KR102190255B1 - Fingerprint based beam forming joint transmission system and method - Google Patents

Abstract

The present invention relates to beamforming cooperative communication systems and methods based on a fingerprint, in which the method includes: receiving, by a communication unit, a reference signal reception power, which is strength of a reception signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell, and location information through the serving cell; receiving, by a fingerprint DB construction unit, the reference signal reception power and the location information from the at least one serving cell to select a beam in which strength of the reception signal for each location of the terminal within each serving cell coverage is greatest, and generating fingerprint data with the selected beam to construct a fingerprint database with the generated fingerprint data; sorting, by a terrestrial and aerial fingerprint data sorting unit, terrestrial and aerial fingerprint data according to a location of the terminal in the fingerprint data to generate terrestrial fingerprint data and aerial fingerprint data; and forming, by a serving cell selection unit, at least one serving cell for communicating with the terminal by using at least one of the terrestrial and air fingerprint data to form a communication channel with the terminal through the selected at least one serving cell. Accordingly, efficiency and reliability of terrestrial and aerial data communication are improved.

Description

Fingerprint-based beamforming cooperative communication system and method {FINGERPRINT BASED BEAM FORMING JOINT TRANSMISSION SYSTEM AND METHOD}

The present invention relates to a fingerprint-based beamforming cooperative communication system and method, and more particularly, the efficiency and reliability of data transmission by applying cooperative communication in a communication system applied to a user terminal and an unmanned aerial vehicle using fingerprint data. It relates to one technology that allows you to improve.

Unmanned aerial vehicles (e.g. drones, etc.) have been widely used in civilian applications such as aerial surveillance, traffic control, photography, courier delivery, and communication relay over the past few years. In addition, it is highly useful in various fields such as the aerospace industry and the defense industry, and has the potential to continue to develop.

In various industries using an unmanned aerial vehicle, large capacity, low latency, and high reliability are required through two-way communication between the unmanned aerial vehicle and the base station 100. However, the existing unmanned aerial vehicle relies on one-to-one communication through ISM 2.4GHz, which is an unlicensed band, and cannot meet the requirements of emerging unmanned aerial vehicle applications in terms of data rate, communication range, stability, and security, and the scope of use is significantly limited. There is a risk of becoming.

Millimeter-wave communication is a communication that uses a wide bandwidth of 28 GHz or more, and is a promising technology to achieve high-capacity, low-latency, and high-reliability communication between an unmanned aerial vehicle and a base station. The vehicle system faces new opportunities and challenges.

While millimeter-wave communication can provide an advantageous condition that is not affected by obstacles in the formation of a channel between an unmanned aerial vehicle and a base station, efficient beamforming technology has been developed for data transmission due to the limited communication distance and fast mobility of the unmanned aerial vehicle. I need this.

The beamforming technology selects a beam with the largest signal strength and transmits a signal in a selected direction in order to maximize transmission speed and improve energy efficiency. At this time, the beam selection algorithm requires accurate channel estimation and channel state information feedback for the base station by estimating channel state information (CSI) through exhaustive beam search.

In the thorough beam search, transmission and reception are performed sequentially, and a pair of transmit and receive beams is found that maximizes the signal-to-noise ratio (SNR) of the link while replacing the directional analog beam.

However, this method is determined by the grid resolution, and since all transmitted and received beams must be sequentially transmitted, there is a problem that a large overhead occurs.

Therefore, the millimeter wave beamforming communication to be applied to the unmanned aerial vehicle system is urgently required to develop a technology to overcome the disadvantage of such overhead.

The present invention is to solve the problems of the prior art described above, and improve transmission efficiency and reliability in cooperative communication with an unmanned aerial vehicle through at least one serving cell using fingerprint data in a millimeter wave beamforming communication environment. An object of the present invention is to provide a fingerprint-based beamforming cooperative communication system and method.

The fingerprint-based beamforming cooperative communication system according to an aspect of the present invention may include a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell, wherein the base station, A communication unit for receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell; Receives reference signal reception power and location information from the at least one serving cell, selects a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generates fingerprint data using the selected beam A fingerprint DB construction unit for constructing a fingerprint database from the generated fingerprint data; The fingerprint data may include a ground and aerial fingerprint data selection unit that selects ground and aerial fingerprint data according to a location of the terminal to generate ground fingerprint data and aerial fingerprint data.

Preferably, the base station may further include a serving cell selection unit for selecting at least one serving cell for communication with the terminal using at least one of the terrestrial fingerprint data and the public fingerprint data.

Preferably, the communication unit may establish a communication channel with the terminal through at least one selected serving cell.

A fingerprint-based beamforming cooperative communication system according to another aspect of the present invention may include a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell, and the base station, A communication unit for receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell; Receiving reference signal reception power and location information from the at least one serving cell, selecting a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generating fingerprint data using the selected beam, A fingerprint DB construction unit configured to construct a fingerprint database that generates ground fingerprint data and aerial fingerprint data by selecting ground and aerial fingerprint data according to the location of the terminal; It may include a serving cell selection unit for selecting at least one serving cell for communication with the terminal using the selected terrestrial and public fingerprint data.

Preferably, the communication unit may establish a communication channel with the terminal through at least one selected serving cell.

A fingerprint-based beamforming cooperative communication method according to another aspect of the present invention may include a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell, wherein the base station is A communication step of receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell; Receives reference signal reception power and location information from the at least one serving cell, selects a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generates fingerprint data using the selected beam A fingerprint DB construction step of constructing a fingerprint database using the generated fingerprint data; And selecting ground and aerial fingerprint data from the fingerprint data as ground and aerial fingerprint data according to the location of the terminal to generate ground fingerprint data and aerial fingerprint data.

Preferably, the base station may further include a serving cell selection step of selecting at least one serving cell for communication with the terminal using at least one of the terrestrial fingerprint data and the public fingerprint data.

Preferably, the communication step may establish a communication channel with the terminal through at least one selected serving cell.

A fingerprint-based beamforming cooperative communication method according to another aspect of the present invention may include a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell, wherein the base station is A communication step of receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell; Receiving reference signal reception power and location information from the at least one serving cell, selecting a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generating fingerprint data using the selected beam, A fingerprint DB construction step of constructing a fingerprint database for generating ground fingerprint data and aerial fingerprint data by selecting ground and aerial fingerprint data according to the location of the terminal; A serving cell selection step of selecting at least one serving cell for communication with the terminal by using the selected terrestrial and public fingerprint data.

Preferably, the communication step may establish a communication channel with the terminal through at least one selected serving cell.

According to the present invention, it is possible to improve the efficiency and reliability of data communication between the ground and the air by using a fingerprint in millimeter wave beamforming communication applied to an unmanned aerial vehicle.

1 is a schematic diagram schematically showing a fingerprint-based beamforming cooperative communication environment according to an embodiment.
2 is a block diagram of a system device for cooperative communication in beamforming based on a fingerprint according to an embodiment.
3 is a detailed configuration diagram of a fingerprint DB construction unit according to an embodiment.
4 is a detailed configuration diagram of a ground and aerial fingerprint data selection unit according to an embodiment.
5 is a graph showing SINR CDF efficiency according to the ratio of public terminals.
6 is a graph showing SINR CDF efficiency according to the height of a public terminal.
7 is a flow chart showing a sequence of a fingerprint-based beamforming cooperative communication system according to an embodiment.

In the following, according to the present invention A fingerprint-based beamforming cooperative communication system and method will be described in detail with reference to the accompanying drawings. In this process, thicknesses of lines or sizes of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of the terminal or operator. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

Objects and effects of the present invention may be naturally understood or more clearly understood by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in describing the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a schematic diagram schematically showing a fingerprint-based beamforming cooperative communication environment according to an embodiment.

As shown in FIG. 1, the fingerprint-based beamforming cooperative communication environment according to an embodiment includes a base station 100, at least one serving cell 200 communicating with the base station 100, and a serving cell 200. At least one terminal that communicates may be considered.

A multi-input multi-output (MIMO) network system considers a millimeter-wave massive MIMO system composed of one base station 100, at least one serving cell 200, and at least one terminal.

2 is a block diagram of a system device for cooperative communication in beamforming based on a fingerprint according to an embodiment.

As shown in Fig. 2, the fingerprint-based beamforming cooperative communication system may include a communication unit 110, a fingerprint DB construction unit 130, a terrestrial and public fingerprint data selection unit 150, and a serving cell It may further include a selection unit 170.

In response to a reference signal transmitted to at least one terminal through the at least one serving cell 200, the communication unit 110 provides reference signal reception power and location information, which is the strength of the received signal provided from each terminal, to the serving cell 200. ) Through.

The fingerprint DB construction unit 130 receives reference signal reception power and location information from at least one serving cell 200 and selects a beam having the largest received signal strength for each terminal location within the coverage of each serving cell 200 In addition, fingerprint data may be generated using the selected beam, and a fingerprint database may be constructed from the generated fingerprint data.

The ground and aerial fingerprint data selection unit 150 may select the ground and aerial fingerprint data from the fingerprint data according to the location of the terminal.

The serving cell selection unit 170 may select at least one serving cell 200 for communication with the terminal by using at least one of ground and public fingerprint data.

Here, the communication unit 110 may establish a communication channel with the terminal through the at least one selected serving cell 200. At this time, a signal received by one terminal may interfere with at least one adjacent serving cell 200, but a signal in an adjacent cell causing interference with a beam having the greatest signal strength within the coverage of the serving cell 200 At least one of the beams having the greatest intensity of may be received. That is, the terminal receives at least one signal transmitted through different serving cells 200 through joint transmission from the base station 100, and the beam having the largest received signal strength in each serving cell 200 By forming a communication channel, data can be transmitted and received.

3 is a detailed configuration diagram of a fingerprint DB construction unit according to an embodiment.

As shown in FIG. 3, the detailed configuration of the fingerprint DB construction unit 130 may include a beam index storage module 131 and a terminal location information storage module 133.

The base station 100 may receive reference signal reception power and location information, which is the strength of a received signal, in response to a reference signal transmitted to at least one terminal through at least one serving cell 200.

The beam index storage module 131 may store reference signal reception power, which is the strength of a received signal provided from each terminal, and the terminal location information storage module 133 may receive and store location information. At this time, only the beam with the highest signal strength is stored for the reference signal reception power, and the location information can be easily used with the built-in GPS (Global Positioning System) or a network positioning system. 100).

)는 다음 수학식 1로 표현될 수 있다.The base station 100 is configured with at least one antenna to communicate with at least one serving cell 200, and each serving cell 200 has at least one antenna and an RF chain, and one terminal through one single antenna. Can communicate with At this time, the received signal of terminal k in the serving cell 200 b (

) Can be expressed by the following Equation 1.

[Equation 1]

는 디지털 프리코딩 행렬이고,

는 b 번째 서빙 셀(200)의 데이터 심볼의 벡터이다.

는 열 잡음이고,

는 서빙 셀(200) b에서 기지국(100)

와 단말

사이의 채널 벡터를 나타낸다.In Equation 1,

Is the digital precoding matrix,

Is a vector of data symbols of the b-th serving cell 200.

Is the thermal noise,

The base station 100 in the serving cell 200 b

And terminal

It represents the channel vector between.

The main procedure for selecting a beam having the largest received signal strength at the location of the terminal is beam sweeping through exhaustive search, which can transmit a predefined beam to cover a spatial area of the beam. An interference beam caused by a cell adjacent to the beam having the largest signal strength may be derived by the serving cell 200 through beam sweeping among the predefined spatial directions of the beam.

크기의 공간 이산 푸리에 변환(Discrete Fourier Transform; DFT) 매트릭스

를 사용하여 빔 공간 도메인으로 직접 변환될 수 있다.

개의 안테나 요소를 갖는 ULA(Uniform Linear Array)인 경우, DFT 코드북의 b 번째 빔포밍 벡터는 수학식 2와 같이 표현될 수 있다. The spatial domain channel is

Spatial Discrete Fourier Transform (DFT) matrix of size

Can be directly transformed into the beam space domain using.

In the case of a ULA (Uniform Linear Array) having three antenna elements, the b-th beamforming vector of the DFT codebook may be expressed as Equation 2.

[Equation 2]

In Equation 2, k = 0, 1,..., may have a value of N-1. In the case of UPA, the beamforming vector is calculated by using the Kronecker product of the 1D beamforming vector in each horizontal and vertical domain, and can be expressed as Equation 3.

[Equation 3]

은 크로네커 곱이다.In Equation 3, k is the value of the codeword index in the codebook, k = 0, 1,..., N _v -1, and l = 0, 1,..., N _h -1 Can,

Is the Kronecker product.

는

과 같이 정의된다.Therefore, the beamspace channel

Is

Is defined as

는 단말 k의 빔공간 채널이다. 희소한 빔공간 채널에 따라 적은 수의 적절한 빔만 선택하여 성능 손실 없이 MIMO 시스템의 차원을 줄일 수 있다. 이때, 단말 k의 공간 다중화 이득을 보장하기 위해 필요한 RF 체인의 최소 개수를 N_RF = K 로 설정하면

이다. 여기서, S는 선택된 빔 인덱스 세트이고, 차원 축소된 ZF 행렬 프리코딩

은 다음 수학식 4로 표현될 수 있다.here,

Is a beamspace channel of terminal k. It is possible to reduce the dimension of the MIMO system without loss of performance by selecting only a small number of suitable beams according to sparse beamspace channels. At this time, if the minimum number of RF chains required to guarantee the spatial multiplexing gain of UE k is set to N _RF = K

to be. Here, S is the selected beam index set, and the dimensionally reduced ZF matrix precoding

Can be expressed by Equation 4 below.

[Equation 4]

는 스케일링 계수이다.In Equation 4,

Is the scaling factor.

The channel between the UE and each serving cell 200 is a ray-based channel model in consideration of large-scale fading, small-scale fading, and spatial correlation between each ray. The configuration of the channel may consist of three steps of setting a high-level parameter, a large-scale parameter, and a small parameter, and a UMa (Urban Macro) scenario may be considered to determine the channel parameter. The large-scale fading parameters can be summarized as shown in [Table 1], and the distribution of shadow fading is lognormal.

LoS/NLoS conditions Pathloss [dB] Std [dB] Terminal height LoS

NLoS

에 해당하는 수신 (u) 및 송신 (s) 안테나 사이의 채널 임펄스 응답은 수학식 5와 같이 표현될 수 있다.For small fading, time t and delay

The channel impulse response between the receiving (u) and transmitting (s) antennas corresponding to may be expressed as Equation 5.

[Equation 5]

는 지연 확산이며,

은 Rician 요소,

및

는 각각 NLoS(non-Line of Sight) 및 LoS(Line of Sight) 채널 계수를 나타낸다.In Equation 5,

Is the delayed spread,

Is the Rician element,

And

Represents the non-Line of Sight (NLoS) and Line of Sight (LoS) channel coefficients, respectively.

Here, NLoS is transmitted even if there is an obstacle such as a building, tree, high ground, mountain, or around a high voltage line in the direction of the propagation of the radio wave transmitted from the transmitter to the receiver, and is absorbed or reflected by the obstacle and the radio wave reaches the receiver. It refers to a radio wave in which the phase of the frequency is changed due to the difference in time received or reached with a power lower than that of the time.

LoS means that the propagation of radio waves is not affected by obstacles when reaching from the transmitter to the receiver. This also means that there is little loss of radio waves.

을 경험한다. The probability of the formation of LoS propagation between the serving cell 200 and the UE increases as the height of the UE decreases, so the probability of the LoS increases. In addition, in the shadow fading, in which the signal strength rapidly changes due to buildings or tunnels in the process of transmitting radio waves through various paths, the standard deviation decreases due to a decrease in the path loss index of the channel link as the height of the terminal increases. In particular, in the UMa scenario, if the height of the terminal is 100m or more, the condition of LoS is always followed. At this time, the terminal has a path loss similar to free space propagation

Experience.

The fingerprint data is generated based on the location of the terminal through communication between the base station 100 and the terminal at a location where the ground and public terminals are located within the coverage of each serving cell 200. In this case, as the fingerprint data, beam information having the largest intensity of a received signal within the coverage of the terminal and the serving cell 200 may be considered. Since a terminal located in the air may generate beam interference by at least one adjacent serving cell 200, the strength of the received signal within the coverage of the serving cell 200 is the highest and the strength of the received signal of the interfering cell is the highest. Large beam information can be considered simultaneously.

와

는 각각 공중 및 지상 핑거프린트 위치를 나타낸다.Table 2 shows the location information of the terminal derived by performing a complete search in the serving cell 200 b and fingerprint data in which the beam having the largest received signal strength at the location of the terminal is recorded,

Wow

Represents the aerial and ground fingerprint locations, respectively.

는 간섭 셀 정보,

은 지상 단말(300)의 핑거프린트 위치

에서 신호의 세기가 가장 큰 빔이고,

와

는 각각 공중 단말(400)의 핑거프린트 위치

에서 신호의 세기가 가장 큰 빔과 간섭 셀

에서 신호의 세기가 가장 큰 빔이다.

Is the interfering cell information,

Is the fingerprint location of the ground terminal 300

Is the beam with the largest signal strength at

Wow

Is the fingerprint location of each public terminal 400

Beam and interfering cell with the greatest signal strength in

Is the beam with the largest signal strength in

Public terminal Ground terminal

In the serving cell 200 b, the beam having the largest signal strength for the terminal k is selected from the codebook U through complete search, and may be expressed by Equation 6.

[Equation 6]

The beam having the largest signal strength due to the interfering cell i at the location of the public terminal 400 is determined through complete search, and can be expressed by Equation 7 below.

[Equation 7]

4 is a detailed configuration diagram of a ground and aerial fingerprint data selection unit according to an embodiment.

As shown in FIG. 4, the ground and aerial fingerprint data selection unit 150 may include a ground fingerprint data storage module 151 and a public fingerprint data storage module 153.

The terrestrial fingerprint data storage module 151 stores fingerprint data of a terminal located on the ground.

The public fingerprint data storage module 153 stores fingerprint data of a terminal located in the air.

Here, the process of classifying the fingerprint data of the ground terminal 300 and the public terminal 400 into the ground fingerprint data and the public fingerprint data is performed by the base station 100 using the location information provided from the terminal. The fingerprint data is generated, and the current location of the terminal and the location of the generated fingerprint data are matched. Matching the current location of the terminal and the location of the fingerprint data means identifying the location of the fingerprint data with the smallest error range from the current location of the terminal in the fingerprint database, and the matched location of the terminal k is calculated as follows: It can be expressed by Equation 8.

[Equation 8]

는 단말 k의 현재 위치이고,

는 핑거프린트 위치 i이며, 결과적으로, 단말의 현재 위치와 가장 가깝게 매칭된 핑거프린트 위치를 얻을 수 있다.In Equation 8,

Is the current location of terminal k,

Is the fingerprint location i, and as a result, it is possible to obtain a fingerprint location that closely matches the current location of the terminal.

After matching, the base station 100 may determine the ground terminal 300 or the public terminal 400 through the matched fingerprint location.

When the location of the fingerprint matching the location of the terminal is on the ground, the terminal can be identified as the ground terminal 300, and when the location of the matching fingerprint is in the air, the terminal can be identified as the public terminal 400. have.

After identifying the location of the terminal, the base station 100 may establish a communication channel by selecting the serving cell 200 for communicating with the terminal.

Here, when the terminal is located on the ground, the base station 100 may communicate with the ground terminal 300 using a beam having the greatest intensity of a received signal according to fingerprint data corresponding to the matched fingerprint location.

When the terminal is located in the air, the public terminal 400 experiences at least one serving cell adjacent to the public terminal 400 as it experiences LoS propagation conditions for more adjacent serving cells 200 than the ground terminal 300. Joint Transmission (JT), which simultaneously forms a communication channel from 200, may be applied.

At this time, if the base station 100 knows the exact channel state information of the terminal, the SINR (Signal Interference Noise Ratio) of cooperative communication applied to the public terminal 400 through at least one serving cell 200 is Equation 9 It can be expressed as

[Equation 9]

는 서빙 셀 j로부터 전송된 신호에 대한 단말의 수신 전력이고,

는 서빙 셀 c로부터 전송된 신호에 대한 단말의 수신 전력이다. B는 기지국(100), C는 협력 통신하는 서빙 셀(200)을 나타낸다.In Equation 9,

Is the received power of the terminal for the signal transmitted from the serving cell j,

Is the received power of the terminal for the signal transmitted from the serving cell c. B represents the base station 100, C represents a serving cell 200 for cooperative communication.

The SINR of the terrestrial terminal 300 to which cooperative communication is not applied may be expressed by Equation 10 below.

는 서빙 셀 j로부터 전송된 신호에 대한 단말의 수신 전력이고,

는 서빙 셀 b로부터 전송된 신호에 대한 단말의 수신 전력이다.In Equation 10,

Is the received power of the terminal for the signal transmitted from the serving cell j,

Is the received power of the terminal for the signal transmitted from the serving cell b.

simulation

The parameters used in the simulation are based on a bandwidth of 100 MHz with a carrier frequency of 30 GHz in the downlink system. For the UMa scenario, 19 serving cells 200 are composed of 3 sectors, so that a total of 57 serving cells 200 layouts are arranged, and the total number of terminals per serving cell 200 is the terrestrial terminal 300 and the aerial It is assumed that there are a total of 15 including the terminal 400. While the public terminal 400 is configured as an outdoor terminal having a much higher height than the ground, it is assumed that the ground terminal 300 exists on the ground and in an internal building.

In order to evaluate the influence of the public terminals 400 of different densities in the serving cell 200, the ratio of the public terminals 400 to the total number of terminals is applied as 0%, 0.67%, 7.1%, 25%, and 50%. Thus, the cumulative distribution function (CDF) of SINR was considered. Detailed simulation parameters are shown in Table 3.

parameter home Cell layout Hexagonal grid, 19 cell site, 3 sector/site Center frequency 30 GHz Bandwidth 100 MHz scenario UMa Number of terminals per sector 15 terminals Aerial terminal ratio (N _aerial /N _terretrial ) Case 1: 0% (N _aerial = 0)
Case 2: 0.67% (N _aerial = 0.1)
Case 3: 7.1% (N _aerial = 1)
Case 4: 25% (N _aerial = 3)
Case 5: 50% (N _aerial = 5) Antenna configuration Base station 100: N _h = N _v = 8, N _BS = 64 Terminal: single antenna Base station maximum TX power 35 dBm Scheduling Round Robin Traffic model Full buffer Vertical antenna pattern (dB)

Horizontal antenna pattern (dB)

3D antenna combination method

5 is a graph showing SINR CDF efficiency according to the ratio of public terminals.

As shown in FIG. 5, the SINR CDF efficiency according to the ratio of public terminals is the number of public terminals 400 out of the total number of terminals (15), that is, Cases 1, 2, 3, 4, and 5 are 0 and 0.1, respectively. , 1, 3, and 5 are considered. At this time, the signal received by the public terminal 400 shows an average -3.5 dB performance change compared to the downlink SINR of the terrestrial terminal 300 due to interference of at least one adjacent serving cell 200, but the data is transmitted due to cooperative communication. Because it receives, more data can be transmitted.

6 is a graph showing SINR CDF efficiency according to the height of a public terminal.

As shown in FIG. 6, the SINR CDF efficiency according to the height of the public terminal 400 is based on the case where the ratio of the public terminal 400 is 50%. At this time, the height of the public terminal 400 considers SINR CDF efficiency according to 50, 100, 200, and 300m. SINR CDF efficiency according to the height of the public terminal 400 decreases as the height of the public terminal 400 increases from 50 m to the maximum flight altitude of 300 m, the performance of the downlink channel decreases, but the height of the public terminal 400 increases. Accordingly, the probability that the public terminal 400 receives LoS signals from several serving cells 200 increases, and path loss between the public terminal 400 and the serving cell 200 is reduced.

7 is a flowchart illustrating a sequence of a fingerprint-based beamforming cooperative communication according to an embodiment.

As shown in FIG. 7, the order of the fingerprint-based beamforming cooperative communication is a communication step (S100), a fingerprint DB construction step (S300), a terrestrial and public fingerprint data selection step (S500), and a serving cell selection step (S700). ), may include a cooperative communication step (S900).

In the communication step (S100), in response to a reference signal transmitted from the base station to at least one terminal through at least one serving cell 200, the reference signal reception power and location information, which is the strength of the received signal provided from each terminal, are served. It can be received through the cell 200.

The fingerprint DB construction step (S300) receives reference signal reception power and location information from at least one serving cell 200 and generates a beam having the largest received signal strength for each location of a terminal within the coverage of each serving cell 200. By selecting and generating fingerprint data with the selected beam, a fingerprint database may be constructed from the generated fingerprint data.

In the step S500 of selecting ground and aerial fingerprint data, the fingerprint data may be selected as ground and aerial fingerprint data according to the location of the terminal.

In the serving cell selection step (S700), the base station 100 may select at least one serving cell 200 for communication to the terminal using at least one of ground and public fingerprint data.

The cooperative communication step (S900) may establish a communication channel with the terminal through the selected at least one serving cell 200.

Although the present invention has been described in detail through exemplary embodiments above, those of ordinary skill in the art to which the present invention pertains will understand that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. will be. Therefore, the scope of the present invention is limited to the described embodiments and should not be determined, and should be determined by all changes or modifications derived from the claims and the concept of equality as well as the claims to be described later.

100: base station 200: serving cell
300: ground terminal 400: air terminal
110: communication unit 130: fingerprint DB construction unit
150: ground and aerial fingerprint data selection unit
170: serving cell selection unit
131: beam index storage module 133: terminal location information storage module
151: terrestrial fingerprint data storage module
153: public fingerprint data storage module

Claims (10)

In the fingerprint-based beamforming cooperative communication system comprising a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell,
The base station,
A communication unit for receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell;
Receives reference signal reception power and location information from the at least one serving cell, selects a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generates fingerprint data using the selected beam A fingerprint DB construction unit for constructing a fingerprint database from the generated fingerprint data;
A fingerprint-based beamforming cooperative communication system including a ground and aerial fingerprint data selection unit that generates ground and aerial fingerprint data by selecting ground and aerial fingerprint data from the fingerprint data according to the location of the terminal. .
The method of claim 1,
The base station,
A fingerprint-based beamforming cooperative communication system further comprising a serving cell selection unit for selecting at least one serving cell for communication with a terminal using at least one of the terrestrial fingerprint data and the public fingerprint data.
The method of claim 2,
The communication unit is a fingerprint-based beamforming cooperative communication system, characterized in that forming a communication channel with the terminal through at least one selected serving cell.
In the fingerprint-based beamforming cooperative communication system comprising a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell,
The base station,
A communication unit for receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell;
Receiving reference signal reception power and location information from the at least one serving cell, selecting a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generating fingerprint data using the selected beam, A fingerprint DB construction unit configured to construct a fingerprint database that generates ground fingerprint data and aerial fingerprint data by selecting ground and aerial fingerprint data according to the location of the terminal;
A fingerprint-based beamforming cooperative communication system comprising a serving cell selection unit for selecting at least one serving cell for communication with a terminal using the selected terrestrial and aerial fingerprint data.
The method of claim 4,
The communication unit is a fingerprint-based beamforming cooperative communication system, characterized in that forming a communication channel with the terminal through at least one selected serving cell.
In the fingerprint-based beamforming cooperative communication method comprising a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell,
The base station,
A communication step of receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell;
Receives reference signal reception power and location information from the at least one serving cell, selects a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generates fingerprint data using the selected beam A fingerprint DB construction step of constructing a fingerprint database using the generated fingerprint data;
Fingerprint-based beamforming cooperative communication comprising the step of selecting ground and aerial fingerprint data to generate ground fingerprint data and aerial fingerprint data by selecting ground and aerial fingerprint data from the fingerprint data according to the location of the terminal Way.
The method of claim 6,
The base station,
The fingerprint-based beamforming cooperative communication method further comprising a serving cell selection step of selecting at least one serving cell for communication with the terminal using at least one of the terrestrial fingerprint data and the public fingerprint data.
The method of claim 7,
The communication step is a fingerprint-based beamforming cooperative communication method, characterized in that forming a communication channel with the terminal through at least one selected serving cell.
In the fingerprint-based beamforming cooperative communication method comprising a base station, at least one serving cell in communication with the base station, and at least one terminal in communication with the serving cell,
The base station,
A communication step of receiving, through the serving cell, reference signal reception power and location information, which is the strength of a received signal provided from each terminal in response to a reference signal transmitted to at least one terminal through at least one serving cell;
Receiving reference signal reception power and location information from the at least one serving cell, selecting a beam having the largest received signal strength for each location of a terminal within each serving cell coverage, and generating fingerprint data using the selected beam, A fingerprint DB construction step of constructing a fingerprint database for generating ground fingerprint data and aerial fingerprint data by selecting ground and aerial fingerprint data according to the location of the terminal;
A fingerprint-based beamforming cooperative communication method comprising the step of selecting a serving cell for selecting at least one serving cell for communication with the terminal using the selected terrestrial and aerial fingerprint data.
The method of claim 9,
The communication step is a fingerprint-based beamforming cooperative communication method, characterized in that forming a communication channel with the terminal through at least one selected serving cell.

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