JP2659275B2 - Wireless communication system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly to a wireless communication system in which the transmission power of a transmission device is controlled by the reception input level of an opposing receiving device.

[Conventional technology]

A conventional wireless communication system of this type will be described with reference to a block diagram of a wireless communication device shown in FIG. 4 and a transmission power control diagram shown in FIG.

The wireless communication apparatus shown in FIG. 4 performs mutual communication between the A station 40 and the B station 50 using a high-frequency carrier such as a microwave. The A station 40 includes a transmitting device (TX) 41 for transmitting communication signals of a plurality of channels, a diplexer 42 including a circulator and the like for separating a transmission signal and a reception signal,
An antenna 43 connected to the diplexer 2 for transmitting and receiving communication signals of different polarization such as cross polarization (for example, vertical (V) polarization and horizontal (H) polarization), and a receiving device (RX) for receiving a communication signal from the diplexer 42 ) 44 and a controller (TX-CONT) 45 for controlling the transmission power of the transmission device 41. Here, it is assumed that communication is performed with V polarization. Further, in addition to the device just described, communication equipment using different polarization (for example, H polarization) or using another antenna may be included. The communication signal transmitted from the antenna 43 is transmitted to the B station 50 via a wireless transmission path 46 using a radio wave as a propagation path. B station 50
Has a device similar to the A station 40, and includes a transmitting device (TX) 51,
It includes a diplexer 52, an antenna 53, and a receiving device (RX) 54. Also, of the communication signal received by the receiving device 54, the reception input level of a specific one channel is detected, and the detected level is transmitted to the station A using a predetermined one line of the wireless transmission line 46.
A controller 55 (RX-CONT) for sending to the controller 45 of 40 is included.

In this wireless communication device, as shown in FIG. 5, the transmission power (TX PWR) of the transmission device 41 is the reception input level RSL (Receiving Sig) output from the reception device 54 to the controller 55.
nal Level), control is performed between the Pmax level, which is the maximum output of the standard, and the Pmin level, which is the minimum output. When the reception input level RSL detected by the controller 55 is a predetermined reception input level limit point RSLth (normally, the RSLth level
The communication signal received at 50 is set to a level at which deterioration due to thermal noise starts to occur. If it is larger than the above, the controller 45 controls the transmitting device 41 down to maintain the transmission power at the Pmin level. When the reception input level RSL becomes lower than RSLth, UP control is performed to increase the transmission power to an appropriate value equal to or lower than the Pmax level.

[Problems to be solved by the invention]

In the above-described conventional wireless communication system, the transmission output control of the transmission device uses only the information on the reception input level of the communication signal received by the same channel of the opposing reception device as the control signal of the transmission power. Therefore, when there is an influence of interference by a signal of an adjacent channel, there is a disadvantage that deterioration of communication signal quality due to the influence cannot be reduced.

[Means for solving the problem]

A wireless communication system according to the present invention is a wireless communication system having a plurality of communication facilities including a transmitting device and a receiving device having a plurality of communication channels, and a specific channel input by a receiving device of a predetermined communication system equipment. Received input level information, received input level information of a channel adjacent to the specific channel input by a receiving device other than the predetermined communication system equipment, preset received input level limit value information, and preset interference Control means for controlling the transmission power of the specific channel of the transmission device of the predetermined communication system equipment from the signal limit value information, the control means, the average reception input level of the adjacent channel and the specific If the difference from the reception input level of the channel is larger than the interference signal limit information, or if the reception input level limit information is the reception level of the specific channel. It is greater than the input level information to increase the transmission power to a predetermined first value, if not corresponding to the above, wherein the decreasing the transmit power to a predetermined second value.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of a wireless communication device according to the present invention.

The A station 10 and the B station 20 are communication stations that communicate with each other by using a high frequency such as a microwave as a carrier, as in the conventional example. Station A
10 has two communication facilities. The first communication system equipment includes a transmitting device (TX) 1, a diplexer 2,
The B station includes an antenna 3 and a receiving device (RX) 4.
And V-polarized wave via the wireless transmission path 31. Channels for communication are channel 1 (CH1) to channel 7 (CH
7) It is assumed that there are four odd-numbered channels. Further, it has a communication facility for transmitting and receiving communication signals of the same channel with H polarization (not shown). The second communication system equipment includes a transmitting device (TX) 6, a diplexer 7, an antenna 8 and a receiving device (RX) 9, and communicates with the B station 20 via the radio transmission path 31 with V polarization. To communicate. Channels for communication include channel 2 (CH2) to channel 8 which are interleaved with the channel arrangement of the first communication system.
It is assumed that there are four even-numbered channels of (CH8).
Further, it has a communication facility for transmitting and receiving communication signals of the same channel with H polarization (not shown). Further, the transmitting device 1
And a controller (TX-CONT) 5 for controlling the transmission power for each channel.

The B station 20 also has two communication systems corresponding to the A station 10. The first communication system equipment includes a transmitting device (TX) 11, a diplexer 12, an antenna 13, and a receiving device (RX) 14. In addition, it has a communication facility corresponding to the A station 10 for transmitting and receiving communication signals of the same channel with H polarization (not shown). The second communication equipment is a transmitting device (TX) 16
, Diplexer 17, antenna 18 and receiver (RX) 19
And communicates with the A station 10 via the wireless transmission path 31 with the V polarization. Further, it has a communication facility for transmitting and receiving communication signals of the same channel with H polarization (not shown). Further, it has a controller (RX-CONT) 15 for transmitting a control signal generated from the reception signal of each channel of the reception devices 14 and 19. This control signal is transmitted to the controller 5 of the A station 10 through one predetermined line of the wireless transmission path 31. Except for the controllers 5 and 15, the components described above have the same functions as the components having the same names described in the description of the conventional example of FIG.

Here, the signal transmission characteristics of the transmission lines formed by the antennas 3 and 4 of the first communication system and the radio transmission line 31 and the transmission characteristics of the transmission lines formed by the antennas 8 and 18 and the radio transmission line 31 of the second communication system are described. The signal transmission characteristics are similar but not necessarily the same since both wireless transmission paths are close to each other and an antenna having almost the same characteristics is usually used. In particular, when fading occurs, the transmission characteristics vary from channel to channel and over time. Therefore, the level of an interference signal of another communication system mixed through an antenna or the like also changes.

The block diagram shown in FIG. 1 is an example for controlling the transmission power of the A station 10. In order to control the transmission power of the B station 20, the transmission signals of the transmission devices 14 and 19 of the B station 20 are controlled by the control signals generated from the reception signals obtained from the reception devices 4 and 9 of the A station 10. To control the transmission power.

FIG. 2 is a detailed block diagram of an example of the controller (RX-CONT) 15.

Here, a case where the transmission power of channel 2 (CH2) of transmitting apparatus 6 is controlled will be described. In this case, the channel 1 (CH1) and the channel 3 (CH3) of the transmission device 1 constitute adjacent channels. 21 is an average detector,
The average reception input level of channel 1 and channel 3 output from the reception device 14, that is, the average reception input level of the adjacent channel is detected. Reference numeral 22 denotes a level difference detector, and a receiving device 19
, The level difference between the reception input level of the channel 2 output from and the adjacent channel level (average reception input level), that is, the reception input level difference is detected. Then, when the average reception input level is large, level difference information whose output is positive is output. Reference numeral 23a denotes a comparator, which is a reception input level of channel 2 and a reception input limit point RSLt which is set in advance as a reception input level at which communication quality of a communication signal is deteriorated due to thermal noise.
Compared with h, if the reception input level of channel 2 is low, a logical signal “1” is output, and if it is high, a logical signal “0” is output. Reference numeral 23b denotes a comparator, which compares the level difference information with an interference signal limit point D / Uth set in advance as a limit point at which communication quality degradation of a communication signal due to adjacent channel signal interference occurs. When it is high, it outputs a logic signal "1", and when it is low, it outputs a logic signal "0". Reference numeral 24 denotes an OR circuit, which takes an OR gate of the comparators 23a and 23b and outputs a control signal "1" or "0".

Next, transmission power control in the embodiment of FIGS. 1 and 2 will be described with reference to FIGS. 3 (a) to 3 (f).

3 (a) to 3 (c) show the reception spectra of the channels 1, 2 and 3 at the output terminal of the receiving device 14 or 19. The shaded portion indicates the level of the interference signal, and the higher the level, the greater the amount of interference. FIG. 3A shows a case where the reception input levels of all the channels are the same level and are equal to or higher than the reception input limit point RSLth (here, the reception input signal level D of the channel 2 at the output terminal of the reception device 14 is equal to the reception input signal level DSL). The D / U ratio and the D / U ratio are set to 0 dB with respect to the interference signal level U. Hereinafter, the D / U ratio is shown in FIGS. D / U <0 when the reception input level of the channel 2 is low. In this case, as shown in FIG. 3 (d), DOWN control is performed on channel 2 to control the transmission power (TX PWR) to the level of Pmin. FIG. 3 (b) shows that the reception input level RSL of the channel 2 is lower than the reception input limit point RSLth due to attenuation due to rainfall or fading, but the reception input level of the channel 2 and the average reception input level of both adjacent channels 1 and 3 are shown. This is a case where the level difference D / U with the threshold value D / U is equal to or larger than the interference signal limit point D / Uth. At this time, as shown in FIG. 3 (e), UP control is performed according to the reception input level information, the transmission power of channel 2 is increased in the transmission device 6, and the reception input level of channel 2 of the reception device 19 is received. Keep at the input limit point RSLth. FIG. 3C shows a case where the reception input level RSL of the channel 2 is larger than the reception input limit point RSLth, but D / U is smaller than D / Uth. Here, as shown in FIG. 3 (f), UP control for increasing the transmission power of channel 2 is performed in the transmitting device 6 in accordance with the level difference information, and D / U is maintained at or above the interference signal limit point D / Uth.

In the above description, the amount of interference signal is estimated by the ratio between the reception input level of a specific communication channel and the average reception input level of an adjacent channel.

〔The invention's effect〕

As described above, the present invention compares the difference between the reception input level of the adjacent channel and the reception input level of the own channel in addition to the transmission power control based on the reception input level of the own channel which has been conventionally performed, and compares the comparison result. Estimate the interference signal level, and control the transmission power of the own channel based on the estimated signal level. Therefore, it is possible to reduce the deterioration of the communication quality due to the interference from the adjacent channel, and the effect is great for performing the communication of the appropriate quality.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a controller for creating a control signal, and FIGS. FIG. 4 is a diagram for explaining a transmission power control operation of the embodiment, FIG. 4 is a block diagram of a conventional embodiment, and FIG. 5 is an explanatory diagram of the transmission power control operation. 1,6,11,16,41,51 ... Transmission device, 2,7,12,17,42,52 ... Diplexer, 3,8,13,18,43,53 ... Antenna, 4,9,14,19 , 44,54
... Receiving device, 10,50 A station, 20,50 B station, 21 Average value detector, 22 Level difference detector, 23a, 23b Comparator, 24 OR
circuit.

Claims (2)

(57) [Claims] In a wireless communication system having a plurality of communication systems including a transmission device and a reception device having a plurality of communication channels, a reception input level of a specific channel input by a reception device of a predetermined communication system is provided. Information, reception input level information of a channel adjacent to the specific channel input by a receiving device other than the predetermined communication system equipment, predetermined reception input level limit information, and predetermined interference signal limit value And control means for controlling the transmission power of the specific channel of the transmission device of the predetermined communication system equipment from the information, the control means comprising: an average reception input level of the adjacent channel and a reception of the specific channel. If the difference from the input level is greater than the interference signal limit information, or if the reception input level limit information is the reception input level information of the specific channel. Ri said transmission power is increased to a predetermined first value is greater, the wireless communication system if it does not correspond to the above, wherein the decreasing the transmit power to a predetermined second value. 2. The control means according to claim 1, wherein said control means compares an average reception input level of said specific channel with an average value detector for detecting an average reception input level of said adjacent channel. A level difference detector that outputs level difference information whose output is positive when the input level is large, and compares the level difference information with the interference signal limit value information, and the level difference information is based on the interference signal limit value information. When the value is larger, the first comparator that outputs a logical signal “1” is compared with the reception input level information of the specific channel and the reception input level limit information, and the reception input level limit information is the specific input signal. A second comparator for outputting a logical signal "1" when the received input level information of the channel is larger than the received input level information, a logical circuit for calculating the logical sum of the outputs of the first and second comparators, When the logical signal output from the channel is "1", the transmission power of the specific channel is increased to a predetermined first value. When the logical signal is "0", the transmission power is increased to a predetermined second value. The wireless communication system according to claim 1, further comprising: a transmission power controller that reduces the transmission power to the transmission power.