Note: Descriptions are shown in the official language in which they were submitted.
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Mobile Communication System
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to the inhibition or
restriction of use of a mobile communication terminal, such
as a pager (a selective call receiver), a portable radio
device, a telephone or a cordless telephone, in a mobile
communication system wherein radio communication is per-
formed between a base station and such a mobile communica-
tion terminal.
2. DESCRIPTION OF THE PRIOR ART
According to a mobile communication technique whereby
radio communication is performed between a mobile communica-
tion terminal, such as a pager (a selective call receiver),
a portable radio device, a telephone or a cordless tele-
phone, and a base station that provides a communication
service for such a mobile communication terminal, a cont-
roller for locking operations is provided for the mobile
communication terminal, and a control signal can be trans-
mitted from outside to the controller to inhibit or limit
the use of the mobile communication terminal. "The res-
triction of the use" defines that only communication with a
specific person (e.g., a doctor in a hospital) is permitted.
Conventional techniques are disclosed in Japanese
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Unexamined Patent Publication Nos. Hei 7-245782, Hei 6-
326659 and Sho 64-29031 and Japanese Unexamined Utility
Model Publication No. Hei 4-103055.
In Japanese Unexamined Patent Publication No. Hei 7-
245782 is described a mobile radio device that forcibly
halts communication at a location where the use of a mobile
radio device, such as a portable telephone, should be
inhibited, and that changes the operation mode to one for a
pager so that calls can be received without disturbing
nearby people because of a communication over the telephone.
This mobile radio device will now be explained while
referring to Fig. 1.
The mobile radio device 71 comprises a pager module 72,
a power controller 73 and a portable telephone module 74.
The power controller 73 includes a mode selective switch
73a, a CPU 73b and a power supply circuit 73c.
In a mobile radio device 71 in Fig. 1, power generated
by a power supply circuit 73c is supplied to a pager or to
a portable telephone 74 by a switch in a power controller
73. The modes for which the pager 72 and the portable
telephone 74 are activated are called a pager mode and a
portable telephone mode, respectively. The power controller
73 is so set that it selects the portable telephone mode,
and supplies power generated by the power supply circuit 73c
to the portable telephone 74. As a result, the mobile radio
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device 71 is set in the portable telephone mode and func-
tions as a portable telephone. When, while waiting for a
call, a user passes through a mode switch signal transmitter
75 that is installed at a ticket gate in a station, etc., a
mode select receiver 73a in the power controller 73 receives
a mode select signal, and a CPU 73b changes the mode of the
mobile radio receiver 71 to the pager mode, so that there-
after the mobile radio receiver 71 functions as a pager.
That is, the power generated by the power supply circuit 73c
is supplied to the pager 72.
When a call from another user is received while in the
pager mode, the caller is notified that the radio device is
in the pager mode. Either when a mode select signal is
received from the mode select signal transmitter 75 when the
user exits through a ticket gate of the station, or when a
select switch provided for the key pad of the mobile radio
device 71 is manipulated, the mode of the mobile radio
device 71 can be changed from the pager mode to the portable
telephone mode. Therefore, so long as the radio receiver 71
receives a mode select signal from the mode select trans-
mitter 75 when passing through a gate, the mobile radio
receiver 71 can be switched from the portable telephone mode
to the pager mode, or vice versa, without any action being
required of a user.
In Japanese Unexamined Patent Publication No. Hei 6-
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326659 is described a portable telephone that when lost
prevents its unauthorized use and assists in its discovery.
The portable telephone comprises: locking means, for
inhibiting various operations, such as calling, the recep-
tion of calls and the retrieval of memory; input means, for
entering data to change the locked state; storage means, for
storing the locked state; and control means, for controlling
the various individual means. The thus arranged portable
telephone can not only receive a telephone number for a
regular call, but can also receive a sub-address that
accompanies the telephone number, and can control various
operations by using the sub-address. In addition, the
portable telephone includes display and tone generation
means for employing the sub-address to provide various types
of displays and to generate sounds. Actually, the lock
information and a display are changed upon the receipt of
the sub-address during a wait period for the portable
telephone.
When the portable telephone is stolen or lost and is in
the possession of a third party, the locking state is
altered by using the sub-address, and the inhibition of the
calling process and the reception of calls, and the inhibi-
tion of the changing and the retrieval of memory are
performed to avoid unauthorized use of the telephone.
Further, a message to contact the owner is shown on the
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display and an audible signal is produced by tone generation
means to assist in the discovery of the portable telephone.
In Japanese Unexamined Patent Publication No. Sho 64-
29031 is provided a radio telephone system, wherein a master
device (base station), which is connected to a cable line,
is connected to a plurality of mobile radio communication
terminals that control calls originated at an arbitrary
mobile radio communication terminal.
In the radio telephone system, the master device
defines passwords for individual terminals connected thereto
by radio. To use the terminal, a user must input a specific
password, and if the password does not match the password
defined by the parent device, calling is inhibited.
In Japanese Unexamined Utility Model Publication No.
Hei 4-103055 is provided a portable telephone that compris-
es: a memory, for registering in advance a password that is
used to set or release a locking mode for inhibiting all, or
a part, of call and call reception operations; a comparator,
for comparing a number input for this use with the password
registered in the memory; a mode selector for setting and
releasing the locking mode; and a controller for inhibiting
all, or a part, of the call and the call reception opera-
tions when the locking mode is set.
This portable telephone can not transmit a call or
receive a call so long as the password that is registered in
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advance is not input, and thus prevents the unauthorized use
by a third party.
According to the mobile radio communication technique,
a base station performs a call transmission and reception
process, a control process, such as the registration of a
position, and a communication process for actual user data
such as for example speech data relative to all the mobile
radio communication terminals that are within a range of a
signal emitted by the base station.
However, even when a location where the use of a mobile
communication terminal should be limited falls within the
range (the reception range) of the signal emitted by the
base station, it is difficult to inhibit the transmission of
a signal.
Example locations whereat the use of the mobile
communication terminal should be limited are on trains,
where problems concerning user manners has arisen; in
medical facilities, where there are many delicate medical
devices, such as pacemakers, that may be erroneously
operated by high frequency signals transmitted by a mobile
communication terminal; and in prisons and in police station
cells.
The above described shortcoming arises because the
service range of a base station is broader than the range
(the limited use range) wherein the use of a mobile communi-
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cation terminal is to be limited so that the limited use
range is situated within the service range.
Among the conventional techniques for limiting or
inhibiting the use of a portable communication terminal, the
techniques disclosed in Japanese Unexamined Patent Publica-
tion Nos. Hei 6-326659 and Sho 64-29031 and in Japanese
Unexamined Utility Model Publication No. Hei 4-103055 limit
or inhibit the use of the mobile communication terminal.
However, when a matching password is entered, i.e., when the
inhibition imposed on the operation, or the locking of the
operation is released, there is no means available by which
to disable the operation.
In Japanese Unexamined Patent Publication No. Hei 7-
245782, when the mobile communication terminal is powered on
in the limited use range, it operates in the normal portable
telephone mode.
SUMMARY OF THE INVENTION
To overcome the above shortcoming, it is an object of
the present invention to locally limit or inhibit the use,
i.e., the transmission and reception of calls, of a mobile
communication terminal, such as a pager (a selective calling
system), a portable radio device, a telephone or a cordless
telephone, in a mobile communication system that permits
radio communication between the mobile communication
terminal and a base station that supports a communication
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service for the mobile communication terminal.
According to the present invention, across a radio
channel that differs from a radio channel used by a base
station, a control signal is transmitted to a mobile
communication terminal to inhibit or limit its operation.
Upon receipt of the control signal, the mobile communication
terminal inhibits or limits its own use. The radio channel
is, for example, a frequency band in an FDMA (Frequency
Division Multiple Access), a time slot in a TDMA (Time
Division Multiple Access), or a spread code in a CDMA (Code
Division Multiple Access).
More specifically, a mobile communication system 1 in
Fig. 2 comprises: transmission means (a control signal
transmitter 2 in Fig. 2), for transmitting a control signal
to a mobile communication terminal to inhibit or limit the
use of the terminal; and a mobile communication terminal
device (a mobile communication terminal 3 in Fig.2), which
includes reception means (a receiver 3a in Fig. 2) for
receiving a control signal, control means (a controller 3b
in Fig. 2) for employing a received control signal to
control the use of the mobile communication terminal, and
display means (a display device 3c in Fig. 2) for notifying
a user of the state of the control means by using a visual
display or sound.
In the mobile communication system of the present
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invention, across a radio channel that differs from the
radio channel employed for a frequency used by a base
station that provides a communication service, the trans-
mitter transmits a control signal to the mobile communica-
tion terminal to inhibit or limit its operation. The mobile
communication terminal, which has been powered on, first
receives this control signal. When the operation of the
mobile communication terminal has not yet been inhibited or
limited even though the control signal has been detected, as
in the conventional case, the receiver of the mobile
communication terminal is adjusted to a radio channel of the
base station that provides a communication service for the
performance of transmission and reception.
As a result, the operation of the mobile communication
terminal can be locally inhibited or limited even within the
transmission range (the service range) of the signal from
the base station that provides the communication service for
the mobile communication terminal.
When the operation of the mobile communication terminal
is halted upon the receipt of the control si~nal for the
inhibition or the limiting of the operation, a user can be
notified of the current state audibly or by a visual
display.
An identification number is stored in advance in the
transmitter and in the mobile communication terminal. When
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a control signal that includes the identification number of
a specific mobile communication terminal is broadcast by the
transmitter, the operation of the mobile communication
terminal can be inhibited or limited, or can be restored.
In addition, since the transmitter can vary the power
of a transmission signal, the range of a control signal for
inhibiting or limiting the operation of a terminal can be
changed.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is block diagram illustrating a conventional
mobile radio device;
Fig. 2 is a block diagram illustrating a mobile
communication system according to a first embodiment of the
present invention;
Fig. 3 is a block diagram illustrating a mobile
communication system according to a second embodiment of the
present invention; and
Fig. 4 is a block diagram illustrating one arrangement
of a control signal transmitter in the mobile communication
system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention will
now be described while referring to the accompanying
drawings.
A specific mobile communication system (hereinafter
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referred to as a "communication system") according to a
first embodiment of the present invention will be described
while referring to Fig. 2.
As is shown in Fig. 2, a communication system 1
comprises: a control signal generator 2, for generating and
transmitting a control signal to a mobile communication
terminal 3 to inhibit or limit its operation; and the mobile
communication terminal 3 that includes a receiver 3a for
receiving a control signal, a controller 3b for employing a
received control signal to control the operation of the
mobile communication terminal 3, and a display device 3c for
notifying a user of the state of the controller 3b. The
communication service is provided for the communication
system 1 by a base station 7.
The operations performed in this embodiment will now be
explained in detail while referring to Fig. 2.
In Fig. 2, area A, which is enclosed by the broken
line, represents the range of a signal emitted by the base
station 7 that provides the communication service for the
mobile communication terminal, i.e., the service area of the
base station 7; and area B, which is enclosed by a chained
line, represents the range (the reception enabled range) of
a signal generated and transmitted by the control signal
generator 2.
An explanation will now be given for the operation
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performed by the control signal generator 2 to inhibit the
operation of the mobile communication terminal 3.
The control signal generator 2 transmits a control
signal, the contents of which specify that the operation of
the mobile communication terminal 3 is to be inhibited. At
this time, radio channel Fb, which differs from radio
channel Fa that is used by the base station 7, is employed
for the transmission of the control signal.
When the mobile communication terminal 3 is powered on,
first, the receiver 3a receives a control signal across the
radio channel Fb. In this case, assume that the mobile
communication terminal 3 is powered on at point c within the
area B.
Upon the receipt of the control signal from the control
signal generator 2, the receiver 3a outputs the received
data to the controller 3b. Since the control signal
generator 2 has transmitted a control signal that indicates
the operation of the mobile communication terminal 3 is to
be inhibited, the result obtained by the reception and
detection is that "Operation is inhibited." In consonance
with this result, the controller 3b halts the operation of
the mobile communication terminal 3, and the display device
3c displays information to the effect that the operation at
a current location is inhibited to inform a user of the
status of the mobile communication terminal 3.
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Following this, assume that the mobile communication
terminal 3 is powered on at point d outside area B. In the
same manner as in the previous case, the mobile communica-
tion terminal 3 is powered on and the receiver 3a receives
a control signal across the radio channel Fb.
However, since point d is outside the area B of the
control signal generator 2, the control signal from the
control signal generator 2 is not received. Thus, the
control signal is not detected, and the result "No control
signal detected" is output to the controller 3b.
The controller 3b assumes that the mobile communication
terminal 3 can be operated in the current area, and sets up
the terminal 3 to receive a signal from the base station 7.
Actually, however, the receiver 3b receives a signal from
the base station 7 across radio channel Fa, and thereafter,
a normal communication (for example speaking) process is
performed.
During the normal communication with the base station
7, the controller 3b exercises control of the mobile
communication terminal 3 at constant predetermined intervals
to receive any control signals that may be transmitted
across radio channel Fb by the control signal generator 2.
Consider a case wherein the mobile communication
terminal 3 is moved from point d to point c while the
communication for speaking as example with the base station
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.
7 is in progress. When the mobile communication terminal 3
is moved from point d to point c and is in area B, the
mobile communication terminal 3 receives a control signal
across radio channel Fb from the control signal generator 2.
Since the control signal generator 2 has generated and
transmitted a control signal to inhibit the operation of the
mobile communication terminal 3, the result obtained by the
reception and detection is that "Operation is inhibited."
In consonance with this result, the controller 3 halts the
operation of the mobile communication terminal 3, and the
display device 3c then displays a notice for the user to the
effect that "Operation is halted because use is inhibited
this location."
A mobile communication system (hereinafter referred to
as a "communication system") according to a second embodi-
ment of the present invention will now be described while
referring to Fig. 3.
A communication system 1 shown in Fig. 3 comprises: a
control signal generator 2, which includes a memory device
8a for storing an identification number IDa that is deter-
mined in advance, and which transmits a control signal that
includes the identification number IDa to a mobile communi-
cation terminal 3 to inhibit or limit its operation; and the
mobile communication terminal 3, which includes a receiver
3a for receiving a control signal, a memory device 8b for
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storing an identification number IDb that is determined in
advance, a controller 3b that, to control the use of the
mobile communication terminal 3, compares the identification
number IDa that is included in a received control signal
with the identification number IDb stored in the memory
device 8b, ànd a display device 3c for notifying a user of
the state of the controller 3b. Furthermore, an explanation
will be given for a case wherein a radio channel used for a
control signal is a frequency band.
The operation in this embodiment will now be described
in detail while referring to Fig. 3.
Area B, which is enclosed by a chained line, in Fig. 3
represents the range (the reception range) of a signal
emitted by the control signal generator 2. Area A, which is
enclosed by the broken line, represents the range of a
signal transmitted by the base station 7 that provides a
communicatio~ service for the mobile communication terminal
3, i.e., the service range of the base station. Area B is
considerably smaller than area A and is completely contained
in area A. Point c is in area B (and also in area A), and
point d is in area A but is outside area B.
Identification numbers IDa and IDb are respectively
stored in the memory device 8a in the control signal
generator 2 and in the memory device 8b in the mobile
communication terminal 3.
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The control signal generator 2 transmits a control
signal indicating that operation of mobile communication
terminals other than a specific mobile communication
terminal (in this case, a mobile communication terminal for
5which the identification number IDa is stored in the memory
device 8a) is inhibited. That is, a control signal is
transmitted that indicates the operation of a mobile
communication terminal having an identification number other
than IDa is inhibited. The frequency band used for trans-
10mission is Fd, which differs from the frequency band Fc used
by the base station 7.
When the mobile communication terminal 3 is powered on,
first the receiver 3a receives a control signal across the
frequency band Fd. Consider a case where the mobile
15communication terminal 3 is powered on at point c in area B.
The receiver 3a receives a control signal from the
control signal generator 2, and outputs the reception result
to the controller 3b. It should be noted that the control
signal generator 2 transmits a control signal for the
20inhibition of the operation of mobile communication termi-
nals that have identification numbers other than IDa.
The controller 3b compares the identification number
IDa included in the control signal with the identification
number IDb stored in the memory device 8b.
25Assume that the identification number IDa included in
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the control signal differs from the identification number
IDb stored in the memory device 8b (IDa ~ IDb).
The controller 3b determines that "Operation of the
mobile communication terminal 3 is inhibited." In accor-
dance with the result, the controller 3b halts the operation
of the mobile communication terminal 3. The display device
3c displays a message to the effect that "Operation of the
mobile communication terminal 3 is inhibited at this
location" to inform the user of this state.
Following this, when the identification number IDa
included in the control signal matches the identification
number IDb stored in the memory device 8b (IDa = IDb), the
controller 3c determines that "Operation is permitted." In
accordance with this result, the controller 3c assumes the
mobile communication terminal 3 is in an area where it can
be used, and enables the reception by the mobile communica-
tion terminal 3 of signals from the base station 7.
Actually, the receiver 3a receives signals from the base
station 7 across frequency band Fc. A normal communication
(speaking) process is thereafter performed.
During the normal communication (speaking) with the
base station 7, the controller 3b exercises control at
constant predetermined intervals to receive any signals
transmitted across a frequency band Fd. A control signal
indicating "Operation is enabled" is consistently received
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in area B.
Assume a case where the mobile communication terminal
3 is shifted out of the area B while the communication
(speaking) with the base station 7 is in progress, and
enters a range (area C, which is enclosed by the chain
double-dashed line) where the operation of the mobile
communication terminal 3 is inhibited.
It should be noted that in area C a control signal
generator 2' transmits a control signal granting operating
permission only to a mobile communication terminal for which
an identification number IDc is stored in the memory device
8C ( IDc ~ IDb).
The mobile communication terminal 3 then receives a
control signal across frequency band Fc from the control
signal generator 2'.
Since the control signal generator 2' has transmitted
a control signal granting operating permission only for a
mobile communication terminal that has the identification
number IDc, the receiver 3a of the mobile communication
terminal 3 obtains the reception and detection result
"Operation is inhibited." In accordance with this result,
the controller 3b halts the operation of the mobile communi-
cation terminal 3, and the display device 3c displays the
message "Operation is halted because the use at this
location is inhibited" to inform the user of the status of
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the mobile communication terminal 3.
In the second embodiment, a frequency band different
from that used by the base station has been employed for
transmission of a control signal. But instead of the
frequency band, a time slot or a spread code can be used.
Specifically, it is apparent that so long as there is
a usable radio channel in addition to a radio channel that
is used by the base station for normal communication, that
radio channel can be used for transmission of a control
signal concerning the operation of a mobile communication
terminal.
Another arrangement for the control signal generator 2
is shown in Fig. 4.
The control signal generator 2 in Fig. 4 includes a
variable transmission power output device 9 for varying a
power value for transmission of a control signal, and a dial
(level) 10 is provided outside the control signal generator
2 to operate the variable transmission power output device
9. A user manipulates the dial 10 to vary the power of a
control signal that is output by the control signal gener-
ator 2.
With this arrangement, the range spanned by a control
signal, i.e., the size of area B in Figs. 2 and 3, can be
changed as desired.
Therefore, the range wherein the operation of the
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mobile communication terminal 3 should be inhibited or
limited can be changed.
According to the first effect obtained by the mobile
communication system of the present invention, the control
signal generator 2 transmits a control signal, which
specifies that the operation of the mobile communication
terminal 3 will be inhibited or limited, across the radio
channel Fb, which differs from the radio channel Fa used by
the base station 7. When the mobile communication terminal
3 is powered on, first the receiver 3a receives the control
signal and transmits the received data to the controller 3
for evaluation, so that the operation of the mobile communi-
cation terminal 3 can be inhibited or limited.
As a result, it is possible to inhibit or limit the
operation of the mobile communication terminal in a specific
area (area B or area C in Figs. 2 and 3) within the range of
the control signal emitted by the control signal generator
2.
Furthermore, a control signal is received at predeter-
mined time intervals even after normal communication for
speaking as an example has been permitted. Therefore, when
the mobile communication terminal is moved to a location
where its operation is inhibited or limited, the operation
of the mobile communicatlon terminal can be inhibited or
limited.
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As is shown in Fig. 3, the memory device 8a in which
the identification number IDa is stored, and the memory
device 8b in which the identification number IDb is stored
are respectively provided for the control signal generator
2 and the mobile communication terminal 3. When a control
signal including the identification number IDa is transmit-
ted by the control signal generator 2, the operation of a
specific mobile communication terminal can be inhibited or
limited.
In addition, as is shown in Fig.4, the variable
transmission power output device 9 is included in the
control signal generator 2, and the dial (level) 10 is
provided outside the control signal gyenerator 2 for operat-
ing the variable transmission power output device 9. With
this arrangement, the range within which the inhibiting or
the limiting of the operation of the mobile communication
terminal can be varied.
