KR980013015A - 2 Channel Assignment Method Using Mirror Method of Satellite Communication System and Its Apparatus - Google Patents

Abstract

According to the present invention, in allocating a transmission (TX) channel and a reception (RX) channel for two-way voice communication, the channel is mirrored to the remaining channel band except for the channel to be used as a service channel. The present invention relates to a two-channel allocation method and a device using a mirrored method of a satellite communication system that simultaneously allocates two channels in a symmetrical position based on a center frequency by a pair. The channel pairs are formed by pairing two channels placed in symmetrical positions based on the center frequency using the mirror method for the remaining channel bands except for the service channel among the bands, and requesting a call of an arbitrary subscriber. Search the available channel pairs for the channel frequency information for each channel of the indexed effective channel pairs from the memory. And transmits the information panel on the basis of this assignment by the output yang station characterized in that the assignment to the transmission / reception channel.

Description

2 Channel Assignment Method Using Mirror Method of Satellite Communication System and Its Apparatus

The present invention relates to a satellite communication system. In particular, in allocating the TX and RX channels required for two-way voice communication, the mirrored method is used for the remaining channel bands except for the channel to be used as the service channel. The present invention relates to a two-channel allocation method and a device using a mirrored method of a satellite communication system which simultaneously allocates two channels in a symmetrical position with respect to a center frequency.

In general, voice communication using satellite refers to providing a two-way communication service so that voice calls can be made between two remote subscribers via a stationary satellite mounted at an altitude of 36007 km. FIG. Fig. 1 shows the overall system configuration of the Demand Assignment Multiple Access (DAMA) satellite communication system, which is configured to allocate a communication channel on demand.

In Fig. 1, reference numeral 1 is a satellite having a plurality of communication channels, 2 is a central control station for controlling the entire satellite communication system, and 3 (3A, 3B) is an exchanger (11A, 11B) or a telephone (12A, 12B). Interface between the terminals such as a computer, data terminals 13A and 13B, and facsimile units 14A and 14B, and data transmission and reception with the central control station 2 between the terminals. A base station that provides a call function.

In FIG. 1, reference numeral S denotes a service channel for transmitting and receiving control data. T represents a traffic channel for transmitting and receiving data or voice.

In the above configuration, the central control station (2) periodically transmits a control message through a TIA (Tiae Division Multiplex) type of service channel, and is then transmitted from the base station 3 in a slotted aloha (S / A) manner. On the basis of the analysis of the incoming and outgoing message, a polling function is performed to determine the state of each base station 3, that is, the available capacity of the communication capacity or the communication channel. When there is a call request from a specific base station, for example, the base station 3A to the terminal of the base station 3B, it is determined whether the corresponding base station 3B is in a state in which communication is possible based on the information obtained in the polling process. In the case of the communicable state, the available traffic channel T of the satellite is allocated to both base stations 3A and 3B so that both base stations 3A and 3B can directly communicate with each other.

Thereafter, the central control station 2 transmits to both base stations when the communication end signal is applied through the service channel S from the base station 3A where the communication request is completed and the communication ends between the base stations 3A and 3B. By executing the communication termination process for the base station, the traffic channel T which has been provided to both base stations 3A and 3B is released.

On the other hand, the number of radio resources that can be provided by the satellite system, that is, the communication channel is related to the specifications of the satellite transponder mounted on the satellite 1, Figure 2 is a communication channel provided by the satellite repeater In the following description, a channel division state of a satellite repeater (transponder) having a bandwidth of 36 MHz is illustrated.

The channel allocation illustrated in FIG. 2 is a case where TDM channels and S / A channels are used one by one and each is allocated to both edge portions of an available frequency band. The control data transmitted from the central control station 2 to the base station 3 is transmitted in a TDM method having a frequency band of 83.2 KHz, while the control transmitted from the base station 3 to the central control station 2 is transmitted. Data is transmitted by S / A method having a frequency band of 41.6KHz. Accordingly, in consideration of this, as shown in FIG. 2, three channels (90 KHz) among 1200 communication channels divided in units of 30 KHz are TDM service channels (S), and at least two channels (60 KHz) are S /. Each of them is fixedly assigned as the service channel S of the A method, and the rest of them are used as the traffic channel T.

On the other hand, two-way voice communication requires two channels, a transmission channel TX and a reception channel RX, and the central control station 7 receives a call request from any subscriber. It is necessary to select two channels efficiently and allocate them as a transmission channel TX and a reception channel RX for communication between two subscribers.

The present invention has been made in view of the above circumstances, and in allocating a transmission (TX) channel and a reception (RX) channel required for bidirectional voice communication (trffic), except for a channel to be used as a service channel among all frequency bands. Allocated in pairs to two channels in a symmetrical position based on the center frequency set by dividing the entire frequency band in half, such as a mirrored method for the channel band, that is, a symmetrical shape reflected through the mirror surface. It is an object of the present invention to provide a two-channel allocation crime prevention and a device using a mirrored method of the satellite communication system.

The two-channel allocation method using the mirrored method of the satellite communication system according to the first aspect of the present invention for realizing the above object by canceling a plurality of base stations coupled with a plurality of subscribers via satellite In satellite satellite system that can communicate with each other, two channels placed at symmetrical positions with respect to the center frequency divided by two of the remaining channel bands except the channel to be used as a service channel among all available frequency bands of the satellite are matched. A channel pair forming step for forming a channel, an effective channel color search step for searching an effective channel pair usable for a call request of an arbitrary subscriber, and channel frequency information for each channel of the effective channel pair indexed in this effective channel search step Read step of reading channel frequency information from memory and assign it based on read channel frequency information And transmitting the channel information in both the base station is characterized in that is configured including a channel RANDAN assigning a transmit / receive channel.

In addition, the two-channel allocation apparatus using a mirrored method of the satellite communication system according to the second aspect of the present invention is a satellite for providing a communication channel between a plurality of base stations and each base station, each coupled with a plurality of subscribers And a central control station for allocating and controlling a call channel usable for a base station with a call request, wherein the central control station controls the whole system, and in particular, control means for controlling call processing between base stations. And base station information storage means for storing state information of each base station obtained by the polling operation of the control means, based on the two-division center frequency of the remaining channel bands except for channels to be used as service channels among all available frequency bands of the satellite. Channels that store the utilization status of this paired channel pair by pairing two channels in symmetrical positions Storage means, and channel frequency information storage means for storing, as data, frequency information for two channels corresponding to each address of the channel information storage means, wherein the control means has a call request from any base station subscriber. If so, the effective channel pair is searched based on the data stored in the base station information storage means and the channel information storage means, and the channel allocation is controlled according to the channel information of the found effective channel.

That is, according to the present invention having the above-described configuration, in assigning a transmission (TX) channel and a reception (RX) channel required for two-way voice communication, the mirrored method is used based on the center frequency. By simultaneously assigning two channels in symmetrical positions in pairs, the channel assignments can be made faster, without the hassle of assigning separate transmit / receive channels twice.

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

3 is a configuration diagram showing the configuration of the central control station 2 that executes the above-described transmission / reception channel allocation function.

In FIG. 3, reference numeral 21 denotes an antenna for transmitting and receiving downlink signals transmitted from the satellite side as opposed to an uplink signal transmitted to the satellite 1 side, and 22 using a polarization property of frequency. Orthogonal Mode Transducer (OMT) 23 for disadvantageously inputting and outputting signals transmitted and received through the Andena 22, for example, 12.25 to 12.75 GHz downlink frequency inputted through the Orthogonal Mode Transducer 22 Low Noise Amplifier (LNA) for low noise amplifying the signal, 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. Down Converter).

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 / distribution unit 25 is employed for system scalability when using a plurality and an SCPC channel unit.

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 microwaves into microwaves of 14.0 to 14.5 GHz to generate an uplink frequency signal. HPA: High Power Amplifier.

Reference numeral 40 denotes a polling function that checks 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 there is a call request from a specific base station, it is determined whether the other base station is in a communication state based on the information obtained in 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.

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 4 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 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

Further, reference numeral 43 is 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 41, 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 control unit 40. Is a channel information storage unit that stores a state of use of a communication channel allowed by a satellite.

5 is a diagram illustrating memory mapping of the channel information storage unit 46. The channel information storage unit 46 is an acceptable communication channel to be determined by the specifications of a transponder mounted on a satellite. Each storage area has a storage area equal to 1/2 the number of traffic channels, and each storage area has a value of "0" or "1" depending on whether two communication channels (TX, RX) are addressed to the corresponding address. Binary data will be stored. And. The binary data is changed by the processor 41 according to the use state of the communication channel.

Meanwhile, as shown in FIG. 5, the channel information storage unit 46 allocates the transmit / receive channel as a pair so that two channels except for the service channel of the 1200 channels are paired. Thus, a storage area of 594 addresses is provided.

In FIG. 4, reference numeral 48 denotes a channel frequency information storage unit for storing channel frequency information corresponding to each address of the channel information storage unit 46 as data. The channel information storage unit 46 is searched by an effective channel search. If any one of 594 addresses is designated as an allocation channel, it is to provide channel frequency information for each channel for a two-channel paired pair in a mirrored manner. That is, when an address for a pair of channels available by valid channel pair search is specified, 2 having the same predetermined frequency interval based on the center frequency divided by two of the remaining channel bands except the channel to be used as a service channel among all frequency bands Channels are automatically calculated.

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

Normally, the network controller 40 of FIG. 3 periodically performs a fling operation to check the state of each base station.

In other words, 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. The service channel loan lor 42 reads the whetkit data written in the dual port RAM 43, generates a message of the TD ler stream, and outputs the message to the SCPC channel unit 31.

However, the SCPC channel unit 31 converts the message into an intermediate frequency signal of 70 kHz, for example, and outputs the encoded and modulated message. This intermediate main fruit signal is combined for each frequency in the IF combination / distributor 25, and then converted into an uplink frequency signal of, for example, 14. SGH7 in the frequency increase conversion factor 32. Then, the uplink frequency signal is outputted through the high output heavy amplifier 33, the zigzag mode converter 22, and the antenna 21, and transmitted to each base station through the phosphor satellite 1 in FIG. Become

On the other hand, the unanswered message received by the antenna 21 from each base station 3 through the satellite 1, that is, the downlink frequency signal of 12.250Hz is frequency down via the orthogonal mode converter 22 and the low noise amplifier 23. It is applied to the converter 24 is converted into an intermediate frequency signal of 70MHz, 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. .

In addition, the network controller 40 extracts packet information from the message applied by the service channel controller 42 to generate an S-ALOHA packet, and then writes the packet to the dual port RA7 43. By reading the corresponding packet data from the port RA Lee 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 performed fairly continuously for each base station.

The transmission / reception channel allocation operation proceeds afterwards is described in more detail by creating a flowchart of FIG. 6.

If there is a calling request from any base station to any other base station during the above-mentioned polling operation, that is, a message indicating a call request from the satellite 1 is received through the antenna 21 of FIG. When the corresponding packet data is input from the service channel switching controller 42 of the controller 40, the processor 41 first checks this and then checks the state information of the base station called by the base station information storage unit 45. It reads (572) it is determined whether the base station is currently in a state capable of communication (573), and if the called base station side is in a communication impossible state for reasons such as busy, the processor 41 is a call to the call base station side. 7 Tin 574 that sent the message. The channel assignment operation is terminated, and when it is determined that the communication is possible, the channel information storage 47 is searched to find a usable communication channel.

At this time, the processor 41 checks whether the channel pair of the corresponding address is in use from the start address of the channel information storage unit 47 (576), in which the channel pair of the corresponding address is in use ('1'). If it turns out to be, it repeats the above checking operation until an example of a valid channel pair is confirmed by increasing the address '1' section into the brain where no channel is available. (577)

When the channel pair having a channel state of '7' is identified, the processor 41 determines two channels of the channel pair from the channel frequency information storage unit 48 based on the address data of the channel pair identified as the effective channel. By reading the frequency jumbo (577), and sending it to both sides known and assigned to the two-way voice call transmission / reception channel is allocated. (579)

As a result. As shown in FIG. 7, even when up to four S / A channels are accommodated, the transmission and reception channels are allocated with the optimized optimized state remaining as an empty channel.

Subsequently, the processor 41 changes the corresponding address data of the channel information storage ◎ 46 to '1' and sets it to 5711. Then, when the message indicating that the call is terminated is received from the call base station, it is checked ( 5711) By changing the corresponding address data of the channel information storage unit 4 to '7', the channel allocation for the call request and the overall channel residual operation rate are terminated.

That is, according to the above embodiment, in allocating a transmission (Tx) channel and a reception (nx) channel required for bidirectional voice communication (trarric), a mirrored (airrored) method is used in a symmetrical position with respect to the center frequency. By allocating two channels simultaneously in pairs, you can eliminate the hassle of allocating the send / receive channels separately at the same time and make faster channel assignments.

In addition, the transmission (TX) channel and the reception (RX) channel are managed in column pairs, so that the memory used for channel management, that is, the area used for the channel information storage port 47, can be reduced by half. Loaning of specific full bandwidth is facilitated by sequentially assigning channels without converting them.

On the other hand, the present invention is not limited to the above embodiments and can be practiced in various modifications within the scope not departing from the technical rights of the year.

1 is an overall system configuration for explaining the outline of a general satellite communication system,

2 is a diagram illustrating a channel division state of a satellite transponder mounted in the satellite 1 shown in FIG. 1;

3 is a block diagram showing in detail the configuration of the central control station 2 according to the present invention;

4 is a block diagram showing the configuration of the network control unit 40 in the satellite communication system according to an embodiment of the present invention;

5 is a memory map diagram of the channel information storage section 46 shown in FIG.

6 is a flowchart illustrating a channel assignment process of the device of FIG.

7 is a diagram illustrating a state in which a communication channel is allocated by a channel allocation method according to the present invention.

* Explanation of symbols for the 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: Acymil, 21: Antenna,

22: quadrature mode converter, 23: low noise amplifier,

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

26, 31: SCPC channel unit, 32: frequency up converter,

33: high output heavy amplifier, 40: network control unit,

41: processor, 42: service channel launch handler,

43: dual port RAM, 44: program storage.

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

4e: channel frequency information storage unit, 50: network management system

Claims (2)

A satellite communication system in which a plurality of base stations, each of which is combined with a plurality of subscribers, can be combined via satellite to perform communication between arbitrary base stations. Channel pair forming step of forming channel pairs by pairing two channels placed in symmetrical positions with respect to two divided center frequencies of the remaining channel bands except for the channel to be used as a service channel among all available frequency bands of the satellite; A valid channel pair retrieval step of retrieving an effective channel pair usable for a call request of a channel frequency reading step of reading channel frequency information for each channel of the effective channel pair indexed in this effective channel retrieval step from a memory; And a channel assignment step of allocating channel information allocated to the base stations based on the read channel frequency information and allocating a transmission / reception channel. In 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 communication channel between each base station, and a central control station for allocating and controlling a usable communication channel for a base station having a call request. The central control station controls the entire system, and in particular, control means for controlling call processing between base stations, base station information storage means for storing status information of each base station obtained by the polling operation of the control means, Save channel information to save the utilization status of the paired channel pairs by pairing two channels placed in symmetrical positions based on the center frequency divided by two except for the channel to be used as service channel among all available frequency bands. Means and frequency information for two channels that are treated at each address of the channel information storage means. And a channel frequency information storage means for storing the data, and the control means searches for an effective channel on the basis of the data stored in the base station information storage means and the channel information storage means when a call request is received from an arbitrary base station subscriber. 2. A channel allocation apparatus using a mirrored method of a satellite communication system, characterized in that channel allocation is controlled according to channel information of an effective channel. ※ Note: The disclosure is based on the initial application.