JPH0616594B2 - Transmission power control method - Google Patents

Description

Detailed Description [Overview] The transmission power of the transmitting station is set to a value that is sufficient to maintain sufficient line quality in normal times, and when the line loss of the line increases, Responsive to the fact that the number of spectrum component signal values of a predetermined number of predetermined frequencies has dropped below a predetermined value, the transmission power of the transmission station is sufficient to maintain normal reception at the reception station even with the above line loss. The transmission power is increased by a certain value.

[Industrial application field]

The present invention relates to a transmission power control method, and more specifically, to transmission power control for lowering power consumption and the like, for the transmission power control for a low power consumption, etc. The present invention relates to a transmission power control method using the predetermined number of spectrum component signal values of a predetermined frequency at the time of abnormality.

In a wireless communication network such as digital multiplex wireless communication, when transmitting desired information from a transmitting side to a receiving side,
The information will be sent on radio waves. In order for the reception side to receive the radio wave successfully, the radio wave must be radiated from the transmission side to the reception side with the transmission power required for the reception side. Then, in the transmission, the transmission power must be determined in consideration of not only the transmission capacity of the transmission / reception system but also the state of the transmission medium. In addition, it is important to consider the state of other transmission / reception systems regardless of whether they are existing or not in the area where the transmission / reception system is constructed, in order to prepare various wireless communication systems in that area as they should be. It is a matter.

[Conventional technology]

A conventional digital multiplex wireless communication system is constructed as shown in FIG. The transmission signal modulated by the modulator 2 on the transmission side is transmitted from the IF band to the RF by the transmitter 4.
The frequency is converted to a band. The output signal of the transmitter 4 is power-amplified by the power amplifier 14 and radiated from the transmitting antenna 16 to the receiving antenna 30. The signal received by the receiving antenna 30 is frequency-converted from the RF band to the IF band by the receiver 32, then AGC-amplified by the AGC amplifier 34, and used for reproduction of the transmission signal by the demodulator 36.

The transmission power in such a transmission / reception system is the AG of the reception side.
Even when the gain adjusting function of the C amplifier 34 approaches the upper limit thereof, the radio wave having a sufficient intensity to maintain the line quality can be radiated from the transmitting antenna 16 to a predetermined value. , It used to be set.

[Problems to be solved by the invention]

However, the setting of the transmission power as described above can be affirmed from the viewpoint of maintaining the line quality, but from the viewpoint of power saving, the transmission power is unnecessarily large for a long time. It means that the information is transmitted by electric power. This is because the transmission power set as described above has a large line loss (mainly a loss due to fading) that lasts only about 5 to 10 hours a year, so that such a large transmission power is used in other time zones. This is because it is determined that the desired line quality is maintained in the time zone in which a large line loss occurs as described above, although the above is not required.

Further, with the above-mentioned large transmission power, there is no problem if there is no other transmission / reception system in the area where the transmission / reception system is installed, but if it is not so, the influence occurs, which is inconvenient.

The present invention was created in view of such problems, and it is an object of the present invention to provide a transmission power control method for effectively utilizing radio wave propagation characteristics and performing communication under as low a transmission power as possible. To aim.

[Means for solving problems]

FIG. 1 shows the principle configuration of the present invention. In the figure, 2 is a transmitter of the transmitting station 4, 6 is a transmission power changing means for changing the transmission power level, and 7 is a transmission level control means. Reference numerals 10 and 12 are transmission / reception antennas. Reference numeral 13 is connected to the receiver 18 of the receiving station 16, and in a normal radio wave propagation state, the spectrum component signal values at the frequencies separated by a predetermined frequency in the reception band are respectively determined in advance. First transmission power control information indicating that the first value is taken with respect to the spectrum component signal reference value, or each of the spectrum component signal values in the reception band in the abnormal radio wave propagation state corresponds to the above beforehand. It is a transmission power control information output means for outputting second transmission power control information indicating that it has a value different from the first value with respect to the determined spectrum component signal reference value.

Then, the transmission level control means 7 responding to the second transmission power control information sent from the transmission power control information output means 13 to the transmitter via the system of the wireless communication system.
Is a transmission power larger than the transmission power at the time of the first transmission power control information by a value sufficient for compensating for the line loss distribution that has caused the second transmission power control information. The present invention is configured so that the data can be output from the control unit 6.

[Work]

At the time of communication with a relatively small line loss, the transmission level control means 7 is received from the transmission power control information output means 13 of the reception station 16 through the transmitter 2, the transmission / reception antennas 12 and 10 and the receiver 18 of the transmission station 4. The first transmission power control information is fed back to.

The transmission level control means 7 that has received the first transmission power control information sets the transmission power level of the transmission station 4 to the transmission power level corresponding to the first transmission power control information. To control.

As a result, radio waves with low transmission power are radiated from the transmission / reception antenna 10 of the transmission station 4 toward the transmission / reception antenna 12 of the reception station 16, and required communication is performed.

When the line loss of the communication line increases, the spectrum component signal value of the predetermined number of predetermined frequencies within the reception band received by the receiving station 16 becomes different from the corresponding predetermined spectrum component signal reference value. The second transmission power control information is generated from the transmission power control information output means 13, and is input to the transmission level control means 7 from the transmission / reception antenna 12 through the transmission / reception antenna 10 and the receiver 18.

The transmission level control means 7 changes the set level of the transmission power changing means 6 so as to raise the transmission power level in response to the second transmission power control information.

As the line loss decreases, the first transmission power control information is sent from the receiving station 16 to the transmission level control means 7 in the same manner as described above. Therefore, the setting level of the transmission power changing means 6 is: Can be converted to lower transmit power levels.

Since the communication time with a large transmission power as described above is relatively short even in a year, it is useful for saving the transmission power. Further, a significant reduction in transmission power can reduce the degree of communication interference to other systems, which is useful for increasing the distribution of radio waves to that area.

〔Example〕

FIG. 2 shows an embodiment of the present invention. In this figure, 4
₁ , 16 ₁ are transmitting / receiving stations, and 2 18 are transmitters and receivers of the transmitting / receiving stations, respectively. 8 is a transmission level control circuit (first
In the example of FIG. 7), 14 is a reception level detection circuit (example of 13 of FIG. 1). Although these circuits 8 and 14 are shown only for one transmitting / receiving station for the sake of clarity, they are provided for each station.

The configurations of the transmitter 2 and the transmission level control circuit 8 are shown in FIG. The transmitter 2 has an IF amplifier 2 ₁ , a mixer 2 ₂ ,
Transmitter local oscillator 2 ₃ , variable attenuator 2 ₄ and RF amplifier 2
₅ (where between f _If , f _TL and f _{T in} the figure, | f _T −
f _TL | = _If )). The variable attenuator 2 ₄ shows a configuration example of the transmission power changing means 6 in FIG. 1, which gives an RF signal an attenuation amount determined according to an analog voltage value and R
This is for inputting to the F amplifier ₂₅ , that is, for changing the transmission power level. The analog voltage is output from the transmission level control circuit 8. The circuit 8 outputs a signal output from the command signal regeneration circuit 20 connected to the output of the AGC amplifier 18 ₅ of the receiver 18, for example, a transmission power control command. An analog signal for decreasing the attenuation amount according to the high level signal "1" at a certain time, for example, an analog signal for eliminating the attenuation amount, and an analog signal for increasing the attenuation amount according to the low level signal "0" when not present. Is output.

The structure of the receiver 18 is shown in FIG. In the figure, the receiver 18 includes an RF amplifier 18 ₁ , a mixer ₂ , a receiving local oscillator 18 ₃ and an IF band pass filter (IFBR).
F) 18 ₄ and AGC amplifier 18 ₅ . The AGC amplifier 18 ₅ has an output 1 and an output 2, the output 1 is connected to a demodulator (not shown), and the output 2 is connected to the reception level detection circuit 14 and the command signal reproduction circuit 20. The reception level detection circuit 14 detects the reception level and outputs a transmission power control command, and the output signal thereof is transmitted to the opposite station via the transmitter 2 of the own station.

The details of the reception level detection circuit 14 are, as shown in FIG. 5, IF amplifiers 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄ , attenuators 14 ₅ , 14 ₆ and a center band in the reception band and its Three band pass filters 14 ₇ , 14 ₈ , 14 ₉ having pass bands in the upper and lower bands, and detectors 14 ₁₀ , 14 ₁₁ , 14
₁₂ and the detectors 14 ₁₀ , 14 ₁₁ and 14 on one input, respectively.
DC amplifiers 14 ₁₃ , 14 ₁₄ and 14 ₁₅ which are supplied with ₁₂ outputs and different reference voltages r ₁ , r ₂ and r ₃ are applied to the other inputs to output binary output levels, and each DC amplifier 1
NAND circuit 1 which receives the binary outputs of 4 ₁₃ , 14 ₁₄ and 14 ₁₅
4 ₁₆ and.

The transmission power control mode under the above configuration will be described below.

Now, the transmission level control circuit 8 of the transmitting / receiving stations 4 ₁ and 16 ₁
When the line loss between the transceiver stations 4 ₁ and 16 ₁ is below a predetermined value, from the antenna 10 or 12 at a relatively low transmission power level sufficient to make the reception level above the predetermined value. It is assumed that the radio wave is set to be emitted to the opposite station. This is produced as follows.

In such a setting, the IF input signal of the frequency f _If to the transmitter 2 is amplified by the IF amplifier 2 ₁ and is mixed by the mixer 2 ₂
Input to, RF signals are frequency converted in the mixer 2 ₂ which receives a local oscillation signal of a frequency f _T from the transmission local oscillator 2 ₃ together with its signal is changed to _{(| = f If | f T} -f TL). This RF signal is amplified by the RF amplifier ₂₅ , and its amplitude is attenuated by the analog signal from the transmission level control circuit 8 so that the transmission power level supplied to the antenna 10 becomes the above-mentioned level. _Five
Is input to. Thus, a radio wave whose transmission power level is the above level is radiated toward the opposite station to perform the required communication.

It is received by the antenna 12 of the opposite station 16 _1, RF amplifier 1
The RF signal amplified by 8 ₁ is input to the mixer 18 ₂ ,
The RF signal receives the local oscillation signal of the frequency f _RL = f _TL from the reception local oscillator 18 ₃ together with the RF signal.
The frequency is converted into an IF signal of frequency f _If in ₂ and input to the AGC amplifier 18 ₅ via the IF band pass filter 18 ₄ . The IF signal amplified and output to the output 1 is input to a demodulator (not shown) and used for reproducing the transmission signal.

The IF signal output to the output 2 of the AGC amplifier 18 ₅ is I
It is amplified by the F amplifiers 14 ₁ , 14 ₂ , 14 ₃ , and 14 ₄ .
The amplified IF signals pass through the corresponding bandpass filters 14 ₇ , 14 ₈ and 14 ₉ and the corresponding detectors 14 ₁₀ and 1 respectively.
4 _11, the spectrum component signals in the band corresponding been detected in 14 ₁₂ are respectively output. However, the output IF signals of the IF amplifiers 14 ₂ and 14 ₄ are respectively attenuated by a predetermined amount by the attenuators 14 ₅ and 14 ₆ before being input to the corresponding band pass filters 14 ₇ and 14 ₉ , respectively. It is inputted to the band pass filters 14 ₇ and 14 ₉ .

The signals of the detectors 14 ₁₀ , 14 ₁₁ and 14 ₁₂ are compared with the preset reference voltages r ₁ , r ₂ and r _{3 in the} corresponding comparators 14 ₁₃ , 14 ₁₄ and 14 ₁₅ . While the line loss is below the above-mentioned predetermined value, the detectors 14 ₁₀ and 1
The signals 4 ₁₁ and 14 ₁₂ are generated so as to maintain the transmission power level described above with reference to the corresponding reference voltage, and accordingly, the comparison circuits 14 ₁₃ , 14 ₁₄ and 14 ₁₅ output "1". Alternatively, the signals E _L , E _M , and E _{H of} “0” are output. Therefore, the NAND circuit 14 ₁₆ receiving these signals E _L , E _M , and E _H outputs a “0” or “1” transmission power control command. This command is transmitted to the opposite station 4 ₁ via the transmitter 2 of the own station 16 ₁ and the antenna 12, and is given to the transmission level control circuit 8 via the antenna 10 and the receiver 18 of the opposite station 4 ₁ . Thus, the signal from the circuit 8 maintains the transmission power level at a level capable of maintaining the line quality.

In such a transmission / reception state, if the line loss increases due to changes in fading, weather, etc., the signal level radiated at the set transmission power level as described above and received by the opposite station decreases by that amount.

Therefore, as described above, the detectors 14 ₁₀ , 14 ₁₁ , 14 ₁₂
The spectrum component signal level output from the device also decreases accordingly. The decrease is due to the fact that it is different in the reception band, and one or two or three comparison circuits 14 ₁₃ , 1
A signal of “0” (or “1”) is output from 4 ₁₄ and 14 ₁₅ . As a result, the NAND circuit 14 ₁₆ outputs “1”.
The transmission power control command of is output. This command is also transmitted to the opposite station in the same manner as described above. In this case, the signal level given from the receiver 18 to the transmission level control circuit 8 is a high level "1". To the variable attenuator 2 ₄ from the transmission level control circuit 8, allowed to reduce the amount of attenuation therein, for example, an analog signal that does not give attenuation is generated. As a result, the transmission power level of the radio wave radiated from the antenna 10 is raised to a level capable of maintaining the line quality, and the opposite station can receive the radio wave at a reception level capable of maintaining the line quality at a desired value.

The reduction of the transmission power level at the time of line loss recovery is
It occurs in the feedback control manner described above with the loss of the transmit power control command of "1".

It should be noted that, in the above-mentioned embodiment, the transmission power is controlled by 2
Although the example in which the binary information “0” or “1” is used has been shown, the transmission power control may be performed in another binary information format, for example, the multilevel adjustment format may be changed. The change in transmission power may be brought about by adjusting the variable power amplifier. Also, the reduction of the transmission power level mentioned above may occur with a certain time delay.

〔The invention's effect〕

As described above, according to the present invention, according to the conventional knowledge, the time required to transmit under a large transmission power is only a relatively small time even in a year. According to the method of the present invention in which the transmission power is increased only to maintain the line quality, the transmission power can be significantly reduced, and the degree of communication interference to other systems can be reduced and the radio wave distribution to the area can be increased. it can.

[Brief description of drawings]

1 is a block diagram of the principle of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a block diagram of a transmitter and a transmission level control circuit, FIG. 4 is a block diagram of a receiver, FIG. 5 is a reception level detection circuit diagram, and FIG. 6 is a configuration diagram of a conventional digital multiplex wireless communication system. In FIGS. 1 to 5, 2 is a transmitter, 4 is a transmission station (transmission / reception station 4 ₁ ), 6 is transmission power changing means (variable attenuator 2 ₄ ), 7 is transmission level control means (transmission level control circuit). 8), 10 and 12 are transmission / reception antennas, 13 is transmission power control information output means (reception level detection circuit 14), 16 is a reception station (transmission / reception station 16 ₁ ), and 18 is a receiver.

Claims (1)

[Claims] 1. A radio communication system for amplifying a transmission signal by a transmitter (2) of a transmission station (4) and radiating the amplified signal toward an opposite reception station (16) to perform required communication. 4) is provided in the transmitter (2),
While the transmission power changing means (6) and the transmission level control means (7) for changing the transmission power are provided, the receiving station (16) is connected to the receiver (18) of the receiving station (16) and receives in a normal radio wave propagation state. A first indicating that each of the spectrum component signal values at each of the frequencies separated by the predetermined frequency in the band takes a first value with respect to a corresponding predetermined spectrum component signal reference value Of the transmission power control information, or in the abnormal radio wave propagation state, each of the spectrum component signal values in the reception band has a value different from the first value with respect to the corresponding predetermined spectrum component signal reference value. A transmission power control information output means (13) for outputting second transmission power control information indicating that the transmission power control information is output is provided. Wherein said transmission level control means responsive to the second transmission power control information sent to the transmitter via a system wireless communication system (7),
Than the transmission power at the time of the first transmission power control information,
A transmission power control system characterized in that the transmission power changing means (6) outputs a transmission power large enough to compensate for the line loss distribution that has generated the second transmission power control information.