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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to a radio telephone system used for a
cordless telephone, an automobile telephone or the like.
DESCRIPTION OF THE PRIOR ART
A radio telephone system is well known, comprising a plurality of radio
telephone sets (RTEL) such as cordless telephone sets or automobile
telephone sets making up mobile stations, a plurality of radio connectors
(CE) arranged in a plurality of radio zones respectively for radio
communication with the radio telephone sets, a radio channel control unit
(RCU) for communicating with the radio connectors (CE) and a private
branch exchange (PBX), an office exchange or the like exchange connector
connected with the radio channel control unit (RCU) thereby to establish
communications between different radio telephone sets (RTEL) or through a
trunk line of the radio telephone sets (RTEL).
The radio channel control unit (RCU) and the radio connector (CE) mentioned
above are similar to the system control station and a base station of each
radio zone in the automobile telephone system, respectively.
In this radio telephone system with the radio telephone sets (RTEL) making
up mobile stations, it is necessary that the radio zone where a radio
telephone set (RTEL) is located is registered or entered in the radio
channel control unit (RCU) before forming a communication path of the
radio telephone set (RTEL).
In conventional radio telephone systems of this kind, the position data
indicating each radio zone is constantly announced by the radio connector
(CE) providing a stationary station in order to register the radio zone
covering a radio telephone set (RTEL), so that each radio telephone set
(RTEL) constantly monitors the present radio zone by this position data.
When moving between radio zones, the radio telephone set thus sends out a
position entry demand signal and an ID number automatically thereby to
register the position data of each radio telephone set (RTEL) with the
radio channel control unit (RCU).
The conventional radio telephone system described above, however, is
required to keep on the power supply of the radio telephone sets (RTEL)
making up mobile stations in order to keep monitoring the position data
from the radio connectors, thereby posing the problem of power consumption
by the radio telephone sets (RTEL).
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a radio
telephone system capable of registering the position of a radio telephone
set automatically while reducing power consumption thereof.
In order to solve the above-mentioned problem, there is provided according
to the present invention a radio telephone system in which each radio
telephone set has a receiving circuit the power of which is turned on or
off in predetermined cycles, each radio connector transmits an ID number
of the radio zone for a longer period than the period of turning on or off
of the power supply of the receiving circuit of the radio telephone set in
predetermined cycles, the radio telephone set comparing the ID number of
the radio zone received when the power supply of the receiving circuit is
on with that stored in a memory, and when the ID numbers fail to coincide
with each other a predetermined number of times (say, twice) successively,
the ID number of the radio telephone set and the ID number of the radio
zone received are transmitted as a position entry signal to the radio
channel control unit through the radio connector at a timing formed on the
basis of the ID number of the radio telephone set, the radio channel
control unit being adapted to register the ID number of the radio
telephone set and that of the radio zone.
According to the present invention, the position of each radio telephone
set is capable of being registered without keeping on the power supply of
the receiving circuit of the radio telephone set, thereby reducing the
power consumption of the radio telephone set.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a general configuration of a radio telephone
system embodying the present invention.
FIG. 2 is a block diagram showing each device of the radio telephone system
of FIG. 1 in detail.
FIGS. 3A, 3B, 3C, 3D and 3E are diagrams for explaining the files of the
radio channel control unit in FIGS. 1 and 2.
FIGS. 4A and 4B are diagrams for explaining the files of the radio
connector of FIGS. 1 and 2.
FIGS. 5A, 5B, 5C, 5D and 5E are diagrams for explaining the files of the
radio telephone set shown in FIGS. 1 and 2.
FIG. 6 is a timing chart for explaining the operation of the radio
telephone system shown in FIGS. 1 and 2.
FIG. 7 is a diagram showing a control sequence for explaining the operation
of the radio connector shown in FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention will be explained below with
reference to the accompanying drawings.
In FIG. 1, reference numeral 11 designates a stationary station connected
to an existing telephone exchange 10, which makes up a radio channel
control unit (RCU) for controlling the radio telephone system as a whole.
Numerals 12.sub.1 to 12.sub.n designate stationary stations providing
small-power radio connectors (CE) with a communication radius of about 30
to 100 m, each of the radio connectors 12.sub.1 to 12.sub.n including a
plurality of units. Each of the radio connectors 12.sub.1 to 12.sub.n
makes up each corresponding one of radio zones Z.sub.1 to Z.sub.n to
establish radio communication with a radio telephone set (RTEL) located in
a corresponding radio zone.
Each of the radio zones Z.sub.1 to Z.sub.n makes up a radio service area
under the control of the radio channel control unit 11. An operator
carrying a radio telephone set 13 (in the case of cordless telephone),
when located within this service area, is capable of establishing
communication with other radio telephone sets 13 or through the trunk line
by way of the radio channel control unit 11 and the radio connectors
12.sub.1 to 12.sub.n.
The radio channel control unit 11 is connected to the existing telephone
exchange 10 through as many telephone lines as the radio telephone sets
13. The radio connectors 12.sub.1, 12.sub.2 to 12.sub.n are arranged in
the radio zones Z.sub.1, Z.sub.2 to Z.sub.n respectively at the rate of
one for each several radio telephone sets 13 in accordance with the
busy-hour traffic and loss probability.
Now, a detailed configuration of the radio channel control unit 11, the
radio connectors 12 and the radio telephone sets 13 will be explained with
reference to FIG. 2.
In the radio channel control unit 11, numeral 110 designates a control
section for controlling the radio channel control unit 11 as a whole. The
control section 110 includes a microcomputer (CPU), a ROM (read-only
memory) for storing an execution program for the CPU, and a RAM(random
access memory) having a working area for the CPU, etc.
Numerals 111.sub.1 to 111.sub.N designate trunk interfaces connected with
telephone lines respectively, numeral 112 a tone trunk for generating
various tone signals, numeral 113.sub.1 to 113.sub.m radio channel
interfaces connected to the radio connectors 12.sub.1 to 12.sub.n
respectively, and numeral 114 a matrix switch for connecting the trunk
interfaces 111.sub.1 to 111.sub.N, the tone trunk 112 and the radio
channel interfaces 113.sub.1 to 113.sub.m.
Numeral 115a designates, as shown in FIG. 3A, a system file for storing
various data including the ID number of the radio channel control unit,
that is, the ID number (SYS-ID) of the present system, the number n of
radio zones, that is, the number of control stations for the radio
connectors 12, the number of the radio connectors 12, station data for the
radio connectors such as the monitor timer value, and further including,
though not shown, such data as the program for the control section 120 of
the radio connector 12 and various data to be stored in the radio channel
connection file 125a and the station data file 125b.
Numeral 115b designates, as shown in FIG. 3B, a subscriber file for storing
call numbers (subscriber numbers) of the radio telephone sets 13, ID
number (RTEL-ID), the position data such as the radio zone number of the
current position and data on subscriber class. The position data is
rewritten upon movement of the radio telephone 13 between radio zones as
described below.
Numeral 115c designates, as shown in FIG. 3C, a station data file for
storing the numbers of the trunk lines and radio channels, and other
various data including the channel status indicating the present packaging
condition of a given channel.
Numeral 115d designates, as shown in FIG. 3D, a line connection file for
storing the call number (subscriber number) for the subscriber in speech,
the line number of the trunk line, the line number with the radio
connectors, the status of incoming/outgoing calls and line connection
time. Numeral 115f designates, as shown in FIG. 3E, a radio area file for
storing various data including the numbers of the radio zones, the number
of the radio connectors installed in the radio zones, and the ID numbers
of the radio connectors.
Numeral 116 designates a control console by which the operator enters
various data in the files 115a to 115f or the monitor result on the radio
connectors 12 making up control stations are displayed.
In each radio connector 12, numeral 120 designates a control section for
controlling each radio connector 12 in whole. The control section 120
generally includes a microcomputer (CPU), a ROM (read-only memory) for
storing an execution program for the CPU, and a RAM (random access memory)
having a work area of the CPU, etc.
Numeral 121 designates a radio transceiver of multi-channel access (MCA)
type for performing radio communication with the radio telephone 13,
numeral 122 a line interface connected to the radio channel control unit
11 through a two-wire (2W) transmission path, numeral 123 a control signal
transceiver for transmitting and receiving the control signal with the
radio channel control unit 11, and numeral 124 a voice control section for
turning on/off or amplifying the voice signal on the speech line.
Numeral 125a designates, as shown in FIG. 4A, a radio channel connection
file for storing various data including the present operating condition of
a particular radio connector 12, the ID number (RTEL-ID) of the radio
telephone in connection, the control sequence for processing
incoming/outgoing calls, various control signals for the radio telephone
13 (radio side) and various control signals for the radio channel control
unit (wire side).
Numeral 125b designates, as shown in FIG. 4B, an office data file for
storing various data including the ID numbers (SYS-ID) of the radio
channel control unit 11, the number of the radio zone in which a
particular radio connector is installed, the ID number of the particular
radio connector, the dial pause time for line wire transmission or the
like, the speed of the dial pulse (10 pps or 20 pps), the make ratio of
the dial pulse (33%, 50% or 66%).
In each radio telephone set 13, numeral 130 designates a control section
for controlling each radio telephone set 13 in whole. The control section
130 generally includes a micro-computer (CPU), a ROM (read-only memory)
for storing an execution program for the CPU, and a RAM (random access
memory) with a work area for the CPU or the like.
Numeral 131 designates a radio transceiver of multi-channel access (MCA)
type for effecting radio communication with the radio connector 12,
numeral 132 a transceiver for amplifying or turning on/off the voice
signal of the receiver or microphone of the handset 132a and generating
various tone signals (voice signals) corresponding to the call signals or
the like sent out from the radio channel control unit 11 through the radio
connector 12, numeral 133 a dial key for entering a dial number or the
like, numeral 134 a hook switch turned on/off by the off-hook/on-hook
state of the handset 132a, and numeral 136 a PB/DP change-over switch for
selecting the type (PB or DP) of the dial signal for the existing exchange
10.
Numeral 138a designates, as shown in FIG. 5A, a radio channel connection
file for storing various data including the connections of a particular
telephone set, the number of the radio connector 12 in connection, the
system number (SYS-ID) of the radio channel control unit 11 in connection,
the connection sequence with the radio connector 12 and the control signal
for the radio connector 12.
Numeral 138b designates, as shown in FIG. 5B, a radio telephone set ID file
for storing the ID number (RTEL-ID) of a particular telephone set 13,
numeral 138c a radio zone number file as shown in FIG. 5C for storing the
number (position data) of the radio zone in which a particular radio
telephone set 13 is located, numeral 138d an abbreviated dial file as
shown in FIG. 5D for storing an abbreviated dial number with a
corresponding dial code, and numeral 138e a redial file as shown in FIG.
5E for storing a dial code corresponding to the dial number entered
through the dial key the previous time.
The members 130 to 138e described above are encased in a portable housing
for the cordless telephone set, and a housing that can be installed on the
center console or the like of an automobile for the automobile telephone
set.
Now, the operation of the embodiment having the aforementioned
configuration will be explained.
(1) Position entry from the radio telephone set 13
With reference to FIGS. 6 to 7, the operation of the radio telephone set 13
registering the radio zone in which a particular radio telephone set 13 is
located will be explained.
First, as shown in FIG. 6, the control section 130 of the radio telephone
set 13, except while busy, turns of/off the power supply in a
battery-saving ratio of, say, 1 to 3, and while this power supply is off,
is supplied with a minimum power (for counting the battery saving period,
for example).
As shown in FIGS. 6 and 7, on the other hand, the radio channel control
unit 11 inverts the polarity of the transmission line loop to invert the
applied voltage for each radio connector 12 (control station) of each
radio zone in a predetermined cycle (say, 5 minutes) (sequence
(hereinafter referred to SQ) 1), sends out a sync signal (SQ2) and
restores the polarity of the loop (SQ4).
The radio connector 12 making up the control station of each radio zone
generates a position data announcing signal with the system ID number
(SYS-ID) and the radio zone number in the office data file 125b following
a preamble signal and a sync signal in response to the control sequence in
the radio channel connection file 125a, the control signal and the sync
signal, and sends out as a poling signal through the radio transceiver 121
(SQ3).
This announcement, as shown in FIG. 6 is repeatedly effected during a time
period (+time.alpha.) longer than the battery saving cycle of the radio
telephone set 13. Specifically, the operation of SQ1 to SQ4 are repeated
in five time slots in the case where the battery-saving cycles of the
radio telephone 13 occurs in the ratio of 1 to 3 as shown in FIG. 6.
As a result, even when there is an error of the counting time of the
battery saving cycle, each radio telephone set 13 is capable of receiving
a position data announcing signal from the radio connector 12 while the
power supply of its own is on. FIG. 6 shows the case where the position
data announcing signal has begun to be received at time slot 1.
The control section 130 of each radio telephone set 13, when receiving the
position data announcing signal including the signal of time .alpha.
through the radio transceiver 131, resets a timer for the battery saving
cycle so as to be able to provide for the receiving of the next position
data announcing signal, and furthermore compares the radio zone number of
the received position data announcing signal with the data in the radio
zone number file 138c.
As one example of reset timing, it is possible to reset at a time when the
radio zone number of the received position data announcing signal and the
radio zone number stored in the radio zone number file 138c coincide with
each other in the comparison of the two radio zone numbers.
In the case where these data coincide with each other, the power of the
receiving circuit is turned on/ off in the battery saving cycles. If these
data fail to coincide with each other a predetermined number of times
successively in the successive plural comparisons at times of receiving
the position data announcing signal, on the other hand, the control
section 130 generates a position entry demand signal including a preamble
signal and a sync signal with the ID number of the radio telephone set and
the received radio zone number in response to the control signal and the
control sequence in the radio channel connection file 138a and transmits
it through the radio transceiver 131 (SQ5).
This position entry demand signal is transmitted at random after receiving
the position data announcing signal from the radio connector 12. The
timing of transmitting the position entry demand signal is determined by
random numbers, for example, or the ID number of an associated radio
telephone set is divided by the number of time slots, and the remainder is
used to determine the time slot in which transmission is effected. FIG. 6
shows the case of transmission in the third time slot.
The radio connector 12, upon receiving the position entry demand signal,
transmits a position entry response signal to the radio telephone set 13
(SQ6), which rewrites the area of the radio zone number file 138c into the
ID number of the radio zone received.
The radio connector 12 also closes the loop of the transmission path with
the radio channel control unit 11 (SQ7), and generates and transmits a
position entry demand signal to the radio channel control unit 11 (SQ8).
The radio channel control unit 11 rewrites the position data of the
subscriber file 115b in response to the position entry demand signal and
transmits a position entry over signal to the radio connector 12 (SQ9).
The radio connector 12 transmits the position entry over signal to the
radio telephone set 13 (SQ10), while at the same time opening the loop
with the radio channel control unit 11 (SQ11).
The radio telephone set 13, upon receiving the position entry over signal,
turns on or off the power supply of the receiving circuit in the battery
saving cycles.
The position entry demand signal which is supplied as a special signal from
the radio connector 12 to the radio channel control unit 11 may be
replaced by some means of notification by opening or closing a line loop.
Also, instead of the position entry over signal from the radio channel
control unit 11 to the radio connector 12 may be replaced by some means of
polarity inversion of he line voltage or by sending a tone signal directly
to the radio telephone set 13 or sending the tone signal as a code signal.
As will be understood from the foregoing description, according to the
embodiment described above, the control section 130 of the radio telephone
set 13 turns on and off the power supply of the receiving circuit thereof
in battery saving cycles in the ratio of, say, 1 to 3 except when busy,
and while the power supply is off, supplies only minimum power (such as
for counting the battery saving time). Simply by these processes of
operation, the position data of the radio telephone set 13 can be entered
in the subscriber file 115b of the radio channel control unit 11.
(2) Incoming call to the radio telephone 13
Now, explanation will be made of an incoming call to the radio telephone
set 13 through the radio channel control unit 11.
Assume that a call arrives at the extension 13X1 via the existing exchange
10. The existing exchange 10 accesses the control section 110 of the radio
channel control unit 11 through the trunk interface 111 receiving the
call.
The control section 110 reads out the radio zone associated with the radio
telephone (13X1) from the subscriber file 115b, and sends out the ID
number of the radio telephone set (13X1) and a call control signal to the
control station of the radio connector 12 arranged in the particular radio
zone. In the process, the control section 110 controls a matrix switch 114
thereby to connect the radio channel interface corresponding to the
control station of the radio connector 12 for the particular radio zone
with the trunk interface 111 associated with the incoming call.
The control section 120 of the radio connector 12, upon receiving the call
signal and the like through the line interface 122 and the control signal
transceiver 123, generates the call control signal and the ID number for
the radio telephone set (13X1) for radio communication on the basis of the
control signal data of the radio channel connection file 125a, transmits
these signals repeatedly for a time period (+.alpha.) longer than the
battery saving cycle of the radio telephone set 13 like the pattern shown
as a calling signal in FIG. 6.
The control section 130 of the radio telephone set 13, as explained with
reference to FIG. 6, turns on/off the power supply of the receiving
circuit in predetermined battery-saving cycles, and when the power supply
is on, receives a call control signal and a signal representing the ID
number of the radio telephone set (13X1) thereby to keep the power on.
Then, the ID number received is compared with the ID number in the radio
telephone set ID file 138b, so that the control section 130 of the radio
telephone set (13X1) for which the ID numbers coincide with each other
turns on the transceiving section 132 thereof. The transceiving section
132 thus generates a voice signal for calling in response to a control
signal from the radio connector 12.
In this way, calling signals from the existing exchange 10 are transmitted
in sequentially different signal formats to the radio telephone set (13X1)
through the radio channel control unit 11 and the control section of the
radio connector 12.
With the off-hook of the radio telephone (13X1), the particular data is
sent out to the control station of the radio connector 12 and the radio
channel control unit 11, so that the control section 120 of the radio
connector 11 establishes a communication path with the calling telephone
set and the radio telephone set (13X1) by turning on the voice control
section 124.
Upon termination of speech, the control section 130 of the radio telephone
set 13 turns on the power supply and restarts the battery saving cycles.
(3) Transmission from radio telephone set 13
Now, the operation of transmission from the radio telephone set 13 to the
trunk line or other radio telephone sets 13 will be explained.
With the off-hook of the radio telephone set 13 to turn on the hook switch
134, the power supply is turned on, and the associated control section 130
generates a calling signal in response to the connection sequence and the
control signal in the radio channel connection file 135 and together with
the ID number of the present radio zone in the radio zone number file
138c, sends out the calling signal to the radio connector 12.
The control section 120 of the control station of the radio connector in
each radio zone compares the ID number thus received with the ID number of
its own radio zone in the office data file, and if they coincide with each
other, transmits a call response signal and a signal designating a speech
channel to the radio telephone set 13, with the result that the particular
radio connector 12 acts as a busy station.
Upon transmission of a channel switching signal from the control section
130 of the radio telephone set 13, the radio connector 12 closes the loop
with the radio channel control unit 11. Also, when the control section 130
of the radio telephone set 13 produces an interference detection over
signal in the absence of interference with an adjacent radio zone, the
radio connector 12 transmits a calling signal to the radio channel control
unit 11. The radio channel control unit 11, in turn, closes the loop of
the subscriber line on the existing exchange side upon receiving the
calling signal, and notifies the call to the existing exchange 10.
In the next moment, the control section 110 of the radio channel control
unit 11 transmits a call response signal to the particular radio connector
12, and with the turning on of the voice control section 124, transmits a
voice circuit start signal to the radio telephone set 13. The control
section 130 of the radio telephone set 13 turns on the transceiving
section 132 in response to the voice circuit start signal.
As a result, the dial tone transmitted from the existing exchange 10 to the
radio telephone set 13 t | | |
