KR20190038132A - Method and Apparatus for Configuration of Link Based on Time Division Duplex for Controlling Inter-Cell Interference - Google Patents

Abstract

Disclosed are a method for configuring a link based on TDD to control inter-cell interference and an apparatus therefor. More specifically, the method for configuring a link based on TDD to control inter-cell interference and the apparatus therefor are for measuring interference between cells using TDD, setting layers to minimize the interference between the cells, and adjusting uplink/downlink configuration for each layer.

Description

[0001] The present invention relates to a TDD-based link configuration method for controlling inter-cell interference, and a device for the link configuration method.

This embodiment relates to a TDD-based link configuration method for controlling inter-cell interference and an apparatus therefor.

The contents described in this section merely provide background information on the present embodiment and do not constitute the prior art.

The mobile communication system uses a duplex technique for downlink (DL) and uplink (UL) services. Duplex technology can be roughly classified into a Frequency Division Duplex (FDD) method and a Time Division Duplex (TDD) method.

In the case of the FDD method, the frequency band for the DL and the frequency band for the UL are fixedly allocated and used. Since the use of the frequency band can not be changed, even if the DL traffic increases, it is difficult to take special measures.

On the other hand, in the case of the TDD scheme, DL and UL can be allocated and used in units of subframes in one frame by using the same frequency band variablely assigned to DL or UL according to time.

As described above, the TDD scheme can increase the traffic acceptance efficiency of the network by adjusting the resource allocation ratio corresponding to the change of DL or UL traffic.

In the TDD scheme, the DL and UL configurations can be set differently according to the service environments required for each unit such as a cell, a cluster, and the like. However, in an actual network environment, It is difficult to use because of the influence.

For example, when the uplink / downlink configuration is set differently for each predetermined unit in the TDD scheme, since the same frequency is used, the B base station 111, which is a peripheral base station, The downlink signal of the B base station 111 is received by the A base station 110 and acts as an interference and quality degradation occurs in the A base station 110 and the B base station 111. [ For this reason, in general, in the TDD scheme, the uplink / downlink configurations of all the base stations included in the predetermined area are equalized to prevent mutual interference. However, the TDD scheme that matches the uplink / downlink configuration equally degrades the traffic acceptance efficiency of the network.

Therefore, there is a need for a method that can minimize the interference between cells (local area, local area) in the TDD scheme and apply the setting of uplink / downlink configuration as needed.

In this embodiment, a TDD-based link is used for measuring inter-station interference using the TDD scheme, setting up a layer for minimizing interference between local stations, and controlling inter-cell interference for adjusting up / A method for constructing the same, and a device therefor.

According to an aspect of the present invention, there is provided an apparatus for minimizing interference between a plurality of base stations using a TDD (Time Division Duplex) scheme, the apparatus comprising: A local extracting unit for extracting a local region; Downlink configuration (DL) of the target local station and changing the uplink / downlink configuration (DL) of the local station to minimize the interference between the target local station and the neighboring local station based on the target local station. And an interference control unit for adjusting the set value of the cell control unit.

According to another aspect of the present invention, there is provided a method of minimizing interference between a plurality of base stations using a TDD (Time Division Duplex) scheme, the method comprising: A local extraction process for extracting a target locus where this occurs; Downlink configuration (DL) of the target local station and changing the uplink / downlink configuration (DL) of the local station to minimize the interference between the target local station and the neighboring local station based on the target local station. And an interference control step of adjusting a set value of the TDD-based link.

As described above, according to the present embodiment, the cell control apparatus has the effect of setting up different uplink / downlink configurations for each of a plurality of stations in order to minimize interference between stations.

In addition, according to the present embodiment, it is possible to maximize the traffic acceptance efficiency of the network by configuring different uplink / downlink configurations for each of a plurality of stations, and it is possible to utilize the network to satisfy various service requirements have.

1 is a diagram schematically showing a communication system according to the present embodiment.
2 is a block diagram schematically showing a cell control apparatus according to the present embodiment.
FIGS. 3A and 3B are views illustrating an operation for setting a frame and a layer for minimizing interference between cells according to the present embodiment.
4 is a flowchart illustrating an operation method of a cell control apparatus for minimizing interference between cells according to the present embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that the term "Quot;, " module ", and " module " refer to a unit that processes at least one function or operation, and may be implemented by hardware or software or a combination of hardware and software.

The present embodiment can be applied to a mobile communication system (Evolved Packet System or Long Term Evolution System) operating on 3GPP standards. For example, the present embodiment can be applied to a next generation mobile / wireless communication system based on a next generation wireless communication system (e.g., a fifth generation system) or another communication system as well as a LTE (Long Term Evolution) System.

1 is a diagram schematically showing a communication system according to the present embodiment.

The communication system 100 according to this embodiment includes a plurality of base stations 110, 111, 112, 113, 114, 115 and 116, a plurality of cells 120, 121, 122, 123, 124, And a terminal (not shown) of the communication system 100. The communication system 100 represents a system in which a plurality of cells in which overlapping areas exist coexist.

As shown in FIG. 1, in a network environment in which a plurality of cells coexist, interference may occur between adjacent cells if the distance between cells is close to each other. The plurality of cells shown in FIG. 1 may be a macro cell, but may be a small cell such as a picocell or a femtocell for increasing the transmission capacity per unit area through frequency reuse, It is also possible that a cell and a small cell are mixed.

The communication system 100 according to the present embodiment assumes that each cell adopts a time division duplex (TDD) scheme in a network environment in which a plurality of cells are concentrated or coexist. Here, if the communication system 100 can employ the TDD scheme, it may be a form of a coexistence network in which the TDD scheme and the FDD scheme coexist. In the case of the TDD scheme, the same frequency band is allocated to a DL (Downlink) or an UL (UL) in a time-wise manner, and the downlink and uplink are allocated and used in units of subframes in one frame have.

The TDD scheme can increase the traffic acceptance efficiency of the network by setting different settings of the DL and UL configurations according to the service environments required for each unit such as a cell and a cluster, In actual network environment, it is difficult to use due to the influence of interference.

1, when a plurality of base stations 110, 111, 112, 113, 114, 115, and 116 installed in the communication system 100 use uplink / downlink configuration settings differently, Interference occurs between the first base station 110 and the neighboring base stations 111, 113, 115, and 116 because the downlink signals are mixed.

In this embodiment, the 4G system and the 5G system can reflect various requirements of the related service function in addition to the technical development, and the enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC) Type Communication, which can support a variety of services such as network configuration (Network Configuration) can be supported in terms of efficient configuration of uplink / downlink configuration is proposed.

2 is a block diagram schematically showing a cell control apparatus according to the present embodiment.

The cell control apparatus 200 according to the present embodiment includes an information collecting unit 210, a coverage map generating unit 220, a local extracting unit 230, and an interference controlling unit 240. The cell control device 200 shown in FIG. 2 is according to one embodiment. Not all the blocks shown in FIG. 2 are essential components, and in some embodiments, some blocks included in the cell control device 200 are added , Changed or deleted.

The cell control apparatus 200 measures interference of a local station (cell, base station, cluster, etc.) using the TDD scheme, and controls setting of a layer setting and an uplink / downlink configuration for minimizing interference between stations. The cell control apparatus 200 may be a wireless network design and analysis system interworking with an LTE, an LTE-Advanced system, an LTE-Advanced pro system, a fifth generation system, etc., but is not limited thereto and may be provided in a macro cell or a small- Or may be implemented as an external server.

The information collecting unit 210 collects radio resource information for each of a plurality of base stations located within a predetermined area.

The information collecting unit 210 collects radio resource information such as location information, configuration information, and beam information from each base station. Here, the location information may include information on the location where the base station is installed, and may include information on latitude, longitude, altitude, etc., and the configuration information may include shape information of the base station, effective information radiated power (ERP) And Equivalent Isotropic Radiated Power (EIRP) information. Also, the beam information may include information such as a direction angle of the antenna, a beam width, an ANT gain, a beam pattern, and the like.

The information collecting unit 210 may receive the radio resource information transmitted from each base station at a predetermined period or at a predetermined time, but the present invention is not limited thereto. The radio resource information Can be obtained.

The coverage map generator 220 generates a coverage map for each subscriber based on the radio resource information collected from the base station.

The coverage map generating unit 220 may generate a local coverage map including at least one base station, but is not limited thereto, and may be implemented with a coverage map for each base station.

The coverage map generator 220 generates a coverage map to determine inter-station interference, and the generated coverage map can be kept up-to-date, i.e., continuously updated, using the radio resource information periodically collected.

The local extractor 230 measures inter-station interference using the coverage map, and selects a target region to which the UL configuration is to be changed due to the occurrence of interference. Specifically, the local extractor 230 derives localities that are determined to have inter-cell interference greater than a predetermined interference threshold based on the coverage map to generate a local list, and performs a UL (UL) ) Is selected. Here, it is preferable that the local extracting unit 230 selects the local region having the highest interference measurement value among the local list as the target local region, but the present invention is not limited thereto.

The local extractor 230 measures inter-station interference in which cell coverage is overlapped and determines whether to change the uplink / downlink configuration of a target station based on a predetermined interference threshold. That is, the local extractor 230 compares the measured interference measurement value with a predetermined interference threshold value, and selects a local station that exceeds the interference threshold as a target station for changing the uplink / downlink configuration. Here, the local extractor 230 may measure the interference of at least one of the uplink interference and the downlink interference in measuring the inter-site interference. For example, the local extractor 230 may measure downlink interference between stations. The downlink interference can be measured by using a pilot signal having a unique pattern for each cell. When one of the cells transmits a pilot signal to the remaining cells, a cell transmitting the pilot signal in the remaining cells , And various other measurement methods can be applied.

The interference controller 240 changes the configuration of the uplink / downlink configuration of the target station and adjusts the uplink / downlink configuration for neighboring stations to minimize interference with neighboring stations based on the target station. The interference control unit 240 according to the present embodiment includes an interference measurement unit 242, a layer setting unit 244, and a link configuration setting unit 246. [

The interference controller 240 performs an operation to minimize the inter-site interference after changing the uplink / downlink configuration of the extracted target station. Here, the uplink / downlink configuration change of the target station may be performed by the link configuration setting unit 246, but the present invention is not limited thereto. It is assumed that the uplink / downlink configuration of the target station is changed, May be performed.

The interference measuring unit 242 checks whether interference occurs between a target local station and a neighboring local station based on a target station whose uplink / downlink configuration is changed, and extracts surrounding stations where interference occurs.

The interference measuring unit 242 compares the uplink / downlink configuration of the target station with the uplink / downlink configurations of the neighboring stations and detects the neighboring stations where the interference occurs when the interference between the target station and the neighboring stations exceeds a predetermined interference threshold value . Here, the neighboring local station in which the interference occurs may include a plurality of stations, and may include a plurality of cells or a base station.

On the other hand, when there is no neighboring station where interference occurs, the interference measuring unit 242 maintains the setting of the target station with the changed uplink / downlink configuration and the neighboring station with the existing uplink / downlink configuration.

The layer setting unit 244 derives the layer setting information for changing the uplink / downlink configuration of the neighboring stations according to the change of the uplink / downlink configuration of the target station. Here, the layer setting information may include the number of layers between the target local and peripheral stations, the link configuration setting values of the respective layers, and the like.

The layer setting unit 244 confirms the uplink / downlink configuration of the target station and the uplink / downlink configurations of the neighboring stations, and classifies the uplink / downlink configuration into at least one layer within the range between the target station and the neighboring stations And calculates a set value of the uplink / downlink configuration to be applied to each layer. For example, if the uplink / downlink configuration of the target station is 3 (downlink): 1 (uplink) and the uplink / downlink configuration of the neighboring station is 1 (downlink) The setting unit 244 generates one layer between a target local region and a neighboring local region, and the uplink / downlink configuration of the corresponding layer may be 2 (downlink): 1 (uplink).

The uplink / downlink configuration may be a ratio of uplink / downlink separately set for each of a plurality of stations. However, as shown in Table 1, one of the predetermined uplink / downlink configurations (conf.0 to conf. 6) . The uplink / downlink configuration can be applied based on the 3GPP LTE standard as shown in [Table 1], but the present invention is not limited thereto, and a configuration configuration based on the next generation wireless communication technology such as 3GPP 5G NR (New Radio) may be applied.

Subframe n: 0 One 2 3 4 5 6 7 8 9 conf. 0 D S U U U D S U U U conf. One D S U U D D S U U D conf. 2 D S U D D D S U D D conf. 3 D S U U U D D D D D conf. 4 D S U U D D D D D D conf. 5 D S U D D D D D D D conf. 6 D S U U U D S S U D

In Table 1, 'D' denotes a downlink subframe, 'U' denotes an uplink subframe, 'S' denotes a switching point (DwPTS + Guard Period + UpPTS (Uplink Pliot Time Slot) )).

The link configuration setting unit 246 changes the uplink / downlink configuration of the target local station. The link configuration setting unit 246 calculates a set value for changing the uplink / downlink configuration of the target local station, and transmits the calculated set value to the target station to change the uplink / downlink configuration of the target station.

On the other hand, the link configuration setting unit 246 applies up / down link configuration values to the generated layer to minimize interference between the target local and neighboring local stations. The link configuration setting unit 246 sets the link configuration setting unit 246 to the at least one base station included in the layer including some of the surrounding local stations based on the layer setting information based on the target local station Transfers the setting value.

The link configuration setting unit 246 changes the uplink / downlink configuration for the layer, and then transmits an additional interference measurement signal for further measuring the interference to the interference measurement unit 242, . Here, the further detected local station may be local according to the measurement result of the interference of the neighboring local station based on the hierarchy in which the uplink / downlink configuration is changed.

FIGS. 3A and 3B are views illustrating an operation for setting a frame and a layer for minimizing interference between cells according to the present embodiment.

Referring to FIG. 3A, the cell control apparatus 200 sets different UL (UL) configurations for regions other than the A region (or the A base station) and the A region. For example, the cell control apparatus 200 sets the uplink / downlink configuration of the A region (A base station) at a 3: 1 ratio, and the remaining regions except for the A region have a 1: 1 ratio. In this case, as shown in (b) of FIG. 3A, interference occurs in the Time 1/4 region between regions other than the A region and the A region.

In the actual network environment, when two base stations are adjacent to each other and interference signals are received, interference occurs due to the uplink / downlink configuration, so that different uplink / downlink configurations can not be established between adjacent base stations.

The cell control apparatus 200 according to the present embodiment extracts a neighbor base station at a position where interference occurs based on a predetermined base station (A base station). Here, the cell control apparatus 200 can extract a base station object that can interfere with neighboring base stations using configuration information, beam information, and the like for each base station. Here, the configuration information may include shape information of the base station, output information, equivalent isotropic radiated power (EIRP) information, etc., and the beam information may include information such as a direction angle, a beam width, an ANT gain, Information.

A neighbor base station at a location where interference occurs based on a predetermined base station (A base station) may be a base station located in a region B in (b) of FIG. 3B. In this case, if the base stations of the B region determined to generate the interference use the 1: 1 ratio of the uplink / downlink configuration, the 25% region which is the time 1/4 region is the interference region, If the downlink configuration is adjusted to a 2: 1 ratio, a region of about 16.5% is an interference region, and the region where interference occurs can be reduced. That is, according to (b) of FIG. 3B, as the uplink / downlink configuration of region B is changed, region C except for region A and region B uses the ratio of 1: 1, which is the existing uplink / downlink structure, Can be reduced.

The operation of the cell control device 200 according to the present embodiment will be summarized below with reference to FIG. 3B (a). In the TDD-based network environment in which the coverage of a plurality of base stations is superimposed, the cell control apparatus 200 according to the present embodiment sets the uplink / downlink configuration of the A region selected as the interference affected region as the first type, It is possible to minimize the interference by setting the uplink / downlink configuration to the multi-level hierarchical structure of the remaining area except the A area. For example, the cell control apparatus 200 sets the uplink / downlink configuration of the A area to the first type, sets the uplink / downlink configuration of the B area that is adjacent to the A area to the second type, And the uplink / downlink configuration of the adjacent C region is set to the third type so that interference between the regions can be minimized. Here, the uplink / downlink configuration of the second type may be set to a value included in the range between the uplink / downlink configuration of the first type and the uplink / downlink configuration of the third type. For example, the cell control apparatus 200 sets the uplink / downlink configuration of the A region to a 3: 1 ratio, sets the uplink / downlink configuration of the B region to a 2: 1 ratio, The downlink configuration can be set at a 1: 1 ratio.

3B, the cell control device 200 can divide the B region into the B1 region and the B2 region, and each of the B1 region and the B2 region has a different ratio of the uplink / downlink configuration Lt; / RTI >

4 is a flowchart illustrating an operation method of a cell control apparatus for minimizing interference between cells according to the present embodiment.

The cell control apparatus 200 collects radio resource information such as location information, configuration information, and beam information from each base station (S410). Here, the location information may include information on the location where the base station is installed, and may include information on latitude, longitude, altitude, etc., and the configuration information may include shape information of the base station, effective information radiated power (ERP) And Equivalent Isotropic Radiated Power (EIRP) information. Also, the beam information may include information such as a direction angle of the antenna, a beam width, an ANT gain, a beam pattern, and the like.

The cell control apparatus 200 generates a coverage map for each local station based on the radio resource information collected from each base station (S420), and measures the interference between the local stations using the coverage map (S430). Here, the cell control device 200 measures the degree of interference between cells with respect to an area where cell coverage overlaps.

The cell control apparatus 200 selects a target station to change the uplink / downlink configuration according to the measurement result of step S420 (S432). The cell control apparatus 200 generates a local list by deriving the stations whose inter-cell interference is equal to or greater than a predetermined interference threshold, and selects a target station to change the uplink / downlink configuration among the local list.

The cell control apparatus 200 changes the uplink / downlink configuration of the target station and confirms whether interference occurs between the target station and the surrounding stations based on the target station whose uplink / downlink configuration has been changed (S440). Herein, it is described that the cell control apparatus 200 operates on the basis of a target site whose uplink / downlink configuration has been changed. However, the present invention is not limited to this, and assuming that the uplink / downlink configuration of the target station is changed, It is also possible to extract the surrounding localities that are expected to be.

As a result of the checking in step S440, if there is no interference above a predetermined interference threshold between the target local station and the surrounding station (S442), the cell control device 200 maintains the changed uplink / downlink configuration of the target station in a changed state S444).

On the other hand, if it is determined in step S440 that interference occurs between the target local station and surrounding stations beyond a predetermined interference threshold (S442), the cell control device 200 extracts the neighboring stations where interference occurs (S446). Here, the neighboring local station in which the interference occurs may include a plurality of stations, and may include a plurality of cells or a base station.

The cell control apparatus 200 derives the layer setting information for changing the uplink / downlink configuration of the neighboring station according to the change of the uplink / downlink configuration of the target station (S450). Here, the layer setting information may include the number of layers between the target local region and the surrounding local region.

The cell control apparatus 200 calculates uplink / downlink configuration values for each layer based on the layer setting information, and applies the uplink / downlink configuration setting values to local areas corresponding to the respective layers (S460). Here, the local region corresponding to each layer may be a local region among the surrounding local regions.

The cell control apparatus 200 may repeat steps S430 to S470 if it is determined whether interference has occurred further among the target local or peripheral stations (S470).

4, it is described that steps S410 to S470 are sequentially executed. However, this is merely an example of the technical idea of the present embodiment, and it should be understood by those skilled in the art that the present invention is not limited to this embodiment It will be understood that various changes and modifications may be made to the invention without departing from the essential characteristics thereof, such as by changing the order described in FIG. 4 or by executing one or more of steps S410 through S470 in parallel, But is not limited thereto.

As described above, the operation of the cell control device 200 according to the present embodiment described in Fig. 4 can be implemented by a program and recorded in a computer-readable recording medium. A program for implementing the operation of the cell control device 200 according to the present embodiment is recorded, and the computer-readable recording medium includes all kinds of recording devices for storing data that can be read by the computer system. Examples of such computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, etc., and also implemented in the form of a carrier wave (e.g., transmission over the Internet) . The computer readable recording medium may also be distributed over a networked computer system so that computer readable code in a distributed manner may be stored and executed. In addition, functional programs, codes, and code segments for implementing the present embodiment can be easily inferred by programmers in the technical field to which the present embodiment belongs.

The foregoing description is merely illustrative of the technical idea of the present embodiment, and various modifications and changes may be made to those skilled in the art without departing from the essential characteristics of the embodiments. Therefore, the present embodiments are to be construed as illustrative rather than restrictive, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

As described above, the present embodiment is applied to the field of wireless communication, and it is possible to set different uplink / downlink configurations for each of a plurality of stations, maximize traffic acceptance efficiency of the network, satisfy various service requirements It is a useful invention that has the effect of utilizing the network to do.

110, 111, 112, 113, 114, 115, 116:
120, 121, 122, 123, 124, 125, 126:
200: cell control device 210: information collecting part
220: Coverage map generator 230:
240: interference control unit 242: interference measurement unit
244: Layer setting section 246: Link configuration setting section

Claims (9)

An apparatus for minimizing interference between a plurality of base stations using a TDD (Time Division Duplex) scheme,
A local extracting unit for extracting a target region in which interference occurs using radio resource information collected from each of the plurality of base stations; And
(UL) configuration of the target local station, and for minimizing interference between the target local station and neighboring local stations based on the target local station, an uplink / downlink configuration An interference control unit
And a cell control unit for controlling the cell control unit. The method according to claim 1,
Wherein the interference control unit comprises:
An interference measuring unit for measuring interference between the target local station and surrounding stations and for extracting neighboring stations where interference occurs;
A layer setting unit for deriving layer setting information for changing an uplink / downlink configuration of the neighboring local station based on a target region in which the uplink / downlink configuration is changed; And
A link configuration setting unit for applying a set value of an uplink / downlink configuration to at least one layer generated based on the layer setup information,
And a cell control unit for controlling the cell control unit. 3. The method of claim 2,
Wherein the interference measuring unit comprises:
And extracts the neighboring localities in which the interference occurs if interference occurs between the target local terminal and the neighboring local terminal with a predetermined upper or lower downlink configuration with a predetermined interference threshold or more. 3. The method of claim 2,
The layer setting unit,
The method comprising: confirming the uplink / downlink configuration of the target station and the uplink / downlink configuration of the neighboring stations, generating at least one layer based on the result of the check, and deriving the number of layers as the layer setting information . 5. The method of claim 4,
The layer setting unit,
Wherein the uplink / downlink configuration setting value is calculated based on the uplink / downlink configuration value of the target station and the uplink / downlink configuration value of the neighboring stations, Is calculated within a range between the set values. 3. The method of claim 2,
The link configuration setting unit
Wherein the set value of the uplink / downlink configuration calculated in the at least one layer including a part of the neighboring local stations is applied according to the layer setting information. 3. The method of claim 2,
The cell control device includes:
When the adjustment of the uplink / downlink configuration for the target local station and the neighboring local station is completed, a neighboring station where interference occurs based on the local station included in the at least one layer is newly detected and the uplink / downlink configuration is adjusted And repeats the operation. A method for minimizing interference between a plurality of base stations using a TDD (Time Division Duplex) scheme,
A local extracting step of extracting a target region where interference occurs using radio resource information collected from each of the plurality of base stations; And
(UL) configuration of the target local station, and for minimizing interference between the target local station and neighboring local stations based on the target local station, an uplink / downlink configuration Interference control process to adjust setting value
Based on the link information. 9. The method of claim 8,
The interference control process includes:
An interference measurement process of measuring interference between the target local and peripheral stations and extracting surrounding localities where interference occurs;
A layer setup process for deriving layer setup information for changing the uplink / downlink configuration of the neighboring local stations based on the target local areas for which the uplink / downlink configuration is changed; And
And a link configuration setting process of applying a setup value of the uplink / downlink configuration to at least one layer generated based on the layer setup information
Based on the link information.

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