KR100224561B1 - Apparatus for priority call in a satellite communication system, and method thereof - Google Patents

Abstract

The present invention provides a priority call apparatus and method in a satellite communication system that allows a call to be restricted or perform a priority call based on a subscriber's grade when a call occurs in an overload or emergency situation of a satellite communication system. A satellite communication system comprising: a plurality of base stations each coupled with a plurality of subscribers, and a central control station coupled with an operator and for managing and controlling the base stations; The base station includes a system state information storing means for storing a system state of a normal call mode or a priority call mode, subscriber grade information storing means for storing priority grades assigned to each subscriber line, and the system state information storing means. And a control means for selectively controlling a call based on the priority level when there is a call request from any subscriber in the state of setting the priority call mode.

Description

Priority Calling Device and Method in Satellite Communication System

The present invention relates to a communication system using satellite, and in particular, in a satellite communication system that allows a call to be restricted or to perform a priority call based on the subscriber level when a call occurs in an overload or emergency situation of the system. A priority call apparatus and method are provided.

Recently, with the rapid development of communication technology, satellite communication, which enables subscribers who are located at remote sites to make calls through satellites, has become increasingly common. Since such satellite communication does not require a separate signal line for a call, It is mainly used as a long distance communication between countries or as a communication method in a mountainous country such as Korea.

In the above-mentioned satellite communication, a PAMA (Pre-Assignment Multiple Access) method for allocating communication channels for each subscriber according to the channel assignment method and a DAMA (Demand Assignment Multiple Access) method for allocating communication channels according to a subscriber's request There are two methods. In general, in the satellite communication system for communication between subscribers, many DAMA methods are adopted in consideration of the cost and the effectiveness of the communication channel.

1 is a block diagram showing the overall system configuration of a general satellite communication system according to the DAMA method.

In Figure 1, reference numeral 1 is a satellite having a plurality of communication channels, 2 is a central control station for controlling the entire satellite communication system, 3 (3A, 3B) is a data terminal and facsimile, such as an exchange, a telephone, a computer, etc. A base station having an interface function for a terminal and providing a call function between the various terminals through data transmission and reception with the central control station 2.

In FIG. 1, reference numeral S denotes a service channel for transmitting and receiving control data, and T denotes a traffic channel for transmitting and receiving data or voice.

In the above-described configuration, the central control station 2 transmits a control message through a service channel in a normal state and then, based on a response message sent from the base station 3, that is, communication It performs a polling function to check the available capacity or the utilization status of the communication channel. When there is a call request from a specific base station, for example, the base station 3A to the terminal of the base station 3B, it is determined whether the corresponding base station 3B is in a state in which communication is possible based on the information obtained in the polling process. In the case of the communicable state, the available traffic channel T of the satellite is allocated to both base stations 3A and 3B so that both base stations 3A and 3B can directly communicate with each other.

Subsequently, when the communication between the base stations 3A and 3B is terminated and the communication termination signal is applied through the service channel S from the base station 3A, which has been requested for communication, the central control station 2 is applied to both base stations. By executing the communication termination process, the traffic channel T which has been provided to both base stations 3A and 3B is released.

2 is a block diagram showing the configuration of the central control station 2 described above.

In FIG. 2, reference numeral 21 is an antenna for transmitting / receiving an satellite 1, an uplink signal, and a downlink signal, and 22 is an antenna 21 through the antenna 21 using a polarization property of frequency. Orthogonal Mode Transducer (OMT) for separating and transmitting and receiving signals, 23 is a low-noise amplifier for low-noise amplifying 12.25 to 12.75 GkHz downlink frequency signal input through the orthogonal mode converter (22) Low Noise Amplifier (LNA), 24 is a frequency down converter (DC) for converting a frequency signal applied through the low noise amplifier 23 into an intermediate frequency signal IF of 70 MHz, for example.

In addition, reference numeral 25 separates and outputs the intermediate frequency signal IF applied from the frequency down converter 24 into a plurality of intermediate frequency signals, and also describes a Single Channel Per Carrier (SCP) channel unit to be described later. An intermediate frequency combiner / distributor (IF C / D) for combining and outputting an intermediate frequency signal applied from the SCU: 26, and 26 is an intermediate applied from the intermediate frequency combiner / distributor 25. It is a SCPC channel unit for demodulating, decoding, and outputting a frequency signal, and encoding and modulating and outputting a message output from the network controller 40 to be described later.

Here, the intermediate frequency combination / distributor 25 is employed for system scalability when using a plurality of SCPC channel units.

Further, reference numeral 27 denotes a frequency up-converter for converting an IF signal of 70 MHz applied from the IF combination / distributor 25 into an microwave of 14.0 to 14.5 GHz to generate an uplink frequency signal. And 28 are high power amplifiers (HPAs) for amplifying uplink frequency signals output from the frequency up-converter 27.

Reference numeral 40 denotes a state of each base station 3 based on a response message transmitted from the base station after transmitting a control message to each base station 3 through an arbitrary SCPC channel unit 26 _{1 to} 26 _N. Perform a polling function that checks whether a call is received from a specific base station, and determines if the other base station is in a communication state based on the information obtained in the polling process, and uses a satellite in a communication state. It is a network control unit that performs system control, such as by assigning possible traffic channels (T) and modems to both base stations to directly communicate with each other.

In addition, reference numeral 50 denotes a network management system for managing the overall network of the satellite communication system by the system administrator to manage the network control unit 40, the network management system 50 is coupled to the operator terminal 51 The operator terminal 51 operates according to a command input from an administrator who manages system operation and displays the state of the system through a predetermined display device.

3 shows the configuration of the base station 3 in FIG.

In general, the base station 3 has a configuration similar to that of the above-described central control station 2 as shown in FIG. 3, and since most of the configuration performs the same function as that of the central control station 2, it performs the same function. The detailed description is abbreviate | omitted about the structure to make.

In FIG. 3, reference numeral 70 denotes a base station control unit which performs overall control of the base station. The base station control unit 70 is an arbitrary SCPC channel unit 66 _{1 to} 66 _N according to a control signal received from the central station 2. Or by allocating a communication channel so as to perform communication between subscribers, and control to output base station information such as a call setup state and a channel use state of the subscriber coupled to the base station 3 to the central control station 2. do.

Next, the operation of the satellite communication system having the above configuration will be described.

In the normal state, the network controller 40 of FIG. 2 periodically performs a polling operation to check the state of each base station and allocate an arbitrary communication channel based on the call request message required by the base station 3.

That is, the network controller 40 generates a message of the TDM stream from the packet data for checking the state of each base station, and then designates an arbitrary SCPC channel unit 26 to output the message.

The SCPC channel unit 26 converts the message into an intermediate frequency signal of 70 MHz by encoding and modulating the message and outputs the intermediate frequency signal. The intermediate frequency signal is combined by frequency in the IF combination / distributor 25, The frequency increase converter 27 converts the uplink frequency signal of, for example, 14.5 GHz. The uplink frequency signal is output through the high power amplifier 28, the quadrature mode converter 22, and the antenna 21, and then transmitted to each base station 3 through the satellite 1 in FIG.

Then, when the base station control unit 70 of the base station 3 receives the downlink frequency signal of the TDM stream through the satellite 1, it extracts packet information from the frequency signal to the subscriber to any communication channel or SCPC channel. By allocating units, the controller can control the mutual communication or generate a response message of the S-ALOHA packet for the polling message and send it to the central control station 2.

On the other hand, the response message received from the base station 3 through the satellite 1 to the antenna 21, that is, the downlink frequency signal of 12.25GHz is frequency down through the orthogonal mode converter 22 and the low noise amplifier 23. It is applied to the converter 24 and converted into an intermediate frequency signal of 70 MHz, and then applied to an arbitrary SCPC channel unit 26 through the IF combination / distributor 25, demodulated and decoded, and then to the network controller 40. To be authorized.

In addition, the network controller 40 extracts packet information from the received message to generate an S-ALOHA packet, and then updates and registers a predetermined base station information storage unit based on this to hold state information for all base stations.

In addition, the network controller 40 outputs the base station status information received from each base station 3 to the network management system 50, and the network management system 50 displays it through a predetermined display device.

In addition, the above-described polling operation is continuously performed for each base station.

On the other hand, if there is a call request from another base station to another base station during the above-described polling operation, the network controller 40 reads the state information of the base station called from the predetermined base station information storage unit, and the base station is presently present. It is determined whether communication is possible. At this time, when it is determined that the communication is possible, the communication channel currently available is examined and the channel is allocated to the calling base station.

When the communication channel is allocated, the base station 3 assigns itself an SCPC channel unit 66 _{1 to} 66 _N to control mutual communication between subscribers.

As described above, when there is a call request from any subscriber, the base station control unit 70 generates a series of S-ALOHA packets and sends them to the central control station 2, and the central control station 2 is currently available for communication. The channel will be searched and assigned.

By the way, in general, the communication channel provided by the satellite 1 is limited, and the number of subscribers who want to use this communication channel is relatively large.

Therefore, if a plurality of subscribers are talking or attempting to talk at the same time, the system may be congested and cause an overload of the system, causing a malfunction of the system. In addition, it is possible to predict the possibility that a serious policy situation may occur when important policy makers fail to communicate critical information in the event of a war or a similar emergency.

Accordingly, the present invention has been made in view of the above circumstances, and when a call occurs in an emergency situation such as an overload or an emergency system, it limits the call request of the general subscriber based on the subscriber rating and It is an object of the present invention to provide a priority call apparatus and a method in a satellite communication system capable of providing a priority call function that firstly receives a call request.

1 is an overall system configuration for explaining the outline of a general satellite communication system.

FIG. 2 is a block diagram showing the configuration of the central control station 2 in FIG.

3 is a block diagram showing the configuration of a base station 3 in FIG.

Figure 4 is a functional block diagram showing the configuration of a priority call (Priority Call) device in a satellite communication system according to an embodiment of the present invention.

FIG. 5 is an operational flowchart for explaining the operation of the apparatus of FIG. 4. FIG.

* Brief description of the main parts of the drawing

1: satellite 2: central control station

3A, 3B: base station 21, 61: antenna

22, 62: orthogonal mode converter 23, 63: low noise amplifier

24, 64: Frequency down converter 25, 65: Intermediate frequency combination / distribution

26, 66: SCPC channel unit 27, 67: frequency converter

28, 68: high power amplifier 40: network control unit

50: network management system 51: operator terminal

70, 80: base station control unit 81: system status information storage unit

82: subscriber grade information storage

In the satellite communication system according to the first aspect of the present invention for realizing the above object, the preferred call method includes a plurality of base stations each coupled with a plurality of subscribers, and a central control station coupled with an operator and managing and controlling the base stations. A satellite communication system; The central control station includes a call priority class registration step of setting and setting a call priority level for each subscriber line when the system is activated, and a call priority class broadcasting step of broadcasting this data to the base station when the call priority level is registered for each subscriber line. The base station is configured to store the call priority level data when the call priority level data is received from the central control station in a predetermined memory, and when an emergency state message of the system is received from the central control station. The priority call mode setting step of updating and setting the operation mode to the priority call mode based on the message, and upon request from any subscriber in the priority call mode setting step, based on the call priority level data of the memory. It comprises a selection call processing step of controlling the call request processing of the call subscriber It characterized.

In addition, in the satellite communication system according to the second aspect of the present invention, the preferred call apparatus includes a plurality of base stations, each coupled with a plurality of subscribers, and a central control station coupled with an operator and managing and controlling the base stations. In; The base station includes a system state information storing means for storing a system state of a normal call mode or a priority call mode, subscriber grade information storing means for storing priority grades assigned to each subscriber line, and the system state information storing means. And a control means for selectively controlling the call processing based on the priority level when there is a call request from any subscriber in this priority call mode.

That is, according to the above configuration, it is possible to selectively control the call request based on the call priority level for each subscriber line in the overloaded state of the system.

On the other hand, Figure 4 is a block diagram showing the configuration of the preferred call device in the satellite communication system according to an embodiment of the present invention, the embodiment of the present invention with reference to the same diagram in more detail.

In FIG. 4, reference numeral 81 denotes a system state information storage unit for storing system concurrent subscriber status information indicating whether the number of subscribers currently using the system is normal or exceeded the expected number of concurrent subscribers in the system design with a predetermined flag. The system state information storage unit 81 updates and registers the flag state from the normal mode to the priority call mode in accordance with a predetermined control signal of the base station controller 80 to be described later.

Also, reference numeral 82 is a subscriber grade information storage unit for storing predetermined call grade information for a plurality of subscribers. The subscriber grade is similar to the system status grade for each subscriber line when the system is started. It is granted and can be changed by the operator during operation.

The subscriber class indicates the possibility that a call can be set when a call of any subscriber is converted into a grade. When a call is requested by a subscriber, the base station controller 80 to be described later is based on the subscriber grade of the subscriber. The state data of the system state grade information storage unit 81 is compared and a series of call processing is performed based on the result.

That is, if the current system status class is the priority call mode and the subscribers who call the call are the same priority call mode, the request of the subscriber is accepted and the call processing is performed afterwards. The base station controller 80, which will be described later, sends a congestion sound to the subscriber without performing the call processing operation of the subscriber.

In addition, reference numeral 80, for example, as described with reference to FIG. 3, when a subscriber requests, it is possible to perform communication between subscribers by assigning an arbitrary SCPC channel unit (66 ₁ ~ 66 _N ) or communication channel, It outputs the base station information such as the call setup state, channel usage state, etc. of the subscriber coupled to the base station 3 to the central control station 2, and the system status information and the subscriber class information received from the central control station 2; By changing the data of the system state information storage unit 81 and the subscription level information storage unit 82 on the basis of the above, it is possible to control a series of priority call functions.

Next, the operation of the device having the above configuration will be described using the operation flowchart of FIG. 5.

First, the central control station 2 periodically performs a polling operation as described with reference to FIGS. 2 and 3 to obtain status information of each base station including the number of lines currently in use received from each base station 3. Will have. In addition, based on the current athletes, the operator is displayed using a predetermined output means so that the operator can easily identify the operator, and the operator monitors the display device.

Thereafter, when the operator monitors the display device and recognizes a predetermined indication due to exceeding the number of simultaneous subscribers at some point, for example, the operator may change and register the operation state in the priority call mode of the system. When the operation state is changed and set through the operator terminal 51, the network controller 40 generates a series of TDM stream messages based on the state information of the system and transmits them to the base station.

Subsequently, when the base station control unit 80 of the device station 3 receives an emergency status message for the system from the central control station 2 (step ST51), the base station control unit 80 of the system state information storage unit 81 The flag state is updated and registered as an emergency state (step ST52).

Subsequently, when there is a call request from any subscriber in the state in which the flag state of the system state information storage unit 81 is registered as an emergency state (step ST53), the base station controller 80 determines the subscriber state. The data of the rating information storage unit 82 is read to retrieve the call priority level of the call subscriber (step ST54).

Subsequently, if the call priority level of the call subscriber is the priority call level (ST55), the base station controller 80 generates an S-ALOHA packet for the call subscriber's call request and sends it to the central control station 2 for normal call request. Processing is performed (ST56 step).

On the other hand, the base station controller 80 retrieves the call request by sending a congestion sound to the caller line if the call priority level of the current call subscriber is not the priority call level as a result of searching the subscriber class information storage unit 82 in step ST55. It will be ignored (ST57 step).

That is, according to the embodiment, as described above, when the call priority class is registered for each subscriber line when the system is activated, when there is a call request in the system overload condition, the call request is selected and controlled based on the call priority class of the call subscriber. Done.

In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the technical gist of the present invention.

As described above, according to the present invention, when a call occurs in an overload or emergency situation of the system, the priority call apparatus in the satellite communication system that allows to limit the call or to perform a priority call based on the subscriber's rating; The method can be realized.

Claims (3)

A satellite communication system in which a plurality of base stations, each coupled with a plurality of subscribers, is combined with a central control station via satellite to perform communication between subscribers; The central control station, Call priority class registration step of setting and registering the call priority level for each subscriber line when the system is activated, When the call priority level is registered for each subscriber line, the call priority level broadcasting step of broadcasting this data to the base station is configured. The base station, A call priority class storing step of storing the call priority class data in the predetermined memory when the call priority class data is received from the central control station; A priority call mode setting step of updating and setting an operation mode to a priority call mode based on this message when an emergency message of the system is received from the central control station; And a selective call processing step of controlling a call request process of a call subscriber based on call priority level data of the memory when there is a call request from any subscriber in the priority call mode setting step. Preferred call method in communication system. A satellite communication system comprising a plurality of base stations each coupled with a plurality of subscribers, and a central control station coupled with an operator and managing and controlling the base stations; The base station, System state information storing means for storing a system state in a normal call mode or a priority call mode; Subscriber grade information storage means for storing the priority grade given to each subscriber line; And a control means for selectively controlling call processing based on the priority level when a call request is received from any subscriber in the state where the system state information storing means is set in the priority call mode. Preferred call device in a communication system. The method of claim 2, And the control means receives the priority call mode or subscriber priority class from the central control station and stores the priority call mode or subscriber priority class in the corresponding memory, respectively.