⑲ Japan Patent Office (JP)
`⑪ Patent application published
`⑫ Public Patent Gazette (a)
` 2-44929
` 1990 (1990) February 14
`
` Identification number
` 1 〇 6
` 7608-5K
`
` © Int.CL5
` H 04 B 7/26
`
` Number of unclaimed claims for examination 1 (19 pages)
`
`
`
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`
` The name of the invention Mobile position detection method
` ㉑ 63-195800
` ㉒ 63 (1988) August 5
`1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo
`
`Male
`
`Shu
`n
`
`Kat
`a
`
`Sha
`ng
`
`Light
`
`Takesh
`i
`
`1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo
`
`1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo
`
`1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo
`1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo
`
` Shares of Nippon
`Telegraph and
`Telephone Corporation
` Shares of Nippon
`Telegraph and
`Telephone Corporation
` Shares of Nippon
`Telegraph and
`Telephone Corporation
` Shares of Nippon
`Telegraph and
`Telephone Corporation
`
` Naotaka IDE, patent
`attorney, Nippon Telegraph
`d T l h
`C
`i
`
` It was written in fine detail
`
`1.
`
` Name of the invention
` Mobile position detection method
`
`2.
`
` Claims
` 1, in the method of detecting the position of a mobile body in the mobile
`communication method, which communicates with a base station and a mobile
`body by radio waves,
` The mobile device receives radio waves from multiple base
`stations, finds the range of possible existence of the mobile
`device corresponding
`to each receiving
`level using
`the
`equielectric field curve of the received electric field level from
`each base station obtained beforehand, and detects the position
`of the mobile device from the overlap of each range
` A method of detecting the position of moving objects, which
`is characterized by.
`
`3.
`
` Detailed description of the invention
` "Industrial use"
` This invention is used in the field of mobile communications.
` The present invention relates to a method for detecting the
`position of a mobile station in a mobile communication system such
`as a car-phone system, in particular, a method for detecting the
`position of a mobile station in an area by checking the received
`
`electric field level at a mobile station of a base station transmission
`wave with an electric field strength map.
` "Traditional Technology"
` In the mobile communication system, which consists of
`multiple radio zones, such as the automobile telephone system, it is
`necessary to know the current position of the mobile circumference
`that moves around a wide area, and to connect the line between the
`mobile station and the fixed network, etc. The mechanism is
`explained below using the car telephone system as an example 〇
` (Method Configuration)
` As shown in Figure 19, the radio section of the car telephone
`system consists of 10 mobile stations, 20 base stations, and 40 mobile
`communication control stations. Base station 20 is responsible for
`transmitting radio signals to and from mobile station 10. The mobile communication
`control station 40 controls multiple base stations and is responsible for the interface
`with the fixed network.
` (Zone Configuration)
` In the automobile telephone system, which provides large-
`capacity nationwide wide-area service, the service area is divided
`into multiple radio zones 30, as shown in Figure 20, for reasons
`such as limiting the transmission output of 10 mobile stations and
`effective use of frequency. a base station 20 is installed in each radio
`zone 30, and the same frequency is used between the base stations
`that do not generate interference.
`
`1
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` 2
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`Page 1 of 38
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`SAMSUNG EX-1012
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` Special clearing2 — 44929(#)2
`
` In order to efficiently perform incoming service wherever a
`mobile station is in the service area, the car phone system divides
`the service area into multiple areas, and the location of the mobile
`station is registered on the replacement machine as the location
`identification unit (also called the location registration area, or the
`global call area) of the mobile station. it adopts the method of
`calling only in the area where the called mobile station is located.
`The location registration area usually corresponds to the control
`zone described below.
` (Radio Channel Configuration)
` A mobile station uses multiple radio channels in common and
`selects a specific radio channel for each call. As shown in Figure
`20, the radio channel consists of the communication channel 141,
`which is used for communication, and the control channel 141,
`which is used for controlling the allocation of communication
`channel 141 according to the call request from the subscriber. The
`
`control channel consists of the incoming control channel 142,
`which is used for the incoming call connection to the mobile
`station IO and the simultaneous notification of control
`information, and the outgoing control channel 143, which is used
`for the outgoing call connection from the mobile station IO and
`the reporting and registration of the status of the mobile station 10.
` There are two ways to place the control channel:
`① Multiple radio zones are arranged as a single unit, or control
`zone. That is, there are multiple radio zones in each control zone,
`and a name radio zone has the same number of incoming and
`outgoing control channels and the same frequency.
`② For the incoming control channel, multiple radio zones are
`designated as one unit (control zone), and for the outgoing
`control channel, each radio zone is assigned. That is, the
`incoming control channel is the same as in the case of ①, but the
`outgoing control channel is the same
`
`in order to make or receive a call to a mobile station that is moving,
`and the position detection and registration for determining the area
`to call simultaneously is called position logging.
` The mobile station remembers the reception control channel
`number (corresponding to the frequency) used in the control zone
`throughout the country, and during listening, it selects and receives
`the incoming control channel with the highest reception level from
`among these channels, and uses the positional information signal
`(control zone identification number) contained in the control zone
`to which it is located
`
`
`
`
`
`
`
` The system depends on the control traffic of each radio zone
` How to place the chisel
` And so on.
` The transmission and reception methods of control signals in ①
`and ② are shown below.
` What is it
`①
` For
` For control signals from the base station to the mobile station,
`both the outgoing and incoming control channels are transmitted
`simultaneously from all base stations in the control zone. This
`method is called "multiple simultaneous transmission system".
`②
` For
` Transmission Control the control signals from a base station to
`a mobile station of ① Nel are basically the same as in the case of the
`above. However, control signal 150 from the base station to the
`mobile station of the incoming control channel consists of signals
`transmitted simultaneously from all base stations in the control zone
`(shaded areas in the figure) and signals transmitted separately from
`each radio zone in turn. these are transmitted from the base station
`on a regular basis. This system is called "multiple-station
`simultaneous/sequential transmission system". In Figure 21, 151 is
`a common
`information signal to transmit common control
`information to all radio zones in the control zone, 152 is an incoming
`information signal to transmit incoming control information to
`mobile stations, and 153 is a base station information signal to
`transmit specific information to each radio zone. Common
`information signal 151 and incoming control information signal 152
`are transmitted simultaneously by all base stations in the control
`zone, but the base station information signal 153 is transmitted by
`each base station in turn. The base station information signal 153
`includes the identification number of the base station.
` (Location registration)
` It is necessary to detect the current position of the mobile station
`
` 5
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`Page 2 of 38
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`

`
`
` Special clearances 2-44929(#)3
`
`To identify the. When the mobile station switches the incoming
`control channel by moving the position registration unit (that is, the
`control zone), if the identification number before the switch and the
`identification number after the switch are different, the position
`registration signal is transmitted to the wireless base station by the
`upstream line of the outgoing control channel.
` (Determination of Mobile Localization coil Radio Zone)
` In order to assign a call channel to a mobile station when a call
`is made to or from a mobile station, it is necessary to determine the
`regional radio zone of the mobile station.
` In the Automotive Telephone System, which adopts the
`"multiple-station simultaneous transmission method", the mobile
`localized radio zone is determined by comparing the reception level
`at the base station of the response signal of the mobile station or the
`call signal from the mobile station.
` On the other hand, in the car phone system that adopts the
`"multiple station simultaneous/sequential transmission method", the
`mobile station compares the level of the base station information
`signal included in the control signal from the base station of the
`incoming control channel to the mobile station, and the mobile
`
`station determines the mobile zone by determining that it is located
`in the zone of the base station that transmits the highest base station
`information signal.
` In this way, in order to connect the line between the mobile
`station and the fixed network, the base station always registers the
`location of the mobile station in the control zone unit, and when the
`mobile station comes and goes, it identifies the local radio zone of
`the mobile station in order to assign the call channel to the mobile
`station.
` [Problems to be solved by the invention]
` However, since the location of the mobile station is determined
`only by the radio zone, the accuracy of location identification is
`rough, with a radius of several kilometers to several tens of kilometers
`(the radio zone in the car phone system is about 3 km to 15 blood). In
`addition, there was a drawback that it was impossible for the mobile subscriber or the
`fixed subscriber to know the location of the mobile station, especially the location of
`the mobile station, because the radio zone of the mobile station was only known in the
`radio section of the car telephone system.
` Furthermore, in recent years, we have been supporting the
`advancement of information technology in society
`
`
`
`
` 7
`
` Although the movement of people and goods is becoming more
`active due to the development of road transportation networks, the
`need for smooth movement of people and cars is increasing due to
`the increasing number of road congestion and the range of
`movement is expanding. For this reason, a V M system (Automatic
`vehicle Monitoring System) is being developed to constantly monitor
`the position of moving objects and improve the efficiency of vehicle
`operation by broadcasting location information wirelessly from
`signposts, and a 5 GPS (Global Positioning System) is being developed to
`detect the position of moving objects using satellites. ■ 5 GPS (Global
`Positioning System) is also being developed. In these systems, the accuracy of
`position detection is relatively high at several tens of meters, but there is a drawback
`in that it is necessary to make capital investments such as the installation of signposts
`or the launch of satellites in addition to terminals on the mobile body side.
` The purpose of the present invention is to provide a mobile
`detection method that can detect the position of a mobile body
`within a mobile communication method area with a higher accuracy
`than that of a wireless radio unit by eliminating the aforementioned
`disadvantage, and can also detect the position of a mobile body in a
`mobile communication method or its communication counterparty.
`
` 8
`
` "The way to solve the problem"
` In the method of locating a mobile body in a mobile
`
`communication method that uses radio waves to communicate
`between a base station and a mobile body, the present invention
`receives radio waves from multiple base stations by the mobile
`body respectively, uses the equelectric field curve of the received
`electric field level from the customer base station obtained
`beforehand, and finds the possible range of the mobile body
`corresponding to the customer reception level, and determines the
`position of the mobile body from the overlap of the customer range.
` [Action]
` The principle of the present invention is explained below.
` The radio wave transmitted from the base station becomes
`weaker as it moves away from the base station. Therefore, if the
`strength of the radio wave received by the mobile station, i.e. the
`level of the received electric field, it can be estimated to what extent
`the mobile station exists from the base station. Because the
`topography around the base station is not uniform and there are
`various features such as trees and buildings, the equielectric field
`line of the receiving radio wave of a mobile station is generally not
`concentric circle around the base station, but if the equielectric field
`line is drawn by some method, the mobile station will exist
`somewhere on the equielectric field line corresponding to the
`receiving electric field level.
` Since the direction of the mobile station cannot be determined
`by just receiving radio waves from one base station, the position of
`the mobile station can be determined only somewhere on the
`isoelectric field around the base station. if the radio zones of BU22 and B3
`(23) overlap and the mobile station (10) can detect the received electric field level of
`each base station radio wave, the position of the mobile station (10) can be obtained
`from the intersection of the equielectric field lines of each base station radio wave.
`
` 9
`
` ! 〇
`
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`

`
`
` 2-44929(4)
`
` Normally, it is quite difficult to obtain the exact equielectric
`field wire in detail, so the position of the mobile station 10 that can
`be detected is not a point but a certain spread. That is, as shown in
`the field strength map in Figure 2, if the received field level equals at three
`base stations B, (21), B2 (22) and B3 (23) 10) are obtained as shown in the
`figure, if the received field level of B, (21) is 52 dB V/m at the mobile station B,
`(21), and the base station (22) is 45 dB/z3). the mobile station (10) exists
`somewhere in the part enclosed by the thick frame in the figure. As
`the number of base stations that can be received by a mobile station
`(1 〇) increases, it is possible to narrow the existence range of the
`mobile station (10) even more.
` Based on the above idea, the present invention:
`① A mobile object can identify and receive radio waves from
`
`multiple transmitting points.
`② For each transmission point, a map of the electric field strength
`of the received electric field level of the moving body of the radio
`wave from the transmission point is obtained beforehand.
`③ The received electric field level and the electric field strength of
`the mobile object are checked for multiple transmission points,
`and
`the position of
`the mobile object
`is detected by
`superimposing the range of possible existence of the mobile
`object obtained on the electric field strength map. The field
`strength map can be stored in the memory area of the information
`processing device, and the processing can be executed by
`program control.
`④
` Radio waves from multiple transmitting points are each
`mobile
`
` The following describes the working example of the present
`invention by referring to the drawing.
` Figure 3 shows the block configuration diagram showing the
`mobile communication system based on the first working example
`of the present invention.
` The first example is a base station with radio zone 31 6,21, a base
`station with radio zone 32, a base station B2 22 with radio zone 32, a
`base station B323 with radio zone 33, and several other radio zones
`indicated by the dashed line, a mobile communication control station
`40 that controls these, a location information center 40 and a location
`information center that is connected by this mobile communication
`control station 40 and the first communication line 51
`
`
`
`
` 11
`
` As a method of identification and reception, a service area is
`composed of multiple radio zones, and a wireless base station is
`installed in each radio zone, and control signals from the base
`station to the mobile station are transmitted from each base station
`individually with the base station number. In the mobile
`communication system,
`the mobile station detects
`the
`KAKUSHIN electric field level of the base station number and
`the control signal transmitted by the base station from the base
`station to the mobile station. Or, when the control signal from the
`base station to the mobile station is not transmitted from the
`winter base station individually with the base station number, the
`radio channel received by the mobile station is switched
`sequentially, the received electric field level of each radio channel
`is detected, and the received electric field level of each radio
`channel is detected by correspondence between the radio channel
`and the base station transmitting the radio channel signal.
`⑤ In the mobile communication system described above, ④ the
`electric field strength map for each base station is installed at the
`mobile station,
`the base station, or
`the communication
`counterparty of the mobile station, and the base station number
`detected by the mobile station and the received electric field of
`the transmit wave of the base station
` 1 2
`
` The bell can detect your position on the mobile station, or
` The base station number detected by the mobile station and the
`received electric field level of the base station transmit wave are
`transmitted to the base station or the communication partner of
`the mobile station through a communication line, and the location
`of the mobile station is detected by comparing the received
`electric field level and the electric field strength map of each base
`station at the destination.
` [Examples]
`
` 1 3
`
` 1 4
`
` 168
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`Page 4 of 38
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`

`
`
`
`
`
`
`
`
`It contains 60 and multiple location information users 70 and each has a position
`information receiver 71 connected by a second communication line 52.
` There is a mobile station 10 in radio zone 31 of base station 8,21,
`and wireless zone 32 of base station B 2 22 and wireless zone 33 of base station B323
`overlap in radio zone 31, and transmission waves of base station 6,21 Bs22 and B
`3 2 3 can be received in mobile station 10. Mobile station 10 is connected to
`Location Information Center 60 via base station B/1, mobile
`communication control station 40, and first communication line 50.
`The field strength map 90 is the same as the one shown in Figure 2.
`The first communication line 51 is usually a fixed telephone line, but
`it may be a packet communication line, ISD N line, mobile
`communication line, etc. by changing the interface conditions
`between the mobile communication control station 40 and the first
`communication line 51. The second communication line 52 may be
`different even if it is the same type of line as the first communication
`line 51, and the first communication line 51 various communication
`lines can be considered.
`
` Special clearing2 — 44929(#)5
`
` From each base station 6,21, B2 22 and B3 2 3, base station information signals 80 including
`base station number 81 as shown in Figure 4 are transmitted sequentially from each base
`station B, 21, B2 22 and B3 23 individually as shown in Figure 5 (a) to (d), and mobile
`station 10 receives signals as shown in Figure 6.
` Figure 7 shows the detailed configuration of the mobile station
`10. Mobile station 10 has antenna 11, mobile 12, telephone 13, positional signal
`detector 14, includes 15 signal array transmitters and 16 modems.
` The position information signal detector 14 receives the
`demodulation signal of the base station information signal 80 from
`the base station to the mobile station 10 from the mobile device 12,
`detects the base station number and the received electric field level
`of the base station information signal transmitted by the base station
`from the demodulation signal 80 and the wave detection output, and
`sends the base station number 81 and the received electric field level
`to the signal array transmitter 15. Signal arrangement transmitter 15
`sends the mobile number and position information of mobile station
`10, i.e. base station number 81 and received field level to modem 16.
`Modems 16 modulates the data signal from signal array transmitter
`15 and sends it to mobile device 12.
` Location Information Center 60 sends location information to
`mobile station 10
`
` At the request of the or when transmitting location information
`from mobile station 10 to location information center 60, position
`information detected by mobile station 10, i.e. base station B, 21,
`base station number 81 such as B 2 22 and B323, received field level at mobile
`station 10, and mobile station number 10 itself. call mobile station 10
`from the location information center 60, or call location
`information center 60 from the location information center 10, and
`send it from mobile station 10 to location information center 60
`through the first communication line 51 set between the location
`information center 10 and location information center 60.
` The location information center 60 receives the mobile station
`number and the location information sent from the mobile station
`10 by the location information transmitting and receiving device
`61 and determines the location of the mobile station 10 by
`comparing the location information with the electric field strength
`map 90.
` Finally, the location information center 60 sends the mobile
`station number and the location of the mobile station to the
`location information receiving device of the location information
`user 70 requesting the location information of the mobile station
`10 through the second communication line 52 from the position
`information receiving device 61.
` By the way, in the configuration of mobile station 10 in Fig.
`7, mobile device 12 originally has a means of detecting the control
`signal and received electric field level, so by changing the
`software of mobile device 12, it is possible to have a mobile
`station 10 with the same means as above, except for modem 16.
`In this case, the position information signal detector 14 and the
`
`signal array transmitter 15 are unnecessary. In addition, if the
`control channel is used to send the mobile station number and
`location information to the base station side, the model 16 is
`unnecessary.
` Figure 8 is a block diagram showing the key parts of the
`mobile communication system based on the second working
`example of the present invention, and Figure 9 is a block diagram
`showing the details of the mobile station.
` In the first example of Fig. 3, the field strength map 90 is
`removed from the location information center 60 and installed in
`the mobile station 10A, and the other examples are the same as
`the first example.
` In this second example, the position detection result at mobile
`station 10A is used on mobile station 10A side, and the position
`detection result at mobile station 10A is sent along with the mobile
`station number to the mobile communication control station 40,
`the location information center, or the location information user
`70.
` Fig. IO and Fig. 11 are block configuration diagrams
`showing the key parts of the mobile communication system
`based on the third and fourth examples of the present invention,
`respectively.
` In the first example of Figure 3, the electric field strength
`map 90 is removed from the location information center 60 and
`installed in the mobile communication control station 40A and the
`location information user 70A respectively.
` In the third and fourth examples, position detection is
`performed at the mobile communication control station 40A and
`
` 11
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` Special clearing2 — 44929(#)6
`
`the location information user 70A, using the position information
`sent from the mobile station 10.
` Figure 12 is a block configuration diagram showing the
`mobile communication system based on the fifth working
`example of the present invention, Figure 13 is an explanation
`diagram showing an example of the channel table, and Figure 14
`is a block configuration diagram showing the details of the
`mobile station.
` In the first example of Figure 3, a channel table 100 is set up
`along with an electric field strength map 90 as the location
`information center 60A, and a receiver 17 and memory 18 are set
`up as the mobile station 10b corresponding to this.
` The first and fourth examples show cases in which base
`station information signals including the base station number are
`transmitted sequentially from each base station, and mobile
`
`stations can detect the level of communication at each base station
`simply by receiving the base station information signal. this
`example uses the method of detecting the reception level of each
`base station even when such a signal is not transmitted from the
`base station. each base station B , 21 B, Haji the base station information
`signal including the base station number is not transmitted sequentially individually
`from 2 3. Here, channel table 100 includes channel number 101 and base station
`number 102, which are associated with the communication channel and the base
`station using the communication channel, as shown in Figure 13.
` In Figure 12, in mobile station 10b, channel number 101 of
`the talk channel where the signal is received and the received
`electric field level at mobile station 10b of the Ji-NEL are stored in
`memory 18 while switching the talk channel sequentially while
`listening.
`
`communication system shown in Figure 2. it detects the received
`electric field level of that channel while switching the
`communication
`channels
`sequentially,
`and
`sends
`the
`communication channel number I and the received electric field
`level of that channel to memory 18 as positional information.
`When the signal array transmitter 15 needs to transmit positional
`information from mobile station 10b, it reads the positional
`information from memory 18, that is, the communication
`channel number 101 and the received field level, and sends it to
`modem 16 along with the mobile station number. The modem 16
`modulates the data signal from the signal array transmitter 15
`
`
`
`
`
`
`
` When there is a request from location information center
`60A to mobile station 10b, or when a location information is
`sent from station 60A to mobile station information center
`60A, the position information detected by mobile station 10b,
`that is, the communication channel number 101 and the
`received electric field level at mobile station 10b of that
`channel and the mobile station number of mobile station 10b
`itself. the location information center 60A calls the mobile
`station 1 hour or calls the location information center 60A
`from the mobile station 10b, and sends it from the mobile
`station 10b to the location information center 60A through the
`first communication line 51 set between the mobile station 10b
`and the location information center 60A. In the location
`information center 60a, the mobile station number and position
`information sent from mobile station 10b are received by the
`location information transmitting and receiving device 61, and
`the communication channel number 101 and channel table 100 in the
`location information are checked, and the base station using the channel
`from the communication channel number 101 is identified. This reveals the
`received field level at the base station and the mobile station of the base station
`transmitting wave.
` Next, the position of the mobile station 10b is determined
`by comparing the received electric field level at the mobile
`station 10b of each base station transmission wave with the
`electric field strength map 90. Finally, the location information
`center 60'a sends the mobile station number and the mobile
`station position from the location information device 61 to the
`location information receiver 71 of the location information
`user 70 requesting the location information of the mobile
`station 10b through the second communication line 52.
` As shown in Fig. 14, the mobile station 1 dish in this
`example is antenna 11, mobile station 12, telephone 13, signal
`array transmitter 15, the receiver 17 includes a modem 16, a
`receiver 17, and a memory 18. the receiver 17 has the means to
`receive all the communication channels used in the mobile
`
` 2 1
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` 2 2
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` Special clearances 2-44929(#)7
`
`Send it to mobile device 12.
` As in the case of the first and fourth examples, mobile device
`12 has the means to receive all the radio channels of the mobile
`communication system shown in Figure 12 and the means to
`detect the received electric field level. Therefore, by changing
`the software of mobile device 12, it is possible to have the same
`means as described above except for modem 16 in one mobile
`station. In this case, receiver 17, memory 18 and signal array
`transmitter 15 are not required. In addition, if the control
`channel is used to send the mobile station number and location
`information to the base station side, the modem 16 is
`unnecessary. However, since the mobile device 12 cannot
`receive
`the signals of
`the control channel and
`the
`communication channel at the same time, control such as
`detecting the received electric field level of the communication
`channel while switching between the control channel and the
`call channel and the call channel as appropriate is necessary so
`that the mobile device 12 can receive the signals of the control
`channel and the call channel.
` By the way, in a mobile communication system where the
`
`communication channel number and base station number
`correspond to each other, the base station transmitting the radio
`wave of the channel can be identified from the communication
`channel number. In a mobile communication system where the
`communication channel is repeatedly used in place like a car
`phone,
`the base station cannot be
`identified from the
`communication channel number alone.
` In such a case, the correspondence between the call channel
`and the base station can be made by the following methods. That
`is, in the configuration of Figure 12, when a call arrives to or
`originates from mobile station 10b, the channel designation signal 110
`as shown in Figure 15 is sent during the control signal from base station B/1
`to mobile station 10b. The mobile station 10b switches the radio channel from the
`control channel to the designated talk channel according to this channel
`designation signal 110. Mobile station number 111 is necessary to confirm that it
`is a channel designated signal to the station, and base station number 112 is used
`in the end signal transmitted from mobile station 10b to base station 8,2I when
`mobile station 10b terminates a call, or in the line disconnect signal transmitted
`from base station B and 21 to mobile station 10b
`
`
`
`
` 2 3
`
` Even so, it is necessary to prevent accidental disconnection of the line
`by being able to distinguish it from the end signal and the line
`disconnection signal for the call channel of the own station.
` In the configuration of Figure 12, as shown in Figure 15, the
`mobile station 10b extracts the base station number 112 from the
`channel designated signal 110 and transmits the base number 112 to
`the location information center 60a along with the multiple received
`call channel numbers and the received electric field level of the
`channel while switching the communication channel sequentially. In
`the position information center 60A, instead of the channel table 100
`in Figure 13, the table shown in Figure 16 corresponds to the base station table
`120, which can select from the base station number 121 of base station B, 21 to the
`neighboring base station B, 21, and the peripheral base station B 2 22 and B 3
`23, etc., and the base station number 132 and the communication channel number 131,
`as shown in Figure 17. With. In the location information center 60A, th