JPH08316871A - Radio transmission power interrupt system - Google Patents

Abstract

PURPOSE: To prevent adverse effect onto a human body by automatically interrupting a transmission output when the human body is highly possible of exposure of an electromagnetic wave in the 2-way radio communication system conducting communication with a high frequency signal of a microwave band or over. CONSTITUTION: The system is made up of an antenna 11 having a directivity in a same direction both for transmission and reception, a reception circuit section 2, a transmission power control circuit section 3 monitoring a reception signal level and interrupting transmission power when the reception level is lower than a threshold level and a transmission circuit section 1 controlled by the transmission power control circuit section 3. The transmission power control circuit section 3 stops a control signal for a short time for each prescribed period decided in advance during control of transmission power interruption to restart the transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way wireless communication system, and more particularly to a wireless communication system using a high frequency signal in the microwave band or above which may adversely affect the human body.

[0002]

2. Description of the Related Art Conventionally, it has been reported that electromagnetic waves, particularly microwaves and higher-frequency electromagnetic waves, adversely affect the human body. In recent years, particularly in the field of wireless communication, mobile communication, satellite communication and wireless LAN communication have been reported. The frequency utilization of higher frequencies is increasing mainly because of the limitation of frequency resources. Furthermore, since the number of mobile communication terminals, satellite communication terminals, and wireless LAN communication terminals is rapidly increasing and the usage patterns thereof are approaching those of home electric appliances, the possibility that the human body will be irradiated by the electromagnetic waves is dramatically increasing.

In such an environment, various electric devices are regulated to radiate electromagnetic waves as seen in legal regulations such as VCCI. However, these are generally against electromagnetic waves radiated from the main body of electric devices. The regulation is mainly, and regarding the electromagnetic waves directly radiated from the antenna, from a practical point of view, the regulation value is looser than the regulation for the electromagnetic waves radiated from the electric device body or the like.

On the other hand, conventionally, the antenna is often set in a place where it is difficult for a person to come close to it, and no particular measures are taken. Or, it was only dealt with by providing a function to call attention by an alarm light emission or an alarm sound near the antenna during transmission.

Further, the invention disclosed in Japanese Patent Laid-Open No. 1-318437 branches and monitors the transmission signal of its own station in order to avoid the influence of the radio signal on the human body, and stops the output at a certain level or less. There is also.

[0006]

However, the above-mentioned conventional countermeasures such as cautionary notes and warnings have no effect on a careless person, a person who ignores it even if he / she knows it, and has no adverse effect on the human body. However, there is a possibility that the person in charge of manufacturing such a radio device may be sued as a PL problem.

Further, when an antenna having a directivity is used, even if the human body is positioned in the same direction as the directivity of the antenna even if the distance between the antenna and the human body is considerably large due to the directivity. There was a problem that the electromagnetic radiation dose did not decrease so much.

Further, since the invention of Japanese Patent Laid-Open No. 1-318437 detects a transmission signal, it has a problem that detection becomes difficult when a human body or the like is separated from the antenna.

An object of the present invention is to automatically perform automatic transmission when the human body is likely to be irradiated with the electromagnetic wave in the two-way wireless communication system for communicating by using the microwave or the radio wave having a shorter wavelength. The purpose of the present invention is to provide a method that can significantly reduce the chance of adversely affecting the human body by cutting off the transmission output.

[0010]

The present invention relates to a wireless communication system for bidirectionally communicating between first and second wireless devices having the same structure by using a high frequency signal in a microwave band or higher. The first wireless device receives a reception signal from the opposite second wireless device, and the reception level drops below a predetermined value,
And first control means for cutting off the transmission power by detecting that the decrease continues for a predetermined time or more, and after cutting off the transmission power, stop cutting off the transmission power for a short period of time at a predetermined cycle, In the meantime, when the reception level exceeds the predetermined value, the second transmission means continuously transmits the transmission power to the opposite station, and the wireless transmission power cutoff method.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a radio transmitter / receiver to which the radio transmission power cutoff method of the present invention is applied, and shows a method using a shared antenna for transmission and reception.

FIG. 2 shows a specific configuration of the transmission power control circuit section shown in FIG.

FIG. 3 is a timing chart showing the relationship between the fluctuation of the received signal level and the control signal for cutting off the transmission power of the wireless handset of the present invention when the opposing radio does not have the function of the present invention. It is shown in the chart.

FIG. 4 is a specific timing chart showing the relationship between the fluctuation of the received signal level and the control signal for cutting off the transmission power when the opposing radio has the function of the present invention.

FIG. 5 is a diagram for concretely explaining the recovery sequence from the transmission power cutoff control state in the case where the opposite radio has the function of the present invention.

The present invention, as shown in FIG.
A transmission circuit unit 1 for inputting 1 and outputting a transmission signal 102 radiated from the antenna as a radio signal;
Directional coupler 101 for inputting and distributing as a transmission / reception signal 103 only to the antenna direction, a transmission / reception shared antenna 11 for transmitting the transmission / reception signal 103 as a radio wave, and a signal received by the transmission / reception shared antenna 11 as a transmission / reception signal 103. The directional coupler 10 that distributes as the received signal 104 only to the receiving circuit unit 2, the receiving circuit unit 2 that inputs the receiving signal 104 and outputs the receiving signal 105 and outputs the input level signal 107, and the input level signal The transmission power control circuit unit 3 receives 107 and outputs a transmission power cutoff control signal 106.

The detailed functions and operations will be described below.

FIG. 2 shows the specific fairness of the transmission power control circuit 3 in FIG. 1, and the configuration of the opposite station opposite to the present invention in FIG. 3 does not have the configuration of the present invention, and the reception level is The control sequence in the case of using a wireless device that does not block transmission even when the power consumption decreases is shown in a timing chart with the horizontal axis as time.

The transmission power control circuit 3 inputs an input level signal 10 indicating the reception input level of the signal received by the reception circuit section 2.

In the reception level drop detecting section 301, a predetermined level is set as a threshold value as shown in FIG. 3 due to deterioration of received signal power which occurs when the directivity of the antenna is blocked by a human body or the like (state 1 in FIG. 5). When the input level signal 107 is equal to or less than the threshold value and has passed a predetermined fixed time (time represented by x in FIG. 3) or more, the transmission power cutoff control signal 304 is output.

Here, when the opposite station does not have the configuration of the present invention and uses a radio that does not cut off transmission even when the reception level is lowered, the interval timer 302 and the transmission power cutoff control mask are used. The unit 303 does not function, the transmission power cutoff control 304 is output as it is as 106, and the transmission circuit unit cuts off the transmission signal 102. (State 2 in FIG. 5) Further, when the input level signal 107 of the received signal is restored to the threshold value or more due to the movement of the human body or the like, a predetermined fixed time (time represented by z in FIG. 3) or more After confirming the normal input level, transmit power cutoff control signal 30
4 is stopped, the transmission signal 102 of the transmission circuit unit 1
Restore. Note that the time x represented by y in FIG.
Since the time is shorter than the time represented by z and z, the control output and stop are not performed.

FIG. 4 shows a control sequence in the case where the opposite station has the configuration of the present invention and uses a radio device that cuts off transmission when the reception level decreases, with a timing chart with the horizontal axis representing time.

In this case as well, the control for outputting the transmission power cutoff control signal 304 is similar to the control shown in FIG. 3, but as a result, similar control occurs also in the opposite station.
Even if the spatial transmission path is cleared by the movement of the human body or the like, the radios of both stations will remain in the transmission power cutoff state. (State 3 in FIG. 5) A sequence for recovering from this state will be described below.

In FIG. 2, the reception level drop detecting section 301 is shown.
When the transmission power cutoff control signal 304 is output from the interval counter 302, the transmission power cutoff control signal 304 is output.
, The mask signal 30 is generated for each interval time of time i represented by j for the time represented by j as shown in FIG.
5 is output.

The times of i and j are set to appropriate values in advance. When the mask signal 305 is output, the transmission power cutoff control mask section 303 masks the input transmission power cutoff control signal 304 with the mask signal 305 to stop the transmission power cutoff control signal 106, thereby increasing the transmission signal power. Restore. (State 4 in FIG. 5) Furthermore, since the received signal is input to the radio device of the opposite station, the transmission power cutoff control is stopped and the transmission is restarted similarly to the radio device of the own station. At this time, if the spatial transmission path is cleared by the movement of the human body or the like, the level of the reception signal 104 of the own station returns to normal, and the recovery from the transmission power cutoff control state is completed. (State 5 in FIG. 5) Although the present embodiment has been described by taking the case where the common antenna for transmission and reception is used as an example, even if the transmission antenna and the reception antenna are constituted by independent structures, directivity in the same direction is maintained. If it has, the effect of the present invention can be expected sufficiently.

As described above, according to the present invention, in a two-way radio communication system in which high-frequency signals of microwaves or higher are used for communication, radio waves with shorter wavelengths have stronger straightness, so that radio waves transmitted from both directions are transmitted through the transmission path. When reaching the antenna of the partner station through the same space, the human body receives the strongest electromagnetic radiation when blocking the space, and the larger the space is, the higher the received signal level on the receiving side becomes. It is the one that utilizes the decrease.

[0028]

As described above, according to the wireless transmission power cutoff method of the present invention, by monitoring the received signal level, the human body is aware of the possibility of being irradiated with electromagnetic waves, and the transmission power is cut off so that the human body is cut off. It is possible to minimize the adverse effect on the environment, etc., and when the influence of electromagnetic wave irradiation disappears due to the movement of the human body, etc., it is automatically restored, so it is very easy to operate and economically. There is an effect that the PL problem can be dealt with at a minimum cost.

In addition, the received power may be significantly reduced due to obstacles other than the human body, such as rainfall, but when communication is difficult in this way, the transmission power is cut off so that useless radio waves are not radiated. It also has the effect of being completed.

[Brief description of drawings]

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

FIG. 2 is a block diagram specifically illustrating a transmission power control circuit unit in FIG.

FIG. 3 is a timing chart specifically showing the relationship between the fluctuation of the received signal level and the transmission power cutoff control signal when the opposing radio does not have the function of the present invention.

FIG. 4 is a timing chart specifically showing the relationship between the fluctuation of the received signal level and the transmission power cutoff control signal when the opposing radio has the function of the present invention.

FIG. 5 is a diagram for concretely explaining a recovery sequence from the transmission power cutoff control state step by step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 transmitter circuit unit 2 receiver circuit unit 3 transmitter power control circuit unit 10 directional coupler 11 transmitter / receiver shared antenna 101, 102 transmitter signal 103 transmitter / receiver signal 104, 105 receiver signal 107 input level signal 106 transmitter power cutoff control signal 301 receiver level drop Detection unit 302 Interval timer 303 Transmission power cutoff control mask unit 305 Mask signal 304 Transmission power cutoff control signal

Claims (3)

[Claims] 1. In a wireless communication system in which a high-frequency signal in a microwave band or higher is used to bidirectionally communicate between first and second wireless devices having the same configuration, the first wireless device faces each other. A first control means that receives a reception signal from the second wireless device, detects that the reception level drops below a predetermined value, and that the drop continues for a predetermined time or longer, and cuts off transmission power. Then, after the transmission power is cut off, the transmission power is stopped for a short period of time at each predetermined cycle, and if the reception level exceeds the predetermined value during that period, the transmission power is continuously transmitted to the opposite station. And a second control means for transmitting to the wireless transmission power cutoff method. 2. When the third radio device facing the first or second radio device does not include the first and second control means, the first or second radio device is the 2. The wireless transmission power cutoff method according to claim 1, wherein after the transmission power is cut off by the first control means, the cutoff of the transmission power is stopped when the reception level from the third wireless device exceeds the predetermined value. 3. The first and second wireless devices include a transmission circuit section that cuts off transmission power by a control signal, an antenna that transmits the transmission signal, and a reception circuit that amplifies a reception signal received from the antenna. And a transmission power control section that receives the received signal and outputs a control signal to the transmission circuit section based on the first, second, and third control means. The wireless transmission power cutoff method according to Item 1 or 2.