KR0183273B1 - Channel assignment method of satellite communication system - Google Patents

Abstract

According to the present invention, a communication system using satellites, especially when allocating two or more channels when a base station requires allocation of two or more channels, is used to manage management of a call channel by allocating two or more adjacent channels. The present invention relates to a channel allocation method and apparatus for a satellite communication system that facilitates the communication, and to 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 base station having a call request. A satellite communication system having a central control station for assigning and controlling an available communication channel of a satellite to a channel, comprising: channel information storage means for storing a state of use of a communication channel permitted by the satellite, and a first unused channel of the communication channel; First unused channel data storage means for storing data for End-use channel data storage means for storing data on the end-use channel of the call, and when there are two or more channel assignment requests from the base station, the end-use channel is called as the first unused channel when two or more consecutive channels do not exist. And a control means for controlling channel allocation by determining whether two or more consecutive channels are present after changing the channel.

Description

Channel allocation method and apparatus thereof 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 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 reference diagram for explaining a conventional channel allocation method.

6 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.

FIG. 7 is an operation flowchart for explaining the operation of the apparatus of FIG.

FIG. 8 is a reference diagram for explaining an embodiment of a channel allocation method in the apparatus of 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

50: network management system 60: processor

71: first unused channel data storage unit

72: last used channel data storage unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using satellites. In particular, when allocating two or more channels to a base station when allocating a transponder channel, the communication channel is managed by allocating two or more adjacent channels. The present invention relates to a channel allocation method and apparatus for a satellite communication system that facilitates the operation.

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, the PAMA (Pre Assignment Multiple Access) method of allocating communication channels for each subscriber according to the channel allocation method and the DAMA (Demand Assignment Multipul Access) method of allocating communication channels according to the 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 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 the polling function to check the available capacity or the communication channel. When there is a call request for a terminal of a specific base station, for example, the base station 3B, the mobile station determines whether the base station 3B can communicate with each other based on the information obtained during the polling process. In this case, 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 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) for separating and transmitting and receiving signals transmitted and received through 23, 23 is a low noise amplifier for low noise amplification of 12.25 ~ 12.75G 하향 downlink frequency signal inputted through the orthogonal mode converter 22 (LNA: 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 downshifter 24 into a plurality of intermediate frequency signals, and also describes a Single Channel Per Carrier (SCP) channel unit (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 IF signal of 70 MHz applied from the IF combination / distributor 25. For example, a frequency up-converter (UC: Up Converter) for converting the microwave into a microwave of 14.0 to 14.5G Hz to generate an uplink frequency signal, and 33 is a high output amplifier for amplifying the uplink frequency signal output from the frequency up-converter 32. (HPA: High Power Amplifier).

And, reference numeral 40 is a polling function for checking 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 that both base stations can directly communicate with each other by allocating the "

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 in the unit 26 to generate a S-ALOHA (Slootted ALOHA) packet, and a TDM (Time Division Multiplex) 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 that stores a state of use of a communication channel allowed by a 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, it generates a message of the TDM stream 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 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. .

On the other hand, the response message received by the antenna 21 from each base station 3 through the satellite 1, that is, the downlink frequency signal of 12.25 kHz is transmitted through the orthogonal mode changer 22 and the low noise amplifier 23. 24 is applied to the 70MHz intermediate frequency signal, 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 renewed and registered based on the packet data, thereby retaining status 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 when 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. In addition, the channel information storage unit 46 has a storage area corresponding to the number of communication channels allowable by satellites. Each storage area stores zero or one binary data depending on whether a corresponding communication channel is used. The binary data is changed 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 to allocate the communication channel. 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.

Next, a channel allocation method of the central control station 3 will be described with reference to FIG.

FIG. 5 is a diagram illustrating a channel allocation method of a conventional transponder channel in a mirrored method, in which (A) shows a general pattern of a franchise channel.

In the figure, TDM denotes a TDM channel, G denotes a guard band for protecting a traffic channel, S / A (Slotted Aloha) indicates a slotted Aloha channel, and 1 to 8 indicate respective traffic. Represents a channel.

In addition, in the transponder, the mirrored method uses the file of the middle boundary point (e.g., the boundary between channel 4 and 5) of two group channels because all traffic channels are logically divided into upper group channel and lower group channel. As shown in the mirror from the basis of the pilot sound, it functions as a transmission and a reception channel, respectively.

For example, when subscriber 'A' requests channel assignment of the transponder to communicate with subscriber 'A', as shown in FIG. 5 (B), subscriber 'A' is the first channel of the subgroup channel as a transmission channel. If the 'A' subscriber is assigned, the last channel of the upper group channel is allocated as the transmission channel corresponding to the 'A' subscriber.

At this time, the reception channel used by subscriber A uses the band of the transmission channel used by subscriber A ', and the transmission channel used by subscriber A' is used as a reception channel for subscriber A '.

Subsequently, if subscriber A and A 'are communicating, another subscriber' B 'requests allocation of a communication channel with' B ', as shown in (C) of FIG. 5, channels 2 and 7, 3 Channels 6 and 6 will exist as the active channel.

If the channel is allocated and then the 'A' subscriber and the 'A' subscriber release the call and are allocated the channel again, as shown in (D), the first channel and the last channel of the upper and lower group channels are not in use. Will remain.

At this time, if subscriber C requests allocation of two channels for a large amount of data communication such as data communication, the subscriber C does not need to allocate channel because there are no two consecutive channels required by subscriber C as described above. You cannot receive it.

Accordingly, the present invention has been made in view of the above circumstances, and when the base station requests the allocation of two or more channels when allocating a transponder channel, the first unused channel and the last used channel are determined. It is an object of the present invention to provide a channel allocation method and apparatus for a satellite communication system that facilitates management of a call channel by allocating two or more adjacent channels by searching.

The channel allocation method of the satellite communication system according to the first aspect of the present invention for realizing the above object is a satellite communication that can perform communication between any base station by combining a plurality of base stations, each of which is combined with a plurality of subscribers via satellite In the system, if any base station requests the allocation of two or more channels, a channel data retrieval step of retrieving active and non-use channels and storing the channel data, and whether two or more consecutive channels exist. Unused continuous channel search step to determine, if there are no two or more consecutive channels exist Unused channel search step to determine whether there are two or more channels separately, then two or more channels exist in the end-use channel Call channel change step, which changes the call channel to the first unused channel, the call channel is changed If after a judgment by the presence of at least two consecutive channel whether a two or more channels that are continuously re-present is characterized in that is configured to include a channel allocation method comprising: allocating at least two channels to the base station.

In addition, the channel allocation apparatus of the satellite communication system according to the second aspect of the present invention is a satellite for each base station that is combined with a plurality of subscribers, a satellite for providing a call channel between each base station, and the base station with a call request A satellite communication system having a central control station for assigning and controlling an available communication channel, comprising: channel information storage means for storing a state of use of a communication channel permitted by a satellite, and data for the first unused channel of the communication channel; Means for storing the first unused channel data for storing data, means for storing the last used channel data for storing the last used channel of the communication channel, and two or more consecutive channels if there is a request for allocation of two or more channels from the base station. If it does not exist, change the channel from the last used channel to the first non-used channel and change the channel again. It characterized in that it comprises a control means for controlling the channel assignment by determining the presence of two or more consecutive channels.

According to the present invention having the above-described configuration, in retrieving a channel available for channel allocation necessary for communication between subscribers, the subscriber requests two channels by storing information on channels that are already in use and channels that are not in use. In this case, the continuous channel is automatically generated to improve the reliability of the communication.

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

FIG. 6 is a block diagram for explaining a channel allocation method and apparatus for a satellite communication system according to an embodiment of the present invention. In FIG. 6, parts having substantially the same functions as those of FIG. The detailed description is omitted.

In the drawing, reference numeral 71 denotes the first unused channel data storage for storing information about the channel of the lowest band among the unused channels in the transponder channel as the processor 60 searches the channel information storage unit 46, which will be described later. And reference numeral 72 denotes an end-use channel data storage unit for storing information on the channel of the highest band among the channels being used in the transponder channel.

On the other hand, reference numeral 60 denotes a processor that executes a monitoring function of a communication channel, which is a function of the processor 41 described in FIG. 3, that is, when there is a call request from any base station, the channel information storage unit 46 is unused. It checks the communication channel and assigns it to the calling base station and the called base station so that both base stations can execute the communication directly through the assigned communication channel. By storing information about unused channels, the processor controls allocation of consecutive channels when the subscriber requests allocation of two or more channels.

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. 6, when a call request message from an arbitrary base station is input to the processor 60 through the service channel controller 42 (step ST701), 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 to determine whether the base station is in a state where a current call is possible (step ST702).

When the base station called in step ST702 is determined to be in a callable state, the processor 60 checks the communication channel of the channel information storage unit 46 and allocates them to the calling base station and the called base station, thereby allocating the base stations. When the base station requests the allocation of two or more channels for a large amount of data communication (ST703), the processor 60 performs the channel information storage unit. The channel data of 46) is read out to search for the highest-band transponder channel (last used channel) and the lowest-band unused transponder channel (first unused channel) (step ST704).

Then, the processor 60 stores the last used channel data of the franchisor channel according to the search result in the last used channel data storage 72, and stores the first unused channel data in the first unused channel. The data storage unit 71 stores the data in the data storage unit 71 (step ST705).

Thereafter, the processor 60 determines whether there are two or more consecutive channels among the transponder channels (step ST706), and if two or more consecutive channels exist, the processor 60 assigns them to the corresponding base station 2 (ST707). ).

However, if two or more consecutive channels of the transponder channel do not exist, the processor 60 then determines whether two or more channels are not in use but are not in use (step ST708). If more than one continuous channel does not exist and two or more channels do not exist individually, the processor 60 cannot assign a channel to the subscriber's allocation request of two or more channels. Data communication using the above channel cannot be performed (step ST709).

On the other hand, if there are two or more non-contiguous channels in step ST708, the processor 60 stores the data of the first unused channel data storage 71 in the last used channel data storage 72. In addition to updating and storing as channel data, as shown in (B) of FIG. 9, a call channel is changed for a channel corresponding to the channel data stored in the end-use channel data storage unit 72, and a call is made to the base station. The channel is requested to be changed (step ST710 and ST711).

Subsequently, the processor 60 executes the change of the call channel and then searches the channel information storage unit 46 again to determine whether two or more consecutive channels exist. (Step ST712, ST713). Thus, when there are two or more consecutive channels as shown in a of FIG. 8 (B), channel allocation is terminated by allocating two or more channels required by the base station (step ST714).

On the other hand, if two or more consecutive channels do not exist in step ST713, the process proceeds to step ST710 to re-execute the above operation.

In addition, the change of the call channel of the upper group channel is the same as the change of the call channel of the lower group channel.

That is, according to the above embodiment, when the subscriber searches for a channel available for channel allocation necessary for communication, the subscriber requests two or more channels by storing information on channels that are already in use and channels that are not in use. In this case, successive channels are automatically generated to improve the reliability of communication.

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 allocating two or more channels when the base station requests the allocation of two or more channels, the management of the communication channel can be facilitated by allocating two or more adjacent channels. It is possible to realize a channel allocation method and apparatus for a satellite communication system that enables the communication.

Claims (5)

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 satellites to perform communication between arbitrary base stations, when an arbitrary base station requires allocation of two or more channels, it is in use and not in use. Channel data retrieval step of retrieving channels and storing this channel data, and unused continuous channel retrieval step of judging whether there are two or more consecutive channels, or separately if two or more consecutive channels are not present. Unused channel search step for determining whether more than one channel exists, if there are more than two channels, then change the call channel to change the call channel to the first unused channel for the last used channel, the call channel changed Afterwards, it is judged whether there are two or more consecutive channels. When the second channel allocation method of a satellite communication system, characterized in that configured with more than one channel comprises a channel allocation step of allocating to the base station. 2. The method of claim 1, wherein if there are two or more consecutive channels in the unused continuous channel search step, the process proceeds to a channel assignment step to allocate channels. The method of claim 1, wherein if two or more consecutive channels do not exist after the change of the call channel, the process returns to the change of the call channel and repeats the process. 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. A channel information storage means for storing a usage state of a communication channel allowed by a satellite, a first unused channel data storage means for storing data for a first unused channel of a communication channel, and a last used channel of a communication channel End-use channel data storage means for storing data for the data, if there is more than one channel allocation request from the base station, if there are no two or more consecutive channels, the last-use channel is changed to the first unused channel. After execution, it determines whether two or more consecutive channels exist and controls channel allocation. Channel allocation apparatus of a satellite communication system comprising a control means. 5. The method of claim 4, wherein the control means performs channel assignment after changing the last used channel to the first unused channel again when two or more consecutive channels do not exist after the change of the call channel. Channel allocation apparatus of a satellite communication system, characterized in that for controlling.