JP2006101238A - Receiving device, communication terminal device, communication system and gain control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a deterioration in communication quality at the time of receive by a second communication system when a first communication system and the second communication system are managed which is different from the first one. <P>SOLUTION: A time measurement unit 113 measures time longer than one frame time of a first communication system in an TDM method after a jamming wave tolerance mode is selected by an operation mode selecting signal. In a mode setting unit 112, the jamming wave tolerance mode is held during the time measurement after a frame time measurement signal generated from the time measurement unit 113 is entered, and at the time except this an operation mode setting signal is generated based on a BER deterioration judgement signal and a receive power value judgement signal. In a gain control unit 166, a second intermediate frequency power value signal and an operation mode setting signal are entered, and thereby a gain control signal for controlling the gain of a variable gain amplifier 153 is generated, and at the same time a receive electric field intensity signal is generated as electric field intensity of a receive signal entered from a receive antenna 151. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus, a communication terminal apparatus, a communication system, and a gain control method. For example, a UMTS (Universal Mobile Telecommunications System) system and a GSM (Global System for) whose standards are respectively defined by 3GPP (3rd Generation Partnership Project) Mobile Communications) and a receiving apparatus applicable to a UMTS system in which a GSM or PDC communication system is operated in the same frequency band such as the UMTS system and a PDC (Personal Digital Cellular) system operated in Japan The present invention relates to a communication terminal device, a communication system, and a gain control method.

  2. Description of the Related Art In recent years, with the spread of communication systems, in order to increase frequency utilization efficiency, time division multiplexing TDM (Time Division) has been changed from FDM (Frequency Division Multiplex) which is multiplexed in the frequency domain with the times. There has been a transition to a Multiplex (Time Division Multiplexing) method and a CDM (Code Division Multiplex) method using a spreading technique using orthogonal codes.

  For example, in the field of mobile communication, there is a demand for services that respond to the increase in the number of users and services with higher communication speeds. Therefore, it is required to shift to a new communication method in the same frequency band in order to further improve the frequency utilization efficiency as compared with the communication system that has been operated conventionally. In that case, it is necessary to change the terminal device of the user who has conventionally used the system so as to correspond to the new method. However, since it is not desirable to give the user a burden to replace the terminal device corresponding to the new method, assuming that the update due to replacement of the user's terminal device will proceed, the user terminal device will be provided with a transition period to the new method Until the update is completed, it is desirable that the conventional method be operated at the same time. In addition, it takes a lot of time to install the base station equipment corresponding to the new system, and it is not easy to change the base station equipment of all service areas operated by the conventional system at the same time. Immediately after the start of operation, the service area is often limited to a specific narrow range. Therefore, it is desired that both the conventional method and the new method can be operated simultaneously in the same frequency band.

  In this case, when communication is performed using a new communication system, a conventional communication signal may exist as an interference wave. For example, for the new method, if the communication signal of the conventional method becomes an interference wave, and the communication quality of the new method cannot ensure the original quality, the impression that the communication quality of the new method is bad spreads to the user side , The user's willingness to purchase a terminal device compatible with the new method may be impaired. That is, when shifting to the new system, it must be avoided that the communication quality of the new system deteriorates due to the interference wave caused by the communication signal of the conventional system.

In this way, when there is an adjacent interference wave, in order to suppress the deterioration of communication quality due to the interference wave, for example, the reception electric field strength and the BER (Bit Error Rate) are measured, and the reception electric field strength is high. BER monitoring that estimates that the BER is caused by the saturation of the circuit due to jamming, etc., reduces the gain of the variable gain amplifier, and suppresses the saturation of the circuit to improve the jamming characteristics A type receiving apparatus is known (for example, Patent Document 1).
JP-A-8-18469

  However, the conventional apparatus receives a signal in a static environment so that the received signal component does not fall below the dynamic range of the receiving circuit even if the received signal level is suddenly reduced by, for example, 10 dB due to fading or the like. Therefore, the operation is performed in the fading resistance mode in which the deterioration of the communication quality is suppressed by setting the gain higher by 10 dB or more than the minimum circuit gain required. In addition, when an interference wave is input, after detecting that BER deterioration has occurred, the interference wave whose deterioration in communication quality is suppressed by reducing the gain of the variable gain amplifier by, for example, 10 dB to suppress circuit saturation. Operates in resistance mode. Here, it is assumed that a first communication system that is a TDM system and a second communication system different from the first communication system are operated simultaneously in the same frequency band. The receiving device of the second communication system operates the first communication system at a nearby frequency when communicating with the second communication system, and the interference wave is also input from the receiving antenna. . That is, an interference wave exists in the vicinity frequency. In the case of the conventional receiving apparatus, after detecting BER degradation caused by the fluctuation of the signal level, switching between the interference wave resistance mode and the fading resistance mode is performed for each frame of the TDM system. Needs to detect communication quality degradation such as BER degradation. In addition, after detecting the deterioration of the communication quality, the communication mode such as BER deteriorates until the operation mode is switched to the interference wave resistance mode and the automatic gain control is stabilized.

  Here, since the first communication system is a TDM system, the signal level of the interference wave largely fluctuates in synchronization with the frame timing of the TDM system. Therefore, the conventional receiving apparatus has a problem that, when such a TDM interference wave is input, the BER deteriorates for each TDM frame for the above-described reason.

  FIG. 9 shows the signal strength and the state of each part of the BER monitoring type receiving apparatus assuming the case where an interference wave exists in a frequency band close to the desired wave in the conventional apparatus. FIG. 9A shows the slot configuration of the first communication system that is the TDM system. Here, a state is shown in which transmission is performed in the fifth slot of the first communication system, but transmission may be performed in a plurality of slots. FIG. 9B shows a diagram of the transmission signal level of the base station of the first communication system. Since transmission is performed in the fifth slot shown in FIG. 9A, the transmission signal level of the base station at that timing is higher than at other timings.

  FIG. 9C shows the transmission signal level of the base station of the second communication system. The second communication system is a communication system in which the transmission signal does not change greatly for each slot, for example, as in the CDM system. FIG. 9D shows the first intermediate frequency signal level (when the fading tolerance mode is fixed). As described above, when the gain of the variable gain amplifier is fixed in the state in the fading tolerance mode, when an interference wave having a frequency near the strong electric field is input, for example, as in periods 1071a, 1071b, and 1071c, A / A period in which a circuit such as a D converter is saturated occurs. In this case, BER degradation occurs due to the reason that the signal component of the desired wave is distorted. Note that “below the dynamic range of the receiving circuit” means, for example, a state in which the received signal level is lower than the A / D converter quantization noise level in FIG.

  FIG. 9E shows the first intermediate frequency signal level (when the operation mode switching function is in operation), and FIG. 9F shows the BER of the second communication system.

  When an interference wave from the first communication system is input, the BER is reduced as in the BER degradation periods 1075a, 1075b, and 1075c in the period in which the A / D converter is saturated as in the periods 1074a, 1074b, and 1074c. Since deterioration occurs, the BER calculation unit detects deterioration in communication quality. For example, a transmission signal is output from the base station in the first frame of the first communication system. The transmission signal is an interference wave in the second communication system, and the BER deteriorates in the period 1074a. That is, by detecting that the BER has deteriorated even though the received electric field strength is high, the circuit is prevented from being saturated and the BER is improved by shifting to the interference wave resistance mode. When the transmission of the first frame of the first communication system is completed, there is no interfering wave. Therefore, a decrease in the received electric field strength is detected, and it is detected that there is no BER deterioration, and the mode shifts to the fading resistance mode. To do. For this reason, at the transmission timing of the second frame of the first communication system, the BER is deteriorated as in the case of the first frame. That is, when the first communication system that is the TDM system is operated at a frequency close to that of the second communication system to be received, BER degradation occurs at each frame timing of the first communication system. There is a problem of end.

  The present invention has been made in view of such a point, and in the case where the first communication system and a second communication system different from the first communication system are operated, the communication quality at the time of reception of the second communication system is reduced. It is an object of the present invention to provide a receiving device, a communication terminal device, a communication system, and a gain control method that can be reduced.

  The receiving apparatus of the present invention obtains the variable gain amplification means for amplifying the received signal of the second communication system operated in the frequency band close to the frequency band of the first communication system, and the received electric field strength of the received signal. Received electric field strength signal calculation means, communication quality calculation means for detecting communication quality of the received signal, and the received signal of the first communication system becomes an interference wave with respect to the received signal of the second communication system The time measurement is started by detecting the deterioration of the communication quality due to the time, and the time measuring means for measuring a predetermined time longer than one frame of the first communication system and the received electric field strength signal calculating means The variable gain amplifying means amplifies the received signal based on the received electric field strength, the communication quality detected by the communication quality calculating means, and the time measured by the time measuring means. It adopts a configuration comprising a mode setting means for controlling a gain of time that, the.

  The communication system of the present invention includes a base station apparatus that transmits a signal of the first communication system and a signal of the second communication system operated in a frequency band close to the frequency band of the first communication system, and the base A communication terminal device that receives a signal of the first communication system and a signal of the second communication system transmitted from a station device, wherein the communication terminal device is the second communication system. Variable gain amplifying means for amplifying the received signal, received field strength signal calculating means for obtaining the received field strength of the received signal, communication quality calculating means for detecting the communication quality of the received signal, and the first communication system Time measurement is started after the deterioration of the communication quality due to the received signal becoming an interference wave with respect to the received signal of the second communication system, and the first communication is started. A time measuring means for measuring a predetermined time longer than one frame of the system; a received electric field strength obtained by the received electric field strength signal calculating means; a communication quality detected by the communication quality calculating means; And a mode setting means for controlling the gain when the received signal is amplified by the variable gain amplifying means based on the time measured in this manner.

  The gain control method of the present invention includes a step of amplifying a reception signal of a second communication system operated in a frequency band close to a frequency band of the first communication system, and a step of obtaining a reception electric field strength of the reception signal. Detecting the communication quality of the received signal, and detecting the deterioration of the communication quality due to the received signal of the first communication system becoming an interference wave with respect to the received signal of the second communication system. From the step of measuring a predetermined time longer than one frame of the first communication system, the received electric field strength, the detected communication quality, and the time measured And a step of controlling a gain when a received signal is amplified.

  According to the present invention, when a first communication system and a second communication system different from the first communication system are operated, it is possible to reduce deterioration of communication quality at the time of reception of the second communication system.

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

  FIG. 1 is a block diagram showing a configuration of receiving apparatus 111 according to an embodiment of the present invention.

  The receiving device 111 outputs a time longer than one frame time of the first communication system of the TDM system after the operation mode selection signal selects the interference wave resistance mode, and the time measuring unit 113 outputs the time. A mode setting unit 112 that receives the frame timing signal and maintains the interference wave tolerance mode during timing, and otherwise outputs an operation mode setting signal based on the BER deterioration determination signal and the received power value determination signal. A reception antenna 151 that receives the reception signal, a reception filter 152 that removes unnecessary frequency components from the reception signal received by the reception antenna 151, and an amplifier that amplifies the reception signal from which unnecessary frequency components have been removed, The variable gain amplifier 153 whose gain is controlled by the control signal and the received signal amplified by the variable gain amplifier 153 in the first intermediate A first frequency converter 154 that converts the frequency into a wave number signal, a first intermediate frequency filter 156 that band-limits the first intermediate frequency signal, and a first intermediate frequency signal that is band-limited by the first intermediate frequency filter 156 The first intermediate frequency amplifier 157, the second frequency converter 158 that converts the first intermediate frequency signal amplified by the first intermediate frequency amplifier 157 into the second intermediate frequency signal, and the second intermediate frequency signal. A quadrature demodulator 160 that outputs a second I signal and a second Q signal, which are baseband signals that are quadrature demodulated and converted into baseband signals and band-limited, and band-limited. A decoder 162 that decodes the baseband signal and converts it into decoded data that is a digital data string, and counts the number of errors included in the decoded data. A baseband unit 161 including a BER calculation unit 163 that outputs a BER signal that is a BER is obtained, and a second I signal and a second Q signal are input, and the power value is obtained. The power calculation unit 164 that outputs the second intermediate frequency power value signal that is a proportional value, and the second intermediate frequency power value signal and the operation mode setting signal are input to control the gain of the variable gain amplifier 153. The gain control unit 166 outputs a gain control signal and outputs a received electric field strength signal that is the electric field strength of the received signal input from the receiving antenna 151.

  Next, the configuration of the mode setting unit 112 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a detailed configuration of the mode setting unit 112.

  The mode setting unit 112 compares the magnitude relationship between the BER signal and the BER threshold value 202, which is a BER threshold value, and compares the magnitude relationship between the comparison unit 201 that outputs the BER deterioration determination signal and the received electric field strength signal and the electric field strength threshold value 204. And the comparison unit 203 that outputs the received power value determination signal, and the BER deterioration determination signal and the received power value determination signal are input, whereby the power of the second intermediate frequency signal input to the power calculation unit 164 And a determination unit 205 that outputs an operation mode setting signal for setting a target value. The determination unit 205 maintains the interference wave tolerance mode while the frame timing signal is being measured, and outputs an operation mode setting signal based on the BER deterioration determination signal and the received power value determination signal otherwise. It has a function to do.

  That is, when the received electric field strength is a predetermined electric field strength and the communication quality obtained by the BER calculation unit 163 is equal to or lower than the preset quality, the mode setting unit 112 outputs an operation mode setting signal and also counts time 113 controls the mode setting unit 112 so as to start a time measuring operation based on the operation mode setting signal and to maintain the output of the output operation mode setting signal for a predetermined time.

  Therefore, when the mode is switched to the jamming wave resistance mode, the timer 113 can operate in the jamming wave resistance mode for longer than one frame time of the first communication system. In the frame, circuit saturation due to disturbing waves can be avoided, so that BER degradation can be reduced.

  Next, the configuration of quadrature demodulator 160 will be described with reference to FIG. FIG. 3 is a block diagram showing a detailed configuration of the quadrature demodulator 160.

  The quadrature demodulator 160 performs an A / D converter 501 that samples the input second intermediate frequency signal, quadrature demodulates the sampled second intermediate frequency signal, and outputs a first I signal and a first Q signal. And a channel filter unit 505 for band-limiting the first I signal and the first Q signal and outputting the second I signal and the second Q signal, respectively. The quadrature demodulator 502 converts the sampled second intermediate frequency signal into an I signal and outputs a first I signal, and converts the first Q signal into a Q signal. A Qch mixer 504 for output, and a channel filter unit 505 band-limits the first I signal and outputs a second I signal; and a band-limit for the first Q signal and the second Q signal. Output Q signal Constituted by the Qch filter 507.

  Next, the configuration of the power calculation unit 164 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a detailed configuration of the power calculation unit 164.

  The power calculation unit 164 is input with the second I signal and the second Q signal, and includes a square calculation unit 601 that squares the instantaneous value, and the square calculation unit 601 includes the second I signal. An Ich square calculator 606 that calculates the square value of the instantaneous value of the signal, and a power calculation unit Qch square calculator 607 that calculates the square value of the instantaneous value of the second Q signal. The second power integrated value is obtained by adding the square value of the instantaneous value, the square value of the second instantaneous value of the Q signal, and the first power integrated value stored in the added value storage unit 603. , An adder 602 that stores the second power integral value, an addition value storage unit 603 that outputs the first power integral value, and a predetermined integration time for obtaining the first power integral value A timer 604 for timing and outputting a reset signal for resetting the added value of the added value storage unit 603; It constituted by the power value holding unit 605 which holds the first power integration value immediately before as they are entered.

  By adopting the above configuration, the power calculation unit 164 performs the first power integration in which the square value of the instantaneous value of the second I signal and the second Q signal is integrated at a predetermined time by the timer unit 604. The value can be determined. When a predetermined time elapses, the power values of the second I signal and the second Q signal input to the power calculation unit 164 from the power value holding unit 605 to the time counted by the time counting unit 604 are set. A proportional second intermediate frequency power value signal can be output.

  Next, the configuration of the BER calculation unit 163 will be described with reference to FIG. FIG. 5 is a block diagram showing a detailed configuration of the BER calculation unit 163.

  The BER calculation unit 163 receives the decoded data, detects an error included in the decoded data, outputs an error detection signal when there is an error, and counts the number of decoded data. The bit counter 702 that outputs an error counter reset signal when the number of bits is counted, and the number of error detection signals output from the error detection unit 701 are counted, and the counter value is obtained by inputting the error counter reset signal. Is configured by an error counter 703 that resets the BER and a BER holding unit 704 that holds the BER signal immediately before the error counter reset signal is input.

  By adopting the above configuration, the BER calculation unit 163 can count the number of errors counted by the error counter 703 among the decoded data having a predetermined number of bits counted by the bit number counter 702. That is, since the number of errors included in the decoded data is obtained out of the predetermined number of bits, the value is proportional to the BER. Also, the bit number counter 702 counts the number of bits of the input decoded data, and when the predetermined number of bits is reached, the BER holding unit 704 holds the immediately preceding BER signal, so the BER indicating the communication quality of the decoded data A signal can be output.

  Next, the configuration of the gain control unit 166 will be described with reference to FIG. FIG. 6 is a block diagram showing a detailed configuration of the gain control unit 166.

  The gain control unit 166 selects either the first target value 903 or the second target value 904 based on the second intermediate frequency power value signal and the operation mode setting signal, and outputs the second intermediate frequency power value signal. The selection means 902 for outputting the target value, the comparison unit 901 for comparing the second intermediate frequency power value signal and the target value of the second intermediate frequency power value signal, and outputting the comparison result, and the comparison result is the second intermediate A gain control signal generator 905 that controls the gain control signal so that the difference between the frequency power value signal and the target value of the second intermediate frequency power value signal approaches zero; and the target value of the second intermediate frequency power value signal A reception field strength signal calculation unit 906 that outputs a reception field strength signal that is the field strength of the reception signal input from the reception antenna 151 from the gain control signal.

  By adopting the above configuration, the gain control unit 166 selects the target value of the second intermediate frequency power value signal from the first target value 903 and the second target value 904 according to the operation mode setting signal, and performs gain control. I do.

  FIG. 7 is a diagram illustrating a state of each unit in the reception device 111.

  7, (a) to (d) are the same as those in FIG. 9. Therefore, reference numerals 370 a to 370 c and 371 a to 371 c in FIG. 7 are the same as reference numerals 1070 a to 1070 c and 1071 a to 1071 in FIG. 9, respectively. It is the same as 1071c.

  FIG. 7 (e) is a diagram showing changes in the first intermediate frequency signal level, FIG. 7 (f) is a diagram showing changes in the BER of the second communication system, and FIG. It is a figure which shows the change of a frame timing signal.

  In FIG. 7E, the first intermediate frequency signal level is saturated in the period 372a due to the input of the interference wave of the first communication system, and at the same time in the period 373a. Deterioration of BER occurs, thereby switching to the interference wave tolerance mode. Further, the timing of the timing unit 113 is started from this timing. The timing unit 113 outputs a frame timing signal indicating that the time is being measured while measuring a time longer than one frame time of the first communication system that is the TDM system, and operates in the interference wave resistance mode during that time. For this reason, saturation due to interference waves does not occur, so BER degradation does not occur. Since the timer 113 measures a time longer than one frame time of the first communication system, this state maintains the interference wave resistance mode even at the timing when the transmission signal of the next frame of the first communication system is transmitted. is doing. For this reason, circuit saturation does not occur and BER degradation does not occur. That is, there is no BER degradation caused by circuit saturation due to the transmission signal of the second frame that has occurred in the conventional receiver. Therefore, the BER characteristic is improved as compared with the conventional receiving apparatus.

  FIG. 8 is a diagram showing a communication system 800 according to the present embodiment. FIG. 8 is a diagram illustrating a communication system in which a signal from each base station device operated in a different communication system is received by the reception device 111 of FIG. 1 provided in the communication terminal device 801. The communication system and the second communication system are shown to be operated in the same area.

  A base station 802 operated in the first communication system transmits a base station transmission signal of the first communication system from a base station antenna 803. Similarly, the base station 804 operated in the second communication system transmits a base station transmission signal of the first communication system from the base station antenna 805. In the base station transmission signal of the first communication system, the base station is installed and the transmission power is set so that communication is possible up to the service area # 810 range of the first communication system. The station transmission signal is assumed to have a base station installed and transmission power set so that communication is possible up to the service area # 811 of the second communication system.

  The communication terminal apparatus 801 performs communication in an area # 812 indicated by hatching in FIG. 8 where the service area # 810 of the first communication system and the service area # 811 of the second communication system overlap. is there. The communication terminal apparatus 801 uses a signal (desired wave) to receive the base station transmission signal of the second communication system, and the base station transmission signal of the first communication system is an interference wave that causes interference in the communication. At this time, the base station transmission signal of the first communication system is shown in FIG. 7B, and the base station transmission signal of the second communication system is shown in FIG. 7C.

  By adopting the configuration of the communication system 800 using the communication terminal apparatus 801 including the receiving apparatus 111 of the present invention, the service area # 810 of the first communication system and the service area # 811 of the second communication system are used. When the first communication system and the second communication system are operated in the same region, the frequency of the base station transmission signal of the first communication system becomes the frequency of the base station transmission signal of the second communication system. Even in the case of close proximity, it is possible to provide a communication service in which deterioration of communication quality of the second communication system caused by a base station transmission signal of the first communication system is reduced.

  In FIG. 8, the base station device 802 and the base station device 804 are shown installed in different places. However, the present invention is not limited to this, and the first communication system base station transmission signal from the same base station device You may make it transmit a 2nd communication system base station transmission signal. Even in this case, there is a region where the service area of the first communication system and the service area of the second communication system overlap each other, and the same effect can be obtained.

  Note that, when the timing of the timing unit 113 is completed, the operation mode is switched to the fading resistance mode. Therefore, in FIG. 9, BER degradation occurs in the third frame, but the time measured by the timing unit 113 is the TDM method. The same effect can be obtained when the frame length is longer than one frame time of the first communication system, for example, four frame times. In this case, BER degradation due to circuit saturation can be avoided during a period of 4 frames of the first communication system after detecting degradation due to interference waves.

  Note that the time longer than one frame time described here includes, for example, a time delay required to obtain the BER. For example, when the BER is obtained simultaneously with the completion of the transmission slot of the jamming wave Since it is necessary to keep the time until the next transmission slot of the jamming wave in the jamming wave resistant mode, in that case, one frame time may be counted. In addition, when switching to the jamming wave tolerance mode at the moment when BER degradation occurs, the time obtained by adding one slot time to one frame time may be counted.

  In addition, since the time per frame and the time per slot of the first communication system which is the TDM system used in the same frequency band are known in advance, the time measured by the time measuring unit 113 is the same in advance. It can be easily set based on the specification of the TDM system used in the frequency band.

  In this embodiment, BER is used when monitoring communication quality. However, an EVM (Error Vector Magnitude), S / N ratio, or the like may be used as an index indicating communication quality.

  Thus, according to the present embodiment, when the first communication system that is the TDM system and the second communication system other than the TDM system are operated in the same frequency band, The receiving device 111 of the present invention having tolerance is variable by switching the target value of the power value of the second intermediate frequency signal when detecting that the communication quality has deteriorated due to the interference wave from the first communication system. Controlling the gain of the gain amplifier 153 avoids circuit saturation. After switching the target value of the second intermediate frequency signal, the timer 113 measures a time longer than the time per frame of the first communication system, and holds the target value of the second intermediate frequency signal during that time. Thus, even when an interference wave whose signal level greatly fluctuates in one frame period peculiar to the TDM system is present in the nearby frequency, it is possible to reduce the deterioration of the communication quality of the communication signal of the second communication system.

  The present invention is particularly suitable for use in a receiving apparatus, a communication terminal apparatus, a communication system, and a gain control method in which a first communication system and a second communication system different from the first communication system are operated in the same frequency band. It is.

The block diagram which shows the structure of the receiver which concerns on embodiment of this invention The block diagram which shows the structure of the mode setting part which concerns on embodiment of this invention The block diagram which shows the structure of the orthogonal demodulator which concerns on embodiment of this invention The block diagram which shows the structure of the electric power calculating part which concerns on embodiment of this invention The block diagram which shows the structure of the BER calculation part which concerns on embodiment of this invention. The block diagram which shows the structure of the gain control part which concerns on embodiment of this invention The figure which shows the state of each part of a receiver The figure which shows the communication system which concerns on embodiment of this invention The figure which shows the state of each part of the conventional receiver

Explanation of symbols

DESCRIPTION OF SYMBOLS 111 Receiver 112 Mode setting part 113 Time measuring part 152 Reception filter 153 Variable gain amplifier 154 1st frequency converter 156 1st intermediate frequency filter 157 1st intermediate frequency amplifier 158 2nd frequency converter 160 Quadrature demodulator 161 Baseband Unit 162 decoder 163 BER calculation unit 164 power calculation unit 166 gain control unit

Claims (5)

Variable gain amplification means for amplifying a received signal of a second communication system operated in a frequency band close to the frequency band of the first communication system;
A received electric field strength signal calculating means for obtaining a received electric field strength of the received signal;
Communication quality calculation means for detecting the communication quality of the received signal;
The timing measurement is started after the deterioration of the communication quality due to the reception signal of the first communication system becoming an interference wave with respect to the reception signal of the second communication system, and the first communication system. A time measuring means for measuring a predetermined time longer than one frame of
Based on the received electric field strength obtained by the received electric field strength signal calculating means, the communication quality detected by the communication quality calculating means, and the time measured by the time measuring means, the variable gain amplifying means Mode setting means for controlling the gain when the received signal is amplified,
A receiving apparatus comprising:   2. The receiving apparatus according to claim 1, wherein the mode setting means controls the gain within the time measured by the time measuring means to be lower than before the time measurement is started by the time measuring means. .   A communication terminal device comprising the receiving device according to claim 1. A base station device for transmitting a signal of the first communication system and a signal of the second communication system operated in a frequency band close to the frequency band of the first communication system;
A communication system having a communication terminal device that receives the signal of the first communication system and the signal of the second communication system transmitted from the base station device,
The communication terminal device
Variable gain amplification means for amplifying a received signal of the second communication system;
A received electric field strength signal calculating means for obtaining a received electric field strength of the received signal;
Communication quality calculation means for detecting the communication quality of the received signal;
The timing measurement is started after the deterioration of the communication quality due to the reception signal of the first communication system becoming an interference wave with respect to the reception signal of the second communication system, and the first communication system. A time measuring means for measuring a predetermined time longer than one frame of
Based on the received electric field strength obtained by the received electric field strength signal calculating means, the communication quality detected by the communication quality calculating means, and the time measured by the time measuring means, the variable gain amplifying means Mode setting means for controlling the gain when the received signal is amplified,
A communication system comprising: Amplifying a received signal of a second communication system operated in a frequency band close to the frequency band of the first communication system;
Obtaining a received electric field strength of the received signal;
Detecting the communication quality of the received signal;
The timing measurement is started after the deterioration of the communication quality due to the reception signal of the first communication system becoming an interference wave with respect to the reception signal of the second communication system, and the first communication system. Measuring a predetermined time longer than one frame of
Controlling the gain in amplifying the received signal based on the obtained received electric field strength, the detected communication quality and the time measured;
A gain control method comprising:

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