JP2002111558A - Apparatus and method for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for communication where proper diversity effect is attained, while seducing power consumption in a communication device provided with a plurality of receiving circuits. SOLUTION: A communication device 1 is provided with reception circuits 23 and 24 in a plurality of systems to accommodate a variety of communication methods, including high-speed data transmission and telephone conversation/low- speed data transmission. In telephone conversation/low-speed data transmission, if the receiving level is higher than a specified threshold, a first diversity method where one of the reception circuits in the plurality of the systems is selected and actuated on a receiving slot-by-receiving slot basis and power supply to the non-selected reception circuits is interrupted. In unfavorable receiving conditions, a second diversity method where any detection output in the reception circuits in the plurality of the systems is selected on a symbol-by-symbol basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication apparatus and a communication method, and more particularly, to diversity control in a communication apparatus.

[0002]

2. Description of the Related Art PDC (Personal Digital Cellular)
When performing a voice call and low-speed data transmission, a communication device of the TDMA scheme uses TDMA (Time Division Multip
le Access). In recent years,
There is an increasing demand for a high-speed data transmission function in addition to a voice communication function in such a communication device. When high-speed data transmission is performed in a communication device of the PDC system, communication is performed by a full-duplex full-slot reception system in which continuous full-slot reception is performed.

[0003] In a communication device of the PDC system, diversity control is performed as a countermeasure for fading. Conventional diversity systems are roughly classified into a selection diversity system after detection and an antenna switching diversity system.

[0004] Hereinafter, a conventional post-detection selection diversity system and an antenna switching diversity system will be described with reference to Figs.

FIG. 7 is a block diagram showing a configuration of a transmission / reception circuit 101 of a conventional post-detection selection diversity system.
FIG. 8 is a diagram showing transmission / reception timing in the conventional post-detection selection diversity system. As shown in FIG. 7, the transmission / reception circuit 101 of the selective diversity system after detection includes an antenna ANT1 for both transmission and reception and an antenna ANT2 for reception.
And a transmission circuit 103, two-system reception circuits 104 and 105
It consists of. Antenna ANT1 is duplexer 1
02 is connected to the transmission circuit 103 and the reception circuit 104 via the same. The antenna ANT2 is connected to the receiving circuit 105.
It is connected to the.

[0006] The two systems of receiving circuits 104 and 105 respectively convert a high-frequency signal (hereinafter, referred to as an RF signal) received by the antennas ANT1 and ANT2 from a received electric field strength (Re.
ceived Signal Strength Indication;
Are measured and supplied to a digital processing unit (not shown). In the digital processing unit, the R output from each of the receiving circuits 104 and 105 in units of received symbols (one symbol is about 47 μsec)
The SSI1 signal is compared with the RSSI2 signal, and the detection output with the higher reception level is selected. Alternatively, the detection output with the lower bit error rate is selected.

As described above, in the post-detection selection diversity system, the reception level is determined for each symbol and the detection output from the reception circuit having a high reception level is selected, so that a large bit rate can be obtained and a large diversity effect can be obtained. it can. However, as shown in FIG. 8, it is necessary to always supply power to the two-system receiving circuits 104 and 105 to perform a receiving operation. Therefore, power consumption increases.

Next, a conventional antenna switching diversity system will be described. FIG. 9 is a block diagram showing a configuration of a conventional antenna switching diversity transmission / reception circuit 111, and FIG. 10 is a diagram showing transmission / reception timing in a conventional antenna switching diversity system.

As shown in FIG. 9, a transmitting / receiving circuit 111 of the antenna switching diversity system has two antennas AN.
T1, ANT2, antenna switch 112, transmission circuit 1
13, the receiving circuit 114. The antenna switch 112 is a switch for switching between the two antennas ANT1 and ANT2, and the switching operation is controlled by a digital processing unit.

In this antenna switching diversity system, as shown in FIG. 10, the reception levels (RSSI) of the two antennas ANT1 and ANT2 are determined in the LM section immediately before the reception slot (one slot is about 6.6 msec). The antenna is switched to an antenna having a higher reception level, and the antenna used in the reception slot section is fixed. In the next reception slot, similarly, in the immediately preceding LM section, both antennas ANT are used.
1, the reception level at ANT2 is measured, and the antenna is switched to an antenna having a higher reception level for use. For this reason, it is not possible to cope with a change in the reception level in the reception slot section, and the diversity effect is smaller than that of the post-detection selection diversity system in which diversity is performed in symbol units. However, since the receiving circuit can be configured by one system, power consumption is reduced.

In full-duplex, full-slot reception at the time of high-speed data transmission, 2
Since the receiving operation is performed in the receiving circuit of the system, it is not possible to employ the antenna switching diversity system, and it is necessary to employ the selection diversity system after detection.

As described above, in a communication apparatus that supports both full-duplex full-slot reception in high-speed data transmission and TDMA reception in voice communication and low-speed data transmission, a selection diversity scheme after detection is adopted as a diversity scheme. ing.

[0013]

However, when the post-detection selection diversity system having a high diversity effect is employed, there is a problem that the power consumption is increased and the talk time and the standby time are shortened.

An object of the present invention is to provide a communication apparatus compatible with a communication system including, for example, full-duplex full-slot reception in high-speed data transmission or TDMA reception in voice communication or low-speed data transmission, while obtaining a good diversity effect. An object of the present invention is to provide a communication device and a communication method capable of reducing power consumption.

[0015]

In order to solve such a problem, the invention according to claim 1 includes a plurality of receiving circuits (for example, receiving circuits 23 and 24 shown in FIG. 2) and performs a receiving process. A communication unit for performing a determination on a receiving state in the receiving circuit (for example, the digital processing unit 3 shown in FIG. 1; S6 in FIG. 3); The first diversity method for selecting and operating any of the plurality of receiving circuits, or the second diversity method for selecting any of the detection outputs in the plurality of receiving circuits for each received symbol. Diversity switching means (for example, a digital processing unit shown in FIG. 1; S7 and S8 in FIG. 3) for switching between crabs and power supply to each receiving circuit according to a diversity system are controlled. To power control means (e.g., Fig. 1
Digital processing unit 3 shown in FIG. 2, power supply control unit 25 shown in FIG.
S7 and S8 in FIG. 3).

According to the first aspect of the present invention, the diversity system is switched to the diversity system according to the reception state by the determining unit, the diversity switching unit, and the power control unit.
The power supply to the receiving circuit is controlled according to the diversity system.

According to a sixth aspect of the present invention, there is provided a communication method in a communication device including a plurality of receiving circuits and performing a receiving process, wherein a determining step of determining a receiving state in the receiving circuit, According to the determination result by
A first diversity scheme for selecting and operating any of the plurality of reception circuits in units of reception slots, or a second diversity for selecting any detection output in the plurality of reception circuits in units of reception symbols It is characterized by comprising a diversity switching step of switching to any one of the methods, and a power control step of controlling power supply to each receiving circuit according to the diversity method.

According to the communication method of the present invention, in a communication apparatus having a plurality of receiving circuits and performing a receiving process, a discriminating step, a diversity switching step,
By the power control step, switching to the diversity system according to the reception situation is performed, and power supply to the receiving circuit is controlled according to the diversity system.

Therefore, according to the first and sixth aspects of the present invention, it is possible to reduce power consumption while obtaining a good diversity effect in a communication device having a plurality of receiving circuits.

In the communication apparatus according to the first aspect of the present invention, the diversity switching means switches to the first diversity scheme when reception conditions are good, and otherwise, It is effective to switch to the second diversity system, and when the power supply control unit is switched to the first diversity system, cut off power supply to a non-selected receiving circuit in a reception slot section.

In the communication method according to the sixth aspect of the present invention, in the diversity switching step, when the reception condition is good, the first diversity mode is switched, and in other cases, the first diversity mode is switched. It is effective to switch to the second diversity scheme and to cut off the power supply to the non-selected receiving circuit in the reception slot section when switching to the first diversity scheme in the power control step.

According to the second and seventh aspects of the present invention, if the receiving condition is good, the power consumption in the receiving circuit can be reduced.
If the reception situation is not good, a reception operation with a high diversity effect can be performed and good reception quality can be maintained.

According to a third aspect of the present invention, in the communication apparatus according to the first or second aspect, the receiving process includes a receiving process corresponding to high-speed data transmission and a voice communication or low-speed data transmission. Includes corresponding receive processing,
The diversity switching means switches to the second diversity method at the time of high-speed data transmission, and switches to either the first or second diversity method at the time of voice communication or low-speed data transmission in accordance with the result of determination by the determination means. (For example, the digital processing unit 3 shown in FIG. 1; S1 in FIG. 3) is effective.

In the communication method according to the sixth or seventh aspect, the reception processing includes a reception processing corresponding to a high-speed data transmission and a voice communication or a low-speed data transmission. Includes corresponding receive processing,
The diversity switching step switches to the second diversity mode during high-speed data transmission, and switches to either the first or second diversity mode during voice communication or low-speed data transmission according to the determination result in the determination step. It is effective.

According to the third and eighth aspects of the present invention, in a communication apparatus compatible with various communication systems such as high-speed data transmission and voice communication or low-speed data transmission, power consumption is reduced while obtaining a good diversity effect. It is possible to do.

According to a fourth aspect of the present invention, in the communication apparatus according to any one of the first to third aspects, the reception electric field strength may be used to determine a reception state.
Further, as in the invention according to claim 5, in the communication apparatus according to any one of claims 1 to 3, the bit error rate may be used to determine the reception status.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a communication apparatus according to the present invention. First, the configuration will be described. FIG. 1 is a block diagram illustrating a configuration of a communication device 1 according to the present embodiment. As shown in FIG.
Is a high frequency unit 2, a digital processing unit 3, an audio unit 4,
Display unit 5, operation unit 6, microphone 7, speaker 8, data I
/ O terminal 9 is provided. The communication device 1 of the present embodiment is equipped with two types of transmission systems, a high-speed data transmission system and a voice communication / low-speed data transmission system, and performs full-duplex / full-slot reception processing in high-speed data transmission. In voice communication and low-speed data transmission, TDMA reception processing is performed.

FIG. 2 shows the internal configuration of the high-frequency section 2. FIG.
As shown in FIG.
NT1, a receiving antenna ANT2, a duplexer 21,
It comprises a transmission circuit 22, two systems of reception circuits 23 and 24, a power supply control unit 25, and local oscillators 26, 27 and 28. The transmitting circuit 22 and the receiving circuit 23 are connected to the antenna ANT1 via the duplexer 21.
The receiving circuit 24 is connected to NT2.

The transmission circuit 22 includes a modulator 221, a band-pass filter (hereinafter referred to as BPF) 222, and a mixer (MI
X) 223, BPF 224, amplifier (AMP) 225,
And a low-pass filter (hereinafter, referred to as LPF) 226, supplied from the digital processing unit 3,
The Q signal is shifted by π / 4 shift by the modulator 221 in the 4-phase QPS.
After performing K modulation and extracting necessary frequency components by the BPF 222, the MIX 223 mixes with a signal corresponding to the set channel supplied from the local oscillator 27, and further mixes the BPF 224, the amplifier 225, and the LPF 2
A required frequency component is extracted by 26 and power-amplified, and transmitted from the antenna ANT1 via the duplexer 21.

The receiving circuit 23 includes a BPF 231 and an amplifier 2
32, a BPF 223, a mixer 234, a BPF 235, and an IF IC 236.
BPF 231 and amplifier 2 from the RF signal input from
32, necessary frequency components are taken out by the BPF 233, and after power amplification, they are mixed with the reference clock generated by the local oscillator 28 by the mixer 234,
The IF signal 1 is extracted by the BPF 235 and the IFIC 236 and output to the digital processing unit 3. Further, the receiving circuit 23 measures the RSSI in the ANT 1 and outputs the RSSI signal 1 to the digital processing unit 3.

Since the receiving circuit 24 has the same configuration as the receiving circuit 23, the description thereof is omitted. The receiving circuit 2
Each IF signal output from 3, 24 is an IF1 signal,
Each of the RSSI signals output from the receiving circuits 23 and 24 is called an RSSI1 signal and an RSSI2 signal, respectively. Each of the receiving circuits 23 and 24 includes a power control unit 25.
The power supply is independently controlled in accordance with the power supply control signal from the power supply.

The power control section 25 outputs a power control signal to the receiving circuits 23 and 24 in accordance with the RX1 control signal and the RX2 control signal supplied from the digital processing section 3, respectively. Controls the supply / interruption of power to the For example, when switching to the symbol unit diversity system (details will be described later) is performed by the diversity switching process (see FIG. 3) described later, the reception circuit 23
And the receiving circuit 24. Also, when switching to the slot-based diversity system (details will be described later), power is supplied to each of the receiving circuits 23 and 24 in the LM section immediately before the receiving slot, but in the subsequent slot section, the receiving circuits 23 and 24 are supplied. Of these, the power is supplied only to the receiving circuit having a good receiving condition, and the power supply to the other receiving circuit (non-selected receiving circuit) is cut off.

The local oscillators 26, 27 and 28 determine the tuning frequencies in the transmission circuit 22 and the reception circuits 23 and 24, and generate reference clocks.

In the receiving system, the digital processing unit 3 converts the IF1 signal and the IF2 signal supplied from the receiving circuits 23 and 24 into digital data using an A / D converter and outputs π / 4.
After the shift 4-phase QPSK demodulation, TDMA processing is performed.
For the audio signal portion of the data after the TDMA processing, VS
After the ELP process and the D / A conversion process are performed, the signal is output to the audio unit 4 as a received voice signal. The data portion such as a message is subjected to TDMA processing and error correction processing after demodulation. In the transmission system, the transmission voice supplied from the audio unit 4 is converted into an ADPCM / PCM digital signal by an A / D converter,
P processing is performed. In addition, code conversion and error correction processing are performed on a data portion such as a message. Digital data such as these voices and data is subjected to TDMA processing,
The signal is output to the high frequency unit 3 as a Q signal. In addition, each RSSI value (RSSI1 signal,
The reception status is determined by comparing the RSSI2 signal) and the bit error rate with a predetermined threshold.

The digital processing unit 3 executes a diversity switching process (see FIG. 3) described later, and
When any one of the high-speed data transmission mode and the voice communication / low-speed data transmission mode is selected based on a key operation signal from the user or the like, the diversity system is switched according to the selected communication mode. The power supply to the receiving circuits 23 and 24 is controlled according to the diversity system.

In the present embodiment, the diversity system includes a slot-based diversity system (first diversity system) in which one of the receiving circuits 23 and 24 having a good reception condition is selected and operated for each reception slot. , And a symbol unit diversity system (second diversity system) for selecting any of the detection outputs in the reception circuits 23 and 24 for each reception symbol.

In the high-speed data transmission mode, the same full-duplex / full-slot reception as in the prior art is performed.
Switching to the symbol unit (one or a plurality of symbol units) diversity system is performed, and the RX1 control signal and the RX2 control signal are output to the power control unit 25 so as to supply power to the two receiving circuits 23 and 24, respectively.

In the voice call / low-speed data transmission mode, first, the RSSI of the currently selected receiving circuit is measured.
This RSSI is compared with a predetermined threshold value (for example, 20 dBu). If the RSSI exceeds the threshold value, it is determined that the reception status is good, and the diversity system is switched to the slot unit (one or a plurality of slot units). At this time, power is supplied to each of the receiving circuits 23 and 24 in the LM section immediately before the receiving slot, the RSSI is measured, and a receiving circuit having a good receiving condition is selected. The operation is performed, and the other non-selected receiving circuit is instructed to supply power to the power control unit 25 so as to shut off the power during the slot section.
1 control signal and RX2 control signal. Also, RSS
If I is equal to or smaller than a predetermined threshold, the system switches to the symbol unit diversity system. At this time, the two receiving circuits 23, 2
RX1 control signal, RX2
The control signal is output to the power control unit 25.

In the present embodiment, the reception status is determined based on the RSSI size and switching to the appropriate diversity system is performed. However, the reception status is determined based on the bit error rate and switching to the appropriate diversity system is performed. You may do so. That is, if the bit error rate of each of the receiving circuits 23 and 24 is smaller than a predetermined threshold, a slot-based diversity scheme is adopted, and if the bit error rate is larger than a predetermined threshold, a symbol-based diversity scheme is adopted.

The audio unit 4 converts an audio signal input through the microphone 7 into an electric signal, supplies the electric signal to the digital processing unit 3 as a transmission audio signal, and converts the reception audio signal supplied from the digital processing unit 3 into an electric signal. The power is amplified and sound is output from the speaker 8.

The display unit 5 includes an LED, a liquid crystal display panel, and the like, and performs display according to display data supplied from the digital processing unit 3. The operation unit 6 includes a communication mode selection key (may be controlled by an external device such as a connected personal computer), a dial number input key, an on-hook,
A key group such as an off-hook key is provided, and an input key operation signal is output to the digital processing unit 3.

Next, the operation will be described with reference to FIGS. FIG. 3 is a flowchart for explaining diversity switching processing performed in the communication apparatus 1. FIG. 4 is a diagram showing transmission / reception timing during high-speed data transmission. FIG. 5 is a diagram illustrating a slot-based diversity scheme during voice communication / low-speed data transmission. FIG. 6 is a diagram showing a graph showing a change over time in the reception level and a manner of switching the diversity system according to the transmission / reception data at the time of voice / low-speed data transmission.

As shown in the flowchart of FIG. 3, when one of the high-speed data transmission mode and the voice communication / low-speed data transmission mode is selected based on a key operation signal from the operation unit 6 (step S1). ), The digital processing unit 3 switches the diversity system according to the selected communication mode and controls the power supply to the receiving circuits 23 and 24. That is, when the high-speed data transmission mode is selected (step S2), in order to perform the full-duplex full-slot reception as in the related art, control is performed so that power is supplied to the two-system reception circuits 23 and 24, respectively. During reception, the mode is switched to the symbol unit diversity system.

As shown in the transmission / reception timing chart of FIG.
In the symbol-based diversity system in the high-speed data transmission mode, the power is always supplied to the two receiving circuits 23 and 24 so that the two receiving circuits 23 and 24 perform a continuous receiving operation.
From the receiving circuits 23 and 24 in symbol units by
The SSI1 signal and the RSSI2 signal are compared, and the detection output of the receiving circuit having a high receiving level is selected.

In the voice communication / low-speed data transmission mode (step S4), TDMA communication is performed. First, the digital processing unit 3 checks the RSSI in the currently selected receiving circuit.
Is measured (step S5), and if the RSSI is larger than a predetermined threshold (for example, 20 dBu) (step S6; Y
ES), the mode is switched to the slot-based diversity system, and at this time, the RX1 control signal and the RX1 are sent to the power control unit 25 so as to shut off the power of the non-selected receiving circuit until the next LM section.
2 A control signal is output (step S7).

As shown in the transmission / reception timing chart of FIG.
In the slot unit diversity system, one of the two receiving circuits 23 and 24 is selected for each receiving slot to perform a receiving operation. That is, the digital processing unit 3 supplies power to each of the receiving circuits 23 and 24 to perform the RSSI measurement in the LM section immediately before the reception slot, and makes the RSSI 1
The signal and the RSSI2 signal are compared, and a reception circuit having a high reception level is selected. In this reception slot section, power is supplied only to the selected reception circuit, and power supply to the reception circuit having a low reception level is cut off. Accordingly, since only one of the receiving circuits is used, power consumption is reduced. If a sufficiently high value is set as the threshold value, sufficient reception quality can be ensured without performing diversity (receiving circuit switching) within the slot section.

In the voice communication / low-speed data transmission mode, if the RSSI is smaller than the predetermined threshold (step S6; NO), the system switches to the symbol-based diversity system and supplies power to the two-system receiving circuits 23 and 24, respectively. An RX1 control signal and an RX2 control signal are output to the power supply control unit 25 so as to be supplied. In addition, the detection output of the receiving circuit having the high receiving level is selected for each symbol (step S8). The transmission / reception timing in this case is the same as that of the conventional post-detection selection diversity system (see FIG. 8). That is, when the reception level is low, switching to the symbol-based diversity scheme having a high diversity effect is performed, so that the reception quality can be ensured with priority.

Thereafter, in the voice call / low-speed data transmission mode, the RS of the currently selected receiving circuit is changed every predetermined time.
The SI is measured, and the diversity system is switched (steps S5 to S8).

FIG. 6 shows the time lapse of the diversity system switching in the voice communication / low-speed data transmission mode. FIG. 6A is a graph showing the time change of the reception level (RSSI), the vertical axis represents the reception level (unit is dBu), the horizontal axis represents time, and FIG. 6B is the graph of FIG. The state of switching of the corresponding diversity system is shown.

When the reception level is a predetermined threshold (here, 20
If it exceeds dBu), the mode is switched to the slot-based diversity scheme. At this time, power supply to the non-selected receiving circuit is cut off in each slot section, so that power consumption can be reduced. If the reception level becomes equal to or less than the threshold value at time t1 after a certain time has elapsed, the system is switched to the symbol unit diversity system. At this time, power is supplied to all the receiving circuits as in the case of the normal selection diversity system after detection, but a good diversity effect can be obtained. If the reception level exceeds the threshold at time t2 after a further elapse of time, switching is made to slot-based diversity.

As described above, the communication device 1 of the present embodiment operates in the high-speed data transmission mode or
A plurality of receiving circuits are provided to support various communication modes such as a low-speed data transmission mode, and the diversity system is switched according to the communication mode to be used. In the high-speed data transmission mode, the mode is switched to the symbol-based diversity mode, and in the low-speed communication mode, the mode is switched to the slot-based diversity mode or the symbol-based diversity mode according to the reception level. If the reception level is higher than the predetermined threshold, the mode is switched to the slot diversity system, and the power supply to the non-selected reception circuits is cut off. At this time, diversity is not performed in the slot section, but the reception level is sufficiently high, so that the reception quality is not impaired. If the reception level is lower than the predetermined threshold, the system switches to the symbol-based diversity system having a high diversity effect, and the reception quality is preferentially improved.

Therefore, in the communication apparatus 1 provided with a plurality of receiving circuits to cope with various communication modes, it is possible to reduce the power consumption in the receiving circuit while maintaining good reception quality without impairing the diversity effect.

In the above-described embodiment, the RSSI value is used to determine the reception status. However, the present invention is not limited to this, and the reception status may be determined based on the bit error rate. . That is, if the bit error rate to each receiving circuit is less than a predetermined threshold, it is determined that the receiving situation is good, the receiving circuit is selected for each slot, and the power supply to the non-selected receiving circuit is cut off. Is also good.

In the voice communication / low-speed data transmission mode, if the reception level is very high or the bit error rate is very low, diversity may not be performed. That is, step S in the flowchart of FIG.
Before the RSSI determination step of No. 6, it is determined whether the RSSI exceeds a second threshold value (for example, a very high value of about 40 dBu), and if the RSSI does not exceed the second threshold value,
Returning to the normal processing flow (steps S6 to S8), if the value exceeds the second threshold, diversity is not performed, and one of the receiving circuits having a high receiving level is fixedly selected to supply power. Then, the power supply to the other receiving circuit is cut off. In this case, the current supply to the non-selection circuit in the LM section is also cut off, so that the power consumption can be further reduced. In this case, since the RSSI measurement in step S5 is always performed, the process proceeds to step S6 when the RSSI does not exceed the second threshold.

In this embodiment, two receiving circuits are provided, but three or more receiving circuits may be provided. In addition, the specific value of the threshold set for the reception state determination is arbitrary, and it is needless to say that the threshold can be appropriately changed without departing from the gist of the present invention.

[0056]

According to the present invention, there is provided a communication apparatus having a plurality of receiving circuits and corresponding to a communication system including, for example, high-speed data transmission, voice communication, or low-speed data transmission.
If the reception condition is good, a first operation of selecting and operating one of the plurality of systems of reception circuits for each reception slot.
And the power supply to the non-selected receiving circuit is cut off in the slot section, so that the power consumption can be reduced. Further, when the reception condition is not good, switching to the second diversity system for selecting one of the detection outputs in the plurality of systems of reception circuits in units of reception symbols enables a reception operation with a high diversity effect to be performed. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication device 1.

FIG. 2 is a block diagram showing an internal configuration of a high frequency unit 2.

FIG. 3 is a flowchart illustrating a diversity switching process.

FIG. 4 is a diagram illustrating transmission / reception timing during high-speed data transmission.

FIG. 5 is a diagram showing transmission / reception timing when a slot-based diversity system is adopted during voice communication / low-speed data transmission.

FIG. 6 is a diagram illustrating a lapse of a reception level and a manner of switching a diversity system according to the lapse of a reception level during voice / low-speed data transmission.

FIG. 7 is a block diagram showing a transmission / reception circuit configuration of a conventional selection diversity system after detection.

FIG. 8 is a diagram showing transmission / reception timing in a conventional post-detection selection diversity system.

FIG. 9 is a block diagram showing a configuration of a transmission / reception circuit of a conventional antenna switching diversity system.

FIG. 10 is a diagram showing transmission / reception timing in a conventional antenna switching diversity system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication apparatus 2 High frequency part ANT1, ANT2 Antenna 21 Duplexer 22 Transmission circuit 23 Receiving circuit 24 Receiving circuit 25 Power supply control part 3 Digital processing part 4 Audio part 5 Display part 6 Operation part 7 Microphone 8 Speaker 9 Data I / O terminal

Claims (8)

[Claims] 1. A communication device comprising a plurality of systems of receiving circuits and performing a receiving process, comprising: determining means for determining a receiving state in the receiving circuit; and a receiving slot unit based on a result of the determination by the determining means. Either a first diversity scheme for selecting and operating any of the plurality of reception circuits or a second diversity scheme for selecting any detection output in the plurality of reception circuits for each received symbol A communication device, comprising: diversity switching means for switching power supply to each of the receiver circuits; and power supply control means for controlling power supply to each receiving circuit according to a diversity scheme. 2. The diversity switching means switches to the first diversity scheme when reception conditions are good, and switches to the second diversity scheme in other cases. 2. The communication apparatus according to claim 1, wherein when switching to the diversity mode, power supply to the non-selected receiving circuit is cut off in a receiving slot section. 3. The reception process includes a reception process corresponding to a high-speed data transmission and a reception process corresponding to a voice call or a low-speed data transmission. 3. The communication according to claim 1, wherein the communication system is switched to a diversity system, and when voice communication or low-speed data transmission is performed, the communication system is switched to one of the first and second diversity systems in accordance with a result of the determination by the determination unit. apparatus. 4. The receiving means according to claim 1, wherein said determining means determines that the receiving condition is good when the received electric field intensity in said receiving circuit exceeds a predetermined threshold value. The communication device according to any one of the above. 5. The receiving means according to claim 1, wherein said determining means determines that the receiving condition is good when a bit error rate of a detection output of said receiving circuit is smaller than a predetermined threshold value. The communication device according to any one of claims 1 to 3. 6. A communication method in a communication device including a plurality of systems of receiving circuits and performing a receiving process, comprising: a determining step of determining a receiving state in the receiving circuit; A first diversity scheme for selecting and operating any of the plurality of reception circuits in slot units, or a second diversity scheme for selecting any detection output in the plurality of reception circuits in reception symbol units A communication method, comprising: a diversity switching step of switching to any one of the following; and a power control step of controlling power supply to each receiving circuit in accordance with a diversity scheme. 7. In the diversity switching step, switching to the first diversity scheme is performed when reception conditions are good, and switching to the second diversity scheme otherwise. 7. The communication method according to claim 6, wherein power supply to a non-selected receiving circuit is cut off during a reception slot section when switching to the diversity method is performed. 8. The receiving process includes a receiving process corresponding to a high-speed data transmission and a receiving process corresponding to a voice call or a low-speed data transmission. The communication according to claim 6 or 7, wherein the communication method is switched to a diversity method, and is switched to one of the first and second diversity methods according to a result of the determination in the determination step during voice communication or low-speed data transmission. Method.