KR102061836B1 - Method and Apparatus for Generating Group-Wise Modulatable Orthogonal Codes, and Secure Communication System Using Them - Google Patents

Abstract

According to the present embodiments, the spreading codes are continuously changed using a random generator for each group while ensuring orthogonality of spreading codes, thereby providing orthogonality to the orthogonal spreading code itself and improving the security of synchronous DS-CDMA. Provides a method and apparatus for generating code.

Description

Method and apparatus for generating orthogonal spreading code which can be modulated by group, and non-communication communication system using same {Method and Apparatus for Generating Group-Wise Modulatable Orthogonal Codes, and Secure Communication System Using Them}

TECHNICAL FIELD The present invention relates to a method for generating a group coded orthogonal code group for a communication system, and a communication method and apparatus for a direct spread spectrum division multiple access method for performing secret communication using the same.

The contents described in this section merely provide background information on the present embodiment and do not constitute a prior art.

Direct Sequence Code Division Multiple Access (DS-CDMA) technology is used as a core technology for 2-3G mobile communication systems and GPS systems. DS-CDMA is based on Direct Sequence Spread Spectrum (DSSS), a kind of Spread Spectrum (SS) technology that divides one communication channel into multiple orthogonal or quasi-orthogonal channels to This is a method in which terminals share resources. Since DS-CDMA uses a specially designed spread code, it is widely used in the communication field where security is required.

DS-CDMA is classified into asynchronous DS-CDMA and synchronous DS-CDMA according to synchronization between signals. Asynchronous DS-CDMA performs communication by dividing a channel into a plurality of quasi-orthogonal channels, and can directly apply a method for improving security in direct spread spectrum. In asynchronous DS-CDMA requiring high security, a very long or random form of spreading code is used to prevent spreading code leakage and prediction.

In contrast, synchronous DS-CDMA has a constraint that all spreading codes used for channel division must be orthogonal to each other in order to split one channel into multiple orthogonal channels. Since synchronous DS-CDMA uses a fixed spreading code for the orthogonality of spreading codes, there is a problem that an attacker can acquire and intercept a fixed spreading code. In the conventional method, since it is impossible to give randomness to spreading codes while maintaining orthogonality, a scrambler is used to improve security.

Embodiments of the present invention continuously change the spreading code using a random generator for each group while guaranteeing the orthogonality of spreading codes based on the correlation characteristics of different Frank sequences, thereby giving randomness to the orthogonal spreading code itself. The main purpose of the invention is to make detection and prediction difficult, thereby improving the security of synchronous DS-CDMA.

Still other objects of the present invention may be further considered without departing from the following detailed description and effects thereof.

According to an aspect of the present embodiment, a method for using a spreading code in a wireless communication system, the method comprising: generating a basic code having a length of a natural number N as a length, and from 0 to a natural number of 1 less than the square of N; And generating a spreading code from the base code by using different random generators for each of the divided groups based on the remainder divided by the number of groups set to N for integers.

According to another aspect of the present embodiment, in a device using a spreading code in a wireless communication system, a basic code generating unit for generating a basic code having a length of a natural number N as a length, and from 0 to 1 less than the square of N Provides a spreading code using apparatus including a spreading code generating unit for generating a spreading code from the base code using a different random generator for each group divided based on the remainder divided by the number of groups set to N for integers up to a natural number do.

As described above, according to the embodiments of the present invention, each group of the orthogonal spreading codes is continuously changed according to a predetermined rule by using a different random number generator, thereby improving group unit security. In addition, it is difficult to estimate and recover even if a terminal outside the group takes over the spreading code, and improves the security of the spreading code itself. Therefore, the scrambler can be applied in the spreading step.

Even if the effects are not explicitly mentioned herein, the effects described in the following specification and the tentative effects expected by the technical features of the present invention are treated as described in the specification of the present invention.

1 illustrates a general synchronous DS-CDMA using an orthogonal code.
2 to 4 are block diagrams illustrating an apparatus for using a spreading code according to embodiments of the present invention.
5 is a block diagram illustrating a signal transmitter of a spreading code using apparatus according to an embodiment of the present invention.
6 is a diagram illustrating a correlation characteristic between different generalized Frank sequences.
7 to 10 are diagrams illustrating that a spreading code using apparatus generates a 9 length code and a spreading code according to an embodiment of the present invention.
11 to 13 illustrate a method of operating a spreading code of length 9 by a spreading code using apparatus according to an embodiment of the present invention.
14 is a flowchart illustrating a method of using a spreading code according to another embodiment of the present invention.

In the following description of the present invention, when it is determined that the subject matter of the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted, and some embodiments of the present invention will be omitted. It will be described in detail with reference to the exemplary drawings.

Embodiments described herein may be used in a wireless communication system.

The wireless communication system includes at least one base station (BS) and at least one user equipment (UE). Each base station provides a communication service for a cell, which is a specific geographic area. The cell may be further divided into sectors, which are sectors. Communication from the base station to the terminal is called downlink, and communication from the terminal to the base station is called uplink.

The base station is a station for communicating with the terminal and may be referred to by other names such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and the like.

A terminal is a device that communicates with a communication network and includes a mobile station (MS), a mobile terminal, a user terminal (UT), a subscriber station (SS), a wireless device, and a mobile device. It may be referred to by other names such as a personal digital assistant (PDA), a wireless modem, a handheld device, and the like.

Various multiple access transmission technologies may be applied to a wireless communication system. Multiple access is a technology for multiple users to share code, frequency, time, and space. Multiple accesses are divided into fixed and dynamic allocation approaches.

Examples of fixed allocation approaches include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency. Orthogonal Frequency Division Multiple Access (OFDMA) may be used, but is not limited thereto.

Examples of the dynamic allocation approach include, but are not limited to, Carrier Sense Multiple Access (CSMA).

Various duplexing techniques for bidirectional communication may be applied to the wireless communication system. Examples of the duplication technique include frequency division duplexing (FDD), time division duplexing (TDD), and the like, but are not limited thereto.

Multi-antenna technology may be applied to a wireless communication system. Multi-antenna is based on the configuration of the antenna, the single transmit antenna single input antenna (Single Input Single Output, SISO), the single transmit antenna multiple input antenna (SIMO), the multiple transmit antenna single input antenna (Multi Input Single Output) , MISO), and multiple transmit antennas (Multiple Input Multiple Output, MIMO). A transmit antenna means a physical or logical antenna used to transmit one signal or stream, and a receive antenna means a physical or logical antenna used to receive one signal or stream.

The wireless communication system may operate in a spread band communication method. In spread spectrum communication, a spreader spreads a spectrum of an information signal at a transmitter and transmits it, and a receiver despreads and restores a frequency spectrum of a received signal. There are two types of spread-band communication methods, direct sequence method and frequency hopping method, depending on the method of spreading the frequency spectrum of the information signal. DS-CDMA). The DS-CDMA method allocates a PN (pseudo-noise) sequence with excellent cross-correlation property to each user in order to minimize the interference between users while sharing time and frequency when multiple users use one radio channel. . Each user spreads and transmits a signal to be transmitted using the assigned PN sequence, and the receiving side generates and synchronizes the same PN sequence as used at the transmitting side, and uses the same to despread the received signal to restore a desired signal.

Conventional PN sequences used as spread codes in DS-CDMA communication systems include: (i) a binary PN sequence with a value of 0 or 1, (ii) a sequence with period N = 2 ⁿ -1, where n is an integer , N = 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, etc.), (iii) the periodic PN sequence s (t) = s (t + N) (0≤t≤N -1), (iv) m-sequences, etc., but existing PN sequences cannot generate spreading codes that secure orthogonality and randomness at the same time.

In a CDMA communication system, a forward channel is composed of a pilot channel, a sync channel, a paging channel, and a traffic channel. The pilot channel is an unmodulated CDMA channel signal that is always transmitted from a base station and is used to obtain initial synchronization for demodulation of a received signal at a mobile station. The synchronization channel is a channel that is always transmitted at the information rate of 1200bps from the base station. The information transmitted through the synchronization channel is offset of the pilot PN sequence for identifying the base station, the state of the register of the long code generator, and the current system time. Long-term synchronization and system timing can be obtained. The paging channel is a channel that is always transmitted from the base station and can transmit up to seven base stations. The mobile station responds to system information, commands or paging information for all or specific mobile stations, and when the mobile station requests access to the base station through this channel. Contains information such as messages. A traffic channel is a channel through which a base station transmits data or encoded voice information to a specific mobile station while a call is connected. The frame consists of 20 ms. The intensity of the transmitted signal power is controlled according to the transmission rate of the transmitted information.

In a CDMA communication system, a reverse channel includes an access channel and a traffic channel. An access channel is a channel used when a mobile station attempts to access a base station. When a user requests access to a base station, the mobile station attempts to connect to the base station through an access channel and receives and interprets all messages transmitted from the base station to the paging channel. Each access channel attempts access on a slot basis, and since the selection of slots is determined by a random process, mobile stations that multiple mobile stations transmit on the same channel and slot during a call view may occur. The traffic channel is a channel for transmitting data or encoded voice data as in the forward case. Unlike the forward channel, the reverse traffic channel transmits voice data by adjusting a duty cycle while maintaining a constant output power instead of changing the power of the output signal at different information rates.

1 illustrates a general synchronous DS-CDMA using an orthogonal code. Orthogonal codes are used in CDMA, which are called Walsh codes or Hadamard Matrix. The Hadamard matrix consists of binary +1 and -1 elements, which are used for the spreading of the signal and user identification in the forward channel of the IS-95, and the Hadamard matrix for the modulation of the signal in the reverse channel. It is used. Since synchronous DS-CDMA uses a fixed spreading code, there is a problem that an attacker can obtain and eavesdrop a fixed spreading code.

Hereinafter, an apparatus for using a spreading code and a communication system using the same may be used to secure randomness in spreading codes on a group basis while maintaining orthogonality. The spreading code using device may be implemented as part of a wireless communication system.

2 to 4 are block diagrams illustrating an apparatus for using a spreading code according to embodiments of the present invention. As shown in FIG. 2, the spreading code using apparatus 200 includes a basic code generating unit 210 and a spreading code generating unit 220. The spreading code using apparatus 200 may omit some of the various components illustrated in FIG. 2 or may further include other components. For example, the spreading code using apparatus 300 may further include a signal transmitter 330.

The basic code generator 210, 310, or 410 generates a basic code having a length of a natural number N as a length. The basic code generator 210 or 310 generates a generalized Frank sequence. The basic code generators 210 and 310 allocate to the subscribers of N ² integers ranging from 0 to a natural number less than 1 squared to the subscribers of N squares. The basic code generator 210 or 310 calculates a modulo N obtained by dividing an assigned integer by the number of groups, and generates a group by collecting subscribers having the same value as the calculated remainder. The basic code generators 210 and 310 allocate a sequence of cyclic shifts of the Frank sequence by i * N + j to the j-th subscriber of the i-th group. Where i and j are natural numbers.

The spreading code generators 220, 320, and 420 use a random generator that is different for each divided group based on the remainder divided by the number of groups set to N for integers from 0 to a natural number less than N squared. Generate spreading code from code. The spreading code generators 220 and 320 set subscribers of the same group to have the same random generator. The spreading code generators 220 and 320 generate a spreading code by modulating the output of the random generator corresponding to each subscriber and multiplying the modulated random sequence by the allocated base code. The spreading code generators 220 and 320 generate a random sequence by repeating N times so that the output of the random generator corresponding to the remainder divided by the number of groups has a length of N squared. In order to modulate a random sequence, a phase shift keying (PSK) scheme for changing a carrier phase according to an information value of a digital signal may be applied.

The signal transmitters 330 and 430 spread and transmit the generated spreading code. Referring to Figure 4, there is N ² of the user code generator (401, 402) is shown. Each user code generator 402 includes a basic code generator 410 and a spreading code generator 420. The plurality of user code generators 401 and 402 transmit a spreading code to the signal transmitter 430. The signal transmitter 430 spreads the spreading codes C ₀ to _CN ² _-1 and user data, and transmits the spreaded signals to the outside. Referring to FIG. 5, the signal transmitter may further improve security by using each scrambler for N ² user data.

Hereinafter, orthogonality of the spreading codes generated by the spreading code using apparatus according to the present embodiment will be demonstrated.

이라고 할 때, 길이 N²인 N진 일반화된 프랭크 수열

의 n번째 원소는 수학식 1과 같이 표현된다.For any natural number N, we define g (x) as some substitution function in the N-number integer, and m (x) as any function defined in real.

, N-N generalized Frank sequences of length N ²

The nth element of is expressed as in Equation 1.

로 표현된다. 즉, (w_N)^N=1이다.In Equation 1

It is expressed as That is, (w _N ) ^N = 1.

에 대하여, 자기 상관이 0이다. 즉, 하나의 프랭크 수열의 자기 상관 특성은 수학식 2와 같이 표현된다.Generalized Frank's sequence is random function m (x) and random delay

For, the autocorrelation is zero. That is, the autocorrelation property of one Frank's sequence is expressed by Equation 2 below.

와

의 내적(Inner Product)은 0이다.therefore,

Wow

The inner product of is zero.

If the function g (x) is an arbitrary substitution function in the N binary integer ring, two different generalized Frank sequences generated from the function g (x) are expressed as in Equation (3).

에 대해서 서로 다른 일반화된 프랭크 수열의 상관 특성은 수학식 4와 같이 표현된다.When the generalized Frank sequences f ₁ and f ₂ are produced with the same g (x) and arbitrary m ₁ (x) and m ₂ (x), respectively,

The correlation characteristics of different generalized Frank sequences are expressed as in Equation 4 below.

와

는

일 때 직교한다. 도 6에서는 N=6, g(x)=x이고, 함수 m1(x)과 m2(x)는 각각 m1(0)=5, m1(1)=1, m1(2)=4, m1(3)=4, m1(4)=2, m1(5)=3, m2(0)=0, m2(1)=0, m2(2)=3, m2(3)=4, m2(4)=5, m2(5)=0이라고 할 때, 지연에 따른 서로 다른 일반화된 프랭크 수열 f₁과 f₂ 간의 상관 특성이 도시되어 있다. 본 실시예들은 서로 다른 플랭크 수열의 상관 특성을 이용하여 기본 코드를 할당하고 확산 코드를 생성한다.In other words,

Wow

Is

Orthogonal when In FIG. 6, N = 6, g (x) = x, and the functions m1 (x) and m2 (x) are m1 (0) = 5, m1 (1) = 1, m1 (2) = 4, m1 ( 3) = 4, m1 (4) = 2, m1 (5) = 3, m2 (0) = 0, m2 (1) = 0, m2 (2) = 3, m2 (3) = 4, m2 (4 When m = 5 and m2 (5) = 0, the correlation characteristics between the different generalized Frank sequences f ₁ and f ₂ according to the delay are shown. The present embodiments use the correlation characteristics of different flank sequences to allocate a base code and generate a spreading code.

Hereinafter, a basic code and a spreading code having a number of groups 3 and a length of 9 will be described as an example. 7 through 9 illustrate generation of a basic code and a spreading code of length 9.

For the generation parameter, the number of subscribers can be set to 3, the number of groups to 3, and the length of the orthogonal spreading code can be set to 9. The quotient and remainder of N divided by 3 are called q and r, respectively. That is, N = 3q + r. Here, the numerical values set in N and N ² are exemplary only, and are not limited thereto. Suitable numerical values may be used depending on the design implemented.

이고, 함수 g(x)는 g(0)=0, g(1)=1, g(2)=2라고 설정할 수 있다. 이 경우에 생성된 일반화된 프랭크 수열은

과 같이 표현된다.The generalized Frank sequence of length 9

The function g (x) can be set to g (0) = 0, g (1) = 1, g (2) = 2. In this case, the generated generalized Frank sequence

It is expressed as

이다. 확산 코드 생성 장치는 3으로 나눈 나머지 0에 대응하는 랜덤 발생기의 출력에 따라 {2,1,0}을 반복하여 반복 수열 {2, 1, 0, 2, 1, 0, 2, 1, 0}을 생성한다. 반복 수열을 PSK 변조하여 랜덤 수열

을 생성한다. 생성한 랜덤 수열과 기본 코드를 곱하여 확산 코드

를 생성한다.Referring to FIG. 7, the base code of subscriber 0 whose user index is 0 is a generalized Frank sequence.

to be. The spreading code generator repeats {2,1,0} according to the output of the random generator corresponding to the remaining 0 divided by 3, and repeats the sequence {2, 1, 0, 2, 1, 0, 2, 1, 0} Create Random sequence by PSK modulation of repeating sequence

Create Spread code by multiplying random sequence by base code

Create

이다. 확산 코드 생성 장치는 3으로 나눈 나머지 1에 대응하는 랜덤 발생기의 출력에 따라 {0,1,0}을 반복하여 반복 수열 {0, 1, 0, 0, 1, 0, 0, 1, 0}을 생성한다. 반복 수열을 PSK 변조하여 랜덤 수열

을 생성한다. 생성한 랜덤 수열과 기본 코드를 곱하여 확산 코드

를 생성한다.Referring to FIG. 8, the base code of subscriber 1 having a user index of 1 is a sequence that cyclically transitions a generalized Frank sequence

to be. The spreading code generating apparatus repeats {0,1,0} according to the output of the random generator corresponding to the remaining 1 divided by 3 and repeats the sequence {0, 1, 0, 0, 1, 0, 0, 1, 0} Create Random sequence by PSK modulation of repeating sequence

Create Spread code by multiplying random sequence by base code

Create

The spreading code generating apparatus generates the base code and the spreading code in the same manner from the user index 2 to N ² -1. The generated group, generated base code and spreading code are shown in FIG. That is, it shows the spreading codes of 9 subscribers generated using the basic code and the random number output.

Referring to FIG. 10, the spreading code generation device transmits data on a channel using a spreading code. At other times, different outputs of the random generator are used, and the rest of the schemes generate and use spreading codes in the same manner.

Hereinafter, a method in which a spreading code using device operates a spreading code will be described. 11 to 13 illustrate a scheme in which a spreading code using apparatus operates a spreading code having a length of 9 in a wireless communication system. The wireless communication system may be a communication system operating in a direct spread code division multiple access (DS-CDMA) scheme.

Referring to FIG. 11, a DS-CDMA communication system allocates one channel for each subscriber, and one subscriber may use one spreading code. This operation scheme does not allow any subscriber to infer spreading codes of subscribers of another group, but any subscriber can infer spreading codes of subscribers in the same group.

Referring to FIG. 12, a DS-CDMA communication system allocates one channel group for each subscriber, and one subscriber may use one spreading code group. In this operation method, since the subscriber occupies the entire group, other subscribers cannot infer the spreading code. However, the number of subscribers concurrently connected is reduced.

Referring to FIG. 13, the DS-CDMA communication system allocates one channel group for each subscriber according to a predetermined time, and a plurality of subscribers may time-division the spread code group. . It works in the form of time division-code division multiple access. This operation method can not infer the spreading code of other subscribers, it can solve the problem that the number of subscribers connected simultaneously due to time division multiple access.

Although components included in the spreading code using apparatus are illustrated separately in FIGS. 2 to 5, the plurality of components may be combined with each other and implemented as at least one module. The components are connected to the communication path connecting the software module or the hardware module inside the device and operate organically with each other. These components communicate using one or more communication buses or signal lines.

The spreading code using apparatus may be implemented in a logic circuit by hardware, firmware, software, or a combination thereof, or may be implemented using a general purpose or special purpose computer. The device may be implemented using a hardwired device, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. In addition, the device may be implemented as a System on Chip (SoC) including one or more processors and controllers.

The spreading code using apparatus may be mounted in a computing device provided with hardware elements in the form of software, hardware, or a combination thereof. The computing device includes various or all communication devices such as a communication modem for performing communication with various devices or wired and wireless communication networks, a memory for storing data for executing a program, a microprocessor for executing and operating a program, and the like. It can mean a device.

The receiving side of the wireless communication system may recover user data using a spreading code from a wireless signal received through a channel. The receiver of the wireless communication system can recover data by applying various code detection methods used in synchronous or asynchronous DS-CDMA. This is only an example and is not limited thereto. Can be.

14 is a flowchart illustrating a method of using a spreading code according to another embodiment of the present invention. The spreading code using method may be performed by a spreading code using device.

In step S1410, the spreading code using apparatus generates a basic code having a length of the natural number N as the length. Generating a basic code (S1410) generates a Frank sequence, assigns to the subscribers of N squared integers from 0 to a natural number less than 1, and divides the assigned integer by the number of groups. (modulo N) is calculated, and the remainder of the calculated groups of subscribers having the same value are created. Generating the basic code (S1410) allocates a sequence of cyclic shifts of the Frank sequence by i * N + j (i and j are natural numbers) to the j-th subscriber of the i-th group.

In step S1420, the spreading code using apparatus spreads from the base code using a different random generator for each group divided based on the remainder divided by the number of groups set to N for integers from 0 to a natural number less than 1 squared of N. Generate the code. Generating a spreading code (S1420) sets subscribers of the same group to have the same random generator, modulates the output of the random generator, and multiplies the assigned base code to generate a spreading code. Generating a spreading code (S1420) is repeated N times so that the output of the random generator corresponding to the remainder divided by the number of groups has a length of N squared, and generates a sequence with the output of the random generator.

The spreading code usage method may further include spreading and transmitting the generated spreading code.

The wireless communication system to which the spreading code usage method is applied may be a communication system operating in a direct spread code division multiple access (DS-CDMA) scheme. A DS-CDMA communication system allocates one channel for each subscriber, and one subscriber can use one spreading code. The DS-CDMA communication system allocates one channel group for each subscriber, and one subscriber can use one spreading code group. In the DS-CDMA communication system, one channel group is allocated to each subscriber according to a predetermined time, and a plurality of subscribers may time-division the spreading code group.

Although each process is described as being sequentially executed in FIG. 14, this is merely illustrative, and a person skilled in the art may change the order described in FIG. 14 without departing from the essential characteristics of the exemplary embodiment of the present invention. It may be possible to apply various modifications and variations, or to execute one or more processes in parallel or to add other processes.

The operations according to the embodiments may be implemented in the form of program instructions that may be executed by various computer means and may be recorded in a computer readable medium. Computer-readable media refers to any medium that participates in providing instructions to a processor for execution. Computer-readable media can include program instructions, data files, data structures, or a combination thereof. For example, there may be a magnetic medium, an optical recording medium, a memory, and the like. The computer program may be distributed over networked computer systems so that the computer readable code is stored and executed in a distributed fashion. Functional programs, codes, and code segments for implementing the present embodiment may be easily inferred by programmers in the art to which the present embodiment belongs.

The present embodiments are for describing the technical idea of the present embodiment, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

200, 300: device using spreading cord
210, 310, 410: basic code generator
220, 320, 420: spreading code generation unit
330, 430: signal transmitter
401, 402: user code generator

Claims (20)

In the method using a spreading code in a wireless communication system,
Generating a basic code having a length of a natural number N squared; And
Generating a spreading code from the base code using a random generator that is different for each divided group based on the remainder divided by the number of groups set to N for integers from 0 to a natural number less than the square of N; Include,
The wireless communication system operates in a direct spread code division multiple access (DS-CDMA) scheme and is a synchronous DS-CDMA system.
The generating of the basic code may include generating a Frank sequence, assigning the subscribers of the square of N to integers from 0 to a natural number less than 1, and dividing the assigned integer by the number of groups. calculate modulo N, generate the group by collecting the subscribers having the same value
Subscribers belonging to the same group are set to have the same random generator, and subscribers of different groups are set to have different random generators. delete The method of claim 1,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel for each subscriber, and one subscriber uses one spreading code. The method of claim 1,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel group for each subscriber and uses one spreading code group for each subscriber. Way. The method of claim 1,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel group for each subscriber according to a predetermined time, and spreads the code by using a plurality of subscribers by time-dividing the spreading code group. How to use. delete The method of claim 1,
Generating the basic code,
And assigning a sequence of cyclic shifts of the Frank sequence by i * N + j (where i and j are natural numbers) to the j-th subscriber of the i-th group. The method of claim 1,
Generating the spreading code,
And modulating the output of the random generator and multiplying the assigned basic code to produce a spreading code. The method of claim 1,
Generating the spreading code,
And repeating N times so that the output of the random generator corresponding to the remainder has the length of the square of N and generating a sequence with the output of the random generator. The method of claim 1,
Spreading the generated spreading code and transmitting the spreading code. In a device using a spreading code in a wireless communication system,
A basic code generator for generating a basic code having a length of a natural number N as a length; And
A spreading code for generating a spreading code from the base code using a random generator different from each other based on the remainder divided by the number of groups set to N for integers from 0 to a natural number less than 1 of the square of N Including a generator,
The wireless communication system operates in a direct spread code division multiple access (DS-CDMA) scheme and is a synchronous DS-CDMA system.
The basic code generator generates a Frank sequence, allocates integers from 0 to a natural number less than 1 to the square of the subscriber, and divides the assigned integer by the number of groups (modulo N). ), Generate the group by collecting the subscribers having the same value
And the subscribers belonging to the same group are set to have the same random generator, and the subscribers of different groups are set to have different random generators. delete The method of claim 11,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel for each subscriber, and one subscriber uses one spreading code. The method of claim 11,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel group for each subscriber and uses one spreading code group for each subscriber. Device. The method of claim 11,
The direct spread code division multiple access (DS-CDMA) communication system allocates one channel group to each subscriber according to a predetermined time, and spreads the code by using a plurality of subscribers by time-dividing the spreading code group. Used devices. delete The method of claim 11,
The basic code generator,
And assigning a sequence of cyclic shifts of the frank sequence by i * N + j (where i and j are natural numbers) to the j-th subscriber of the i-th group. The method of claim 11,
The spreading code generation unit,
And modulating the output of the random generator and multiplying the assigned basic code to produce a spreading code. The method of claim 11,
The spreading code generation unit,
And repeating N times so that the output of the random generator corresponding to the remainder has the length of the square of N and generating a sequence with the output of the random generator. The method of claim 11,
And a signal transmitter for spreading and transmitting the generated spreading code.

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