KR102236261B1 - Apparatus and method for deciding boundary movement direction - Google Patents

Abstract

An apparatus for determining the boundary of an external region or an internal region in which a terminal exists within a cell of a base station includes a basic information acquisition unit that obtains basic information, and communication between the terminal and the base station is stopped through the basic information. And a probability information acquisition unit for obtaining an outage probability to be performed, and a control unit for adjusting the boundary by comparing the interruption probability with a predetermined target interruption probability.

Description

Boundary movement direction determination device and method {APPARATUS AND METHOD FOR DECIDING BOUNDARY MOVEMENT DIRECTION}

The present invention relates to an apparatus and method for determining a boundary movement direction, and more particularly, to determine a movement direction of a boundary that divides a frequency reuse area in a soft frequency reuse system as the transmission power of a base station is changed within a cell of the base station. It relates to an apparatus and a method for determining a boundary movement direction.

The wireless communication system after 3G requires a higher data rate than the conventional one, and accordingly, a multipath delay that causes inter-symbol interference (ISI) is a problem. Orthogonal Frequency Division Multiplexing (OFDM) is drawing attention as a technique for attenuating the aforementioned ISI.

Briefly looking at such OFDM, OFDM converts serially input data symbols into N parallel data symbols, and then carries them on separate N subcarriers and transmits them.These subcarriers have orthogonality in the frequency dimension. Each orthogonal channel experiences frequency selective fading independently from each other, and the interval of transmitted symbols becomes longer. Accordingly, ISI can be minimized.

Meanwhile, in a wireless communication system, a cell refers to subdividing an area where a communication service is provided into small areas in order to efficiently use a frequency. In general, a base station is installed in the center of such a cell.

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

The aforementioned inter-cell interference can be reduced by increasing soft frequency reuse. In this case, as the transmission power of the base station is changed, the direction in which the boundary dividing the entire frequency reuse region moves should be specified.

Korean Patent Registration Publication 10-1256226, registration date April 12, 2013

A problem to be solved in an embodiment of the present invention is to provide a technique for determining a moving direction of a boundary for dividing a frequency reuse region in a soft frequency reuse system according to a change in transmission power of a base station.

However, the technical problems to be achieved by the embodiments of the present invention are not limited to the above-mentioned problems, and various technical problems can be derived from the contents to be described below within a range that is obvious to a person skilled in the art.

In an apparatus for determining a boundary movement direction according to an embodiment of the present invention, in an apparatus for determining a boundary of an external region or an internal region in which a terminal exists within a cell of a base station, a basic information acquisition unit that obtains basic information And a probability information acquisition unit that obtains an outage probability at which communication between the terminal and the base station is stopped through the basic information, and a control unit that adjusts the boundary by comparing the interruption probability with a predetermined target interruption probability. Includes.

When the terminal is located in the external area, the control unit may adjust the boundary by comparing the interruption probability with the predetermined target interruption probability.

When the interruption probability is lower than the predetermined target interruption probability, the controller may move the boundary toward the edge of the cell so that the terminal is located in the inner area.

The control unit may not adjust the boundary when the terminal is located in the inner area.

The basic information may include at least one of a transmission power, a data transmission rate, and a data transmission rate between the base station and the terminal.

The frequency of the inner region and the frequency of the outer region may be different from each other.

The cell may be adjacent to a plurality of cells, and the frequencies of the outer region of the cell and the plurality of adjacent cells may all be different.

In the method of determining a boundary movement direction according to an embodiment of the present invention, in a method of determining a boundary so that a terminal is located in an inner region or an external region within a cell of a base station, the transmission power between the terminal and the base station is Obtaining information about the transmission power, calculating an outage probability at which communication between the terminal and the base station will be interrupted based on the information on the transmission power, and comparing the interruption probability with a predetermined target interruption probability. And adjusting the boundary.

The step of adjusting the boundary may include moving the boundary toward the edge of the cell so that the terminal is located in the inner region when the terminal is located in the outer region and the interruption probability is lower than the predetermined target interruption probability. The boundary can be adjusted.

According to an embodiment of the present invention, as the transmission power of the base station is changed in the cell of the base station, the moving direction of the boundary for dividing the frequency reuse area in the soft frequency reuse system may be determined. Therefore, when examining where the boundary for minimizing the probability of interruption is within the cell of the base station, the effect of reducing the investigation range can be exerted according to an embodiment.

1 is a diagram illustrating a wireless communication system to which an apparatus for determining a boundary movement direction according to an embodiment is applied.
FIG. 2 is a diagram conceptually illustrating that when soft frequency reuse is applied to a cell of a base station, an inner area of each cell is divided by a boundary.
FIG. 3 is a more detailed view of some of the drawings shown in FIG. 2.
4 is a diagram showing a configuration of an apparatus for determining a boundary movement direction according to an embodiment of the present invention.
5A and 5B are diagrams illustrating graphs for explaining that the probability of interruption acting on the terminal is changed as the data transmission rate of the terminal is changed due to the change in transmission power of the base station.
6 is a diagram illustrating whether or not an area of a center region is increased or decreased according to a change in transmission power of a base station.
7 is a diagram illustrating a procedure of a method of determining a boundary movement direction according to an exemplary embodiment.

Advantages and features of the present invention, 　, and a method of achieving them will become apparent with reference to the embodiments described later in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. It is provided to fully inform the person of the scope of the invention, and the scope of the invention is only defined by the claims.

In describing the embodiments of the present invention, detailed descriptions of known functions or configurations will be omitted except when actually necessary in describing the embodiments of the present invention. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout the present specification.

The functional blocks shown in the drawings and described below are only examples of possible implementations. In other implementations, other functional blocks may be used without departing from the spirit and scope of the detailed description. Also, while one or more functional blocks of the present invention are represented as individual 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.

In addition, the expression to include certain elements is an open expression, merely refers to the existence of the corresponding elements, and should not be understood as excluding additional elements.

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

In addition, expressions such as'first, second', etc. are used only for distinguishing a plurality of elements, and do not limit the order or other features between the elements.

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

1 is a diagram illustrating a wireless communication system 10 to which an apparatus 100 for determining a boundary movement direction according to an exemplary embodiment is applied.

Referring to FIG. 1, a wireless communication system 10 includes an apparatus 100 for determining a boundary movement direction, a base station 200, a terminal 300, and a network 400. However, it is not interpreted that the apparatus 100 for determining the boundary movement direction according to an embodiment is limited to the wireless communication system 10 illustrated in FIG. 1.

First, the terminal 300 communicates with the base station 200 at a specific data transmission rate using a frequency allocated to the base station 200. In this case, the base station 200 may change the frequency reuse region and the data transmission rate. Here, the terminal 300, the base station 200, and the cell 210 provided with a communication service by the base station 200 is a self-evident concept in the mobile communication field, and thus a detailed description thereof will be omitted.

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

On the other hand, according to the soft frequency reuse method, the inside of the cell 210 of the base station 200 is divided into an inner area and an outer area. In this case, the inner area and the outer area are divided by'boundaries'.

2 is a diagram conceptually showing that the inside of the cell 210 of the base station 200 is divided into an inner area and an outer area.

Referring to FIG. 2, a plurality of different frequencies are allocated to an inner region of each cell 210, and a different frequency from that allocated to the inner region of each cell is allocated to an outer region of each cell. In addition, when looking at any one cell 210, the frequency allocated to the outer region of the cell 210 is different from the frequency allocated to the outer region of the cell 210 disposed adjacent to the cell 210. In addition, as shown in FIG. 2, the frequencies allocated to the inner region may be divided into two. For example, the frequency F1 and the frequency F2 may be allocated to the inner region of cell 0, and the frequency F3 and the frequency F2 may be allocated to the inner region of cell 1.

This can also be confirmed in FIG. 3. FIG. 3 exemplarily shows how frequencies are allocated to each cell 210. 3, the frequency of the inner region of cell A is F2 + F3, the frequency of the outer region of cell A is F1, the frequency of the inner region of cell B is F1 + F3, but the frequency of the outer region of cell B is F2, and the frequency of the inner region of cell C is F1 + F2, but the frequency outside cell B is F3. That is, the frequencies allocated to the outer regions of cells arranged adjacent to each other are different from each other, and the frequencies allocated to the inner region and the frequencies allocated to the outer region are different from each other. 3 illustrates that the shape of the inner region is hexagonal, but the present invention is not limited thereto, and the inner region of each cell 210 may be circular as shown in FIG. 2 or may have a different shape.

On the other hand, the inner area and the outer area are divided by a'boundary', and the probability of interruption acting on the terminal in the cell 210 may vary depending on where the border is located. At this time, if the transmission power of the base station 200 changes, the above-described change in the interruption probability may also change. Accordingly, the position of the boundary or the movement aspect of the boundary must be determined in consideration of the change in transmission power of the base station 200.

Accordingly, when the transmission power of the base station 200 is changed, the boundary movement direction determination apparatus 100 according to an embodiment moves the position or the boundary of the aforementioned boundary to reduce the probability of interruption acting on the terminal 300. It is configured to determine the direction to be taken. In this case, it is assumed that the rate at which the transmission power varies in all the base stations 200 may be the same.

The boundary movement direction determination apparatus 100 is connected to the base station 200 through 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, it is only exemplary that the apparatus 100 for determining the boundary movement direction is connected to the base station 200 through the network 400, and the spirit of the present invention is not limited thereto. For example, the apparatus 100 for determining the boundary movement direction may be implemented to be included in each base station 200 unlike that shown in FIG. 1.

4 is a diagram showing a configuration of an apparatus 100 for determining a boundary movement direction according to an embodiment of the present invention. Referring to FIG. 4, the apparatus 100 for determining a boundary movement direction includes a basic information acquisition unit 110, a probability information acquisition unit 130, and a control unit 150. However, it is not construed as limited to the configuration shown in FIG. 4. In addition, the frequency allocation apparatus and each of the components included therein may be implemented by a memory storing instructions programmed to perform a function to be described below, and a microprocessor executing these instructions.

The basic information acquisition unit 110 acquires basic information for calculating a discontinuation probability. In more detail, the basic information acquisition unit 110 receives transmission power of the base station 200. In addition, the change in transmission power and the data transmission rate at which data is transmitted between the terminal 300 and the base station 200 are proportional. Accordingly, when the transmission power of the base station 200 is high, the data transmission rate increases, and accordingly, the data transmission rate increases. Such information may be obtained by receiving, for example, from the base station 200 or the terminal 300.

The probability information acquisition unit 130 obtains a stop probability of each of the inner region and the outer region within the cell 210 based on the acquired basic information. The interruption probability is proportional to the data transmission rate and the transmission power. When the transmission power of the base station 200 is high, the interruption probability decreases, and when the transmission power is low, the interruption probability increases.

At this time, since the interruption probability that changes as the transmission power changes can be expressed by a known equation, the equation for the interruption probability will be omitted.

5A and 5B are diagrams illustrating graphs for explaining that the probability of interruption acting on the terminal 300 varies as the transmission power of the base station 200 is changed. In particular, it is shown that the interruption probability of the inner region and the outer region changes according to the transmission power.

5A and 5B, as the transmission power of the base station 200 changes, Case 1 in which the probability of interruption changes as shown in FIG. 5A, and Case 2 in which the probability of interruption changes as illustrated in FIG. 5B. There may be.

Looking at each case, first, in each case, the area in which the terminal 300 is located may be changed from an external area to an inner area, but the opposite is not possible.

More specifically, it can be seen from FIG. 5A that as the transmission power of the base station 200 increases, the probability of stopping the terminal 300 decreases, and the area in which the terminal 300 is located is changed from an external area to an internal area.

In addition, similarly to FIG. 5B, it can be seen that as the transmission power of the base station 200 increases, the probability of interruption of the terminal 300 decreases, and the area in which the terminal 300 is located is changed from the outer area to the inner area.

That is, in an embodiment, as the transmission power increases as the data transmission rate increases, the probability of interruption decreases, and accordingly, the boundary area changes, so that the terminal 300 in the external area may enter the inner area. That is, it is determined whether the probability of interruption when the terminal 300 is in an area between the inner area and the outer area is relatively small, and accordingly, the location of the border or the direction of movement of the border may be determined.

In achieving the target interruption probability (p`), the control unit 150 moves the boundary toward the edge of the cell 210 when it becomes more advantageous to position the terminal 300 in the inner region rather than the outer region due to the change in the transmission power. It can be determined what should be done. The target interruption probability (p`) may be a probability determined by the user or may be appropriately set by the boundary movement direction determining apparatus 100 itself. Accordingly, the control unit 150 adjusts the boundary of the inner area so that the terminal 300 is located in the inner area. Referring to FIG. 6, when the terminal 300 is in the external region, when the transmission power increases and the interruption probability is lower than the target interruption probability p`, the boundary is expanded and the terminal 300 is located in the internal region. .

As described above, according to an embodiment, as the transmission power of the base station is changed within the cell of the base station, the moving direction of the boundary for dividing the frequency reuse region in the soft frequency reuse system may be determined. Accordingly, when examining where the boundary for minimizing the probability of interruption is within the cell of the base station, the effect of reducing the investigation range can be exerted according to an embodiment.

7 is a diagram illustrating a procedure of a method of determining a boundary movement direction according to an exemplary embodiment. Each step of the boundary movement direction determination method according to FIG. 7 may be performed by the boundary movement direction determination apparatus 100 described through FIG. 4, wherein each step included in the movement direction determination method is illustrated by way of example. Therefore, the method of determining the moving direction is not limited to that shown. Meanwhile, each step will be described as follows. In this case, since the detailed method of performing each step is duplicated with the description of the apparatus 100 for determining the boundary movement direction described in FIGS. 1 to 5, a detailed description thereof will be omitted below.

First, basic information is obtained (S710). It has been described above that the basic information may include transmission power and data rate, and these information can be received through the base station 200 or the terminal 300.

Subsequently, the probability of stopping is obtained through the basic information (S720). However, since it is impossible to change to the external region when the terminal 300 is in the internal region, the probability of interruption is obtained when the terminal 300 is in the external region.

Subsequently, when the stopping probability of the terminal 300 in the outer rudr area is lower than the predetermined target stopping probability, the boundary is moved toward the edge to adjust the boundary so that the terminal 300 is located in the inner area (S730).

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

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

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

As such, those skilled in the art to which the present invention pertains will be able to understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the embodiments described above are illustrative in all respects and should be understood as non-limiting. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. .

100: boundary movement direction determination device
110: basic information acquisition unit
130: probability information acquisition unit
150: control unit
200: base station
210: cell
300: terminal
400: network

Claims (11)

In the apparatus for determining the boundary of an external region or an internal region in which a terminal exists within a cell of a base station,
A basic information acquisition unit that acquires basic information,
A probability information acquisition unit that obtains an outage probability at which communication between the terminal and the base station is stopped through the basic information,
Comprising a control unit for adjusting the boundary by comparing the interruption probability with a predetermined target interruption probability,
The control unit,
When the terminal is located in the external area, the boundary is adjusted by comparing the interruption probability with the predetermined target interruption probability,
If the interruption probability is lower than the predetermined target interruption probability, the boundary is moved toward the edge of the cell so that the terminal is located in the inner area,
If the terminal is located in the inner area, the boundary is not adjusted
Boundary movement direction determination device.
delete delete delete The method of claim 1,
The basic information is,
Including at least one of transmission power, data rate, and data rate between the base station and the terminal
Boundary movement direction determination device. The method of claim 1,
The frequency of the inner region and the frequency of the outer region are different from each other
Boundary movement direction determination device. The method of claim 1,
The cell is adjacent to a plurality of cells,
All frequencies of the outer region of the cell and the plurality of adjacent cells are different
Boundary movement direction determination device. In a method for determining a boundary so that a terminal is located in an inner area or an outer area within a cell of a base station,
Obtaining information on transmission power between the terminal and the base station,
Calculating an outage probability at which communication between the terminal and the base station is stopped based on the information on the transmission power; and
Comprising the step of comparing the interruption probability with a predetermined target interruption probability and adjusting the boundary,
The adjusting step,
When the terminal is located in the outer region and the interruption probability is lower than the predetermined target interruption probability, the boundary is moved to the edge of the cell, and the boundary is adjusted to position the terminal in the inner region, and the terminal Including the step of not adjusting the boundary if it is located in the inner region
How to determine the direction of boundary movement. delete A computer program stored in a computer-readable recording medium for causing a processor to perform the method of claim 8. A computer-readable recording medium on which a program including instructions for causing a processor to perform the method of claim 8 is recorded.

Images