₄ , but the number of subchannels is as follows. It is not limited.

  The transmitter 10 includes a serial / parallel conversion unit 11, baseband modulation units 12 a to 12 d, orthogonal modulation units 13 a to 13 d, a frequency multiplexing unit 14, a radio frequency (RF) modulation unit 15, and an antenna unit 16. Consists of including. Here, the baseband modulation units 12a to 12d and the orthogonal modulation units 13a to 13d are provided in parallel so as to correspond to the subchannels in the number corresponding to the subchannels.

The serial / parallel converter 11 converts the baseband signal supplied from the upper layer into a data string corresponding to each subchannel, and outputs the data string to the baseband modulators 12a to 12d. The baseband modulation units 12a to 12d modulate a carrier based on the data sequence corresponding to each subchannel, and output the result to the orthogonal modulation units 13a to 13d. The quadrature modulation units 13 a to 13 d perform quadrature modulation on the modulated signals corresponding to the respective subchannels at the frequencies f _{1 to} f ₄ assigned to the respective subchannels, and output the resulting signals to the frequency multiplexing unit 14. The frequency multiplexing unit 14 frequency-multiplexes the orthogonally modulated signals corresponding to the respective subchannels and outputs the resultant signals to the RF modulation unit 15. The RF modulation unit 15 modulates the frequency-multiplexed signal and transmits the modulated signal to the reception-side communication device via the antenna unit 16.

  The receiver 20 includes an antenna unit 21, a radio frequency (RF) demodulation unit 22, an automatic gain control unit (AGC) 24, a frequency demultiplexing unit 23, orthogonal demodulation units 25a to 25d, and a baseband demodulation unit 26a to 26d. 26d and a parallel / serial converter 27. Here, the orthogonal demodulating units 25a to 25d and the baseband demodulating units 26a to 26d are provided in parallel so as to correspond to the respective subchannels in a number corresponding to the subchannels.

The RF demodulator 22 demodulates the transmission signal that is input from the antenna unit 21 and frequency-multiplexed with the signal corresponding to each subchannel, and outputs the demodulated signal to the AGC unit 24. The AGC unit 24 performs gain control on the received signal and outputs it to the frequency demultiplexing unit 23. The frequency demultiplexing unit 23 demultiplexes the gain-controlled signal into signals of frequencies f _{1 to} f ₄ assigned to the respective subchannels, and outputs the demultiplexed signals to the orthogonal demodulation units 25 a to 25 d corresponding to the respective subchannels. The quadrature demodulation units 25a to 25d perform quadrature demodulation on the demultiplexed signals corresponding to the respective subchannels, and output them to the baseband demodulation units 26a to 26d. The baseband demodulation units 26 a to 26 d demodulate the signal corresponding to each subchannel into a data string, and output the data string to the parallel / serial conversion unit 27. The parallel / serial converter 27 converts the demodulated data sequence corresponding to each subchannel into a baseband signal and supplies it to the upper layer.

The receiver 20 receives multi-channel signals transmitted in parallel by a plurality of subchannels assigned different frequencies f _{1 to} f ₄ . Here, the received power is affected by radio wave interference, fading, and the like generated on the propagation path from the transmitter 10 to the receiver 20, and thus fluctuates according to the state of the radio wave propagation path. In addition, the degree of influence of radio wave interference, fading, and the like changes according to the frequency of the radio wave and, when the communication apparatus is a mobile station, also according to the moving speed of the mobile station. For this reason, a situation occurs in which received power is different for each subchannel to which different frequencies f _{1 to} f ₄ are assigned.

  FIG. 6 is an explanatory diagram showing the result of gain control by a conventional wireless communication apparatus in order to explain this situation. In FIG. 6, the horizontal axis represents frequency (f), the vertical axis represents transmission / reception power (P) and the frequency response (r) of the propagation path, and bar graph 2 shows transmission / reception power and a line graph. 5 shows the frequency response.

FIG. 6A shows the transmission power of the transmitted multi-channel signal and the frequency response of the propagation path as preconditions used in the following description. As shown in FIG. 6 (a), the transmitter 10 transmits a signal with the same transmission power P ₀ by each sub-channel assigned different frequencies f ₁ ~f ₄ together. On the other hand, the frequency response of the propagation path differs for each signal of the frequencies f _{1 to} f ₄ assigned to each sub-channel because the influence of radio wave interference, fading and the like varies depending on the frequency.

FIG. 6B shows the received power at the receiver 20 that fluctuates depending on the propagation path condition when the receiver 20 does not perform gain control under the preconditions shown in FIG. 6A. Yes. As shown in FIG. 6 (b), the signals transmitted from the transmitter 10 with the same transmission power P ₀ by the subchannels to which the different frequencies f _{1 to} f ₄ are assigned are mutually transmitted according to the propagation path conditions. Received by the receiver 20 with different received power. That is, the signals of the subchannels to which the frequencies f ₁ and f ₂ having relatively high frequency responsiveness are assigned are received with relatively high reception power, and the frequencies f ₃ and f ₄ having relatively low frequency responsiveness are received. Are received with relatively low received power.

  FIG. 6C shows received power when gain control is performed by the receiver 20 under the preconditions shown in FIG. In this case, gain control is performed based on the received power of the frequency-multiplexed signal including all the subchannel signals. For this reason, as shown in FIG. 6C, it is affected by the signal of the subchannel received with a relatively high reception power, and the gain for the signal of the subchannel received with a relatively low reception power. Control is performed inappropriately (insufficiently). As a result, degradation of data transmission characteristics in multi-channel transmission occurs.

  Next, a wireless communication apparatus according to an embodiment of the present invention will be described. FIG. 1 is a functional configuration diagram illustrating a wireless communication system for multi-channel transmission according to an embodiment of the present invention.

  As shown in FIG. 1, the wireless communication system according to the present embodiment includes a transmission-side communication device and a reception-side communication device, similarly to the conventional wireless communication system. The transmission-side communication apparatus includes a transmitter 110 having the same functional configuration as that of a conventional wireless communication system. On the other hand, the transmission device on the reception side includes a receiver 120 having a functional configuration different from that of the conventional wireless communication system.

  Hereinafter, a functional configuration of the receiver 120 that is characteristic of the wireless communication apparatus according to the present embodiment will be described. The description of the functional configuration common to the conventional receiver 20 among the functional configuration of the transmitter 110 and the functional configuration of the receiver 120 is omitted.

  The receiver 120 includes an antenna unit 121, a radio frequency (RF) demodulation unit 122, a frequency demultiplexing unit 123, automatic gain control (AGC) units 124a to 124d, quadrature demodulation units 125a to 125d, baseband demodulation units 126a to 126d, And a parallel / serial converter 127. Here, the AGC units 124a to 124d, the orthogonal demodulation units 125a to 125d, and the baseband demodulation units 126a to 126d are provided in parallel so as to correspond to the subchannels in the number corresponding to the subchannels.

The RF demodulator 122 demodulates a transmission signal that is input from the antenna unit 121 and frequency-multiplexed with the signal corresponding to each subchannel, and outputs the demodulated signal to the frequency demultiplexing unit 123. The frequency demultiplexing unit 123 demultiplexes the received signal into signals of frequencies f _{1 to} f ₄ assigned to the respective subchannels, and outputs the demultiplexed signals to the AGC units 124 a to 124 d corresponding to the respective subchannels. AGC sections 124a to 124d perform gain control on the frequency-demultiplexed signals corresponding to the respective subchannels, and output the signals to orthogonal demodulation sections 125a to 125d corresponding to the respective subchannels. Orthogonal demodulation units 125a to 125d perform orthogonal demodulation on the gain-controlled signals corresponding to the respective subchannels, and output the signals to baseband demodulation units 126a to 126d corresponding to the respective subchannels. Baseband demodulation sections 126a to 126d demodulate the signals corresponding to the respective subchannels into data strings, and output the data strings to parallel / serial conversion section 127. The parallel / serial converter 127 converts the demodulated data sequence corresponding to each subchannel into a baseband signal and supplies the baseband signal to the upper layer.

  FIG. 2 is an explanatory diagram illustrating a result of gain control by the wireless communication apparatus according to the present embodiment. FIG. 2 (a) shows the preconditions used in the following description, and FIG. 2 (b) shows the propagation when the receiver 120 does not perform gain control under the preconditions shown in FIG. 2 (a). The reception power at the receiver 120 that varies depending on the road condition is shown. 2 (a) and 2 (b) are the same as FIGS. 6 (a) and 6 (b) described above, and detailed description thereof is omitted.

  FIG. 2C shows received power when gain control is performed by the receiver 120 under the preconditions shown in FIG. In this case, unlike the case shown in FIG. 6C, gain control is performed based on the received power of the signal of each subchannel, that is, each frequency-demultiplexed subchannel. Therefore, as shown in FIG. 2C, the subchannel signal received with a relatively low reception power is not affected by the signal of the subchannel received with a relatively high reception power. Gain control is performed appropriately. As a result, it is possible to eliminate degradation of data transmission characteristics in multi-channel transmission.

  FIG. 3 is a functional configuration diagram illustrating the first embodiment of the AGC unit provided in the receiver. As shown in FIG. 3, the AGC unit 130 (corresponding to the AGC unit 124 of FIG. 1) provided in the receiver 120 includes a variable gain amplifying unit 132 and a control voltage generating unit 134.

  In the AGC unit 130, the signal of each subchannel is amplified to a predetermined level by the variable gain amplification unit 132, and is output to the receiving circuit as an AGC output signal. Further, a control voltage for gain control of each subchannel signal to a predetermined level based on the amplified signal of each subchannel is generated by the control voltage generation unit 134 and supplied to the variable gain amplification unit 132. Here, the control voltage generator 134 generates a gain control voltage by comparing the received power of each gain-controlled signal of each subchannel with a predetermined level at regular intervals.

  As shown in FIG. 3, since the AGC unit 130 is configured to include a feedback circuit, it takes a certain time for the received signal to converge to a predetermined level. This means that communication characteristics deteriorate at a certain frequency when continuous communication is performed in a communication environment in which propagation path conditions fluctuate. Further, when the propagation path condition changes very quickly, the processing speed by the feedback circuit of the AGC unit 130 cannot follow the propagation path condition change, and gain control may not be performed properly. In particular, in multi-channel transmission, there is a problem that it is difficult to perform gain control appropriately because fluctuations in propagation path conditions vary depending on the frequency of each subchannel.

  For this reason, in a mobile communication system that performs communication between a mobile station and a base station, when a mobile path of the mobile station is determined, the propagation path condition of the radio wave between the mobile station and the base station is determined in advance. It is conceivable to appropriately perform gain control by measuring and predicting the propagation path condition of radio waves in real time based on the position of the mobile station.

  FIG. 4 is a functional configuration diagram illustrating a second embodiment of the AGC unit provided in the receiver in order to solve the above-described problem. As shown in FIG. 4, AGC section 140 (corresponding to AGC section 124 of FIG. 1) provided in receiver 120 includes variable gain amplification section 142, power fluctuation storage section 144, received power prediction section 146, and A control voltage generation unit 148 is included.

  The variable gain amplification unit 142 amplifies the signal of each subchannel to a predetermined level. The power fluctuation storage unit 144 stores a fluctuation pattern representing the received power of each subchannel signal measured in advance along the movement path as a prediction pattern. Here, the variation pattern stored as the prediction pattern may be a temporal variation in received power or a variation corresponding to a change in the position of the mobile station. The reception power prediction unit 146 compares the amplified signal of each subchannel with the prediction pattern, and predicts the reception power of the signal of each subchannel at the next time. The control voltage generator 148 generates a control voltage for amplifying each subchannel signal to a predetermined level based on the predicted received power of each subchannel signal, and supplies the control voltage to the variable gain amplifier 142.

  The received power prediction unit 146 compares a variation pattern representing the received power of each subchannel signal actually measured when the mobile station moves with a prediction pattern stored in advance through processing such as pattern matching. Here, in pattern matching, for example, position information of a mobile station obtained from a GPS device, a speed device, or the like may be referred to. Then, the received power prediction unit 146 specifies which part (temporal or positional) the received power of the signal of each subchannel actually measured at a certain time corresponds to in the prediction pattern. Then, the reception power of the signal of each subchannel at the next time is predicted based on the prediction pattern. The control voltage generation unit 148 compares the predicted received power of each subchannel signal with a predetermined level, and generates a control voltage for amplifying the signal of each subchannel at the next time to a predetermined level. And supplied to the variable gain control unit 142.

  Thereby, the reception power of the signal of each subchannel is predicted, and the gain of the variable gain amplifier 142 can be determined at an early stage, so that the gain control for the signal of each subchannel can be performed accurately.

  The wireless communication system according to the embodiment of the present invention has been described above. According to the wireless communication system according to the present embodiment, the signals transmitted by frequency-multiplexing the signals of the subchannels are received and demodulated, and frequency-demultiplexed into the signals of the subchannels. Gain control is performed on the channel signal. Thereby, even when the propagation path condition of the radio wave differs for each subchannel, gain control is performed on the signal of each subchannel, so that gain control can be appropriately performed on the received signal.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

It is a functional block diagram which shows the radio | wireless communications system for multichannel transmission which concerns on embodiment of this invention. It is explanatory drawing which shows the result of the gain control by the radio | wireless communication apparatus which concerns on this embodiment. It is a functional lineblock diagram showing the automatic gain control part concerning a 1st embodiment. It is a functional block diagram which shows the automatic gain control part which concerns on 2nd Embodiment. It is explanatory drawing which shows the result of the gain control by the conventional radio | wireless communication apparatus. It is a functional block diagram which shows the conventional radio communication system for multichannel transmission to which the automatic gain control part is applied.

Explanation of symbols

10, 110 Transmitter 20, 120 Receiver 21, 121 Antenna unit 22, 122 Radio frequency (RF) demodulator 23, 123 Frequency combiner 24, 124, 130, 140 Automatic gain controller (AGC) unit 25, 125 Orthogonal demodulation unit 26, 126 Baseband demodulation unit 27, 127 Parallel / serial conversion unit

Claims (7)

In a wireless communication device that performs data transmission in parallel by a plurality of subchannels assigned different frequencies,
An antenna unit for receiving a signal transmitted by frequency-combining the signals of the subchannels;
A demodulator for demodulating the received signal;
A frequency demultiplexing unit that demultiplexes the demodulated signal into a signal of each subchannel;
An automatic gain control unit that is provided corresponding to each of the sub-channels and performs automatic gain control on a signal of each of the corresponding sub-channels that is frequency-demultiplexed;
A variable gain amplifier for amplifying the signal of each subchannel to a predetermined level;
A power fluctuation storage unit for storing a prediction pattern representing the received power of the signal of each subchannel measured in advance along the movement path;
A variation pattern representing the reception power of each subchannel signal actually measured at a certain time is compared with the prediction pattern by pattern matching, and reception of each subchannel signal actually measured at that time is received. A reception power prediction unit that identifies which portion of the prediction pattern of power corresponds to the received power and predicts the reception power of the signal of each subchannel at the next time based on the prediction pattern;
A control voltage generator for generating a control voltage for amplifying the signal of each subchannel to a predetermined level based on the received power of the signal of each predicted subchannel, and supplying the control voltage to the variable gain amplifier;
A wireless communication device comprising:   The radio communication apparatus according to claim 1, wherein the radio communication apparatus is applied to a mobile communication system that performs radio communication between a mobile station and a base station for which a movement path is determined. The prediction pattern is a variation pattern corresponding to a position change of the mobile station,
The radio communication apparatus according to claim 2, wherein the reception power prediction unit identifies a corresponding position in the prediction pattern of the reception power of the signal of each subchannel actually measured at the time.
The automatic gain controller is
A control voltage generator for generating a control voltage for controlling the signal of each subchannel to a predetermined level based on the amplified signal of each subchannel, and supplying the control voltage to the variable gain amplifier;
The wireless communication apparatus according to claim 1, further comprising: A demodulator that is provided corresponding to each subchannel and demodulates a signal of each corresponding subchannel subjected to the automatic gain control at a frequency assigned to each subchannel;
A baseband demodulator that is provided corresponding to each subchannel and demodulates a signal of each corresponding subchannel demodulated at a frequency assigned to each subchannel;
A parallel-serial converter that converts the baseband demodulated signal of each subchannel into a baseband signal;
The wireless communication apparatus according to claim 1, further comprising: In a wireless communication system that performs data transmission in parallel by a plurality of subchannels assigned different frequencies from a wireless communication device that is a transmission side to a wireless communication device that is a reception side,
The wireless communication device on the receiving side is
An antenna unit that receives a signal transmitted from a wireless communication device on the transmission side by frequency-combining the signals of the subchannels;
A demodulator for demodulating the received signal;
A frequency demultiplexing unit that demultiplexes the demodulated signal into a signal of each subchannel;
An automatic gain control unit that is provided corresponding to each of the sub-channels and performs automatic gain control on a signal of each of the corresponding sub-channels that is frequency-demultiplexed;
A variable gain amplifier for amplifying the signal of each subchannel to a predetermined level;
A power fluctuation storage unit for storing a prediction pattern representing the received power of the signal of each subchannel measured in advance along the movement path;
A variation pattern representing the reception power of each subchannel signal actually measured at a certain time is compared with the prediction pattern by pattern matching, and reception of each subchannel signal actually measured at that time is received. A reception power prediction unit that identifies which portion of the prediction pattern of power corresponds to the received power and predicts the reception power of the signal of each subchannel at the next time based on the prediction pattern;
A control voltage generator for generating a control voltage for amplifying the signal of each subchannel to a predetermined level based on the received power of the signal of each predicted subchannel, and supplying the control voltage to the variable gain amplifier;
A wireless communication system comprising: In a radio communication method applied to a radio communication apparatus that performs data transmission in parallel by a plurality of subchannels assigned different frequencies from a radio communication apparatus on a transmission side to a radio communication apparatus on a reception side ,
The radio communication device on the receiving side receives the signal transmitted from the radio communication device on the transmitting side by frequency-combining the signals of the subchannels, demodulates the received signal, and demodulates the demodulated signal. The signal is frequency-demultiplexed into the signals of the subchannels, and automatic gain control is performed on the signals of the subchannels after the frequency demultiplexing, and the signals of the subchannels measured in advance along the movement path A prediction pattern representing received power is stored, and a variation pattern representing the received power of each subchannel signal actually measured at a certain time is compared with the predicted pattern by pattern matching. To determine which part of the prediction pattern of the received power of the signal of each sub-channel to be measured corresponds to the prediction pattern To predict the reception power of the signal of each subchannel at the next time based on, and amplify the signal of each subchannel to a predetermined level based on the predicted reception power of the signal of each subchannel And a signal for each subchannel is amplified to a predetermined level based on the control voltage.

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