JPH03265314A - Transmission power control system - Google Patents

Abstract

PURPOSE:To reduce a hit rate due to waveform distortion or noise and to relieve the interference to another route by controlling the transmission power at a sender side in response to the variance of a reception level at a receiver side for each intermediate frequency IF signal. CONSTITUTION:A reception level detection section 22 uses the AGC voltage of each multi-carrier to decide that there is a necessity of control when the AGC voltage is lower than a preset level, and outputs control information. The control information at a station A being a sender is inputted to a DEM section 7 via an AGC section 6 or the like, where the information is separated from a signal of a main signal line. A transmission power control section 12 uses the separated control information to control the transmission level at an IF stage for each multi-carrier. Thus, the hit rate due to waveform distortion or noise is reduced and the interference to other route obtained by transmission power control is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to control of transmission power in fixed microwave communications, and in particular to transmission power control on a transmitting side in accordance with changes in reception level on the receiving side. Related to power control method.

[Prior Art] Conventional fixed microwave communication systems can only output a fixed value of transmission power within the range permitted by law. Therefore, during normal times, communications may be performed using a transmission power that is stronger than necessary, which may cause interference with other routes.

On the other hand, if the reception level is reduced due to fading or the like, it may not be possible to perform communication with sufficient transmission power to compensate for this.

In order to prevent such inconveniences, control has been considered in which the transmission level is kept low during normal times, and the transmission level is raised when the reception level decreases due to fading or the like. Such control can be expected to reduce momentary interruptions due to noise.

Conventionally announced transmission power control methods transfer information on the reception level to the other station and continuously control the transmission level so that the reception level becomes an appropriate value.

On the other hand, in recent years in the field of fixed microwave communications, multicarrier transmission, which can narrow the signal band and reduce instantaneous interruptions due to waveform distortion, has been widely adopted.

The configuration of a transmitter using this method uses multiple intermediate frequencies (I
F) The configuration is such that the signals are multiplexed, frequency-converted, and then amplified by a high-frequency amplifier and transmitted. However, an optimal transmission power control method for a system applying multicarrier transmission has not yet been proposed.

[Issue 8 to be solved by the invention] As mentioned above, multicarrier transmission is a technology that can reduce instantaneous interruptions due to waveform distortion by narrowing the signal band, and is a technology that is used in the field of fixed digital microwave communications. Widely used.

Transmission power control cannot reduce instantaneous interruptions caused by waveform distortion, but by increasing the transmission level when the reception level drops during fading, it can reduce the interruption rate due to noise and interfere with other routes. This is a technology that can reduce the

Therefore, by combining these techniques, −
It is considered that the instantaneous interruption rate of the layer can be reduced.

However, the characteristics of systems that apply multi-carrier transmission are: ■ Each multi-carrier has its own standby equipment and is independent in line; ■ Frequency conversion is performed after multiple intermediate frequency (IF) signals are combined. However, the signal may be amplified by a high frequency amplifier and then transmitted.

Therefore, for example, if transmission power control is performed at a high frequency stage where multiple multicarriers are combined, the transmission level of the multicarriers whose reception level has not decreased may also be increased, resulting in In some cases, the effect of reducing interference with other routes obtained by transmission power control may be diminished. In this case, a method of controlling each multicarrier is required.

In addition, in multicarrier transmission, one signal band is narrowed, and the frequency correlation with adjacent multicarriers is very high. It is also thought that the reception level has decreased considerably. In this case, when economical efficiency and stability of control are taken into consideration, it is considered advantageous to perform control for each of a plurality of multicarriers at once.

[Means for Solving the Problems 1] The present invention has been made to solve the above-mentioned problems, and these are achieved by the means described in the claims.

That is, the invention of claim 1 provides a plurality of intermediate frequencies (IF
) In a wireless communication system that performs communication by converting the frequency of a signal, amplifying it in a batch with a high-frequency amplifier for each system, and transmitting the signal, the transmission power on the transmitting side is multiplied by each IF according to changes in the reception level on the receiving side. This is a transmission power control method for controlling signals, and the invention according to claim 2 is a transmission power control method that performs frequency conversion on a plurality of intermediate frequency (IP) signals, amplifies them at once with a high frequency amplifier for each system, and transmits the signals. In a wireless communication system for performing communication, the transmission power control method collectively controls the transmission power on the transmitting side for each system in 11 stages according to a change in the reception level on the receiving side, and furthermore, the invention according to claim 3 is In the wireless communication method, communication is performed by converting the frequency of multiple intermediate frequency (IP) signals, amplifying them all at once with a high-frequency amplifier for each system, and transmitting the signals. This is a transmission power control method that arbitrarily controls the transmission power on the transmitting side according to the reception level on the receiving side by inserting a variable attenuator in the microwave stage that can be controlled.

[Function] In the invention of claim 1, on the receiving side, the reception level of each multicarrier is detected from the AGC voltage, and when the reception level becomes lower than a preset level, the transmission power is controlled to the maximum. It is determined that it is necessary to do so, and it is transmitted as control information to the transmitter on the transmitting side, for example, via a control line for the reverse direction (this line is usually used commonly by each radio channel).

On the other hand, on the transmitting side, the transmitter is configured to combine multiple intermediate frequency signals, convert the frequencies, and amplify them all at once using a high-frequency amplifier before transmitting, so the signals transferred from the receiving side Based on the control information, transmission power is controlled for each multicarrier at the IP stage before multiplexing.

Furthermore, in the invention of claim 2, the reception side detects the reception level of each multicarrier, and if one of them is lower than a predetermined level, for example,
Control information is issued, and the transmission side collectively controls transmission power for each system at the IP stage based on the control information.

Furthermore, in the invention of claim 3, the transmission power is controlled by controlling the variable attenuator of the microwave stage provided after the high frequency amplifier using control information.

[Embodiment] FIG. 1 is a block diagram showing a first embodiment of the present invention, in which (a) shows station A and (a) shows station B.

In the figure, 1.15 is an antenna, 2.16 is a duplexer, 3.17 is a receiving high frequency filter, 4.18 is a frequency conversion section, 5 and 19 are intermediate frequency amplification sections, and 6.20 is an A
GC Department, 7. 14. 21. 28 is the DEM department, 8.
22 is a reception level detection section, 9.23 is a high frequency filter for transmission, 10.24 is a power amplification section, 11.25 is a frequency conversion section, 12.26 is a transmission power control section, 13 and 27 are MO
It represents part D.

Next, the operation of the wireless communication device with the above configuration will be explained assuming that the transmitting side is station A and the receiving side is station B. First, a reception input signal received by the antenna 15 is converted to an intermediate frequency band (IP band) through a duplexer 16, a reception high frequency filter 17, and a frequency converter 18.

This received signal in the intermediate frequency band is then sent to the intermediate frequency amplification section 19 and the AGC section 2 subcommittee 0 to receive the DEM! ! 'Input to B. If the AGC voltage of each multicarrier is lower than a preset level, the reception level detection unit 22 determines that it is necessary to perform control, and outputs control information.

This control information is inserted into the control line by the DEM unit 28,
MOD section 27, transmission power control section 26, frequency conversion section 25
, the power amplifying section 24, the high-frequency transmitting filter 23, the duplexer 16, and the antenna 15, and then transferred to the A station side, which is the transmission source.

On the A station side, this control information is input to the DEM section 7 via the antenna 1, the duplexer 2, the reception high frequency filter 3, the frequency conversion section 4, the intermediate frequency amplification section 5, and the AGC section 6, and here, Separated from the main signal line. The transmission power control unit 11 controls the transmission level for each multicarrier in 11 stages based on the separated control information.

Next, a second example will be described.

This corresponds to the invention of claim 2. The configuration of the system in this invention is exactly the same as that in the first embodiment, but the control is different, so the operation will be explained using FIG. 1.

In the figure, when the transmitting side is 4 stations and the receiving side is station B, first, the received human signal received by the antenna 15 passes through the transmitting/receiving duplexer 16, the receiving high frequency filter 17, and the frequency converter 18, and then passes through the intermediate frequency band (IF band).

The received signal in the intermediate frequency band is then input to the DEM section through the intermediate frequency amplification section 19 and the AGC section 2 section 0. The reception level detection unit 22 determines that control is necessary based on the AGC voltage of each multicarrier if even one of them is lower than a preset level, and outputs control information.

This control information is inserted into the control line by the DEM unit 28,
MOD section 27, transmission power control 8B26, frequency conversion section 2
5, power amplification 19B24, high frequency filter for transmission 23,
The signal is transmitted via the duplexer 16 and the antenna 15 to the incoming station, which is the transmission source.

On the A station side, this control information is manually transmitted to the DEM unit 7 via the antenna 1, the duplexer 2, the high frequency reception filter 3, the frequency conversion unit 4, the intermediate frequency amplification unit 5, and the AGC unit 6, where it is Separated from the main signal line. Transmission power side #i9B
! 2 collectively controls a plurality of multicarriers for each system using the separated control information at 11 stages of transmission levels.

FIG. 2 is a block diagram showing a third embodiment of the present invention, which corresponds to the third embodiment of the invention.

In the figure, (a) shows four stations, (b) shows B station, 31.45 is an antenna, 32.46 is a duplexer,
33 and 47 are reception high frequency filters, 34.48 is a frequency conversion section, 35.49 is an intermediate frequency amplification section, 36.50 is an AGC section, 37.51 is a DEM section, 38.52 is a reception level detection section, 39 .53 is a high frequency filter for transmission, 40
, 54 is a power amplification section, 41.55 is a frequency conversion section, 42
, 56 is a transmission power control section, 43.57 is a MOD section, 44
, 58 represent a DEM section.

Next, the operation of the wireless communication device with the above configuration will be described assuming that there are four stations on the transmitting side and station B on the receiving side. First, the received human signal received by the antenna 45 is converted to an intermediate frequency band (IF band) through a duplexer 46, a high frequency receiving filter 47, and a frequency converter aB 48.

The received signal in the intermediate frequency band is then inputted to the DEM section via an intermediate frequency amplification section 49 and an AGC section 50. The reception level detection unit 52 determines that control is necessary based on the AGC voltage of each multicarrier if even one of them is lower than a preset level, and outputs control information. This control information is inserted into the control line by the DEM section 58, and passes through the MOD section 57, transmission power control section 56, frequency conversion section 55, power amplification section 54, high frequency filter for transmission 53, duplexer 46, and antenna 45. , is transferred to station A, which is the transmission source.

On the A station side, this control information is sent to the antenna 31, the transmitter/receiver duplexer 32, the receiving high frequency filter 33, and the frequency converter 34.
, intermediate frequency amplification section 35, AGC section 36, and DEM section 3.
7, where it is separated from the main signal line. The transmission power control unit 42 controls the transmission level at the high frequency stage using this separated control information.

[Effects of the Invention] As described above in detail, the following effects can be expected by using the control method according to the present invention for a method to which multicarrier transmission technology is applied.

That is, in the invention of claim 1, since the reception level is detected for each multicarrier and the transmission level is controlled for each multicarrier, it is possible to reduce the instantaneous interruption rate due to noise, and Since the transmission level for each multicarrier is individually controlled, the transmission level of each multicarrier will not increase unless the reception level becomes lower than a preset level.

Therefore, there is an advantage that the effect of reducing interference with other routes obtained by performing transmission power control can be maximized.

Further, in the inventions of claims 2 and 3, the ability to follow fast changes in the reception level during fading is good, and since the integrated control method is adopted, the control circuit portion can also be made smaller and easier. Moreover, there is an advantage that effective transmission power control can be expected.

Claims (1)

[Claims] 1. In a wireless communication system in which communication is performed by converting the frequency of a plurality of intermediate frequency signals, amplifying the signals in a batch with a high frequency amplifier for each system, and transmitting the signals, there is a problem in response to changes in the reception level on the receiving side. A transmission power control method that controls transmission power on the transmitting side for each intermediate frequency signal according to the transmission power. 2. In a wireless communication system that performs communication by converting the frequency of multiple intermediate frequency signals, amplifying them all at once using a high-frequency amplifier for each system, and transmitting the signals, the transmission on the transmitting side changes depending on the change in the reception level on the receiving side. A transmission power control method characterized by collectively controlling power for each system at an intermediate frequency stage. 3. In a wireless communication system that performs communication by converting the frequency of multiple intermediate frequency signals, amplifying them all at once using a high-frequency amplifier for each system, and transmitting the signals, a high-frequency signal that can be automatically controlled from the outside is installed after the high-frequency amplifier on the transmitting side. A transmission power control method characterized by controlling the transmission power on the transmitting side according to the reception level on the receiving side by inserting a variable attenuator in the stage.