JP2005073078A - Communication apparatus and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus and communication method for realizing power consumption reduction in the communication apparatus which uses a plurality of different frequency bands to perform data communications. <P>SOLUTION: When it is possible to receive signals using a second frequency band (e.g. a frequency band to be used in a wireless LAN), a communication apparatus 1a comprising a multi-mode terminal transmits/receives signals using the second frequency and stops supplying power to a high frequency part 3a and a signal processing part 5a. When it is not possible to transmit/receive signals using the second frequency band, the communication apparatus 1a transmits/receives signals using a first frequency band (e.g. a frequency band to be used for a cellular phone) and stops supplying power to a signal processing part 5b of a second transmitting/receiving part. Namely, the communication apparatus 1a stops supplying power to the unnecessary transmitting/receiving part in response to a receiving state, thereby reducing power consumption. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication device and a communication method for transmitting and receiving signals using a plurality of different frequency bands.

  In recent years, a device called a so-called multi-mode terminal device that performs data communication using a plurality of different frequency bands has been developed. For example, the frequency band used by the communication device includes a frequency band (800 MHz band) used by a mobile phone terminal, a frequency band (1.9 GHz band) used by a PHS (Personal Handy-phone System), and a frequency band used by a wireless LAN (2 .4 GHz band, 5.2 GHz band) and the like. In the above communication device, the reception states of all frequency bands to be used are monitored by a plurality of signal processing units provided therein, and switching of frequency bands for data communication is generally performed by a CPU (central processing unit). Device) (see, for example, Patent Document 1: hereinafter referred to as the first prior art).

On the other hand, there is a wireless communication system that achieves low power consumption (see, for example, Patent Document 2: hereinafter referred to as the second prior art). In this wireless communication system, power consumption is reduced by turning on and off the power supply to the amplifier of the receiving circuit in accordance with the received high-frequency signal level.
Japanese Patent Laid-Open No. 11-252006 JP 2002-185342 A

  However, in the first prior art, since it is necessary to constantly monitor the reception states of all frequency bands used by the communication device by the respective signal processing units, the power consumption for monitoring increases. In addition, there is a problem that the power consumption further increases as the frequency band used by the communication apparatus increases.

  Further, the second prior art has one frequency band that can be used (that is, one modulation / demodulation method), and can be applied to a communication apparatus that performs data communication using a plurality of different frequency bands. Therefore, it has been impossible to achieve appropriate low power consumption for the communication device.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a communication device and a communication method that realize low power consumption in a communication device that performs data communication using a plurality of different frequency bands.

  In order to achieve the above object, the present invention employs the following configuration. Note that reference numerals and the like in parentheses indicate correspondence with embodiments described later to help understanding of the present invention, and do not limit the scope of the present invention.

  The communication device (1a) of the present invention transmits and receives signals using a plurality of different frequency bands. The communication device includes a first high-frequency unit (3a), a first signal processing unit (5a), a second high-frequency unit (3b), a second signal processing unit (5b), a power supply unit (7), and a switch unit. (8a) and a signal level detector (6a). The first high-frequency unit transmits and receives signals using the first frequency band (800 MHz band and 1.9 GHz band). The first signal processing unit performs predetermined signal processing on a signal transmitted and received by the first high frequency unit. The second high-frequency unit transmits and receives a signal using a second frequency band (2.4 GHz band or 5.2 GHz band) different from the first frequency band. The second signal processing unit performs predetermined signal processing on the signal transmitted and received by the second high frequency unit. The power supply unit supplies power to at least the first and second high-frequency units and the first and second signal processing units. The switch unit connects / disconnects the power supply lines (first and second SWs 81a and 82a) from the power supply unit to the first high-frequency unit and the first and second signal processing units, respectively. The signal level detection unit sets the first reception level of the signal using the second frequency band received by the second high frequency unit (communication device 1a performing the operation of step S11; hereinafter, only the step number is shown). Accordingly, the connection / disconnection operation of the switch unit is controlled (S12 to S18). When the first reception level is equal to or higher than a predetermined value (S12), the signal level detection unit supplies a power supply line (second SW 82a) from the power supply unit to the first high frequency unit and the first signal processing unit in the switch unit. (S14) The power supply line (first SW 81a) from the power supply unit to the second signal processing unit is connected (S13). The signal level detection unit disconnects the power supply line from the power supply unit to the second signal processing unit in the switch unit when the first reception level is less than the predetermined value (S12) (S17). The power supply line to the first high frequency unit and the first signal processing unit is connected (S16).

  When the first reception level is equal to or higher than a predetermined value and the first high frequency unit and the first signal processing unit are transmitting / receiving signals, the signal level detection unit is configured to switch the signal level detection unit after the transmission / reception processing ends. The power supply line from the power supply unit to the first high frequency unit and the first signal processing unit may be disconnected and the power supply line from the power supply unit to the second signal processing unit may be connected. Specifically, the area where the signal using the second frequency band can be received (the service area of the wireless LAN) is the area where the signal using the first frequency band can be received (cell phone or PHS). Service area) is relatively narrow.

  The communication device (1b) of the present invention may further include a third high frequency unit (3c) and a third signal processing unit (5c). The third high-frequency unit transmits and receives signals using a third frequency band (5.2 GHz band) different from the first (800 MHz band and 1.9 GHz band) and the second frequency band (2.4 GHz band). To do. The third signal processing unit performs predetermined signal processing on the signal transmitted and received by the third high-frequency unit. In this case, the power supply unit further supplies power to the third high-frequency unit and the third signal processing unit. The switch unit further connects / disconnects the power supply line (third SW 83b) from the power supply unit to the third signal processing unit. The signal level detection unit further receives the second reception level of the signal using the third frequency band received by the third high frequency unit (communication device 1b performing the operation of step S21; hereinafter, only the step number). The connection / disconnection operation of the switch unit is controlled according to (shown) (S22 to S32). When the first reception level is equal to or higher than the predetermined value (S22), the signal level detection unit is configured to supply a power supply line (the first power line) from the power supply unit to the first high frequency unit and the first and third signal processing units in the switch unit 1 and 3rd SW81b and 83b) are cut | disconnected (S24), and the electric power supply line (2nd SW82b) from a power supply part to a 2nd signal processing part is connected (S23). Further, the signal level detection unit is configured such that when the first reception level is less than a predetermined value (S22) and the second reception level is equal to or higher than the predetermined value (S26), the power source unit in the switch unit and the first high frequency unit The power supply line to the first and second signal processing units is disconnected (S28), and the power supply line from the power supply unit to the second signal processing unit is connected (S27). Further, the signal level detection unit connects the power supply line from the power supply unit to the second and third signal processing units in the switch unit when both the first and second reception levels are less than a predetermined value (S22, S26). Disconnect (S31) and connect the power supply line from the power supply unit to the first high frequency unit and the first signal processing unit (S30).

  When the first or second reception level is equal to or higher than a predetermined value and the first high-frequency unit and the first signal processing unit are performing signal transmission / reception processing, the signal level detection unit is configured to end the transmission / reception processing. The power supply line from the power supply unit to the first high-frequency unit and the first signal processing unit in the switch unit may be disconnected, and the power supply line from the power supply unit to the second or third signal processing unit may be connected. Absent. Specifically, the area where the signals using the second and third frequency bands can be received (wireless LAN service area) is more relative to the area where the signals using the first frequency band can be received. Narrow.

  Note that the present invention can also be realized as a communication method in the same manner as the communication apparatus described above.

  According to the communication apparatus of the present invention, a multi-mode terminal apparatus that performs data communication using a plurality of different frequency bands is configured, and power supply to unnecessary transmission / reception units is stopped according to the reception state to reduce power consumption. Can be realized. In addition, when the first high frequency unit and the first signal processing unit are performing transmission / reception processing of signals, the power supply to the first high frequency unit and the first signal processing unit is stopped after the transmission / reception processing is completed. Also good. In this case, low power consumption can be realized without interrupting transmission and reception of signals using the first frequency band. Further, a region where reception is narrow may be set as the second frequency band. In this case, if the area where reception is possible is preferentially transmitted / received to achieve low power consumption, and if the frequency band cannot be transmitted / received, data communication can be performed using a frequency band where the area where reception is possible is wide. it can.

  In addition, when the communication device of the present invention further includes a third high frequency unit and a third signal processing unit, a multimode terminal device that performs data communication using three different frequency bands is configured, and reception thereof Low power consumption can be realized by stopping power supply to unnecessary transmission / reception units according to the state. In addition, in this communication device, prioritization for transmission / reception with respect to three different frequency bands is performed, and for example, reception is possible in the order of the second frequency band → the third frequency band → the first frequency band. Therefore, low power consumption can be realized according to the reception state.

  Further, according to the communication method of the present invention, the same effect as that of the communication apparatus of the present invention described above can be obtained.

(First embodiment)
A communication apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of the communication apparatus.

  In FIG. 1, a communication device 1 a according to the first embodiment is connected to an information terminal device (not shown) such as a personal computer including a CPU (Central Processing Unit) 10. On the transmission side, the data output from the CPU 10 is transmitted. The information terminal device and the communication device 1a constitute a so-called multi-mode terminal device that performs data communication using a plurality of different frequency bands. For example, the communication device 1a is a card type wireless communication device connected to the information terminal device via a connector. Further, the communication device 1a may be configured as a device integrated with the information terminal device.

  The communication device 1a includes antennas 2a and 2b, high frequency units 3a and 3b, signal processing units 5a and 5b, a signal level detection circuit 6a, a power supply unit 7, and a switch (SW) unit 8a. . The antenna 2a, the high frequency unit 3a, and the signal processing unit 5a constitute a first transmission / reception unit that transmits / receives a signal using the first frequency band transmitted / received by the antenna 2a. For example, the first transmission / reception unit uses the frequency band (800 MHz band) used in the mobile phone terminal as the first frequency band and the frequency band (1.9 GHz band) used in PHS (Personal Handy-phone System). Send and receive. On the other hand, the antenna 2b, the high frequency unit 3b, and the signal processing unit 5b constitute a second transmission / reception unit that transmits and receives a signal using the second frequency band transmitted and received by the antenna 2b. For example, the second transmission / reception unit transmits and receives signals using a frequency band (2.4 GHz band, 5.2 GHz band) used in the wireless LAN as the second frequency band. Hereinafter, the configuration of the first transmission / reception unit will be described representatively.

  The high frequency unit 3a includes an LNA (Low Noise Amplifier) 32a, filters 33a and 35a, a mixer 34a, and a DEM (Demodulator) 36a on the receiving side. The high-frequency unit 3a includes a power amplifier 41a, a preamplifier 42a, a filter 43a, a mixer 44a, and a MOD (Modulator) 45a on the transmission side. The high frequency unit 3a includes a transmission / reception switching SW 31a and a synthesizer 46a between the reception side and the transmission side. On the reception side, the antenna 2a is connected to the signal processing unit 5a via serially connected transmission / reception switching SW31a → LNA 32a → filter 33a → mixer 34a → filter 35a → DEM 36a. On the other hand, on the transmission side, the signal processing unit 5a is connected to the antenna 2a via the MOD 45a, mixer 44a, filter 43a, preamplifier 42a, power amplifier 41a, and transmission / reception switching SW 31a connected in series. The synthesizer 46a is connected to the mixers 34a and 44a.

  The signal processing unit 5a includes a DAC (Digital Analog Converter) 51a, an ADC (Analog Digital Converter) 52a, and a signal processing circuit 53a. On the receiving side, the DEM 36 of the high-frequency unit 3a is connected to the CPU 10 via the ADC 52a → the signal processing circuit 53a. On the transmission side, the CPU 10 is connected to the MOD 45a of the high frequency unit 3a through the signal processing circuit 53a → the DAC 51a.

  Next, the operation of the first transmission / reception unit of the communication device 1a will be described. On the receiving side of the first transmitter / receiver, the signal using the first frequency band received by the antenna 2a is amplified by the LNA 32a, filtered by the filter 33a, and then input to the mixer 34a. The signal input to the mixer 34a is down-converted (generally several hundred MHz) by the mixer 34a based on the frequency oscillated by the synthesizer 46a, filtered by the filter 35a, and then input to the DEM 36a. The signal input to the DEM 36a is down-converted again by the DEM 36a, frequency-converted to a baseband level (generally several hundred MHz), and the demodulated signal is output to the ADC 52a. The signal input to the ADC 52a is converted to a digital signal by the ADC 52a, subjected to predetermined signal processing by the signal processing circuit 53a, and then output to the CPU 10.

  On the transmission side of the first transmission / reception unit, the data output signal output from the CPU 10 is subjected to predetermined signal processing by the signal processing circuit 53a, converted to an analog signal by the DAC 51a, and input to the MOD 45a. The signal input to the MOD 45a is modulated into a signal using the first frequency band based on the frequency oscillated by the synthesizer 46a by the MOD 45a and the mixer 44a, and input to the filter 43a. The signal input to the filter 43a is filtered by the filter 43a, amplified by the preamplifier 42a and the power amplifier 41a, and then transmitted from the antenna 2a via the transmission / reception switching SW 31a.

  The configuration and operation of the second transmitter / receiver configured by the high-frequency unit 3b and the signal processor 5b are the same as those of the first transmitter / receiver, except that a signal using a second frequency band different from the first frequency band is transmitted / received. This is the same as the transmitting / receiving unit. Therefore, the detailed description of the configuration and operation of the second transmission / reception unit is omitted, and hereinafter, the configuration unit of the second transmission / reception unit is referred to the reference symbol “a” given to the configuration unit of the first transmission / reception unit. The description will be made in place of “b”.

  The power supply unit 7 supplies power necessary for each component of the communication device 1a to operate. The power supplied from the power supply unit 7 may be supplied from the information terminal device or may be stored independently in the communication device 1a. In any case, the power supply operation of the power supply unit 7 is started when the information terminal device is turned on. The power supplied from the power supply unit 7 is supplied to the high frequency unit 3a and the signal processing units 5a and 5b via the SW unit 8a (shown by a thick solid line in FIG. 1), and the high frequency unit 3b and other components Are always supplied directly (not shown). The SW unit 8a includes a first SW 81a that turns on / off power supply from the power supply unit 7 to the signal processing unit 5b, and a second SW 82a that turns on / off power supply from the power supply unit 7 to the high frequency unit 3a and the signal processing unit 5a. have. The output on the receiving side from the high frequency unit 3b to the signal processing unit 5b (that is, the output from the DEM 36b to the ADC 52b) is connected to the signal level detection circuit 6a. The signal level detection circuit 6a detects the reception level from the high frequency unit 3b to the signal processing unit 5b (that is, the level of the baseband signal in the second frequency band), and based on the detection result, the first level of the SW unit 8a. And controls the operations of the second SWs 81a and 82a. Hereinafter, with reference to FIG. 2, an operation of supplying power in the communication device 1a will be described. FIG. 2 is a flowchart showing the operation of the communication device 1a.

  In FIG. 2, the signal level detection circuit 6a detects the reception level (that is, the level of the baseband signal in the second frequency band) received by the high frequency unit 3b (step S11). Since the signal level detection circuit 6a and the high frequency unit 3b are always directly supplied with power from the power supply unit 7 as described above, the signal level detection circuit 6a can always monitor the reception level. it can.

  Next, the signal level detection circuit 6a turns ON the first SW 81a of the SW unit 8a when the reception level detected in step S11 is equal to or higher than a predetermined threshold (step S12). As a result, power is supplied from the power supply unit 7 to the signal processing unit 5b (step S13). Then, the signal level detection circuit 6a turns off the second SW 82a of the SW unit 8a. Thereby, the power supply from the power supply unit 7 to the high frequency unit 3a and the signal processing unit 5a is stopped (step S14). And the 2nd transmission / reception part (namely, high frequency part 3b and signal processing part 5b) of the communication apparatus 1a transmits / receives the signal using a 2nd frequency band (step S15). Next, when communication is continued (step S19), the communication device 1a returns to step S11 and repeats the operation. When communication is terminated (step S19), the operation according to the flowchart ends.

  On the other hand, when the reception level detected in step S11 is less than the predetermined threshold (step S12), the signal level detection circuit 6a turns on the second SW 82a of the SW unit 8a. As a result, power is supplied from the power supply unit 7 to the high frequency unit 3a and the signal processing unit 5a (step S16). Then, the signal level detection circuit 6a turns off the first SW 81a of the SW unit 8a. Thereby, the power supply from the power supply unit 7 to the signal processing unit 5b is stopped (step S17). Then, the first transmission / reception unit (that is, the high frequency unit 3a and the signal processing unit 5a) of the communication device 1a performs transmission / reception of a signal using the first frequency band (step S18). Next, when communication is continued (step S19), the communication device 1a returns to step S11 and repeats the operation. When communication is terminated (step S19), the operation according to the flowchart ends.

  Thus, in the communication device 1a, when a signal using the second frequency band is receivable in the multimode terminal, the signal is transmitted / received using the second frequency band, and the first transmission / reception unit ( The power supply to the high frequency unit 3a and the signal processing unit 5a) is stopped to realize low power consumption. Further, in the communication device 1a, when a signal using the second frequency band cannot be received, the signal is transmitted / received using the first frequency band, and the signal is transmitted to the signal processing unit 5b of the second transmitting / receiving unit. The power supply is stopped to achieve low power consumption. That is, the communication device 1a realizes low power consumption by stopping power supply to unnecessary transmission / reception units according to the reception state. For example, the first frequency band is a frequency band used for mobile phone terminals (800 MHz band) and a frequency band used for PHS (1.9 GHz band), and the second frequency band is a frequency band used for wireless LAN (2.4 GHz). Band, 5.2 GHz band). In other words, there are generally few areas (wireless LAN service areas) where signals using the second frequency band can be received, and when the signals can be received, transmission / reception is performed with priority using the signals as much as possible. When the power supply to unnecessary transmission / reception units is stopped and a signal using the second frequency band cannot be received, the first frequency band (cell phone or PHS of the mobile phone or PHS) is relatively wide. This is an example in which data communication is performed using a service area to stop power supply to unnecessary signal processing units.

  Note that the communication device 1a may receive and transmit signals using the first frequency band under predetermined conditions, even if the signal using the second frequency band can be received. For example, when control by the CPU 10 is added to the signal level detection circuit 6a and signals are currently transmitted and received using the first frequency band (that is, the high frequency unit 3a and the signal processing unit 5a are used) The second SW 82a of the SW unit 8a may be turned on only during the period in use. Thereby, low power consumption can be realized without interrupting transmission and reception of signals using the first frequency band.

(Second Embodiment)
With reference to FIG. 3, a communication apparatus according to the second embodiment of the present invention will be described. Compared with the communication device 1a that transmits and receives signals using two different frequency bands described in the first embodiment, the communication device according to the second embodiment uses three different frequency bands. Send and receive signals. FIG. 3 is a block diagram showing the configuration of the communication apparatus.

  In FIG. 3, the communication device 1b according to the second embodiment is connected to an information terminal device (not shown) such as a personal computer including the CPU 10, and the reception side outputs the received signal to the CPU 10, and the transmission side In this case, data output from the CPU 10 is transmitted. The information terminal device and the communication device 1b constitute a so-called multi-mode terminal device that performs data communication using a plurality of different frequency bands. For example, the communication device 1b is a card-type wireless communication device that is connected to the information terminal device via a connector as in the first embodiment. The communication device 1b may be configured as a device integrated with the information terminal device.

  The communication device 1b includes antennas 2a, 2b and 2c, high frequency units 3a, 3b and 3c, signal processing units 5a, 5b and 5c, a signal level detection circuit 6b, a power supply unit 7 and a switch (SW) unit. 8b. Compared with the communication device 1a described in the first embodiment, the communication device 1b further includes a third transmission / reception unit including an antenna 2c, a high frequency unit 3c, and a signal processing unit 5c. A signal using the third frequency band to be transmitted / received is transmitted / received. In the communication device 1b, the configuration and operation of the signal level detection circuit 6b and the SW unit 8b are different. Therefore, in the description of the components of the communication device 1b, the same components as those of the communication device 1a described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The configuration and operation of the third transmission / reception unit configured by the high-frequency unit 3c and the signal processing unit 5c is to transmit and receive signals using a third frequency band different from the first and second frequency bands. Except for this, it is the same as the first and second transmission / reception units described in the first embodiment. Therefore, the detailed description of the configuration and operation of the third transmission / reception unit will be omitted. Hereinafter, the configuration unit of the third transmission / reception unit will be referred to by the reference symbol “a” given to the configuration unit of the first and second transmission / reception units. In addition, the description will be made by replacing “b” with reference symbol “c”.

  For example, in the communication device 1b, the first transmission / reception unit transmits / receives a signal using a frequency band (800 MHz band) used for a mobile phone terminal or a frequency band (1.9 GHz band) used for PHS as the first frequency band. Do. The second transmission / reception unit transmits and receives signals using a frequency band (2.4 GHz band) used in the wireless LAN as the second frequency band. The third transmission / reception unit transmits and receives signals using a frequency band (5.2 GHz band) used in the wireless LAN as the third frequency band.

  The power supply unit 7 supplies power necessary for the operation of each component of the communication device 1b. The power supplied from the power supply unit 7 may also be supplied from the information terminal device, or may be stored independently in the communication device 1b. In any case, the power supply operation of the power supply unit 7 is started when the information terminal device is turned on. The power supplied from the power supply unit 7 is supplied to the high frequency unit 3a and the signal processing units 5a, 5b, and 5c via the SW unit 8b (indicated by a thick solid line in FIG. 3), and the high frequency units 3b and 3c and The other components are always supplied directly (not shown). The SW unit 8b includes a first SW 81b that turns on / off the power supply from the power supply unit 7 to the signal processing unit 5c, a second SW 82b that turns on / off the power supply from the power supply unit 7 to the signal processing unit 5b, and the power supply unit 7 To the high frequency unit 3a and the third SW 83b for turning on / off the power supply to the signal processing unit 5a. The output on the receiving side from the high frequency unit 3b to the signal processing unit 5b (that is, the output from the DEM 36b to the ADC 52b) and the output on the receiving side from the high frequency unit 3c to the signal processing unit 5c (that is, the output from the DEM 36c to the ADC 52c) The signal level detection circuit 6b is connected. The signal level detection circuit 6b receives the reception level from the high frequency unit 3b to the signal processing unit 5b (that is, the level of the baseband signal in the second frequency band) and the reception level from the high frequency unit 3c to the signal processing unit 5c (that is, The level of the baseband signal in the third frequency band) is detected, and the operations of the first to third SWs 81b to 83b of the SW unit 8b are controlled based on the detection results. Hereinafter, the operation of supplying power in the communication device 1b will be described with reference to FIG. FIG. 4 is a flowchart showing the operation of the communication device 1b.

  In FIG. 4, the signal level detection circuit 6b detects the reception level (that is, the level of the baseband signal in the second and third frequency bands) received by the high frequency units 3b and 3c, respectively (step S21). Since the signal level detection circuit 6b and the high-frequency units 3b and 3c are always directly supplied with power from the power supply unit 7 as described above, the signal level detection circuit 6b always receives the respective reception levels. Can be monitored.

  Next, the signal level detection circuit 6b turns ON the second SW 82b of the SW unit 8b when the reception level received by the high frequency unit 3b detected in step S21 is equal to or higher than a predetermined threshold (step S22). As a result, power is supplied from the power supply unit 7 to the signal processing unit 5b (step S23). Then, the signal level detection circuit 6b turns off the first and third SWs 81b and 83b of the SW unit 8b. As a result, power supply from the power supply unit 7 to the high frequency unit 3a and the signal processing units 5a and 5c is stopped (step S24). And the 2nd transmission / reception part (namely, high frequency part 3b and signal processing part 5b) of the communication apparatus 1b performs transmission / reception of the signal using a 2nd frequency band (step S25). Next, when communication is continued (step S33), the communication device 1b returns to step S21 and repeats the operation. When communication is terminated (step S33), the operation according to the flowchart ends.

  On the other hand, in the signal level detection circuit 6b, the reception level received by the high frequency unit 3b detected in step S21 is less than a predetermined threshold (step S22), and the reception level received by the high frequency unit 3c is greater than or equal to the predetermined threshold. In the case (step S26), the third SW 83b of the SW unit 8b is turned on. As a result, power is supplied from the power supply unit 7 to the signal processing unit 5c (step S27). Then, the signal level detection circuit 6b turns off the first and second SWs 81b and 82b of the SW unit 8b. As a result, power supply from the power supply unit 7 to the high frequency unit 3a and the signal processing units 5a and 5b is stopped (step S28). And the 3rd transmission / reception part (namely, high frequency part 3c and signal processing part 5c) of the communication apparatus 1b performs transmission / reception of the signal using a 3rd frequency band (step S29). Next, when communication is continued (step S33), the communication device 1b returns to step S21 and repeats the operation. When communication is terminated (step S33), the operation according to the flowchart ends.

  Further, the signal level detection circuit 6b has the reception level received by the high frequency unit 3b detected in step S21 above the predetermined threshold (step S22), and the reception level received by the high frequency unit 3c is below the predetermined threshold. In the case (step S26), the first SW 81b of the SW unit 8b is turned on. As a result, power is supplied from the power supply unit 7 to the high frequency unit 3a and the signal processing unit 5a (step S30). Then, the signal level detection circuit 6b turns off the second and third SWs 82b and 83b of the SW unit 8b. As a result, power supply from the power supply unit 7 to the signal processing units 5b and 5c is stopped (step S31). And the 1st transmission / reception part (namely, high frequency part 3a and signal processing part 5a) of the communication apparatus 1b performs transmission / reception of the signal using a 1st frequency band (step S32). Next, when communication is continued (step S33), the communication device 1b returns to step S21 and repeats the operation. When communication is terminated (step S33), the operation according to the flowchart ends.

  Thus, in the communication device 1b, when a signal using the second frequency band is receivable in a multimode terminal that transmits and receives signals using three different frequency bands, the second frequency band is used. Thus, low power consumption is realized by stopping the supply of power to the first transmission / reception unit (high-frequency unit 3a and signal processing unit 5a) and the signal processing unit 5c of the third transmission / reception unit. Further, in the communication device 1b, when a signal using the second frequency band cannot be received and a signal using the third frequency band can be received, transmission / reception of the signal using the third frequency band is performed. The power supply to the signal processing unit 5b of the first transmission / reception unit and the second transmission / reception unit is stopped to achieve low power consumption. Further, in the communication device 1b, when both signals using the second and third frequency bands cannot be received, signals are transmitted and received using the first frequency band, and the second and third transmitting / receiving units The power supply to the signal processing units 5b and 5c is stopped to realize low power consumption. That is, the communication device 1b also realizes low power consumption by stopping power supply to unnecessary transmission / reception units according to the reception state. The communication device 1b prioritizes transmission / reception with respect to three different frequency bands, and transmits / receives data from those that can be received in the order of the second frequency band → the third frequency band → the first frequency band. Control is possible, and low power consumption is realized according to the reception state. For example, the first frequency band is a frequency band used for mobile phone terminals (800 MHz band) and a frequency band used for PHS (1.9 GHz band), and the second frequency band is a frequency band used for wireless LAN (2.4 GHz). The third frequency band is a frequency band (5.2 GHz band) used in the wireless LAN. That is, there are generally few areas (wireless LAN service areas) where signals using the second and third frequency bands can be transmitted and received, and prioritization is performed for these signals. Then, as much as possible, signals using the second frequency band are transmitted / received with the highest priority, and then signals using the third frequency band are transmitted / received with priority, to an unnecessary transmitting / receiving unit. When the signal supply using the second and third frequency bands cannot be received, the first frequency band (mobile phone or PHS service area) is relatively wide. This is an example in which the data communication is performed using and the power supply of unnecessary signal processing units is stopped.

  Note that the communication device 1b may receive or transmit a signal using the first frequency band under a predetermined condition, even if the signal using the second or third frequency band can be received. For example, when control by the CPU 10 is added to the signal level detection circuit 6b and a signal is currently transmitted and received using the first frequency band (that is, the high frequency unit 3a and the signal processing unit 5a are used) The third SW 83b of the SW unit 8b may be turned on only during the period in use. Thereby, low power consumption can be realized without interrupting transmission and reception of signals using the first frequency band.

  In the second embodiment, a method of switching between three different frequency bands to be transmitted / received has been described. Even when there are four or more usable frequency bands, the same is achieved by setting the priority for transmitting / receiving each frequency band. Needless to say, the present invention can be realized.

  In the communication apparatuses 1a and 1b described in the first and second embodiments, the first to third frequency bands to be transmitted / received have been described as examples. However, the frequency bands to be transmitted / received are not limited thereto. Needless to say, the method of allocating the frequency band described above to the first to third frequency bands is not limited to the above-described example.

  The communication device and the communication method according to the present invention achieve low power consumption and are useful when transmitting / receiving signals using a plurality of different frequency bands.

The block diagram which shows the structure of the communication apparatus which concerns on the 1st Embodiment of this invention. The flowchart which shows operation | movement of the communication apparatus 1a of FIG. The block diagram which shows the structure of the communication apparatus which concerns on the 2nd Embodiment of this invention. The flowchart which shows operation | movement of the communication apparatus 1b of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Communication apparatus 2 ... Antenna 3 ... High frequency part 31 ... Transmission / reception switching SW
32 ... LNA
33, 35, 43 ... Filters 34, 44 ... Mixer 36 ... DEM
41 ... Power amplifier 42 ... Preamplifier 45 ... MOD
5 ... Signal processor 51 ... DAC
52 ... ADC
53 ... Signal processing circuit 6 ... Signal level detection circuit 7 ... Power supply unit 8 ... SW unit 81 ... First SW
82 ... 2nd SW
83 ... 3rd SW
10 ... CPU

Claims (10)

A communication device that transmits and receives signals using a plurality of different frequency bands,
A first high-frequency unit that transmits and receives signals using the first frequency band;
A first signal processing unit that performs predetermined signal processing on a signal transmitted and received by the first high-frequency unit;
A second high-frequency unit that transmits and receives a signal using a second frequency band different from the first frequency band;
A second signal processing unit that performs predetermined signal processing on a signal transmitted and received by the second high-frequency unit;
A power supply unit that supplies power to at least the first and second high-frequency units and the first and second signal processing units;
A switch unit for connecting / disconnecting a power supply line from the power supply unit to the first high-frequency unit and the first and second signal processing units,
A signal level detection unit that controls connection / disconnection operation of the switch unit according to a first reception level of a signal using the second frequency band received by the second high-frequency unit;
The signal level detector is
When the first reception level is greater than or equal to a predetermined value, the power supply line from the power supply unit to the first high-frequency unit and the first signal processing unit in the switch unit is disconnected and the first power level from the power supply unit to the first 2 connecting the power supply line to the signal processing unit,
When the first reception level is less than a predetermined value, the power supply line from the power supply unit to the second signal processing unit in the switch unit is disconnected, and the first high-frequency unit and the first power supply unit are disconnected from the power supply unit. A communication apparatus, comprising: a power supply line connected to one signal processing unit.   The signal level detection unit is configured such that when the first reception level is equal to or higher than a predetermined value and the first high-frequency unit and the first signal processing unit are performing signal transmission / reception processing, the transmission / reception processing ends. Disconnecting a power supply line from the power supply unit to the first high-frequency unit and the first signal processing unit in the switch unit, and connecting a power supply line from the power supply unit to the second signal processing unit. The communication device according to claim 1, wherein:   2. The communication according to claim 1, wherein an area where the signal using the second frequency band can be received is relatively narrower than an area where the signal using the first frequency band can be received. apparatus. A third high-frequency unit that transmits and receives a signal using a third frequency band different from the first and second frequency bands;
A third signal processing unit that performs predetermined signal processing on a signal transmitted and received by the third high-frequency unit;
The power supply unit further supplies power to the third high-frequency unit and the third signal processing unit,
The switch unit further connects / disconnects a power supply line from the power supply unit to the third signal processing unit,
The signal level detector is
Further, according to the second reception level of the signal using the third frequency band received by the third high frequency unit, the connection / disconnection operation of the switch unit is controlled,
When the first reception level is equal to or higher than a predetermined value, the power supply line from the power supply unit to the first high-frequency unit and the first and third signal processing units in the switch unit is disconnected and the power supply Connecting a power supply line from the unit to the second signal processing unit,
When the first reception level is less than a predetermined value and the second reception level is greater than or equal to a predetermined value, the first high frequency unit and the first and second signal processing from the power supply unit in the switch unit A power supply line from the power supply unit to the second signal processing unit by cutting the power supply line to the unit,
When both of the first and second reception levels are less than a predetermined value, the power supply line from the power supply unit to the second and third signal processing units in the switch unit is disconnected to disconnect the power supply unit from the power supply unit. The communication apparatus according to claim 1, wherein a power supply line to one high-frequency unit and the first signal processing unit is connected.   The signal level detection unit performs the transmission / reception processing when the first or second reception level is equal to or higher than a predetermined value and the first high frequency unit and the first signal processing unit are transmitting / receiving signals. After completion, the power supply line from the power supply unit to the first high-frequency unit and the first signal processing unit in the switch unit is disconnected, and the power supply unit to the second or third signal processing unit The communication apparatus according to claim 4, wherein a power supply line is connected.   The area where signals using the second and third frequency bands can be received is relatively narrower than the area where signals using the first frequency band can be received. The communication device described. A communication method for transmitting and receiving signals using a plurality of different frequency bands,
A signal using at least the first frequency band and a signal using a second frequency band different from the first frequency band can be transmitted and received,
When the first reception level of the received signal using the second frequency band is equal to or higher than a predetermined value, the first high-frequency unit that transmits and receives the signal using the first frequency band and the signal processing the signal The power supply to the first signal processing unit is stopped, and the power is supplied to the second high-frequency unit that transmits and receives signals using the second frequency band and the second signal processing unit that processes the signals And
When the first reception level is less than a predetermined value, power supply to the second signal processing unit is stopped, and power is supplied to the first and second high frequency units and the first signal processing unit. A communication method comprising: supplying a communication method.   When the first reception level is equal to or higher than a predetermined value and a signal using the first frequency band is being transmitted / received, the first high-frequency unit and the first signal processing are performed after the transmission / reception processing ends. The communication method according to claim 7, wherein power supply to the unit is stopped and power is supplied to the second signal processing unit. Furthermore, a signal using a third frequency band different from the first and second frequency bands can be transmitted and received,
Third signal processing for performing signal processing on a signal using the third frequency band transmitted and received between the first high frequency unit and the first signal processing unit when the first reception level is equal to or higher than a predetermined value. To supply power to the second high-frequency unit, the second signal processing unit, and a third high-frequency unit that transmits and receives signals using the third frequency band,
When the first reception level is less than a predetermined value and the second reception level of the received signal using the third frequency band is greater than or equal to a predetermined value, the first high-frequency unit and the first and Stopping power supply to the second signal processing unit and supplying power to the second and third high-frequency units and the third signal processing unit;
When both of the first and second reception levels are less than a predetermined value, power supply to the second and third signal processing units is stopped, and the first to third high-frequency units and the first The communication method according to claim 7, wherein power is supplied to the signal processing unit.   When the first or second reception level is equal to or higher than a predetermined value and a signal using the first frequency band is being transmitted / received, the first high-frequency unit and the first The communication method according to claim 9, wherein power supply to the signal processing unit is stopped and power is supplied to the second or third signal processing unit.

Images