KR101213237B1 - Method for synchronization in satelite communication system based on frequency hopping, method for hop acquistion in terminal, and recording medium thereof - Google Patents

Abstract

PURPOSE: A synchronization method of a communication system, a synchronizing obtaining method of a terminal, and recording medium for the same are provided to extract visual information from a synchronization channel broadcasting signal and to obtain frequency synchronization. CONSTITUTION: A network control unit transmits a short code sequence including visual information to a terminal in a broadcasting type(S101). The terminal extracts the visual information of the network control unit from the short code sequence through a synchronization channel(S102). The terminal obtains frequency synchronization of the terminal by reflecting system delay information predefined to the extracted visual information(S104). The terminal generates a frequency hopping sequence based on the extracted visual information(S105). The terminal switches the generated frequency hopping sequence into a control channel(S106). [Reference numerals] (AA) Start; (BB) End; (S101) Transmitting a short code sequence including visual information to a terminal in a broadcasting type; (S102) Extracting the visual information of the network control unit from the short code sequence through a synchronization channel; (S103) Generating the extracted visual information by reflecting system delay information; (S104) Obtaining frequency synchronization of the terminal by reflecting system delay information predefined to the extracted visual information; (S105) Generating a frequency hopping sequence based on the extracted visual information; (S106) Switching the generated frequency hopping sequence into a control channel

Description

Method for synchronization in satelite communication system based on frequency hopping, method for hop acquistion in terminal, and recording medium etc.

The present invention relates to a method of synchronizing a frequency hopping satellite communication system, a method of acquiring a hopping synchronization of a terminal, and a recording medium therefor. A synchronization method of a frequency hopping satellite communication system capable of acquiring a frequency hopping synchronization of a very long terminal, a method of obtaining a hopping synchronization of a terminal, and a recording medium therefor.

The frequency hopping satellite communication system has a function of providing a safe communication path even at a low / high threat level by frequency hopping. It has superior anti-jamming and interceptor performance compared to the DS (Direct-Sequence) method. For normal operation of such a satellite communication system, hop synchronization between a network controller and a terminal is essential.

In such a satellite communication system, a code having a very long hop cycle is used for robust anti-jamming and interceptor performance, and in order to obtain synchronization, information included in a GPS signal or a modulated beacon signal transmitted from a satellite to a terminal is generally used. Use

Considering the case of using a modulated beacon signal, the satellite communication system uses a continuous-wave beacon signal for the satellite's satellite orientation. However, the beacon signal for frequency hopping requires a CW beacon signal including a modulated signal rather than a simple CW beacon signal, which should be reflected in the satellite repeater in the design of the satellite communication system.

Simple CW beacon signals are intended for antenna orientation and can be pointed only by the strength of the received signal.In this case, antenna orientation can be achieved only with a hardware-received signal strength indicator (RSSI) chip. Can be processed.

However, in case of modulation beacon, the antenna is pointing by using CW included in the modulation beacon, and a separate DSP, RAM, FPGA, and other chips for demodulating the modulated signal, that is, time information (TOD) A receiving interface circuit (modulated beacon receiver) is required.

Therefore, when visual information is transmitted using a modulation beacon, the visual information must be received through a separate modulation beacon receiver and transmitted to the visual information generator.

In addition, when the GPS signal is used, the time information of the terminal is set based on the time information of the GPS. To this end, a separate GPS receiver for receiving the GPS signal is required, and an interface for this is required.

As such, when a separate modulation signal receiver or a GPS receiver is attached to the terminal to receive visual information through the terminal, a terminal that is easy to carry and move like a vehicle terminal does not have great difficulty, but in the case of a small portable terminal, There is a disadvantage of increasing the volume and weight of the equipment, power consumption according to the provision of a separate hardware equipment. In addition, the complexity due to additional interface design increases.

An object of the present invention is to receive a synchronization channel broadcasting signal for short code sequence hopping including the time information of a network controller at a terminal of a frequency hopping satellite communication system, and extracts time information from the hopping period. Method of synchronizing a frequency hopping satellite communication system, which can easily acquire frequency hopping synchronization without requiring a separate hardware device for receiving visual information by acquiring a very long frequency hopping synchronization, and a terminal hopping The present invention provides a synchronization acquisition method and a recording medium therefor.

In order to achieve the above technical problem, the jump cycle according to the present invention is very long. A synchronization method of a frequency hopping satellite communication system, the method comprising: transmitting a short code sequence including time information of a network controller to a terminal through a synchronization channel in a broadcasting method; Extracting, by the terminal, time information of the network controller from the received short code sequence; A terminal acquiring a frequency hopping synchronization of the terminal by reflecting system delay information defined in the extracted time information; And generating, by the terminal, a frequency hopping sequence based on the time information extracted at the time when the frequency hopping synchronization is obtained, and switching from the synchronization channel to the control channel based on the generated frequency hopping sequence. The hopping sequence is a long code sequence having a longer code length than the short code sequence, and the system delay information is defined by summing the transmission time from the network controller to the terminal and the time for demodulating the short code sequence at the terminal.

delete

More preferably, the time information of the network controller may include a value of a timer of the network controller.

More preferably, the synchronization acquiring step may include: generating, by the terminal, corrected time information by reflecting system delay information predefined in the extracted time information; And updating, by the terminal, a timer of the terminal based on the generated correction time information.

More preferably, both the network controller and the terminal includes a time information generator, and the time information generator includes: a clock generator for generating a clock corresponding to a hopping period of the satellite communication system in the network controller; A time information generation unit generating synchronized time information based on a clock generated by the network controller, or extracting time information of the network controller from a short code sequence received at the terminal, and generating corrected time information reflecting system delay information; A timer for maintaining time information of each of the network controller and the terminal; A timer controller for resetting the timer or updating the timer based on the time information generated by the time information generator; And a controller for monitoring a synchronization state between the network controller and the terminal.

In order to achieve the above technical problem, according to the present invention, a method for acquiring frequency hopping synchronization of a terminal of a satellite communication system, receiving a short code sequence including time information of a network controller transmitted by a broadcasting method from a network controller step; Extracting time information of the network controller from the received short code sequence; A jump synchronization acquisition step of acquiring a frequency hopping synchronization of the terminal by reflecting the system delay information defined in the extracted time information; And at the time when the frequency hopping synchronization is obtained, switching from the synchronization channel to the control channel, generating a frequency hopping sequence based on the extracted visual information, and transmitting the generated frequency hopping sequence to the network controller through the switched control channel. The frequency hopping sequence generated here is a long code sequence having a longer code length than the short code sequence, and the system delay information includes a transmission time from the network controller to the terminal and a time for demodulating the short code sequence at the terminal. The sum is defined.

More preferably, the hopping synchronization acquisition step may include: generating, by the terminal, corrected time information by reflecting system delay information defined in the extracted time information; And updating, by the terminal, a timer of the terminal based on the generated correction time information.

In order to achieve the above technical problem, according to the present invention, a computer-readable recording medium containing a program including a frequency hopping synchronization acquisition function of a terminal of a satellite communication system is a network controller transmitted by a broadcasting method from a network controller. Receiving a short code sequence comprising visual information of the short code sequence; Extracting time information of the network controller from the received short code sequence; A function of acquiring frequency hopping synchronization of the terminal by reflecting the system delay information defined in the extracted time information and reflecting the system delay information defined in the extracted time information; And a function of switching from the synchronization channel to the control channel at the time of obtaining the frequency hopping synchronization, generating a frequency hopping sequence based on the extracted visual information, and transmitting the generated frequency hopping sequence to the network controller through the switched control channel. The frequency hopping sequence is a long code sequence having a longer code length than the short code sequence, and the system delay information is defined by summing the transmission time from the network controller to the terminal and the time for demodulating the short code sequence at the terminal. Contains the programmed program.

According to the present invention, the terminal of the satellite communication system, which is a frequency hopping system having a very long hopping period, does not require a separate hardware device such as a modem for receiving a GPS signal or a modulated beacon signal of the satellite. This allows the hopping synchronous of very long frequency hopping systems.

In particular, according to the present invention, it is possible to minimize the hardware configuration of the terminal to minimize the volume, weight, power consumption of the terminal device, and reduce the complexity of the synchronization process.

1A is a diagram showing the structure of a satellite communication system according to an embodiment of the present invention.
1B is a diagram illustrating a flow of a synchronization method between a network controller and a terminal in a satellite communication system according to an exemplary embodiment of the present invention.
2A is a block diagram illustrating the structure of a time information generator provided in a network controller and a terminal of a satellite communication system according to an embodiment of the present invention.
2B is a block diagram illustrating an example of a frequency hopping generator provided in a terminal of a satellite communication system according to an exemplary embodiment of the present invention.
3 is a diagram illustrating a structure of a sync channel message broadcast in a short code sequence in a network controller according to an embodiment of the present invention.
4 is a diagram illustrating transmission and reception timing of a network controller and a terminal mountain configured according to an exemplary embodiment of the present invention.

The following merely illustrates the principles of the invention. Thus, those skilled in the art will be able to devise various apparatuses which, although not explicitly described or shown herein, embody the principles of the invention and are included in the concept and scope of the invention. Furthermore, all of the conditional terms and embodiments listed herein are, in principle, intended only for the purpose of enabling understanding of the concepts of the present invention, and are not intended to be limiting in any way to the specifically listed embodiments and conditions . It is also to be understood that the detailed description, as well as the principles, aspects and embodiments of the invention, as well as specific embodiments thereof, are intended to cover structural and functional equivalents thereof. In addition, these equivalents should be understood to include not only equivalents now known, but also equivalents to be developed in the future, that is, all devices invented to perform the same function regardless of structure.

Thus, the functions of the various elements shown in the drawings, including the functional blocks shown in the figures or similar concepts, may be provided by use of dedicated hardware as well as hardware capable of executing software in connection with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared. Also, the use of terms such as processor, control, or similar concepts should not be construed as exclusive reference to hardware capable of executing software, but may include, without limitation, digital signal processor (DSP) hardware, (ROM), random access memory (RAM), and non-volatile memory. Other hardware may also be included.

The above objects, features and advantages will become more apparent from the following detailed description in conjunction with the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

On the other hand, when an element is referred to as "including " an element, it does not exclude other elements unless specifically stated to the contrary.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1A is a diagram illustrating a structure of a satellite communication system according to an exemplary embodiment of the present invention, and FIG. 1B is a diagram illustrating a flow of a synchronization method between a network controller and a terminal in the satellite communication system shown in FIG. 1A. .

Referring to FIG. 1A, in the satellite communication system 100 according to the present embodiment, the network controller 110 includes a network controller 110 for controlling the entire network of the satellite communication system, and a plurality of terminals 120-1 and 120-. 2, 120-3) and a relay satellite 130 for relaying communication between them.

The logical channel structure used in the link between the network controller 110 and the plurality of terminals 120-1, 120-2, and 120-3 connected through the relay satellite 130 is largely a synchronization channel and a control channel. It is divided into three channels of call channel.

The synchronization channel is a channel for transmitting and receiving pilot signals for synchronizing synchronization between the network controller 110 and the plurality of terminals 120-1, 120-2, and 120-3.

The control channel is a channel that transmits and receives a control signal for transmitting the state information of each of the terminals 120-1, 120-2, and 120-3 and call control information from the network controller 110.

The state information of each of the terminals 120-1, 120-2, and 120-3 may include a subscription state, a failure information, a reception state, and the like of each of the terminals.

The call channel is a channel for transmitting / receiving voice / data signals for transmitting voice or serviced data through the terminals 120-1, 120-2, and 120-3.

Referring to FIG. 1B, first, the network controller 110 generates time information (TOD, Time of date) and broadcasts a short code sequence including the terminal 120-1, 120-2, 120-in a broadcast manner. 3) Each of them is transmitted through a synchronization channel (S101).

Here, the time value of the network controller may be used as the time information of the network controller, but this is only one embodiment, and the present invention is not limited thereto.

Each of the terminals 120-1, 120-2, and 120-3 receives the short code sequence of the synchronization channel and extracts time information of the network controller from the received short code sequence (S102).

Each of the terminals 120-1, 120-2, and 120-3 generates corrected time information by reflecting system delay information defined in the time information extracted in step S102 (S103).

The system delay information may be defined by summing the transmission time from the network controller to the terminal and the time for demodulating the short code sequence in the terminal.

Each of the terminals 120-1, 120-2, and 120-3 obtains a frequency hopping synchronization of the terminal by updating a timer of the terminal based on the correction time information generated in step S103 (S104).

Each of the terminals 120-1, 120-2, and 120-3 generates a frequency hopping sequence based on the time information extracted in step S102 at the time when frequency hopping synchronization is obtained (S105), and then immediately generates the frequency. The switching from the synchronization channel to the control channel is based on the hopping sequence (S106).

Here, the frequency hopping sequence is a long code sequence having a longer code length than the short code sequence. This is to improve anti-jamming performance.

As such, as the long code sequence having a longer code length than the short code sequence is used as the frequency hopping sequence, the period of the long code sequence becomes considerably longer than that of the short code sequence, making synchronization difficult.

For example, it is assumed that the case where the number of registers constituting the code is less than 10 is a short code, and the case where the number of registers constituting the code is 20 or more is long code.

In the case where there are six registers of the short code and the clock of the code generator is 1 kHz, the period of the short code is (2 ^ 6) * (1 / 1k) = 0.064 sec.

On the other hand, in the case where there are 30 long code registers and the code generator has a clock of 1 kHz, the long code period is (2 ^ 30) * (1 / 1k) = 1073741.824sec.

In other words, to improve anti-jamming performance, long codes with relatively long code lengths should be used. However, since long periods are too long, synchronization becomes very difficult. Once synchronized, it is switched to long code.

When the control channel is switched in this way, the network controller and the terminal can communicate in a safe state from jamming through the switched control channel.

FIG. 2A is a block diagram illustrating a structure of a time information generator 140 commonly provided in the network controller and the terminal shown in FIG. 1, and FIG. 2B is a frequency hopping generator 150 provided in the terminal shown in FIG. 1. Is a block diagram illustrating an example of the present invention.

2A, the time information generator according to the present embodiment is a component commonly provided in the network controller and the terminal, and includes a clock generator 201, a time information generator 202, a timer 203, and a timer controller. 204 and the control unit 205.

The clock generator 201 generates a clock corresponding to the hopping period of the satellite communication system in order to synchronize the time information of the network controller with the hopping period in the network controller and the terminal. The terminal synchronizes with the synchronization channel signal leaping with the short code sequence to perform an early-late gate of the clock generator 201 to achieve clock synchronization with the clock generator of the network controller.

The time information generation unit 202 generates time information based on the clock generated by the network controller clock generator 201 and broadcasts it using a synchronization channel that hops to a short code sequence. The terminal extracts time information from the broadcast synchronization channel message received from the network controller, and generates the time information as the corrected time information by reflecting the predefined system delay information.

The timer 203 is a counter for maintaining time information of each of the network controller and the terminal.

The timer controller 204 resets the timer 204 or updates the timer based on the time information generated by the time information generator 202. In addition, it can perform a built-in-test (BIT) function to monitor whether the timer is operating properly.

The controller 205 may monitor whether the network synchronization state between the network controller and the terminal is properly maintained after the hopping synchronization is obtained through the frequency hopping generator illustrated in FIG. 2B.

If the network synchronization state between the network controller and the terminal is not properly maintained, the control unit 205 reports that the network synchronization state is not properly maintained to the main controller of the terminal and re-enters the message of the broadcasting synchronization channel of the network controller. You can request a scene and receive the visual information again.

That is, in the present invention, the terminal includes the visual information generator according to FIG. 2A in which the configuration of the conventional visual information generator is slightly changed, thereby eliminating a receiver of a separate complicated circuit such as a GPS receiver or a modulated beacon receiver, and thus the jump period is very high. It is possible to synchronize the leap of a long frequency hopping system (satellite communication system).

Referring to FIG. 2B, the frequency hopping generator according to the present embodiment receives a sequence generation parameter according to time information and generates a linear feedback shift register (LFSR) 211 for generating a series of binary bits and a sequence generation parameter according to time information. The multiplier 213 multiplying the state values output from the PCRs (Pure Cyclic Register, 212) and the LFSR 211 and the sequence output from each PCRemf 212 by bit unit, and the output of the multiplier Bit Serial Adder (BSA) 214 for generating a frequency hopping sequence of a desired length.

The frequency hopping generator shown in FIG. 2B is just one embodiment of a configuration for generating a frequency hopping sequence according to time information, and the present invention is not limited thereto.

3 is a diagram illustrating a structure of a sync channel message broadcast in a short code sequence in a network controller according to an embodiment of the present invention.

Referring to FIG. 3, the sync channel message according to the present embodiment includes a first field including communication protocol information of the sync channel message in total m bits, a second field including time information in total n bits, and a checksum (CRC). It may be composed of three fields of the third field for).

4 is a diagram illustrating transmission and reception timing of a network controller and a terminal mountain configured according to an exemplary embodiment of the present invention.

Referring to FIG. 4, first, the network controller transmits a short code sequence including time information to a terminal through a synchronization channel in a broadcast manner (S401).

In operation S401, the terminal receives a short code sequence of a synchronization channel (S402), demodulates the received short code sequence, and extracts time information (S403).

The synchronization is performed by reflecting the system information defined in the time information extracted in step S403 (S404). That is, at the time of S404 the terminal is switched from the synchronization channel to the control channel,

According to the present invention, frequency hopping synchronization can be more easily obtained without requiring a separate hardware device such as a modem for receiving a GPS signal or a beacon signal of a satellite in the terminal of the satellite communication system.

In particular, according to the present invention, it is possible to minimize the hardware configuration of the terminal to minimize the volume, weight, power consumption of the terminal device, and reduce the complexity of the synchronization process.

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers of the technical field to which the present invention belongs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

Claims (7)

A synchronization channel through which a network controller, a terminal, and a synchronization signal for synchronizing between the network controller and the terminal are transmitted and received, a control channel through which state information of the terminal and call control information from the network controller are transmitted and received, and a call through the terminal In the synchronization method of the frequency hopping satellite communication system comprising a relay satellite for relaying communication between the network controller and the terminal by forming a communication channel including a communication channel to be transmitted and received data and service data,
Transmitting, by the network controller, a short code sequence including time information including a timer value of the network controller to the terminal through the synchronization channel;
Extracting, by the terminal, time information of the network controller from a short code sequence received through the synchronization channel;
The terminal acquiring a frequency hopping synchronization of the terminal by reflecting the system delay information predefined in the extracted time information; And
The terminal generating a frequency hopping sequence based on the extracted time information at the time when the frequency hopping synchronization is obtained, and switching from the synchronization channel to the control channel based on the generated frequency hopping sequence;
The frequency hopping sequence is a long code sequence having a longer code length than the short code sequence,
And the system delay information is defined by summing the transmission time from the network controller to the terminal and the time for demodulating the short code sequence in the terminal. delete The method of claim 1,
The motivation acquisition step is
Generating, by the terminal, correction time information by reflecting system delay information predefined in the extracted time information; And
And updating, by the terminal, the timer of the terminal based on the generated corrected time information. The method of claim 3,
Both the network controller and the terminal has a visual information generator,
The time information generator,
A clock generator for generating a clock corresponding to a hopping period of the satellite communication system in the network controller;
The corrected time information by generating the synchronized time information based on the generated clock in the network controller, or extracting time information of the network controller from the received short code sequence at the terminal, and reflecting the system delay information. Visual information generation unit for generating a;
A timer for maintaining time information of each of the network controller and the terminal;
A timer controller for resetting the timer or updating the timer based on the time information generated by the time information generator; And
And a control unit for monitoring a synchronization state between the network controller and the terminal. A synchronization channel through which a network controller, a terminal, and a synchronization signal for synchronizing between the network controller and the terminal are transmitted and received, a control channel through which state information of the terminal and call control information from the network controller are transmitted and received, and a call through the terminal In the method of obtaining a frequency hopping synchronization of a terminal of a satellite communication system including a relay satellite for relaying communication between the network controller and the terminal by forming a communication channel including a communication channel to be transmitted and received data and service data,
Receiving a short code sequence including time information including a timer value of the network controller transmitted from the network controller in a broadcasting manner;
Extracting time information of the network controller from the received short code sequence;
A hop synchronization acquisition step of acquiring a frequency hopping synchronization of the terminal by reflecting the system delay information predefined in the extracted time information; And
Generating a frequency hopping sequence based on the extracted time information at the time when the frequency hopping synchronization is obtained, and switching from the synchronization channel to the control channel based on the generated frequency hopping sequence;
The frequency hopping sequence is a long code sequence having a longer code length than the short code sequence,
And the system delay information is defined by summing up the transmission time from the network controller to the terminal and the time for demodulating the short code sequence in the terminal. The method of claim 5,
The leap motivation acquisition step
Generating, by the terminal, correction time information by reflecting system delay information predefined in the extracted time information; And
And the terminal updating the timer of the terminal based on the generated corrected time information. A synchronization channel through which a network controller, a terminal, and a synchronization signal for synchronizing between the network controller and the terminal are transmitted and received, a control channel through which state information of the terminal and call control information from the network controller are transmitted and received, and a call through the terminal A program including a function of obtaining a leap synchronization of a terminal of a satellite communication system including a relay satellite configured to relay a communication between the network controller and the terminal by forming a communication channel including a communication channel through which voice and serviced data are transmitted and received; In the computer-readable recording medium recorded,
Receiving a short code sequence including time information including a timer value of the network controller transmitted from the network controller in a broadcasting manner;
Extracting time information of the network controller from the received short code sequence;
A function of acquiring frequency hopping synchronization of the terminal by reflecting system delay information predefined in the extracted time information and reflecting system delay information predefined in the extracted time information; And
Generating a frequency hopping sequence based on the extracted time information at the time when the frequency hopping synchronization is obtained, and switching from the synchronization channel to the control channel based on the generated frequency hopping sequence;
The frequency hopping sequence is a long code sequence having a longer code length than the short code sequence, and the system delay information is defined by adding up a transmission time from the network controller to the terminal and a time for demodulating the short code sequence at the terminal. A computer-readable recording medium containing a program including a function for obtaining a leap synchronization of a terminal of a satellite communication system.

Images