JP2953738B2 - Demand assignment method - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) In the present invention, a plurality of slave stations communicate via a line, such as satellite communication and terrestrial microwave communication, and a central control station The present invention relates to a demand assignment system for allocating a free line according to a call sent from a calling station.

(Prior art) As a conventional example of this demand assignment method,
A system disclosed in Japanese Patent Application Laid-Open No. 62-1331 is known.
In this conventional demand assignment method, a call that has occurred is accepted and held even when all lines are blocked, and the line is assigned to a call that is on hold as soon as one of the lines becomes free.

(Problems to be Solved by the Invention) However, in such a method, when the hold time is long, a case occurs in which the caller forgets that the call is on hold and leaves the terminal. In this case, the line is allocated. However, when there is no caller, that is, when viewed from the called party side, an infinite telephone call is made, and useless line allocation is performed.

Further, even when there are a plurality of calls in a hold state, a line that is generated earlier in time is preferentially assigned to a line, so that a problem with a higher urgency is postponed.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional demand assignment system as described above, and a first object of the present invention is to provide a demand assignment system that does not cause useless line assignment. A second object of the present invention is to provide a demand assignment system that can assign a line to a call having a high urgency first.

[Constitution of the Invention] (Means for Solving the Problems) In the present invention, first, a plurality of slave stations communicate via a line, and a central control station responds to a call sent from a calling station. In the demand assignment method for allocating a free line, a call generated while all the lines are blocked is accepted and held, and when one of the lines becomes free, the necessity / unnecessity of the line allocation is confirmed for the held call. To assign lines only to calls that need to be assigned.

Second, in the present invention, in a demand assignment system in which a plurality of slave stations communicate via a line and a central control station allocates an empty line according to a call sent from a calling station, all the lines are used. Even in the closed upper body, the number of occurrences is accepted and held, and when one of the lines becomes free, the line is assigned based on the priority of the call.

(Operation) According to the configuration of the first aspect of the present invention, if one of the lines becomes free, it is determined whether or not a line is to be held and whether or not the line is allocated is determined, and the line is allocated only to the call that needs to be allocated. The line is not allocated to a call in which the caller has left the terminal during the call, and the line is efficiently allocated.

Further, according to the configuration of the second invention, when one of the lines becomes free, the line is allocated from a call having a predetermined higher priority order among the held calls, and a call having a high urgency occurs. Since the time is later, the problem that the line assignment is delayed can be eliminated.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of a satellite communication system employing a demand assignment system according to one embodiment of the present invention. In the figure, A to Z indicate ground stations, and 1 indicates a central control station. The ground stations A to Z and the central control station 1 are connected by a line using a satellite 2. Ground station A
ＺZ have the same configuration, the transmission / reception unit 201, the line control unit 2
02, including a communication control unit 203 and a ground station control unit 204. The ground stations A to Z are connected to the terminal 4 via the ground exchange 3. The central control station 1 has the same functions as the ground stations A to Z,
The terminal is connected to a terminal via a ground exchange (not shown). In addition, a line is allocated to the ground stations A to Z. The central control station 1 includes a transmitting / receiving unit 101, a line control unit 102, a central control unit.
104, a communication control unit 103 is provided. The transmission / reception units 101 and 201 transmit / receive radio waves to / from the satellite 2 via an antenna. The line controllers 102 and 202 multiplex and demultiplex the terminal signals, and insert and extract signals into and from predetermined lines designated by the centralized controller 104 or the ground station controller 204. Communication control unit 104,
Reference numeral 204 denotes a signal sent from the terrestrial exchange 3 to the line control units 102 and 2
02 or the central control unit 104 (the ground station control unit 204). The central control unit 104 and the ground station control unit 204 receive call control signals from the line control units 102 and 202 and the communication control units 103 and 203. In this communication system, a line through which a call control signal is transmitted and received is reserved in advance.

Although it has been described that the central control station 1 allocates lines, the central control unit 104 actually has the configuration shown in FIG. 3, and this performs line allocation. That is, the central control device 7, the storage unit 5, and the input / output device 6 are connected via the bus 8. The central control unit 7 has a computer configuration and controls line allocation based on programs and data in a main memory of the central control unit 7. The input / output device 6 includes, for example, a keyboard and a display, and is used for inputting data indicating the priority order of calls. The storage unit 5 is a memory used by the central control device 7, and may be a part of the main memory. The storage unit 5 has a line idle / busy state table 51,
A waiting queue table 52 and a call priority order table 53 are provided. In the line idle / busy table 51, “1” indicates that the line is closed, and “0” indicates that the line is empty, and line numbers 1 and 2 indicate that all lines are closed. The waiting queue table 52 stores the terminal identification information (displayed by the alphabet of the ground station and the three-digit number) of the call waiting for an available line. The call priority order table 53 stores the terminal identification information of the call for which the priority order is determined, and the calls of the terminal identification information not present here are arranged in the waiting queue table 52 in the order of occurrence as in the related art. The terminal with the priority is, for example, a terminal for disaster communication. Also, call priority order table
53 "Broadcast No. 2 and emergency No. 1" indicates that the priority order differs depending on the content of the communication, and the order based on this content is lower than that based on the terminal identification information.

The central controller 7 controls the line allocation based on the program of the flowchart shown in FIG. 4 stored in the main memory. For example, when the terminal 4 shown in FIG. 2 transmits a predetermined dial signal, the signal reaches the ground stations A to Z via the ground exchange 3, and is given from the communication control unit 203 to the ground station control unit 204. Therefore, the ground station control unit 204 determines the identification information and the communication type (broadcast etc.) of the calling station terminal and the called station terminal.
Is sent to the line control unit 202, the signal reaches the central control station 1 via the satellite 2, and is received by the central control unit 104. That is, it is received by the central control device 7 in FIG. Therefore, the central control unit 7, which has been monitoring the line request in FIG. 4, branches to YES in step 401 and refers to the line idle / busy table 51 to check whether there is an empty line (402). If there is a free line, a line assignment signal indicating the assignment to the line is given to the corresponding calling / called ground station based on the identification information (403). The ground station control station 204 of the ground station includes a line control unit 202, a communication control unit 203
Is controlled to connect the terrestrial exchanges 3 to each other, thereby enabling the terrestrial exchange 3 to call the called terminal 4, start and end the call. At the end of the call, the ground station control unit 204 notifies the central control unit 104 that the corresponding line is free.

On the other hand, when it is detected in step 402 that there is no free space, a link busy signal indicating this is given to the ground stations A to Z and the ground exchange 3 via the line of the call control signal, and the ground exchange 3 makes a call. The terminal is put on hold (for example, an audio transformer is controlled to listen to music or an announcement indicating that the terminal is on hold) (404). The central control unit 7 makes a call priority order table 53 based on the terminal identification information and the communication type of the held call.
Is searched to see if it is a priority call (405). Here, if the call is a priority call, the waiting queue is arranged at a corresponding position in the waiting queue table 52 (406). If the call is not a priority call, the waiting queue is arranged at the end of the waiting queue (407). Then, it waits for the occurrence of an idle line (408). When an idle line is generated, a confirmation instruction is given to the corresponding ground station to send a message or signal for confirming the line request to the called terminal 4 (409). This signal is given in the reverse route to the line request. Then, the ground station causes the ground exchange 3 to which the calling terminal 4 belongs to send a confirmation message to the calling terminal, ask for a response from the calling terminal (for example, the same dial input as when requesting a line, etc.), and The presence or absence is checked (410). Here, when there is a response from the calling terminal, the ground exchange 3 notifies the ground station of the response. The ground station receives this and notifies the central control station 1 of a response. Therefore, the central control unit 7 sends a notification of the assignment of the line to the corresponding ground station, deletes the corresponding waiting queue in the waiting queue table 52, and raises the order of the other waiting queues by one (411). . On the other hand, if there is no response, the corresponding waiting queue is reduced in the waiting queue table 52, and the ranks of the other waiting queues are raised one by one (412), and the process ends.

The terminal 4 is provided with a communication type designation key.
Called terminal identification information and communication type information are transmitted by dial input and operation of the designation key. The calling station terminal information is sent from the ground exchange 3.

FIG. 1 illustrates a case where a call having no priority and a call having a priority occur from the ground stations A and B in the satellite communication system having such a configuration. At time t ₁ , a line request signal is sent from the ground station A to the central control station 1. This called station is assumed to be Z. However, since there is no available line, a link busy signal is sent from the central control station 1 to the ground station A, and the calling terminal is put on hold. Next, the line request signal having a type of emergency communications from the ground station B as the called terrestrial stations Y at time t ₂ are output. Also at this time, since there is no free line, a link busy signal is returned to the ground station B, and the signal is put on hold. This call has a higher priority than the call generated at time t _1, are arranged above as waiting queues. Times of Day
Since no free line occurs turned t _3, the centralized control station 1 sends a signal asking for confirmation to the ground station B (higher priority). Line Here, the central controller 7 enters the time-over count of [Delta] T, for a response at time t ₄ before the expiration of [Delta] T, the centralized control station 1 to the calling ground station B and the called ground station Y Assign.

On the other hand, the signal requesting confirmation to the ground station A for further idle line occurs at time t ₅ is output, no response from the calling terminal, due to a time over the [Delta] T, indicating that the line has been assigned .

[Effects of the Invention] As described above, since the line is allocated after confirming from the hold state, there is no wasteful allocation and the efficiency is high.
In addition, since the assignment is performed based on the priority order, an appropriate line can be assigned without delaying the assignment of the line for the emergency call.

[Brief description of the drawings]

FIG. 1 is a time chart showing a channel assignment operation according to the present invention, FIG. 2 is a block diagram of a satellite communication system adopting the present invention, FIG. 3 is a block diagram of a main part of FIG. 2, and FIG. Is a flow chart showing a line assignment operation according to FIG. 1 ...... central control station, 2 ...... satellite 3 _A to 3 _Z ...... terrestrial exchange 6 ...... output device 7 ...... central controller 101, 201 ...... transceiver 102, 202 ...... line control unit 103 and 203 ...... communication control unit 104 ...... Central control unit 204 ...... Ground station control units A to Z ...... Ground station

Claims (2)

(57) [Claims] In a demand assignment system in which a plurality of slave stations communicate via a line and a central control station allocates an empty line in response to a call sent from a calling station, all lines are blocked. A call generated in this state is accepted and put on hold, and when one of the lines becomes free, it is checked whether or not the call on hold is necessary / unnecessary to assign a line, and the line is assigned only to the call that needs to be assigned. Characteristic demand assignment method. 2. A demand assignment system in which a plurality of slave stations communicate via a line and a central control station allocates an idle line in response to a call sent from a calling station, and all lines are blocked. A demand assignment method characterized in that a generated call is received and held even in a state, and when one of the lines becomes free, a line is allocated based on the priority of the call.