KR100205642B1 - Tranmitting and receiving channel assigning method in satellite telecommunication system - Google Patents

Abstract

The present invention provides two subscriber stations by sequentially assigning two available channels identified by the effective channel search to the transmission (TX) channel and the reception (RX) channel required for two-way voice communication for the subscriber's call request. The present invention relates to a method for allocating a transmit / receive channel for two-way voice communication of a satellite communication system configured to provide a communication path between two or more base stations. A satellite channel communication system comprising: an effective channel search step of searching for an available channel available for a call request of an arbitrary subscriber; and assigning an effective channel indexed in this effective channel search step as a first channel for two-way voice communication; A first channel assignment step, a channel assignment status confirmation step of confirming whether the first channel is in an assigned state, the channel assignment A second channel search step of searching for an effective channel for the second channel assignment when the first channel is identified as allocated in the status checking step, and a second channel for bidirectional communication using the effective channel indexed in the second channel search step And a channel assignment step of allocating a second channel assignment step of allocating channels to the base station and transmitting channel information assigned to the first and second channels to both base stations.

Description

Transmission / reception channel allocation method for two-way voice communication of satellite communication system

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.

3 is a block diagram showing details of the configuration of the central control station 2 shown in FIG.

4 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.

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

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

48: transmitting channel allocation information storage unit 49: receiving channel allocation information storage unit

50: network management system

The present invention relates to a satellite communication system. In particular, two available channels identified by the effective channel search for a subscriber's call request are required for a transmission (TX) channel and a reception (RX) for two-way voice communication. The present invention relates to a transmission / reception channel allocation method for two-way voice communication of a satellite communication system that provides a communication path between two subscribers by sequentially assigning channels.

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 through a stationary satellite mounted at an altitude of 36000 km. 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). Communication function between terminals such as a computer, data terminals 13A and 13B, and facsimile 14A and 14B, and data transmission / reception with the central control station 2 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 periodically transmits a control message through a time division multiplex (TDM) type service channel, and is then transmitted from the base station 3 in a slotted aloha (S / A) type. Based on the analysis of the response message, the polling function is performed to check the state of each base station 3, that is, the available capacity of the communication channel 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. When the communication state is available, the available traffic channels T of the satellites are allocated to both base stations 3A and 3B so that the base stations 3A and 3B can directly communicate with each other.

Then, the central control station (2) is terminated between the two base stations (3A, 3B) when the communication end signal is applied through the service channel (S) from the base station (3A) communication request was requested for 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.

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

The channel state illustrated in FIG. 2 is a case where each of the TDM channel and the S / A channel is accommodated and assigned to each of the available frequency bands. 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 control data transmitted from the base station 3 side to the central control station 2. Is transmitted in an S / A method having a frequency band of 41.6 KHz. Therefore, in consideration of this, as shown in FIG. 2, three channels (90 KHz) among 1200 communication channels divided by 30 KHz units are TDM service channels (S), and at least two channels (60 KHz) are S /. The service channel S of the A method is fixedly assigned to each other, and the rest of the service channel S is 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 2 receives a call request from a certain subscriber. It is necessary to efficiently select two channels and allocate them as a transmission channel TX and a reception channel RX required for communication between two subscribers.

The present invention has been made in view of the above circumstances, and the two available channels identified by the effective channel search for the subscriber's call request are required for the transmission (TX) channel and the reception (Tx) required for two-way voice communication. The purpose of the present invention is to provide a transmission / reception channel allocation method for two-way voice communication of a satellite communication system that provides a communication path between two subscribers by sequentially assigning each channel to an RX) channel.

In order to achieve the above object, a method for allocating a transmission / reception channel for two-way voice communication in a satellite communication system according to the present invention can perform communication between arbitrary base stations by combining a plurality of base stations respectively coupled with a plurality of subscribers through satellites. A satellite channel communication system comprising: an effective channel search step of searching for an available channel available for a call request of an arbitrary subscriber; and assigning an effective channel indexed in this effective channel search step as a first channel for two-way voice communication; A first channel assignment step, a channel assignment status checking step of confirming whether the first channel is allocated, and the channel assignment status checking step is valid for a second channel assignment when it is determined that the first channel is assigned. A second channel search step of searching for channels, and the effective channel indexed in the two channel search step is now a second channel for bidirectional communication. And transmitting the determined second channel assignment phase, and the first, the channel information assigned to the second channel by both base stations characterized in that configured to include a channel allocation step of allocating the transmit / receive channel.

That is, according to the present invention having the above-described configuration, a transmission (TX) channel and a reception (RX), which are required for two-way voice communication, are used for two available channels identified by the effective channel search for the subscriber's call request. By sequentially assigning each channel, the available radio resources can be optimized and used.

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 denotes a polarization characteristic of frequency. Orthogonal Mode Transducer (OMT) 23, which separates and transmits and receives signals transmitted and received through the antenna 22 by using the downlink frequency of 12.25 to 12.75 GHz, for example, inputted through the Orthogonal Mode Transducer 22 Low Noise Amplifier (LNA) for low noise amplification, 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. )to be.

In addition, the reference numeral 25 separates and outputs the intermediate frequency signal IF applied from the frequency down converter 24 into a plurality of intermediate frequency signals, and also describes a Single Channel Per Carrier (SCP) channel unit to be described later ( SCU: an intermediate frequency combiner / distributor (IF C / D: IF combiner / distributer) 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 upconverter (UC) for converting into microwaves of 14.0 to 14.5 GHz to generate an uplink frequency signal, 33 is a high power amplifier (HPA) for amplifying an uplink frequency signal output from the frequency upconverter 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, it is determined whether the other base station can communicate with each other based on the information obtained in the polling process. ) Is a network control unit that performs system control such that both base stations 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 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 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

In addition, reference numeral 43 is a dual port RAM, and 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.

5 is a diagram illustrating memory mapping of the channel information storage unit 46. The channel information storage unit 46 is an allowable communication channel to be determined by the specifications of a transponder mounted on a satellite. In consideration of the number of s, the storage area corresponding to the storage area has a corresponding storage area and binary data of "0" or "1" is stored in each storage area depending on whether a communication channel corresponding to the corresponding address is used. The binary data is changed and set 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 has a storage area corresponding to 1200 channels. Among them, three channels assigned to the TDM channel and two channels assigned to the S / A channel are provided. For each of the four channels, the processor 41 always adjusts the data of the corresponding address to " 1 " so as not to be allocated to the traffic channel T.

That is, when there is a call request from any base station, the processor 41 examines the communication channel written as "0" in the channel information storage unit 46 when the busy state of the communication channel is "1". By allocating for the calling base station and the called base station, it is possible for both base stations to perform communication indirectly through this allocated communication channel. This 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 " Reference is made during allocation.

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 termination process is executed by setting the corresponding area to '0' again.

On the other hand, reference numeral 48 is a transmission channel assignment information storage unit for storing the channel information of the first identified effective channel to be allocated to the transmission channel under the control of the processor 41, 49 is the two to be assigned to the receiving channel A receiving channel assignment information storage unit for storing the channel information of the second effective channel.

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. 3 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. It is applied to (24) is converted into an intermediate frequency signal of 70MHz, and then applied to the SCPC channel unit 26 through the IF combination / distribution unit 25, demodulated and decoded and then applied to the network controller 40.

In addition, the network controller 40 extracts the packet information from the message to which the service channel controller 42 is applied, generates an S-ALOHA packet, and writes it to the dual port RAM 43, and the processor 41 generates a dual packet. By reading the packet data from the port RAM 43 and updating and registering the base station information storage unit 45 based on this, the state information for each base station is retained.

In addition, the above-described polling operation is continuously performed for each base station.

Hereinafter, the transmission / reception channel allocation operation proceeds in more detail with reference to the flowchart of FIG. 5.

When 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 corresponding packet data is input from the service channel controller 42 of 40, the processor 41 first checks this (ST1), and then reads the state information of the called base station from the base station information storage unit 45 (ST2). The base station determines whether or not the current communication is possible (ST3), and if the called base station side is in a state where communication is not possible due to a busy call, etc., the processor 41 sends a call impossible message to the call base station side ( ST4), the channel assignment operation is terminated, and if it is determined that the communication is possible, the channel information storage unit 46 is searched to find a currently available communication channel. (ST5)

At this time, the processor 41 checks whether the channel of the address address is in use from the start address of the channel information storage unit 46 (ST6), and at this time, the channel of the address address is in use ('1'). If it is found to be, this means that there is no available channel, and the above-mentioned checking operation is repeated until the valid channel is confirmed by increasing the address '1'. (ST7)

When a channel having a channel state of '0' is identified, the processor 41 checks whether a channel to be used as a transmission channel (TX) is currently allocated to the caller (ST8). The effective channel identified in step ST6 is allocated to the transmission channel (ST9), and then the corresponding channel information allocated is recorded in the transmission channel assignment information storage unit 48. (ST10)

On the other hand, if it is determined in step ST8 that the transmission channel TX is already allocated, the processor 41 allocates the indexed valid channel to the channel to be used by the caller as the reception channel RX (ST11). The corresponding channel information assigned as a receiving channel is recorded in the receiving channel allocation information storage unit 49 (ST12), and at the same time, the data stored in the transmission channel allocation information storage unit 48 is read out and based on them. By transmitting the channel information assigned as the transmission channel and the reception channel to both stations, the transmission / reception channel necessary for bidirectional voice communication is allocated. (ST13)

Subsequently, the processor 41 changes and sets the corresponding address data of the channel information storage unit 46 to '1' (ST14), and then checks the drawing so that a message indicating that the call is terminated is transmitted from the call base station. ST15), the corresponding address data of the channel information storage unit 46 is set to '0' (ST16), and the channel for the call request is cleared by clearing the transmission / reception channel allocation information storage units 48 and 49. The assignment and all channel management operations are terminated. (ST17)

That is, according to the above embodiment, the two available channels identified by the effective channel search for the subscriber's call request are sequentially made into the transmission (TX) channel and the reception (RX) channel required for two-way voice communication. By assigning, it is possible to more efficiently manage the call channel provided between the two subscribers.

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.

Claims (1)

In a satellite communication system in which a plurality of base stations, each of which is combined with a plurality of subscribers, can be connected through a satellite to perform communication between arbitrary base stations, an effective channel search step of searching for an available channel available for a call request of any subscriber. And a first channel assignment step of allocating the effective channels indexed in this effective channel search step as a first channel for bidirectional voice communication, a channel assignment status checking step of confirming whether or not the first channel is assigned. A second channel search step of searching for an effective channel for the second channel assignment when the first channel is identified as assigned in the channel assignment status checking step; and for the bidirectional communication of the effective channel indexed in the second channel search step The second channel allocation step of allocating the second channel and the channel information allocated to the first and second channels are transmitted to both stations to allocate a transmission / reception channel. A method of allocating a transmit / receive channel for two-way voice communication of a satellite communication system, comprising: a channel assignment step.