JP2004096276A - Mobile communication system including relay station having function of controlling electric field strength around mobile station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system which limits a transmission output of a mobile station so that the electric field strength around the mobile station is limited within a predetermined range wherein no adverse effect is given on a medical electronic apparatus without the need for revamping the existing mobile station while continuing a mobile communication service. <P>SOLUTION: The mobile communication system adopting a cell system wherein the mobile station has a reception strength measurement means of a downlink radio wave from a base station and the base station has a communication channel control means of the mobile station, is provided with a relay station that has functions of relaying communication between the mobile station and the base station existing in a control area of the relay station and of limiting a transmission output of the mobile station so as to limit the electric field strength around the mobile station within a predetermined range at the same time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile communication system represented by a mobile phone.
[0002]
[Prior art]
Various problems have been pointed out as the number of mobile phone users has increased.
One of them is an adverse effect on medical electronic devices that are sensitive to external electromagnetic waves.
Medical institutions have many such devices.
Even outside of medical institutions, especially in the case of implantable cardiac pacemakers, it is not possible to identify the user by appearance, so the adverse effect of mobile phone transmission radio waves in public spaces such as inside public transportation is serious. Has been caught.
[0003]
In response to this problem, (a) a mobile station that has received a regulation signal automatically turns off or stops transmission (for example, see Patent Literature 1) or (b) issues from a medical electronic device or a relay station. A technique has been proposed in which a mobile station that detects a regulation signal automatically reduces power (for example, see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-11-308675 [Patent Document 2]
JP-A-11-308675 [0005]
[Problems to be solved by the invention]
In the prior art (a), a method of temporarily disabling the mobile communication service is used.
In addition to the function of a mobile phone that allows users to talk anywhere, the importance of mobile phones, which are evolving as mobile data communication terminals, is an overkill and loss of service.
In addition, the mobile communication service is a public service, and it is incompatible with the fact that a communication carrier is required to provide a communication service all over its service area.
[0006]
Further, in the conventional technique (b), it is possible to reduce the adverse effect on the medical electronic device without stopping the mobile communication service, but the existing mobile station does not have a means for detecting the restriction signal. For this reason, it is necessary to repair an existing mobile station or to wait for the generation of a mobile station compatible with the regulatory signal, and it is considered that a lot of cost or time is required before the effect is exhibited.
[0007]
Therefore, (Condition 1) while maintaining the mobile communication service, (Condition 2) the electric field intensity around the mobile station can be kept within a certain range that does not adversely affect the medical electronic device. A technology that can be applied to stations is required.
[0008]
[Means for Solving the Problems]
The present invention is intended to solve the problem by introducing a relay station having a function of controlling transmission output for a mobile station existing in a control area, which is interposed in communication between a base station and a mobile station. .
Controlling the transmission power of the mobile station by the base station is a technique that has already been implemented, and the relay station controls the transmission power of the mobile station so that the electric field intensity around the mobile station falls within a predetermined range. This can be done without modifying existing mobile stations.
There is a possibility that transmission to the base station cannot be performed simply by limiting the transmission output of the mobile station. Therefore, the relay station must be able to continue the communication service.
[0009]
As a standard in which the base station controls the transmission output of the mobile station, for example, there is a PDC digital mobile phone.
3.4.2.2 Transmission power control characteristics of RCR STD-27I "Digital car telephone system" issued by The Radio Industry Association of Japan (1) According to the mobile station, a class III mobile station with a maximum transmission power of 0.8 W is used. In this case, the transmission output can be controlled in the range of 0 dB to -20 dB in 4 dB steps. According to the configuration of 4.1.4.1.4 housekeeping bit, it is specified that the mobile station receives POW (mobile station transmission output value) on downlink RCH (housekeeping channel).
[0010]
Since it is a relay station introduced to reduce the transmission output of the mobile station, it is hereinafter referred to as a reduced relay station as needed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The configuration of the mobile communication system according to the present invention will be described with reference to FIG.
Generally, a plurality of mobile stations and base stations exist around one relay station.
FIG. 1 shows only one representative station.
14 indicates communication with a mobile station that does not pass through a relay station, and 15 indicates communication with another base station.
[0012]
The relay station 5 performs communication with the mobile station 8 using the communication means 1 with the mobile station.
Similarly, communication with the base station 13 is performed using the communication means 2 with the base station.
The relay station 5 controls the transmission output of the mobile station 8 existing in the control area 16 of the relay station using the transmission output control means 3 of the mobile station.
The relay station 5 alone or in cooperation with the base station 13 uses the communication channel control means 4 of the mobile station to perform control such as determination and switching of the communication channel used by the mobile station 8. When the mobile station 8 is in the control area of the relay station 5, a communication channel via the relay station 5 is used.
When the relay station 5 is mounted on a train and enters a mountain tunnel, communication with the surrounding base station 13 may become impossible. Therefore, a function of independently controlling the communication channel of the mobile station 8 is required. is there.
[0013]
The mobile station 8 performs communication with the relay station or the base station using the communication unit 6 with the relay station or the base station.
The mobile station 8 measures the reception intensity of the downlink radio wave from the relay station or the base station using the reception intensity measurement unit 7 for the downlink radio wave from the relay station or the base station, and notifies the relay station or the base station of the measurement.
The transmission output of the mobile station 8 changes according to an instruction using the transmission output control means 3 of the mobile station of the relay station 5.
[0014]
The base station 13 performs communication with the relay station 5 using the communication means 9 with the relay station.
The base station 13 performs communication 14 with the mobile station 8 without using the relay station 5 by using the communication means 10 with the mobile station.
The base station 13 performs communication 15 with surrounding base stations using the communication means 11 with another base station.
The communication means 9 with the relay station and the communication means 10 with the mobile station may be constituted by the same means or different means.
The communication means 11 with other base stations is generally different from the communication means 9 with the relay station and the communication means 10 with the mobile station.
The base station 13 uses the communication channel control means 12 of the mobile station to perform control such as determination and switching of the communication channel used by the mobile station.
[0015]
An embodiment of a procedure for controlling the electric field intensity around the mobile station will be described with reference to FIG.
[0016]
In procedure 1, an experiment is performed to determine an upper limit value E0 of the electric field intensity that does not adversely affect the medical electronic device.
Although the upper limit of the electric field strength is considered to vary depending on the manufacturer and model of the medical electronic device, it is appropriate to use the smallest upper limit.
[0017]
In procedure 2, an experiment is performed to determine the upper limit P0 of the transmission output of the mobile station so that the electric field strength around the mobile station does not exceed the upper limit E0 of the electric field strength obtained in procedure 1.
Depending on the manufacturer and model of the mobile station, and the relative position of the medical electronic device and the mobile station, the upper limit of the transmission output of this mobile station may vary, but under appropriate modeling of the actual use conditions, It is necessary to obtain a reasonable upper limit by conducting an experiment.
[0018]
In step 3, the target upper limit Ps of the transmission power of the mobile station is obtained by multiplying the upper limit P0 of the transmission output of the mobile station obtained in step 2 by an appropriate safety factor Fs.
[0019]
In procedure 4, a reduced force relay station is installed which instructs mobile stations existing in the control area to always indicate a transmission output that does not exceed the target upper limit Ps of the transmission output obtained in step 3.
[0020]
In step 5, the reduced relay station installed in step 4 is operated, and a mobile station existing in the control area is instructed to transmit power that does not exceed the target upper limit value Ps of the transmission power obtained in step 3 at all times. I do.
Since the transmission output of the mobile station does not exceed Ps, the electric field intensity around the mobile station does not exceed the upper limit E0 of the electric field intensity which does not adversely affect the medical electronic device, and does not adversely affect the medical electronic device. be able to.
[0021]
According to the present invention, it is possible to provide a mobile communication system capable of limiting the transmission output of the mobile station so that the electric field strength around the mobile station falls within a certain range while continuing the communication service. However, it is important to ensure that the area where the adverse effect on the medical electronic device is desired to be eliminated is included in the control area of the reduction station.
[0022]
An embodiment of a procedure for determining whether or not a mobile station exists in the control area of the reduced relay station will be described with reference to FIG.
If it is determined that the mobile station is in the control area of the reduced relay station, a communication channel via the reduced relay station is allocated.
[0023]
Although the reduced relay station performs communication channel control of the mobile station alone or in cooperation with another base station, it is easy to understand that the reduced relay station responds to the mobile station as a base station system in which the reduced relay station and the base station are combined.
FIG. 3 is shown from such a viewpoint.
[0024]
The mobile station creates a list of the received strengths of the received downlink radio waves of the reduced relay station or the base station and notifies the base station system of the list (FIG. 3-1).
[0025]
If the reduced relay station is not included in this list, the base station system determines that the mobile station is not in the control area of the reduced relay station (FIG. 3B-2 → 3).
[0026]
In the case where the reduced force relay station is included in this list, the loss Lr in the downstream section is determined by Lr = Pr / Sr from the reception strength Sr of the downlink wave from the reduced force relay station and the transmission output Pr of the downlink wave from the reduced force relay station. (Fig. 3-4).
The larger the value of Lr, the greater the loss.
[0027]
If the loss Lr in the downlink section is equal to or less than the predetermined level L0, the base station system determines that the mobile station is in the control area of the reduced relay station (FIG. 3-5 → 6).
If the loss Lr in the downlink section exceeds a predetermined level L0, the base station system determines that the mobile station is not in the control area of the reduced relay station (FIG. 3-5 → 3).
Since an appropriate value of L0 is considered to change depending on the situation where the reducing relay station is installed, it is desirable to experimentally determine the optimum value.
[0028]
FIG. 4 shows a change in the range determined as the control area of the reduced relay station depending on the magnitude of L0.
If L0 is too small, a necessary place is not included, and if L0 is too large, an unnecessary place is included.
When applied to the example of installing a reduction relay station on a railway vehicle, if L0 is too small, it may not be determined that the vehicle exists in the control area of the reduction relay station even inside the vehicle. This may cause a false determination as the control area of the reducing relay station.
In FIG. 4, 17 is a railcar, 18 is a reduction relay station, 19 is a mobile station, 20 is a base station, and 21 is a house near the station.
Reference numeral 22 denotes a control area of the reduced force relay station 18 when L0 is too small, 23 denotes a control area when L0 is appropriate, and 24 denotes a control area when L0 is too large.
[0029]
FIG. 5 shows a block diagram of one embodiment of the reducing relay station.
The transmission output control means 3 of the mobile station and the communication channel control means 4 of the mobile station are executed by control software built in the control circuit 25.
The communication means 1 with the mobile station comprises a mobile station antenna 26 and a mobile station transmitting / receiving circuit 27.
The communication means 2 with the base station is composed of a base station antenna 28 and a base station transmission / reception circuit 29.
Reference numeral 30 denotes a power supply circuit of the reduction relay station.
[0030]
【The invention's effect】
As described in detail above, according to the mobile communication system of the present invention, it is possible to keep the electric field strength around the mobile station within a certain range that does not adversely affect the medical electronic device while continuing the mobile communication service. it can.
In addition, since it can be applied to existing mobile stations, it will be possible to respond promptly only by installing a reducing relay station in a place where there is a concern about adverse effects on medical electronic equipment and modifying existing base stations around it. It is possible.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a mobile communication system according to the present invention;
FIG. 2 is a flowchart of an example of a procedure for controlling an electric field intensity around a mobile station according to an embodiment of the present invention;
FIG. 3 is a flowchart of an example of a procedure for determining that a mobile station is present in a control area of a reduced relay station according to an embodiment of the present invention;
FIG. 4 is a diagram showing a change in a range determined as a control area of a reduced force relay station depending on the magnitude of a parameter L0 in one example of a reduced force relay station according to an embodiment of the present invention;
FIG. 5 is a block diagram of an example of a reducing relay station according to an embodiment of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Communication means of relay station with mobile station 2 Communication means of relay station with base station 3 Transmission output control means of mobile station of relay station 4 Communication channel control means of relay station with mobile station 5 Relay station 6 of mobile station Means for communication with relay station or base station 7 Means for measuring reception intensity of downlink radio wave from relay station or base station of mobile station 8 Mobile station 9 Means of communication with base station relay station 10 Means of communication of base station with mobile station Reference Signs List 11 Communication means of base station with other base stations 12 Communication channel control means of base station mobile station 13 Base station 14 Communication with mobile station not passing through relay station 15 Communication with other base station 16 Control of relay station Area 17 Railway vehicle 18 Reducer relay station 19 Mobile station 20 Base station 21 House 22 near station 22 Control area 23 of reducer relay station 18 when L0 is too small Control area 24 when L0 is appropriate Control area 25 when 0 is too large Control circuit 26 for reduced power relay station Antenna 27 for mobile station of reduced power relay station Transmitter / receiver circuit 28 for mobile station of reduced power relay station Antenna 29 for base station of reduced power relay station Reduced power Transceiver circuit 30 for base station of relay station Power supply circuit for reduced power relay station

Claims (2)

A relay station (5) having communication means (1) with the mobile station, communication means (2) with the base station, transmission power control means (3) of the mobile station, and communication channel control means (4) of the mobile station; A mobile station (8) having a means for communicating with a relay station or base station (6), a means for measuring the reception intensity of a downlink radio wave from the relay station or base station, a communication means (9) with the relay station, and a mobile station. In the cellular mobile communication system, the communication system (10), the communication unit (11) with another base station, and the base station (13) having the communication channel control unit (12) of the mobile station are constituent elements. The transmission output of the mobile station (8) is configured to change according to the instruction of the relay station (5), and when the mobile station (8) exists in the control area of the relay station (5), the mobile station (8) The transmission and reception of the mobile station (8) is performed so that the surrounding electric field strength falls within a predetermined range. Mobile communication system and controls the. The mobile station (8) exists in the control area of the relay station (5) based on the measurement value of the reception intensity measuring means (7) of the downlink radio wave from the relay station or the base station and the transmission output of the relay station (5). The mobile communication system according to claim 1, wherein it is determined whether or not to perform.

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