KR0183269B1 - An usable modem searching method of satellite communication system - Google Patents

Abstract

In the present invention, when searching for an IDLE modem required for communication between subscribers in a satellite communication system, first, the modem state data is bundled by a predetermined number unit, and whether there is an effective modem therein is determined in detail. The present invention relates to a method and apparatus for valid modem searching of a satellite communication system, which is capable of executing an effective modem searching more quickly by checking whether each modem can be used. The central control station stores modem information in which a modem usage state is stored. Means, and a latch for temporarily storing the read modem state data, a comparison judgment means for comparing and judging whether the data temporarily registered in the latch are all at the first level, and outputting a predetermined determination signal according to the result, and the comparison judgment means. Control means for controlling whether to search the valid modem for each modem according to the level of the signal output from the Characterized in that configured to include.

Description

Effective Modem (SCU) Search Method for Satellite Communication System and Its Apparatus

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 the network control unit 40 in FIG.

4 is a memory map diagram of the modem information storage unit 47 in FIG.

5 is a block diagram showing the configuration of a network controller 40 in a satellite communication system according to an embodiment of the present invention.

6 is a flowchart for explaining an effective modem (SCU) search and modem allocation operation of a satellite communication system according to the present invention.

7 is a block diagram showing the configuration of the network controller 40 in the satellite communication system according to the second embodiment of the present invention.

8 is a memory map diagram of the modem state storage unit 48 shown in FIG.

* Explanation of symbols for main parts of the drawings

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 32: frequency up converter

33: high power amplifier 40: network control unit

41: processor 42: service channel controller

43: Dual Port RAM 44: Program Storage

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

47: modem information storage unit 48: modem state storage unit

50: network management system 60: processor

70: latch 80: comparison

The present invention relates to a communication system using a satellite, and in particular, in searching for an IDLE required for communication between subscribers, first, by checking whether there is an effective modem available therein by binding modem state data in a predetermined number unit. The present invention relates to a method and apparatus for searching for an effective module of a satellite communication system, which enables to execute an effective modem search more quickly by checking whether each modem can be used in detail according to the result.

With the rapid development of communication technology, satellite communication, which enables subscribers who are located in remote areas to make calls through satellites, is becoming increasingly common. Since such satellite communication does not require a separate signal line for communication, It is usefully used as a long distance communication between countries or as a communication method in a mountainous country such as Korea. In the satellite communication, there are two types of PAMA (Pre Assignment Multiple Access) method for allocating communication channels for each subscriber according to the channel assignment method and Demand Assignment Multiful Access (DAMA) method for allocating communication channels according to the subscriber's request. 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 denotes a satellite having a plurality of communication channels, 2 denotes a central control station for controlling the entire satellite communication system, and 3 (3A, 3B) denotes an exchange 11A, 11B or a telephone 12A, 12B. And a 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 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 communicates the state of each base station 3 based on a response message transmitted from the base station 3. It performs a polling function to check the available capacity or the utilization status of the communication channel. And, if the base station 3B jurisdiction from the specific base station, for example, the base station 3A has a call request for the terminal, it is determined whether the corresponding 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 provided to both base stations 3A. 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 denotes an antenna for transmitting and receiving the satellite 1, an uplink signal, and a downlink signal, and 22 denotes an antenna 22 using frequency polarization characteristics. Orthogonal Mode Transducer (OMT) for separating and transmitting and receiving signals transmitted and received through 23, 23 is a low noise amplifier for low-noise amplifying the downlink frequency signal of 12.25 ~ 12.75 GHz input through the orthogonal mode converter (22) Low Noise Amplifier (LNA), 24 is a frequency down converter (DC) which converts 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 ( SCU: an intermediate frequency combiner / distributor (IF C / D: IF combiner / distributer) for combining and outputting an intermediate frequency signal applied from SCU: 31, and 26 is an intermediate frequency 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 / distribution unit 25 is employed for system scalability when using a plurality of SCPC channel units.

Also, 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: Up Converter) for converting microwaves into microwaves of 14.0 to 14.5 GHz to generate an uplink frequency signal, and a high output amplifier (HPA) for amplifying an uplink frequency signal output from the frequency upconverter 32. : High Power Amplifier.

Reference numeral 40 denotes a polling function for checking a state of the 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. If there is a call request from a specific base station, based on the information obtained during the polling process, it is determined whether the other base station is in a communication state. It is a network control unit that performs system control, such as by assigning a modem to both base stations so that both base stations can 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.

On the other hand, Figure 3 is a schematic diagram showing the configuration of the above-described network control unit 40, in the drawing is a processor for controlling the entire reference numeral 41 sound system, in particular, the call processing between the base station, 42 is the SCPC channel The packet information is extracted from the message authorized by the unit 26 to generate a slotted ALOHA (S-ALOHA) packet, and a time division multiplex (TDM) stream for the SCPC channel unit 31 is generated. Service Channel Controller (SCC) that generates and outputs messages from

Reference numeral 43 is also 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 40. Is a channel information storage unit for storing the use state of the communication channel allowed by the satellite, 47 is a modem information storage unit for storing information on the modem use state of each base station.

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 performs a polling operation to check the state of each base station.

That is, the processor 41 of the network control unit 40 writes packet data for checking the state of each base station in the dual port RAM 43, and the service channel controller 42 writes in 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 32, and the antenna 21, and then transmitted to each base station 3 through the satellite 1 in FIG. .

On the other hand, the response message received by the antenna 21 from each base station 3 via the satellite 1, that is, the downlink frequency signal of 12.25 GHz 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 a 70 MHz intermediate frequency signal, and then applied to the SCPC channel unit 26 through the IF combination / distributor 25 to be demodulated and decoded and then applied to the network controller 40. do.

In addition, 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 on this, the state information for each base station is retained.

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 any base station to any other base station during the above-described polling operation, that is, a message indicating the call request from the satellite 1 is received through the antenna 21 of FIG. When the packet data is input from the service channel controller 42 of the network controller 40, the processor 41 first reads the state information of the base station called from the base station information storage unit 45, and the base station currently communicates. In this case, if it is determined that the communication is possible, the channel information storage unit 46 and the modem information storage unit 47 are checked to determine the currently available communication channel and modem (SCU). .

4 is a diagram showing memory mapping of the modem information storage unit 47. The modem information storage unit 47 has a storage area corresponding to the number of modems of each base station, and each storage area has a storage area corresponding thereto. Binary data of 0 or 1 will be stored depending on whether the corresponding communication modem is used. The binary data is changed and set by the processor 41 according to the use state of the communication modem.

That is, when there is a call request from any base station, when the busy state of the communication modem is 1, the processor 41 checks the communication modem written with 0 in the modem information storage unit 47 and calls it with the calling base station. By assigning the allocated base stations, both base stations can perform communication directly through the assigned communication modem. On the other hand, this communication modem is allocated by sending a message to both base stations. At this time, the corresponding area of the modem information storage unit 47 corresponding to the allocated communication modem is set to 1, so that the communication modem is assigned at a later time. Will be referenced.

When the communication end message is transmitted from the calling base station after allocating the communication modem, the processor 41 transmits a message indicating that the communication is terminated to both base stations where the communication has been performed, and the modem information storage unit 47 transmits a message. By setting the area back to zero, the communication termination process is performed.

However, in the above-described satellite communication system, the processor 41 checks whether the modem can be used for each modem on the basis of a specifically designated location such as 'first address' of the memory map shown in FIG. There is an inefficiency in searching for valid modems because it is to be verified.

Accordingly, the present invention was created in view of the above circumstances, and in searching for an effective IDLE modem necessary for inter-subscriber communication, first, by checking the presence or absence of an effective modem in the modem unit, the modem status data is bundled in a predetermined number unit. It is an object of the present invention to provide a method and apparatus for valid modem searching of a satellite communication system, which enables the effective modem searching to be executed more quickly by checking whether the modem can be used in detail according to the results.

The effective modem search method of the satellite communication system according to the first aspect of the present invention for realizing the above object is a satellite capable of performing communication between any base station by combining a plurality of base stations respectively coupled to a plurality of subscribers through satellites. In the communication system, when there is a call request from a base station, a modem status information latch step of reading and latching modem status information in a predetermined byte unit at a time, and comparing and determining whether the latched modem status data are all '1'; According to the comparison decision result, it characterized in that it comprises a valid modem whether to verify whether the valid modem for each modem.

In addition, the effective modem search apparatus of the satellite communication system according to the second aspect of the present invention for realizing the above object, a plurality of base stations each coupled with a plurality of subscribers, satellites for providing a communication channel between each base station, and a call A satellite communication system having a central control station for assigning and controlling a modem usable for a base station on request, the satellite communication system having the central control station, wherein the central control station stores a state of use of the communication modem. A modem information storing means, a latch for temporarily storing the read modem state data, a comparison judging means for comparing and judging whether the data temporarily registered in the latch are all at the first level, and outputting a predetermined determination signal according to the result; Control means for controlling to search for valid modem for each modem according to the level of the signal output from the comparison judging means And it characterized in that configured.

That is, according to the present invention having the above-described configuration, when searching for the IDLE modem required for inter-subscriber communication, first, the modem state data is bundled in a predetermined number unit to check whether there is an effective modem therein, and then Therefore, by checking the availability of each modem in detail, effective modem search can be executed more quickly.

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

FIG. 5 is a block diagram showing an effective modem searching apparatus of a satellite communication system according to an embodiment of the present invention. In FIG. 5, parts having substantially the same functions as those of FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. do.

In FIG. 5, reference numeral 70 denotes a latch for temporarily storing modem state data in units of 1 byte read out from the modem information storage unit 47 according to a control command of the processor 60, which will be described later. It is determined whether the data values temporarily registered in the ranch 70 are all '1', and according to the result of the determination, for example, if all are '1', a high level determination signal is determined, and if any one is '0', a low level determination is made. It is a comparison judgment outputting signal.

On the other hand, reference numeral 60 is a processor that executes the monitoring function of the communication modem, which reads modem status data in units of 1 byte from the modem information storage unit 47 when there is a call request from an arbitrary base station, and the latch 70. After a temporary registration, it is a processor that performs effective modem search for each modem in accordance with the level value of the determination signal applied from the comparison edition unit 80.

Next, the operation of the system having the above-described configuration will be described in more detail using the flowchart shown in FIG.

In FIG. 5, when a call request message from any base station is input to the processor 60 through the service channel controller 42 (step ST1), the processor 60 first calls from the base station information storage unit 45. The status information of the base station to be requested, that is, the called base station, is read (step ST2) to determine whether the base station is in a state where a current call is possible (step ST3).

When the base station called in step ST3 is determined to be in a callable state, the modem state data is read out from the modem information storage unit 47 and stored in the latch 70 at the same time. (Step ST5), the comparison decision unit 80 compares and determines whether all 8 bits are '1'. (ST6 step)

If it is confirmed that all of the comparison results are '1' (ST7 step), since there is no modem available, the above checking operation is repeated until the valid modem is confirmed within the byte unit by increasing the address by 1 byte. (ST8 step), the processor 60 does not perform modem search for each bit (modem) until all the modem status is confirmed to be '1' (ST9 step).

When the available modem is found as a result of the search (at step AT10), the processor 60 sends a message to both stations to allocate the call modem (step ST11), and then transmits the corresponding address data of the modem information storage unit 46. By changing to 1 ', call request processing is terminated. (ST13 step)

That is, according to the above embodiment, in searching for an IDLE modem required for inter-subscriber communication, first, the modem state data is bundled in a predetermined number unit to check whether there is an effective modem therein, and then, according to the result, each detail is determined in detail. By checking the availability of each modem, the effective modem search can be executed more quickly.

On the other hand, the above-described effective modem search procedure is based on the assumption that the device configuration of each base station is operating normally, but in reality, there may be a partial malfunction in any part of the satellite communication system which is complicated and extensive. Therefore, even in the field of managing effective modem (SCU), more efficient operation plan is needed.

7 is a block diagram showing a second embodiment of the present invention constructed in view of the above circumstances. In comparison with the configuration of the first embodiment shown in FIG. 5, reference numeral 48 denotes a modem in which the processor 60 of the central control station 2 is reported from a processor (not shown) of the subordinate base station during polling. (SCU) A modem state storage unit for identifying and separately managing a modem (SCU) showing normal operation based on state information. In general, the number of modems (SCU) that a single base station can accommodate to the maximum is 32. In view of the above, in the case of the satellite communication network composed of N base stations, memory mapping therein is illustrated in FIG. 8.

That is, for example, when a modem (SCU) that operates abnormally in the No. 2 SET among the N (SCU) subordinate base stations (SCU) is identified, the processor (not shown) of the base station is connected to the central control station ( This is reported to the processor 60 side of 2), the processor 60 of the central control station 2 based on this data of the corresponding modem address of the modem state storage unit 48 as illustrated in FIG. Is set to '1' to exclude the corresponding modem (SCU) first when assigning a modem (SCU) by call setup request.

Therefore, according to the second embodiment, the processor 60 of the central control station 2 first checks the modem state storage unit 48 when there is a call setup request. By selecting the modem (SCU), that is, the modem in the normal operating state, and later setting the effective modem (SCU) in the same manner as described in the above-described embodiment 1, it is possible to perform more efficient modem (SCU) management .

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, when searching for an IDLE modem required for inter-subscriber communication, first, the modem state data is bundled in a predetermined number unit to check whether there is an effective modem therein, and then, according to the result, detailed information is performed. By checking the availability of each modem, it is possible to realize the effective modem searching method and apparatus of the satellite communication system that can perform the effective modem searching more quickly.

Claims (4)

In a satellite communication system in which a plurality of base stations, each of which is combined with a plurality of subscribers, are connected via satellite to perform communication between arbitrary base stations, when the call request of any base station is requested, modem status information of a predetermined byte unit is temporarily suspended. The modem status information latch step of reading and latching the data, the comparison decision step of comparing and determining whether the latched modem status data is all '1', and the valid modem checking step of checking the valid modem for each modem according to the comparison decision result. Effective modem search method of a satellite communication system comprising a. 2. The method of claim 1, further comprising a normal modem checking step for screening a normal operation modem (SCU) prior to executing the modem status latching step. A satellite communication system having a plurality of base stations, each coupled with a plurality of subscribers, a satellite for providing a call channel between each base station, and a central control station for allocating and controlling a modem (SCU) usable for a base station with a call request. The central control station compares the modem information storage means for storing the state of use of the modem, the latch for temporarily storing the read modem state data, and whether the data temporarily registered in the latch are all at the first level. And a comparison means for outputting a predetermined determination signal according to the result, and a control means for controlling to search for a valid modem for each modem according to the level of the signal output from the comparison determination means. Valid modem detection device. [4] The effective modem of the satellite communication system according to claim 3, further comprising a modem state storage unit for storing operation state information indicating whether the modem is in normal operation in order to separately manage a normal operation modem (SCU). Search device.