KR101925568B1 - Apparatus and method for deciding boundary movement direction in cellular network - Google Patents

Abstract

A boundary movement direction determination apparatus in a cellular network according to an embodiment of the present invention includes a basic information acquisition unit for acquiring information on a data transmission rate between a terminal and a base station and information on a signal-to- For each of the case of applying the entire frequency reuse to the base station at the transmission rate and the case of applying the partial frequency reuse to the base station, the outage probability of the communication between the terminal and the base station varying according to the signal- A first frequency reuse scheme having a lower signal-to-noise ratio in achieving a predetermined target disruption probability during the entire frequency reuse and partial frequency reuse is a second frequency reuse scheme different from the first frequency reuse scheme, Method, the moving direction of the boundary is determined based on the change And a control unit.

Description

[0001] APPARATUS AND METHOD FOR DECIDING BOUNDARY MOVEMENT DIRECTION IN CELLULAR NETWORK [0002]

The present invention relates to an apparatus and method for determining a boundary movement direction in a cellular network, and more particularly, to an apparatus and method for determining a boundary movement direction in a cellular network, in which a terminal in a cell efficiently uses the entire frequency reuse and partial frequency reuse The present invention relates to a boundary moving direction determination apparatus and method in a cellular network that determines a direction in which a boundary that divides frequency reuse regions is moved.

Since the wireless communication system after 3G requires a higher data rate than the conventional one, a multipath delay causing inter-symbol interference (ISI) is a problem. Orthogonal Frequency Division Multiplexing (OFDM) has attracted attention as a technique for attenuating the above-mentioned ISI.

Briefly, with respect to OFDM, OFDM converts serial data symbols into N parallel data symbols, carries them on separate N subcarriers, and the subcarriers have orthogonality in the frequency dimension. Each orthogonal channel experiences mutually independent frequency selective fading, and the spacing of transmitted symbols becomes longer. Accordingly, the ISI can be minimized.

In the meantime, a cell in a wireless communication system means that an area where a communication service is provided is divided into small areas in order to efficiently use the frequency. Generally, a base station is installed in the center of such a cell.

In an OFDM system in a multi-cell environment, neighboring cells can use the same subcarrier. However, this can cause interference to users. This interference is referred to as inter-cell interference.

The above-described inter-cell interference can be reduced by increasing partial frequency reuse. At this time, as the transmission power of the base station changes, the boundaries for distinguishing each frequency reuse region are changed so as to efficiently use the entire frequency reuse and partial frequency reuse. In order to investigate this, it is necessary to directly find the boundary where the probability of stopping is lowered by applying the entire frequency reuse or partial frequency reuse in all areas of the cell of the base station.

A problem to be solved in the embodiment of the present invention is to provide a technique for determining a direction in which a boundary for dividing each frequency reuse region is moved so that the entire frequency reuse and partial frequency reuse can be efficiently used as the transmission power of the base station is changed .

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

A boundary in a cellular network according to an embodiment of the present invention for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station The moving direction determination apparatus includes a basic information obtaining unit that obtains information on a data transmission rate between a mobile station and the base station and information on a signal-to-noise ratio in the mobile station; And for applying the partial frequency reuse, the probability of acquiring the information on the outage probability that the communication between the terminal and the base station, which varies according to the signal-to-noise ratio at the terminal, An information acquiring section for acquiring a target stop probability; When the first frequency reuse scheme having a lower signal-to-noise ratio during use and the partial frequency reuse is changed to a second frequency reuse scheme different from the first frequency reuse scheme, the direction of movement of the boundary is determined based on the change And a control unit.

In this case, if the first frequency reuse method is full frequency reuse and the second frequency reuse method is partial frequency reuse, the controller can determine that the boundary moves toward the center of the cell.

Also, the controller may determine that the boundary moves toward the edge of the cell when the first frequency reuse method is partial frequency reuse and the second frequency reuse method is all frequency reuse.

A boundary in a cellular network according to an embodiment of the present invention for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station The moving direction determination apparatus includes a basic information obtaining unit that obtains information on a data transmission rate between a terminal and the base station and information on a signal-to-noise ratio in the terminal, A first outage probability that communication between the subscriber station and the base station changes depending on a signal-to-noise ratio at the subscriber station, and a second outage probability that changes according to a signal-to-noise ratio at the subscriber station when the partial frequency reuse is applied to the base station. A probability information acquisition unit for acquiring a second probability of interruption in communication between the mobile station and the base station; This portion and the first stop probability and the probability of intersection between the reference stop and the second stop probability and a controller to determine the direction of movement of the boundary on the basis of the direction of travel, as the data transfer rate changes.

At this time, the control unit can determine that the boundary moves toward the center of the cell when the reference interruption probability increases as the data transmission rate changes.

Also, the control unit can determine that the boundary moves toward the edge of the cell when the reference interruption probability decreases as the data transmission rate changes.

A boundary in a cellular network according to an embodiment of the present invention for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station A method for determining a movement direction comprises the steps of: acquiring information on a data transmission rate between a terminal and a base station and information on a signal-to-noise ratio in the terminal; applying a full frequency reuse to the base station Obtaining information on an outage probability that communication between the terminal and the base station, which varies according to the signal-to-noise ratio at the terminal, is to be interrupted for each of cases of applying the partial frequency reuse, The total frequency reuse and the partial frequency reuse, If as there the signal-to-noise ratio is lower the first frequency reuse scheme is changed to a first frequency reuse scheme and other second frequency reuse scheme, and a step of determining the direction of movement of the boundary on the basis of the change.

A boundary in a cellular network according to an embodiment of the present invention for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station A method for determining a movement direction comprises the steps of: acquiring information on a data transmission rate between a terminal and a base station and information on a signal-to-noise ratio in the terminal; and, when applying the entire frequency reuse to the base station, A first stop probability that the communication between the terminal and the base station changes depending on a signal-to-noise ratio and an outage probability which varies according to a signal-to-noise ratio in the terminal when partial frequency reuse is applied to the base station; Obtaining a second interruption probability that communication between the base stations will be interrupted; And the intersection of the first reference stop probability of the second stop probability and a step of determining the direction of movement of the boundary on the basis of the direction of travel, as the data transfer rate changes.

According to an embodiment of the present invention, in order to efficiently use the entire frequency reuse and partial frequency reuse adaptively based on a data transmission rate that varies depending on a transmission power of a base station, Can be determined. Therefore, by applying the entire frequency reuse or partial frequency reuse in the cell of the base station, it is possible to reduce the range in which the stop probability is lowered.

1 is a diagram illustrating a wireless communication system to which a boundary movement direction determination device in a cellular network according to an embodiment is applied.
2 is a diagram conceptually showing an entire frequency reuse region and a partial frequency reuse region in a cell of a base station.
3 is a diagram illustrating a configuration of a boundary movement direction determination device in a cellular network according to an embodiment of the present invention.
4 is a graph for explaining how the probability of interruption acting on a mobile station changes as the transmission power of the base station changes and the data transmission rate of the mobile station changes.
FIG. 5 is a graph illustrating a change in the probability of a stoppage of a base station as a data transmission rate is changed over a threshold value.
FIG. 6A and FIG. 6B conceptually illustrate the movement of a boundary for distinguishing each frequency reuse region so that the entire frequency reuse and partial frequency reuse can be efficiently used as the data transmission rate of the base station changes.
7 is a diagram illustrating a procedure of a boundary movement direction determination method in a cellular network according to an exemplary embodiment.
8 is a diagram illustrating a procedure of a boundary movement direction determination method in a cellular network according to another embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, To fully disclose the scope of the invention to a person skilled in the art, and the scope of the invention is only defined by the claims.

In describing embodiments of the present invention, a detailed description of well-known functions or constructions will be omitted unless otherwise described in order to describe embodiments of the present invention. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

The functional blocks shown in the drawings and described below are merely examples of possible implementations. In other implementations, other functional blocks may be used without departing from the spirit and scope of the following detailed description. Also, while one or more functional blocks of the present invention are represented as discrete blocks, one or more of the functional blocks of the present invention may be a combination of various hardware and software configurations that perform the same function.

Also, to the extent that the inclusion of certain elements is merely an indication of the presence of that element as an open-ended expression, it should not be understood as excluding any additional elements.

Further, when a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it should be understood that there may be other components in between.

Also, the expressions such as 'first, second', etc. are used only to distinguish a plurality of configurations, and do not limit the order or other features between configurations.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a wireless communication system 10 to which a boundary movement direction determination apparatus 100 in a cellular network according to an embodiment is applied.

Referring to FIG. 1, a wireless communication system 10 includes a boundary movement direction determination apparatus 100, a base station 200, a terminal 300, and a network 400 in a cellular network. However, the boundary movement direction determination apparatus 100 in the cellular network according to the embodiment is not construed to be limited to the wireless communication system 10 shown in FIG.

First, the terminal 300 communicates with the base station 200 using a frequency allocated to the base station 200 at a specific data transmission rate. At this time, the base station 200 can change the frequency reuse area and the data transmission rate. Here, since the terminal 300, the base station 200, and the cell 210 provided with the communication service by the base station 200 are self-explanatory concepts in the mobile communication field, detailed description thereof will be omitted.

In the cell 210, a cell to which the UE 300 belongs is called a serving cell, and a base station providing communication service to such a serving cell is called a serving base station. In addition, a cell adjacent to a serving cell is referred to as a neighboring cell, and a base station providing communication service to such a neighboring cell is referred to as a neighboring base station.

Meanwhile, according to the fractional frequency reuse (FFR) scheme, the cell 210 of the base station 200 is divided into a full frequency reuse region and a partial frequency reuse region. 2 is a diagram conceptually showing an entire frequency reuse area and a partial frequency reuse area in a cell 210 of the base station 200. As shown in FIG. In FIG. 2, Nf denotes a frequency reuse degree. When Nf is 3, it means that the partial frequency is reused by dividing the entire frequency spectrum into three parts. If Nf is 1, it means that the entire frequency is reused.

As shown in FIG. 2, when three cells 210 are present by three base stations 200, according to a fractional frequency reuse (FFR) scheme, when a terminal 300 is located at the center of a serving cell The entire frequency reuse scheme is applied near the center of the serving cell because the possibility of a crosstalk failure is small because the UE 300 is locally spaced from the adjacent base station. However, as the position of the UE 300 approaches the adjacent base station, 300 and the serving base station increases, the partial frequency reuse method is applied to the edge of the serving cell.

Therefore, it is important to define the boundary between the area to which the entire frequency reuse is applied and the area to which the partial frequency reuse is applied in the cell 210 so that the probability of interruption acting on the terminal in the cell 210 is minimized. However, if the transmission power of the base station 200 is changed, the change of the stop probability depending on the signal-to-noise ratio also changes. Therefore, the boundary between the area to which the entire frequency reuse is applied and the area to which the partial frequency reuse is applied must also be changed It is possible to reduce the probability of interruption.

When the transmission power of the base station 200 is changed, the boundary movement direction determination device 100 in the cellular network applies a partial frequency reuse area and an area for applying the entire frequency reuse to reduce the probability of interruption acting on the terminal 300 The direction in which the boundary of the region to be moved should be moved. At this time, all base stations 200 may have the same ratio of transmission power.

At this time, the boundary movement direction determination apparatus 100 in the cellular network classifies each frequency reuse area so that the entire frequency reuse and partial frequency reuse can be efficiently used based on the characteristic that the change in the transmission power is proportional to the change in the data transmission rate The direction in which the boundary moves.

The boundary movement direction determination apparatus 100 in the cellular network is connected to the base station 200 via the network 400. [ The network 400 may be a wired communication network 400, such as a LAN, or a wireless communication network 400, such as CDMA, 3G, 4G, LTE-A, or the like. However, the boundary movement direction determination apparatus 100 in the cellular network is connected to the base station 200 through the network 400, and the scope of the present invention is not limited thereto. For example, the boundary movement direction determination device 100 in the cellular network may be embodied to be included in each base station 200, unlike the one shown in FIG.

3 is a diagram illustrating a configuration of a boundary movement direction determination apparatus 100 in a cellular network according to an embodiment of the present invention. Referring to FIG. 3, the boundary movement direction determination apparatus 100 in the cellular network includes a basic information obtaining unit 110, a probability information obtaining unit 130, and a control unit 150. However, the present invention is not limited to the configuration shown in FIG. In addition, such a frequency allocation device and the respective configurations included therein can be implemented by a memory for storing an instruction programmed to perform the functions described below, and a microprocessor for executing such an instruction.

The basic information obtaining unit 110 obtains basic information for calculating the termination probability. More specifically, the basic information obtaining unit 110 obtains information on a data transmission rate at which data is transmitted between the terminal 300 and the base station 200. At this time, since the change of the data transmission rate is proportional to the change of the transmission power of the base station 200, it is possible to predict the change of the transmission power of the base station 200 by acquiring the change of the data transmission rate of the terminal 300. This information can be received, for example, from the base station 200 or the terminal 300 and acquired.

Also, the basic information obtaining unit 110 obtains information on the signal-to-noise ratio in the terminal 300. [ The signal-to-noise ratio in the terminal 300 is calculated on the basis of the signal and noise received from the serving cell 210 and the adjacent cell 210 by the terminal 300 in the serving cell 210. [ Information on the signal-to-noise ratio can be obtained, for example, from the base station 200 or the terminal 300. [

The probability information acquiring unit 130 acquires information on an abort probability at which the value changes as the signal-to-noise ratio changes. The probability information obtaining unit 130 further obtains information on the probability of interruption at the changed data transmission rate when the data transmission rate is changed.

At this time, the stop probability varying according to the change of the signal-to-noise ratio can be expressed by Equation 1 below.

는 단말(300)이 서빙 셀(210)의 기지국(200)을 기준으로 갖는 위치를 정규화한 파라미터이며,

는 단말(300)이 각각의 인접 셀(210)로부터 전달받은 신호 세기가 인접 셀(210)의 기지국(200)으로부터의 거리에 따라서 감쇄되는 정도를 나타내는 파라미터이다. Ncell은 모든 기지국(200)의 개수를 나타내고, W는 서빙 셀(210)의 기지국(200)이 지원하는 대역폭을 나타낸다. 여기서 수학식 1, 즉 신호 대 잡음비에 따라 변화하는 중단 확률에 대한 수식은 이미 공지된 기술이므로 이를 도출하는 과정 및 해당 수식에 대한 자세한 설명은 생략하기로 한다.Here, r is a signal-to-noise ratio in the horizontal axis of the graph in Fig. Nf is the frequency reuse factor described above with reference to FIG. 2. The value of Nf in case of full frequency reuse is greater than 1 when the value is 1 and partial frequency reuse. R represents the data transmission rate between the base station 200 and the terminal 300.

Is a parameter obtained by normalizing the position of the terminal 300 with respect to the base station 200 of the serving cell 210,

Is a parameter indicating the degree to which the terminal 300 attenuates the signal strength received from each neighboring cell 210 according to the distance from the base station 200 of the adjacent cell 210. [ Ncell represents the number of all base stations 200 and W represents the bandwidth supported by the base station 200 of the serving cell 210. [ Here, the formula for the stop probability varying according to Equation (1), i.e., the signal-to-noise ratio, is a known technique, and thus a detailed description of the process and derivation thereof will be omitted.

4 is a graph for explaining how the probability of interruption acting on the terminal 300 changes as the transmission power of the base station 200 changes and the data transmission rate of the terminal 300 changes. On the other hand, the stop probability in the entire frequency reuse is derived by substituting 1 into Nf in Equation (1), and the stop probability in the partial frequency reuse can be obtained by substituting a corresponding value exceeding 1 in Nf in Equation (1). 4, f is drawn by the formula derived from Equation (1) when 1 is substituted for Nf, and p is drawn by the formula derived from Equation (1) when a value exceeding 1 is assigned to Nf. At this time, the graph on the left side of FIG. 4 shows the data transmission rate as R1, and the graph on the right shows the data transmission rate as R2, where R2 has a transmission rate higher than R1.

R + is a data transmission rate at which the interruption probability starts to converge to a specific value. When the data transmission rate has a value of R + or more, when the entire frequency reuse and partial frequency reuse are used as shown in the right graph of FIG. 5, The probability of interruption can not be lowered.

Referring to FIG. 4, the degree of change of the stop probability when the entire frequency reuse is different from the degree of change of the stop probability when the partial frequency reuse occurs. For example, as to the degree to which the probability of interruption decreases when the signal-to-noise ratio increases, the decreasing rate is larger than in the case of partial frequency redistribution (p), as shown in FIG.

The control unit 150 determines the direction of movement of the boundary for distinguishing each frequency reuse region so that the entire frequency reuse and the partial frequency reuse can be efficiently used based on the stop probability that varies as the data transmission rate varies.

In order to achieve the target stopping probability during the entire frequency reuse and partial frequency reuse, the controller 150 according to an exemplary embodiment of the present invention performs a first frequency reuse method in which the first frequency reuse method having a lower signal- 2 frequency reuse method, the direction of movement of the boundary can be determined.

)을 달성함에 있어, R1의 데이터 전송 속도에서는 전체 주파수 재사용(f)이 부분 주파수 재사용(p)에 비해 낮은 SNR 값에서 타겟 중단 확률(

)을 달성할 수 있으므로 전체 주파수 재사용이 부분 주파수 재사용에 비해 유리하다. Referring again to FIG. 4,

), At the data transmission rate of R1, the total frequency reuse (f) is lower than the partial frequency reuse (p) at the target SNR value

), The total frequency reuse is more advantageous than partial frequency reuse.

)을 달성함에 있어, R2의 데이터 전송 속도에서는 부분 주파수 재사용(p)이 전체 주파수 재사용(f)에 비해 낮은 SNR 값에서 타겟 중단 확률(

)을 달성할 수 있으므로 부분 주파수 재사용이 전체 주파수 재사용에 비해 유리하다.At this time, when the data transmission rate from R1 to R2 is increased, the same target stop probability (

), At the data transmission rate of R2, the partial frequency reuse (p) is lower than the total frequency reuse (f) at the target SNR value

), Partial frequency reuse is more advantageous than overall frequency reuse.

)을 달성함에 있어 SNR을 줄일 수 있기 때문에 유리하다. If the data rate is increased while the terminal 300 exists in the same position, the terminal 300 applies the entire frequency reuse and applies the partial frequency reuse,

) Is advantageous because the SNR can be reduced.

This will be described with reference to FIGS. 6A and 6B in view of the cell 210. FIG. FIGS. 6A and 6B conceptually illustrate the movement of a boundary that divides each frequency reuse region so that the entire frequency reuse and partial frequency reuse can be efficiently used as the data transmission rate of the base station 200 changes.

이면서 데이터 전송 속도가 R1일 때, 기지국(200)으로부터 Ds 거리만큼 떨어져 있는 위치에 단말(300)이 존재하는 경우 해당 단말(300)에는 전체 주파수 재사용이 적용되는 영역이라고 가정한다. 이때 도 6b와 같이 기지국(200)의 전송 전력이

보다 큰

가 되어 데이터 전송 속도가 R2가 되면, 부분 주파수 재사용이 유리하므로 전체 주파수 재사용과 부분 주파수 재사용을 효율적으로 사용할 수 있도록 각 주파수 재사용 영역을 구분하는 경계를 셀(210)의 중심 쪽으로 이동시켜야 한다. Referring to FIG. 6A, when the transmission power of the base station 200 is

And a data transmission rate is R1 and a terminal 300 is located at a distance of Ds distance from the base station 200, it is assumed that the entire frequency reuse is applied to the corresponding terminal 300. At this time, as shown in FIG. 6B, the transmission power of the base station 200

Bigger

When the data transmission rate becomes R 2, the partial frequency reuse is advantageous. Therefore, the boundary for dividing each frequency reuse region must be shifted to the center of the cell 210 so that the entire frequency reuse and partial frequency reuse can be efficiently used.

)을 달성함에 있어, 데이터 전송 속도가 변화하여 전체 주파수 재사용보다 부분 주파수 재사용이 유리해지는 경우 경계가 셀(210)의 중심 쪽으로 이동해야 하는 것으로 판별할 수 있다. Accordingly, the control unit 150 determines whether or not the target stop probability

, It can be determined that the boundary must move toward the center of the cell 210 when the data transmission speed changes and the partial frequency reuse becomes more advantageous than the entire frequency reuse.

)을 달성함에 있어, 데이터 전송 속도가 변화하여 부분 주파수 재사용보다 전체 주파수 재사용이 유리해지는 경우 최적의 경계가 셀(210)의 가장자리 쪽으로 이동해야 하는 것으로 판별할 수 있다. In addition, the controller 150 determines whether the target stop probability

, It can be determined that the optimal boundary should move toward the edge of the cell 210 when the data transmission speed changes and the entire frequency reuse becomes more advantageous than the partial frequency reuse.

)이 데이터 전송 속도가 변화함에 따라 이동하는 방향을 기초로 경계의 이동방향을 판별할 수 있다. In addition, the control unit 150 according to another embodiment may determine a stop probability (hereinafter referred to as a 'first stop probability') that varies according to a signal-to-noise ratio in the UE 300 when the entire frequency reuse is applied as the SNR changes, ) And partial stopping probability (hereinafter referred to as 'second stop probability') which varies according to the signal-to-noise ratio in the terminal 300 when partial frequency reuse is applied

) As the data transmission speed changes, the moving direction of the boundary can be determined based on the moving direction.

)은 아래 수학식 2와 같다. The reference interruption probability at which the first interruption probability and the second interruption probability meet at the same data transfer rate is obtained by substituting a value obtained by substituting 1 into Nf in the expression (1) and n exceeding 1 in the expression (1) . Therefore,

) ≪ / RTI >

At this time, each factor constituting Equation (2) is the same as the factor of Equation (1), so that redundant explanation is omitted.

은 데이터 전송 속도 R의 변화에 따라 증감하는 함수로서, R이 R+ 미만일 때 R이 증가하면

의 값도 증가하며, R이 감소하면

의 값도 감소한다. On the other hand, referring to Equation (2)

Is a function of increasing or decreasing in accordance with the change of the data transmission rate R. When R is less than R + and R is increased

Is also increased, and when R decreases

Is also decreased.

,

)보다 높은 값을 가지는 중단 확률을 달성하기 위해서는 전체 주파수 재사용(f)이 유리하며, 기준 중단 확률(

,

) 보다 낮은 값을 가지는 중단 확률을 달성하기 위해서는 부분 주파수 재사용(p)이 유리하다. Referring again to FIG. 4,

,

), It is advantageous to use the entire frequency reuse (f) and the reference break probability (

,

, Partial frequency reuse (p) is advantageous in order to achieve a halt probability with a lower value.

)은 커진다. 예를 들어, 도 4에 도시된 바와 같이 데이터 전송 속도가 R1인 경우의 기준 중단 확률(

)보다 데이터 전송 속도가 R2인 경우의 기준 중단 확률

)이 더 크다. 따라서 타겟 중단 확률(

)을 달성함에 있어, 데이터 전송 속도가 커질수록 기준 중단 확률(

)이 타겟 중단 확률(

)보다 커지게 되므로 부분 주파수 재사용이 유리하며, 데이터 전송 속도가 작아질수록 기준 중단 확률(

)이 타겟 중단 확률(

)보다 작아지게 되므로 전체 주파수 재사용이 유리하다. At this time, according to Equation (2), as the data transmission rate increases,

). For example, as shown in FIG. 4, when the data transmission rate is R1, the reference interruption probability (

) ≪ / RTI > when the data transmission rate is R2

) Is larger. Therefore,

), The greater the data transmission rate, the more the reference interruption probability (

) Is the target stop probability (

), It is advantageous to reuse the partial frequency, and as the data transmission speed becomes smaller, the reference interruption probability (

) Is the target stop probability (

), So that the entire frequency reuse is advantageous.

)을 달성함에 있어 SNR을 줄일 수 있기 때문에 유리하다. When the data rate of the base station 200 increases while the terminal 300 is located at the same position based on this fact, it is determined that the terminal 300 applies the entire frequency reuse and applies the partial frequency reuse. Target drop probability (

) Is advantageous because the SNR can be reduced.

이면서 데이터 전송 속도가 R1일 때, 기지국(200)으로부터 Ds 거리만큼 떨어져 있는 위치에 단말(300)이 존재하는 경우 해당 단말(300)에는 전체 주파수 재사용이 적용되는 영역이라고 가정한다. 이때 도 6b와 같이 기지국(200)의 전송 전력이

보다 큰

가 되어 데이터 전송 속도가 R2가 되면, 부분 주파수 재사용이 유리하므로 전체 주파수 재사용과 부분 주파수 재사용을 효율적으로 사용할 수 있도록 각 주파수 재사용 영역을 구분하는 경계를 셀(210)의 중심 쪽으로 이동시켜야 한다. Referring to FIGS. 6A and 6B from the perspective of the cell 210, referring to FIG. 6A again, as described above, the transmission power of the base station 200

And a data transmission rate is R1 and a terminal 300 is located at a distance of Ds distance from the base station 200, it is assumed that the entire frequency reuse is applied to the corresponding terminal 300. At this time, as shown in FIG. 6B, the transmission power of the base station 200

Bigger

When the data transmission rate becomes R 2, the partial frequency reuse is advantageous. Therefore, the boundary for dividing each frequency reuse region must be shifted to the center of the cell 210 so that the entire frequency reuse and partial frequency reuse can be efficiently used.

)을 달성함에 있어, 데이터 전송 속도가 변화하여 기준 중단 확률(

)이 타겟 중단 확률(

)보다 높아지면 경계가 셀(210)의 중심 쪽으로 이동해야 하는 것으로 판별할 수 있다. Accordingly, the control unit 150 determines whether or not the target stop probability

), The data transfer rate changes and the reference interruption probability (

) Is the target stop probability (

, It can be determined that the boundary must move toward the center of the cell 210. [

)을 달성함에 있어, 데이터 전송 속도가 변화하여 기준 중단 확률(

)이 타겟 중단 확률(

)보다 낮아지면 경계가 셀(210)의 가장자리 쪽으로 이동해야 하는 것으로 판별할 수 있다. In addition, the controller 150 determines whether the target stop probability

), The data transfer rate changes and the reference interruption probability (

) Is the target stop probability (

, It can be determined that the boundary must move toward the edge of the cell 210. [

That is, since the change in the data transmission rate is proportional to the change in the transmission power of the base station 200, the entire frequency reuse and partial frequency reuse can be efficiently used based on the data transmission rate that varies depending on the transmission power of the base station 200 The direction in which the boundary dividing each frequency reuse region moves can be determined.

7 is a diagram illustrating a procedure of a boundary movement direction determination method in a cellular network according to an exemplary embodiment. Each step of the boundary movement direction determination method in the cellular network according to FIG. 7 can be performed by the boundary movement direction determination apparatus 100 in the cellular network described with reference to FIG. 3, Since each step is exemplarily shown, this method of determining the moving direction is not limited to the illustrated one. Each step will be described as follows.

Referring to FIG. 7, the step S710 of obtaining information on the data transmission speed between the terminal 300 and the base station 200 and the signal-to-noise ratio in the terminal 300 is performed.

Next, step S720 of obtaining information on the first stop probability and the second stop probability for the case of full frequency reuse and the case of partial frequency reuse at the data transmission rate is performed.

Next, a step S730 of determining the direction in which the optimum boundary moves based on the direction in which the reference interruption probability changes the data transmission speed is performed

In this case, the detailed operation method of each step overlaps with the description of the boundary movement direction determination device 100 in the cellular network described in FIGS. 1 to 6, and a detailed description thereof will be omitted below.

8 is a diagram illustrating a procedure of a boundary movement direction determination method in a cellular network according to another embodiment. Each step of the boundary movement direction determination method in the cellular network according to FIG. 8 can be performed by the boundary movement direction determination apparatus 100 in the cellular network described with reference to FIG. 3. At this time, Since each step is exemplarily shown, this method of determining the moving direction is not limited to the illustrated one. Each step will be described as follows.

Referring to FIG. 8, step S810 of obtaining information on a data transmission rate between the terminal 300 and the base station 200 and information on a signal-to-noise ratio in the terminal 300 is performed.

Next, a step S820 of obtaining information on the interruption probabilities for the entire frequency reuse case and the partial frequency reuse case is performed.

Next, in order to achieve a predetermined target stop probability, step S830 of discriminating the movement direction of the optimal boundary based on the direction in which the frequency reuse method with a lower signal-to-noise ratio is changed is performed

In this case, the detailed operation method of each step overlaps with the description of the boundary movement direction determination device 100 in the cellular network described in FIGS. 1 to 6, and a detailed description thereof will be omitted below.

According to the above-described embodiment, in order to efficiently use the entire frequency reuse and partial frequency reuse adaptively based on the data transmission rate that varies depending on the transmission power of the base station 200, Can be determined. Accordingly, since the moving direction of the boundary can be predicted, it is possible to reduce the range of searching the boundary where the stop probability is lowered by applying the entire frequency reuse or partial frequency reuse in the cell 210, The base station 200 can reset the boundary in the determined direction in order to efficiently use the FFR scheme.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs) , FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit is located inside or outside the processor, and can exchange data with the processor by various known means.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

100: Boundary movement direction discriminator in a cellular network
110: basic information obtaining unit
130: probability information obtaining unit
150:
200: base station
210: cell
300: terminal
400: Network

Claims (10)

An apparatus for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station,
A basic information obtaining unit for obtaining information on a data transmission rate between a terminal and the base station and information on a signal-to-noise ratio in the terminal;
Wherein, when the total frequency reuse is applied to the base station and the partial frequency reuse is applied to the base station at the data transmission rate, an interruption probability that the communication between the terminal and the base station, which varies according to a signal- a probability information obtaining unit that obtains information on an outage probability,
The method of claim 1, wherein, in achieving a predetermined target interruption probability, whether the frequency reuse scheme with the lower signal-to-noise ratio during the entire frequency reuse and the partial frequency reuse is changed from the overall frequency reuse scheme to the partial frequency reuse scheme, And a control unit for determining whether or not the entire frequency reuse scheme has been changed to the entire frequency reuse scheme and for determining a moving direction of the boundary based on a result of the determination
A boundary movement direction determination device in a cellular network. The method according to claim 1,
Wherein,
If the frequency reuse scheme having a lower signal-to-noise ratio is changed from the entire frequency reuse scheme to the partial reuse reuse scheme, it is determined that the boundary moves toward the center of the cell
A boundary movement direction determination device in a cellular network. The method according to claim 1,
Wherein,
If the frequency reusing scheme having a lower signal-to-noise ratio is changed from the partial frequency reuse scheme to the entire dominant reuse reuse scheme, it is determined that the boundary moves toward the edge of the cell
A boundary movement direction determination device in a cellular network. delete delete delete A method for determining a direction in which an optimal boundary moves between a full frequency reuse region and a partial frequency reuse region in a cell of a base station,
Acquiring information on a data transmission rate between a terminal and the base station and information on a signal-to-noise ratio in the terminal;
Wherein, when the total frequency reuse is applied to the base station and the partial frequency reuse is applied to the base station at the data transmission rate, an interruption probability that the communication between the terminal and the base station, which varies according to a signal- obtaining information on an outage probability of the user,
The method of claim 1, further comprising: determining whether a frequency reuse scheme having a lower signal-to-noise ratio is changed from the overall frequency reuse scheme to the partial frequency reuse scheme, Determining whether or not the entire frequency reuse method has been changed;
And determining a moving direction of the boundary based on the determined result
A method for determining boundary movement directions in a cellular network. delete 15. A computer program stored on a computer readable medium for causing a processor to perform the method of claim 7. 13. A computer-readable medium having recorded thereon a program for causing a processor to perform the method of claim 7.

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