JPH0923176A - Diversity device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the circuit scale, size and price of this diversity device by selecting one of outputs from plural power amplifiers and and of monitor outputs from respective couplers connected to plural transmitting/receiving antennas and controlling a transmitting output only by a single power control circuit. SOLUTION: A transmitting antenna selecting switch(SW) 118 selects one of power amplifiers 119 to 12 based upon a control signal 114a to transmit a signal obtained by frequency-converting a modulated transmitting signal through a transmitting circuit 117. The signal 114a indicates an antenna system having a maximum receiving level to allow SWs 118, 127 to select one of outputs from respective amplifiers 119 to 122 and one of outputs from respective monitoring couplers 123 to 126. An automatic power control circuit 128 controls the transmitting output of the circuit 117 based upon the output of the SW 127 and controls the transmitting output of a specified antenna at a prescribed value. Consequently the transmitting output 15 controlled by the single circuit 128 and the circuit scale, size and price of the whole system can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity apparatus for improving the reception level deterioration at the base station side due to fading caused by the movement of a mobile unit in mobile communication for time division communication.

[0002]

2. Description of the Related Art In mobile communication, there is a drawback in that the reception level is deteriorated due to fading caused by the movement of a mobile station and the communication quality is deteriorated. As means for solving this drawback, for example, Japanese Patent Application Laid-Open No. 2-1922
A diversity technique as described in Japanese Patent Publication No. 30 (H04B7 / 04) is conventionally known. In this conventional technique, transmission / reception is performed by the same radio frequency, transmission / reception switching is performed by dividing time, and an antenna selected by diversity after detection at reception is used as a transmission antenna. Configured as shown.

In FIG. 4, signals received by antennas 1 and 2 which are spatially separated are input to receiving circuits 5 and 6 via circulators 3 and 4, respectively. The outputs of the reception circuits 5 and 6 are input to the demodulation circuits 7 and 8, respectively, and part of them are input to the control circuit 9. The control circuit 9 measures the output signal levels of the receiving circuits 5 and 6 and compares them. As a result of the comparison, a control signal for selecting the demodulation circuit connected to the signal branch having the higher signal level is output to the switch circuit 10. The output of the selected demodulation circuit is input to the digital-analog conversion circuit 11, and the received analog signal is output to the output terminal 12.

On the other hand, the analog signal input to the input terminal 13 is converted into a digital signal by the analog-digital conversion circuit 14. This digital signal is modulated by the modulator 15. The modulated signal is input to the transmission circuit 16 that performs frequency conversion, amplification, etc., and is input to the switch circuit 17. At this time, as described above, the control circuit 9 stores the selection branch selected in the immediately preceding reception, and outputs the control signal for selecting the antenna belonging to this selection branch to the switch circuit 17. Therefore, the transmission signal is transmitted from the antenna selected by the switch circuit 10.

By the way, when the above-mentioned conventional technique is applied to, for example, a base station of a mobile phone, the transmission signal is amplified by the transmission circuit 16 of one system, and then the antenna 1 is transmitted via the switch circuit 17. Since it is configured to be transmitted from any one of the two, in consideration of the loss of the switch circuit, a power amplifier with a considerably large output is required to obtain a predetermined output. Such a large output power amplifier is not only very expensive, but also has a problem in that it consumes a large amount of power and generates a large amount of heat. In addition, the switch circuit 17
However, there is a problem that it is necessary to switch such a large power with good linearity, and such a switch circuit is also expensive. Further, there is a serious problem that transmission becomes impossible if the power amplifier fails.

[0006] Therefore, in order to improve the problems of the prior art, the applicant of the present application has filed Japanese Patent Application No. 7-125249. This application transmits / receives at the same radio frequency, switches transmission / reception by dividing time, and uses an antenna selected by diversity after detection at reception as a transmitting antenna, as shown in FIG. Is composed of.

FIG. 2 is based on a 4-branch post-detection selective diversity system having four antennas.

In FIG. 2, 101, 102, 103,
Reference numerals 104 denote transmission / reception dual-purpose antennas, which are spatially spaced apart from each other. The transmission / reception changeover switch 105 is a transmission / reception changeover unit that is switched at a predetermined timing by a transmission / reception changeover signal sent from a system control circuit (not shown). , 106, 107, 108. 109, 110, 111, and 112 are antennas 101 to 104 via transmission / reception changeover switches 105 to 108.
Is a receiver circuit connected to, and performs frequency conversion, band limitation, amplification, etc. of the signal input from each antenna. The signals received by each of the receiving circuits 109 to 112 are sent to the receiving antenna selection switch 113 for diversity reception, the receiving level (RSSI) is measured, and the measurement result is sent to the RSSI comparing circuit 114. To be done. In the RSSI comparison circuit 114, the RS from each reception circuit
The SI is compared, a control signal for selecting the antenna with the highest reception level is sent to the reception antenna selection switch 113, and the changeover switch 113 is controlled. As a result, of the antennas 101 to 104, the signal received by the antenna with the highest reception level is sent to the demodulation circuit 115,
Demodulation of the digital signal is performed, and in this manner, post-detection selection diversity is performed.

On the other hand, the transmission signal is subjected to predetermined modulation in the modulation circuit 116, frequency conversion is performed in the transmission circuit 117, and then sent to the transmission antenna selection switch 118. By the way, a power amplifier 119 is provided to each of the antennas 101 to 104 via the transmission / reception changeover switches 105 to 108.
The power amplifiers 119 to 122 are connected to the transmission antenna selection switch 118. The transmitting antenna selection switch 118 is the receiving antenna selection switch 11
Similar to 3, the switching control is performed by the control signal output from the RSSI comparison circuit, and therefore the transmission signal output from the transmission circuit 117 is connected to the antenna of the power amplifiers 119 to 122 having the maximum reception level. It is amplified and transmitted depending on what is present.

The power amplifiers that are not selected by the transmission antenna selection switch 118 during the transmission period are controlled to be inoperative.

FIG. 3 is a block diagram of a conventional example in which the transmitting section of FIG. 2 is further described in detail.

In FIG. 3, power amplifiers 119 and 12 are provided.
Outputs 0, 121 and 122 are couplers 123 and 12 respectively.
4, 125, 126.

Couplers 123, 124, 125, 126
Is inserted to monitor the output of each power amplifier,
The next-stage auto power control circuit 129,
Monitor outputs are input to 130, 131, and 132.

Such couplers 123 to 126 are usually formed on the dielectric substrate by microstrip lines,
It is composed of a main line inserted in each transmission system in series, a sub line arranged in parallel with the main line with a certain gap and coupled at high frequencies, and a terminating resistor. The coupling degree of this coupler is usually selected to be about 15 to 20 dB.

After that, the auto power control circuit 12
In Nos. 9 to 132, the transmission output level sent from each antenna is stably controlled to be a predetermined value, and in some cases, the transmission output is gradually changed according to an instruction from a system control circuit (not shown). Generate a control signal.

Further, an auto power control circuit 12 is provided.
9 to 132 outputs are transmission antenna selection changeover switch 11
8 and the variable attenuators 134, 135, 13 inserted in the preceding stages of the power amplifiers 119 to 122, respectively.
6 and 137 are input to the variable attenuator.
A feedback loop is formed for each transmission system of each power amplifier by a method such as controlling the amount of data, and the above transmission output control is performed.

[0017]

The above-described FIG.
In the invention shown in (1), the same number of auto power control circuits and variable attenuators as the power amplifiers are required.

Therefore, a control signal supplied from the system control circuit (not shown) to the auto power control circuit is also required for each auto power amplifier circuit.

Therefore, in the above technique, the number of parts and the number of signal wirings such as control signals are increased, and the circuit scale is large and complicated.

[0020]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art by transmitting on a single frequency,
In a diversity device that performs reception and reception, and performs diversity transmission and reception with at least two or more transmission and reception antennas that are spatially separated,
The reception level of each antenna detected by the plurality of reception circuits is compared with the transmission / reception switching means switched by the reception switching signal, the plurality of reception circuits respectively connected to the plurality of antennas via the transmission / reception switching means. Comparing circuit, a plurality of power amplifiers respectively connected to the plurality of antennas via the transmission / reception switching means, and a transmission signal to any one of the plurality of power amplifiers based on a comparison result of the comparing circuit. Transmitting antenna selection switch means for transmitting, a plurality of couplers arranged for each of the plurality of power amplifier outputs to monitor the outputs, and a monitor output of the coupler is input and any one of the monitor outputs is selected and switched. A changeover switch for outputting and a monitor output from the changeover switch output are supplied, and the plurality of power amplifier outputs output the plurality of antennas. O for controlling the transmission output to be sent via a - Topawa - control - is characterized in that it has a Le circuit.

[0021]

According to the present invention, diversity reception is performed, the transmission antenna switch is switched and controlled based on the reception level detected by the reception circuit, and transmission is performed by one of the plurality of power amplifiers provided in each antenna. The signal is amplified and transmitted.

The output of each power amplifier is switched by a changeover switch for selecting and outputting one of the monitor outputs of the couplers arranged in the subsequent stages, and by a single power control circuit. Transmission output control is performed.

Therefore, the circuit scale such as the number of parts and the number of signal wirings can be reduced, and the size and cost can be reduced.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment according to the present invention. The same components as those of the conventional technique shown in FIGS. 2 and 3 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the modulated transmission signal input from the terminal 116a is frequency-converted by the transmission circuit 117 and then transmitted to the transmission antenna selection switch 118.

A control signal 1 output from the RSSI comparison circuit 114 is sent to the transmission antenna selection changeover switch 118.
Therefore, the transmission signal output from the transmission circuit is amplified and transmitted by one of the power amplifiers 119 to 122, which is connected to the antenna having the maximum reception level. Be seen.

The power amplifier not selected by the transmission antenna selection switch 118 during the transmission period is controlled to be inoperative.

The power amplifiers 119 to 122 are provided with couplers 123 to 126 for monitoring the outputs, respectively.

In the couplers 123 to 126, the transmission signals output from the power amplifiers 119 to 122 by the coupler lines which are arranged in parallel with the main lines of the respective transmission systems with a certain gap and are coupled in high frequency. To monitor.

The monitor outputs of the couplers 123 to 126 are input to the changeover switch 127. The changeover control signal 114a supplied to this changeover switch is the RSSI.
Any one which is supplied from the comparison circuit 114 and is currently in operation
The monitor output from the transmission system of the system power amplifier is selected.

Thereafter, by utilizing this monitor output, the auto power control circuit 128 stably controls the transmission output level sent from the antenna to a predetermined value, or in some cases, an instruction from a system control circuit (not shown). Generates a control signal for changing the transmission output stepwise.

Further, the automatic power control circuit 12
The eight outputs are input to the transmission circuit 117, and a feedback loop of the transmission unit is formed by a method such as controlling the attenuator amount of the internal variable attenuator, and the above transmission output control is performed.

[0033]

As described above, the diversity device according to the present invention has a plurality of couplers arranged respectively for a plurality of power amplifier outputs for amplifying a transmission signal provided in each of a plurality of transmitting / receiving antennas. The transmission output is controlled by a single power control circuit, which is switched by a changeover switch that selects any one of the monitor outputs.

Therefore, it is possible to reduce the number of parts required for the auto power control circuit and the variable attenuator, the number of signal wirings such as control signals, and to reduce the circuit scale. Price realization can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a conventional technique.

FIG. 3 is a block diagram showing a conventional technique.

FIG. 4 is a block diagram showing a conventional technique.

[Explanation of symbols]

101, 102, 103, 104 Transmitting / receiving antennas 105, 106, 107, 108 Transmission / reception switching means (selection switch) 109, 110, 111, 112 Reception circuit 113 Reception antenna selection switch 114 RSSI comparison circuit 115 Demodulation circuit 116 Modulation circuit 117 Transmission Circuit 118 Transmission antenna selection switch 119, 120, 121, 122 Power amplifier 123, 124, 125, 126 Coupler 127 Monitor output selection switch 128, 129, 130, 131, 132 Auto power control circuit 134, 135, 136, 137 Variable Attenuator -

Claims (1)

[Claims] 1. A transmission / reception switching signal in a diversity apparatus for transmitting / receiving at a single frequency and performing diversity transmission / reception with at least two or more transmitting / receiving antennas spatially separated from each other. Transmission / reception switching means, a plurality of reception circuits respectively connected to the plurality of antennas via the transmission / reception switching means, and a comparison circuit for comparing reception levels of the respective antennas detected by the plurality of reception circuits. A plurality of power amplifiers respectively connected to the plurality of antennas via the transmission / reception switching means, and a transmission for transmitting a transmission signal to any one of the plurality of power amplifiers based on a comparison result of the comparison circuit. Antenna selection switch means, a coupler for monitoring the outputs of the plurality of power amplifiers, and selective switching of the coupler monitor outputs Switching switch, an auto power control circuit for receiving a monitor output from the change switch, and generating a control signal for controlling a transmission output, and the output of the auto power control circuit is A diversity device characterized in that it is input to a stage before a transmitting antenna selecting means to control a transmitting output.