KR0183270B1 - An usable modem searching method of satellite communication system - Google Patents

Abstract

The present invention is biased to a specific modem (SCU) by specifying the location of the test modem according to the random number calculation result using a random function in searching for an IDLE modem required for communication between subscribers in a satellite communication system. The present invention relates to a method and apparatus for valid modem search of a satellite communication system that can prevent modem search or modem assignment from being performed. The random number is generated by using a random function and then generated. And a step of searching for an unused communication modem based on the calculation result when a call request is received from an arbitrary base station by calculating a designated value for designating a corresponding test position for the modem information storage means on the basis of the calculation result. Characterized in that configured.

Description

Method and apparatus for searching effective modem (SCU) in satellite communication system

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 shown in FIG.

3 is a block diagram showing the detailed configuration of the network controller 40 shown in FIG.

4 is a memory map diagram of the modem information storage unit 47 shown 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 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

12, 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, 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: random number generator 80: check position designation calculator

The present invention relates to a communication system using satellites, and in particular, in searching for an effective IDLE modem required for inter-subscriber communication, by specifying a location of a test modem according to a random number calculation result using a random function. The present invention relates to a method and apparatus for searching for an effective modem of a satellite communication system that can be prevented from performing a modem search or a modem assignment due to a specific modem.

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 satellite communication, there are two types of PAMA (Pre Assignment Multiple Access) method for allocating communication channels for each subscriber according to the channel allocation method, and DAMA (Demand Assignment Multiful Access) method for allocating communication channels according to 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 an artificial radio having a plurality of communication channels, 2 denotes a central control station that controls the entire satellite communication system, and 3 (3A, 3B) denotes an exchange 11A, 11B or a telephone 12A, 12B), data terminals 13A, 13B such as a computer, and facsimile 14A, 14B, and other interface functions, and communication between the various terminals through data transmission and reception with the central control station 2; A base station that provides functionality.

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. When there is a call request from the base station 3A to the base station under the jurisdiction of the base station 3B, the base station 3B determines whether the base station 3B is in a state in which communication is possible based on the information obtained during the polling process. In the case of a communicable state, the available traffic channels T of the satellites are 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 22 using frequency polarization characteristics. Orthogonal Mode Transducer (OMT) 23 for separating and inputting and receiving signals transmitted and received through a low noise amplifier for low noise amplifying downlink frequency signals of 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. IF C / D: IF Combiner / Distributer (IF C / D) which combines and outputs the intermediate frequency signal applied from SCU: 31, and 26 is an intermediate applied from this intermediate frequency combiner / distributer 25 An SCPC channel unit that demodulates, decodes, and outputs a frequency signal, wherein the intermediate frequency combination / distributor 25 is employed for system scalability when using a plurality of SCPC channel units.

Further, reference numeral 31 denotes an SCPC channel unit for encoding, modulating and outputting a message output from the network controller 40 to be described later, and 32 denotes an 70 MHz IF signal applied from the IF combination / distributor 25. For example, a frequency up-converter (UC: Up Converter) for converting 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 up-converter 32. : High Power Amplifier.

And, reference numeral 40 is a polling function that checks the state of each base station 3 based on a response message transmitted from the base station 3 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, the other base station determines whether the other base station can communicate with each other based on the information obtained during the polling process. ) Is a network control unit that performs system control such as assigning a modem (SCU) 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, reference numeral 41 in the drawing is a processor that controls the entire system, in particular call processing between the base station, 42 is the SCPC channel Packet information is extracted from the message authorized by the unit 26 to generate a slotted packet (S-ALOHA) packet, and a time division multiplex (TDM) stream for the SCPC channel unit 31. 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, a message of the TDM stream is generated and outputted 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 by frequency in the IF combination / distributor 25 and then frequency. Increment conversion section 32 is converted to an uplink frequency signal of, for example, 14.5GHz. 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 to the frequency down converter. The signal is applied to (24) and converted into an intermediate frequency signal of 70 MHz, and then applied to the SCPC channel unit 26 through the IF combination / distributor 25, demodulated and decoded, and then applied to the network controller 40.

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. The packet data is read from the port RAM 43, and the base station information storage unit 45 is updated and registered based on the packet data, thereby retaining state information for each base station.

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 usage state of the modem SCU.

That is, when there is a call request from any base station, the processor 41 checks the modem written with 0 in the modem information storage unit 47 when the communication modem is in use state 1 and calls it with the calling base station. Assignment to the base station allows both stations to perform communication directly through this assigned communication modem (SCU). The assignment of the modem (SCU) is performed by sending messages to both base stations, and at this time, the corresponding area of the modem information storage unit 47 corresponding to the assigned communication modem is set to 1 so that the modem ( SCU) is referred to when assigning.

When the communication completion message is transmitted from the calling base station after the above-mentioned modem (SCU) allocation, the processor 41 transmits a message indicating that the communication is terminated for both base stations where the communication has been performed, and the modem information storage unit 47. The communication termination process is executed by setting the corresponding area of to 0 again.

However, in the above-described satellite communication system, the processor 41 checks the available modem (SCU) for every channel search based on a specific location specified, for example, the 'first address' of the memory map shown in FIG. Since each node is sequentially searched from the same point, there is a problem in that modem allocation is concentrated on a specific modem.

Accordingly, the present invention has been made in view of the above circumstances, and the subscriber can specify the location of the test modem according to the random number calculation result using the random function in searching for an IDLE modem required for communication. An object of the present invention is to provide a method and apparatus for retrieving an effective modem (SCU) of a satellite communication system that can be prevented from performing a modem search or a modem assignment due to a modem.

According to a first aspect of the present invention, a method for searching for an effective modem (SCU) of a satellite communication system according to the first aspect of the present invention may perform communication between arbitrary base stations by combining a plurality of base stations respectively coupled with a plurality of subscribers through satellites. In the satellite communication system, a random number generation step of generating random numbers through an irregular function calculation when a call request of an arbitrary base station occurs, and a test for calculating a predetermined value for selecting an effective modem test position based on the random number generated Positioning value calculation step, call availability check step for checking whether or not the communication modem corresponding to the calculated test location designation value, modem allocation step for allocating an effective modem (SCU) between both base stations according to the call availability Characterized in that configured to include.

In addition, an effective modem (SCU) search apparatus of a satellite communication system according to a second aspect of the present invention for realizing the above object is a satellite for providing a plurality of base stations, each of which is coupled with a plurality of subscribers, and a communication channel between each base station And a central control station for allocating and controlling a modem (SCU) usable for a base station having a call request, the central control station comprising: modem information storage means for storing a state of use of a communication modem; Random number generating means for generating a random number using a random function, Check position designation value calculating means for calculating a specified value for designating a corresponding test position for the modem information storage means based on the random number generated, and When there is a call request from any base station, a random number is generated through the random number generating means and the inspection position designation value calculating means is generated. On the basis of a result of the operation it is characterized in that is configured to include a control means for searching the communication modem (SCU) of the unused state for the modem information storage means.

That is, according to the present invention having the above-described configuration, in searching for an effective IDLE modem required for inter-subscriber communication, a specific modem (SCU) is designated by specifying the location of the test modem according to a random number calculation result using a random function. This can prevent the modem search from being performed or the modem assignment being made.

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 random number generator that generates random numbers through random function calculation according to a control command of the processor 60, which will be described later, and 80 denotes a random number generator 70. A check position designation value calculating section for calculating a designated value for designating a check position corresponding to the modem information storage section 47 based on a random number.

On the other hand, reference numeral 60 is a processor for executing a monitoring function of the communication modem, which is based on the calculation result of the check position designation value calculation unit 80 when there is a call request from any base station in the modem information storage unit 47; It is a processor that executes a call control function such as checking an unused communication modem and assigning it to a calling base station and a called base station so that both base stations can execute communication directly through the allocated communication modem.

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 random number generating unit 70 is controlled to generate a random number by calculating a random function (step ST5). Compute the check position designation value for the modem information storage unit 47 by using (ST6 step).

On the other hand, at this time, the calculation process of the inspection position designation value uses a method of dividing the generated random number by the number of available channels and taking the rest.

Subsequently, the processor 60 checks whether or not the modem of the modem information storage unit 47 can be used based on the result calculated by the above process (step ST7). If the status is available (ST8 step), the modem transmits a message to both base stations and allocates a modem (SCU) (ST9 step). Then, the corresponding address data of the modem information storage unit 47 is changed to '1' for call processing. (Step ST10)

That is, according to the above embodiment, modem search is performed by deciding a modem to locate a test modem according to a random number calculation result using a random function in searching for an IDLE modem necessary for communication between subscribers. Or modem assignments can be prevented.

Meanwhile, the present invention is not limited to the above embodiments and can be carried out in various modifications without departing from the technical rights of the present invention. For example, a modem search as described above may be performed as described above. It can be configured to execute repeatedly, or can be configured to follow the sequential modem search method again after irregular modem search.

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 abnormally operates in the second base station (NO.2 SET) among the N configured sub-base station modems (SCU) is identified, the processor (not shown) of the base station per row is determined by 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) when allocating the 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 .

As described above, according to the present invention, in searching for an effective IDLE modem necessary for inter-subscriber communication, the specific modem (SCU) is biased by specifying the location of the test modem according to a random number calculation result using a random function. It is possible to realize a method and apparatus for valid modem searching of a satellite communication system that can prevent modem searching or modem assignment from being performed.

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 through satellites to perform communication between arbitrary base stations, a random number that generates random numbers through an irregular function operation when a call request of any base station is required. A test location designation value calculating step of calculating a designation value for selecting an effective modem test location based on the generation step, the generated random number, and a call to confirm whether or not the modem corresponding to the calculated test location designation value can be used. And a modem allocation step of allocating an effective modem between both base stations according to whether or not a call is available. The method of claim 1, further comprising a normal modem checking step for screening a normal operation modem (SCU) first before executing the call availability checking 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 comprises: modem information storage means for storing a state of use of a modem (SCU), random number generating means for generating random numbers using a random function, and storing the modem information based on the generated random number An inspection position designation value calculating means for calculating a designation value for designating a corresponding inspection position for the means, and generating a random number through the random number generating means when there is a call request from an arbitrary base station; And control means for searching for the modem (SCU) in an unused state with respect to the modem information storage means based on the calculation result by the calculation means. Effective modem (SCU) search apparatus of the satellite communication system, characterized in that configured to. [4] The satellite communication system of claim 3, further comprising modem state storage means for storing operation state information indicating whether the modem is in normal operation in order to separately manage a normal operation modem (SCU). Modem Finder.