KR100210753B1 - Device for stuffing / destuffing control characters in satellite communication system - Google Patents

Abstract

The present invention provides a control character and pure information for specifying the start and end of a communication message in communication with a network management system that controls the overall network and a network control unit that collects base station information based on control signals from the network management system. The present invention relates to a stuffing / destuffing device for a control character in a satellite communication system that is configured to transmit and receive a control character so that data is not duplicated and to receive the changed control character. A network management system for performing overall network control and a satellite communication system including the network control unit; The network management system includes a polling signal generator for periodically outputting a polling signal to a data transmitter, a transmission message processing unit for generating and outputting a series of message formats when a polling signal is input, and transmission control of the message format. It is configured to include a stuffing processing unit for detecting and stuffing the character, the message receiving unit, characterized in that configured to include a de-stuffing processing unit for detecting and de-stamping the stuffed transmission control character when the message data is input; .

Description

Device for stuffing / despping of control characters 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 communication message is initiated in communication with a network control system that controls an overall network and a network control unit that collects base station information based on control signals from the network management system. The control character and the stuffing / dee in the satellite communication system are configured to transmit and control the control character so that the control character specifying the end and end and the pure information data do not overlap. It relates to a stuffing / destuffing device.

As the technology of data communication between terminals is developed, satellite communication, which allows two remotely located subscribers to communicate using satellites as a transmission medium, is becoming increasingly common. Since no separate signal line is required, it is mainly used as a long distance communication between countries or a communication method in a mountainous country.

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 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). Interface with terminals such as data terminals 13A and 13B and facsimile 14A and 14B, such as a computer, and the call function between the various terminals through data transmission / reception with the central control station 2. It provides a base station.

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 configuration, the central control station 2 transmits a control message through the service channel in a normal state, and then, based on a response message transmitted from the base station 3, that is, communication of the base station 3 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 a terminal having jurisdiction over the base station 3B, it is determined whether the 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 from the base station 3A through the service channel S, the central control station 2 receives the 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 and receiving satellite 1, an uplink signal, and a downlink signal, and 22 is an antenna 22 through the antenna 22 using a polarization property of frequency. Orthogonal Mode Transducer (OMT) 23 for separating and transmitting and receiving signals to be transmitted and received, 23 is a low-noise amplifier (LNA) for low-noise amplifying downlink frequency signals of 12.25 ~ 12.75 GHz input through the orthogonal mode converter (22) Low Noise Amplifier), 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, 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 SCPC (Single Channel Per Carrier) channel unit to be described later. SCU: an intermediate frequency combiner / distributor (IF C / D: IF combiner / distributer) for combining and outputting an intermediate frequency signal applied from 31), and 26 is an intermediate applied from this intermediate frequency combiner / distributor 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 IF signal of 70 MHz applied from the IF combination / distributor 25. For example, a frequency upconverter (UC) for converting the microwave into a microwave of 14.0 to 14.5 GHz to generate an uplink frequency signal, 33 is a high output amplifier for amplifying the uplink frequency signal output from the frequency upconverter 32 ( HPA: High Power Amplifier.

Reference numeral 40 denotes polling for checking the 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 the SCPC channel unit 26. In addition to performing a function, when there is a call request, the network control unit performs system control such as allowing both base stations to directly communicate with each other based on the information obtained during the polling process.

In addition, reference numeral 50 denotes a network management system for managing the overall network of the satellite communication system, in particular, the network control unit polling signal to ask whether there is data to be transmitted to receive the information of the base station from the network control unit 40 Output to (40).

Here, the SCUs 26 and 31 and the network controller 40 are collectively called a DMA (DAMA Management Processor), and a network management system that executes the system operation and network management function is called a DOP (DAMA Operation Processor). do.

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

In a normal state, the network controller 40 of FIG. 2 performs a polling operation to check the state of each base station to generate a series of TDM stream messages, and then output them 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 in FIG.

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 through 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 .

In addition, the network controller 40 generates a predetermined S-ALOHA packet for the response message from the base station 3 and updates it in each of the base stations by registering it in a memory means for storing base station information provided therein. It holds the status information.

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

In addition, the network control unit 40 outputs information on each base station 3 to a terminal server (not shown) of the network management system 50 through RS-232C. It is output to the DOP processor as a control unit through the LAN which is an internal communication line of the system.

Subsequently, when the DOP processor receives information about the network from the network controller 40 through the terminal server, the DOP processor takes a corresponding action based on an operation program and related data stored in a predetermined memory, and the predetermined operation is performed. The operator is notified through the display device of the operator, and the operator command is input through the man-machine interface which can be combined with the operator.

3 illustrates a format of a data frame used for communication between the network control unit 40 and the network management system 50 as described above, and FIG. 3A illustrates the format of the data frame. (B) shows the format of the information data area in the data frame A in detail.

In FIG. 3A, reference numeral STX (START OF TEXT) is a value indicating the start of a message and is recorded in hexadecimal 2, and reference numeral DATA is an area for recording user data to be carried in a frame.

In addition, the reference LRC MS (Longitudinal Redundancy Check Most Significant) is to perform an exclusive logical sum (XOR) for every even byte (BYTE) to detect a transmission error, the reference LRC Longitudinal Redundancy Check Last Significant Is an exclusive OR (XOR) on every odd byte (BYTE) to detect a transmission error.

In addition, the reference sign ETX (END OF TEXT) is a value indicating the end of the message is written in hexadecimal 3.

In (B) of FIG. 3, the reference numeral PACKET ID is an area for recording the unique number of the packet in the communication between the network management system 50 and the network control unit 40. The nature of the packet is a response signal according to data or data transmission. If it is (ACK), it is recorded as hexadecimal number 2. If it is a polling packet, it is recorded as hexadecimal 3 and if it is a polling response packet, it is recorded as hexadecimal 4.

The reference code MESSAGE ID is an area for recording a unique number of a message output from the network management system 50 to the network control unit 40 or each base station, and can take a value from 0 to 255.

In addition, reference numeral DATA LEN is an area for recording the size of data including user data, DATA LEN, and MESSAGE ID, and reference numeral DATA can be recorded up to 255 bytes as user data.

As described above, the communication between the network management system 50 in the central control station 2 and the network control unit 40 performs communication in the format of a data frame as shown in FIG.

However, if the code values of STX and ETX, which are transmission control characters for recording the start and end of the frame in the data frame format of FIG. 3, are hexadecimal 2 and 3, it can be seen that the following problem occurs.

That is, the information data recorded in the data area DATA of the data frame is composed of binary digits. When the predetermined data of the binary digits is recorded as 2 or 3, the data receiving apparatus receives the information. It is not possible to determine whether it is data or transmission control characters.

Accordingly, the present invention has been made in view of the above circumstances, and provides a communication message in communication with a network management system that controls the overall network and a network control unit that collects base station information based on control signals from the network management system. Stuffing of control characters in a satellite communication system in which the control characters specifying the start and end of the control characters are transmitted by changing the control characters so that the pure information data do not overlap, and the receiving device destructs the changed control characters. Its purpose is to provide a stuffing / destuffing device and a method thereof.

1 is an overall system configuration for explaining the 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.

3 is a view showing a structure of a frame to be transmitted and received.

Figure 4 is a functional block diagram showing the configuration of the stuffing / de-stamping apparatus of the control character in the 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 11A, 11B: switchboard

12A, 12B: Telephone 13A, 13B: Data Terminal

14A, 14B: Facsimile 21: Antenna

22: orthogonal mode converter 23: low noise amplifier

24: frequency down converter 25: intermediate frequency combination / distribution unit

26, 31: SCPC channel unit (SCU) 32: frequency up converter

33: high power amplifier 40: network control unit (DMP)

50: network management system (DOP) 51: timer

52: polling processing unit 53: transmission message processing unit

54: stuffing processor 55: message transmitter

56: message receiving unit 57: de-storping processing unit

58: received message processing unit 59: message dispatcher (Dispatcher)

40a: DOP processor

In one embodiment of the present invention for realizing the above object, a stuffing / destuffing apparatus of a control character in a satellite communication system is based on a network management system performing overall network control and a control command of the network management system. A satellite communication system having a network control unit for collecting information of a base station; The network management system includes a polling signal generator for periodically outputting a polling signal to a data transmitter, a transmission message processor for generating and outputting a series of message formats when a polling signal is input, and transmission control of the message format. It is configured to include a stuffing processing unit for detecting and stuffing the character, and the message receiving unit, characterized in that configured to include a de-ping processing unit for detecting and de-stamping the stuffed transmission control character when the message data is input; .

That is, according to the above configuration, data analysis is facilitated by stuffing transmission control characters that designate the start and end of the data frame so as not to overlap with pure information data.

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

FIG. 4 is a functional block diagram illustrating a configuration of a stuffing / destuffing apparatus for control characters in a satellite communication system according to an embodiment of the present invention.

In FIG. 4, reference numeral 51 denotes a timer for counting predetermined time data and outputs a result signal when a predetermined time elapses, and reference numeral 52 denotes a polling signal whenever a result signal is input from the timer 51. A polling processing unit 53 for outputting is a transmission message processing unit for generating and outputting a series of data formats according to a predetermined control signal, which generates a predetermined polling format especially when a polling signal is input from the polling processing unit 52. Will output this.

Reference numeral 55 denotes a message transmitter for outputting the polling data format input from the transmission message processor 54 to the processor 40a of the network control processor 40.

Further, reference numeral 56 denotes a message receiver for receiving a message input from the network control processor 40, and reference numeral 57 analyzes a stuffed transmission control molecule from data inputted through the message receiver 56 and analyzes the original message. De-storing processing for restoring the transmission control character of.

Further, reference numeral 58 denotes a reception message processing unit for processing a reception message, which is for processing data of a data frame restored from the de-stuffing processing unit 57, and reference numeral 59 is based on a predetermined control signal. Message dispatcher for outputting data to the appropriate device.

Reference numeral 40a denotes a processor provided in the network control processing unit 40 to execute overall network control processing.

Next, the operation of the device having the configuration of FIG. 4 will be described.

When a result signal of a predetermined level is input from the timer 51, the polling processing unit 52 outputs a polling request signal to the transmission message processing unit.

At this time, the code of the STX area for recording the start of the polling frame is stuffed through the stuffing processor 54 before the polling format is generated from the transmission message processor 53.

That is, since a transmission control character cannot come in a pure data area, the stuffing processing section 54 combines a pure STX (code: 02) having a size of 1 byte with another character to change the meaning of DLE (code: 10). Will be converted to a two-character array called B and code (42).

In addition, the stuffing processing section 54 divides the pure ETX (Code: 02), which is 1 byte in size, into two character arrays, a transmission control character called DLE (Code: 10) and C (Code: 43). Will print.

Then, the transmission message processing unit 53 outputs the codes of the start and end of the stuffed data frame.

On the other hand, when there is data input from the network control unit 40 through the message receiving unit 56, the receiving message processing unit 58 first retrieves the transmission control character from the data received through the de-stuffing processing unit 57 If the transmission control character for the start and end is detected in the stuffed form, the transmission control character is searched and if the transmission character B is detected after the transmission control character DLE, it is de-stamped as the transmission character 2.

In addition, the de-stuffing processing unit 57 searches for the transmission control character, and if the transmission character C is detected after the transmission control character DLE, de-stamping it to the transmission character 3.

Subsequently, the destuffed data is output to the corresponding device through the message dispatcher 59.

On the other hand, in order to know whether the transmission data is transmitted correctly, an error check code is inserted into the information data frame and transmitted. At this time, the error checking code used is 16-bit LRC Exclusive OR-ing. The calculated data is the data between STX and ETX and does not include the LRC itself. The LRC is calculated before stuffing the data at the time of transmission and at the reception before the stuffing of the data.

If the received LRC value is wrong, the data included in the data frame is discarded.

The method of calculating and recording the error check code described above can be simply expressed as follows.

LRC MS = Byte1 XOR Byte3 XOR .... XOR Byte (2n-1)

LRC LS = Byte2 XOR Byte4 XOR .... XOR Byte (2n)

In the above formula, Byte (n) means nth byte.

That is, according to the embodiment, as described above, stuffing the transmission control character notifying the start and end of the message to be different from the pure information data, and detecting and de-stamping the transmission control character from the data inputted by the stuffing process So that it does not overlap with.

On the other hand, the present invention is not limited to the above embodiments and can be implemented in various modifications without departing from the technical rights of the present invention.

As described above, according to the present invention, the start and end of the communication message are specified in the communication with the network control system which controls the overall network and the network control unit which collects information of the base station based on the control signal from the network management system. In the satellite communication system, the stuffing / de-stuffing of the control characters is performed in a satellite communication system that destructs the changed control characters and transmits them to the receiving device. Destuffing) device can be realized.

Claims (1)

A satellite communication system comprising a network management system for performing overall network control and a network control unit for collecting information of a base station based on a control command of the network management system; The network management system includes a polling signal generator that periodically outputs a polling signal to a data transmitter; A transmission message processing unit for generating and outputting a series of message formats when a polling signal is input, It comprises a stuffing processing unit for detecting and stuffing the transmission control character of the message format, Device for stuffing / de-stamping control characters in a satellite communication system, characterized in that it comprises a de-storing processing unit for detecting the stuffed transmission control character when the message data is input to the message receiving unit and de-stamping it.