WO2018026159A1

WO2018026159A1 - Method for predicting signal quality in wireless network and device for performing method

Info

Publication number: WO2018026159A1
Application number: PCT/KR2017/008271
Authority: WO
Inventors: 윤병완
Original assignee: 주식회사 케이티
Priority date: 2016-08-03
Filing date: 2017-08-01
Publication date: 2018-02-08
Also published as: KR20180015383A; KR101856752B1

Abstract

The present invention relates to a method for predicting a signal quality in a wireless network and a device for performing the method, and disclosed is a method for signal quality prediction in a wireless network, comprising the steps of: allowing a signal quality prediction device to receive information on a terminal, a serving base station, and one or more adjacent base stations positioned in a predetermined distance range from the serving base station in the wireless network; calculating a first signal transmitted/received between a specific terminal moving within a serving base station cell and the serving base station; calculating a second signal transmitted/received between the specific terminal and the one or more adjacent base stations; calculating a third signal on the basis of a moving speed of the specific terminal, subcarrier spacing of the first signal, and a frequency of the first signal; and calculating a signal quality for the specific terminal on the basis of the first signal, the second signal, the third signal, and a thermal noise value within the wireless network.

Description

Signal quality prediction method in wireless network and apparatus for performing the method

The present invention relates to a method for predicting signal quality in a wireless network and an apparatus for performing the method, and more particularly, to reflects a Doppler effect generated as a terminal moves in a wireless network including a plurality of base stations. The present invention relates to a method of predicting signal quality more accurately, and an apparatus for performing the method.

As communication technology develops, the necessity of accurately predicting and analyzing signal quality at a user terminal side is increasing in order to provide a high quality communication service to a user.

Conventionally, in the signal quality prediction in a wireless network, the emphasis was placed on considering interference by neighboring base stations around a serving cell.However, for accurate signal quality prediction, in addition to the interference between the cells, It is also necessary to consider changes in signal characteristics due to the Doppler effect. In particular, when the high-speed mobile unit becomes a terminal as in the LTE-R system, such a need is further increased.

The Doppler effect is an effect that occurs when one or more of the wave source causing the wave and the observer observing the wave is moving, and the frequency of the wave is higher when the distance between the wave source and the observer is narrowed. For example, when the distance increases, the frequency of the wave is observed lower.

The present invention was devised to solve the above problems of the prior art, and in estimating signal quality in a wireless network, it is possible to reflect the Doppler effect due to the movement of the terminal as well as interference by neighboring base stations in addition to the serving base station. It is an object of the present invention to provide a method and an apparatus for performing the method.

Signal quality prediction method in a wireless network according to an embodiment of the present invention for solving the above problems,

Receiving, by a signal quality prediction apparatus, information about a terminal in a wireless network, a serving base station, and one or more neighboring base stations located within a predetermined distance range from the serving base station; Calculating a first signal transmitted and received between a specific terminal moving in a cell of the serving base station and the serving base station; Calculating a second signal transmitted and received between the specific terminal and the one or more neighboring base stations; Calculating a third signal based on a moving speed of the specific terminal, a subcarrier spacing of the first signal, and a frequency of the first signal; And calculating a signal quality for the specific terminal based on the first signal value, the second signal value, the third signal value, and a thermal noise value in the wireless network.

The receiving of the information may include determining the predetermined distance range in consideration of output signals of the serving base station and one or more neighboring base stations.

The calculating of the first signal may be performed based on an output signal allocated to the specific terminal among the output signals of the serving base station and a distance between the serving base station and the specific terminal, and calculating the second signal. The step may be calculated based on an output signal allocated to the specific terminal among the output signals of each of the one or more neighboring base stations and the distance between each of the one or more neighboring base stations and the specific terminal.

Preferably, calculating the third signal may be calculated according to Equation 3 below, and calculating the signal quality for the specific terminal may be calculated according to Equation 4 below.

[Equation 3]

[Equation 4]

Here, NT is 1 / (subcarrier spacing of the first signal), N is the number of subcarriers of the first signal, f is the original frequency of the first signal, f _d is the first according to the movement of the specific terminal The transition frequency of the signal, V is the speed of the first signal, V _moving is the _moving speed of the specific terminal, q is a natural number less than or equal to N.

Signal quality prediction apparatus in a wireless network according to an embodiment of the present invention for solving the above problems,

A communication unit for receiving information about a terminal in a wireless network, a serving base station, and at least one neighboring base station located in a range of a predetermined distance from the serving base station; A first signal transmitted and received between a specific terminal moving in the serving base station cell and the serving base station, a second signal transmitted and received between the specific terminal and the at least one neighboring base station, and a moving speed of the specific terminal and the first signal Calculating a third signal based on a subcarrier spacing and a frequency of the first signal, and calculating a signal quality for the specific terminal based on the first signal, the second signal, the third signal, and a thermal noise value in the wireless network A calculator; A memory unit may store a terminal, a serving base station and at least one neighboring base station received by the communication unit, and information about an output signal of each base station.

In the present invention, in estimating signal quality in a wireless network, the signal quality can be predicted more accurately by reflecting the Doppler effect generated as the terminal moves.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide examples of the present invention and together with the description, describe the technical idea of the present invention.

1 illustrates a system for analyzing signal quality in a wireless network according to the present invention.

2 is a flowchart illustrating a method for analyzing signal quality in a wireless network according to the present invention.

3 schematically illustrates a wireless network environment according to the present invention.

4 illustrates a configuration of an apparatus for predicting signal quality in a wireless network according to the present invention.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be described in detail with reference to the accompanying drawings.

The following examples are provided to assist in a comprehensive understanding of the methods, devices, and / or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification. The terminology used in the description is for the purpose of describing particular embodiments only and should not be limiting. Unless expressly used otherwise, the singular forms “a,” “an,” and “the” include plural forms of meaning. In this description, expressions such as "comprises" or "equipment" are intended to indicate certain features, numbers, steps, actions, elements, portions or combinations thereof, and one or more than those described. It should not be construed to exclude the presence or possibility of other features, numbers, steps, actions, elements, portions or combinations thereof.

In addition, terms such as first and second may be used to describe various components, but the components are not limited by the terms, and the terms are used to distinguish one component from another component. Used only as

Hereinafter, a signal quality prediction method in a wireless network and an apparatus for performing the method according to the present invention will be described in detail with reference to the accompanying embodiments.

As can be seen in Figure 1, the system for analyzing the signal quality in a wireless network according to the present invention, the signal quality prediction apparatus 100, the base station 200, the terminal 300 and communication connecting each component It may be configured to include a network (10). Additionally, the database 400 may further include.

The signal quality prediction apparatus 100 may receive identification information, location information, and information on an output signal of each from the base station 200 and the terminal 300 in the wireless network. The information may be received not only directly from the base station 200 and the terminal 300, but also from a database 400 provided separately. Conversely, the information received from the base station 200 and the terminal 300 may be transmitted to the database 400 again for storage and management. In addition, the identification information, location information and information on the output signal, etc. may be directly input through a separate input device from the manager of the wireless network.

The signal quality prediction apparatus 100 may calculate the signal quality at the base station 200 or the terminal 300 by using the received information. The process of calculating the signal quality will be described later in more detail.

The signal quality prediction apparatus 100 may include an electronic device that may perform functions such as data operation processing, data transmission and reception, and is not limited in function, and may change or expand a substantial portion of functions through an application program. Can be. In addition, although it may be implemented as one physical server, it is also possible to implement as a plurality of physical servers, if necessary.

The base station 200 refers to a point for communicating with the terminal 300, and may transmit its identification information, location information, and information about an output signal to the signal quality prediction apparatus 100. The base station 200 may be referred to in other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and the like. The base station 200 may be configured with one or more to form the wireless network, and may be divided into a serving base station and an adjacent base station based on the relationship with the terminal 300.

The terminal 300 may perform functions such as data operation processing, data transmission and reception, and may include an electronic device that is not limited in function and can be driven through an application program. The terminal 300 may include a mobile communication terminal such as a tablet PC, a laptop, a smart phone, and the like.

The database 400 may include information on identification information, location information and output signal of the base station 200, and location information of the terminal 300. The information may be received directly from the base station 200 and the terminal 300, or may be provided by an administrator's input. In addition, although the database 400 is illustrated as a separate configuration from the signal quality prediction apparatus 100, the database 400 may be a configuration included in the signal quality prediction apparatus 100.

The communication network 10 may mediate data transmission and reception between the server 100 and the terminal device 200. Specifically, the communication network 10 may include a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), and the like. The communication network 10 may also include a known World Wide Web (WWW). However, the communication network 10 according to the present invention is not limited to the networks listed above.

2 and 3, a method of estimating signal quality in a wireless network and a method of calculating a signal transmitted / received between the base station 200 and the terminal 300 will be described.

Referring to Figure 2, the signal quality prediction method in a wireless network according to the present invention, the step of receiving information about the terminal and the base station (S110), calculating the first signal (S120), calculating the second signal The step S130, the third signal calculating step S140, and the signal quality calculating step S150 may be included.

First, in step S110, the signal quality prediction apparatus 100 according to the present invention collects information about the base station 200 and the terminal 300 in the wireless network. The information may include identification information, location information, information on an output signal, and the like of each base station 200. In addition, the information may be directly received from the base station 200 and the terminal 300, and separate to receive and manage the location information of all the base station 200 and the terminal 300 in the wireless network, and periodically updated It may be received from the database 400 of. In addition, the information may be directly input through a separate input device from the administrator of the wireless network.

The base station 200 may be divided into a serving base station and an adjacent base station. A region in which a range of transmission signals of each base station is roughly divided is called a cell, and a base station that transmits an output signal to a cell to which the terminal 300 belongs and provides an appropriate communication service is specifically called a serving base station.

Meanwhile, the neighboring base station may generally include all other base stations other than the serving base station, but for convenience of calculation, the neighboring base station is located within a predetermined distance range from the serving base station, and may interfere with data communication between the terminal 300 and the serving base station. It can be limited to a base station that transmits a working signal. In addition, the adjacent base station may be a base station located in a predetermined distance range from the terminal 300.

The predetermined distance range may be determined based on the output signal strength at the base station 200. For example, the weaker the output signal strength of the serving base station and / or the stronger the output signal strength of the neighboring base station, the greater the interference effect on the terminal 300 should be considered in a wider area, so that the terminal 300 The predetermined range of distance can be relatively wide to more accurately predict the signal quality for. On the contrary, as the output signal strength of the serving base station is stronger and / or the output signal strength of the neighboring base station is weaker, the influence of interference on the terminal 300 may be considered in a narrower area. Can be relatively narrow.

In step S120 calculates a first signal transmitted and received between a specific terminal in the serving base station cell and the serving base station. The first signal is calculated based on the location of the serving base station, the output signal allocated to the specific terminal 310 among the output signals of the serving base station 210, the location of the specific terminal, and the like.

For example, in FIG. 3, since a specific terminal 310 currently exists in a cell of the base station 210 having l = 0, the base station 210 having l = 0 may serve a serving base station 210 for the specific terminal 310. )to be. The first signal may be calculated based on the distance between the serving base station 210 and the specific terminal 310 and the output signal of the serving base station 210, and more specifically, may be calculated according to Equation 1 below.

[Equation 1]

Here, k is a specific terminal in a cell of the serving base station, M _UE is the number of Resource Blocks (hereinafter, RB) allocated to a specific terminal, M is the total number of RB, P _Tx is the output signal of the serving base station, pathloss is serving It means a loss according to the distance between the base station 210 and the specific terminal 310.

In operation S130, a second signal transmitted and received between the specific terminal 310 and the neighboring base stations 221 to 226 is calculated. The second signal is a position of each of the neighboring base stations 221 to 226 except for the serving base station 210 among the base stations, an output signal allocated to the specific terminal 310 among the output signals of each of the neighboring base stations, and the specific terminal ( It calculates based on the position of 310, etc.

For example, in FIG. 3, the base stations j = 1 to 6 except for the serving base station 210 for the specific terminal 310 are adjacent base stations 221 to 226. The second signal is calculated based on the location of each of the neighboring base stations 221 to 226 and the specific terminal 310, and the output signal of the serving base station 210. More specifically, the second signal is calculated according to Equation 2 below. can do.

[Equation 2]

Here, k is a specific terminal in a cell of the serving base station, M _UE is the number of RBs allocated to a specific terminal, M is the total number of RBs, P _Ty is the output signal of the neighboring base station, pathloss is each neighboring base station (221 to 226 means a loss based on a distance between the specific terminal 310. For convenience of explanation, it is assumed that the output signals of the neighboring base stations 221 to 226 are the same, but the output signal of the base station may vary according to each base station.

In addition, in FIG. 3, for convenience of description, the predetermined distance range is limited to include only the base stations 221 to 226 surrounding the serving base station 210. However, as described above in step S110, the serving base station 210 may be located in the serving base station 210. The range of the adjacent base station for the can vary depending on the predetermined distance range is set.

In operation S140, a third signal is calculated based on the moving speed of the specific terminal 310 and the output signal characteristics of the serving base station 210.

The third signal is a value for reflecting the characteristic change of the first signal due to the Doppler effect generated by the movement of the terminal 300 generated in the wireless network and acts as a kind of interference as the second signal.

An effect that occurs when one or more of the wave-generating wave source and the observer observing the wave is in motion; the frequency of the wave is higher when the distance between the wave source and the observer is narrower, and when the distance is farther, The lower observed phenomenon is called the Doppler effect. This phenomenon naturally occurs in wireless communication, but in general, the base station 200 is fixedly installed, but in the case of the user terminal 300, since the user moves along with the movement of the user, the Doppler effect is required for accurate signal quality prediction. Consideration should be given to changes in signal characteristics.

Although the output signal from the base station 200 may be various, in the present invention, it is assumed that the wireless network is an output signal of an Orthogonally Frequency Division Multiplexing (OFDM) scheme. Subcarrier spacing and the frequency value of the first signal.

The third signal may be calculated based on the moving speed of the specific terminal 310, the subcarrier spacing of the first signal, and the frequency of the first signal, and more specifically, may be calculated according to Equation 3 below. .

[Equation 3]

In step S150 calculates a signal quality for the specific terminal 310 in the wireless network according to the present invention. The signal quality for the specific terminal 300 may be calculated based on the first signal value, the second signal value, and the third signal value calculated in the previous step and the thermal noise power in the wireless network. More specifically, it may be calculated according to Equation 4 below.

[Equation 4]

The calculated signal quality is not only the first signal from the serving base station 210 and the second signal from the neighboring base stations 221 to 226 which are received in a fixed state without the specific terminal 310 moving. By accurately reflecting interference due to the Doppler effect as the terminal 310 moves, it is possible to predict a more accurate signal quality.

For convenience of description, the signal quality prediction in the wireless network according to the present invention has been described on the premise of predicting the signal quality for a single specific terminal 300. However, it is assumed that the terminal exists in the entire area of the wireless network. By doing so, it is possible to construct a signal quality map of the entire area.

4 is a block diagram of a signal quality prediction apparatus 100 in a wireless network according to the present invention.

Referring to FIG. 4, the signal quality predicting apparatus 100 according to the present invention may include a communication unit 110, an operation unit 120, and a memory unit 130.

The communication unit 110 may receive information such as identification information, location, and output signal strength of each from the base station 200 and the terminal 300 in the wireless network. The information may be received not only directly from the base station 200 and the terminal 300, but also from a database 400 provided separately. In addition, the information received from the base station 200 and the terminal 300 may be transmitted to the database 400 again and stored.

The calculation unit 120 is a first signal transmitted and received between the specific terminal 310 and the serving base station 210 moving in the cell of the serving base station 210 by using the information received from the communication unit 110, the specified A third signal based on a second signal transmitted and received between the terminal 310 and the one or more neighboring base stations 221 to 226, the moving speed of the specific terminal 310, the subcarrier spacing of the first signal, and the frequency of the first signal. The signal may be calculated and the signal quality of the specific terminal 310 may be calculated based on the first signal, the second signal, and the third signal.

The memory unit 130 is the location of the terminal 300, the serving base station 210 and one or more neighboring base stations 221 to 226 received from the communication unit 110, and the serving base station 210 and one or more neighboring base stations. Information relating to the output signal of the (221 to 226) can be stored.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, a DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, but are not limited to these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas falling within the scope of the present invention should be construed as being included in the scope of the present invention.

Claims

Receiving, by a signal quality prediction apparatus, information about a terminal in a wireless network, a serving base station, and one or more neighboring base stations located within a predetermined distance range from the serving base station;

Calculating a first signal transmitted and received between a specific terminal moving in a cell of the serving base station and the serving base station;

Calculating a second signal transmitted and received between the specific terminal and the one or more neighboring base stations;

Calculating a third signal based on a moving speed of the specific terminal, a subcarrier spacing of the first signal, and a frequency of the first signal; And

Calculating a signal quality for the specific terminal based on the first signal value, the second signal value, the third signal value, and a thermal noise value in the wireless network. Signal quality prediction method.
The method of claim 1,

Receiving the information,

And determining the predetermined distance range in consideration of output signals of the serving base station and at least one neighboring base station.
The method of claim 1,

Computing the first signal,

Calculated based on an output signal allocated to the specific terminal among the output signals of the serving base station and a distance between the serving base station and the specific terminal,

Computing the second signal,

And calculating the signal quality based on an output signal allocated to the specific terminal among the output signals of each of the one or more neighboring base stations and the distance between each of the one or more neighboring base stations and the specific terminal.
The method of claim 1,

Computing the third signal,

Calculated according to Equation 3 below,

Computing the signal quality for the specific terminal,

Signal quality prediction method for a wireless network, characterized in that it is calculated according to the following equation (4).

[Equation 3]

[Equation 4]

Here, NT is 1 / (subcarrier spacing of the first signal), N is the number of subcarriers of the first signal, f is the original frequency of the first signal, f d is the first according to the movement of the specific terminal The transition frequency of the signal, V is the speed of the first signal, V moving is the moving speed of the specific terminal, q is a natural number less than or equal to N.
A communication unit for receiving information about a terminal in a wireless network, a serving base station, and at least one neighboring base station located in a range of a predetermined distance from the serving base station;

A first signal transmitted and received between a specific terminal moving in the serving base station cell and the serving base station, a second signal transmitted and received between the specific terminal and the at least one neighboring base station, and a moving speed of the specific terminal and the first signal Calculating a third signal based on a subcarrier spacing and a frequency of the first signal, and calculating a signal quality for the specific terminal based on the first signal, the second signal, the third signal, and a thermal noise value in the wireless network A calculator;

And a memory unit for storing the information about the terminal, the serving base station and one or more neighboring base stations received by the communication unit, and the output signal of each base station.
A computer program stored in a medium in combination with hardware to execute a method for predicting signal quality in a wireless network according to any one of claims 1 to 4.