KR20230009101A - Method and apparatus for adaptive null width control, and base station using same - Google Patents

Abstract

According to an embodiment, an adaptive null width control method is performed by an adaptive null width control device. The adaptive null width control method comprises the following steps of: estimating an error between a beam nulling direction and a jamming signal arrival angle by using Bayesian filter-based arrival angle tracking; and controlling a null width so that a null includes the jamming signal arrival angle based on the estimated error.

Description

Apparatus and method for adaptive null width control and base station using same

The present invention relates to an adaptive null width control apparatus, an adaptive null width control method performed by the apparatus, and a base station to which the adaptive null width control method is applied.

In a communication system using an array antenna, when there is an effect of a jamming signal, anti-jamming beamforming is used to suppress the effect of the jamming signal to prevent communication performance degradation. Anti-jamming beamforming suppresses a jamming signal by assigning a weight to each antenna to generate a null for a direction to be suppressed and steering a beam in a desired direction.

The performance of such anti-jamming beamforming is most effective when the angle of arrival of the jamming signal to be suppressed is accurately known.

However, if there is an error in the angle of arrival of the previously detected jamming signal, the performance of anti-jamming beamforming is rapidly degraded.

Republic of Korea Patent Registration No. 10-2069209, registration date January 16, 2020.

According to an embodiment, an adaptive null width control apparatus and method for estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using a Bayesian filter-based angle of arrival tracking technique and determining a null width based on the estimation result are provided. do.

In addition, according to an embodiment, a base station generating a null having a width determined by reflecting an error between a nulling direction of a beam and an angle of arrival of a jamming signal and steering the beam in a desired direction is provided.

The problem to be solved by the present invention is not limited to those mentioned above, and another problem to be solved that is not mentioned will be clearly understood by those skilled in the art from the description below.

An adaptive null width control method performed by an adaptive null width control apparatus according to a first aspect includes estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking, and the estimated and controlling the null width so that the null includes the angle of arrival of the jamming signal based on the error.

An apparatus for controlling an adaptive null width according to a second aspect includes a communication unit for transmitting and receiving signals, and a processor unit, wherein the processor unit determines a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle-of-arrival tracking through the communication unit. An error between the intervals is estimated, and based on the estimated error, the null width is controlled so that the null includes the angle of arrival of the jamming signal.

A base station according to a third aspect includes: a communication unit that transmits and receives signals with a terminal through a wireless network; a processor unit that determines a nulling direction and a null width of a beam for the terminal; A beam steering unit for steering a beam through a communication unit, wherein the processor unit estimates an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking through the communication unit, and based on the estimated error Thus, a null width is determined so that a null includes an angle of arrival of a jamming signal, and the beam steering unit steers a beam for the terminal through the communication unit according to the determined null width.

A computer readable recording medium storing a computer program according to the fourth aspect, when the computer program is executed by a processor, estimates an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking. and controlling a null width so that the null includes an angle of arrival of the jamming signal based on the estimated error.

A computer program stored in a computer readable recording medium according to a fifth aspect, when the computer program is executed by a processor, estimates an error between a beam nulling direction and a jamming signal arrival angle using Bayesian filter-based angle of arrival tracking. and controlling a null width so that the null includes an angle of arrival of the jamming signal based on the estimated error.

According to an embodiment of the present invention, an error between a nulling direction of a beam and an angle of arrival of a jamming signal is estimated using a Bayesian filter-based angle-of-arrival tracking technique, and a null width is determined based on the estimation result. In addition, according to an embodiment, a null is generated with a width determined by reflecting an error between a nulling direction of a beam and an angle of arrival of a jamming signal, and the beam is steered in a desired direction.

Accordingly, since the angle of arrival of the jamming signal can be accurately tracked and an error in the angle of arrival is adaptively responded to, the performance of anti-jamming beamforming is improved.

1 is a schematic diagram of a mobile communication system for explaining jamming signal arrival angle tracking and adaptive null width control according to an embodiment of the present invention.
2 is a configuration diagram of the base station shown in FIG. 1;
3 is a state diagram for explaining the operation principle of a particle filter as an example of a Bayesian filter, showing a process of generating random particles and determining a weight.
4 is a schematic diagram illustrating null width expansion using virtual interferer generation.
5 is a graph showing changes in null width and depth according to the number of virtual interferers.
6 is a flowchart illustrating an adaptive null width control apparatus and an adaptive null width control method performed by a base station according to an embodiment of the present invention.
7 is a graph showing the null width determined using the estimated angle of arrival error approximated by particles, the actual angle of arrival error, and the estimation error over time.
8 is a graph comparing performance of a technique of estimating the angle of arrival of a jamming signal using only a particle filter and generating nulls in a corresponding direction and a technique of applying adaptive null width control.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the embodiments described below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims.

The terms used in this specification will be briefly described, and the present invention will be described in detail.

The terms used in the present invention have been selected from general terms that are currently widely used as much as possible while considering the functions in the present invention, but these may vary depending on the intention of a person skilled in the art or precedent, the emergence of new technologies, and the like. In addition, in a specific case, there is also a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the invention. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, not simply the name of the term.

In the entire specification, when a part is said to 'include' a certain component, it means that it may further include other components, rather than excluding other components, unless otherwise stated.

In addition, the term 'unit' used in the specification means software or a hardware component such as FPGA or ASIC, and 'unit' performs certain roles. However, 'wealth' is not limited to software or hardware. 'Unit' may be configured to reside in an addressable storage medium and may be configured to reproduce one or more processors. Thus, as an example, 'unit' refers to components such as software components, object-oriented software components, class components and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. Functions provided within components and 'parts' may be combined into a smaller number of elements and 'parts' or further separated into additional elements and 'parts'.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted.

Anti-jamming beamforming performed by a base station including an adaptive null width control apparatus according to an embodiment of the present invention exhibits the best performance when the angle of arrival of a jamming signal to be suppressed is accurately known, and When there is an error in the angle of arrival of the jamming signal, the performance of anti-jamming beamforming is rapidly degraded. In order to prevent performance degradation due to the angle of arrival estimation error, a method of extending the null width so that the null includes the jamming signal may be considered.

However, when the null width extension technique is used, if the null width is excessively expanded, it becomes vulnerable to noise. Therefore, the null width to be expanded must be appropriately determined in order to minimize the effects of noise and jamming signals.

When jamming signals are suppressed using beamforming with a null width extension technique, if the extended null of the beam radiation pattern does not include the angle of arrival of the jamming signal, the influence of the jamming signal increases, increasing the signal-to-noise ratio. Interference-plus-noise-ratio (SINR) performance is poor. On the other hand, if the null width is excessively extended to include the angle of arrival of the jamming signal, it becomes very vulnerable to noise. A discrepancy between the nulling direction and the angle of arrival of the jamming signal mostly occurs in the process of tracking the motion of the jamming signal source.

According to an embodiment of the present invention, an adaptive null width control technique for tracking the angle of arrival of a jamming signal and controlling the null width is provided to prevent performance degradation when a discrepancy between the nulling direction of a beam and the angle of arrival of a jamming signal occurs. . Adaptive null width control adjusts the null width so that the null includes the jamming signal arrival angle according to the difference between the nulling direction and the jamming signal arrival angle, thereby preventing performance degradation caused by the jamming signal arrival angle deviating from the nulling direction.

According to an embodiment of the present invention, an error between a nulling direction of a beam and an angle of arrival of a jamming signal is estimated using a Bayesian filter-based angle of arrival tracking technique to determine an appropriate null width. For example, the error in estimating the angle of arrival of the jamming signal can be obtained from the standard deviation of particles.

According to an embodiment of the present invention, after estimating an error between a beam nulling direction and an angle of arrival of a jamming signal, an appropriate null width may be determined and controlled. As a method of extending the null width, a method of assuming that a plurality of virtual interference exists around the angle of arrival of the jamming signal at regular angular intervals and generating a null for the angle of arrival of the assumed virtual interference may be used.

1 is a schematic diagram of a mobile communication system 100 for explaining jamming signal arrival angle tracking and adaptive null width control according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of a base station 110 shown in FIG. 1 to be. This is an example using a Bayesian filter-based angle-of-arrival tracking technique, multipath signals other than straight paths are ignored to help the explanation, and a method of adjusting the number of virtual interferences is applied to control the null width.

Bayesian filter based jamming signal arrival angle tracking and adaptive null width control are periodically performed every time slot. When it is assumed that a pilot signal is applied during communication between the base station 110 and the terminal 120, the period of time slots is the same as the period between pilot signals.

The base station 110 updates a nulling direction with a Bayesian filter and estimates a channel gain in order to estimate an angle of arrival of a jamming signal that changes in real time to correspond to the moving jammer 130 . Here, as the Bayesian filter, a Kalman filter, an extended Kalman filter, a particle filter, or the like can be used (S1).

In addition, when the angle estimation error generated in the process of tracking the angle of arrival of the jamming signal increases and the null is generated in the wrong direction (S2), the base station 110 widens the null width through adaptive null width control (S3) to cause the angle error. SINR performance degradation is prevented. Then, when the angle estimation error is reduced, the base station 110 narrows the null width again through adaptive null width control to reduce the effect of noise.

As illustrated in FIG. 2 , the base station 110 performing adaptive null width control according to an embodiment of the present invention includes a communication unit 111, a processor unit 112, and a beam steering unit 113. Of course, the example of FIG. 2 shows only parts necessary for explanation of the present invention among various configurations of the base station 110 . Here, except for the beam steering unit 113, it may be referred to as an adaptive null width control device according to an embodiment of the present invention. That is, the adaptive null width control apparatus according to an embodiment of the present invention includes a communication unit 111 and a processor unit 112, and may perform the adaptive null width control method according to an embodiment of the present invention. .

The communication unit 111 of the base station 110 transmits and receives signals with the terminal 120 through a wireless network.

The processor unit 112 determines a nulling direction and a null width of a beam with respect to the terminal 120 . Functions and processing of the processor unit 112 will be described again below.

The beam steering unit 113 steers the beam through the communication unit 111 according to the determined null width of the processor unit 112 with respect to the terminal 120 .

In the base station 110 including this configuration, the processor unit 112 estimates an error between the nulling direction of the beam and the angle of arrival of the jamming signal using Bayesian filter-based angle of arrival tracking through the communication unit 111, and estimates the error according to the estimated error. Based on this, the null width is determined so that the null includes the angle of arrival of the jamming signal.

Here, the processor unit 112 tracks the angle of arrival of the jamming signal and adaptive null width according to a predetermined pilot signal period when a jamming signal exists in the pilot signal received through the communication unit 111 before estimating the error. The cycle of control can be set. After controlling the null width, reception of the next pilot signal may be waited for.

를 고정한 후 중심 널링 방향 주위에

의 간격으로 가정할 가상 간섭원의 개수

를 조정하여 널 폭을 제어할 수 있다. 또는, 프로세서부(112)는 가상 간섭원 개수

를 고정한 후 중심 널링 방향 주위에

개의 가상 간섭원을 배치할 인접 가상 간섭원 간의 간격

을 조정하여 널 폭을 제어할 수도 있다.For example, the processor unit 112 may set the adjacent virtual interferer interval

around the center knurling direction after fixing

The number of virtual interferers to be assumed with an interval of

You can control the null width by adjusting Alternatively, the processor unit 112 determines the number of virtual interferers

around the center knurling direction after fixing

Interval between adjacent virtual interferers to place the virtual interferers

You can also control the null width by adjusting .

Hereinafter, an adaptive null width control apparatus included in the mobile communication system 100 and an adaptive null width control method performed by the base station 110 according to an embodiment of the present invention will be described in detail.

번째 타임 슬롯에 해당하는 상태 벡터

와 확률론적 진화 모델은 다음과 같이 나타낼 수 있다.In tracking the angle of arrival of the jamming signal, a channel gain that changes for each time slot and an angle of arrival of the jamming signal are estimated, and a nulling direction is determined for the estimated angle of arrival. The state vector consists of variables to be estimated, which correspond to the channel gain and the angle of arrival of the jamming signal. Additionally, a stochastic evolutionary model representing the change of state over time must be established.

State vector corresponding to the th time slot

and the stochastic evolution model can be expressed as:

,

,

는 각각 단말기와 재머 간 채널 이득의 실수부와 허수부 및 재밍 신호의 도래각을 의미하며,

는 상태 변화 행렬을 나타내고,

는 가우시안 분포를 따르는 프로세스 잡음을 나타낸다.here

,

,

Means the real and imaginary parts of the channel gain between the terminal and the jammer and the angle of arrival of the jamming signal, respectively,

denotes the state change matrix,

denotes the process noise following a Gaussian distribution.

3 is a state diagram for explaining the operating principle of a particle filter as an example of a Bayesian filter, showing a process of generating random particles and determining a weight.

와 같이 재밍 신호의 채널 이득 및 도래각 정보를 포함한다. 도 3에서

,

,

는 각각

번째 파티클의 채널 이득 실수부와 허수부 및 재밍 신호의 도래각을 의미하며,

,

는 실제 수신 신호에서 받고자 하는 신호를 뺀 신호와

번째 파티클로 재구성한 재밍 신호 추정값이다. 여기서 받고자 하는 신호는 CSI-RS 혹은 SRS와 같은 파일럿 신호이다.

,

의 값이 비슷할수록 가능도가 높아지며, 파티클의 가능도에 비례한 가중치가 증가한다. 재밍 신호의 채널 이득 및 도래각 추정값은 가중치가 부여된 파티클들의 평균과 같다.The particle filter-based jamming signal arrival angle tracking generates random particles following a stochastic evolution model as shown in FIG. 3 and assigns a weight to each particle. each particle

It includes the channel gain and angle of arrival information of the jamming signal as in in Figure 3

,

,

are respectively

It means the real part and the imaginary part of the channel gain of the th particle and the angle of arrival of the jamming signal,

,

is the signal obtained by subtracting the signal to be received from the actual received signal.

It is a jamming signal estimation value reconstructed with the th particle. A signal to be received here is a pilot signal such as CSI-RS or SRS.

,

The more similar the value of is, the higher the probability is, and the weight in proportion to the probability of the particle increases. The channel gain and angle-of-arrival estimate of the jamming signal is equal to the average of the weighted particles.

The technology for tracking the angle of arrival of the real-time jamming signal and determining the direction of null generation is updated every time slot, and the terminal 120 and the base station 110 transmit and receive a predetermined pilot signal in the corresponding time slot. Tracking is performed using the remainder after subtracting the expected received signal between the base station and the terminal from the actual received signal. Formulating this, it can be expressed as:

는 각각 파티클 필터 기반 재밍 신호 추적에 사용할 measurement이고,

는 실제 수신 신호이며,

는 기지국과 단말기 간 수신 파일럿 신호이다.here

are the measurements to be used for particle filter-based jamming signal tracking, respectively,

is the actual received signal,

Is a received pilot signal between the base station and the terminal.

개의 무작위 파티클을 생성하고 각 파티클에 가능도에 따른 가중치를 다음과 같이 부여한다.Following a stochastic evolutionary model at every time slot

It creates 2 random particles and assigns a weight according to the probability to each particle as follows.

는

번째 파티클이고,

은

번째 파티클의 가중치이며,

는

에 해당하는 재밍 신호의 채널 이득 및 도래각을 가정했을 때의 예상 측정(measurement)과

간 가능도를 의미한다. 모든 가중치의 합은 1이 되어야 하며,

번째 타임 슬롯에 해당하는 상태 벡터의 추정값

는 다음과 같이 나타낼 수 있다.here

Is

is the second particle,

silver

is the weight of the th particle,

Is

Expected measurement (measurement) assuming the channel gain and angle of arrival of the jamming signal corresponding to

means the possibility of interfering. The sum of all weights must be 1,

estimate of the state vector corresponding to the th time slot

can be expressed as:

추정 후

에 포함된 재밍 신호 추정 도래각

에 대해 널 생성 방향을

로 결정한다.

after estimation

The estimated angle of arrival of the jamming signal included in

the direction of null generation for

to decide

The adaptive null width control performed by the processor unit 112 serves to widen or reduce the null width according to an angle estimation error, and is executed every time slot. When using the particle filter-based jamming signal arrival angle tracking technique, the angle estimation error is approximated by the variance of the particles. The null width is extended by assuming virtual interferers at regular intervals around the central nulling direction, and can be expressed as a product of the number of virtual interferers and the virtual interferer spacing.

를 고정한 후 중심 널링 방향 주위에

의 간격으로 가정할 가상 간섭원의 개수

를 조정하여 널 폭을 제어할 수 있다.According to an embodiment of the present invention, the processor unit 112 of the base station 110 determines the adjacent virtual interferer interval.

around the center knurling direction after fixing

The number of virtual interferers to be assumed with an interval of

You can control the null width by adjusting

를 고정한 후 중심 널링 방향 주위에

개의 가상 간섭원을 배치할 인접 가상 간섭원 간의 간격

을 조정하여 널 폭을 제어할 수 있다.Alternatively, the processor unit 112 of the base station 110 determines the number of virtual interferers.

around the center knurling direction after fixing

Interval between adjacent virtual interferers to place the virtual interferers

You can control the null width by adjusting

4 is a schematic diagram illustrating null width expansion using virtual interferer generation.

를 이용해 가상 간섭 신호를 포함한 새로운 공분산 행렬

를 생성하며 이는 다음과 같이 나타낼 수 있다.The null width extension technique using the virtual interference used when the null width control is performed can be represented as shown in FIG. 4 . After assuming that there is a virtual interference signal source that transmits the same signal as the original signal including the original nulling direction at a regular interval around the original nulling direction, nulls are generated for directions including the original and virtual interference directions. Covariance matrix of the signal to compute beamforming vectors that produce nulls for multiple directions

A new covariance matrix including the virtual interference signal using

, which can be expressed as:

는 가상 간섭원 개수이고,

는

번째 가상 간섭원의 각도이며,

는 각도

에 대한 조향벡터이고,

는 행렬의 켤레전치이며,

는 인접한 두 가상 간섭원 간 간격을 의미하고,

는 다음과 같이 나타낼 수 있다.here,

is the number of virtual interferers,

Is

is the angle of the th virtual interference source,

is the angle

is the steering vector for

is the conjugate transpose of the matrix,

is the distance between two adjacent virtual interferers,

can be expressed as:

는 신호의 스냅샷을 의미하며,

는 배열안테나로 수신되는 수신 신호의

번째 스냅샷을 의미한다. 생성한

를 이용해 가상 간섭원 방향들에 대해 널을 생성하면서 바라보고자 하는 방향

로 빔을 조향한다. 이 경우 빔포밍 벡터

는 다음과 같이 나타낼 수 있다.here,

denotes a snapshot of the signal,

of the received signal received by the array antenna

the second snapshot. created

The direction to look at while generating nulls for virtual interferer directions using

Steer the beam with In this case, the beamforming vector

can be expressed as:

5 is a graph showing changes in null width and depth according to the number of virtual interferers.

를 이용해 일정 간격 방향에 대해 널을 생성할 경우 도 5와 같이 널 폭 및 널 깊이가 증가한다. 널을 깊게 생성함으로써 억제하고자 하는 재밍 신호 또는 간섭 신호를 더욱 억제할 수 있으며 널 폭을 증가시킴으로써 억제할 신호가 널에서 벗어나 SINR 성능이 저하되는 것을 방지할 수 있다.

When nulls are generated in the direction of a constant interval using , the null width and the null depth increase as shown in FIG. 5 . By creating deep nulls, jamming signals or interference signals to be suppressed can be further suppressed, and by increasing the null width, it is possible to prevent signals to be suppressed from deteriorating SINR performance.

는 가상 간섭원 개수

와 인접한 가상 간섭원 간 각도 간격

의 곱으로 나타낼 수 있으며, 파티클 필터 기반 도래각 추적 이용 시 각도 추정 오차

를 이용해 다음과 같이 나타낼 수 있다.The optimal null width is a value that is as similar as possible to the difference between the angle of arrival of the jamming signal estimated through particle filter-based angle of arrival tracking technology and the angle estimation error in order to prevent the direction of the jamming signal from deviating from the null when an error in estimation of the angle of arrival of the jamming signal occurs. to decide board width

is the number of virtual interferers

Angular spacing between the virtual interferers adjacent to

It can be expressed as a product of , and angle estimation error when using particle filter-based angle of arrival tracking

can be expressed using

은 올림을 의미한다.

는 다음과 같이 나타낼 수 있으며, 도래각 추적 방식에 따라 추정 방법이 다를 수 있다.here,

means round up.

can be expressed as follows, and the estimation method may be different depending on the angle of arrival tracking method.

는 총 파티클 수이고,

는

번째 타임 슬롯에서

번째 파티클의 가중치이며,

는

번째 타임 슬롯에서

번째 파티클의 재밍 신호 도래각이고,

는

번째 타임 슬롯에서의 도래각 추정값을 의미한다.here,

is the total number of particles,

Is

in the second timeslot

is the weight of the th particle,

Is

in the second timeslot

is the angle of arrival of the jamming signal of the th particle,

Is

It means the estimated value of the angle of arrival in the th time slot.

6 is a flowchart illustrating an adaptive null width control apparatus and an adaptive null width control method performed by a base station according to an embodiment of the present invention.

Referring to FIG. 6 , the processor unit 112 of the base station 110 checks whether a jamming signal exists in the pilot signal received by the communication unit 111 (S610).

When a jamming signal exists, the processor unit 112 sets a period for tracking the angle of arrival of the jamming signal and controlling the adaptive null width according to a predetermined pilot signal period (S620).

Subsequently, the processor unit 112 estimates an error between the nulling direction of the beam and the angle of arrival of the jamming signal using particle filter-based angle-of-arrival tracking (S630 and S640).

Then, the processor unit 112 controls the null width so that the null includes the angle of arrival of the jamming signal based on the estimated error (S650 and S660).

After the step of controlling the null width, the processor unit 112 waits for reception of the next pilot signal (S670).

On the other hand, if it is confirmed in step S610 that the pilot signal does not exist in the jamming signal, the processor unit 112 controls the beam steering unit 113 to steer the beam toward the terminal, as in a general control process (S680).

As described above, after confirming that a jamming signal exists, the base station 110 tracks the jamming signal, estimates an angle of arrival estimation error, determines and controls a null generation direction and a null width. When there is no jamming signal, the beam is steered in the communication direction and maintained until the next pilot signal is received.

를 이용한 널 폭 결정 시, 널 폭

를 다음의 수학식을 이용해 결정할 수 있다.Error in angle of arrival approximated by particle filter

When determining the board width using

can be determined using the following equation.

는 인접한 가상 간섭원 간 간격이고,

는 가상 간섭원 개수로서 정수이다.here

is the spacing between adjacent virtual interferers,

is the number of virtual interferers and is an integer.

When the adaptive null width control is used, the jamming signal does not leave the null and is sufficiently suppressed even in the case of an angle estimation error that suddenly occurs, thereby ensuring stable signal reception.

In order to confirm the effect of tracking the angle of arrival of a jamming signal and controlling the adaptive null width according to an embodiment of the present invention, an experimental environment in which a highly mobile jammer and its signal exist in communication between a stationary base station and a terminal at a fixed location is implemented. So, the simulation was conducted.

의 배수가 되도록 올림한 값만큼 널 폭이 결정이 되며 또한 가상 간섭원의 개수 조절을 통해 결정된 널 폭 값만큼 널을 확장한다. 도 7을 통해 널 폭이 실시간으로 도래각 추정 오차에 따라 제어됨을 확인할 수 있다. 추가적으로 파티클로 근사한 도래각 추정 오차 값이 실제 도래각 추정 오차와 흡사한 결과를 가짐을 확인할 수 있다.7 is a graph showing a null width determined using an estimation error of an angle of arrival approximated by a particle, an error of an actual angle of arrival, and an estimation error over time, and is a simulation result for confirming correlation between each graph. If the angle of arrival estimation error occurs, the estimation error

The null width is determined by a value rounded up to be a multiple of , and the null is extended by the null width value determined by adjusting the number of virtual interferers. It can be confirmed through FIG. 7 that the null width is controlled according to the angle of arrival estimation error in real time. Additionally, it can be confirmed that the angle of arrival estimation error value approximated by particles has a result similar to the actual angle of arrival estimation error.

8 is a graph comparing performance of a technique of estimating the angle of arrival of a jamming signal using only a particle filter and generating nulls in a corresponding direction and a technique of applying adaptive null width control. The left side of FIG. 8 shows the accuracy of estimating the angle of arrival according to the time slot when each technology is applied, and is the root mean square error (RMSE) analysis result of the estimated angle. Although the signal angle of arrival estimation accuracy is similar, the adaptive null width control technique has slightly better performance and can cope with the continuously occurring angle of arrival estimation error through the adaptive null width control.

The right side of FIG. 8 shows SINR performance, which is an index of signal reception stability when each technology is applied according to time slots. Let's compare SINR performance when adaptive null width control technology is not applied and when adaptive null width control technology is applied and conventional beamforming is performed in which nulls are not generated and steering in the direction of the arrival angle of the base station and the terminal. Over time, the existing nulling direction control technology is inferior to the performance of the beamforming technology that does not track the arrival angle of the jamming signal and does not generate nulls, whereas the adaptive null width control technology can guarantee relatively high SINR performance. can know that

On the other hand, each step included in the adaptive null width control method and the anti-jamming beamforming method of the base station according to the above-described embodiment is a computer readable program recording a computer program including instructions for performing these steps. It can be implemented in a recording medium.

As described above, according to an embodiment of the present invention, an error between a nulling direction of a beam and an angle of arrival of a jamming signal is estimated using a Bayesian filter-based angle of arrival tracking technique, and a null width is determined based on the estimation result. In addition, according to an embodiment, a null is generated with a width determined by reflecting an error between a nulling direction of a beam and an angle of arrival of a jamming signal, and the beam is steered in a desired direction.

Accordingly, since the angle of arrival of the jamming signal can be accurately tracked and an error in the angle of arrival is adaptively responded to, the performance of anti-jamming beamforming is improved.

Combinations of each step in each flowchart attached to the present invention may be performed by computer program instructions. Since these computer program instructions may be loaded into a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment function as described in each step of the flowchart. create a means to do them. These computer program instructions can also be stored on a computer usable or computer readable medium that can be directed to a computer or other programmable data processing equipment to implement functions in a particular way, so that the computer usable or computer readable It is also possible that the instructions stored on the recording medium produce an article of manufacture containing instruction means for performing the functions described in each step of the flowchart. The computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. Instructions for performing the processing equipment may also provide steps for executing the functions described at each step in the flowchart.

Further, each step may represent a module, segment or portion of code that includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative embodiments it is possible for the functions mentioned in the steps to occur out of order. For example, two steps shown in succession may in fact be performed substantially concurrently, or the steps may sometimes be performed in reverse order depending on the function in question.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential qualities of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: mobile communication system
110: base station
111: communication department
112: processor unit
113: beam steering unit
120: terminal
130: jammer

Claims (14)

An adaptive null width control method performed by an adaptive null width control apparatus,
Estimating an error between a beam nulling direction and a jamming signal arrival angle using Bayesian filter-based angle-of-arrival tracking;
Controlling a null width so that a null includes an angle of arrival of a jamming signal based on the estimated error.
Adaptive null width control method. According to claim 1,
Prior to the step of estimating the error, if a jamming signal exists in the received pilot signal, setting a period for tracking the angle of arrival of the jamming signal and controlling the adaptive null width according to a predetermined period of the pilot signal;
After the step of controlling the null width, further comprising waiting for reception of a next pilot signal
Adaptive null width control method. According to claim 1,
In the step of estimating the error, when tracking the angle of arrival based on the particle filter as the Bayesian filter, the angle of arrival is calculated using the remainder after subtracting the expected received signal between the base station and the terminal from the actual received signal using the following equation for each time slot track,

(here

is the measurement target to be used for particle filter-based jamming signal tracking,

is the actual received signal,

is the received pilot signal between the base station and the terminal.)
Following a stochastic evolutionary model at every time slot

Random particles are generated, and each generated particle is given a weight according to the probability as shown in the following equation,

(here

Is

is the second particle,

silver

is the weight of the th particle,

Is

Assuming the channel gain and angle of arrival of the jamming signal corresponding to

It means the likelihood of the interval, and the sum of all weights must be 1,)

estimate of the state vector corresponding to the th time slot

can be expressed as the following equation

Adaptive null width control method. According to claim 1,
In the step of estimating the error, the error (

) is estimated using the following equation,

(here,

is the total number of particles,

Is

in the second timeslot

is the weight of the th particle,

Is

in the second timeslot

is the angle of arrival of the jamming signal of the th particle,

Is

It means the estimated value of the angle of arrival in the th time slot.)
Adaptive null width control method. According to claim 1,
In the step of controlling the null width,
Adjacent Virtual Interferer Spacing

around the center knurling direction after fixing

The number of virtual interferers to be assumed with an interval of

to control the knurl width by adjusting
Adaptive null width control method. According to claim 1,
In the step of controlling the null width,
Number of virtual interferers

around the center knurling direction after fixing

Interval between adjacent virtual interferers to place the virtual interferers

to control the knurl width by adjusting
Adaptive null width control method. According to claim 1,
In the step of controlling the null width, the null width

To determine using the equation below,

(here,

is the angle of arrival error approximated through the particle filter,

is the spacing between adjacent virtual interferers,

is the number of virtual interferers, which is an integer.
Adaptive null width control method. A communication unit for transmitting and receiving signals;
Including a processor unit,
The processor unit,
Estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking through the communication unit, and controlling a null width so that the null includes the angle of arrival of the jamming signal based on the estimated error
Adaptive board width control. According to claim 8,
The processor unit,
Before estimating the error, if a jamming signal exists in the pilot signal received through the communication unit, a period for tracking the angle of arrival of the jamming signal and controlling the adaptive null width is set according to a predetermined pilot signal period, and the null After controlling the width, waiting to receive the next pilot signal
Adaptive board width control. According to claim 8,
The processor unit,
Adjacent Virtual Interferer Spacing

around the center knurling direction after fixing

The number of virtual interferers to be assumed with an interval of

to control the knurl width by adjusting
Adaptive board width control. According to claim 8,
The processor unit,
Number of virtual interferers

around the center knurling direction after fixing

Interval between adjacent virtual interferers to place the virtual interferers

to control the knurl width by adjusting
Adaptive board width control. A communication unit for transmitting and receiving signals through a terminal and a wireless network;
A processor unit for determining a nulling direction and a null width of a beam with respect to the terminal;
A beam steering unit for steering a beam through the communication unit with respect to the terminal according to the determination of the processor unit;
The processor unit,
Estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking through the communication unit, and based on the estimated error, determining a null width such that the null includes the angle of arrival of the jamming signal,
The beam steering unit,
Steering a beam through the communication unit with respect to the terminal according to the determined null width
base station. A computer-readable recording medium storing a computer program,
When the computer program is executed by a processor,
Estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking, and controlling a null width so that the null includes the angle of arrival of the jamming signal based on the estimated error A computer-readable recording medium comprising instructions for causing the processor to perform a method. As a computer program stored on a computer-readable recording medium,
When the computer program is executed by a processor,
Estimating an error between a nulling direction of a beam and an angle of arrival of a jamming signal using Bayesian filter-based angle of arrival tracking, and controlling a null width so that the null includes the angle of arrival of the jamming signal based on the estimated error A computer program comprising instructions for causing the processor to perform a method.

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