KR101340153B1 - Apparatus and method for frequency offset estimation of spread spectrum - Google Patents

Abstract

The present invention relates to a frequency offset recommendation apparatus and method, comprising: a signal generator for generating a spread code based signal having a repetitive structure, receiving a spread code based signal, generating and adding a frequency offset to the spread code based signal, After generating the frequency offset addition signal, the frequency offset generator for converting into a complex number, the frequency offset estimator for estimating the frequency offset from the complex frequency-added additional signal, the actual frequency offset and frequency offset estimator in the spread spectrum signal And an evaluation unit for evaluating the performance of the frequency offset estimator by calculating an average value of squares of the difference between the estimated estimated frequency offsets.
Furthermore, the apparatus for estimating the frequency offset of the spread spectrum signal according to the present invention compares the signal-to-noise ratio and changes the length of the spread-spectrum signal according to the signal-to-noise ratio to improve the estimation range of the frequency offset and the performance of the evaluation unit. It further includes an estimation performance analysis unit.
In addition, the frequency offset estimation method of a spread spectrum signal according to the present invention in step S1 of generating a spread code based signal having a repetitive structure in the signal generator, the spread code based signal received in the frequency offset generator, and spread code based Step S2 of generating and adding a frequency offset to the signal, generating a frequency offset addition signal, and converting the signal to a complex number, and step S3 of estimating the frequency offset added to the frequency offset addition signal converted into a complex number from the frequency offset estimator and the evaluation unit. In step S4 to calculate the average value of the square of the difference between the actual frequency offset of the spread signal and the frequency offset estimated in step S3, and comprises a step S4 for evaluating the performance of the estimator.
Furthermore, in the frequency offset estimation method of a spread spectrum signal according to the present invention, the frequency offset estimation performance analyzer compares the signal-to-noise ratio and changes the length of the spread-spectrum signal according to the signal-to-noise ratio to estimate and estimate the range of frequency offset. It further includes a step S5 to improve negative performance.

Description

Apparatus and method for estimating frequency offset of spread signal {APPARATUS AND METHOD FOR FREQUENCY OFFSET ESTIMATION OF SPREAD SPECTRUM}

The present invention relates to an apparatus and method for frequency offset recommendation, and more particularly, reliability in frequency offset estimation of a spread spectrum signal by applying orthogonal frequency division multiplexing (OFDM) frequency offset estimation technique. The present invention relates to an apparatus and method for estimating a frequency offset of a spread spectrum signal.

Spread Spectrum (SS) is a method of transmitting data using a bandwidth wider than the theoretical bandwidth required for transmitting data. Spread-spread technology is used in a variety of communication systems such as code division multiple access, wireless LAN, and satellite navigation systems because of its strong nature against jamming and multipath interference. In a spread spectrum system, synchronization between a received signal and a signal generated by a receiver should be performed first for demodulation of data.

Time synchronization, phase estimation, and frequency offset estimation should be performed to synchronize the spread spectrum signal. Currently, techniques for time synchronization and phase estimation have been introduced in various ways for synchronization, while techniques for frequency offset estimation are relatively inadequate.

In general, the frequency offset is expressed by normalizing the size of the subcarrier, and divided into the government part and the decimal part according to the size. The integer part causes the shift between subcarrier indices and the fractional part destroys orthogonality between subcarriers. Thus, if the frequency offset is not estimated accurately, the overall performance of the system is degraded. To solve this problem, various methods have been developed and introduced.

The prior art related to the frequency offset estimation apparatus and its frequency offset estimation method of the multi-carrier reception system of Korean Patent Publication No. 10-2003-0040876 using a guard band inserted in the frequency domain to minimize the loss of the subcarrier signal Disclosed are a frequency offset estimating apparatus and a frequency offset estimating method of a multicarrier reception system for estimating frequency offset.

In the prior art, the frequency offset estimating apparatus is calculated by at least one power calculation unit for calculating power for a signal of the guard band inserted in at least one portion of the multiple subcarrier signal in the frequency domain, and at least one power calculation unit And an adder configured to determine a frequency offset using the provided power. Accordingly, by using the guard bands provided at both ends of the multiple subcarrier signals in the frequency domain, the frequency offset can be estimated to easily implement a separate reception system. However, such a prior art has disadvantages such as high power consumption and low reliability when frequency offset estimation. In addition, the efficiency is low because the signal loss is large when estimating the frequency offset.

The present invention has been made to solve the above-mentioned problems, and when estimating the frequency offset of a certain signal, the frequency offset of the spread spectrum signal can be estimated with a simple operation, and the power consumption and signal loss can be minimized. It is an object of the present invention to provide an offset estimation apparatus and method.

In order to achieve the above object, the apparatus for estimating a frequency offset of a spread spectrum signal according to the present invention includes a signal generator for generating a spread code based signal having a repetitive structure, a spread code based signal, and a frequency to the spread code based signal. A frequency offset generator for generating and adding an offset, generating a frequency offset addition signal, and converting it into a complex number, a frequency offset estimator for estimating a frequency offset from the complex number-added frequency offset addition signal, and an actual frequency in the spread spectrum signal And an evaluation unit for evaluating the performance of the frequency offset estimator by calculating an average value of squares of the difference between the estimated frequency offsets estimated by the offset and the frequency offset estimator.

In addition, the frequency offset estimation method of a spread spectrum signal according to the present invention in step S1 of generating a spread code based signal having a repetitive structure in the signal generator, the spread code based signal received in the frequency offset generator, and spread code based Step S2 of generating and adding a frequency offset to the signal, generating a frequency offset addition signal, and converting the signal to a complex number, and step S3 of estimating the frequency offset added to the frequency offset addition signal converted into a complex number from the frequency offset estimator and the evaluation unit. In step S4 to calculate the average value of the square of the difference between the actual frequency offset of the spread signal and the frequency offset estimated in step S3, and comprises a step S4 for evaluating the performance of the estimator.

As described above, the present invention generates a spreading code based signal for frequency estimation of a spread spectrum signal, adds a frequency offset to the spreading code based signal, estimates the frequency offset, and calculates an average square error, thereby making it reliable by simple calculation. High frequency offset estimation is possible. In addition, power consumption and signal loss are low when estimating frequency offset.

1 is a diagram illustrating an apparatus for estimating a frequency offset of a spread spectrum signal according to the present invention.
2 is a diagram illustrating a frequency offset generator according to an embodiment of the present invention.
3 illustrates a frequency offset estimator according to an embodiment of the present invention.
4 is a flowchart illustrating a frequency offset estimation method of a spread spectrum signal according to an embodiment of the present invention.
5 is an MSE graph according to a frequency offset according to an embodiment of the present invention.

Hereinafter, an apparatus and method for estimating a frequency offset of a spread spectrum signal according to the present invention will be described with reference to the accompanying drawings.

1 is a diagram illustrating an apparatus for estimating a frequency offset of a spread spectrum signal according to the present invention. As shown, the apparatus 100 for frequency offset estimation of a spread spectrum signal according to the present invention receives a signal generation unit 101 for generating a spread code based signal having a repetitive structure, a spread code based signal, and spreads a spread code. A frequency offset generation unit 104 for generating and adding a frequency offset to the base signal, generating a frequency offset addition signal, and converting the signal into a complex number, and a frequency offset estimator for estimating the frequency offset from the complex number offset signal. 105) and average values of the squares of the difference between the actual frequency offset in the spread spectrum signal and the frequency offset estimated by the frequency offset estimation unit, and the frequency offset estimation performance of the frequency offset estimation unit according to the reference value and the deviation width of the average values. Evaluation unit 106 to evaluate the.

Furthermore, the present invention compares the signal-to-noise ratio (SNR) and changes the length of the spread spectrum signal according to the SNR to improve the estimation range of the frequency offset and the performance of the evaluation unit 106. The offset estimation performance analyzer 107 may be further included.

According to an embodiment of the present invention, the generation of the frequency offset addition signal and the detection of the frequency offset error may be performed when the Additive White Gaussian Noise (AWGN) channel 103 and the multipath Rician distribution channel 102 exist. Characterized in that made.

Here, the Rician distribution channel 102 is one of channels modeling a multipath communication environment, and a channel of one of the multipath signals is a stronger channel than the signals of the other paths. In AWGN, noise is normally distributed and added to the frequency offset add signal, reducing signal sensitivity. Multipath Rician distribution channel 102 and AWGN channel 103 according to the present invention means the actual communication environment conditions. If the Rician distribution channel 102 and the AWGN channel 103 do not exist, both the transmission and reception signals of the transmitting and receiving end will be the same, and the frequency offset estimation of the frequency offset estimator within the frequency offset estimation range will be made correctly. However, it can be excluded because it is impossible in a real communication environment.

The signal generator 101 generates a spread code based signal for frequency offset estimation under the assumption that both time synchronization and phase estimation are performed during the exaggeration for synchronization of the spread spectrum signal. The spread code based signal is output to the frequency offset generator 104. The frequency offset generator 104 may be described with reference to FIG. 2.

2 is a diagram illustrating a frequency offset generator according to an embodiment of the present invention. As shown, the frequency offset generator 104 receives the spread code based signal generated by the signal generator 101 and divides it into a real part and an imaginary part, and sets a frequency offset value set as a parameter in the real part and the imaginary part. Add. The frequency offset addition signal added with the frequency offset value is converted into a complex number and output.

)은 확산 기반 신호 대역폭에 Normalized된 값을 뜻하며, 정수부와 소수부로 나누어 생각할 수 있다. 정수 주파수 옵셋은 신호를 수신 시, 부반송파의 인덱스를 변화시키고, 소수 주파수 옵셋은 SNR의 감소를 가져오는데, 본 발명에서는 소수 주파수 옵셋 만을 고려하였다.The frequency offset value set by the parameter is equal to the original frequency offset value attached to the spread signal, and the frequency offset (

) Is the normalized value to the spreading-based signal bandwidth, which can be thought of as being divided into integer and fractional parts. The integer frequency offset changes the index of the subcarriers upon receiving the signal, and the fractional frequency offset results in a decrease in the SNR. In the present invention, only the fractional frequency offset is considered.

The present invention includes a complex converter 104a in the frequency offset generator 104 to receive a spread code based signal, divide it into a real part and an imaginary part, and convert the frequency offset addition signal into a complex number. The frequency offset addition signal output from the frequency offset generator 104 is received by the frequency offset estimator 105. The frequency offset estimator 105 may be described with reference to FIG. 3.

3 is a diagram illustrating a frequency offset generator according to an embodiment of the present invention. As shown, the frequency offset estimator 105 receives the frequency offset addition signal received by the frequency offset generator 104 to estimate the frequency offset normalized to the bandwidth of the spread spectrum signal.

The evaluation unit 106 calculates average values of squares of the difference between the actual frequency offset in the spread signal and the frequency offset estimated by the frequency offset estimator, and calculates the frequency of the frequency offset estimator according to the reference value and the deviation width of the average values. Evaluate the offset estimation performance. At this time, it may be numerically '0'. The closer the average is to '0', the better the frequency offset estimation performance. On the other hand, as the average value moves away from '0', it means that the frequency offset estimation performance decreases.

The average values are average values of the squares of the differences between the plurality of actual frequency offsets and the plurality of frequency offsets estimated by the frequency offset estimator. Among the average values, the average value relatively close to '0' means that the frequency offset estimation performance is excellent. The present invention is not limited thereto, and the reference value may be determined according to the target performance of the system.

4 is a flowchart illustrating a frequency offset estimation method of a spread spectrum signal according to an embodiment of the present invention. As shown in FIG. 4, in the method of estimating a frequency offset of a spread spectrum signal, in step S1 of generating a spread code based signal having a repetitive structure in a signal generator, a spread code based signal is received from a frequency offset generator and spread. A step S2 of generating and adding a frequency offset to the sign-based signal, generating a frequency offset addition signal, and converting the signal to a complex number, and step S3 of estimating a frequency offset added to the frequency offset addition signal converted into a complex number by the frequency offset estimator; Step S4 of the evaluation unit calculates the average value of the square number of the difference between the actual frequency offset of the spread signal and the frequency offset estimated in step S3, and evaluates the frequency offset estimation performance of the frequency offset estimator according to the deviation width of the average value It includes.

Furthermore, the method may further include a step S5 of comparing the signal-to-noise ratio in the frequency offset estimation performance analyzer and improving the estimation range of the frequency offset and the performance of the evaluation unit by changing the length of the spread spectrum signal according to the signal-to-noise ratio. .

In an embodiment, in step S1, the signal generator 101 generates a spread code based signal s (n) having a repetitive structure by Equation 1 below. The spread code based signal generated by Equation 1 is output to the frequency offset generator 104 in step S2. Equation 1 expresses that the spread signal is multiplied by the original data signal to generate a spread spectrum signal.

은 확산 부호 기반 신호의 길이,

은

과 서로 소인 정수,

와

는 0부터

사이의 정수를 의미한다. 수학식 1에서 s(n)은 CAZAC(constant amplitude zero autocorrelation) Sequence를 수학적으로 표현한 것이다. Where S (n) is a spread code based signal, n is a sample index,

Is the length of the spread code based signal,

silver

And integers postmarked with each other,

Wow

From 0

Means an integer between. In Equation 1, s (n) is a mathematical expression of the constant amplitude zero autocorrelation (CAZAC) sequence.

In the present invention, the CAZAC sequence is selected as the spread spectrum sequence, and the CAZAC sequence has a constant amplitude in the time and frequency domains, and is spread for synchronization because the autocorrelation value of the remaining points except for time difference 0 is 0. Used as a sequence.

와

는 수열의 인덱스

과 아래의 수학식2와 같은 관계를 갖는다.
At this time, in Equation 1

Wow

Is the index of the sequence

And the relationship as shown in Equation 2 below.

을 36으로 설정하였으며, 이를 각각 4회, 8회 반복하였다. S1단계에서 수학식1과 수학식2를 통해 생성된 확산 부호 기반 신호는 S2단계의 주파수 옵셋 생성부(104)에 출력된다.In the frequency offset estimation method of a spread spectrum signal according to the present invention, in step S1 to specifically implement the frequency offset estimation and to prove the effect

Was set to 36, which was repeated 4 and 8 times, respectively. The spread code based signal generated through the equations (1) and (2) in step S1 is output to the frequency offset generator 104 in step S2.

Equation 2 shows characteristics of the parameters used in the CAZAC sequence of Equation 1. That is, the CAZAC sequence of Equation 1 is generated using numbers satisfying Equation 2.

Step S2 generates a frequency offset addition signal by applying a frequency offset to the spread code based signal received by the frequency offset generator 104 through the AWGN channel and the multipath Rician distribution channel. Step S2 includes receiving a frequency offset addition signal from the complex converter 104a and converting the frequency offset addition signal into a complex number.

In addition, in step S2, the complex code base unit 104a included in the frequency offset generator 104 divides the spread code based signal received from step S1 into a real part and an imaginary part, and sets the parameters by the real part and the imaginary part as parameters. Add an offset value. The frequency offset addition signal to which the frequency offset value is added is converted into a complex number by the complex converter 104a and output.

의 특성을 이용한다. 즉, (a+jb)(cos+jsin)의 방법을 통해 주파수 옵셋을 적용하였으며, 이를 위해 r(n)을 실수부와 허수부로 분리한다.(여기서, r=a+bj)
The spread code based signal received by the frequency offset generator 104 in step S2 is defined by Equation 3 below. Equation 3 below is a complex signal and consists of a real part and an imaginary part. To apply a frequency offset to a signal

Use the characteristics of That is, the frequency offset is applied through the method of (a + jb) (cos + jsin), and r (n) is separated into a real part and an imaginary part for this purpose (r = a + bj).

는 확산 부호 기반 신호의 전력,

는 시간 영역에서 반복 전송된 확산 부호,

는 확산 부호 기반 신호의 대역폭으로 정규화된 주파수 옵셋,

는 평균 0, 분산

을 갖는 AWGN,

은 대역 확산 신호의 길이를 의미한다. Where r (n) is the received signal,

Is the power of the spread code based signal,

Is a spreading code repeatedly transmitted in the time domain,

Is a frequency offset normalized to the bandwidth of a spreading code based signal,

Is an average of 0, variance

AWGN with

Is the length of the spread spectrum signal.

및

로 나타내며, n=0,1,…,N/2-1이다.The frequency offset addition signal output in step S2

And

Where n = 0, 1,... , N / 2-1.

가

을 통해 적용되고, 잡음 w(n)이 신호에 더해진 것을 의미한다. 이때, r(n)은 기저 대역 신호로 간주되며, 시간 및 정수 주파수 옵셋이 맞았다고 가정한다.
Equation 3 is the frequency offset in the CAZAC sequence c (n) having a power of P

end

Is applied through, meaning that the noise w (n) is added to the signal. In this case, r (n) is regarded as a baseband signal and assumes that time and integer frequency offsets are correct.

)를 생성하는 S3-1단계를 포함한다.
Step S3 is a step of estimating the frequency offset value from the frequency offset addition signal received from step S2 through Equation 4 below. In step S3, the constant (

S3-1 step of generating).

이다. 일 예로, 대역 확산 신호의 대역 폭이 2㎒이고, 대역 확산 신호의 길이

이 100이라면, 주파수 옵셋 추정 시 추정 범위는 ± 20㎑이다.
In the step S3, the estimation range when estimating the frequency offset from the frequency offset addition signal using Equation 4 is

to be. For example, the bandwidth of the spread spectrum signal is 2 MHz and the length of the spread spectrum signal

If 100, the estimation range is ± 20 Hz in frequency offset estimation.

로 표현될 수 있으며,

의 각도를 취하게 되면 얻는

을

으로 나누어

를 얻는 것이다.
In Equation 4, r (n) and r (n + N / 2) have the same sequence. Therefore, the frequency offset can be calculated by measuring the phase difference between two signals r (n) and r (n + N / 2) having the same sequence. That is, if r (n + N / 2) is no noise and there is a frequency offset,

Can be expressed as

If you take the angle of

of

Divided by

To get.

In step S4, the evaluation unit 106 calculates an average value by storing the square number of the difference between the frequency offset estimated in step S3 and the actual frequency offset of the spread spectrum signal. Step S4 uses Equation 5 below.

Where MSE is the mean square error and E is the mean operator.

In addition, step S5 compares the signal-to-noise ratio in the frequency offset estimation performance analyzer and changes the length of the spread spectrum signal according to the signal-to-noise ratio, thereby improving the estimation range of the frequency offset and the performance of the evaluation unit. For example, in the MSE performance analysis of Equation 5, the SNRs of 5 kHz and 10 kHz are compared, and the performances are compared by changing the length N of the received signal according to each SNR to 114 and 288, respectively. You can find the estimated range and optimal performance in step S5.

The present invention generates a spreading code based signal when estimating the frequency of a spread spectrum signal, adds a frequency offset to the spreading code based signal, estimates the frequency offset, and calculates an average square error, thereby simplifying the frequency with high reliability. Offset estimation is possible. In addition, power consumption and signal loss are low when estimating frequency offset.

5 is an MSE graph according to a frequency offset according to an embodiment of the present invention. 5 is a simulation result derived by performing a frequency offset estimation method of a spread spectrum signal according to the present invention several times. The simulation conditions consider the cases where the length N of the spread signal is 144, 288. The SNR is 5㏈ and 10㏈. In addition, the K-factor of the Rician distribution channel was set to 8.

≤0.004 및 -0.002≤

≤0.002 정도에서 우수한 성능을 보인다. 그 외의

에서는 성능이 급격히 저하되는 것을 볼 수 있다. 또한, SNR이 20㏈인 상황에서는 N이 144일때, 288일때 각각 MSE는 -0.005≤

≤0.005 및 -0.0025≤

≤0.0025 정도에서 우수한 성능을 보이고 그외의

에서는 성능이 급격히 저하되는 것을 볼 수 있다. When S is 5 ms and N is 144 and 288, MSE is -0.004≤

≤0.004 and -0.002≤

It shows excellent performance at ≤0.002. Other

We can see that the performance drops sharply. In the situation where the SNR is 20 Hz, when N is 144 and 288, the MSE is -0.005≤

≤0.005 and -0.0025≤

Excellent performance at ≤0.0025 degree and others

We can see that the performance drops sharply.

이 주파수 옵셋의 추정 범위의 한계 지점인

에 가까울수록 주파수 옵셋 추정 성능이 잡음의 영향에 더 민감하기 때문이다. 이러한 부분은 SNR이 높아질수록 극복되며, 잡음의 영향이 거의 없는 경우 주파수 옵셋 추정 범위는

과 일치하게 된다. Because it uses angle calculation

The threshold of the estimated range of this frequency offset

The closer to, the more sensitive the frequency offset estimation performance is to noise. This is overcome by higher SNR, and the frequency offset estimation range is less if the noise is not affected.

To match.

The embodiments and the accompanying drawings described in the present specification are merely illustrative of some of the technical ideas included in the present invention. Accordingly, the embodiments disclosed herein are for the purpose of describing rather than limiting the technical spirit of the present invention, and it is apparent that the scope of the technical idea of the present invention is not limited by these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: frequency offset estimation device of the spread spectrum signal
101: signal generator
102: Multipath Rician Distribution Channel
103: AWGN channel
104: frequency offset generator
104a: complex number converter
105: frequency offset estimator
105a: constant generator
106: evaluation unit
107: frequency offset estimation performance analysis unit

Claims (15)

A signal generator for generating a spread code based signal having a repetitive structure;
A frequency offset generator for receiving a spread code based signal, generating and adding a frequency offset to the spread code based signal to generate a frequency offset addition signal, and converting the complex code into a complex number;
A frequency offset estimator for estimating a frequency offset from the complex number-added frequency offset additional signal; And
Computing average values of the squares of the difference between the actual frequency offset in the spread signal and the frequency offset estimated by the frequency offset estimator, and evaluating the frequency offset estimation performance of the frequency offset estimator according to the reference value and the deviation width of the average values. Evaluation department
Frequency offset estimation device of a spread spectrum signal comprising a. The method of claim 1,
The generation of the frequency offset addition signal and the detection of the frequency offset error is performed when the AWGN channel and the multipath Rician distribution channel is present. The method of claim 1, wherein the frequency offset generator,
Dividing a spread code based signal into a real part and an imaginary part, and adding a frequency offset value set as a parameter to the real part and the imaginary part. The method of claim 1, wherein the frequency offset generator
A complex number converting unit for receiving a frequency offset addition signal and converting the signal into a complex number
Frequency offset estimation device of a spread spectrum signal comprising a. The method of claim 1, wherein the frequency offset estimator,
a constant(

And a frequency generator for generating a frequency offset.
(here,

Is the length of the spread spectrum signal) Generating a spread code based signal having a repetitive structure in the signal generator;
Receiving a spread code based signal from the frequency offset generator, generating and adding a frequency offset to the spread code based signal to generate a frequency offset additional signal, and then converting the signal to a complex number;
Step S3 of estimating a frequency offset added to the frequency offset additional signal converted into a complex number by the frequency offset estimating unit;
Step S4 of the evaluation unit calculates the average value of the square number of the difference between the actual frequency offset of the spread signal and the frequency offset estimated in step S3, and evaluates the frequency offset estimation performance of the frequency offset estimator according to the deviation width of the average value
Frequency offset estimation method of a spread spectrum signal comprising a. The method of claim 6, wherein the step S1,
Method for estimating the frequency offset of a spread spectrum signal, characterized in that the signal generator generates a spread code based signal s (n) using Equation 1 below.
(1)

(Where n is the sample index,

Is the length of the spread code based signal,

silver

Are integers with each other,

Wow

Respectively

And

And from 0

Is an integer between The method of claim 7, wherein
Of Equation 1

Wow

The

And a relationship defined by Equation 2 below is established.
(2)

The method of claim 6, wherein the step S2,
A method for estimating frequency offset of a spread spectrum signal using a spread code based signal received through an AWGN channel and a multipath rician distribution channel. The method of claim 6, wherein the step S2,
Step S2-1 of receiving a frequency offset addition signal from the complex converter and converting the frequency offset addition signal into a complex number
Frequency offset estimation method of a spread spectrum signal comprising a. The method of claim 6, wherein the step S2,
A frequency offset estimation method of a spread spectrum signal, characterized in that the frequency offset generator receives a spread code based signal defined by the following equation (3).
(Equation 3)

Where r (n) is the received signal,

Is the power of the spread code based signal,

Is a spreading code repeatedly transmitted in the time domain,

Is a frequency offset normalized to the bandwidth of a spreading code based signal,

Is an average of 0, variance

AWGN with

Is the length of the spread signal) The method of claim 6, wherein the step S2,
The frequency offset generator divides the spread code based signal into a real part and an imaginary part, and adds a frequency offset value set as a parameter to the real part and the imaginary part.

And

And a frequency offset estimation method of a spread spectrum signal. The method of claim 6, wherein the step S3,
Constants in the constant generator

Is generated S3-1
Frequency offset estimation method of a spread spectrum signal comprising a. The method of claim 13, wherein the step S3,
The frequency offset estimation method of the spread spectrum signal, characterized in that the frequency offset estimator estimates the frequency offset value of the frequency offset addition signal by the following equation (4).
(Equation 4)

The method of claim 14, wherein the step S3,
The range of frequency offset estimation is

A frequency offset estimation method of a spread spectrum signal.

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