KR102481853B1 - Apparatus and method for analysis of channel characteristics - Google Patents

Abstract

The channel characteristic analysis device calculates a power delay profile from channel data measured by rotating the antenna 360 degrees at a predetermined angle, calculates a power angle delay spectrum from the channel data, and an antenna pattern having a beam width value input through a user input device. Create a filter corresponding to And, after reconstructing the power delay profile by using the filter as a window from the power angle delay spectrum and calculating a power angle spectrum within the range of the window, at least one of the reconstructed power delay profile and the power angle spectrum Calculate channel parameters.

Description

Channel characteristic analysis device and method {APPARATUS AND METHOD FOR ANALYSIS OF CHANNEL CHARACTERISTICS}

The present invention relates to an apparatus and method for analyzing channel characteristics, and more specifically, from channel measurement data using a single horn antenna in an ultra-high frequency band, path loss for omnidirectional or arbitrary orientations, delay and incidence angle characteristics of multipath components, etc. It relates to a channel characteristic analysis device and method capable of analyzing or reprocessing radio channel characteristics.

In accordance with the recent explosive increase in mobile smart devices and services, competition to secure frequency resources for 5G and B5G next-generation mobile communications is becoming increasingly fierce. As a representative example, in 5G mobile communication, various radio wave characteristics analysis studies have been conducted to apply the millimeter wave band from 6GHz to 80GHz to the mobile communication field. Various studies are being attempted to utilize ultra-wideband frequency resources of several GHz or more in ultra-high frequencies of 100 GHz or more to overcome the acceptance limit due to resources and transmission capacity. However, the ultra-high frequency band of millimeter wave or higher generally has a very short propagation distance and strong linearity compared to the existing cellular band below 6 GHz, and has very diverse characteristics depending on the medium such as reflection and diffraction depending on the surrounding radio environment, making it a mobile communication environment. There are many difficulties in cell radius and coverage design for application to . Therefore, research is needed to analyze very accurate channel characteristics through actual measurement and data collection of wireless channels in various radio wave environments and to develop more accurate statistical channel models.

In general, in order to perform wireless channel characteristic analysis and modeling, data is firstly collected through a wireless channel measuring device (Channel Sounder) in an actual field environment, and path loss, delay and incident angle of multipath components are analyzed through analysis of the collected data. A process of extracting various statistical channel characteristic parameters such as characteristics is performed.

An apparatus for measuring a radio channel in a low frequency band is configured in such a way as to collect actual measurement data of a channel using a plurality of receiving antennas. However, in the ultra-high frequency band of several tens of GHz or more, a plurality of RF (Radio Frequency) modules and antennas are required to configure a radio channel measurement apparatus using a plurality of antennas, and a plurality of receiving antennas must be placed in all directions. It is very costly and it is very difficult to calibrate characteristics between multiple RF modules. Therefore, an apparatus for measuring a radio channel in an ultra-high frequency band configures an apparatus for measuring a channel while rotating an omni-directional antenna or a horn antenna for reception having an arbitrary beam width at an arbitrary angle, Collect actual data from the field and analyze the collected data.

However, the conventional analysis technique of analyzing the collected measurement data using an omni antenna or a device for performing channel measurement while rotating an omni antenna or a single receiving horn antenna with a beam width of several tens of degrees at an arbitrary angle has a disadvantage in that the analysis results are very limited. there is Specifically, in the case of measurement data using an omni-antenna, it is possible to obtain relatively omnidirectional path loss characteristics in the horizontal direction due to the characteristics of the omni-antenna (antenna pattern), but path loss at any azimuth angle or all altitudes It is difficult to analyze the propagation characteristics considering the elevation angle. That is, although it is possible to grasp the path loss for a 360-degree horizontal azimuth angle, it is limited to analyze the path loss in all directions considering all vertical elevation angles. When used, it is difficult to analyze the angle of incidence of multipath components other than pathloss. In addition, when data is collected and analyzed by rotating a directional horn antenna having a beam width of several tens of degrees at an arbitrary angle, the precision of the conventional analysis device is limited in proportion to the rotation angle of the horn antenna. As an example, when a horn antenna with a beam width of 20 degrees is rotated in all directions at intervals of 10 degrees, the analysis accuracy for the incident angle (azimuth and elevation angles of multipath components) of the radio wave is limited to 10 degrees. In addition, in the case of collecting measurement data by rotating the rotation angle of the directional horn antenna at very small angles (for example, 1 degree) intervals in the measurement step for high-precision channel characteristic analysis in the number of units, omnidirectional angles such as azimuth and elevation angles Since all must be rotated, measurement time is very long.

The problem to be solved by the present invention is to analyze various radio channel characteristics such as path loss, delay and incidence angle characteristics of multipath components with high precision from data measured while rotating a single receiving horn antenna with a beam width of several tens of degrees at an arbitrary angle, or It is to provide a channel characteristic analysis device and method capable of performing reprocessing.

According to one embodiment of the present invention, a method for analyzing channel characteristics in a channel characteristic analysis device is provided. The channel characteristic analysis method includes calculating a power delay profile from channel data measured by rotating the antenna 360 degrees at a predetermined angle, calculating a power angle delay spectrum from the channel data, and having a beam width value input through a user input device. Generating a filter corresponding to an antenna pattern, reconstructing the power delay profile by using the filter as a window from the power angle delay spectrum, calculating a power angle spectrum within the range of the window, and reconstructing the power angle spectrum. and calculating at least one channel parameter from a power delay profile and the power angle spectrum.

According to an embodiment of the present invention, it is possible to easily extract path loss and various channel characteristic parameters from data measured by rotating a horn antenna having an arbitrary beam width at an arbitrary angle, and collect data according to rotation of a certain angle. However, channel characteristic parameters can be easily extracted through omnidirectional synthesis.

In addition, when a wireless device has an antenna with an arbitrary beam width and wants to analyze channel characteristics according to the beam width in advance, it can be easily provided and used for various simulations for future wireless transmission technology development.

1 is a block diagram of an apparatus for analyzing channel characteristics according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of PADS results calculated by the PADS synthesizer shown in FIG. 1 .
FIG. 3 is a diagram illustrating an example of generating a filter according to a beam width value in the beam width filter generator shown in FIG. 1 .
FIG. 4 is a diagram showing an example of reconfiguring a PADS into a PDP by setting an arbitrary window in the window PDP reconfigurator shown in FIG. 1 .
5 and 6 are diagrams showing an example of a channel parameter for delay spread and a channel parameter for angular spread, respectively, according to an antenna beam width calculated according to an embodiment of the present invention.
7 is a flowchart illustrating a channel characteristic analysis method according to an embodiment of the present invention.
8 is a schematic diagram of a channel characteristic analysis device according to another embodiment of the present invention.

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. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification and claims, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Now, a channel characteristic analysis apparatus and method according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a block diagram of an apparatus for analyzing channel characteristics according to an embodiment of the present invention.

Referring to FIG. 1, the channel characteristic analysis apparatus 100 includes a Power Delay Profile (PDP) generator 110, a Power Angle and Delay Spectrum (PADS) synthesizer 120, and a window PDP reconstruction. A generator 130, a beamwidth filter generator 140, a window power angle spectrum (PAS) reconstructor 150, and a channel parameter calculator 160 are included.

The channel characteristic analysis device 100 is connected to the wireless channel measuring device 200 and receives measurement data collected from the wireless channel measuring device 200 in the form of a channel impulse response (CIR).

The radio channel measuring device 200 is equipped with a horn antenna 300 having an arbitrary beam width, and mechanically rotates the horn antenna 300 horizontally at an azimuth angle of 360 degrees relative to the forward direction. Or, measure the radio channel while vertically rotating the elevation angle (elevation) up and down 90 degrees. The radio channel measurement device 200 provides measurement data collected through radio channel measurement to the channel characteristic analysis device 100 in the form of CIR.

In an embodiment of the present invention, when CIR data measured through omnidirectional rotation of the horn antenna 300 up, down, left, and right is provided to the channel characteristic analyzer 100, the channel characteristic analyzer 100 can perform omnidirectional and arbitrary angles. A process for calculating high-precision channel characteristic parameters according to various beam widths, such as path loss in and delay and angle of arrival characteristics of multipath components present on the radio, will be described. .

In order to facilitate the description of the embodiment of the present invention, when measurement data is obtained by rotating the horn antenna 300 having an arbitrary beam width by 360 degrees at i-degree intervals in the horizontal direction (Azimuth direction), rotation A process of calculating channel parameters for each angle is described. After that, the difference in the case of rotation in the vertical direction is separately described.

The PDP generator 110 converts input CIR data into PDPs for each rotation angle of the horn antenna 300 as shown in Equation 1.

In Equation 1, h _i (τ) represents the CIR obtained in the i-th rotation stage of the horn antenna 300. N represents the total number of rotations of the horn antenna 300. That is, when the horn antenna 300 rotates 360 degrees at intervals of 10 degrees, N = 36, and a total of 36 h _i (τ) from i = 1 to 36 are obtained. τ represents a delay on the time axis.

)]을 계산하며, PADS(τ,

)는 수학식 2와 같이 계산될 수 있다. The PADS synthesizer 120 uses the input CIR data to generate a power angular delay spectrum [PADS(τ,

)], PADS(τ,

) can be calculated as in Equation 2.

는 도래각(angle of arrival, AoA)을 나타낸다. N은 혼 안테나(300)의 회전 수를 나타내고, Ω는 무선 채널 측정 장치(200)에서 사용한 혼 안테나(300)의 방사패턴 데이터(radiation pattern of the horn antenna)를 나타낸다. (.)^*는 컨주게이트(complex conjugate)를 나타내고, h_i(τ)는 혼 안테나(300)의 i번째 회전 단계에서 획득한 CIR을 나타낸다. In Equation 2, τ represents the delay,

denotes the angle of arrival (AoA). N represents the number of rotations of the horn antenna 300, and Ω represents the radiation pattern of the horn antenna used in the radio channel measuring device 200. (.) ^* denotes a complex conjugate, and h _i (τ) denotes a CIR obtained in the ith rotation step of the horn antenna 300.

FIG. 2 is a diagram showing an example of PADS results calculated by the PADS synthesizer shown in FIG. 1 .

)는 도 2와 같이 나타나게 된다. When the PADS synthesizer 120 calculates the PADS based on Equation 2 from the CIR obtained through rotation of the horn antenna 300, the horn antenna 300 is rotated from -180 to 180 degrees according to the rotation angle in the horizontal direction. PADS (τ, the distribution of received power for each delay

) will appear as shown in FIG.

Referring again to FIG. 1 , the window PDP reconfigurator 130 reconstructs PDP, which is channel characteristic information according to an arbitrary beam width, using a window generated by the beam width filter generator 140 .

At this time, the beamwidth filter generator 140 generates a filter corresponding to an antenna pattern having a corresponding beamwidth according to a beamwidth value input by a user through the user input unit 400 . The beamwidth filter generator 140 can be used as a tool for analyzing channel characteristic parameters according to an antenna pattern of a beamwidth input by a user even when channel measurement is performed using the horn antenna 300 having any beamwidth. .

FIG. 3 is a diagram illustrating an example of generating a filter according to a beam width value in the beam width filter generator shown in FIG. 1 .

For example, as shown in FIG. 3, the type of filter generated according to the beam width in the beam width filter generator 140 may be defined as a rectangular filter or an arbitrary 3dB Half Power Beam Width (HPBW) filter. Alternatively, a filter using a radiation pattern of an actual antenna may be created.

A PDP may be reconstructed according to a filter corresponding to an antenna pattern having a beam width input by a user using the beam width filter generator 140 .

The window PDP reconfigurator 130 may reconstruct the PDP using an antenna pattern having an arbitrary beam width generated by the beam width filter generator 140 or an actual antenna pattern as shown in Equation 3. That is, the PADS can be reconstructed into the PDP using an antenna pattern having a beam width from 0 to 360 degrees as shown in Equation 3.

)는 빔폭필터 생성기(140)에서 생성된 임의의 안테나 빔폭을 가진 안테나 패턴 또는 실제 안테나 패턴을 나타낸다.Here, Ω(

) represents an antenna pattern having an arbitrary antenna beam width generated by the beam width filter generator 140 or an actual antenna pattern.

)를 이용하여 최대 전력을 가지는 부분을 찾은 후에 이를 윈도우로 활용하여 PADS를 수학식 4와 같이 PDP로 재구성할 수도 있다. In addition, the window PDP reconfigurator 130 generates an antenna pattern Ω( with an arbitrary antenna beam width generated by the beam width filter generator 140 from the PADS)

) to find the part with the maximum power, and then use it as a window to reconstruct the PADS into a PDP as shown in Equation 4.

In Equation 4, W is a window meaning an arbitrary beam width for reconstruction, and the window W has a minimum value w ₁ and a maximum value w2. At this time, w ₁ and w ₂ are values obtained as a result of searching for a part with the highest power from the PADS, and are shown in Equation 5.

)의 안테나에서의 채널파라미터를 산출한 결과를 관찰하고자 할때, 수학식 5에서

를 90으로 설정하고, 가장 높은 전력을 가진 빔폭을 탐색한다. 이때 k값을 바꾸어가며 탐색하는데, k의 범위는 -180도에서 +180도까지 1도씩 바꾸어가며 PADS의 합이 최대값(가장 높은 전력에 해당하는 값)이 되는 시점의 k값을 찾는다. 만약 최대값이 되는 시점이 k가 20이었을 때라고 가정한다면, 이때 K는 탐색에 의해 가장 높은 전력을 가지는 w₁과 w₂ 사이의 값을 가지는 90도 빔폭 범위를 의미하며, w₁은 90도 빔폭에서 최소값이므로 -25도(=20-45)이며, w₂는 최대값인 65도(=20+45)가 될 수 있다. In Equation 5, K represents the beam width range having the highest power by search, w ₁ means the minimum value in the K beam width range, and w ₂ means the maximum value in the K beam width range. For example, if the user has a 90 degree beamwidth (

) When trying to observe the result of calculating the channel parameter in the antenna, in Equation 5

is set to 90, and the beam width with the highest power is searched. At this time, the k value is searched by changing, and the range of k is changed by 1 degree from -180 degrees to +180 degrees, and the k value at the time when the sum of PADS becomes the maximum value (value corresponding to the highest power) is found. If it is assumed that the time point at which the maximum value is reached is when k is 20, then K means a 90-degree beam width range having a value between w ₁ and w ₂ having the highest power by search, and w ₁ is a 90-degree beam width Since it is the minimum value in , it is -25 degrees (= 20-45), and w ₂ can be 65 degrees (= 20 + 45), which is the maximum value.

)이나 또는 실제 안테나 패턴 Ω(

)을 이용하여 PDP를 재구성하는 것이다. 두 번째 방법은 빔폭 필터 생성기(140)에서 생성된 임의의 안테나 패턴 Ω(

)을 이용하여 수학식 5와 같이 최대 전력을 찾은 다음, 수학식 4와 같이 PDP를 재구성한다. In this way, according to an embodiment of the present invention, there are two methods of reconfiguring a PDP in the window PDP reconfigurator 130. The first method is an antenna pattern having an arbitrary antenna beam width generated by the beam width filter generator 140 as shown in Equation 3 Ω (

) or the actual antenna pattern Ω(

) to reconstruct the PDP. The second method is an arbitrary antenna pattern generated by the beamwidth filter generator 140 Ω (

) to find the maximum power as in Equation 5, and then reconstruct the PDP as in Equation 4.

FIG. 4 is a diagram showing an example of reconfiguring a PADS into a PDP by setting an arbitrary window in the window PDP reconfigurator shown in FIG. 1 .

When the user uses a rectangular filter with a beam width of 30 degrees, after searching for the part (window) showing the highest power from the PADS, when reconstructing the PDP as shown in Equation 4, it appears as shown in FIG. 4.

)를 산출한다. In addition, the window PAS reconstructor 150 is a power angle spectrum PAS _W (

) is calculated.

Again, referring to FIG. 1, the channel parameter calculator 160 calculates the path loss according to an arbitrary beam width from the reconstructed PDP based on Equation 3 or Equation 4, and the delay of multipath components. Calculate channel parameters such as delay spread. In addition, the channel parameter calculator 160 calculates channel parameters such as angular spread of multipath components according to an arbitrary beam width from the reconstructed PAS as shown in Equation 6. A method of obtaining pathloss and delay spread from PDP and a method of obtaining angular spread from PAS are the same as conventional methods, and thus detailed descriptions thereof are omitted.

In an embodiment of the present invention, when the horn antenna 300 having an arbitrary beam width is rotated in both the horizontal and vertical directions, Equation 2 can be applied as Equation 7, and all information about the 3-dimensional incident angle Considering this, it can be applied and implemented in the same way in the embodiment of the present invention.

5 and 6 are diagrams showing an example of a channel parameter for delay spread and a channel parameter for angular spread, respectively, according to an antenna beam width calculated according to an embodiment of the present invention.

As shown in FIG. 5, the channel characteristic analysis apparatus 100 can calculate statistical channel parameter distribution characteristics for delay spread of multipath components according to various beam widths using a PDP reconstructed based on Equation 4.

In FIG. 5, CDF represents a cumulative density function. That is, when the distribution of delay spread values is accumulated statistically, 0.5 means the average distribution value, and it is possible to observe how much delay spread value corresponds to 0.5.

In addition, as shown in FIG. 6, the channel characteristic analysis apparatus 100 uses the reconstructed PAS as in Equation 6 to determine statistical channel parameter distribution characteristics for the angular spread of multipath components according to various beam widths. yield

7 is a flowchart illustrating a channel characteristic analysis method according to an embodiment of the present invention.

Referring to FIG. 7, the channel characteristic analysis apparatus 100 converts the CIR data measured by rotating the horn antenna 300 having an arbitrary beam width 360 degrees at i degree intervals in the horizontal direction (Azimuth direction) to the radio channel measuring apparatus. It is received from (200) (S710).

The channel characteristic analysis apparatus 100 calculates the PDP for each rotation angle as shown in Equation 1 using the CIR data for each rotation angle (S720).

In addition, the channel characteristic analysis device 100 calculates the PADS as in Equation 2 using the CIR data for each rotation angle (S730).

Next, when receiving the beam width value from the user through the user input unit 400, the channel characteristic analysis apparatus 100 generates a filter corresponding to the antenna pattern having the beam width value received from the user (S750).

The channel characteristic analysis apparatus 100 reconstructs the PDP based on Equation 3 or Equation 4 by using a filter corresponding to the antenna pattern generated in step S750 from the calculated PADS as a window (S760).

The channel characteristic analysis apparatus 100 calculates the PAS within the range of the minimum and maximum values of the window (S770).

The channel characteristic analysis apparatus 100 calculates channel parameters such as path loss according to an arbitrary beam width and delay spread of multipath components from the reconfigured PDP (S780).

Next, the channel characteristic analysis apparatus 100 calculates channel parameters such as angular spread of multipath components according to an arbitrary beam width from the reconstructed PAS (S790).

At least some functions of the device and method for analyzing channel characteristics according to embodiments of the present invention described above may be implemented as hardware or as software combined with hardware. Hereinafter, an embodiment in which a channel characteristic analysis device is coupled to a computer system will be described in detail with reference to FIG. 8 .

8 is a schematic diagram of a channel characteristic analysis apparatus according to another embodiment of the present invention, a system that can be used to perform at least some of the functions of the channel characteristic analysis apparatus 100 described with reference to FIGS. 1 to 7 indicates

Referring to FIG. 8 , the channel characteristic analysis device 800 includes a processor 810, a memory 820, a storage device 830, and an input/output (I/O) interface 840.

The processor 810 may be implemented as a central processing unit (CPU) or other chipset or microprocessor.

The memory 820 may include a medium such as RAM such as dynamic random access memory (DRAM), rambus DRAM (RDRAM), synchronous DRAM (SDRAM), and static RAM (SRAM). can be implemented as

The storage device 830 includes a hard disk, a compact disk read only memory (CD-ROM), a CD rewritable (CD-RW), a digital video disk ROM (DVD-ROM), a DVD-RAM, and a DVD-RW disk. , Blu-ray discs and other optical disks, flash memories, and various types of RAM.

I/O interface 840 allows processor 810 and/or memory 820 to access storage device 830 . Also, the I/O interface 840 may provide an interface with the user input device 400 .

The processor 810 may perform the disparity generation function described in FIGS. 1 to 7, and includes the PDP generator 110, the PADS synthesizer 120, the window PDP reconfigurator 130, the beamwidth filter generator 140, and the window PAS. Program commands for implementing at least some functions of the reconfigurator 150 and the channel parameter calculator 160 may be loaded into the memory 820, and the operations described with reference to FIGS. 1 to 7 may be performed. . Further, these program instructions may be stored in the storage device 830 or may be stored in another system connected through a network.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. that fall within the scope of the right.

Claims (10)

As a method of analyzing channel characteristics in a channel characteristic analysis device,
Calculating a power delay profile from channel data measured by rotating a single antenna at a predetermined angle;
Calculating a power angle delay spectrum from the channel data;
Reconstructing the power delay profile from the power angle delay spectrum using an antenna pattern having a beam width value input from a user through a user input unit;
Calculating a power angle spectrum from the power angle delay spectrum by using a beam width range having the maximum power searched for using the antenna pattern as a window, and
Calculating at least one channel parameter from the reconstructed power delay profile and the power angle spectrum
Channel characteristic analysis method comprising a. In paragraph 1,
The reconstruction step is
Searching for a beam width range having maximum power using the antenna pattern; and
Channel characteristic analysis method comprising the step of reconstructing the power delay profile from the power angle delay spectrum by using the searched beam width range as a window. In paragraph 1,
The reconstructing step includes reconstructing the power delay profile from the power angle delay spectrum using an antenna pattern having a beam width from 0 to 360 degrees. In paragraph 1,
The calculating of the power delay profile comprises collecting the channel data by rotating the antenna in a horizontal direction at a predetermined angle. In paragraph 1,
The calculating of the power delay profile includes collecting the channel data by rotating the antenna horizontally and vertically at a predetermined angle. In paragraph 1,
The single antenna includes a horn antenna. An apparatus for analyzing channel characteristics using a single antenna,
A power delay profile generator for calculating a power delay profile for each angle from channel data measured by rotating the single antenna in horizontal and vertical directions at a predetermined angle;
A power angular delay spectrum synthesizer for calculating a power angular delay spectrum using the channel data;
A beam width filter generator for generating an antenna pattern having a beam width value input from a user;
A window power delay profile reconstructor for reconstructing the power delay profile for each angle using an antenna pattern having a beam width value input from the user, and
A channel parameter calculator for calculating at least one first channel parameter using the reconstructed power delay profile
Channel characteristic analysis device comprising a. In paragraph 7,
A window power angle spectrum reconstructor for calculating a power angle spectrum from the power angle delay spectrum by using the beam width range having the maximum power searched for using the antenna pattern as a window.
Including more,
The channel parameter calculator calculates a second channel parameter using a power angle spectrum within a beam width range having the maximum power. In paragraph 7,
The window power delay profile reconfigurator searches for a beam width range having maximum power using an antenna pattern having a beam width value input from the user, and uses the searched beam width range as a window to determine the power angle delay spectrum from the power angle delay spectrum. A channel characteristic analysis device that reconstructs a power delay profile. In paragraph 7,
Wherein the window power delay profile reconstruction unit reconstructs the power delay profile from the power angle delay spectrum using an antenna pattern having a beam width from 0 to 360 degrees.

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