JPS62230232A - Private branch radio call system - Google Patents

Abstract

PURPOSE:To attain a radio call service without crosstalk by allowing each of radio call controllers to reference predetermined information as to the installed relation of position so as to control the sending timing of a radio call signal. CONSTITUTION:When a user in a premises dials a special number from a private branch telephone set TA, a special trunk circuit device 4 of a PBX l is caught. The special trunk circuit equipment 4 is coupled with a radio call controller 7-l of a center. The radio call controller 7-l of the center sends radio call control incormation including a called radio terminal number and a call telephone number by means of the dialing of the special dial to other radio call controllers 7-3,7-4,7-7 via a communication cable 8 in a multiple address communication form simultaneously. The radio call controllers 7-l,7-3,7-4,7-7 start coupled radio transmitters 10-l-10-4 and send the terminal call by a weak radio wave. In this case, the radio transmissioin radio wave sent from nearby radio transmitters depending on the mutual position is sent while not being overlapped timewise.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention' relates to a premises radio paging system that uses weak radio waves, and is particularly designed to prevent a single radio transmitter from covering a wide range of radio paging areas. The present invention relates to a campus wireless paging system that can be applied even in large campuses.

[Conventional technology]

Traditionally, radio paging systems (,
, 11-Ring system) is connected to a private branch exchange (hereinafter abbreviated as PBX), and a wireless calling mobile terminal of the other party is connected by dialing the private branch telephone. A method is known in which an incoming call is displayed at the nearest P'BX, and the called party directly talks to the caller from the nearest P'BX. The traditional method is
It has already been put into practical use and is widely used.

FIG. 4 is a block diagram showing the configuration of a conventional local area wireless paging system. In the figure, 1 is a PBX, 2 is a wireless paging center device, 3 is an antenna for radiating a wireless paging signal into the air, 4 is a special trunk circuit device for coupling the PBX1 to the wireless paging center device 2, and 5-1 .5
-2 are private telephones TA, TB, 6-1, 6, respectively.
-2 are radio calling mobile terminals P and Py, respectively.

FIG. 5 is a diagram showing an example of a control information format for selectively calling a radio calling mobile terminal from the radio calling center device of FIG. 4.

Next, the operation of the conventional private wireless paging system shown in FIG. 4 will be explained. First, the private telephone TA5-1
By turning the special number dial of the PBXI, it is connected to the special trunk circuit device 4. Further, an address assigned to the radio paging mobile terminal to be called, for example, the radio paging mobile terminal Py6-2 shown in FIG.
and the caller's local telephone number (in the example shown in FIG. 4, the local telephone number of private telephone TA5-1), sends the dialing information, once on-hook the private telephone TA5-1, and then calls the other party. Wait for the called party to call you.

The above dialing information is transmitted to the radio paging center device 2 via the special trunk circuit device 4, but in this radio paging center device 2, the radio paging mobile terminal Py6
-2's called wireless terminal number, the calling telephone number of the local telephone TA5-1 that requested the wireless call, necessary additional information such as an error detection code trailer, etc. -2 signal reception operation a5!
For the purpose of standardization, a preamble is added to the beginning, and the data is converted into serial data having the control information format shown in FIG. 5, for example. Subsequently, a radio transmitter (not shown) of the radio call center device 2 modulates a radio carrier wave with the serial data, and the modulated data is transmitted from the antenna 3 as a weak radio wave.

In the radio calling mobile terminal Py6-2.

Only the signal that matches the own address is detected as being significant, and at the same time the dial number of the local telephone TA5-1 that made the call is also displayed. Radio paging mobile terminal Py6-2
A subscriber carrying a mobile terminal Py6-2 sees the incoming call display signal (usually also notified by an audible signal) and calls from the nearest telephone to the mobile terminal Py6-2 that made the radio call. The private telephone TA5-1 displayed in
Dial the Densan number and make a voice contact call.

[Problem that the invention seeks to solve]

In the conventional in-premises wireless paging system as described above, the in-premises service area becomes wider because the wireless transmitter transmits the wireless paging signal from a single wireless transmitter integrated into a central PBXI or the like.

Since the wireless transmission power uses weak radio waves, which are legally restricted by the Radio Law, there is a problem in that the wireless paging signal may not reach the called party. .

This invention was made in order to solve such problems, and is an in-premise wireless paging system that uses weak radio waves, which are allowed to be used freely under the Radio Law, to provide a wide on-premises service area. The purpose is to provide a wireless paging system.

[Means for solving problems]

The in-premises radio paging system according to the present invention includes a plurality of devices in which a radio transmitter that sends out a radio paging signal and a radio paging control device are integrated, and a plurality of devices are arranged in a distributed manner, and the devices are connected in a broadcast communication format. and transmits radio paging and control information from the center's radio paging control device connected to the central PBX to other radio paging control devices in a broadcast communication format via the communication cable, Each radio paging control device that receives this radio paging control information refers to information given in advance about the positional relationship in which each device is installed, and controls the sending timing of the radio paging signal. be.

[Effect]

In the premises radio paging system of the present invention, each radio paging control device controls the sending timing of the radio paging signal by referring to information given in advance about the positional relationship in which each radio paging control device is installed. According to the Radio Law, a radio paging system using a single radio transmitter that uses weak radio waves makes it possible to provide a radio paging service without any interference such as interference, even in large premises where the premises service area cannot be covered.

〔Example〕

FIG. 1 is a block diagram showing the configuration of a local wireless paging system which is an embodiment of the present invention. In the figure, 1 is PBX, 3-1, 3-2.3-3.

3-4 is an antenna, 4 is a special trunk circuit device, 5-1
．． 5-2 are private telephones TA, TB, 6-1.6-2 respectively.
are the radio calling mobile terminals PX, Py, 7-1, respectively.
7-2, 7-3, 7-4, 7-5
, 7-6.7-7 is a radio call control device, 8-1
．． 8-2, 8-3, 8-4, 8-5 are communication cables, 9-1, 9-2, 9-3, 9-4 are repeaters, 10-1.10-2.10-3.10 -4 is a wireless transmitter.

FIG. 2 is a diagram showing a transmission sequence of a radio paging signal in the premises radio paging system of FIG. 1, and FIG. 3 is a diagram showing radio paging control information transmitted onto the communication cable in the premises radio paging system of FIG. 1. It is a figure which shows a frame.

Next, the operation of the local wireless paging system, which is an embodiment of the present invention shown in FIG. 1, will be described. First, when a user in the premises makes a wireless call, when he dials a special number from his own telephone T5-1, the special trunk circuit device 4 of the PBXI is captured. This special trunk circuit device 4 is a wireless paging control device 7-1 installed at the center.
Information such as the called wireless terminal number 2 dialed from the local telephone TA5-1 and the calling telephone number is received here and temporarily stored. When the reception of the predetermined dial information is completed, the center's wireless paging control device 7-
1 activates the wireless transmitter 10-1 still coupled to the device, and transmits the already received and stored called wireless terminal number and calling telephone number in the form of information as illustrated in FIG. After adjusting the antenna 3 and applying appropriate modulation to the radio carrier wave,
-1 transmits radio waves. At the same time, the wireless paging control device 7-1 of the center connects each communication cable 8-1 to 8-5.
via other plurality of radio call control devices 7-2 to 7-
7, and radio call control information is transmitted all at once in broadcast communication format. Note that each repeater 9-
1 to 9-4 are used when extending each communication cable 8-1 to 8-4, and are not directly related to the essence of the present invention. The radio call control information is transmitted in an information frame as shown in FIG. That is, D.A.
indicates the destination address, SA indicates the source station address STN, and each radio call control device 7-1 to 7
-7 each has a unique station address STN of 5T.
Uniquely added from N-1 to 5TN=7,
In the example shown in FIG. 1, 5TN=1. C indicates a control representing the meaning of the information frame of radio call control information, and Fe2 indicates a redundant bit for detecting errors in the information frame. In normal operation, each radio paging control device 7-1 to 7-7 connects to each communication cable 8.
Among the information frames flowing on -1 to 8-5, only valid information frames whose destination address DA matches the station address STN uniquely assigned to each station are taken in. When the code is, for example, Al11, a broadcasting function can be provided to receive the information frame from all the radio call control devices 7-1 to 7-7. The operations on each of the communication cables 8-1 to 8-5 as described above are known as a bus-type local area network (LAN) standardized by the IEEE802.3 LAN standardization committee in the United States, for example. , a detailed explanation will be omitted here.

In the above-mentioned premises radio paging system, since the whereabouts of the called radio end non-subscriber within the premises is generally unknown, information as shown in FIG. Each radio paging controller 7-3.7-4°7-7 that has received the frame activates each radio transmitter lO-2.10-3.10-4 coupled to it, and
The wireless terminal paging signal field portion of the information frame shown in the figure is extracted, modulated onto a wireless carrier wave using an appropriate method, and transmitted as weak radio waves through each of the antennas 3-1 to 3-4. Here, when the plurality of radio call control devices 7-3, 7-4, and 7-7 transmit radio waves at the same time, although the radio waves are weak, the mutual positional relationship l of these radio transmitters is This causes interference in the called radio-calling mobile terminal, and a problem arises in that normal reception of radio signals is hindered.

In order to avoid such problems, in the premises radio paging system according to the present invention, in order to prevent the radio waves transmitted from the radio transmitters located close to each other from overlapping in time, as shown in FIG. The transmission time TP of radio waves is shifted as shown in FIG. In the example shown in Figure 2, each group of 5TN=1.4 and each 5T
A case is shown in which radio paging signals are transmitted in two groups of N=3.7. in this way,
The grouping that requires shifting the transmission timing can be optimally selected in advance by the arrangement of each wireless transmitter that will not cause interference even if simultaneous transmission is performed.

Further, the delay time TD by which the transmission timing of the wireless transmission radio waves should be shifted is generally set as TD=N×TP. Here, N is 0, 1, 2. ...... integer, T
P indicates the paging signal transmission time, which is the maximum time during which radio waves are transmitted until the paging of one radio paging mobile terminal ends. If the radio transmitters are relatively sparsely arranged, it is sufficient to divide them into two groups: N-0 (no delay in radio wave transmission) and N=1 (delay by TP).

Further, the setting of the delay time TD is determined based on the radio paging control information received in broadcast communication format via the communication cable and the arrangement position information given in advance for each of the radio paging control devices 7-1 to 7-. 7tC, and can be easily implemented by using a microprocessor or the like.

〔Effect of the invention〕

As explained above, the present invention provides a premises radio paging system in which a plurality of radio transmitters are distributed in a premises,
In addition, since the configuration is configured to control the radio transmission timing from these radio transmitters by temporally shifting, it is possible to prevent interference such as interference even in large campuses where a single radio transmitter cannot secure a sufficient campus service area. In addition, the transmission power per wireless transmitter can be reduced, which eliminates the overload that is unique to wireless communication systems.
This has excellent effects such as avoiding the problem of reach.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a local wireless paging system which is an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a local wireless paging system. FIG. 3 is a diagram showing a transmission sequence of a radio paging signal in the premises radio paging system of FIG. 4 is a block diagram showing the configuration of a conventional in-premises wireless paging system, and FIG. 5 shows #i
FIG. 3 is a diagram illustrating an example of a control information format for selectively calling a line-calling mobile terminal; In the figure, 1...PBX, 2...Wireless paging center device, 3.3-1 to 3-4...Antenna, 4...
Special trunk circuit device, 5-1.5-2...Public telephone T, TB, 6-1.6-2...Radio paging mobile terminal P P 7-1 to 7-7...Radio Call control X"y' device, 8-1 to 8-5...communication cable, 9-1 to 9
-4... Repeater, 10-1 to 10-4... Wireless transmitter. In each figure, the same reference numerals indicate the same or complementary parts.

Claims (1)

[Claims] In a campus wireless paging system that uses weak radio waves,
A plurality of devices that are integrated with a radio transmitter that modulates and transmits a radio paging signal and a radio paging control device that controls this radio transmitter are distributed in a campus, and each of the radio paging control devices is The radio paging control information from one specific radio paging control device installed at the center is sent out all at once via the communication cable in a broadcast communication format, and is then wirelessly transmitted. After receiving the radio paging control information, all the other radio paging control devices having the radio paging control devices, after receiving the radio paging control information, calculate N× T_P(N is 0, 1,
2. T_P is an integer of . A premises wireless paging system characterized by transmitting.