JP2013197865A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress power consumption of a communication device even under a bad communication state.SOLUTION: The communication device 1 includes: a radio communication circuit 2 that transmits and receives a radio signal; a power supply 6 that supplies electric power to the radio communication circuit 2; a reception strength measurement circuit 42 that measures the reception strength of a radi signal under a condition where no electric power is supplied to the radio communication circuit 2; and a power supply control circuit 45 that turns on power supply from the power supply 6 to the radio communication circuit 2 when the reception strength measured by the reception strength measurement circuit 42 exceeds a threshold value.

Description

  Embodiments discussed herein relate to power savings in communication devices.

  CDMA (Code Division Multiple Access) mobile phones that check the rate of decrease in received electric field strength within a predetermined time when transitioning from a service area to a service area when transitioning from a service area to a service area is known. Yes. If the rate of decrease in the received electric field strength is rapid, the CDMA mobile phone determines that the cell moves from a zone without cell movement to the outside of the zone, and stops the cell search during the out-of-zone period.

  In addition, the mobile unit includes a receiving unit that receives a radio signal from the base station, and an intermittent reception power setting unit that opens and closes the power of the receiving unit in synchronization with a specific time slot from the signal received by the receiving unit. A receiving device for communication is known. The receiving apparatus includes means for detecting the reception level of the received signal and a control unit that stops the power supply for a first time when the reception level detected by the detecting means is equal to or lower than a predetermined value.

JP 2001-285178 A JP-A-6-53881

  The communication device stops the cell search during the out-of-service period when there is no cell movement when the rate of decrease in the received electric field strength is abrupt, but continues the cell search while the received signal strength is weak and the communication state is poor, Consume power. For this reason, if the state in which the battery of the communication device does not remain charged continues even if the communication state is recovered, the communication device may not be used because the battery runs out. For example, a mobile station apparatus in a mobile communication system consumes a certain amount of power because it performs a process such as cell search even during a period when the communication state with the base station apparatus is poor.

  It is an object of the disclosed apparatus and method to reduce power consumption of a communication apparatus during a period in which a communication state is bad.

  According to one aspect of the apparatus, a wireless communication circuit that transmits and receives wireless signals, a power source that supplies power to the wireless communication circuit, and reception that measures the reception strength of the wireless signal in a state where no power is supplied to the wireless communication circuit A communication device is provided that includes an intensity measurement circuit and a power supply control circuit that turns on power supply from the power supply to the wireless communication circuit when the reception intensity measured by the reception intensity measurement circuit exceeds a threshold value.

  According to the device or method of the present disclosure, it is possible to reduce the power consumption of the communication device during a period in which the communication state is bad.

It is a hardware block diagram of the communication apparatus of 1st Example. FIG. 2 is an explanatory diagram of an operation of turning off power supply to the wireless communication circuit of FIG. 1. It is explanatory drawing of the operation | movement which turns ON the power supply to the radio | wireless communication circuit of FIG. It is a hardware block diagram of the communication apparatus of 2nd Example. It is a hardware block diagram of the communication apparatus of 3rd Example.

<1. First Example>
<1.1. Hardware configuration of communication device>
Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIG. 1 is a hardware configuration diagram of the communication apparatus according to the first embodiment. The hardware configuration illustrated in FIG. 1 is an example of a hardware configuration that implements a communication device. Any other hardware configuration may be adopted as long as the operation described below is performed in this specification. In FIG. 1, switches, antenna duplexers, analog-digital converters, field programmable gate arrays, digital-analog converters, and bandpass filters are represented by “SW”, “DUP”, “ADC”, “FPGA”, “DAC”, and Indicated as “BPF”. The same applies to FIG. 4 showing a second example of the hardware configuration.

  The communication device 1 includes a wireless communication circuit 2, a monitoring circuit 3, and antennas 4 and 5. The communication device 1 also includes a first battery 6 that supplies power to the wireless communication circuit 2, and a first switch 7 that turns on and off power supply from the first battery 6 to the wireless communication circuit 2. In addition, the communication device 1 includes a second battery 8 that supplies power to the monitoring circuit 3 and a second switch 9 that turns on and off power supply from the second battery 8 to the monitoring circuit 3.

  The wireless communication circuit 2 includes an antenna duplexer 11, a first wireless signal receiving circuit 12, an analog-digital converter 13, and an FPGA (Field-Programmable Gate Array) 14. The wireless communication circuit 2 includes a digital-analog converter 15, a wireless signal transmission circuit 16, a microphone 17, a speaker 18, a codec circuit 19, an input device 20, a display device 21, and a memory 22.

  The radio signal received by the antenna 4 is band-filtered by the antenna duplexer 11 and then input to the first radio signal receiving circuit 12. The first radio signal receiving circuit 12 amplifies the received signal, which is a radio frequency signal, and converts it to an intermediate frequency signal. The analog-to-digital converter 13 converts the received signal having the intermediate frequency into a digital signal and inputs the digital signal to the FPGA 14.

  The FPGA 14 performs baseband processing of signals transmitted and received by the wireless communication circuit 2 through wireless communication. For example, the FPGA 14 performs a modulation / demodulation process, an encoding process, a decoding process, and a protocol process on a wireless signal transmitted and received by the wireless communication circuit 2. When the communication device 1 is a mobile station terminal device used in a mobile communication system, the FPGA 14 performs a cell search process. For example, in the case of a mobile station terminal device in W-CDMA (Wideband Code Division Multiple Access) format, the cell search process includes detection of frame timing and identification of the scrambling code of the base station device. In the case of an LTE (Long Term Evolution) type mobile station terminal device, the cell search process includes detection of frame timing and identification of a cell ID.

  Further, the FPGA 14 measures the received signal strength indication (RSSI) of the received signal received by the communication apparatus 1. For this reason, the FPGA 14 includes a first RSSI measurement circuit 31. The first RSSI measurement circuit 31 measures the RSSI of the received signal received by the antenna 4. The first RSSI measurement circuit 31 stores the RSSI measurement value in the memory 22.

  The FPGA 14 displays the RSSI measurement result by the first RSSI measurement circuit 31 on the display device 21. Further, the FPGA 14 calculates an index such as reception quality used for baseband processing of wireless communication based on the RSSI measurement result by the first RSSI measurement circuit 31.

  Further, the FPGA 14 controls the first switch 7 to turn off the power supply from the first battery 6 to the wireless communication circuit 2 when the reception intensity of the reception signal is sharply reduced. For this reason, the FPGA 14 includes a first determination circuit 32 and a first power supply control circuit 33.

  The first determination circuit 32 determines whether or not the measurement value increases after the RSSI measurement value rapidly decreases. For example, the first determination circuit 32 determines that the RSSI has sharply decreased when a decrease in a plurality of RSSIs measured at a predetermined interval exceeds a threshold value.

  If the measured value of RSSI does not increase while rapidly decreasing, it is considered that the transmitting apparatus, for example, the base station apparatus has stopped. On the other hand, the RSSI gradually decreases when the communication device 1 moves behind the building or when the RSSI decreases due to radio wave interference from other transmission devices. Therefore, the first determination circuit 32 can distinguish between a decrease in RSSI in such a case and a case in which the transmission apparatus is stopped. The first power supply control circuit 33 controls the first switch 7 to turn off the power supply from the first battery 6 to the wireless communication circuit 2 when the measured value of RSSI does not rise while rapidly decreasing.

  The communication device 1 according to another embodiment includes a DSP (Digital Signal Processor) that performs the above-described processing by the FPGA 14 and a memory that stores a program executed by the DSP, instead of or in addition to the FPGA 14. It's okay. Further, the communication device 1 of another embodiment may include a logic circuit such as an LSI (large scale integration) or an ASIC (Application Specific Integrated Circuit) that performs the above-described processing by the FPGA 14 instead of or in addition to the FPGA 14. Good.

  The digital-analog converter 15 converts the digital transmission signal output from the FPGA 14 into an analog signal. The radio signal transmission circuit 16 converts an analog transmission signal into a radio frequency signal, and then amplifies and outputs the signal. A transmission signal output from the wireless signal transmission circuit 16 is transmitted from the communication device 1 via the antenna duplexer 11 and the antenna 4.

  The microphone 17 receives a voice input from the user to the communication device 1. The speaker 18 outputs sound. The codec circuit 19 converts the analog audio signal detected by the microphone 17 into a digital signal and inputs the digital signal to the FPGA 14. The codec circuit 19 converts the digital audio signal output from the FPGA 14 into an analog signal and outputs the analog signal to the speaker 18.

  The input device 20 and the display device 21 are user interface devices for accepting user input operations on the communication device 1. The input device 20 includes, for example, a numeric keypad for inputting a telephone number, a cursor key, and a dedicated key for a specific operation. The input device 20 may include a touch panel. The display device 21 displays information transmitted / received by the communication apparatus 1 and user operation details on the input device 20. The display device 21 may be, for example, a liquid crystal display device, an organic light emitting diode, or a field emission display.

  The monitoring circuit 3 monitors the received signal strength of the communication device 1 and turns the power supply from the first battery 6 to the wireless communication circuit 2 from OFF to ON when the received signal strength exceeds a threshold value. As a result, power supply to the wireless communication circuit 2 stopped due to the decrease in RSSI is resumed. The monitoring circuit 3 includes a bandpass filter 41, a second radio signal receiving circuit 42, a second RSSI measurement circuit 43, a second determination circuit 44, and a second power supply control circuit 45.

  The radio signal received by the antenna 5 is band-filtered by the bandpass filter 41 and then input to the second radio signal receiving circuit 42. The second radio signal receiving circuit 42 amplifies the received signal, which is a radio frequency signal, and converts it to an intermediate frequency signal. The intermediate frequency reception signal output from the second radio signal reception circuit 42 is input to the second RSSI measurement circuit 43.

  The second RSSI measurement circuit 43 measures the RSSI of the received signal received by the antenna 5. The second determination circuit 44 determines whether or not the RSSI measured by the second RSSI measurement circuit 43 exceeds a predetermined threshold value. When the RSSI exceeds a predetermined threshold, the second power supply control circuit 45 turns the power supply from the first battery 6 to the wireless communication circuit 2 from OFF to ON.

  The second RSSI measurement circuit 43 includes an analog conversion circuit that generates a voltage signal indicating the received intensity from the received signal. Such an analog conversion circuit may be, for example, a rectifier circuit that generates an envelope signal of a reception signal having an intermediate frequency. The second determination circuit 44 may be, for example, an analog comparator that compares the voltage signal intensity output from the second RSSI measurement circuit 43 with a predetermined reference voltage. The second power supply control circuit 45 may be, for example, an amplifier circuit that generates a drive signal for the first switch 7 in accordance with the comparison result signal from the second determination circuit 44. Such a monitoring circuit 3 can be a circuit with lower power consumption than the wireless communication circuit 2.

<1.2. Power control operation of wireless communication circuit>
FIG. 2 is an explanatory diagram of an operation of turning off the power supply to the wireless communication circuit 2 of FIG. Hereinafter, a series of operations described with reference to FIG. 2 may be interpreted as a method including a plurality of procedures. In this case, “operation” may be read as “step”. The same applies to the case of FIG.

  In operation AA, the first RSSI measurement circuit 31 measures the RSSI of the received signal received by the antenna 4. In operation AB, the first RSSI measurement circuit 31 stores the measurement value R1 obtained in operation AA in the memory 22. In operation AC, the first RSSI measurement circuit 31 measures the RSSI of the received signal received by the antenna 4. In operation AD, the first RSSI measurement circuit 31 stores the measurement value R2 obtained in operation AC in the memory 22.

  In operation AE, the first determination circuit 32 determines whether or not the RSSI measurement value R2 has rapidly decreased from the measurement value R1. If the measured value R2 has fallen sharply from the measured value R1 (operation AE: Y), the processing proceeds to operation AF. If the measured value R2 does not drop rapidly from the measured value R1 (operation AE: N), the processing returns to operation AA.

  Thereafter, in operation AF after a certain period of time has elapsed, the first RSSI measurement circuit 31 measures the RSSI of the received signal received by the antenna 4. In operation AG, the first RSSI measurement circuit 31 stores the measurement value R3 obtained in operation AF in the memory 22. In operation AH, the first determination circuit 32 determines whether or not the RSSI measurement value R3 has increased from the measurement value R2. When the measured value R3 has changed from the measured value R2 (operation AH: Y), the processing returns to operation AA.

  If the measured value R3 does not change from the measured value R2 (operation AH: N), that is, if the measured value of RSSI does not increase while decreasing, the process proceeds to operation AI. In operation AI, the first power supply control circuit 33 controls the first switch 7 to turn off the power supply from the first battery 6 to the wireless communication circuit 2. Thereafter, the process ends.

  In another embodiment, in operation AH, the first determination circuit 32 may determine whether or not the difference between the RSSI measurement value R3 and the measurement value R1 is within a certain range. When the difference between the measurement value R3 and the measurement value R1 is not within a certain range, the first power supply control circuit 33 may turn off the power supply to the wireless communication circuit 2.

  FIG. 3 is an explanatory diagram of an operation of turning on the power supply to the wireless communication circuit 2 of FIG. For example, when the communication apparatus 1 is a mobile station apparatus, when the base station apparatus is restored or when the communication apparatus 1 moves into a cell of another base station apparatus, the power supply to the wireless communication circuit 2 is performed by this operation. Turn on the supply. In operation BA, the second RSSI measurement circuit 43 measures the RSSI of the received signal received by the antenna 5. In operation BB, the second determination circuit 44 determines whether or not the measurement value obtained in operation BA exceeds a predetermined threshold value.

  When the measured value exceeds the predetermined threshold (operation BB: Y), the process proceeds to operation BC. If the measured value does not exceed the predetermined threshold (operation BB: N), the processing returns to operation BA. In operation BC, the second power supply control circuit 45 turns the power supply from the first battery 6 to the wireless communication circuit 2 from OFF to ON.

<1.3. Effect>
According to the present embodiment, it is possible to turn off the power supply to other parts of the circuit while leaving the monitoring circuit 3 for monitoring the received signal strength during a period in which the received signal strength is small and the communication state is poor. As described above, since the monitoring circuit 3 can be a circuit that consumes less power than the other circuits of the communication device 1, the power consumption of the communication device 1 can be reduced. Then, immediately after the communication state is recovered, the power supply in the communication device 1 can be resumed to make the communication device 1 usable.

  For example, in the case of a mobile station apparatus, it is possible to prevent power consumption due to cell search processing repeated during a period in which the communication state is bad. Further, for example, power consumption due to standby power of a radio signal transmission amplifier can be prevented.

  In this embodiment, the monitoring circuit 3 that is driven during a period in which the communication state is bad is a circuit different from the FPGA 14 that performs baseband processing of transmission / reception signals. As a result, it is easy to separate the power supply to the FPGA 14 and the power supply to the monitoring circuit 3, and the circuit configuration for turning off the FPGA 14 while the monitoring circuit 3 is ON is simplified.

  The second power supply control circuit 45 controls the second switch 9 to supply power from the second battery 8 to the monitoring circuit 3 when turning on the power supply from the first battery 6 to the wireless communication circuit 2. You may turn it off. When the power supply from the first battery 6 to the wireless communication circuit 2 is turned off, the first power supply control circuit 33 controls the second switch 9 to supply power from the second battery 8 to the monitoring circuit 3. You can turn it on. Thus, the power consumption of the communication device 1 can be further reduced by turning off the power supply to the monitoring circuit 3 during the period when the power supply to the wireless communication circuit 2 is ON.

<2. Second Embodiment>
FIG. 4 is a hardware configuration diagram of the communication device 1 according to the second embodiment. The same components as those shown in FIG. 1 are denoted by the same reference numerals. In the communication device 1 of the present embodiment, the wireless communication circuit 2 and the monitoring circuit 3 share the antenna 4 and the antenna duplexer 11. For this reason, an antenna and a band pass filter dedicated to the monitoring circuit 3 are not required, and the circuit can be reduced in size.

  Further, according to the present embodiment, when the monitoring circuit 3 determines whether the wireless communication circuit 2 can be turned on based on the received signal strength, the signal received by the antenna 4 used in the wireless communication circuit 2 is used as a reference. For this reason, the sensitivity adjustment resulting from the difference in the antenna sensitivity which arises when the antenna of the monitoring circuit 3 and the antenna of the radio | wireless communication circuit 2 are provided separately becomes unnecessary.

  In another embodiment, when the RSSI measured by the second RSSI measurement circuit 43 suddenly decreases, the second power supply control circuit 45 controls the first switch 7 to transfer from the first battery 6 to the wireless communication circuit 2. The power supply may be turned off. In this case, the first determination circuit 32 and the first power supply control circuit may be omitted. In still another embodiment, the wireless communication circuit 2 and the monitoring circuit 3 may share the same battery.

<3. Third Example>
FIG. 5 is a hardware configuration diagram of the communication device 1 according to the third embodiment. The same components as those shown in FIG. 1 are denoted by the same reference numerals. The communication device 1 according to the present embodiment is a mobile station device in a mobile communication system, and stops random access when the reception strength of a received signal rapidly decreases. The FPGA 14 includes a RACH (Random Access Channel) control circuit 34.

  The RACH control circuit 34 stops random access to the base station apparatus by the communication apparatus 1 when the measured value of RSSI does not rise while rapidly decreasing. While the random access is stopped, the first determination circuit 32 determines whether the RSSI measured by the first RSSI measurement circuit 31 exceeds a predetermined threshold. When the RSSI exceeds a predetermined threshold, the RACH control circuit 34 resumes random access to the base station device by the communication device 1.

  According to the present embodiment, the random access to the base station apparatus by the communication apparatus 1 can be stopped during a period when the received signal strength is small and the communication state is bad. For this reason, it is possible to prevent the communication device 1 from consuming power due to transmission of the random access preamble during a period in which the communication state is poor. For example, by transmitting the random access preamble while the base station apparatus is stopped, it is possible to prevent the communication apparatus 1 from consuming power wastefully.

<4. Other Examples>
When the communication apparatus 1 is a mobile station apparatus in a mobile communication system, the base station apparatus transmits a control signal indicating that the base station apparatus is operating. For example, the base station apparatus may include such a control signal in the broadcast information, and the base station apparatus may transmit a beacon indicating that the base station apparatus is operating.

  The first determination circuit 32 and the second determination circuit 44 may determine whether or not the base station apparatus is operating according to this control signal. The first power supply control circuit 33 and the second power supply control circuit 45 turn on the power supply from the first battery 6 to the wireless communication circuit 2 when the base station apparatus is in operation, and the base station apparatus is not in operation. In addition, the power supply from the first battery 6 to the wireless communication circuit 2 is turned off.

  The base station apparatus may transmit a control signal indicating the power state. For example, the control signal notifies the communication device 1 that the remaining capacity of the built-in battery of the base station device is below a predetermined allowable value. The first determination circuit 32 determines whether or not the remaining capacity of the built-in battery of the base station apparatus is below a predetermined allowable value in accordance with this notification. The first power supply control circuit 33 turns off the power supply from the first battery 6 to the wireless communication circuit 2 when the remaining capacity of the built-in battery of the base station apparatus falls below a predetermined allowable value.

The following additional notes are further disclosed with respect to the embodiment including the above examples.
(Appendix 1)
A wireless communication circuit for transmitting and receiving wireless signals;
A power supply for supplying power to the wireless communication circuit;
A reception strength measurement circuit for measuring the reception strength of a radio signal in a state where power is not supplied to the radio communication circuit;
A power supply control circuit that turns on power supply from the power supply to the wireless communication circuit when the reception intensity measured by the reception intensity measurement circuit exceeds a threshold; and
A communication apparatus comprising:
(Appendix 2)
The communication apparatus according to appendix 1, wherein the reception intensity measurement circuit is a circuit that consumes less power than the wireless communication circuit.
(Appendix 3)
The wireless communication circuit includes a digital logic circuit that performs baseband processing of transmission and reception signals,
The communication apparatus according to appendix 2, wherein the reception intensity measurement circuit includes an analog conversion circuit that generates a received signal from a voltage signal indicating the reception intensity.
(Appendix 4)
The wireless communication circuit, a first reception strength measurement circuit for measuring the reception strength,
A second power supply control circuit for turning off the power supply from the power supply to the wireless communication circuit when the reception strength measured by the first reception strength measurement circuit sharply decreases;
The communication apparatus according to any one of appendices 1 to 3, further comprising:
(Appendix 5)
The communication apparatus according to appendix 4, wherein the first power supply control circuit turns off the power supply to the reception strength measurement circuit when turning off the power supply to the wireless communication circuit. .
(Appendix 6)
The communication apparatus according to any one of appendices 1 to 5, wherein the reception intensity measurement circuit receives a radio signal via an antenna and an antenna duplexer for the radio communication circuit to transmit and receive a radio frequency signal.

DESCRIPTION OF SYMBOLS 1 Communication apparatus 2 Wireless communication circuit 3 Monitoring circuit 6 1st battery 7 1st switch 31 1st RSSI measurement circuit 32 1st determination circuit 33 1st power supply control circuit 43 2nd RSSI measurement circuit 44 2nd determination circuit 45 2nd power supply control circuit

Claims (5)

A wireless communication circuit for transmitting and receiving wireless signals;
A power supply for supplying power to the wireless communication circuit;
A reception strength measurement circuit for measuring the reception strength of a radio signal in a state where power is not supplied to the radio communication circuit;
A power supply control circuit that turns on power supply from the power supply to the wireless communication circuit when the reception intensity measured by the reception intensity measurement circuit exceeds a threshold; and
A communication apparatus comprising:   The communication apparatus according to claim 1, wherein the reception intensity measurement circuit is a circuit that consumes less power than the wireless communication circuit. The wireless communication circuit includes a second reception intensity measurement circuit that measures reception intensity;
A second power supply control circuit for turning off power supply from the power supply to the wireless communication circuit when the reception intensity measured by the second reception intensity measurement circuit suddenly decreases;
The communication apparatus according to claim 1, further comprising:   4. The communication according to claim 3, wherein when the power supply to the wireless communication circuit is turned off, the second power supply control circuit turns the power supply to the reception intensity measurement circuit from off to on. 5. apparatus.   The communication apparatus according to claim 1, wherein the reception intensity measurement circuit receives a radio signal via an antenna and an antenna duplexer for the radio communication circuit to transmit and receive a radio frequency signal.

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