KR100264044B1 - Emthod of connecting pstn call in satellite communication - Google Patents

Abstract

PURPOSE: A method for setting up a general telephone network call in a satellite communication system is provided to make a call setting up easy and to increase a complete rate of telephone call by assigning a priority for a general telephone network call connection and trying the call connection according to the priority in the case of call connection failure. CONSTITUTION: In step ST1, a processor reads out particular packet data from a dual port RAM, and updates and registers a base station information storing part to obtain state information for each base station. If a calling request from one base station connected to PSTN to other base station is present(step ST2), the processor reads out state information about the other base station from the base station information storing part and determine whether a communication is possible or not(step ST3). If the communication is possible(step ST4), an available communication channel is searched from a channel information storing part(step ST6). The available communication channel is assigned to the base stations and the base stations can communicate with each other(step ST7). If the communication is not possible(step ST4), the processor performs the call connection to another base station based on a call connection priority information stored in a call connection priority information storing part(step ST5). If the communication is ended(step ST8), a message indicative of the call completion is sent to a central control station and the channel is set to an available state.

Description

General telephone network call setup method in satellite communication system

The present invention relates to a communication system using satellites, and in particular, the central control station that manages a plurality of base stations grasps and stores and manages a general telephone network communication connection state of each base station, and requests a call connection from a general telephone network subscriber through an arbitrary base station. On the method of establishing a general telephone network call in a satellite communication system that can increase the call success rate by making a call connection through a designated base station in the next order in case of failure by executing a call connection based on the identified communication connection state. will be.

Satellite communication using satellites generally means that voice or data communication is performed between subscribers at remote sites through a satellite stationed at an altitude of 36000 km. FIG. 1 shows a communication channel according to a subscriber's request. This shows the overall system configuration of the Demand Assignment Multiple Access (DAMA) satellite communication system.

In Fig. 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, and 3 (3A, 3B) is an exchanger (11A, 11B) or a telephone (12A, 12B). Communication function between the various terminals through data transmission and reception with the central control station 2 as well as an interface function for terminals such as data terminals 13A and 13B and facsimile 14A and 14B, such as a computer. The base station that provides.

In addition, 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.

That is, in the satellite communication system having the above-described configuration, the central control station 2 normally transmits a control message through the service channel, and then, based on the response message transmitted from the base station 3, each base station 3 It performs a polling function to check the state of the communication capacity or the availability of the communication channel.

When there is a call request from a subscriber, for example, a base station 3 to a terminal under the control of the base station 3B, it is determined whether the base station 3B is in a state capable of communication 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 receives By executing the communication termination process, the traffic channel T which has been provided to both base stations 3A and 3B is released.

On the other hand, in the above-described satellite communication system, when a PSTN subscriber requests a call connection through an exchange 11B connected to a base station 3 controlled by a central control station 2, the call connection request is It is delivered to the base station 3B connected to the exchange 11B. Therefore, the base station 3B that receives the call connection request from the PSTN subscriber checks whether the call connection target belongs to the subscriber network under the control of the base station 3B itself, and if it belongs to its own subscriber network, " Call connection is made through "Local Call" function.

However, if the call connection target requested by the PSTN subscriber belongs to another base station 3A outside the jurisdiction subscriber network, the base station 3B requests a call to the central control station 2 via the satellite 1. (Calling)

Subsequently, the central control station 2 determines whether the base station 3A, which is in charge of the call connection target connected to the PSTN, is in a communicable state, based on the information obtained during the polling process. If the link is disconnected between the base station 3A that manages the call connection target and the terminal to which the call is connected, the central control station 2 requests the call connection. Through the corresponding base station 3B, a busy tone signal indicating that a call cannot be made to a subscriber station requesting a call connection is transmitted.

Therefore, the PSTN subscriber requesting a call connection hangs up his terminal and requests a call connection again, and the central control station 2 receiving the call request through the base station 3B again receives the call. A call is set up using another base station 3n, which is connected to the telephone network PSTN, as the destination terminal station.

Therefore, in the PSTN subscriber, when a communication is lost due to a request for a call and a link is disconnected, or a busy tone signal is received, the call connection must be executed again each time.

Accordingly, the present invention has been made in view of the above circumstances, and the central control station having jurisdiction of a plurality of base stations designates the general telephone network communication connection rank of each base station, stores and manages it as data, and has a call connection request from the general telephone network. The purpose of the present invention is to provide a general telephone network call setup method in a satellite communication system that facilitates call setup and attempts to connect according to the stored communication connection priority in case of failure.

1 is a diagram showing an overall system configuration of a demand assignment multiple access (DAMA) satellite communication system.

2 is a view showing the configuration of a satellite system for explaining a general telephone network call setup method according to the present invention.

3 is a configuration diagram showing the configuration of the central control station 6 to which the present invention is applied.

4 is a configuration diagram schematically showing the configuration of the network control unit 40 of FIG.

FIG. 5 is a diagram illustrating memory mapping of the channel information storage unit 46 of FIG. 3.

Figure 6 is a flow chart for explaining a general telephone network call setup method in the satellite system according to the present invention.

<Description of the symbols for the main parts of the drawings>

1 satellite 2, 6 central control station

3: base station 5: communication connection sequence information storage unit

S: service channel T: traffic channel

11A, 11B, 11C: Switchboard 12A, 12B, 12C: Computer

13A, 13B, 13C: Terminal 14A, 14B, 14C: Facsimile

21 Antenna 22 Orthogonal Mode Converter (OMT)

23: low noise amplifier (LNA) 24: frequency down converter (DC)

25: Intermediate frequency combiner / distributor (IF C / D: IF Combiner / Distributer)

26, 31: SCPC (Single Channel Per Carrier) Channel Unit

32: Frequency Up Converter (UC) 33: High Power Amplifier (HPA)

40: network controller 41: processor

42: Service Channel Controller (SCC)

43: Dual Port RAM 44: Program Storage

45: base station information storage unit 46: channel information storage unit

50: network management system

In the satellite communication system according to the present invention for realizing the above object, a general telephone network call setup method receives and stores information of a general telephone network subscriber and a plurality of base stations respectively coupled with a plurality of subscribers, and based on this, In a satellite communication system including a central control station for controlling communication between base stations, a communication connection information request step for transmitting general telephone network communication connection information to each base station, and receiving general telephone network communication connection information from each base station. Communication connection information receiving step, communication connection information storing step of storing and managing the received general telephone network communication connection information database, call request receiving step of receiving call request from general telephone network subscriber through any base station, communication connection information database Read status information of called base station through Checking the communication target station to check whether the communication base station is currently in communication status, and if it is determined that the communication is not possible, the next next communication connection destination station to identify the designated next communication connection base station And a communication call setup execution step of establishing a communication call by executing a call connection through the designated base station in the next order according to the determined communication connection order.

According to the present invention having the above-described configuration, when a general telephone network subscriber requests a call connection through satellite communication, a central control station storing and managing general telephone network communication connection information of each base station performs a call connection through a base station that manages a call target. If it fails, the call connection is executed through the designated base station in the next order.

Therefore, the general telephone network subscriber can make a phone call with one call request through satellite communication, thereby increasing the call success rate.

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

Figure 2 shows the configuration of a satellite system according to the present invention, the same reference numerals are given to the same configuration as shown in Figure 1 and the detailed description thereof will be omitted.

In FIG. 2, reference numeral 5 denotes a communication connection sequence information storage unit in which base stations according to a communication access order are sequentially stored so that access can be made through a base station in a subsequent order according to a failure of a general telephone network communication connection. If there is a call request through the general telephone network from the base station 3n of the base station 3n, the base station in charge of the call connection target is searched through number translation, and if the call connection is executed through the call connection target base station, the call fails. According to the communication connection sequence information storage section 5, it is a central control station which performs reconnection of the general telephone network subscriber through the designated base station in the next order.

3 is a block diagram showing the configuration of the central control station 6 to which the present invention is applied.

In FIG. 3, reference numeral 21 denotes an antenna for transmitting and receiving an uplink signal and a downlink signal with respect to the satellite 1: 1, and 22 denotes a signal transmitted and received through the antenna 21 using a polarization property of frequency. Orthogonal Mode Transducer (OMT) 23 for separating and inputting and outputting a low noise amplifier (LNA) for low noise amplifying a downlink frequency signal of 12.25 to 12.75 GHz, for example, inputted through the Orthogonal Mode Transducer 22. Amplifier 24 denotes 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, the 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 ( IF C / D: IF Combiner / Distributer (IF C / D) which combines and outputs the intermediate frequency signal applied from SCU: 31, and 26 is an intermediate applied from this intermediate frequency combiner / distributer 25 An SCPC channel unit that demodulates, decodes, and outputs a frequency signal, wherein the intermediate frequency combination / distributor 25 is employed for system scalability when using a plurality of SCPC channel units.

Further, reference numeral 31 denotes an SCPC channel unit for encoding, modulating and outputting a message output from the network controller 40 to be described later, and 32 denotes an 70 MHz IF signal applied from the IF combination / distributor 25. For example, a frequency upconverter (UC) for converting into microwaves of 14.0 to 14.5 to generate an uplink frequency signal, and a high power amplifier (HPA) for amplifying an uplink frequency signal output from the frequency upconverter 32. High Power Amplifier).

Reference numeral 40 searches for a base station having a call connection target through number translation when there is a call request from a base station 3n through a general telephone network. If it fails, the network control unit executes the reconnection of the subscriber to the general telephone network through the designated base station in the next order.

In addition, reference numeral 50 is a network management system for the system administrator to manage the network control unit 40 to manage the overall network of the satellite communication system.

On the other hand, Figure 4 is a schematic diagram showing the configuration of the above-described network control unit 40, reference numeral 41 in the drawing is a processor for controlling the call processing between the base station, in particular, while controlling the entire system, 42 In addition to extracting packet information (Packet Information) from the message authorized from the SCPC channel unit 26 generates a S-ALOHA (Slotted ALOHA) packet, and the TDM (Time Division Multiplex) for the SCPC channel unit 31 Service Channel Controller (SCC) that generates and outputs messages from streams.

Further, reference numeral 43 denotes a dual port RAM, which is provided for data transmission and reception between the processor 41 and the service channel controller 42.

Reference numeral 44 is a program storage unit for storing the operation program of the processor 44, and 45 is a base station information storage unit for storing state information of each base station obtained by the polling operation of the network processor 41. Is a channel information storage unit for storing the use state of the communication channel allowed by the satellite.

Next, the operation of the satellite communication system having the above configuration will be described with reference to the flowchart shown in FIG. 6.

In the normal state, the network controller 40 of FIG. 3 performs a polling operation to check the state of each base station.

That is, the processor 41 of the network controller 40 writes packet data for checking the state of each base station into the dual port RAM 43, and the service channel controller 42 writes into the dual port RAM 43. After reading the written packet data, the TDM stream generates a message and outputs it to the SCPC channel unit 31.

Then, the SCPC channel unit 31 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 for each frequency in the IF combination / distributor 25, The frequency increasing converter 32 converts the uplink frequency signal of, for example, 14.5 GHz. The uplink frequency signal is output through the high power amplifier 33, the quadrature mode converter 22, and the antenna 21, and then transmitted to each base station 3 through the satellite 1.

Meanwhile, the response message received from the base station 3 through the satellite 1 to the antenna 21, that is, the downlink frequency signal of 12.25 GHz is transmitted through the orthogonal mode converter 22 and the low noise amplifier 23 to the frequency down converter. It is applied to (24) is converted into an intermediate frequency signal of 70 MHz, then applied to the SCPC channel unit 26 through the IF combination / distribution unit 25 is demodulated and decoded and then applied to the network control unit 40 .

The network controller 40 extracts packet information from the message to which the service channel controller 42 is applied to generate an S-ALOHA packet, and then writes the packet information into the dual port RAM 43. By reading the packet data from the port RAM 43 and updating and registering the base station information storage unit 45 based thereon, the state information for each base station is retained (step ST1). In addition, the above-described polling operation is continuously performed for each base station.

On the other hand, when there is a call request from any base station 3A connected to the general telephone network PSTN to another base station 3B during the above-described polling operation (step ST2), that is, the antenna of FIG. 21, when a message indicating a call request is received from the satellite 1 and corresponding packet data is input from the service channel controller 42 of the network controller 40, the processor 41 first starts the base station information storage unit ( It reads out the status information of the base station 3B called from 45 to determine whether the corresponding base station 3B is in a state where communication is possible (step ST3), and if it is determined that the communication is possible (step ST4), the channel The information storage unit 46 checks the currently available communication channel (ST5 step).

5 is a diagram illustrating memory mapping of the channel information storage unit 46. The channel information storage unit 46 has a storage area corresponding to the number of communication channels that satellites allow. Each storage area stores binary data of "0" or "1" depending on whether a corresponding communication channel is used. The binary data is changed and set by the processor 41 according to the use state of the communication channel.

In other words, when there is a call request from any base station 3A as described above, the processor 41 writes " 0 " to the channel information storage unit 46 when the busy state of the communication channel is " 1 ". By examining the communication channel and allocating it to the calling base station 3A and the called base station 3B, both base stations 3A and 3B can execute communication directly through this allocated communication channel (step ST6). .

However, when the base station 3B reads the state information of the base station 3B called from the base station information storage unit 45 and the base station 3B is currently in a state in which communication is impossible, the processor 41 stores the communication connection sequence information storage unit 5. On the basis of the communication connection sequence information stored in step S, the call request is executed to the next target base station 3C (step ST7).

Then, as described above, when the communication request is executed by executing the call request to the next target connection base station 3C (step ST8), the processor 41 allocates a usable communication channel through the channel information storage unit 46. By making the call possible, the next target connection base station 3C grasps the communication connection state of the corresponding terminal based on the call information received from the central control station 6, and the call request target through the exchange 11C. Will be connected to the subscriber of the public telephone network.

However, if the next target connection base station 3C is also in a communication unavailable state, the process returns to step ST7 again to execute a call request to the next target connection base station.

In addition, the communication channel allocation of the central control station 6 is performed by sending messages to both base stations 3A and 3C, and at this time, the corresponding area of the channel information storage unit 46 corresponding to the allocated communication channel. Is set to "1 " to refer to later assignment of a communication channel.

When the communication end message is transmitted from the calling base station 3A after the allocation of the communication channel, the processor 41 transmits a message indicating that communication has been completed for both base stations 3A and 3C in which communication has been performed. The communication end process is executed by setting the corresponding area of the channel information storage section 46 back to " 0 ".

That is, according to the above embodiment, when a general telephone network subscriber performs a call request to another general telephone network subscriber via satellite communication and is busy or fails to connect, the next step in which the central control station 6 of the satellite communication system is set is set. By making the connection through the communication target base station can increase the call success rate.

In addition, this invention is not limited to the said Example, It can variously deform and implement within the range which does not deviate from the technical summary of this invention.

As described above, according to the present invention, when a subscriber of a general telephone network makes a call or fails to access a call, the subscriber can make a call through a base station to be connected in the next order, thereby increasing the call success rate. The telephone network call setup method can be realized.

Claims (2)

In a satellite communication system equipped with a central control station that receives and stores information of a general telephone network subscriber and a plurality of base stations associated with a plurality of subscribers through satellites, and controls communication between arbitrary base stations based on the information. , Communication connection information request step of sending general telephone network communication connection information to each base station, A communication connection information receiving step of receiving general telephone network communication connection information from each base station, A communication connection information storage step of storing and managing the received general telephone network communication connection information as a database; A call request reception step of receiving a call request from a subscriber of a general telephone network through an arbitrary base station; Call target station checking step of checking the status information of the called base station through the communication connection information database to check whether the current communication status, A next step communication determination base station determination step of checking the communication possible state of the base station to be called and determining the next communication order target base station specified in the next order, And a communication call setup execution step of establishing a communication call by executing a call connection through a designated base station in a next order according to a designated communication access order. The method of claim 1, When the call connection with the general telephone network subscriber is failed through the base station of the next order according to the communication access order specified in the communication call setup execution step, through the base station of the next communication connection target according to the designated communication connection order again. A general telephone network call setting method in a satellite communication system, comprising performing a call connection with a subscriber of a general telephone network.

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