JPH0998109A - Communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily control the transmission output of output difference between transmission channels or the like in simple configuration. SOLUTION: Transmission and reception are time-divided at different timing and communication is performed while setting transmission and reception frequencies at the same frequency. At such a time, the intensity of a received signal is detected at transmission timing by a detecting means 23 and corresponding to that detected intensity, a communication control part 21 controls the transmission output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device suitable for application to, for example, digital transmission of digital data by TDMA.

[0002]

2. Description of the Related Art In a radio telephone device or the like, it is necessary to accurately control the transmission output within a specified range. That is,
In the case of a wireless telephone device such as a cellular system, the transmission output is limited so that the same transmission frequency can be used in areas that are separated by a predetermined distance, and the efficiency of frequency use is improved.

FIG. 3 is a diagram showing an example of a conventional transmission output control circuit. A transmission signal obtained at an input terminal 51 is amplified by two stages of amplifiers 52 and 53 which are final output amplification stages, and then, The signal is supplied to the output terminal 55 via the demultiplexer 54, and the transmission signal obtained at the output terminal 55 is supplied to the antenna for wireless transmission.

Here, the demultiplexer 54 demultiplexes a part of the transmission signal and supplies it to the detector 56 for detection. Then, the level data detected by the detector 56 is supplied to the power supply circuit 57 which is a power supply source for determining the amplification factors of the amplifiers 52 and 53. Then, in the power supply circuit 57, based on the supplied level data, the amplifiers 52 and 53 are
The gain of each amplifier 52, 53 is controlled by changing the power supply (current value, etc.) supplied to the amplifiers.

By controlling in this way, the gains of the amplifiers 52 and 53 are controlled based on the level of the transmission signal,
The output of the transmission signal can be controlled within a certain range.

Further, FIG. 4 shows an example of a conventional transmission output control circuit according to another method. A transmission signal obtained at an input terminal 61 is converted into a final output amplification stage by a two-stage amplifier 6.
After amplification at 2, 63, it is supplied to the antenna and wirelessly transmitted.

Then, the output current of the power supply circuit 65 for generating the power supply to the final stage amplifier 63 is detected by the current detection circuit 66, and is supplied to the previous stage amplifier 62 according to the detected current value. Power supply circuit 6 for generating power
7 to control the output current and the gain of the amplifier 62.

By controlling in this way, according to the current value of the power source proportional to the output level of the amplifier 63 at the final stage,
The gain of the amplifier 62 is controlled so that the output of the transmission signal can be controlled within a certain range.

[0009]

By adopting the configuration shown in FIG. 3 or the configuration shown in FIG. 4, the transmission output can be kept within a certain range even if the power supply voltage fluctuates or the temperature of the environment in which it is used changes. However, when a plurality of channels to be transmitted (that is, transmission frequencies) are prepared, the difference in transmission output between the channels cannot be corrected. That is, generally, there is a slight deviation in the transmission output between the channels to be transmitted, but control for correcting this deviation has not been conventionally performed.

However, in a communication system such as a wireless telephone, it is preferable that there be no such deviation in transmission output between channels.

In view of the above point, the present invention has an object to make it possible to favorably control the transmission output with a simple structure.

[0012]

In order to solve this problem, according to the present invention, transmission and reception are time-divisionally performed at different timings, and a transmission frequency and a reception frequency are communicated at the same frequency. In the device, the intensity of the received signal is detected at the transmission timing, and the transmission output is controlled according to the detected intensity.

According to this structure, the strength of the transmission signal leaking from the transmission system circuit to the reception system circuit at the transmission timing is
The reception intensity detection means included in the reception system circuit detects the transmission output. By operating the reception intensity detection means, which originally operates only at the reception timing, also at the transmission timing, the transmission output is detected and the transmission output is controlled. You can

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The present embodiment is applied to a terminal device of a digital cellular radio telephone system in which voice data converted into digital data is transmitted. The communication system between the base station and the terminal device is as follows: A TDMA method (Time Division Multi) for intermittently transmitting and receiving burst data having a slot configuration at periodic timings
(iplex access method: time division multiple access method)
The system to which is applied. In the case of this TDMA method, the same frequency is used as the transmission frequency and the reception frequency for communication performed at the same time between the base station and one terminal device.

FIG. 1 is a diagram showing the configuration of a mobile phone, which is the terminal device of this example, in which transmission data (digital data) obtained at an input terminal 11 is supplied to a modulator 12. Here, the transmission data obtained at the input terminal 11 is considered to be burst data already transmitted only at the transmission timing in the processing circuit (not shown) in the preceding stage. Then, the modulator 12 generates a two-channel transmission signal of I component and Q component from the supplied transmission data (bit data). In this case, the modulator 12 is supplied with transmission output control data from the communication control unit 21 to be described later, and the output levels of the I component and Q component transmission signals are changed based on this control data. . That is, for example, when the standard output level is 100%, the output level is 8
It is set so that it can be changed in steps of 2.5% from 0% to 120%.

Then, the transmission signal of the two channels of the I component and the Q component output from the modulator 12 is transmitted to the transmission processing circuit 13.
And quadrature modulates the I component and the Q component with a carrier wave of a predetermined frequency. Then, the quadrature-modulated transmission signal is frequency-converted into a predetermined transmission frequency in the transmission processing circuit 13,
The frequency-converted transmission signal is subjected to transmission processing such as amplification and band limitation. In this case, the frequency conversion to the transmission frequency is performed by mixing the frequency signal output from the frequency synthesizer 22 configured by the PLL circuit (phase locked loop circuit) with the transmission signal. The output frequency of the frequency synthesizer 22 is set to the communication control unit 21.
This frequency synthesizer 2 is decided based on the control of
By controlling the output frequency of 2, the transmission frequency and the reception frequency (in the present example, the transmission frequency and the reception frequency are the same) are determined. As the transmission / reception frequency, a channel (frequency) used for communication is instructed by, for example, a control signal transmitted from the base station side.

Then, the transmission signal output from the transmission processing circuit 13 is transmitted to the transmission side contact 14a of the antenna changeover switch 14.
To supply. In the antenna changeover switch 14, switching of the movable contact 14m is performed under the control of the communication control unit 21, and is connected to the transmission side contact 14a at the transmission timing and connected to the reception side contact 14b at the reception timing. Done. The communication timing controlled by the communication control unit 21 is set to be, for example, a timing synchronized with the frame period instructed by the control signal received from the base station or the like.

By controlling the changeover switch 14 in this way, the transmission side contact 14 is provided during the period when the transmission signal is obtained.
a is connected to the movable contact 14m, and the transmission signal output from the transmission processing circuit 13 is transmitted to the movable contact 14m of the changeover switch 14.
This antenna 1 is supplied to the antenna 15 connected to
It is wirelessly transmitted from 5.

Next, the reception system will be described. The reception side contact 14b of the antenna changeover switch 14 is connected to the reception processing circuit 16, and the signal received by the antenna 15 at the reception timing is supplied to the reception processing circuit 16. . Then, the reception processing circuit 16 mixes the received signal with the frequency signal output from the frequency synthesizer 22, converts the mixed signal into an intermediate frequency signal of a predetermined frequency, and amplifies the intermediate frequency signal.
Received signal output terminal 1 after receiving processing such as band limitation
7 and demodulates the data transmitted by the demodulator (not shown) connected to the reception signal output terminal 17.

The intermediate frequency signal obtained by the reception processing circuit 16 is supplied to the reception electric field strength detection circuit 23, and the electric field strength (RSSI) of the reception signal is detected by the detection circuit 23. Then, the detected received electric field strength signal (voltage value)
Is supplied to the analog / digital converter 24 to be converted into digital data. Then, the converted received electric field strength data is supplied to the communication control unit 21.

Then, the communication control section 21 judges whether or not the reception has been successfully performed based on the received data of the reception field intensity, and it can be determined that the reception field intensity has been successfully received at a predetermined level or higher. If the received electric field strength is below a predetermined level and it is difficult to continue the communication, a handover process for switching to communication with another base station (adjacent another base (When there is a station) or disconnecting the line (when there is no other base station that can be switched).

In the present embodiment, the reception processing circuit 16 is operated even during the transmission timing period so that the reception electric field strength detection circuit 23 detects the reception electric field strength, and the analog / analog
The communication control unit 21 determines the detection data output by the digital converter 24 at that time. Then, based on the level of the received electric field strength determined by the communication control unit 21 at this time, the control data for setting the output levels of the transmission signals of the I component and the Q component from the modulator 12 for transmission is set to the modulator 12 Supply to.

In this case, in this example, the communication control unit 21
A reference value for the received electric field strength detected at the time of transmission is set in advance, and control is performed to set the output level of the transmission signal so that the detected received electric field strength is approximately equal to this reference value. Is done. As the control at this time,
The change in the received electric field strength detected based on the change in the transmission channel (frequency) is corrected. That is, when the transmission channel is set to a certain channel, the value of the received electric field strength at the transmission timing at that time is determined, the difference from the reference value is determined, and the difference is kept within a predetermined range. , Set the output level.

Further, the output level is corrected as needed even when the received electric field strength changes at the transmission timing due to factors such as a change in power supply voltage, a change over time, and a use environment (change in temperature).

Next, the operation when performing communication with the mobile phone of this example will be described. First, the mobile phone of this example is TD
Since communication is performed with a base station or the like by the MA method, transmission and reception are performed in a time division manner at different timings. That is, as for the transmission timing, as shown in FIG. 2A, burst data t ₁₁ in which one slot has a period of 625 μsec in a 5 msec cycle,
t _12, t ₁₃ ‥‥ is transmitted based on the control of the communication control unit 21. In this case, the burst data of each slot is arranged by compressing voice data for 5 msec.

The reception timing is shown in FIG.
As shown in B of FIG. 3, burst data t ₂₁ , t _22, ... Of which one slot is 625 μsec in a period different from the period in which this transmission slot is arranged (here, a timing shifted by 2.5 msec from the transmission slot). Is received under the control of the communication control unit 21. Also for the burst data of this reception slot, voice data for 5 msec or the like is compressed and arranged. Up to this point, the communication control is based on the TDMA method. Originally, the transmission processing circuit 13 is operated only during the transmission processing of the transmission slot, and the reception processing circuit 16 is operated.
For the above, the receiving slot is operated only during the receiving process.

Here, in this example, when the transmission output is judged by the communication control unit 21, the reception processing circuit 16, the reception electric field strength detection circuit 23, the analog / digital converter is also used for the transmission processing of the transmission slot. 24 is operated to determine the received electric field strength at that time. That is,
2B, timings t ₃₁ , t ₃₂ , t _33, ...
.. (this timing t ₃₁ , t ₃₂ , t _33, ... Is the same as the timing t ₁₁ , t ₁₂ , t _13, ... At which the transmission slot is transmitted), and the reception electric field strength is determined. Note that the reception process at this time does not necessarily have to be continuously performed for one slot period (here, 625 μsec), and may be performed at least for a period during which the reception electric field strength can be determined.

Then, a process for controlling the output level of the transmission signal is performed based on the received electric field strength determined during this transmission period.

By controlling the transmission output in this way, the strength of the transmission signal leaking from the transmission processing circuit 13 to the reception processing circuit 16 via the antenna changeover switch 14 at the transmission timing is detected by the reception electric field strength detection circuit 23. As a result, the transmission output can be detected accurately. That is, the antenna changeover switch 14 includes the transmitting side contact 1
4a and the receiving side contact 14b are not directly connected, but there is a leaking signal as indicated by the broken line arrow, and the level is sufficient for detection by the reception electric field strength detection circuit 23. Signal is obtained. Therefore, by controlling the transmission output based on the received electric field strength detected at this time,
It is possible to control the transmission power accurately.

In this case, in this example, since the transmission output is judged by the communication control unit 21 which controls the transmission channel, it is possible to judge the change in the transmission output due to the change in the transmission channel, and the transmission output for each transmission channel. The deviation of can be corrected. Further, it is possible to detect the received electric field strength at the time of transmission, even when the transmission output changes due to factors such as a change in power supply voltage, a change over time, and a use environment (such as a change in temperature).

The circuits 23 and 24 for detecting the received electric field strength are circuits necessary for communication control, and the communication control unit 21 performs a transmission output control process based on the received electric field strength during the transmission period. The transmission output control according to the present embodiment can be performed only by making the above setting, and the circuit can be realized with a simple configuration without requiring a dedicated circuit for detecting the transmission output.

In the case of correcting the difference in the transmission output for each transmission channel, when transmitting on all channels, even if the reception electric field strength at the time of transmission is not detected, for example, some representative values are obtained. The received electric field strength is detected only when transmitting a channel, the difference between the detected values between channels at that time is interpolated, and the output during transmission on the other channels is estimated. Based on the estimated value, each channel is estimated. May be controlled.

Further, in the above-mentioned embodiment, the output levels of the transmission data I and Q of the two channels generated in the modulator are changed based on the control data of the transmission output. May be changed. For example, the gain of the transmission amplifier in the transmission processing circuit is
It may be changed based on the transmission output control data.

Further, although the above-mentioned embodiment is applied to the terminal device of the radio telephone system in which the digital data is transmitted by the TDMA method, other communication methods can be used as long as the transmission method and the reception method are alternately performed in a time division manner. It can also be applied to a communication type communication device. Also, regarding the transmission signal, although the method of quadrature modulating the 2-channel transmission signal of the I component and the Q component generated from the data to be transmitted, it can be applied to a communication device that is transmitted by another modulation method.

[0036]

According to the present invention, the intensity of the transmission signal leaking from the transmission system circuit to the reception system circuit at the transmission timing is detected by the reception intensity detecting means included in the reception system circuit to control the transmission output. It is possible to satisfactorily control the transmission output within a predetermined range with a simple configuration without providing a dedicated circuit for detecting the output.

In this case, the transmission signal generation means changes the output level of the signal to be transmitted according to the reception intensity to control the transmission output, thereby eliminating the need for separately providing an amplifying means for controlling the transmission output. , It becomes possible to control the transmission output.

Further, the transmission output between the transmission frequencies (transmission channels) is set by determining the change in the intensity due to the change in the transmission frequency and setting the appropriate transmission output by the transmission output control means for each transmission frequency. It becomes possible to correct the deviation of.

[Brief description of drawings]

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

FIG. 2 is a timing chart showing transmission / reception timing of an embodiment.

FIG. 3 is a configuration diagram showing an example of a conventional transmission output control circuit.

FIG. 4 is a configuration diagram showing another example of a conventional transmission output control circuit.

[Explanation of symbols]

 11 transmission data input terminal 12 modulator 13 transmission processing circuit 14 antenna changeover switch 15 antenna 16 reception processing circuit 17 reception signal output terminal 21 communication control section 22 frequency synthesizer 23 reception electric field strength detection circuit 24 analog / digital converter

Claims (3)

[Claims] 1. A detection device for detecting the intensity of a received signal in a communication device which performs transmission and reception at different timings in a time division manner and communicates a transmission frequency and a reception frequency at the same frequency, and the detection means. A communication device comprising: a discriminating unit that discriminates the intensity detected at the transmission timing by the unit; and a transmission output control unit that controls the transmission output according to the intensity discriminated by the discriminating unit. 2. The communication device according to claim 1, wherein the transmission signal generating means controls the transmission output by changing the output level of the transmission signal according to the intensity judged by the judging means. 3. The discriminating means determines a change in intensity due to a change in transmission frequency, and the transmission output control means sets an appropriate transmission output for each transmission frequency.
The communication device as described.