JP2006246172A - Radio communications equipment and transmission/reception control method therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio communications equipment for optimally setting diversity transmitting/receiving performance by a plurality of antennas according to the lifetime of a battery and a transmission/reception control method in the radio communications equipment. <P>SOLUTION: In a normal mode, a radio communication 10 performs reception by composite diversity by the plurality of antennas of an antenna 11. Then, a residual amount of the battery is detected; and when it is lower than the predetermined threshold, the radio communication 10 is put in a low power consumption mode. In the low power consumption mode, power supplying to the partial radio transmitter/receiver of a front end 13 is stopped, a battery lifetime is extended, an antenna, corresponding to the radio transmitter/receiver whose power supply has been stopped, is used for selective diversity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication device such as a portable terminal device that operates on a battery and performs communication using a plurality of antennas, and a transmission / reception control method in the wireless communication device.

A wireless communication device typified by a cellular phone is mainly used by battery driving. Accordingly, various technologies have been developed for low power consumption so that the battery can be used as long as possible by one charge.
For example, Patent Document 1 below discloses a communication terminal that suppresses power consumption by detecting the presence / absence of transmission data and controlling the presence / absence of operation of the communication function according to the detection result. Patent Document 2 below detects that the electric field strength of radio waves received from the base station has decreased as a result of being away from the base station, and stops responding to location registration requests from the base station or reduces the number of responses. A mobile terminal that reduces power consumption by switching to an operation mode is disclosed.

JP 2004-164666 A JP 2003-258705 A

  By the way, in IEEE802.11n, which is being studied as a standard for next-generation wireless LAN, as a technology for speeding up a wireless LAN, a MIMO (Multi-Multi) that multiplexes a plurality of signals with a plurality of transmission antennas and further receives them with a plurality of reception antennas. Input Multi-Output) technology is being studied. Such MIMO technology is premised on diversity transmission / reception operations using a plurality of antennas. As described above, when a plurality of antennas and a plurality of corresponding front ends (input / output signal processing units) are mounted, the power consumption becomes high, and thus low power consumption is particularly demanded.

  On the other hand, depending on the wireless communication device, there is an application in which power consumption is given priority over communication performance and it is desired to extend the life of the battery as much as possible even if the communication performance slightly deteriorates.

  Accordingly, an object of the present invention is to provide a wireless communication apparatus capable of optimally setting diversity transmission / reception performance by a plurality of antennas according to the life of a battery, and a transmission / reception control method in the wireless communication apparatus.

In order to overcome the above-described problems, a first aspect of the present invention is a wireless communication device that is operated by a battery, and includes a plurality of antennas and a plurality of input / output signal processing units connected corresponding to each antenna. The remaining amount detecting means for detecting the remaining amount of the battery, the detected value by the remaining amount detecting means and a predetermined threshold value are compared, and if the detected value falls below the predetermined threshold value, the plurality of inputs The power supply stopping means for stopping the power supply to a part of the output signal processing unit and the first antenna corresponding to the first input / output signal processing unit that is the target of the power supply stop are selected for the purpose of diversity. And a connection switching means for selectively connecting to the second input / output signal processing section.
Here, “remaining battery capacity” is a general concept for the remaining battery life, and is indirectly replaced with other physical quantities such as the time since the start of use and the fluctuation value of the voltage level of the battery. Also included.

  Preferably, the baseband processing unit is connected to the plurality of input / output signal processing units and processes a baseband signal, and the baseband processing unit has a detection value by the remaining amount detection means that has the predetermined threshold value. The baseband signal is processed with the combined diversity of the plurality of antennas on the condition that it exceeds the maximum.

  Preferably, the power supply stopping unit compares the detected value with a plurality of threshold values, and stops power supply to the plurality of input / output signal processing units step by step for each input / output signal processing unit according to the comparison result. To do.

  Preferably, there is a selection means for selecting either a reception process or a transmission process as a process for at least one of the second input / output signal processing units.

  In order to overcome the above problems, a second aspect of the present invention is a transmission / reception control method in a wireless communication apparatus that is operated by a battery and includes a plurality of antennas, the step of detecting the remaining amount of the battery, A part of the plurality of input / output signal processings for respectively processing the input / output signals for the plurality of antennas on the condition that the detection result is compared with the predetermined threshold and the detection result is less than the predetermined threshold. The step of stopping the power supply necessary for the input / output signal processing of the first and the first antenna corresponding to the first input / output signal processing that is the target of the power supply stop are not subject to the power supply stop due to the selection diversity. And a step used for the input / output signal processing in step (2).

The operation of the wireless communication apparatus of the present invention is as follows.
That is, the remaining amount detecting means detects the remaining amount of the battery. The power supply stopping unit compares the detected value with a predetermined threshold value, and stops power supply to a part of the plurality of input / output signal processing units on condition that the detected value falls below the predetermined threshold value. The connection switching means selectively selects the first antenna corresponding to the first input / output signal processing unit for which power supply has been stopped as the second input / output signal processing unit that is not subject to power supply stop due to selection diversity. Connect to. That is, all antennas including the first antenna are selectively used for reception or transmission.

  ADVANTAGE OF THE INVENTION According to this invention, the performance of the diversity transmission / reception by a some antenna can be optimally set according to the lifetime of a battery.

[Configuration common to each embodiment]
First, a general configuration common to each embodiment of the present invention will be described in association with FIGS. 1 to 3, and then a specific configuration of each embodiment will be described.
FIG. 1 is a block diagram showing a general configuration of a wireless communication device 1 according to an embodiment of the present invention.

As shown in FIG. 1, the wireless communication device 1 according to the present embodiment is configured by connecting a wireless communication unit 10, a system control unit 20, a power supply unit 30, and a memory 40 to a system bus 50.
The system control unit 20 is configured mainly with a microcontroller and a ROM / RAM, and controls the entire system of the wireless communication apparatus 1.
The power supply unit 30 includes a rechargeable battery 31 that supplies power to each unit of the wireless communication device 1 and a battery remaining amount detection unit 32 that detects the remaining amount (remaining capacity) of the battery. The memory 40 stores a threshold value to be compared with the detection result of the battery remaining amount detection unit 32.
The battery remaining amount detecting unit 32 is an embodiment of the remaining amount detecting means of the present invention.

  The wireless communication unit 10 includes a plurality of antennas and performs processing for performing wireless communication with the outside. The configuration of the wireless communication unit 10 will be described later.

The system control unit 20 receives the battery remaining amount detection result from the power supply unit 30 and compares the detection result with the threshold stored in the memory 40. A plurality of operation modes are set according to the comparison result. For example, either the normal mode or the low power consumption mode is set.
Here, the normal mode is a mode in which the detected battery remaining amount exceeds a predetermined threshold, and the low power consumption mode is a mode in which the detected battery remaining amount is below a predetermined threshold. Note that a plurality of threshold values can be set, and a plurality of low power consumption modes can be set according to the comparison result.

  The detection method of the battery remaining amount detection unit 32 in the power supply unit 30 can be realized by a plurality of methods. FIG. 2 illustrates some of them.

  FIG. 2A is a configuration diagram showing a detection method using a voltage measuring device. In this method, the battery remaining amount detection unit 32 includes a voltage measuring device 321 and a voltage reference table (data) 322. Here, the voltage measuring device 321 sequentially measures the instantaneous voltage of the battery 31. Based on the measured voltage, the remaining battery level is estimated with reference to the voltage reference table 322 in which the voltage characteristics of the battery 31 are written. This method is relatively simple and easy to implement.

  FIG. 2B is a configuration diagram showing a method using a current measuring device. In this method, the current output from the battery 31 and the current input to the battery 31 are always measured, and the remaining battery level is calculated. As shown in the figure, the current measuring device 323 is connected to the battery 31 and measures the current input and output from the battery 31. The integrator 324 is connected to the current measuring device 323, integrates the measured current value with time, and measures the amount of charge input to and output from the battery 31. Then, the remaining amount of the battery 31 is estimated based on the charge amount value measured by the microcontroller 325.

  FIG. 2C is a block diagram showing the simplest method using a timer. In this method, the timer is reset when charging is completed, the timer is counted down during use of the battery, and the remaining amount is estimated based on the time from the charging completion state to the discharging state. In this method, the battery remaining amount detection unit 32 includes a battery state detector 326 and a timer 327. The battery state detector 326 monitors the state of the battery 31 and controls the timer 327 based on the result. That is, when the battery 31 is fully charged, the timer 327 is reset, the battery 31 is used, and the timer 327 is counted down. In this method, assuming that the timer value is substantially proportional to the remaining battery level, the remaining battery level 31 is estimated based on the timer value.

Next, the configuration of the wireless communication unit 10 will be described with reference to FIG.
FIG. 3 is a block diagram illustrating a configuration of the wireless communication unit 10.

As illustrated in FIG. 3, the wireless communication unit 10 includes an antenna unit 11, a switch unit 12, a front end unit 13, a baseband unit 14, and a communication control unit 15.
The front end unit 13 is an embodiment of the input / output signal processing unit of the present invention.
The communication control unit 15 is an embodiment of the power supply stopping unit of the present invention.
The switch unit 12 and the communication control unit 15 are an embodiment of the connection switching means of the present invention.
The baseband unit 14 is an embodiment of the baseband processing unit of the present invention.

  The antenna unit 11 includes a plurality of antennas in order to perform reception diversity and / or transmission diversity. Diversity will be described later.

The front end unit 13 includes a plurality of radio transmission / reception units 131 to 13N corresponding to the plurality of antennas of the antenna unit 11. Each wireless transceiver includes a receiver and a transmitter (not shown) corresponding to the antenna.
The receiving unit demodulates the carrier signal received from the corresponding antenna into a baseband signal. For example, the receiving unit includes a bandpass filter for preventing interference from unnecessary frequency bands, a low noise amplifier (LNA) for amplifying the received signal, a mixer for demodulating the baseband signal, and the like. The
The transmission unit modulates the baseband signal into a carrier signal transmitted from the corresponding antenna. For example, the transmission unit includes a mixer for modulating the baseband signal.

  The baseband unit 14 performs various processes on the baseband signal. For example, the reception field strength (RSSI) of the baseband signal demodulated by each reception unit of the radio transmission / reception units 131 to 13N is measured, and the selection diversity processing (antenna selection processing) based on the measurement result is performed. Also, a synthesis diversity process for synthesizing baseband signals from a plurality of reception systems is performed. In addition, digital modulation / demodulation such as QPSK for transmission / reception signals, error correction encoding / decoding processing, and the like are also performed.

Here, in general, diversity (especially spatial diversity in this embodiment) is a technique that uses a plurality of antennas in order to compensate for deterioration in reception performance in a fading environment. There are several diversity schemes, but the two schemes that are most used are the above-described combination diversity and selection diversity.
Hereinafter, the outline of each scheme will be described with respect to combining diversity and selection diversity in reception diversity.

  Combining diversity is a method in which at least two receiving systems are provided, receiving signals from each antenna are simultaneously received, and receiving signals are combined in a baseband unit. This scheme has better reception quality than selection diversity, but consumes more power.

Unlike diversity combining, selection diversity has one receiving system. In this method, signals are selectively received from a plurality of antennas, signal strength is measured, and signals are received from an antenna having the best radio wave condition.
There are several methods for measuring radio wave conditions, but the most widely used methods are the received signal strength indicator (RSSI) and the correlation value between the received signals. Specifically, the first antenna is selected, the electric field strength or correlation value is measured when the signal level is stabilized, and the electric field strength or correlation value is measured in the same manner with the remaining antennas. The antenna having the maximum measured value is selected from the plurality of antennas measured in order, and a signal is received from the antenna and demodulated.
In the selection diversity, the reception quality is deteriorated as compared with the combined diversity, but the reception quality is excellent as compared with the case of the reception system having only a single antenna. In addition, since there is only one receiving system, it is superior in terms of power consumption as compared with combined diversity.

  In addition, it is possible to perform selection diversity at the time of transmission by using a plurality of antennas. Thereby, transmission quality can also be improved.

The communication control unit 15 supplies power from the battery 31 to one or more of the wireless transmission / reception units of the front end unit 13 according to the level of the low power consumption mode set by the system control unit 20. , The switch unit 12 is controlled to perform selective diversity, and the diversity operation in the baseband unit 14 is further controlled.
The control method by the communication control unit 15 will be described in the following embodiments in association with the drawings from FIG.

[First Embodiment]
Next, the configuration and operation of the wireless communication unit 10 in the wireless communication device 1 according to the first embodiment will be described with reference to FIGS. 4 and 5.
4 is a circuit configuration of the wireless communication unit 10 in the connection state in the normal mode, and FIG. 5 is a circuit configuration of the wireless communication unit 10 in the connection state in the low power consumption mode.
The configuration shown in FIG. 5 is different from the configuration shown in FIG.

  As shown in FIG. 4, the antenna unit 11 includes four antennas 111 to 114. The switch unit 12 includes two switches 121 and 122. The front end unit 13 includes a wireless transmission / reception unit 131 including a transmission unit 131a and a reception unit 131b, and a wireless transmission / reception unit 132 including a transmission unit 132a and a reception unit 132b. The antennas 111 to 114 correspond to the transmission unit 131a, the reception unit 131b, the transmission unit 132a, and the reception unit 132b, respectively.

The switches 121 and 122 are connected to the receiving unit 131b and the antenna 114, respectively, and are configured to include two contacts P1 and P2.
The contact P1 of the switch 121 is connected to the antenna 112, and the contact P2 is connected to the contact P2 of the switch 122. The contact P1 of the switch 122 is connected to the receiving unit 132b.

  Hereinafter, operations in the normal mode and the low power consumption mode will be described.

If the system control unit 20 determines that the remaining battery level detection value exceeds a predetermined threshold value stored in the memory 40, the system control unit 20 sends a control command to the communication control unit 15 to operate in the normal mode. Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10 to be performed in the normal mode.
In the normal mode, the radio transmission / reception units 131 and 132 of the front end unit 13 are both powered from the battery 31 and operate. In addition, as shown in FIG. 4, the contact P <b> 1 becomes conductive in the switch 121, and the contact P <b> 1 becomes conductive in the switch 122. Thereby, the signal received from the antenna 112 is processed by the receiving unit 131b, and the signal received by the antenna 114 is processed by the receiving unit 132b.

  The baseband unit 14 synthesizes the reception signals demodulated by the reception unit 131b and the reception unit 132b, and performs processing based on synthesis diversity to generate a baseband signal. Therefore, high reception quality is ensured.

On the other hand, when the system control unit 20 determines that the battery remaining amount detection value is lower than the predetermined threshold stored in the memory 40, the control command for operating in the low power consumption mode is sent to the communication control unit 15. . Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10 to be performed in the low power consumption mode.
That is, in the low power consumption mode, power supply to the wireless transmission / reception unit 132 of the front end unit 13 is stopped, and the contact P2 of the switch 122 is in a conductive state. Further, the switch 121 selectively switches the contacts P1 and P2 to sequentially turn on. The receiving unit 131b sequentially demodulates the signals received from the antennas 112 and 114 according to the switching timing of the switch 121.

  The baseband unit 14 compares the signal field strength (RSSI) of two baseband signals obtained by demodulating the signals received by the antenna 112 and the antenna 114, selects the larger baseband signal, and processes the signal ( Selection diversity). Therefore, it is possible to obtain a baseband signal having higher communication quality than processing the baseband signal based on the reception signal of only the antenna 112.

As described above, according to the wireless communication device 1 according to the present embodiment, in the normal mode, reception is performed with combined diversity using a plurality of antennas. When the remaining amount of the battery 31 is detected and falls below a predetermined threshold, the low power consumption mode is set. In the low power consumption mode, power supply to some of the wireless transmission / reception units of the front end unit 13 is stopped to extend the battery life, and an antenna corresponding to the wireless transmission / reception unit for which power supply has been stopped is used for selection diversity. .
Therefore, after entering the low power consumption mode, higher reception quality is ensured as compared with the case where the antenna corresponding to the wireless transmission / reception unit for which power feeding is stopped is not used. Further, in the selection diversity, since the received signal is selectively taken in, the power consumption in the low power consumption mode can be suppressed to the minimum.

[Second Embodiment]
Next, the configuration and operation of the wireless communication unit 10a in the wireless communication apparatus according to the second embodiment will be described with reference to FIG.

  FIG. 6 is a circuit configuration of the wireless communication unit 10a according to the present embodiment. The wireless communication unit 10a differs from the wireless communication unit 10 (see FIG. 4) according to the first embodiment in the configuration of the switch unit 12a.

That is, as illustrated in FIG. 6, the switch unit 12 a includes switches 122 to 124. The switch 122 is connected to the antenna 114, the switch 123 is connected to the receiving unit 131b, and the switch 124 is connected to the antenna 113.
Switches 122 and 124 include two contacts P1 and P2, respectively. The switch 123 includes three contacts P1 to P3. The contact P1 of the switch 122 is connected to the receiving unit 132b, and the contact P2 is connected to the contact P3 of the switch 123. The contact P1 of the switch 123 is connected to the antenna 112, and the contact P2 is connected to the contact P2 of the switch 124. A contact P1 of the switch 124 is connected to the transmission unit 132a.

  Hereinafter, the operation of the wireless communication unit 10a will be described.

If the system control unit 20 determines that the remaining battery level detection value exceeds a predetermined threshold value stored in the memory 40, the system control unit 20 sends a control command to the communication control unit 15 to operate in the normal mode. Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10a to be performed in the normal mode.
In the normal mode, the radio transmission / reception units 131 and 132 of the front end unit 13 are both powered from the battery 31 and operate. In addition, the contact P1 becomes conductive in the switch 123, the contact P1 becomes conductive in the switch 124, and the contact P1 becomes conductive in the switch 122. Thereby, the signal received from the antenna 112 is processed by the receiving unit 131b, and the signal received by the antenna 114 is processed by the receiving unit 132b.

  The baseband unit 14 synthesizes the reception signals demodulated by the reception unit 131b and the reception unit 132b, and performs processing based on synthesis diversity to generate a baseband signal. Therefore, high reception quality is ensured.

On the other hand, when the system control unit 20 determines that the battery remaining amount detection value is lower than the predetermined threshold stored in the memory 40, the control command for operating in the low power consumption mode is sent to the communication control unit 15. . Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10a to be performed in the low power consumption mode.
That is, in the low power consumption mode, power supply to the wireless transmission / reception unit 132 of the front end unit 13 is stopped, the contact P2 of the switch 124 is turned on, and the contact P2 of the switch 122 is turned on. Further, the switch 123 selectively switches the contacts P1 to P3 to sequentially turn on. Then, the receiving unit 131b sequentially demodulates the signals received from the antennas 112 to 114 in accordance with the switching timing of the switch 123.

  The baseband unit 14 compares signal field strengths (RSSI) of three baseband signals obtained by demodulating signals received by the antennas 112 to 114, selects the largest baseband signal, and processes the signal (selection diversity). ). Therefore, compared with the case where the baseband signal is processed with the reception signal of only the antenna 112 or the case where the selection diversity is performed based only on the reception signals of the antenna 112 and the antenna 114 (first embodiment), the communication quality is higher. A high baseband signal can be obtained.

As described above, the reception performance of the selected diversity in the low power consumption mode can be enhanced by making maximum use of the antennas (antennas 113 and 114) corresponding to the wireless transmission / reception units whose power supply has been stopped.
As is clear from the configuration of FIG. 6, the number of antennas is not limited to four, and can be easily extended to a wireless communication device using more antennas. In such a case, a switch corresponding to each antenna is provided, and a switch having the number of contacts corresponding to the number of antennas is set as the switch 123 in FIG. In the low power consumption mode, the contact is switched so as to sequentially select the output of the antenna corresponding to the wireless transmission / reception unit for which power feeding has been stopped.

[Third Embodiment]
Next, the configuration and operation of the wireless communication unit 10b in the wireless communication apparatus according to the third embodiment will be described with reference to FIG.
In the wireless communication unit 10b according to the present embodiment, the front end unit includes three wireless transmission / reception units, and power supply to the wireless transmission / reception units is stopped stepwise according to the detection result of the remaining battery level.

FIG. 7 is a circuit configuration of the wireless communication unit 10b according to the present embodiment.
The wireless communication unit 10b includes an antenna unit 11a, a switch unit 12b, a front end unit 13a, a baseband unit 14, and a communication control unit 15.

  As illustrated in FIG. 7, the antenna unit 11 a includes six antennas 111 to 116. The switch unit 12b includes four switches 125 to 128. The front end unit 13a includes a wireless transmission / reception unit 131 including a transmission unit 131a and a reception unit 131b, a wireless transmission / reception unit 132 including a transmission unit 132a and a reception unit 132b, and a wireless transmission / reception unit 133 including a transmission unit 133a and a reception unit 133b. Have The antennas 111 to 116 correspond to the transmission unit 131a, the reception unit 131b, the transmission unit 132a, the reception unit 132b, the transmission unit 133a, and the reception unit 133b, respectively.

The switches 125 to 128 are connected to the receiving unit 131b, the antenna 115, the receiving unit 132b, and the antenna 116, respectively, and include two contact points P1 and P2.
The contact P1 of the switch 125 is connected to the antenna 112, and the contact P2 is connected to the contact P2 of the switch 126. The contact P1 of the switch 126 is connected to the transmission unit 133a. The contact P1 of the switch 127 is connected to the antenna 114, and the contact P2 is connected to the contact P2 of the switch 128. The contact P1 of the switch 128 is connected to the receiving unit 133b.

  Hereinafter, operations in the normal mode and the low power consumption mode will be described.

If the system control unit 20 determines that the remaining battery level detection value exceeds a predetermined threshold value stored in the memory 40, the system control unit 20 sends a control command to the communication control unit 15 to operate in the normal mode. Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10b to be performed in the normal mode.
In the normal mode, the wireless transmission / reception units 131 to 133 of the front end unit 13a are both operated by being supplied with power from the battery 31. In addition, the contact P1 is turned on in the switch 125, the contact P1 is turned on in the switch 126, the contact P1 is turned on in the switch 127, and the contact P1 is turned on in the switch 128. Thus, a signal received from the antenna 112 is processed by the receiving unit 131b, a signal received by the antenna 114 is processed by the receiving unit 132b, and a signal received from the antenna 116 is processed by the receiving unit 133b.

  The baseband unit 14 synthesizes the reception signals demodulated by the reception units 131b to 133b and generates a baseband signal by performing processing based on synthesis diversity. Therefore, high reception quality is ensured.

On the other hand, when the system control unit 20 determines that the remaining battery level detection value is lower than a predetermined first threshold stored in the memory 40, the communication control unit 15 operates in the first low power consumption mode. The control command is sent. Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10b to be performed in the first low power consumption mode.
In the first low power consumption mode, power supply to the wireless transmission / reception unit 133 of the front end unit 13a is stopped, the contact P2 of the switch 126 is turned on, and the contact P2 of the switch 128 is turned on. Further, the switches 125 and 127 selectively switch the contacts P1 and P2 to sequentially turn on. The receiving unit 131b sequentially demodulates the signals received from the antennas 112 and 115 in accordance with the switching timing of the switch 125. The receiving unit 132b sequentially demodulates the signals received from the antennas 114 and 116 in accordance with the switching timing of the switch 127.

  The baseband unit 14 compares signal field strengths (RSSI) of four baseband signals obtained by demodulating signals received by the antennas 112, 114, 115, and 116, and selects a large baseband signal (selection diversity). Further, the selection result of two baseband signals obtained by demodulating the signals received by the antennas 112 and 115 may be combined with the selection result of two baseband signals obtained by demodulating the signals received by the antennas 114 and 116 ( Synthetic diversity).

Further, when the system control unit 20 determines that the battery remaining amount detection value is below a predetermined second threshold value (a value smaller than the first threshold value) stored in the memory 40, the communication control unit 15 A control command for operating in the second low power consumption mode is transmitted. Thereby, the communication control unit 15 controls the operation of each unit of the wireless communication unit 10b to be performed in the second low power consumption mode.
In the second low power consumption mode, power supply to the radio transmission / reception units 132 and 133 of the front end unit 13a is stopped, and the contact P2 of the switch 126 is turned on. Furthermore, the switch 125 selectively switches the contacts P1 and P2 to sequentially turn on. The receiving unit 131b sequentially demodulates the signals received from the antennas 112 and 115 in accordance with the switching timing of the switch 125.

  The baseband unit 14 compares the signal field strengths (RSSI) of two baseband signals obtained by demodulating the signals received by the antennas 112 and 115, and selects the larger baseband signal (selection diversity). Since the selectable antenna is limited, the reception quality in the second low power consumption mode is deteriorated as compared with the reception quality in the first low power consumption mode, but the base is based on the reception signal of only the antenna 112. Compared with the case of processing a band signal, the reception quality is high.

As described above, in the present embodiment, in the wireless communication device having three or more reception systems, a plurality of low power consumption modes are set according to the remaining battery level, and the front-end unit wireless transmission / reception unit is stepwise. Stop power supply. As in the wireless communication apparatus described in the first embodiment, in the low power consumption mode, the antenna corresponding to the wireless transmission / reception unit in which the battery is extended and power supply is stopped is used for selection diversity. . That is, by stopping the power supply to the front end unit step by step, the balance between reception quality and battery life time can be set flexibly.
For a wireless communication unit including a wireless transmission / reception unit having more than three front end units, a switch corresponding to the antenna is provided accordingly, so that the configuration shown in FIG. 7 can be easily expanded and adapted. It is possible.
[Fourth Embodiment]
Next, a wireless communication unit 10c in the wireless communication apparatus according to the fourth embodiment will be described with reference to FIG.
In the wireless communication unit 10 according to the first embodiment, only selection diversity is received in the low power consumption mode. However, in the wireless communication unit 10c according to the present embodiment, selection diversity in the low power consumption mode is received and transmitted. The purpose is to do both.

FIG. 8 is a circuit configuration of the wireless communication unit 10c according to the present embodiment.
The wireless communication unit 10c differs from the wireless communication unit 10 (see FIG. 4) according to the first embodiment in the configuration of the antenna unit and the switch unit.

That is, as illustrated in FIG. 8, the switch unit 12 c is added with a switch 129 for selecting either the reception process or the transmission process as compared with the switch unit 12 of the wireless communication unit 10, and the transmission unit A single antenna 111 shared with 131a and receiving unit 131b is provided. The switch 129 is provided between the switch 121 and the wireless transmission / reception unit 131 and has two contact points P1 and P2. The contact P1 of the switch 129 is connected to the transmitter 131a, and the contact P2 is connected to the receiver 131b.
The switch 129 is an embodiment of the selection unit of the present invention.

The switch 129 is controlled by the communication control unit 15 so that the contact P2 is in a conducting state when receiving, and the contact P1 is in a conducting state when transmitting.
The controls for the switches 121 and 122 in the normal mode and the low power consumption mode are the same as those in the wireless communication unit 10 described in the first embodiment.
As a result, in the low power consumption mode, selection diversity using the antennas 111 and 114 can be performed in both reception and transmission.

  Although the first to fourth embodiments of the present invention have been described above, the contents of the embodiments may be combined as appropriate. The embodiments of the present invention are not limited to the above-described embodiments, and those skilled in the art can make various modifications without departing from the scope of the present invention.

For example, in the first to third embodiments, in each wireless transmission / reception unit of the front end unit, the transmission unit and the reception unit are associated with independent antennas, but the transmission / reception described in the fourth embodiment By appropriately adding a selection switch 129, each wireless transmission / reception unit can operate with a single antenna.
In each of the above embodiments, the selection diversity for reception is mainly described in the low power consumption mode. However, it is easily modified by those skilled in the art to modify the selection diversity for transmission. It is possible content. For example, in the wireless communication unit 10a shown in FIG. 6, the switches 123 and 124 are set so that the transmission signal supplied from the transmission unit 132a in the low power consumption mode is transmitted by selecting either the antenna 112 or the antenna 113. Changing is easily conceivable.

1 is a system configuration diagram of a wireless communication device 1 which is an embodiment of a wireless communication device of the present invention. It is a figure which shows some structural examples of a battery remaining charge detection part. It is a block diagram which shows the structure of the radio | wireless communication part which concerns on embodiment. In 1st Embodiment, it is a figure which shows the circuit structure of the radio | wireless communication part in the connection state of normal mode. In 1st Embodiment, it is a figure which shows the circuit structure of the radio | wireless communication part in the connection state of a low power consumption mode. It is a figure which shows the circuit structure of the radio | wireless communication part which concerns on 2nd Embodiment. It is a figure which shows the circuit structure of the radio | wireless communication part which concerns on 3rd Embodiment. It is a figure which shows the circuit structure of the radio | wireless communication part which concerns on 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless communication apparatus, 10 ... Wireless communication part, 11, 11a, 11b ... Antenna part, 12, 12a, 12b, 12c ... Switch part, 13, 13a ... Front end part, 131-13N ... Wireless transmission / reception part, 14 ... Baseband unit, 15 ... communication control unit, 20 ... system control unit, 30 ... power supply unit, 31 ... battery, 32 ... battery remaining amount detection unit, 40 ... memory, 50 ... system bus.

Claims (7)

A wireless communication device operated by a battery,
Multiple antennas,
A plurality of input / output signal processing units connected corresponding to each antenna;
A remaining amount detecting means for detecting the remaining amount of the battery;
A power supply stopping unit that compares a detection value by the remaining amount detection unit with a predetermined threshold value and stops power supply to a part of the plurality of input / output signal processing units on condition that the detection value falls below the predetermined threshold value When,
A connection for selectively connecting the first antenna corresponding to the first input / output signal processing unit subject to power supply stop to the second input / output signal processing unit not subject to power supply stop for selection diversity Switching means;
A wireless communication device comprising: A baseband processing unit that is connected to the plurality of input / output signal processing units and processes a baseband signal;
The radio communication apparatus according to claim 1, wherein the baseband processing unit processes a baseband signal by combining diversity using the plurality of antennas on condition that a detection value by the remaining amount detection unit exceeds the predetermined threshold. The connection switching means includes a switch having a plurality of contacts connected to an antenna corresponding to the second input / output signal processing unit and at least a part of the one or more first antennas. The wireless communication apparatus according to claim 1, wherein contact points of the first and second terminals are sequentially conducted to selectively supply an antenna output to the second input / output processing unit. The power supply stopping unit compares the detected value with a plurality of threshold values, and stops power supply to the plurality of input / output signal processing units step by step for each input / output signal processing unit according to the comparison result. The wireless communication device described. The wireless communication apparatus according to claim 1, further comprising selection means for selecting either reception processing or transmission processing as processing for at least one of the second input / output signal processing units. The connection switching means includes a first switch having a plurality of contacts connected to an antenna corresponding to the second input / output signal processing unit and at least a part of the one or more first antennas. ,
The wireless communication according to claim 5, wherein the selection unit includes a second switch that is connected to the first switch and switches either reception processing or transmission processing as processing for the second input / output signal processing unit. apparatus. A transmission / reception control method in a wireless communication device that operates by a battery and includes a plurality of antennas,
Detecting the remaining amount of the battery;
Comparing the detection result with a predetermined threshold;
A step of stopping power feeding required for some input / output signal processing among the plurality of input / output signal processing for respectively processing the input / output signals for the plurality of antennas on condition that the detection result falls below the predetermined threshold. When,
Using the first antenna corresponding to the first input / output signal processing subject to power supply suspension for the second input / output signal processing not subject to power suspension for selection diversity;
A transmission / reception control method in a wireless communication apparatus.

Images