KR101138589B1 - Method and apparatus for transmitting sensor information - Google Patents

Abstract

The present invention relates to a sensor information transmission method and apparatus for confidentially transmitting information detected by a plurality of sensors in a distributed detection system to a convergence center using a signal processing technique of a transmitter, and according to an embodiment of the present invention. According to the sensor information transmission method, complete security can be maintained only by the design of the transmission signal of the sensor, it is possible to construct a new security system with a lower complexity than the existing cryptography-based security system, as well as a wireless sensor network requiring low power and light weight technology. It can be used as an appropriate technology in such fields.

Description

Method and apparatus for transmitting sensor information {Method and apparatus for transmitting sensor information}

The present invention relates to a sensor information transmission method and apparatus for confidentially transmitting information detected by a plurality of sensors in a distributed detection system to a convergence center using a signal processing technique of a transmitter.

The distributed detection system refers to a technology in which a plurality of sensors form a network to detect a change in a target and transmit this information to a fusion center to detect the final state of the object. Since the state of the target object is finally determined based on the detection information of the sensor, the greater the number of sensors, the higher the accuracy of the final detection result. However, in a general wireless communication environment where resources are limited, a large number of sensors provide a cause such as a reduction in data rate and processing speed due to resource allocation problems, and thus an appropriate system configuration is necessary. In addition, it is very important to configure the system with low power / light weight technology because it is not easy to replace the battery of the sensor in the case of a sensor network installed in a place where a person is physically inaccessible. One of the conventional studies is a protocol method of a distributed detection system named TBMA (Type-Based Multiple Access). This technology includes a process in which each sensor of the network transmits some information about a target to a convergence center through a multiple access channel, and has bandwidth and power efficiency.

The features of distributed detection systems, including resource allocation, deployment issues, etc. described above present many difficulties when constructing a security system. In particular, the distributed detection system increases the communication path in proportion to the number of sensors, so the number of communication paths to be protected from eavesdropping threats is much higher than the number of paths formed in an environment such as a cellular network or a Wi-Fi network. . However, the distributed detection system has much limited resources (power, bandwidth, etc.) than the above-mentioned communication environment, and thus there are many difficulties in constructing a powerful communication and security system.

In the conventional distributed detection security system, a security system based on a cryptographic algorithm is mainstream. In most studies, relatively low complexity symmetric encryption key technology has been considered as a suitable technique for distributed detection systems, rather than asymmetric encryption key technology for managing the encryption keys of many sensors. However, symmetric encryption key technology requires periodic encryption key update in preparation for loss and exposure of encryption key, and encryption key distribution algorithm required at this time has problems such as high computational complexity and reuse of encryption key. This problem is a big obstacle in constructing a strong security system in the case of a sensor network with a lot of resource usage restrictions.

In addition to cryptography-based security systems, physical layer security systems using channel coding have recently attracted much attention. However, the previous studies related to this have only theoretically proved that channel codes provide perfect security, and there have been no reports on channel codes that can implement them.

Each sensor in the network observes a common goal and transmits the result to the convergence center via a wireless communication channel. The fusion center uses the information received from the sensor to perform the binary hypothesis determination problem for the target. Although data confidentiality is currently required in many wireless sensor network applications, it is vulnerable to security due to the fact that wireless communication channels are open to anyone. Conventional approaches have been proposed based on cryptography, but cryptography-based approaches are hampering the application of wireless center networks to sensors with limited resources to perform secret key distribution problems and cryptographic algorithms.

The present invention includes a security technique required when multiple sensors deliver information obtained through distributed detection to a convergence center. An object of the present invention is to provide a method and apparatus for transmitting sensor information capable of minimizing information leakage to an eavesdropper while excluding cryptography.

In particular, it aims to achieve data confidentiality by taking advantage of the fact that the main channel between the sensor and the legitimate fusion center and the eavesdropping channel between the sensor and the legitimate fusion center are random and independent of the conventional cryptography based approach.

In order to solve the above technical problem, a method for transmitting information detected from a plurality of sensors in a wireless sensor network according to an embodiment of the present invention receives a pilot signal from a legitimate convergence center, by using the received pilot signal Estimating a channel with the legal fusion center; Comparing the channel estimation result with predetermined threshold values and selecting a sensor operation mode according to the comparison result; And transmitting the information detected from the sensor according to the selected operation mode.

The sensor mode of operation comprises a first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And a second mode for transmitting a signal in a direction that interferes with the binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center.

Compensating for the phase of the channel in advance using the channel state information when the sensor operation mode is the first mode.

The method may further include quantizing the information detected by the sensor when the sensor operation mode is the second mode, and transforming the quantized value by using a shearing function.

According to another aspect of the present invention, there is provided a method of transmitting sensor information, the method comprising: quantizing a value measured by each sensor; Comparing the pilot signal from the legitimate fusion center with predetermined threshold values to select an operating mode of each sensor; And transmitting the information to the legitimate fusion center according to the selected operation mode using the normalized orthogonal signal corresponding to the quantized value.

The mode of operation of the sensor includes a first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And a second mode for transmitting a signal in a direction that interferes with the binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center.

Selecting a normal orthogonal signal based on the quantized value when the operation mode of the sensor is a first mode; And compensating for the phase of the channel using the channel state information.

Transforming the quantized value using a shear history function when the operation mode of the sensor is a second mode; And selecting a normal orthogonal signal based on the modified quantization value.

The sensor information transmitting method may further include generating a first random number Rs when an amplitude of the channel gain instantaneous value of the sensor is greater than a first parameter ts; Comparing a first activation threshold value qs (m) selected according to the first random number and the quantized value; And when the first random number is greater than the first activation threshold, selecting an operation mode of the sensor as a first mode.

The sensor information transmitting method may further include generating a second random number Rw when an amplitude of the channel gain instantaneous value of the sensor is smaller than a second parameter tw; Comparing the second random number with a second activation threshold value qw (m) selected according to the quantized value; And selecting the operation mode of the sensor as the second mode when the second random number is larger than the second activation threshold.

According to another aspect of the present invention, there is provided a sensor information transmitting apparatus comprising: a quantizer configured to quantize a value measured by each sensor; A mode selector for selecting an operation mode of each sensor by comparing the pilot signal from the legitimate fusion center with predetermined threshold values; And a transmitter for transmitting the quantized value to the legitimate fusion center using a normal orthogonal signal corresponding to one-to-one according to the selected operation mode.

The sensor information transmitting device may further include a channel estimator configured to receive a pilot signal from the legal fusion center and estimate a channel with the legal fusion center using the received pilot signal.

The operating mode includes a first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And a second mode for transmitting a signal in a direction that interferes with the binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center.

A normal orthogonal signal selecting unit which selects a normal orthogonal signal based on the quantized value when the operation mode of the sensor is a first mode; And a phase compensator configured to compensate the phase of the channel by using the channel state information.

A quantization value transformation unit for transforming the quantized value using a shear yarn function when the operation mode of the sensor is a second mode; And a normal orthogonal signal selector for selecting a normal orthogonal signal based on the modified quantization value.

The legal fusion center is characterized in solving a binary hypothesis determination problem for a target based on the information of the transmitted sensor.

Since the sensor information transmission method according to an embodiment of the present invention can maintain perfect security only by designing the transmission signal of the sensor, a new security system having a lower complexity than the existing cryptography-based security system can be configured. In particular, it can be used as an appropriate technology in fields such as wireless sensor networks requiring low power and light weight technology.

1 is a diagram illustrating a system structure according to an embodiment of the present invention.
2 is a flowchart illustrating a selection of an operation mode of a sensor.
3 is a diagram illustrating a transmission structure of a sensor.
FIG. 4 is a diagram illustrating an example of comparing a probability density function of a signal received at an eavesdropping convergence center to a target binary state when acquiring perfect security; FIG.
5 is a diagram illustrating a receiver structure of a fusion center.
FIG. 6 is a diagram illustrating a detection error probability comparison in a legitimate convergence center for a case where there is a disturbance signal for perfect security and a case where there is no disturbance signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts may be omitted so as not to distract from the gist of the present invention.

In addition, terms and words used in the following description and claims should not be construed to be limited to ordinary or dictionary meanings, but are to be construed in a manner consistent with the technical idea of the present invention As well as the concept.

The present invention proposes a method and apparatus for transmitting sensor information that can be avoided from eavesdropping threat when a plurality of sensors detect a state of a target in a distributed detection system and transmit the result to a convergence center.

1 is a diagram illustrating a structure of a distributed detection security transmission system according to an exemplary embodiment of the present invention. In FIG. 1, the plurality of sensors 111 to 116 constituting the network observe a common target 121, quantize the measured values, select a transmission signal through a series of processes, and then select a multiple access fading channel. It transmits to the legitimate convergence center 101 through. At this time, the transmitted signal is also transmitted to the wiretap convergence center 102 due to the broadcast nature of the wireless channel. In this case, when the distance between the convergence center is longer than the wavelength of the transmission signal, the channel between the sensor and the legitimate convergence center and the sensor between the tapping and convergence center may be considered to undergo independent fading. The present invention proposes an apparatus and method for transmitting and receiving sensors that satisfy the following requirements in the above-described environment. First, the eavesdropping convergence center should not be able to obtain information about the state of the target from the received signal. Second, legitimate convergence centers must provide acceptable detection performance from received signals.

In order to satisfy the above requirements, the present invention proposes a method in which each sensor operates in the following three modes by using channel state information between the sensor and the legal convergence center. That is, the first mode includes a state for assisting the decision making of the legal convergence center, the second mode includes a state for preventing the hypothesis determination of the wiretap convergence center, and the standby mode does not participate in the transmission. After receiving the pilot signal transmitted by the legitimate convergence center, the sensor estimates the channel state and compares the known threshold values (t _s , t _w ) with the channel estimation value, such as the pilot signal, to determine the mode of the sensor. To perform.

2 is a flowchart illustrating a method of determining a mode of a sensor. Each sensor may perform channel estimation 201 using the pilot signal received from the legitimate convergence center, and as a result, may obtain the instantaneous value of the channel gain.

과 비교한다. 발생한 난수 Rw가 q_w(m)보다 큰 경우는 제2 모드를 선택하고 나머지 경우에는 대기 모드를 선택한다. In the next process, the amplitude value of the channel gain instantaneous value is compared (203), and the following different process is performed according to the result. If the amplitude of the channel gain instantaneous value of the sensor is greater than t _s , the sensor generates (205) a random number represented by Rs (0 ≦ Rs ≦ 1) and activates a preselected activation according to the quantized value m obtained through quantization at the sensor. It is compared with the threshold value _{q s (m) (0≤q s} (m) ≤1). When the generated random number Rs is larger than q _s (m), the first mode is selected, and in the other cases, the standby mode is selected. Similarly, if the value of the sensor channel gain instantaneous amplitude is less than t _w sensor preselected activation threshold value according to the generated 207 random number m and the quantization level is represented by R _w (0≤R _w ≤1)

Compare with When the generated random number Rw is larger than q _w (m), the second mode is selected, and in the other cases, the standby mode is selected.

를 이용해 적법 융합센터에 전달된다. 예를 들어, 양자화된 값이 m일 때, 센서는 대응되는 정규직교함수 y_m를 전송한다. 이때

은 각각 M개의 양자화 값에 대응되는 정규 직교함수 집합이다. 다음 과정으로 도 2 및 상기에서 설명된 모드 선택과정(303)을 수행하여 센서의 동작 모드를 선택한다. 제1 모드에 해당하는 센서들은 양자화된 값을 기준으로 해당 정규직교함수를 송신 신호할 신호로 선택(307)한다. 제2 모드에 해당하는 센서들은 양자화된 값을 b(m)으로 표기되는 양자화된 값의 집합을 정의역과 치역으로 갖는 전 단사 함수의 결과를 통해 변형(305)된 값을 이용하여 해당 정규직교함수

를 송신(307)한다. 예를 들어, 양자화 값 1이고 전 단사 함수의 결과가 b(1)=3일 때, 센서가 송신할 신호로 선택하는 정규직교함수는

이다. 상기의 과정으로 선택된 신호는 다시 센서의 모드에 따라 제1 모드인 경우에는 채널 상태 정보로부터 추정한 채널의 위상을 미리 보상(309)하여 융합센터로 송신하며, 제2 모드인 경우에는 위상 보상 없이 선택된 신호를 송신한다. 3 illustrates a transmission structure of a sensor proposed in the present invention, and describes a transmission method for each mode. The value measured by each sensor is converted into one of values from 1 to M through the quantization process 301. Quantized values are orthogonal to one-to-one correspondences

Is delivered to the due process convergence center. For example, when the quantized value is m, the sensor transmits the corresponding orthonormal function y _m . At this time

Is a set of orthonormal functions corresponding to M quantization values, respectively. Next, the operation mode of the sensor is selected by performing the mode selection process 303 described above with reference to FIG. 2. The sensors corresponding to the first mode select 307 a corresponding orthogonal function as a signal to be transmitted based on the quantized value. Sensors corresponding to the second mode use the normal orthogonal function by using the transformed value 305 through the result of the total injector function having the set of quantized values represented by b (m) in the domain and the domain.

Transmit (307). For example, if the quantization value is 1 and the result of the total injective function is b (1) = 3, the normal orthogonal function that the sensor selects as the signal to transmit is

to be. The signal selected by the above process is again compensated (309) the phase of the channel estimated from the channel state information in the first mode according to the sensor mode, and transmitted to the fusion center, and in the second mode without phase compensation Send the selected signal.

In the sensor signal transmission method according to an embodiment of the present invention, the above-described design parameters t _s , t _w , b (m), q _s = q _s (0) q _s (1) L q _s (M -1) ^T , q _w = q _w (0) q _w (1) L q _w (M-1) By appropriately adjusting ^T , the signal from the eavesdropping signal, regardless of the receiver and the allocated resources, Information about the target state can be made unavailable. To this end, in an embodiment of the present invention parameters such that the target state _{(q 0 / q 1) (} q 0 / q 1) the tapped signal conditional probability density function (Conditional probability density function) of the tapping fusion center for the independent variable Design it. This design goal is a necessary and sufficient condition to achieve perfect secrecy as defined by the Information Theory, thus ensuring that the eavesdropping convergence center cannot obtain information about the target state. The choice of design parameters can be deduced from the following procedure.

First, the signals received at the eavesdropping convergence center are modeled by the normal orthogonal functions corresponding to the quantized values calculated through the multi-access fading channel, respectively. Can be.

In the above equation, S _s and S _W are sets of sensors corresponding to the first mode and the second mode, respectively, and X _i is a quantized value obtained by the i th sensor. H _i is the channel gain corresponding to the signal transmitted from the i-th sensor, and n is the noise.

In this case, the convergence center may express the received signal with respect to the quantized value using a matched filter 503 composed of a normal orthogonal function. The received value for the quantized value m can be expressed by Equation 2 below.

Here, 1 (A) has a value of 1 when the conditional statement is true, and 0 otherwise.

는 도청 융합센터에서 취득한 센서의 송신정보에 대한 충분 통계치(Sufficient statistics)이다. 본 발명의 일 실시 예에서는 완벽보안을 달성하기 위한 설계 매개변수를 선택함에

에 대한 충분 통계치의 조건부 확률밀도함수

가

에 독립이 되도록 설정하여 완벽보안을 달성한다. 이를 위해 우선적으로 충분 통계치의 조건부 확률 밀도함수를 유도한다. At this time, the received signal re-expressed with respect to the quantized value

Is sufficient statistics on the transmission information of the sensor obtained from the wiretap convergence center. In one embodiment of the present invention to select a design parameter to achieve perfect security

Conditional Probability Density Function of Sufficient Statistics for

end

Achieving complete security by setting to be independent of To do this, we first derive a conditional probability density function of sufficient statistics.

로 표기한다. 추가적으로 N_m ^s 와 N_m ^w은 각각

을 전송한 제1 모드의 센서 개수와 제2 모드의 센서 개수라고 표기하고, N_m ^s 와 N_m ^w 의 합을

한다. 이때, 충분 통계치 T^E에 대한 조건부 확률밀도함수는 다음의 수학식 3으로 표현된다.Probability mass function of the quantized values for the binary state of the target

It is written as. In addition, N _m ^s and N _m ^w are respectively

Denotes the number of sensors in the first mode and the number of sensors in the second mode, and sums N _m ^s and N _m ^w .

do. At this time, the conditional probability density function for the sufficient statistical value T ^E is expressed by the following equation (3).

이다.here,

to be.

In Equation 3, the sufficient statistics T ^E have a conditional independent characteristic when K is given, and thus Equation 3 may be represented again as in Equation 4 below.

은 다음 수학식 5로 분해할 수 있다.In Equation 4,

Can be decomposed to the following equation (5).

이며, 마지막 단계는 N^S 와 N^W 가 서로 독립적인 사건이라는 사실과 L_S 와 L_W 의 정의로부터 유추할 수 있다.In Equation 5,

The final step can be derived from the fact that N ^S and N ^W are independent events _and the definition of L _S and L _W.

Each part constituting Equation 5 may be represented by Equations 6 to 8.

이다.here,

to be.

이다.here,

to be.

이다.here,

to be.

By using this conditional probability density function for T ^E can be expressed by the following equation (9).

이다.here,

to be.

을 위한 첫 번째 충분 조건은 다음 수학식 10으로 표현된다.Perfect security from Equation 9

The first sufficient condition for is expressed by the following equation (10).

는

에 관계없이 동일한 값을 가지며, 이때 T^E 에 대한 조건부 확률 밀도함수는 다음 수학식 11로 다시 표현된다.From the above conditions,

Is

Irrespective of the same value, the conditional probability density function for T ^E is represented by Equation 11 below.

The last step in Equation 11 can be inferred from the binomial theorem.

From Equation 11, a second sufficient condition for perfect security can be obtained, and is represented by Equation 12 below.

이다.here,

to be.

을 설정하면 완벽보안을 달성할 수 있다.Therefore, design parameters satisfying the above equations 10 and 12,

You can achieve perfect security by setting.

Next, an embodiment of a parameter design process satisfying the above condition will be described. The process of setting each variable may be different according to the intention of the designer, and the embodiments proposed by the present invention are as follows.

1) Set the value of t _s

에 대하여 수학식 10을 만족하는

를 설정2) given

Satisfying Equation 10 with respect to

Set

3) Set the preinjection function b (m) that satisfies the following equation (13).

그리고 b(m)에 대하여 다음 수학식 14를 만족하는

를 설정4) given in the design above

And b (m) satisfies the following equation (14).

Set

이다.here,

to be.

그리고,

에 대해서 상기 수학식 15를 만족하는

를 설정5) given in the above design

And,

Satisfying Equation 15 with respect to

Set

4 illustrates an embodiment of comparing a conditional probability density function of a signal received at an eavesdropping convergence center for obtaining perfect security to a binary state of a target. The number N of sensors constituting the network is 20, the number M of quantization levels is 2, and the probability weight function for the quantization level is expressed by the following equation (16).

에 대하여 다음 수학식 17을 만족하도록 선택한다.Next, the threshold known at the legal fusion center is the amplitude of the channel gain instantaneous value of the sensor.

Is selected to satisfy the following equation (17).

으로 선택하며, 나머지 매개변수

와

는 완벽보안을 얻기 위한 수식 과정으로부터 유추하여 선택한다. 마지막으로 제2 모드-모드의 센서에 대해서 수행하는 양자화된 값 변형 과정은

으로 선택한다. 그 결과, 도 4로부터 도청 융합센터에서 수신한 신호의 조건부 확률밀도함수가 목표의 이진 상태에 관계없이 동일한 분포를 따르는 것을 확인할 수 있다.The vector form of the activation threshold used in the mode selection process described with reference to FIG.

, The remaining parameters

Wow

Is selected by inference from the mathematical process to obtain perfect security. Finally, the quantized value transformation process performed on the second mode-mode sensor

Select with. As a result, it can be seen from FIG. 4 that the conditional probability density function of the signal received at the wiretap fusion center follows the same distribution regardless of the target binary state.

The legitimate convergence center basically receives a form in which the signals transmitted from the sensor and the noise are added together, and solves the problem of determining the binary hypothesis for the target. Since the receiver structure of the legal convergence center can be variously selected according to the resources and the situation allocated to the system, detailed description thereof will be omitted. 5 is a diagram illustrating a receiver structure of a legal convergence center. The received signal passes through a matched filter 503 composed of normal orthogonal functions corresponding to the quantized value to obtain the received value for each quantized value. In the next process, the combiner 505 converts the output of the matched filter into a vector form, and solves the binary hypothesis determination problem for the target by using the conditional probability density function for the output of the matched filter in the maximum likelihood detector 507. As mentioned above, the maximum likelihood detection process may be simplified when it is difficult to obtain the conditional probability density function of the output of the matched filter or the received signal according to the situation of the system and the designer.

FIG. 6 shows detection performance in due process and tapping convergence centers obtained using a simplified maximum likelihood detection process using Gaussian approximation. The parameters considered in this embodiment are as follows. First, the conditional probability weight function for the quantized value obtained by the sensor is expressed by the following equation (18).

에 대해서 다음의 수학식 19를 만족하도록 선택한다.Next, the threshold known from the legal convergence center is the amplitude of the instantaneous channel gain of the sensor.

Is selected to satisfy the following equation (19).

으로 선택하며, 나머지 매개 변수

와

는 상기 도청 융합센터에 대한 실시 예에서와 마찬가지로 완벽보안을 얻기 위한 수식 과정으로부터 유추하여 선택한다. 마지막으로 제2 모드의 센서에 대해서 수행하는 양자화된 값 변형 과정은

으로 선택한다. 도 6에서 별 모양 실선은 도청 융합센터에서의 검출오류확률을 도시하며, 십자 모양 실선과 점선은 각각 완벽보안을 얻기 위해 방해신호를 생성할 때에 대한 적법 융합센터에서의 검출오류확률을 실험을 통해 얻은 값과 분석을 통해 얻은 상한을 도시한 것이다. 마지막으로 원 모양의 실선과 점선은 각각 완벽보안을 고려하지 않고 방해신호, 즉 제2 모드의 센서를 추가적으로 동작시키지 않을 때에 대한 적법 융합센터에서의 검출오류확률의 실험값과 상한을 도시한다. 도 6에서 도시한 비교로부터 완벽보안을 위해 발생하는 적법 융합센터에서의 검출성능 열화 정도가 적은 것을 확인할 수 있다. The vector form of the activation threshold used in the mode selection process introduced in FIG.

Select the remaining parameters

Wow

In the same manner as in the embodiment of the wiretap convergence center, it is selected by inferring from a mathematical process for obtaining perfect security. Finally, the quantized value transformation process performed on the sensor in the second mode

Select with. In FIG. 6, the star solid line shows the probability of detection error in the wiretap fusion center, and the cross-shaped solid line and the dotted line respectively show the probability of detection error in the legitimate convergence center when generating a disturbance signal for perfect security. The values obtained and the upper limits obtained from the analysis are shown. Finally, the solid line and the dotted line respectively show the experimental value and the upper limit of the detection error probability in the legal fusion center for the interference signal, that is, when the sensor of the second mode is not additionally operated without considering the perfect security. It can be seen from the comparison shown in FIG. 6 that the degree of detection performance deterioration in the legal convergence center that is generated for perfect security is small.

An apparatus according to the present invention may include a processor, a memory for storing and executing program data, a permanent storage such as a disk drive, a communication port for communicating with an external device, a user interface such as a touch panel, a key, Devices, and the like. Methods implemented by software modules or algorithms may be stored on a computer readable recording medium as computer readable codes or program instructions executable on the processor. Here, the computer-readable recording medium may be a magnetic storage medium such as a read-only memory (ROM), a random-access memory (RAM), a floppy disk, a hard disk, ), And a DVD (Digital Versatile Disc). The computer-readable recording medium may be distributed over networked computer systems so that computer readable code can be stored and executed in a distributed manner. The medium is readable by a computer, stored in a memory, and executable on a processor.

All documents including publications, patent applications, patents, etc. cited in the present invention can be incorporated into the present invention in the same manner as each cited document individually and concretely, .

In order to facilitate understanding of the present invention, reference will be made to the preferred embodiments shown in the drawings, and specific terminology is used to describe the embodiments of the present invention. However, the present invention is not limited to the specific terminology, Lt; / RTI > may include all elements commonly conceivable by those skilled in the art.

The invention can be represented by functional block configurations and various processing steps. Such functional blocks may be implemented in various numbers of hardware or / and software configurations that perform particular functions. For example, the present invention relates to integrated circuit configurations such as memory, processing, logic, look-up table, etc., which may execute various functions by the control of one or more microprocessors or other control devices. It can be adopted. Similar to the components of the present invention that may be implemented with software programming or software components, the present invention may be implemented as a combination of C, C ++, and C ++, including various algorithms implemented with data structures, processes, routines, , Java (Java), assembler, and the like. The functional aspects may be implemented with an algorithm running on one or more processors. In addition, the present invention may employ the prior art for electronic environment setting, signal processing, and / or data processing. Terms such as "mechanism", "element", "means" and "configuration" can be used widely and are not limited to mechanical and physical configurations. The term may include the meaning of a series of routines of software in conjunction with a processor or the like.

The specific acts described in the present invention are, by way of example, not intended to limit the scope of the invention in any way. For brevity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted. Also, the connections or connecting members of the lines between the components shown in the figures are illustrative of functional connections and / or physical or circuit connections, which may be replaced or additionally provided by a variety of functional connections, physical Connection, or circuit connections. Also, unless explicitly mentioned, such as " essential ", " importantly ", etc., it may not be a necessary component for application of the present invention.

In the specification (particularly in the claims) of the present invention, the use of the term “above” and similar indicating terms may correspond to both singular and plural. In addition, in the present invention, when the range is described, it includes the invention to which the individual values belonging to the range are applied (if not stated to the contrary), and each individual value constituting the range is described in the detailed description of the invention. Same as Finally, if there is no explicit order or contrary to the steps constituting the method according to the invention, the steps may be performed in a suitable order. The present invention is not necessarily limited to the description order of the above steps. The use of all examples or exemplary terms (eg, etc.) in the present invention is merely for the purpose of describing the present invention in detail, and the scope of the present invention is limited by the examples or exemplary terms unless defined by the claims. It doesn't happen. In addition, one of ordinary skill in the art appreciates that various modifications, combinations and changes can be made depending on design conditions and factors within the scope of the appended claims or equivalents thereof.

Claims (17)

A method of transmitting information detected from a plurality of sensors in a wireless sensor network,
Receiving a pilot signal from a legal fusion center and estimating a channel with the legal fusion center using the received pilot signal;
Comparing the channel estimation result with predetermined threshold values and selecting a sensor operation mode according to the comparison result; And
Transmitting information sensed by the sensor according to the selected operation mode. The method of claim 1,
The sensor operation mode,
A first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And
And a second mode of transmitting a signal in a direction that interferes with a binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center. The method of claim 2,
When the sensor operation mode is the first mode,
And compensating for the phase of the channel in advance by using the channel state information. The method of claim 2,
When the sensor operation mode is the second mode,
And quantizing the information sensed by the sensor, and transforming the quantized value by using a shearing function. Quantizing the values measured at each sensor;
Comparing the pilot signal from the legitimate fusion center with predetermined threshold values to select an operating mode of each sensor; And
And transmitting the quantized value to the legitimate convergence center according to the selected operation mode using a one-to-one corresponding normal orthogonal signal. The method of claim 5, wherein
The operation mode of the sensor,
A first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And
And a second mode of transmitting a signal in a direction that interferes with a binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center. The method according to claim 6,
When the operation mode of the sensor is the first mode,
Selecting a normal orthogonal signal based on the quantized value; And
And compensating for the phase of the channel using the channel state information. The method according to claim 6,
When the operation mode of the sensor is the second mode,
Transforming the quantized value using a shear yarn function; And
And selecting a normal orthogonal signal based on the modified quantization value. The method of claim 7, wherein
Generating a first random number Rs when the amplitude of the channel gain instantaneous value of the sensor is greater than a first parameter ts;
Comparing a first activation threshold value qs (m) selected according to the first random number and the quantized value; And
And selecting the operating mode of the sensor as the first mode when the first random number is larger than the first activation threshold. The method of claim 8,
Generating a second random number Rw when the amplitude of the channel gain instantaneous value of the sensor is less than a second parameter tw;
Comparing the second random number with a second activation threshold value qw (m) selected according to the quantized value; And
And selecting the operation mode of the sensor as the second mode when the second random number is larger than the second activation threshold. A recording medium having recorded thereon a program for executing a method according to any one of claims 1 to 10 on a computer. A quantizer for quantizing the values measured by each sensor;
A mode selector for selecting an operation mode of each sensor by comparing the pilot signal from the legitimate fusion center with predetermined threshold values; And
And a transmitter for transmitting the quantized value to the legitimate convergence center according to the selected operation mode using a one-to-one corresponding orthogonal signal. The method of claim 12,
And a channel estimating unit for receiving a pilot signal from the legal fusion center and estimating a channel with the legal fusion center using the received pilot signal. The method of claim 12,
The operation mode,
A first mode of transmitting a signal in a direction to assist in determining a binary hypothesis of the legal fusion center; And
And a second mode for transmitting a signal in a direction that obstructs the binary hypothesis determination of the wiretap fusion center corresponding to the legal fusion center. 15. The method of claim 14,
When the operation mode of the sensor is the first mode,
A normal orthogonal signal selector which selects a normal orthogonal signal based on the quantized value; And
And a phase compensator for compensating for the phase of the channel using the channel state information. 15. The method of claim 14,
When the operation mode of the sensor is the second mode,
A quantization value transformation unit that transforms the quantized value using a shear yarn function; And
And a normal orthogonal signal selector for selecting a normal orthogonal signal based on the modified quantization value. 17. The method of claim 16,
The legal convergence center,
And a binary hypothesis determination problem for a target based on the transmitted sensor information.

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