KR19980014385A - Channel reservation allocation method in satellite communication system - Google Patents

Abstract

The present invention relates to a channel reservation allocation method (PMA) in a satellite communication system for searching for a satellite channel and allocating a currently available channel when a reserved time for a satellite channel is reserved in a reservation allocation method (PAMA) A satellite communication system having a man-machine interface adapted to input data call data by a channel reservation allocation method (PAMA) by combining a satellite communication system and a system operator, the satellite communication system comprising: A data storing step of storing data call data such as a channel use time inputted through the man-machine interface in a predetermined memory; a time comparison step of comparing current time data with reserved time data; A channel existence checking step of determining whether a currently available channel exists, a call setting step of setting a call through a corresponding channel when an available satellite channel exists, And a call release step.

Description

Channel reservation allocation method in satellite communication system

The present invention relates to a communication system using a satellite, and more particularly, it relates to a communication system using a satellite, in which when a time to use a satellite channel is reserved in a reservation allocation method (PAMA) of a satellite channel, To a channel reservation allocation method in a satellite communication system.

In recent years, with the rapid development of communication technology, satellite communication that enables subscribers located at a remote place to make calls through a satellite is gradually becoming common. Such satellite communication is useful for long distance communication between countries, or communication method of a mountainous country like Korea because a separate signal line is not required for communication.

The satellite communication includes a PAMA (Pre-Assignment Multiple Access) scheme in which a corresponding channel is reserved according to a channel allocation request to be used by a subscriber according to a channel allocation scheme, and a PAM And a Demand Assignment Multiple Access (DAMA) method.

1 is a block diagram showing the overall system configuration of a satellite communication system according to the PAMA scheme.

In FIG. 1, reference numeral 1 denotes a satellite having a plurality of communication channels, reference numeral 2 denotes a central control station for controlling the entire satellite communication system, reference numerals 3A and 3B denote data terminals such as exchangers, And is a base station having an interface function with respect to the terminal and providing a call function between the various terminals through data transmission / reception with the central control station 2.

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

In the above configuration, the central control station 2 transmits a control message through the service channel S and then grasps the state of each base station 3 based on a response message transmitted from the corresponding base station 3 . That is, the base station 3 performs a polling function for checking the communication capacity of the base station 3 and the use state of the communication channel. When there is a call request from a specific base station, for example, a base station 3A to a terminal of another base station 3B, the base station 3B can communicate with the base station 3B based on the information obtained in the polling process And in the case of the communication enabled state, the traffic channels T available to the satellites are allocated to the base stations 3A and 3B so that the base stations 3A and 3B can directly communicate with each other .

On the other hand, the central control station 2 has a data call function such as a reservation time, a subscriber number, an access mode such as a synchronous or asynchronous mode, and a communication speed in addition to a predetermined signal for reserving an allocation of a satellite channel by an operator The data call data is stored, and when the reserved allocation time is reached based on the data, the control of communication between the base stations is controlled.

Then, when the reserved allocation time of the channel set by the operator has elapsed, the central control station 2 cancels the traffic channel T that was provided for both base stations 3A and 3B by executing the communication end process for both base stations .

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

Reference numeral 21 in FIG. 2 denotes an antenna for transmitting / receiving an uplink signal and a downlink signal with the satellite 1 and reference numeral 22 denotes an antenna for transmitting / receiving an uplink signal and a downlink signal through the antenna 21 An orthogonal mode transducer (OMT) 23 for separately inputting and outputting signals to be transmitted and received, a low noise amplifier 23 for low-noise amplifying a downlink frequency signal of, for example, 12.25 to 12.75 GHz inputted through the orthogonal mode converter 22 LNA (Low Noise Amplifier), and 24 is a frequency down converter (DC) for converting a frequency signal applied through the low noise amplifier 23 to an intermediate frequency signal IF of, for example, 70 M Hz.

Reference numeral 25 denotes a frequency division multiplexer for separating and outputting an intermediate frequency signal IF applied from the frequency down converter 24 to a plurality of intermediate frequency signals and outputting a single channel per channel (SCPC) channel unit (IF C / D: IF Combiner / Distributor) 26 for outputting an intermediate frequency signal applied from the intermediate frequency combining / distributing unit 25, Demodulates, decodes and outputs the frequency signal, and encodes and modulates a message output from the network control unit 40, which will be described later, and outputs the message.

Here, the intermediate frequency combining / distributing unit 25 is employed for system scalability in the case of using a plurality of SCPC channel units, and the number of the SCPC channel units 26 is generally 32.

Reference numeral 27 denotes a frequency up-converter (UC) for converting an IF signal of 70 MHz applied from the IF combining / distributing unit 25 into a microwave of, for example, 14.0 to 14.5 GHz to generate an uplink frequency signal. And 28 is a high power amplifier (HPA) for amplifying an uplink frequency signal output from the frequency up converter 27.

Reference numeral 40 indicates a state of each base station 3 based on a response message transmitted from the corresponding base station after transmitting a control message to each base station 3 through an arbitrary SCPC channel unit 26 _{1 to} 26 _N The network controller controls the polling function. The network control unit 40 allocates the available traffic channel T and the modem when the channel allocation command according to the data call (DATA CALL) is input from the network management system 50 to be described later, So that the system control can be performed.

Reference numeral 50 denotes a network management system for the system manager to manage the overall network of the satellite communication system by managing the network control unit 40. The network management system 50 controls the network controller 40 based on the data call data input by the operator to perform communication between the base stations.

3 is a functional block diagram showing a configuration of the network management system 50. Reference numeral 51 denotes a processor for controlling a data call function such as execution control of channel reservation set by an operator And reference numeral 52 is an information exchange device between the satellite communication system and the operator for operating it, that is, a man-machine interface (MMI) for the operator to confirm information from the system and input operation commands of the system.

Reference numeral 53 denotes a terminal server for transmitting / receiving a signal to / from the network control unit DMP, which communicates with each other through a physical communication link in accordance with the communication protocol of the network control unit DMP and the RS-232C.

In addition, reference numeral 54 denotes a processor that outputs a predetermined signal to the processor 51 so that a data call (DATA CALL) is performed based on a series of data call data input by an operator at a corresponding time The data call real-time processing unit includes timer means for counting time itself. Reference numeral 55 denotes a data call real-time processing unit that allocates a satellite channel so that a data call (DATA CALL) can be performed using a satellite, Call execution unit.

Reference numeral 56 denotes a data call storage unit for storing data call data input to the operator under the control of the processor 51. Reference numeral 57 denotes a data call storage unit in which an operator performs a data call A subscriber number, a communication speed, and the like, and stores the received data temporarily.

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

In a normal state, the network controller 40 of FIG. 2 performs a polling operation to check the status of each base station.

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

Then, the corresponding SCPC channel unit 26 encodes and modulates the message to output an intermediate frequency signal. The intermediate frequency signal is combined on a frequency-by-frequency basis in the IF combining / distributing unit 25, (27) to an uplink frequency signal. The uplink frequency signal is output through the high-power amplifier 28, the orthogonal mode converter 22 and the antenna 21, and then transmitted to the base stations 3 through the satellite 1 in FIG.

The response message signal received from each base station 3 via the antenna 1 to the antenna 21 is applied to the frequency down converter 24 through the orthogonal mode converter 22 and the low noise amplifier 23 to be transmitted at a frequency of 70 MHz And is then applied to an arbitrary SCPC channel unit 26 through the IF combination / distribution unit 25, demodulated and decoded, and then applied to the network control unit 40. [

Then, the network controller 40 extracts the packet information from the received message, generates S-ALOHA packets, and updates and registers the predetermined base station information storage unit based on the generated S-ALOHA packets, thereby holding status information on all base stations.

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

Meanwhile, FIG. 4 is an operation flow chart for explaining a PAMA method of allocating a channel. Referring to FIG. 4, the operation of the network management system 50 is focused on, Explain the call (DATA CALL).

First, when data for a data call is input by the operator, the processor 51 temporarily stores the data in the data call reserving unit 57 (steps ST51 and ST52). Here, the data for the data call may include a time to reserve a channel, an end time, a subscriber number, a synchronous or asynchronous connection mode, and a communication speed.

Then, the processor 51 determines that the input channel reservation time is the future time (ST53). In addition, if the channel reservation time is the future, it is determined whether the inputted calling subscriber number and called subscriber number exist normally (ST54). Then, the processor 51 transmits the data call data input through the man-machine interface 52 by the operator to the data call storage 52 when the inputted data call data is in the future and the subscriber number normally exists (Step ST55). Thereafter, the processor 51 controls the data call real-time processing unit 54 to count the predetermined time data separately from the counting of the current time data.

Then, the processor 51 continuously compares the time data counted separately from the current time data. For example, if the reserved time is five minutes before the reserved time, the currently available channel is searched and if the corresponding channel exists, And stores it in a predetermined memory area of the data call storage unit 56 (ST56, 57, and 58).

Then, the processor 51 searches for a signal input from the data call real-time processing unit 54. When a result signal resulting from the arrival of the reservation time from the data call real-time processing unit 54 is input (ST59) To the network control unit 40, an instruction to set the call through the reserved channel for the data call. Then, the network controller 40 sets a call between the base stations through the corresponding channel (ST60).

The data call real-time processing unit 54 outputs the result signal to the processor 51 in step ST61 when the reserved data is terminated. In this case, the processor 51 transmits a signal to the network controller 40 To output a predetermined control command. Then, the network controller 40 releases the call of the communication base station (ST62).

The reserved channel allocation method (PAMA) operated as described above has a problem that the user can not use the channel reservation until the reservation time (several weeks or several hours) after the request for channel reservation is made by the operator. This results in wasting communication resources that are important in satellite communication.

Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method and apparatus for searching for a satellite channel when a reserved time is reserved, The present invention provides a method of allocating a channel reservation in a satellite communication system that allocates a channel to a mobile station.

1 is a general system configuration diagram for explaining an outline of a general satellite communication system;

Fig. 2 is a functional block diagram showing the configuration of the central control station 2 in Fig. 1. Fig.

3 is a functional block diagram showing the configuration of the network management system 50 in Fig.

FIG. 4 is an operation flow chart for explaining a reservation allocation method (PAMA) of a general satellite channel; FIG.

FIG. 5 is a flowchart illustrating a channel reservation allocation method in a satellite communication system according to an embodiment of the present invention. FIG.

* A brief description of the main parts of the drawing

1: satellite 2: central control station

3A: base station 21: antenna

22: orthogonal mode converter 23: low noise amplifier

24: frequency down converter 25: intermediate frequency combination /

26: SCPC channel unit 27: frequency up converter

28: high power amplifier 40: network controller

50: Network Management System

51: Processor 52: Man-Machine Interface (MMI)

53: Terminal server 54: Data call real-time processing section

55: data call performing unit 56: data call storing unit

57: Data call reservation unit

In order to achieve the above object, a channel reservation allocation method in a satellite communication system according to the present invention is a method for allocating a channel call reservation (PAM) data by combining a satellite communication system with a system operator, 1. A satellite communication system having a machine interface, comprising: A data storing step of storing data call data such as a channel use time inputted through the man-machine interface in a predetermined memory; a time comparison step of comparing current time data with reserved time data; A channel existence checking step of determining whether a currently available channel exists, a call setting step of setting a call through a corresponding channel when an available satellite channel exists, And a call release step.

Next, the above method will be described in more detail with reference to FIG.

5 is a flowchart illustrating a channel reservation allocation method in a satellite communication system according to an embodiment of the present invention.

First, when data for a data call is input by the operator, the processor 51 temporarily stores the data in the data call reservation unit 57 (ST61, ST62). Here, the data for the data call may include a time to reserve a channel, an end time, a subscriber number, a synchronous or asynchronous connection mode, and a communication speed.

Then, the processor 51 determines that the input channel reservation time is the future time (ST63). Also, if the channel reservation time is the future, it is determined whether the entered calling subscriber number and called subscriber number exist normally (ST64).

Then, the processor 51 transmits the data call data input through the man-machine interface 52 by the operator to the data call storage 52 when the inputted data call data is in the future and the subscriber number normally exists (Step ST65). Thereafter, the processor 51 controls the data call real-time processing unit 54 to count the predetermined time data separately from the counting of the current time data.

Then, the processor 51 continuously compares the time data counted separately from the current time data. When the reserved time is reached, the processor 51 searches the presently available channel, and if there is a corresponding channel, (Step ST66, step 67, step 68).

After that, the data call real-time processing unit 54 outputs the result signal to the processor 51 when the reserved time ends (ST69). At this time, The control unit 40 outputs a predetermined control command. Then, the network control unit 40 releases the call of the communication base station (ST70).

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the technical scope of the present invention.

As described above, according to the present invention, when reserving a time to use a satellite channel in a reservation allocation method (PAMA) of a satellite channel, a satellite communication The system can realize the channel reservation allocation method.

Claims (2)

A satellite communication system having a man-machine interface adapted to input data call data by a channel reservation allocation method (PAMA) by combining a satellite communication system and a system operator, the system comprising: A data storage step of storing data call data such as a channel use time input through the man-machine interface in a predetermined memory; A time comparison step of comparing the current time data with the reservation time data, A channel existence checking step of determining whether a presently available channel exists if the current time data and the reservation time data coincide with each other, A call setup step of setting up a call through a corresponding channel when an available satellite channel exists, And canceling the call when the reservation time is terminated. The method as claimed in claim 1, And if there is no currently available channel, continues until there is a next available channel.