KR0183276B1 - Effective channel searching method of satellite communication system - Google Patents

Abstract

According to the present invention, in a satellite communication system, when searching for an IDLE channel required for inter-subscriber communication, the channel state data is first bundled by a predetermined number of units to determine whether there is an effective channel therein, and then the result is determined. Accordingly, the present invention relates to a method and apparatus for searching for an effective channel of a satellite communication system, which enables a user to perform various effective channel searches more quickly by checking whether each channel can be used in detail. The central control station is a communication channel allowed by a satellite. Comparing channel information storage means for storing the state of use with the latch temporarily storing the read channel state data, and whether the data temporarily registered in the latch is the first level and outputting a predetermined determination signal according to the result. Effectiveness for each channel according to the comparison determination means and the level of the signal output from the comparison determination means And control means for controlling to search for a channel.

Description

Effective channel search method and system for 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 in FIG.

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

4 is a memory map diagram of the channel information storage unit 46 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 illustrating an effective channel search and channel allocation operation of a satellite communication system according to the present invention.

* 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

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 effective channel for communication between subscribers, first, by checking channel status data by a predetermined number unit and checking whether there is an effective channel therein, The present invention relates to a method and apparatus for searching for an effective channel of a satellite communication system that enables effective channel searching to be performed more quickly by checking whether or not each channel can be used in detail according to the result.

Recently, with the rapid development of communication technology, satellite communication, which enables subscribers who are located at remote sites to make calls through satellites, has become increasingly common. Since such satellite communication does not require a separate signal line for a call, It is mainly used as a long distance communication between countries or as a communication method in a mountainous country such as Korea.

In the above-mentioned satellite communication, 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 Multikful Access (DAMA) 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 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). 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. 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 satellite can allocate the available traffic channel T 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 denotes an antenna for transmitting / receiving an satellite 1, an uplink signal, and a downlink signal, and 22 denotes an antenna 22 using frequency polarization characteristics. Orthogonal Mode Transducer (OMT) 23 for separating and inputting / receiving signals transmitted / received through a low noise amplifier for low noise amplification 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. SCU: an intermediate frequency combiner / distributor (IF C / D: IF combiner / distributer) which combines and outputs an intermediate frequency signal applied from 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.

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. If a call is requested from a specific base station, the base station determines whether the other base station can communicate with each other based on the information obtained during the polling process. It is a network control unit that performs system control such as assigning T) to both base stations so that both base stations can directly communicate with each other.

Also, reference numeral 50 denotes a network management system for managing the overall network of the satellite communication system by the system manager managing the network control unit 40.

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 A packet information is extracted from a message authorized by the unit 26 to generate a slotted packet (S-ALOHA), 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, 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; 46 is a channel information storage unit for storing the use state of the communication channel allowed by the satellite.

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 quadrature 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, it is determined whether or not the communication state is possible, and if it is determined that the communication is possible, the communication channel currently available from the channel information storage unit 46 is examined.

4 is a diagram illustrating memory mapping of the channel information storage unit 46. The channel information storage unit 46 has a storage area corresponding to the number of communication channels allowable by satellites, and stores each of them. In the area, binary data of 0 or 1 is stored depending on whether a corresponding communication channel is used. The binary data is changed and set by the processor 41 according to the use state of the communication channel.

That is, when there is a call request from any base station, when the busy state of the communication channel is 1, the processor 41 checks the communication channel written with 0 in the channel information storage unit 46 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 channel. The communication channel is allocated by sending messages to both base stations, and at this time, the corresponding area of the channel information storage unit 46 corresponding to the allocated communication channel is set to 1 so that the subsequent communication channel is allocated. Will be referenced.

When the communication end message is transmitted from the calling base station after allocating the communication channel, the processor 41 transmits a message indicating that the communication is terminated to both base stations where the communication has been performed, and the channel information storage unit 46 transmits a message. The communication end process is executed by setting the area to 0 again.

However, in the above-described satellite communication system, the processor 41 checks whether the available channel can be used for each channel based on a specifically designated position such as 'first address' of the memory map shown in FIG. Because it is to confirm, there was an inefficient disadvantage in searching the effective channel.

Accordingly, the present invention was created in view of the above circumstances, and in searching for an effective channel required for inter-subscriber communication, first grouping channel state data by a predetermined number unit and checking whether there is an effective channel therein. It is an object of the present invention to provide a method and apparatus for searching for an effective channel of a satellite communication system that can perform effective channel searching faster by checking whether or not each channel can be used in detail according to the result.

The effective channel search method of the satellite communication system according to the first aspect of the present invention for realizing the above object is to combine a plurality of base stations coupled with a plurality of subscribers via satellite to perform communication between any base station In the satellite communication system, a channel state information latching step of reading and latching channel state information of a predetermined byte unit at a time when there is a call request of an arbitrary base station, and comparing and determining whether the latched channel state data is all '1' Comparing and determining the effective channel for each channel according to the comparison determination step, according to the result of the determination, characterized in that it comprises a configuration.

In addition, the effective channel search apparatus of the satellite communication system according to the second aspect of the present invention for realizing the above object is 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 allocating and controlling an available communication channel of a satellite to a base station on demand, wherein the central control station stores channel information storing a state of use of a communication channel allowed by the satellite. And comparison latch means for temporarily storing the read channel state data, comparing and determining whether or not the data temporarily registered in the latch are all at the first level, and outputting a predetermined determination signal according to the result. And control means for controlling to search for the effective channel for each channel according to the level of the output signal. Characterized in that a.

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

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

FIG. 5 is a block diagram showing an effective channel search 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 channel state data in unit of 1 byte read out from the channel information storage unit 46 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 latch 70 are all '1', and according to the result of the determination, for example, if all are '1', a high level judgment signal is selected, and if any one is '0', a low level judgment is made. It is a comparison judgment outputting signal.

On the other hand, reference numeral 60 is a processor for executing a monitoring function of the communication channel, which reads the channel state data in units of 1 byte from the channel information storage unit 46 when there is a call request from any base station, and the latch 70. After a temporary registration, the processor performs a normal effective channel search for each channel according to the level value of the determination signal applied from the comparison determination 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 channel state data in one byte unit is read from the channel information storage unit 46 and temporarily stored in the latch 70. (Step ST5), the comparison judgment unit 80 compares and determines whether all 8 bits are '1' (step ST6).

If it is confirmed that all of the comparison results are '1' (step ST7), since there is no available channel, the above checking operation is repeated until the valid channel is confirmed within the byte unit by increasing the address by 1 byte. In step ST8, the processor 60 executes a channel search for each bit (channel) only when it is confirmed that the channel state is not all '1'.

When the available channel is found as a result of the search (step ST10), the processor 60 transmits a message to both base stations and allocates a call channel (step ST11). Then, the corresponding address data of the channel information storage unit 46 is' By changing to 1 ', call request processing is terminated. (ST13 step)

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

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 channel required for inter-subscriber communication, first, the channel state data is bundled in a predetermined number unit, and whether or not there is an effective channel therein is determined in detail. By checking the availability of each channel, the effective channel search method and apparatus of the satellite communication system, which can perform the effective channel search more quickly, can be realized.

Claims (2)

In a satellite communication system in which a plurality of base stations, each of which is combined with a plurality of subscribers, are combined through satellite to perform communication between arbitrary base stations, when a call request of a certain base station is required, channel state information of a predetermined byte unit is read out at a time. And latching the channel state information latching step, and comparing and determining whether the latched channel state data is all '1', and checking whether or not the effective channel is valid for each channel according to the comparison determination result. Effective channel search method of a satellite communication system, characterized in that configured to. A satellite communication system having a plurality of base stations, each of which is combined 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 the available call channels of the satellites to the base stations with call request. The central control station comprises: channel information storage means for storing a state of use of a communication channel permitted by the satellite, a latch for temporarily storing the read channel state data, and data temporarily registered in the latch are all at a first level. A comparison judging means for judging the recognition and outputting a predetermined judging signal according to the result, and control means for controlling the retrieval of the effective channel for each channel according to the level of the signal output from the judging means. An effective channel search apparatus for a satellite communication system.