JPH1084571A - Private radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify the current position of a portable terminal equipment correctly. SOLUTION: A private area is divided into a plurality of division areas, a division area ID is assigned to each division area. A repeater is assigned to each division area and the repeaters are connected to a center computer 41. When the center computer 41 enters an identification number of a portable terminal equipment 60, the repeater sends a call signal. The portable terminal equipment 60 responding to the call signal sends a reply signal and it is received by the repeater. Each repeater detects an electric field strength of the reply signal and the detected electric field strength is sent to the center computer 41. A reference electric field strength pattern is registered in the center computer 41 in advance and the location of the portable terminal equipment 60 is located by pattern matching between the reference electric field strength pattern and the electric field strength pattern depending on the electric field strength sent from the repeater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local wireless communication system for specifying the location of a person who carries a portable terminal to a small area.

[0002]

2. Description of the Related Art A position identification system using a PHS (Parsonal Handyphone System) has been proposed as a method for a third party to confirm the location of a communication terminal (the location of a person holding the communication terminal). (For example, NIKK
EI ELECTRONICS 1996.7.15 (no.666) p. 125). This is because a plurality of base stations are arranged at appropriate positions, and the position of the PHS is calculated by the principle of triangulation based on the received electric field strengths of the three base stations, or the position of one base station capable of communicating with the PHS is calculated. The position of the PHS is specified.

When such a position specifying system is used inside a building, a radio wave transmitted from the terminal is reflected by a structure such as a wall. The reflection direction of such radio waves differs depending on the direction, material, and form of the wall. Since the radio wave transmitted by the communication terminal is not always received linearly by one or a plurality of repeaters, there is a possibility that the location specification may be hindered.

[0004]

DISCLOSURE OF THE INVENTION The present invention determines the location where a terminal exists.
It is an object of the present invention to provide a private wireless communication system capable of specifying a narrow range regardless of the presence of a wall or other radio obstacles.

[0005] A private wireless communication system according to the present invention comprises:
It includes a plurality of repeaters that are arranged at a plurality of different places and receive radio waves including at least a terminal identification code transmitted from a portable terminal, and a center device that communicates with the plurality of repeaters.

Each of the above-mentioned repeaters is means for detecting the reception intensity of the radio wave transmitted from the portable terminal, and transmitting the terminal identification code contained in the detected reception intensity and the received radio wave to the center device. 1 transmission means.

[0007] The center device transmits a pre-created reference electric field intensity pattern, which is represented by the reception intensity when a plurality of repeaters receive radio waves transmitted from the mobile terminal, to a plurality of different positions of the mobile terminal. Storage means correspondingly held, a pattern formed by the reception intensity of the transmission radio wave of the portable terminal having the same identification code transmitted from a plurality of repeaters, and a plurality of references stored in the storage means Means for comparing with an electric field intensity pattern to identify a position where the portable terminal exists.

In the center-led system, the repeater is provided with a second transmission means for transmitting a call signal including at least a terminal identification code in response to a command from the center device. The portable terminal transmits a response signal in response to the calling signal. The repeater receives the response signal transmitted from the portable terminal and detects the reception strength.

This system is generally constructed inside a building or a facility. A space where the portable terminal can exist is divided into a plurality of divided areas, and an area number is assigned to each divided area. The location of the portable terminal can be specified using the area numbers assigned to the plurality of divided areas. The division area is a unit for specifying the position of the portable terminal. It is preferable that the reference electric field intensity patterns are regarded as substantially the same within one divided area. Preferably, one repeater is provided in one divided area, but this is not necessary.

[0010] The portable terminal is carried by the user.
An identification code (number) is assigned to the mobile terminal. Employee numbers, telephone numbers, and other numbers are used as the identification codes.

A reference electric field intensity pattern is created in advance for each of a plurality of different positions (preferably, for each representative point of the divided area), and is held in the center device.
In a preferred embodiment, the center device is provided with means for creating a reference electric field intensity pattern based on the reception intensities transmitted from the plurality of repeaters in the reference electric field intensity pattern generation mode.

According to the present invention, a radio wave transmitted from a portable terminal is received by a plurality of repeaters, and the reception strength is measured. The measured reception intensity is sent to the center device. In the center device, the pattern formed by these reception intensities is compared with a plurality of reference electric field intensity patterns, and it is determined that the position of the most similar reference electric field intensity pattern is the position of the portable terminal.

The reference electric field intensity pattern is created by reflecting the propagation characteristics of radio waves in the area. Therefore, the presence of a radio wave obstacle such as a wall is considered in the reference electric field intensity pattern. By pattern matching using the reference electric field strength pattern, regardless of the presence of radio obstacles such as walls
The position of the mobile terminal can be accurately specified to a relatively narrow range.

[0014] In one embodiment, a switching device is provided in the repeater for switching the received radio wave from the portable terminal to at least two levels. The repeater detects at least two levels of reception strength and transmits the reception strength to the center device. The above-mentioned center device holds a reference electric field intensity pattern of at least two levels of reception intensity.
The position where the portable terminal exists is identified based on one of the reference electric field intensity patterns.

When the portable terminal is near the repeater, the circuit of the repeater may be saturated and the reception intensity may not be detected correctly. Also, when the portable terminal is far from the repeater, the reception strength may be low.

In this embodiment, the repeater receives radio waves from the portable terminal at at least two levels,
Since pattern matching is performed for these two levels, the degree to which either of the reference electric field intensity patterns matches increases, and more accurate position detection becomes possible. A reception level switching means may be provided so that the repeater can detect three or more levels of reception intensity such as strong, medium, and weak. In this case, the center equipment is strong, medium,
A reference electric field intensity pattern of reception intensity of three or more weak levels is held, and the location of the portable terminal is detected based on one of the reference electric field intensity patterns.

In still another embodiment, the center device holds a reference electric field intensity pattern of the reception intensity in a plurality of directions of the portable terminal. The position where the portable terminal exists is specified based on the reference electric field intensity pattern in any one direction.

The intensity of the radio wave received by the repeater changes depending on the orientation of the portable terminal. In this embodiment, since a reference electric field intensity pattern is created in advance for one position in a plurality of directions of the portable terminal, the position can be specified without being affected much by the direction of the portable terminal.

More preferably, the reference electric field intensity pattern held in the center device is created by normalizing the measured values. As a result, correct position detection can be performed without being significantly affected by fluctuations in radio wave intensity due to fluctuations in radio wave voltage or the like of the portable terminal.

The position of the portable terminal specified in this way is output (for example, displayed) in the center device.

In still another embodiment, means for detecting the maximum reception strength among the reception strengths transmitted from the plurality of repeaters and selecting the repeater which has transmitted the maximum reception strength is provided to the center device. Provided. Communication between the portable terminal and the center device is performed via the selected repeater. In this way, communication using the portable terminal can be performed through the relay having the highest sensitivity.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS This local wireless communication system comprises a single control center, a plurality of repeaters provided at appropriate places in the local premises, and a portable terminal carried by a user. The purpose of use of this private wireless system is to locate a user who is carrying a portable terminal and is somewhere in the premises. If you know where the user is,
Communication (including conversation) between the user's portable terminal and the control center via a repeater nearby
Becomes possible. Further, communication between the portable terminals, connection between the portable terminals and external lines, and the like can be performed via the repeater and the control center. However, when the user makes a call from the portable terminal to the control center, the control center does not necessarily need to locate the portable terminal.

Therefore, there are the following two usage modes of the private wireless communication system.

One is that when the control center calls the portable terminal, the location of the portable terminal is specified to a narrow range, and this is displayed on the display screen of the control center (this is called position (Specific mode)
It is.

The second is a mode in which communication such as a call is performed between portable terminals or between the portable terminal and the control center via a repeater of the relay base station (this is called a call mode).

In this private wireless communication system, each portable terminal is assigned a different identification number in advance, and this is stored in the memory of the portable terminal. Similarly, different identification numbers are assigned to the repeaters and are stored in advance in the memory of the repeater.
Further, the place where the repeater is installed (the position of the relay base station) is known by the control center.
That is, the installation location of the repeater is registered in the memory of the center computer (described later) of the control center corresponding to the identification number of the repeater. These data can be rewritten according to an increase or decrease of the portable terminal or the repeater (relay base station).

In the position specifying mode, the reference electric field intensity pattern created and registered in advance and the electric field intensity of the radio wave (response signal) transmitted by the portable terminal in response to the call signal and received by a plurality of relay base stations. By performing pattern matching with the pattern, the position of the portable terminal is specified. Radio waves transmitted from the portable terminal are reflected or attenuated by the walls of the building and other obstacles. Since the reference electric field intensity pattern reflecting the propagation characteristics of the radio wave in the premises including such obstacles is created and registered in advance, the position of the portable terminal can be accurately specified. In the call mode, the repeater having the highest reception intensity of the radio wave transmitted from the portable terminal (usually at the position closest to the portable terminal) relays the communication.

The reference electric field intensity pattern is a pattern in which electric waves are transmitted from a predetermined place in the premises and the electric field intensity levels of the electric waves received by the respective relay base stations are represented in a table form, which will be described in detail later. A plurality of reference electric field intensity patterns corresponding to a plurality of locations are stored in the center computer of the control center in advance.

FIG. 1 shows an example of a spatial arrangement of a private wireless communication system, and shows a part of one floor inside a building.

The private wireless communication system is constructed over a suitable area. The range in which this system is constructed may be the entire building, or may be limited to one floor of the building or a part of the premises. Private wireless communication systems are portable terminals owned by users who move within the range.
60 (indicated by x in the figure), and repeaters 11, 12, 13, 14, 15, 16, 21, 22, and 2 installed at relay base stations installed in appropriate locations
3, 24, 31, 32, 33 and 34 (indicated by ○ in the figure) and a control center 40 (see FIG. 2) to which all repeaters are connected. If a relay base station can be installed, an indoor wireless communication system can be constructed even outdoors such as an amusement park. The repeater is preferably a structure related to a building, such as a ceiling, a wall, or a floor under the building,
It can be installed on premises such as telephone poles and street lights. of course,
A repeater can be installed on a dedicated support tower.

In any case, the range in which the private wireless communication system is provided is divided into a plurality of areas. The divided area is a unit for specifying the position of the portable terminal, and is defined as having a desired size. FIG.
, Each divided area is indicated by a chain line. One room forms one divided area. Areas of complex shape, such as corridors and associated elevator halls,
It is divided into a plurality of divided areas. These divided areas have different identification codes (hereinafter, divided area IDs).
Has been assigned. In FIG. 1, these divided area IDs are represented by a1 to a13.

Preferably, at least one repeater is installed in one divided area. If there is no problem in specifying the location of the mobile terminal, the number of repeaters can be set smaller than the number of divided areas, and when more precise and detailed location of the mobile terminal is required, May be provided with a plurality of repeaters in one area. In any case, the installation position and the number of the repeaters are reflected in the reference electric field intensity pattern, and affect the accuracy of specifying the position of the portable terminal. The installation position of the repeater is also determined from the viewpoint of whether communication between the portable terminal and the repeater can be performed well.

In FIG. 1, one repeater is provided in one divided area. In the following description, reference numerals 11 to 16, 21 to 24, and 31 to 34 of each repeater are used as identification numbers (base station numbers) assigned to those repeaters for convenience.

FIG. 2 shows an example of the electrical configuration of the private wireless communication system.

In a preferred embodiment, the control center 40 of the private wireless communication system includes a center computer 41 to which an internal memory 42, an external memory 43, an input device 44 and an output device 45 are connected. ing. The plurality of repeaters 11 to 13... N are connected to a center computer 41 of a control center 40. The control center 40 has a private branch exchange.
46 are provided. This private branch exchange 46 is
Under the control of the computer 41, a connection between repeaters or between a repeater and an external telephone line is made.

The input device 44 is for inputting the identification numbers of the portable terminals 60 individually when calling the portable terminal 60, and includes a keyboard, a mouse, a touch panel type display and the like. The input device 44 is also used for inputting information such as installation location information of each repeater. The output device 45 mainly outputs the location information of the portable terminal 46.
Includes RT display devices and printers. By displaying a menu screen on the CRT display device or providing a touch panel on the display screen of the CRT display device, the CRT display device may have some or all of the functions of the input device. The internal memory 42 stores the program of the center computer 41, the identification number of the repeater, its installation location information and the portable terminal.
Stores 60 identification numbers and includes work areas for various processes (pattern matching using a reference electric field intensity pattern, etc.). The external memory 43 is a portable terminal
It stores the field strength data and the like of the response signal transmitted from 60 and received by the repeater. The identification number of the program, the repeater, the installation location information thereof, and the identification number of the portable terminal 60 may be stored in the external memory 43.

The installation location information indicates at least the correspondence between the repeater and the divided area (including its name), and preferably includes a drawing showing the divided area as shown in FIG. After transmitting the call signal to the desired portable terminal, the operator of the control center 40 confirms the location of the called portable terminal by looking at the drawing as shown in FIG. 1 displayed on the CRT display device. be able to.

The repeater relays the communication between the portable terminal 60 and the center computer 41, and
A wireless communication circuit for communicating with the wireless communication with the center 60 and a wired communication circuit for communicating with the center computer 41 through a transmission line are provided. The wireless communication circuit includes a transmitting circuit for transmitting a calling signal to the portable terminal 60 and a receiving circuit for receiving a response signal from the portable terminal 60.

When a call signal is transmitted from the center computer 41, the repeater transmits radio waves to the surroundings. When receiving the radio wave from the repeater, the portable terminal 60 transmits a response signal including at least the identification number of the portable terminal in response to the received radio wave. The repeater that has received the response signal from the mobile terminal 60 transmits the information included in the response signal and the information indicating the electric field strength of the response signal to the center computer 41.

In this private wireless communication system, the electric field strength of the response signal from the portable terminal 60 is used in both the position specifying mode and the call mode. The electric field strength of the response signal is detected in the repeater that has received the response signal.

FIG. 3 shows a receiving circuit included in the wireless communication circuit of the repeater. Input voltage switching circuit 50
And a processing circuit 54. The processing circuit 54 is connected to the center computer 41 via a wired communication circuit (not shown).

The input voltage switching circuit 50 comprises resistors 51 and 52 and a switch 53. The changeover switch 53 is
Controlled by a semiconductor control circuit (not shown) under the control of the processing circuit 54 (or the center computer 41), the switching of the A terminal and the B terminal of the changeover switch 53 is performed for a predetermined time after the repeater transmits a calling signal. Done at intervals. It is preferable that the changeover switch 53 is always connected to the A terminal.

When the changeover switch 53 is connected to the A terminal,
The response signal received by the antenna is supplied to the processing circuit 54 via the changeover switch 53 (this is called strong level reception). When the changeover switch 53 is connected to the terminal B, a part of the response signal received by the antenna is divided by the resistors 51 and 52 and given to the processing circuit 54 (this is called weak level reception). In this way, the response signal from the portable terminal 46 is received at two levels, strong and weak.

The processing circuit 54 has an AGC (Automatic Gain C)
ontrol: automatic gain control device), detection circuit, A / D (Anal
og / Digital) conversion circuit, a signal strength meter (S meter), and the like. The response signal from the portable terminal 60 is amplified by the AGC and then detected by the detection circuit. The detected analog signal is further converted to a digital signal by an A / D conversion circuit. The output of the AGC is also input to the S meter, and the signal strength (electric field strength) of the received response signal is detected by the output of the S meter. In this way, the content of the response signal received by the repeater and the signal strength (both strong and weak levels) are sent to the center computer 41.

FIG. 4 is a graph showing the relationship between the electric field strength of the response signal transmitted by the portable terminal and the received electric field strength of the response signal received by the repeater.

In the local wireless communication system, the location of the portable terminal is specified in the position specifying mode by using the electric field strength of the response signal from the portable terminal, and the relay for performing data communication or the like in the call mode. The machine is selected. Therefore, it is necessary that the received signal strength of the repeater correctly corresponds to the electric field strength near the place where the repeater exists. However, generally, as shown in FIG. 4, when the electric field strength of the radio wave transmitted from the portable terminal is strong (when the portable terminal is near the repeater), the reception level is saturated.

As described above, the input voltage switching circuit 50 is provided, and the repeater has two reception sensitivities of strong and weak levels.
These are alternately switched. Since two types of electric field intensity data of the strong and weak levels obtained from the repeater are sent to the center computer 41, the center computer 41 can use any of these electric field intensity data. It can be considered that either one of the electric field strength data correctly represents the electric field strength near the repeater.

FIG. 5 shows the electrical configuration of the portable terminal. The portable terminal device 60 includes a control device 61, a receiving circuit 62, a transmitting circuit 63, a calling device 64, an input device 65, a communication device 66, and a memory 67.

The operation of the portable terminal is controlled by the control device 61. The control device 61 includes a central processing unit and its input / output interface circuit. The interface circuit includes an A / D converter, a D / A converter, and the like. The central processing unit is realized by a programmed computer (especially a microprocessor). The memory 67 stores an identification number of the portable terminal 60, a program for controlling the processing operation of the central processing unit, and the like.

When receiving the radio wave from the repeater, the receiving circuit 62 passes the information contained therein to the central processing unit. The information passed from the receiving circuit 62 to the central processing unit includes a call signal when the control center 40 or another portable terminal calls the portable terminal 60, and a call signal when the control center 40 or another portable terminal 60 is called. , Etc. in the communication (conversation) state. The operation of the portable terminal 60 is controlled by the central processing unit according to this information. The receiving circuit 62 includes a circuit for demodulating a received signal and a circuit for decoding.

The transmitting circuit 63 includes a signal responding to the calling signal received by the receiving circuit 62 and an input device 64 of the portable terminal 60.
And transmits a signal or the like representing the information input from the relay device to the repeater. The transmission circuit 63 includes a circuit for encoding a transmission signal, a circuit for modulating, and the like.

The paging device 64 responds to a paging signal to notify the user of the paging signal, and includes a vibration device or a ringing tone generator (such as a buzzer). When the calling device 64 operates, the user of the portable terminal device 60 uses the input device 65 to input an intention to respond to the call. In the case of communication between the control center 40 and the portable terminal 60 in the call mode and communication between portable terminals, the calling device 64 is used.
Should work. In the position specifying mode, the calling device 64 does not always have to operate because it is not necessary to recognize that the user carrying the portable terminal device 60 has been called.

The input device 65 is used to display a will to respond to the call of the portable terminal 60, input an identification number when calling another portable terminal, and input other information. including. The user of the portable terminal 60 recognizes that the portable terminal 60 owned by the user is called by the ringing sound of the calling device 64 as described above. When the user inputs an intention to respond from the response button, a response signal is transmitted via the transmission circuit 63. To call another mobile terminal, use the numeric keypad to call the other mobile terminal.
Enter the identification number of 60. A radio wave including the information of the input identification number is transmitted from the transmission circuit 63.

The communication device 66 is used when a conversation is performed using the portable terminal device 60, and includes a speaker, a microphone, and the like.

As described above, this private wireless communication system has two modes: the position identification mode and the call mode. In the position specifying mode, pattern matching between the reference electric field intensity pattern registered in advance and the measured electric field intensity pattern is performed, whereby the position of the portable terminal 60 is specified. Therefore, in order to operate this system, it is necessary to create a reference electric field intensity pattern in advance.

FIG. 6 is a flowchart showing the procedure for creating and registering the reference electric field intensity pattern in the center computer 41 of the control center. In the following description, reference is made to an example of the arrangement of the private wireless communication system shown in FIG.

The divided area is determined within the range of use of the private wireless communication system. The divided area is determined based on the idea of a person (including a user) who constructs this private wireless communication system. Output device of control center 40
The location of the portable terminal 60 output from the unit 45 is in units of the divided area determined here. In the example shown in FIG. 1, 13 divided areas of each of the rooms 1 to 10, the elevator hall, the corridor A, and the corridor B are set. A divided area ID is assigned to each divided area, and the location of the portable terminal 60 is basically specified using the divided area ID. Of course, a name (for example, room 1, elevator hall, corridor A, etc.) corresponding to each divided area ID may be determined in advance, and the position of the portable terminal 60 may be grasped using this name.

The repeaters are arranged according to the divided areas thus set. Preferably, one repeater is placed in one divided area as described above. Since the repeater communicates with the portable terminal 60 at an arbitrary position within the range where the private wireless communication system is constructed, at least the radio wave transmitted from the portable terminal 60 within the range is transmitted. It is necessary to install one repeater so that it can receive at a reception level of at least a certain value. In the case of the embodiment shown in FIG. 1, the repeaters 11 to 11 are provided one by one for each divided area divided into 13.
16, 21 to 24 and 31 to 34 are installed. of course,
At the stage where this system is actually used, if there is a place where communication between the center computer 41 and the portable terminal 60 does not work well, repeaters will be added at or near that place, On the other hand, if you find that it is installed extra, you can reduce the number of repeaters installed.

The arrangement information of the repeater, such as the identification number of the repeater, the divided area ID of the divided area in which each repeater is installed, and the information on the installation location of the repeater, is input to the center computer 41. These pieces of information are stored in the internal memory 42 of the center computer 41 (step 101).

The portable terminal 60 is brought to a representative place in one divided area, and a response signal is transmitted from the portable terminal 60 there (step 103). Center computer 41
A response signal may be transmitted from the mobile terminal 60 in response to a call signal from the mobile terminal 60, or may be voluntarily transmitted from the mobile terminal 60 for the purpose of creating a reference electric field intensity pattern irrespective of the call signal from the center computer 41. May transmit a response signal.

The response signal is received by one or a plurality of repeaters around the portable terminal 60. The reception strength of each repeater that received the response signal is
The data is transmitted to the computer 41. Center computer 41
In step (1), a table representing the electric field strength of the response signal received by each repeater is created, and a reference electric field intensity pattern is created based on this table (step 104). The measurement of the reception strength in the repeater is performed by switching the switch 53 of the input voltage switching circuit 50 in the repeater between high-level reception and low-level reception, and changing the direction of the portable terminal 60 in four directions at each reception level. , At least eight times in total. The switching between the high level reception and the low level reception is performed by the processing circuit 54 (or the center computer 41) of the repeater as described above. The portable terminal 60 sends the response signal continuously or intermittently many times.

FIG. 7 shows a case where a response signal is transmitted from the portable terminal 60 at a point indicated by a cross in FIG. 1 (divided area ID: a12), and an electric field strength table (FIG.
(A)) and a reference electric field intensity pattern created based on this table (FIG. 7 (B)).

In the table shown in FIG. 7A, the electric field strength (db value) detected by each repeater is entered.
As described above, if the electric field strength of the response signal from the portable terminal 60 is strong, the reception level of the repeater is saturated. Therefore, the input voltage switching circuit 50 provided in each repeater performs the reception of the strong level. The electric field intensity is measured at two reception levels of the weak level reception, and a table including both measurement results is created.

Further, the measurement of the reference electric field strength is performed when the portable terminal 60 is directed in each of four directions a, b, c and d (see FIG. 1) at one measurement point. The measured electric field strength values are shown in a table. The orientation of the portable terminal is not limited to the illustrated a to d but may be any direction, and the number is not limited to four.

The mobile terminal used in the private wireless communication system is most commonly used in a user's breast pocket. Even when the response signal is transmitted from the same place, the electric field strength of the received signal received by each repeater differs depending on the body direction. By measuring the electric field strength in multiple directions at one point, various propagation characteristics of the response signal are registered as the reference electric field strength pattern, so that more accurate portable terminal
60 locations can be identified. Of course, the same result will be obtained in the case of another portable mode of the portable terminal (for example, a state in which the portable terminal is put in the bag), and the position can be specified.

Preferably, as shown in FIG.
The pattern obtained by modifying the measured electric field strength based on the maximum electric field strength value in each reception direction at the weak reception level is defined as a reference electric field strength pattern. For example, in the a-direction of the strong level reception, since the maximum electric field strength (18 db) is received in the repeater of the base station number 32, the reception electric field strength of each repeater in the a-direction of the strong level reception is calculated as “ 18 "respectively (normalize, which means take the ratio because it is a db value). Similarly, since the reception strength (16 dB) of the repeater of the base station number 32 in the weak level reception b direction is the maximum, “1” is obtained from the reception electric field strength of each repeater in the weak level reception b direction.
6 "is subtracted. As a result, even when the output of the response signal of the portable terminal device 60 varies due to a decrease in the battery voltage or the like, the variation in the absolute value is corrected.
Matching can be performed more accurately. of course,
The table shown in FIG. 7A may be used as the reference electric field intensity pattern.

The above-described measurement is repeated while changing the position of the portable terminal 60 (at least one location in one divided area) (step 102). By registering more reference electric field intensity patterns, the position of the portable terminal 60 can be specified with higher accuracy.

The reference electric field intensity pattern thus created corresponds to the information (for example, the divided area ID) indicating the position of the portable terminal used for the pattern creation.
The information is registered in the internal memory 42 of the control center 40 (step 105), and the process of creating and registering the reference electric field intensity pattern ends.

The position of the portable terminal 60 is specified by using the reference electric field intensity pattern thus created.
This is done by matching. At the same place or near the place where the response signal was sent when creating the reference electric field strength pattern, the portable terminal was used when the actual system was used.
60 sends a response signal. The electric field strength is measured by a plurality of repeaters. Since the electric field intensity pattern obtained from this measurement result is substantially the same as any one of the plurality of reference electric field intensity patterns, the position stored corresponding to the reference electric field intensity pattern determined to be the same is determined by the portable terminal. The location of the aircraft is determined.

FIGS. 8 and 9 show the processing procedure of the center computer when the private wireless communication system actually moves. FIG. 8 shows a processing procedure in the position identification mode, and FIG. 9 shows a processing procedure in the call mode.

First, either the call mode or the position specifying mode is selected (step 111). The selection of the call mode and the position identification mode is basically performed by the operator in the control center 40. When one mobile terminal 60 calls another mobile terminal and performs communication (data communication, conversation, etc.), the request from the one mobile terminal 60 is controlled via the repeater.
The communication mode is transmitted to the center 40, and the communication mode is automatically selected in the control center 40. In the case of a connection from the telephone network, the communication mode is selected by the control center 40 in response to a connection request given via the exchange 46.

The position specifying mode will be described. The operator selects the position specifying mode using the input device 44 connected to the center computer 41 (step 11).
1), the identification number of the portable terminal 60 whose position is to be specified is input (step 112). When the identification number is input, a transmission message including the input identification number and indicating the position identification mode is given to all the repeaters. A call signal including the identification number and indicating the location specifying mode is transmitted from the repeater.

If a paging signal is simultaneously transmitted from many repeaters installed close to each other, these radio waves may interfere with each other and cause a reception failure. In order to prevent such a reception failure, the repeaters may be divided into several groups, and a paging signal may be transmitted for each group. In this grouping, it is preferable that repeaters existing at a distance apart from each other so as not to cause a failure belong to one group. The presence of a wall material or the like that blocks radio waves will also be considered when performing grouping.

Upon receiving the call signal, the portable terminal 60 determines whether or not the identification number included in the call signal matches its own identification number (stored in the memory 67 in advance). Step 113)). The portable terminal 60 that has received the call signal including the identification number that matches the identification number of the terminal transmits a response signal including the identification number of the terminal. When receiving a call signal including an identification number that does not match its own identification number, the portable terminal 60 does nothing.

The response signal from the portable terminal 60 is received by one or more surrounding repeaters. Upon receiving the response signal, the repeater detects the identification number of the portable terminal and the electric field strength of the response signal included in the response signal (step 114). The electric field strength of the response signal received by each repeater is sent to the center computer 41 together with the identification number of the portable terminal extracted from the response signal, and a measured electric field strength pattern is created (step 115).

The portable terminal 60 transmits the response signal continuously or intermittently a plurality of times in response to the reception of the call signal. The repeater receives these response signals in both high-level reception and low-level reception while switching the changeover switch 53. As a result, the reception electric field strength of the strong level reception and the reception electric field strength of the weak level reception can be obtained.

When the portable terminal 60 receives the call signal indicating the position specifying mode, the portable terminal 60 does not operate the call device 66.

The electric field strength of the response signal detected in each repeater and the identification number of the portable terminal are preferably determined by group-based separation polling to obtain the center computer 41.
Transmitted to In this method, the center computer 41 sequentially asks each repeater for the presence or absence of a transmission request for each group, and permits transmission to the repeater having the transmission request. The repeaters belonging to the same group are simultaneously called for a transmission request. Each repeater sequentially transmits the detected received electric field strength and the identification number of the portable terminal to the center computer 41 in response to the call from the center computer 41.

FIG. 10 shows an example of a measured electric field intensity pattern created in the center computer 41.

The center computer 41 divides the reception field strength data transmitted from the repeater having the same portable terminal identification number as the identification number input in step 112 into strong and weak reception levels. , Create a table.
In this table, the one having the maximum strength is found for each of the strong and weak reception levels, and this maximum strength is subtracted from each of the received electric field strengths. The resulting electric field strength pattern (FIG. 10) is thus obtained.

The measured electric field intensity pattern created in this way is compared with a reference electric field intensity pattern stored in the internal memory 42 in advance by a pattern matching method, and a reference electric field pattern having a pattern closest to the measured electric field intensity pattern is compared. An electric field strength pattern is determined (step 11)
6). It goes without saying that this pattern matching process is performed for each of the data of the strong level reception and the data of the weak level reception.

The pattern matching can be performed by various known methods. For example, for each repeater, the absolute value (or the square of the difference) between the electric field intensity in the reference electric field intensity pattern and the electric field intensity in the measured electric field intensity pattern is calculated, and the sum of them is calculated. The one with the smallest sum is the reference electric field intensity pattern that matches the most.
A fuzzy pattern matching technique can also be employed.

When a reference electric field intensity pattern that best matches the measured electric field intensity pattern is found, information indicating the position of the portable terminal (for example, a divided area ID) stored corresponding to the reference electric field intensity pattern indicates the position. The position of the portable terminal 60 to be specified is output and displayed on the output device 45 such as a CRT display device (step 117).

In the position specifying mode, the position of the portable terminal 60 can be specified at least up to the range defined by the divided area. For example, when transferring an outside line call to an extension line, instead of calling the person called by the in-house broadcast, etc., first check the location of the portable terminal possessed by the person, and close to the place where the person is located. An external telephone can be transferred to an extension telephone (repeater). If the person making the call from outside can know the identification number of the portable terminal in advance, the identification number is transmitted to the center computer 41, so that the calling party can be most often called without passing through the operator of the center computer 41. It is also possible to automatically transfer an external telephone to a nearby internal telephone and connect it. As a result, even if the mobile terminal 60 does not have the call mode function,
It can be used in almost the same form as a portable terminal having a call mode function. In this case, since the part of the call mode function can be omitted from the portable terminal 60, the weight and thickness of the portable terminal 60 can be reduced.

Next, the talking mode will be described. FIG.
In FIG. 8, the same processes as those shown in FIG. 8 are denoted by the same reference numerals, and overlapping detailed description will be omitted.

When the call mode is selected by the operator and the identification number of the portable terminal 60 is input, the portable terminal 60 having that identification number is called (steps 111 and 11).
2, 113). When the portable terminal 60 receives the call signal in the call mode from the repeater, the portable terminal 60 transmits a response signal. Calling of the portable terminal in the call mode can be performed using the input device 65 of another portable terminal.

In the case of the call mode, the user of the called portable terminal device 60 needs to recognize that the call has been made. Upon receiving the call signal in the call mode, the calling device 64 of the portable terminal 60 operates. The user recognizes that the portable terminal 60 held by the user is being called by a ringing tone, vibration, or the like.

The called user uses the input device 65 of the portable terminal 60 to input a reply to the call. In response to the reply input, a response signal is transmitted from the portable terminal 60,
One or more repeaters around the portable terminal 60 receive this response signal. The repeater that has received the response signal detects the electric field strength of the response signal. The electric field strength of the response signal received by each repeater is given to the center computer 41 (step 114).

In the center computer 41, among the repeaters that have received the response signal, the repeater that has received the radio wave with the maximum electric field strength is selected. The repeater selected by the center computer 41 continues the relay operation, and the other repeaters return to the standby state. Via the selected repeater,
Signal transmission / reception (data communication, conversation, etc.) between the called portable terminal and the called control center 40 or the called portable terminal and the called other portable terminal is performed (step 125). .

[Brief description of the drawings]

FIG. 1 shows a spatial arrangement of a private wireless communication system.

FIG. 2 shows an electrical configuration of a private wireless communication system.

FIG. 3 shows an electrical configuration of a receiving circuit of the repeater.

FIG. 4 is a graph showing the relationship between the electric field strength of a response signal transmitted by a mobile terminal and the reception level of a repeater receiving the response signal.

FIG. 5 is a block diagram illustrating an electrical configuration of the portable terminal.

FIG. 6 is a flowchart showing a procedure for creating a reference electric field intensity pattern.

FIG. 7A shows a table of electric field intensity measured by the repeater, and FIG. 7B shows a reference electric field intensity pattern created based on FIG. 7A.

FIG. 8 is a flowchart illustrating a procedure of a communication process in a position specifying mode.

FIG. 9 is a flowchart illustrating a procedure of a communication process in a call mode.

FIG. 10 shows an example of a measured electric field intensity pattern.

[Explanation of symbols]

 11 ... 16, 21 ... 24, 31 ... 34 Repeater 40 Control center 41 Center computer 42 Internal memory 43 External memory 44 Input device 45 Output device 50 Input voltage switching circuit 51, 52 Resistance 53 Switching Switch 54 Processing circuit 60 Mobile terminal 61 Control device 62 Receiving circuit 63 Transmitting circuit 64 Calling device 65 Input device 66 Communication device 67 Memory

Claims (8)

[Claims] 1. A plurality of repeaters arranged at a plurality of different places and receiving radio waves including at least a terminal identification code transmitted from a portable terminal, and a center device communicating with the plurality of repeaters. Each of the above repeaters includes means for detecting the reception intensity of radio waves transmitted from the portable terminal;
First transmitting means for transmitting the detected reception strength and a terminal identification code included in the received radio wave to the center device, wherein the center device transmits radio waves transmitted from the portable terminal to a plurality of repeaters. Storage means for holding a pre-created reference electric field intensity pattern, represented by the reception intensity at the time of reception, corresponding to a plurality of different positions of the portable terminal; and the same identification transmitted from a plurality of repeaters Means for identifying the position where the portable terminal is present by comparing a pattern formed by the reception intensity of the transmitted radio wave of the code portable terminal with a plurality of reference electric field intensity patterns held in the storage means A private wireless communication system comprising: 2. The portable telephone according to claim 2, wherein said repeater has a second transmitting means for transmitting a call signal including at least a terminal identification code in response to a command from said center device. The private wireless communication system according to claim 1, wherein the repeater receives a response signal transmitted from the terminal, and detects the reception strength. 3. The relay device according to claim 1, wherein the repeater has switching means for switching a radio wave received from the portable terminal to at least two levels, and detects at least two levels of reception intensity and transmits the level to the center device. The center device holds a reference electric field intensity pattern of reception intensity of at least two levels, and specifies a position where the portable terminal exists based on one of the reference electric field intensity patterns. The private wireless communication system according to claim 1 or 2, wherein: 4. The center device holds a reference electric field intensity pattern of reception intensity in a plurality of directions of the portable terminal, and the portable terminal operates based on the reference electric field intensity pattern in any one of the directions. The private wireless communication system according to any one of claims 1 to 3, wherein the location is specified. 5. The apparatus according to claim 1, wherein said center device further comprises means for outputting the specified position of said portable terminal.
The private wireless communication system according to any one of claims 1 to 4. 6. The apparatus according to claim 1, wherein said center device has means for creating a reference electric field intensity pattern based on reception intensities transmitted from the plurality of repeaters in a reference electric field intensity pattern generation mode. The private wireless communication system according to claim 1. 7. The private wireless communication system according to claim 6, wherein said creating means creates an electric field intensity pattern by normalizing the reception intensity transmitted from said repeater. 8. The portable device, comprising: means for detecting a maximum reception intensity among reception intensities transmitted from a plurality of repeaters, and selecting a repeater that has transmitted the maximum reception intensity, The private wireless communication system according to any one of claims 1 to 5, wherein communication between a terminal device and the center device is performed via a selected relay device.