KR100215718B1 - Method of call setup and release using sub-band signaling in a satellite communication system - Google Patents

Abstract

The present invention relates to a call setup and release method using subband signaling in a satellite communication system that can set up and release a call using sub-band signaling, which is a communication network between base stations.

According to the present invention, when the minimum number necessary for call setup is input based on the called party number sequentially input from the calling party, the calling base station transmits the call setting number to the central control station, and then the communication channel allocated from the central control station. And by using the SCPC channel unit to send a confirmation message to the terminating base station and when receiving a response message from the terminating base station is to perform the call setup by sending the remaining number except the call setup number.

In addition, if the calling subscriber puts down the handset while both subscribers are communicating with each other and the base station is in communication, the calling base station sends a call cancellation message to the called base station, and when a response message is received from the called base station. In addition to sending the billing information message of the calling subscriber to the central control station, the call is released.

Thus, not only the call setup time can be shortened but also the call success rate can be improved to improve the performance of the system.

Description

Call setup and release using subband signaling in satellite communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using satellites. In particular, a call setup using subband signaling in a satellite communication system capable of establishing and releasing a call using subband signaling, which is a communication network between base stations, It is about a release method.

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 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.

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 controller which performs overall control of the base station. The base station controller 70 controls available SCPC channel units 66 _{1 to} 66 _n or communication channels received from the central station 2. It is possible to perform communication between subscribers through the central control by generating a predetermined S-ALOHA packet based on the base station information such as call setup state, channel usage state, billing information of the subscriber coupled to the base station 3 Control to output to the station (2).

Here, the polling message from the central control station, the polling response message from the base station, and the call request message are transmitted using the TDM channel and the S-ALOHA channel, respectively. It is called a service data network (SDN).

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.

Subsequently, when the communication channel and SCPC channel unit are allocated from the central control station 2, the base station 3 does not follow the management of the central control station 2 in subsequent communication. That is, after the call between the two subscribers is established, the base station 3 controls to perform mutual communication directly through the assigned communication channel and the SCPC channel unit.

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 and the communication modem are searched and assigned to the base station 3.

That is, when a call request message (off-hook) is input from the subscriber, the base station 3 generates a predetermined S-ALOHA packet to generate a predetermined S-ALOHA packet through the service data network (for example, the S-ALOHA channel). 2), the central control station 2 searches the currently available communication channel and the SCPC channel unit of the called station according to the call request message inputted from the base station 3, and transmits the communication channel and SCPC channel unit to the service data. The allocation to the base station 3 via a network (eg, TDM channel).

On the other hand, in general, the number of S-ALOHA packets transmitted from the base station 3 to the central control station 2 is 18, and among them, the number of packets (eg, random packets) for call request or call cancellation is 14 Limited to dogs.

Thus, the central control station, if a plurality of base stations continue to request a call, is performed by a call request signal that occurs frequently when each call setup operation is performed with each complete called party number entered by each calling subscriber. In addition to overloading, the performance of the system is not only deteriorated, but also the call setup time for each call can not be ignored, and thus many subscribers cannot be accommodated.

Accordingly, the present invention has been made in view of the above circumstances, and when the call request is received from the base station, the central control station establishes an approximate call (ring path) using only the minimum digit for call setup and then performs subband signaling. Call setup and release using subband signaling in a satellite communication system that can reduce call setup time, increase call success rate, and improve system performance by establishing or releasing a complete call by transmitting and receiving subsequent subscriber's numbers. The purpose is to provide a method.

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.

4 is an operation flowchart for explaining a call setup and release method using sub-band signaling in a satellite communication system according to an embodiment of the present invention.

* 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 70: base station control unit

In the satellite communication system according to the present invention for realizing the above object, a call setup method using subband signaling includes a plurality of base stations each coupled with a plurality of subscribers, and a central control station for managing and controlling the base stations. To; The calling base station stores the called party number sequentially input from the calling party in a predetermined memory, and if the minimum number necessary for call setting is input, the call base station sends the call setting number to the central control station; When a communication channel and SCPC channel unit are allocated from the station, an acknowledgment message sending step of sending an acknowledgment message to the destination base station using the assigned communication channel and SCPC channel unit, and when receiving a response message to the confirmation message from the destination base station, Characterized in that it comprises a remaining number sending step of transmitting the remaining number except the number sent in the call set number sending step.

In addition, in the satellite communication system according to the present invention, a method for canceling a call using subband signaling includes: a satellite communication system including a plurality of base stations each coupled with a plurality of subscribers, and a central control station for managing and controlling the base stations; When both subscribers are connected with each other base station and the calling subscriber sets down the handset, the calling base station sends the calling message to the called base station, and the calling base station sends the calling message from the called base station to the called message. Receiving a response message is characterized in that it comprises a charging information sending step of sending the charging information message of the calling subscriber to the central control station.

That is, according to the above configuration, the call request signal from the subscriber can be set up or released using subband signaling, which is a communication network between base stations, thereby minimizing the traffic volume of the service data network (SDN), thereby improving system performance. Will improve.

Next, a call setup and release method using subband signaling in the satellite communication system according to the present invention will be described in more detail using the operation flowchart of FIG. 4.

First, when an out-hook signal is input by the originating subscriber by picking up the handset (ST1 step), the base station controller 70 transmits the dialing tone to the calling party subscriber (ST2 step).

Then, when the called party number is input from the calling party (ST3 step), the base station controller 70 sequentially stores the incoming called party number in a predetermined memory (step ST4).

Subsequently, the base station controller 70 stores the called party number, which is continuously input from the calling party, in a predetermined memory, and when a minimum digit required for call setup is input (step ST5), the base station controller 70 determines the predetermined S- based on the digit. The ALOHA packet is generated and sent to the central control station through the S-ALOHA channel (step ST6).

On the other hand, the base station controller 70 sequentially stores the incoming subscriber number that is continuously input from the calling subscriber in the memory.

Subsequently, upon receipt of the subscriber's subscriber number from the base station 3, the central control station 2 searches for the currently available SCPC channel unit of each base station 3 jurisdiction over the currently available communication channel and originating / receiving subscriber. By making available the call request by broadcasting the available communication channel and SCPC channel unit to the destination base station, a call setup notification message including the available communication channel and the calling station SCPC channel unit is broadcast to the originating base station.

Subsequently, when the base station controller 70 receives the available communication channel and the SCPC channel unit from the central control station 2 (step ST7), the base station controller 70 confirms a predetermined basis based on the assigned communication channel through the assigned SCPC channel unit. A message (Confirm) is generated and broadcasted to the called base station (ST8 step).

Subsequently, when the originating base station 3 receives the response message for the confirmation message from the terminating base station (ST9 step), it transmits the remaining called party number to the base station except the called party number sent in the ST6 step (ST10 step). .

Subsequently, the receiving base station receiving the remaining called party number transmits a ring signal to a specific subscriber based on the complete called party number, and generates a predetermined packet message based on this called state and sends it to the calling base station. When the called state message is received from the called base station (step ST11), the calling base station transmits a ring back tone signal to the calling subscriber (step ST12).

On the other hand, the receiving subscriber is off-hook when the ring signal is sent from the receiving base station, and the receiving base station transmits the incoming response message to the calling base station, and the calling base station is called from the receiving base station. When the response message is received (step ST13), transmission of the ringback tone signal sent to the calling party is stopped (step ST14).

Thereafter, the originating subscribers are in a state of communication using subband signaling with each other (step ST15).

Subsequently, when the originating subscriber is on-hook by putting down the handset, the originating base station transmits the call cancellation message to the called base station (steps ST16 and ST17).

Subsequently, when the receiving base station receives the call cancellation message from the calling base station, the corresponding response message is sent to the calling base station. When the calling base station receives the response message from the called base station (ST18), the calling subscriber For example, the communication using the subband signaling is terminated by sending the charging information message including the calling number, the called number, the call start time, and the call end time to the central control station (step ST19).

On the other hand, when the called subscriber puts down the handset before the calling subscriber in step ST16, the called base station sends a call cancellation message to the calling base station. Thereafter, the originating base station sends the charging information message to the central control station to terminate the operation.

That is, according to the above embodiment, after the call is established through the central control station using only the minimum digit for call setup, direct communication between the base stations is performed, and even when the call is canceled, the call is exchanged between the base stations and the response message is exchanged. By releasing, traffic of the service data network (SDN), which is a communication network with the central control station, can be minimized.

Thus, the performance of the system is improved.

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, by using the subband signaling, which is the communication network between the base stations, the call can be set up and released, thereby minimizing the traffic volume of the service data network and increasing the call success rate, thereby improving the performance of the system. In the system, a call setup and release method using subband signaling 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 that performs system control through satellites to perform communication between subscribers; The calling base station stores the called party number, which is input from the calling party, in a predetermined memory in sequence, and when the minimum number necessary for call setting is input, sends the call setting number to the central control station; Sending a call setup number, and if the communication channel and SCPC channel unit is assigned, the confirmation message sending step of sending a confirmation message to confirm that the incoming call path is established using the assigned communication channel and SCPC channel unit, and Receiving a response message for the confirmation message Call setting method using a subband signaling in a satellite communication system comprising a remaining number sending step of transmitting the remaining number except the number sent in the call setting number sending step . 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 that performs system control through satellites to perform communication between subscribers; When the calling subscriber puts down the handset while both subscribers are in communication with each other base station, the calling base station sends the calling message to the called base station; The calling base station comprises a charging information sending step of sending a charging information message of the calling subscriber to the central control station when a response message for the call cancellation message is received from the called base station, using subband signaling in a satellite communication system. Inactivation method. The method of claim 2, The called base station transmits the dismissed message to the calling base station if the called subscriber puts down the handset without receiving the dismissing message from the calling base station; And transmitting the charging information message of the calling subscriber to the central control station when the calling base station receives the call canceling message from the called base station.