KR980013009A - A method of assigning a transmission / reception channel for bi-directional voice communication in a satellite communication system - Google Patents

Abstract

The present invention is based on the fact that, in response to a subscriber's call request, two available channels confirmed by an effective channel search are sequentially backgrounded on a transmission (TX) channel and a reception (RX) channel required for bidirectional voice communication To a method for assigning a transmission / reception channel for bi-directional voice communication in a satellite communication system adapted to provide a communication channel between subscribers. A satellite communication system in which a plurality of base stations, each of which is defective with a plurality of subscribers, are connected to each other via satellites to perform communication between arbitrary base stations, comprising: an effective channel search step A first channel assignment step of assigning an effective channel indexed in the effective channel search step to a first channel for bidirectional voice communication; and a channel assignment state confirmation step of spreading whether the first channel is allocated or not. A second channel searching step of searching for an effective channel for the second channel allocation when the first channel is identified as being allocated in the channel assignment status checking step; To the second channel for the second channel. And a channel allocation step of transmitting channel information allocated to the first and second channels to both base stations and allocating a transmission / reception channel.

Description

A method of assigning a transmission / reception channel for bi-directional voice communication in a satellite communication system

In particular, the present invention relates to a satellite communication system, and more particularly to a satellite communication system in which two available channels confirmed by an effective channel search for a subscriber's call request are divided into a transmission channel (TX channel) and a reception channel (RX) required for bidirectional voice communication. Channel for voice communication in a satellite communication system in which a channel is provided between two subscribers by sequentially assigning the channels to the subscribers.

Generally speaking, a voice communication using a satellite refers to providing a two-way communication service so that a voice communication can be executed between two subscribers at a remote place through a geostationary satellite raised above an altitude of 36000 km. (Demand Assignment Multiple Access) satellite communication system in which a communication channel is allocated according to a request.

In FIG. 1, reference numeral 1 denotes a satellite having a plurality of communication channels, reference numeral 2 denotes a central control station for controlling the entire satellite communication system, reference numeral 3A and 3B denote exchangers IIA and IIB and telephones 12A and 12B ), A data terminal 13A, 13B such as a computer, and a terminal such as a maximali 14A, 14B, and also has an interface function between the central terminal 2 And provides a call function.

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

In the above configuration, the central control station 2 periodically transmits a message through a service channel of a TDM (Time Division Multiplex) scheme, and then transmits the message from the detached base station 3 in a Slotted Aloha A polling function for analyzing the response message and checking the state of each base station 7, that is, the use state of the communication channel or the communication channel, is performed. And. If there is a call request from a specific base station, for example, the base station 3A to a terminal of the base station 3B, the base station 3B determines whether the base station 3B is capable of interleaving based on the information obtained in the polling process, In the communication enabled state, the available traffic channels T of the satellites are allocated to the base stations 3A and 3B so that the base stations 3A and 3B can directly perform mutual communication.

Thereafter, when the communication between the base stations 3A and 3B is terminated and the communication end signal is applied from the base station 3A that has requested the communication through the service channel 5, The communication end processing is executed to release the traffic channel T that was provided to both the base stations 3A and 3B.

On the other hand, the radio resources that the satellite system can provide. That is, the number of communication channels is related to the specification of a transponder that is searched for in the satellite 1, and FIG. 2 shows a satellite repeater having a bandwidth of 36 MH7 to describe a communication channel provided by the satellite repeater transponder according to an embodiment of the present invention.

In the channel state illustrated in FIG. 2, one TDM channel and one S / A channel are accommodated one before the other and are allocated before and after the possible frequency band, respectively. The control data to be transmitted from the central control station 2 to the base station 3 side is transmitted in a TDM manner with a frequency band of 83.2 KH7 while the control data transmitted from the base station 3 side to the central control station 2 The data is transmitted in the S / A scheme having a frequency band of 41.6 KH7. Therefore, considering this, as shown in FIG. 2, Three channels (90Kindan a) among the 1200 communication channels divided into units are TDM type service channels 5 and at least two channels 60KH7 are fixed as S / A type service channels 5, respectively And the remainder is used as the traffic channel T.

For bi-directional voice communication, two channels, that is, a transmission channel (TX) and a reception channel (RX) are required to be expanded. When a call request is made from an arbitrary subscriber, It is necessary to efficiently select two channels and allocate them as a transmission channel (T ◎) and a receiving channel (RX) necessary for communication between the two subscribers.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method and apparatus for transmitting two available channels confirmed by an effective channel search to a subscriber's call request, RX) channels, respectively, in order to provide two-way voice communications between the two subscribers.

In order to achieve the above object, a method for allocating a transmission / reception channel for bidirectional voice communication in a satellite communication system according to the present invention is a method for allocating a plurality of base stations, which are combined with a plurality of subscribers, A valid channel searching step of searching for an effective channel usable for a call request of an arbitrary subscriber; and an effective channel searching step of assigning an effective channel indexed in the effective channel searching step to a first channel for bidirectional voice communication A channel assignment status confirmation step of confirming whether the first channel is allocated, a step of confirming whether or not the first channel is allocated, A second channel searching step of searching for a channel, a valid channel indexed in the second channel searching step, to a second channel for bidirectional communication And a channel allocation step of allocating a transmission / reception channel by transmitting the channel information allocated to the first and second channels to both base stations.

That is, according to the present invention having the above-described configuration, two available channels confirmed by the effective channel search for the subscriber's call request are transmitted to the transmission channel (TX channel) and the reception channel (RX) necessary for bidirectional voice communication (trarfic) Channels, the available radio resources can be optimized and utilized.

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

FIG. 3 is a block diagram showing a configuration of a central control station 7 that executes the above-described transmission / reception channel assignment function.

3, reference numeral 21 denotes an antenna for transmitting and receiving a down link signal transmitted from the satellite side as opposed to an up link signal transmitted to the phosphorescent satellite 1, An orthogonal mode converter (OMT) 30 for inputting and outputting a signal transmitted and received through the antenna 22, and a demodulator 23 for demodulating the signals inputted through the orthogonal mode converter 22, for example, 12.25 A low noise amplifier (LNA: Lew N7i7e Amplirier) 24 for low noise amplifying the downlink frequency signal of 12.75 eH7, 24 for converting an applied frequency signal through this low noise amplifier 23 into an intermediate frequency signal If of 7077H7 Frequency down converter (DC down converter).

Reference numeral 75 denotes a frequency division multiplexer for separating and outputting the intermediate frequency signal If supplied from the frequency down converter 24 into a plurality of intermediate frequency signals and outputting a single channel per channel (SCPC) channel unit (IF C / D 'If Combiner / Distributor) for outputting an intermediate frequency signal from the intermediate frequency provision / distribution unit 25, An SCPC channel unit for demodulating, decoding, and outputting a frequency signal. Here, the intermediate frequency combination / distribution unit 25 is employed for system scalability when a plurality of SCP near channel units are used.

Reference numeral 31 denotes an SCPC channel unit for encoding and modulating a message output from the network control unit 40 to be described later and 32 denotes an IF signal of 70 MHz applied from the IF combination / An up-converter (UC) 33 for converting an up-link frequency signal into an ultrahigh-frequency signal of 14.0 to 14.5 GHz to generate an up-link frequency signal, a reference numeral 33 denotes a high- (HPA: High Power Amplifier).

Reference numeral 40 denotes a splicing function for sending a control message to each base station 3 through the SCPS channel unit 26 and then checking the status of each base station 3 based on a response message transmitted from the corresponding base station If there is a call request from a specific base station, it is determined whether the other base station can communicate with the other base station based on the information obtained in the polling process. If the communication is enabled, the available traffic channel of the satellite T to the base stations so that both base stations can directly perform mutual communication, and the like.

Reference numeral 50 denotes a network management system for the system manager to manage the overall network of the satellite communication system by managing the network control unit 40.

4 is a block diagram schematically showing the configuration of the network control unit 40. Reference numeral 41 in FIG. 4 is a processor for controlling call processing between the base stations, in addition to controlling the entire system. 42 extracts packet information from a message received from the SCPC channel unit 26 and adds a Sloted ALOHA (S-ALOHA) packet to the SCPC channel unit 31 to generate TDM (SCC) service channel controller for generating and outputting a message of a multicast stream.

Reference numeral 43 is a dual port RAM, which is provided for data transmission / reception between the processor 41 and the service channel controller 42.

Reference numeral 44 denotes a program storage unit in which an operation program of the processor 44 is stored. Reference numeral 45 denotes a base station information storage unit in which state information of each base station obtained by the polling operation of the network processor 40 is stored. Is a channel information storage unit in which the use state of the communication channel allowed by the satellite is refurbished.

5 is a diagram showing memory mapping of the channel information storage unit 46. The channel information storage unit 46 stores the channel mapping information in the channel information storage unit 46, Quot; 0 "or" 1 "is stored in each storage area depending on whether the communication channel corresponding to the address is used or not. The binary data is set by the processor 41 according to the use state of the communication channel.

As shown in FIG. 5, the channel information storage unit 46 has a storage area for 1200 channels, and three channels allocated to the TDM channel and two channels allocated to the S / A channel The processor 41 controls the channel to not be allocated to the traffic channel T by setting the data of the corresponding address to "1" at all times.

That is, when there is a call request from an arbitrary base station, the processor 41 examines a communication channel written as "0" in the channel information storage unit 46 when the busy state of the communication channel is & By assigning to the calling base station and the called base station, both base stations are enabled to communicate directly via this assigned communication channel. And. This allocation of the communication channel is performed by sending a message to both base stations. At this time, the corresponding area of the channel information storage unit 46 which communicates with the assigned communication channel is set to "1 " .

When a communication termination message is transmitted from the calling base station after the communication channel is allocated, the processor 41 sends a message indicating that the communication has been terminated to the base stations where the communication has proceeded, The communication end processing is executed by setting the area again to "0 ".

Reference numeral 48 denotes a transmission channel allocation information storage unit for storing channel information of the first validated channel to be allocated to a transmission channel under the control of the processor 41. Reference numeral 49 denotes a second channel allocation information storage unit And a channel allocation information storage unit for storing channel information of the validated channel.

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

In the normal state, the network controller 40 of the third degree performs a polling operation to check the state of each base station.

That is, the processor 41 of the network controller 40 writes the packet data for checking the status of each base station to the dual port RAM 43, and the service channel controller 42 controls the dual port RAM 43 to generate a message of the TDM stream, and output the message to the SCPC channel unit 31. [

Then, the SCPC channel unit 31 encodes and modulates the message to convert it into an intermediate frequency signal of, for example, 70 MHz, and outputs the intermediate frequency signal. The intermediate frequency signal is combined on a frequency by frequency basis in the IF combination / And is converted into an uplink frequency signal of, for example, 14.5 GHz by the intermediate conversion section 32. [ And. The uplink frequency signal is output through the high-power amplifier 33, the orthogonal mode converter 22 and the antenna 21, and then transmitted to each base station 31 through the satellite 1 in FIG. 1 .

The downlink frequency signal of 12.25 GHz received from each base station 3 via the antenna 1 through the antenna 21 is transmitted through the orthogonal mode transformer 22 and the low noise amplifier 23 to the frequency Down converter 24 to be converted into an intermediate frequency signal of 70 MHz and applied to the SCPC channel unit 26 through the IF combining / distributing unit 25 to be demodulated and decoded and then supplied to the network controller 40 .

The network controller 40 extracts the packet information from the message to which the service channel controller 42 applies, generates the S-ALOHA packet, and writes it into the dual port RAM 43. The processor 41 reads the packet data from the dual port RAM 43 and updates the base station information storage unit 45 based on the read packet data, thereby holding status information on each base station.

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

Hereinafter, the transmission / reception channel allocation operation will be described in more detail with reference to the flowchart of FIG.

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 is received from the satellite 1 via the antenna 21 in the third degree, (ST1), the processor 41 reads the status information of the called base station from the base station information storage unit 45 (ST2), and if the corresponding packet data is inputted from the service channel controller 42 of the base station 40 (ST3). At this time, if the calling base station is unable to communicate due to medium reason, the processor 41 sends a call disabled message to the calling base station (ST4), the channel allocation operation is terminated. 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 corresponding address is in use from the start address of the channel information storage unit 46. At this time, the channel of the corresponding address is in a busy state ("1 & If it is determined that there is no usable channel, the confirmation operation is repeated until the effective channel is ascertained while increasing the address by "1". (577)

When the channel having the channel status of '0' is confirmed, the processor 41 confirms whether the current caller is in a state where the channel to be used as the transmission channel (T ⊚) is allocated (578), and if it is not yet assigned The effective channel identified in step 576 is allocated to the transmission channel (577), and the corresponding channel information allocated subsequently is recorded in the transmission channel allocation information storage unit 48. (5710)

If it is determined in step 578 that the TX channel has already been allocated, the processor 41 allocates the indexed effective channel to the channel to be used as the reception channel RX by the caller in step 5711, The corresponding channel information allocated as the reception channel is written (5712) in the reception channel allocation information storage unit 49, and at the same time, the data stored in the transmission channel allocation information storage unit 48 is read out, The transmission / reception channel required for bi-directional voice communication is allocated (5713), and then the processor 41 transmits the corresponding address of the channel information storage unit 46 (5715). If a message indicating that the call has been terminated is transmitted from the paging base station (5715), it is checked whether the message corresponding to the correspondence of the channel information storage unit Is not changed setting data to "0", and 5716 ends the channel allocation and various channel management operation for the transmission / reception channel assignment information call by clearing the storage section (4e) (49) required. (5717)

That is, according to the embodiment, the two available channels confirmed by the effective channel search for the subscriber's call request are sequentially transmitted (TX) and received (RX) channels required for bidirectional voice trunking It is possible to more efficiently manage the communication channel provided between the two subscribers.

While the present invention has been described in connection with certain embodiments, it is obvious that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities.

FIG. 1 is an overall system configuration diagram for explaining an outline of a general satellite communication system. FIG.

FIG. 2 is a view showing a state of channel division of a satellite transponder mounted inside the satellite 1 shown in FIG.

FIG. 3 is a block diagram showing in detail the configuration of the central control station 2 shown in FIG. 1,

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

5 shows a memory map of the channel information storage unit 46 shown in FIG. 4,

FIG. 6 is a flowchart for explaining a channel allocation process of a device having a configuration of FIG. 4; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

1: satellite, 2: central control station,

3A, 3B: base station, cIA, lIB: exchanger,

12A, 12B: telephone, 13A, 13B: data terminal,

14A, 14B: Wix Milly, 21: Andena,

22: orthogonal mode converter. 23: Low Noise Amplifier.

24: crusher down converter, 25: intermediate frequency combining /

26, Long: SCPC channel unit, 32: Frequency up converter.

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

41: processor, 42: service channel,

43: dual-port RAM, 44: program storage,

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

48: transmission channel allocation information storage unit, 49: reception channel allocation information storage unit.

50: Network Management System

Claims (1)

A satellite communication system in which a plurality of base stations, each associated with a plurality of subscribers, are combined via a satellite so as to be able to perform communication between any of the base stations. A first channel allocation step of allocating an effective channel indexed in the effective channel search step to a first channel for bidirectional voice communication, searching for an effective channel usable for a call request of an arbitrary subscriber, A channel assignment status confirmation step of confirming whether a channel is allocated to the first channel, a second channel search for searching an effective channel for the second channel allocation when the first channel is identified as being allocated in the channel assignment status confirmation step, A second channel assignment step of assigning an effective channel indexed in the second channel search step to a second channel for bidirectional communication, and a second channel assignment step of transmitting channel information assigned to the first and second channels to both base stations, And allocating a reception channel to each of the plurality of channels in the satellite communication system. ※ Note: It is disclosed by the contents of the first exhibition.