KR102103875B1 - Method and Apparatus for Configuration of Link Based on Time Division Duplex for Controlling Inter-Cell Interference - Google Patents

Abstract

Disclosed is a TDD-based link configuration method for controlling inter-cell interference and an apparatus therefor.
TDD-based link configuration method for measuring inter-local interference using a TDD scheme, setting a layer for minimizing inter-local interference, and controlling inter-cell interference for adjusting up / downlink configuration for each layer, and It is about the device for.

Description

TDD-based link configuration method for controlling inter-cell interference and a device therefor {Method and Apparatus for Configuration of Link Based on Time Division Duplex for Controlling Inter-Cell Interference}

The present 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 for this embodiment, and do not constitute a prior art.

The mobile communication system uses duplex technology to service downlink (DL) and uplink (UL). The duplex technology can be roughly divided into a frequency division duplex (FDD) method and a time division duplex (TDD) method.

In the case of the FDD method, a frequency band for DL and a frequency band for UL are fixedly allocated and used. As the use of the frequency band cannot be changed, it is difficult to perform a special response even if DL traffic increases.

On the other hand, in the case of the TDD method, the same frequency band is allocated to DL or UL according to time, and DL and UL can be allocated and used in units of subframes within one frame.

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

In the TDD method, although the settings of the uplink / downlink configuration (DL, UL Configuration) can be set differently according to the required service environment for each unit such as a base station (Cell), a cluster (Cluster), in an actual network environment, interference (Interference) It is difficult to use due to the influence.

For example, in the TDD scheme, when different configurations of the uplink / downlink configuration are used for each predetermined unit, the base station B, which is a neighbor base station, is used while the uplink of the A base station 110 is used because the same frequency is used. If the downlink is used, the downlink signal of the B base station 111 is received by the A base station 110 to act as 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 base stations included in a predetermined area are equally set to prevent mutual interference. However, the TDD scheme that matches the uplink / downlink configuration equally serves as a factor that decreases the traffic acceptance efficiency of the network.

Accordingly, there is a need for a method capable of differently applying the configuration of the uplink / downlink configuration while minimizing interference between cells (regions and localities) in the TDD scheme.

This embodiment is a TDD-based link for controlling inter-cell interference, which measures interference between stations using a TDD scheme, sets a layer for minimizing interference between stations, and adjusts an uplink / downlink configuration for each layer. The main purpose is to provide a method of construction and an apparatus therefor.

According to an aspect of the present embodiment, in an apparatus for minimizing interference between a plurality of base stations using a time division duplex (TDD) method, a target local area where interference occurs using radio resource information collected from each of the plurality of base stations Local extraction unit for extracting; And uplink / downlink configuration of some of the neighboring localities in order to change the UL / UL configuration (DL) of the target locality and minimize interference between the target locality and the neighboring localities based on the target locality. It provides a cell control device comprising an interference control unit for adjusting the set value of.

In addition, according to another aspect of the present embodiment, in a method of minimizing interference between a plurality of base stations using a time division duplex (TDD) method by a cell control device, interference is performed using radio resource information collected from each of the plurality of base stations. A local extraction process for extracting the target area where this occurs; And uplink / downlink configuration of some of the neighboring localities in order to change the UL / UL configuration (DL) of the target locality and minimize interference between the target locality and the neighboring localities based on the target locality. It provides a TDD-based link configuration method characterized in that it comprises an interference control process for adjusting the set value of.

As described above, according to the present embodiment, the cell control device has an effect of setting different up / down link configurations in each of a plurality of stations in order to minimize interference between the stations.

In addition, according to the present embodiment, as different up / down link configurations can be set for each of a plurality of locals, it is possible to maximize the traffic acceptance efficiency of the network and 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.
3A and 3B are exemplary views illustrating an operation for setting a frame and setting a layer for minimizing interference between cells according to the present embodiment.
4 is a flowchart illustrating a method of operating a cell control device for minimizing interference between cells according to the present embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. '… As described herein. Terms such as "unit" and "module" mean 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.

This embodiment can be applied to a mobile communication system (Evolved Packet System or Long Term Evolution System) operating based on the 3GPP standard. For example, this embodiment is based on LTE (Long Term Evolution), LTE-Advanced system, LTE-Advanced Pro system, as well as next-generation wireless communication system (eg, 5th-generation system) or other communication system based next-generation mobile / wireless communication. It can also be applied to the system.

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

The communication system 100 according to the present embodiment includes a plurality of base stations 110, 111, 112, 113, 114, 115, 116, a plurality of cells 120, 121, 122, 123, 124, 125, 126, and a plurality of It includes a terminal (not shown), and the like, the communication system 100 represents a system in which a plurality of cells in which overlapping regions exist.

As illustrated in FIG. 1, when a distance between cells is close in a network environment in which a plurality of cells coexist, interference between adjacent cells may occur, and the closer the distance between cells, the greater the interference. The plurality of cells illustrated in FIG. 1 may be macro cells, but may be small cells in the form of picocells, femtocells, etc. to increase transmission capacity per unit area through frequency reuse, and macros. It is also possible to mix cells and small cells.

The communication system 100 according to this embodiment is premised on a network environment in which a plurality of cells are densely or coexisting, and each cell adopts and uses a time division duplex (TDD) method. Here, the communication system 100 may be in the form of a coexistence network in which a TDD scheme and a FDD (Frequency Division Duplex) scheme coexist if a TDD scheme can be used. In the case of the TDD method, the same frequency band is allocated and used in a downlink (DL) or uplink (UL) according to time, and can be used by allocating downlink and uplink in subframe units within one frame. have.

The TDD method can increase the traffic acceptance efficiency of the network by differently setting up / downlink configuration (DL, UL Configuration) according to a service environment required for each unit such as a base station (Cell) and a cluster (Cluster). In a real network environment, it is difficult to use due to interference.

Referring to FIG. 1, when each of a plurality of base stations 110, 111, 112, 113, 114, 115, and 116 installed in the communication system 100 uses different up / down link configuration settings, an uplink signal and Since a downlink signal is mixed, interference occurs between the first base station 110 and the neighboring base stations 111, 113, 115, and 116, for example.

In this embodiment, various requirements of related service functions may be reflected as technology development of the 4G system and the 5G system can be reflected, and eMBB (enhanced Mobile BroadBand), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive machine) Type Communication), and proposes a method to efficiently set up / downlink configuration in terms of network configuration support that can accommodate various services.

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 collection unit 210, a coverage map generation unit 220, a local extraction unit 230, and an interference control unit 240. The cell control device 200 shown in FIG. 2 is according to an embodiment, and not all blocks shown in FIG. 2 are essential components, and in another embodiment, some blocks included in the cell control device 200 are added. , Can be changed or deleted.

The cell controller 200 measures interference of a local station (cell, base station, cluster, etc.) using a TDD scheme, and controls layer setting and uplink / downlink configuration settings to minimize interference between the local stations. The cell control device 200 may be a wireless network design and analysis system interworking with LTE, LTE-Advanced system, LTE-Advanced pro system, 5th generation system, etc., but is not limited thereto, and is provided in a macro cell or small cell base station Or it can be implemented as an external server.

The information collection 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 is information about the location where the base station is installed, and may include information on latitude, longitude, altitude, etc., and the configuration information includes shape information, output information (ERP: Effective Radiated Power), and equivalent isotropic radiation of the base station. Equivalent Isotropic Radiated Power (EIRP) information. In addition, the beam information may include information such as an antenna's directivity angle, beam width, gain (ANT gain), and beam pattern.

The information collecting unit 210 may receive radio resource information transmitted from each base station at a predetermined period or at a predetermined time, but is not limited thereto, and the radio resource information is a response signal according to the request of the cell control device 200. Can be obtained.

The coverage map generation unit 220 generates a coverage map for each district based on radio resource information collected from the base station.

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

The coverage map generation unit 220 generates a coverage map to determine interference between the stations, and the generated coverage map may be kept up to date using the radio resource information periodically collected, that is, continuously updated.

The local extraction unit 230 measures interference between the locals using the coverage map, and selects target locals to change the UL / DL configuration due to the interference. Specifically, the local extracting unit 230 generates a local list by deriving locals measured as interferences between cells based on a coverage map that are greater than or equal to a preset interference threshold, and constructs an uplink / downlink configuration from a local list (DL: UL Configuration) ) Select the target area to be changed. Here, the local extraction unit 230 is preferably selected as the target locality of the locality list having the highest interference measurement among the local lists, but is not limited thereto.

The local extracting unit 230 measures interference between localities in which cell coverage overlaps, and determines whether to change the uplink / downlink configuration of the target locality based on a preset interference threshold. That is, the local extraction unit 230 compares the measured interference measurement value with a preset interference threshold and selects a local area that exceeds the interference threshold as a target local area for changing the uplink / downlink configuration. Here, the local extraction unit 230 may measure interference between at least one of uplink interference and downlink interference in measuring interference between local stations. For example, the local extraction unit 230 may measure downlink interference between the stations. Here, the measurement of downlink interference may use a pilot signal having a unique pattern for each cell, and when one cell among the plurality of cells transmits the pilot signal to the remaining cells, the cell transmitting the pilot signal from the remaining cells It may be a method of measuring the interference of, and various other measurement methods may be applied.

The interference control unit 240 changes the setting of the uplink / downlink configuration of the target station, and adjusts the uplink / downlink configuration of the neighboring stations to minimize interference with the neighboring station 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 control unit 240 performs an operation for minimizing inter-local interference after changing the up / down link configuration of the extracted target local. Here, the uplink / downlink configuration change of the target locality may be performed by the link configuration setting unit 246, but is not limited thereto, and assuming that the uplink / downlink configuration of the target locality is changed, the interference between the local areas is minimized. It may also perform an operation for.

The interference measurement unit 242 checks whether interference occurs between the target station and the neighboring stations based on the target station where the uplink / downlink configuration is changed, and extracts neighboring stations where interference occurs.

The interference measurement unit 242 compares the uplink / downlink configuration of the target local area with the uplink / downlink configuration of the surrounding local area, and detects the surrounding local area in which interference occurs when interference exceeds a predetermined interference threshold between the target local area and the surrounding local area. To extract. Here, the surrounding local area where the interference occurs may include a plurality of local areas, and may include a plurality of cells or a base station.

On the other hand, if there is no surrounding local area where interference occurs, the interference measurement unit 242 maintains the setting of the target local area where the uplink / downlink configuration is changed and the surrounding local area having the existing uplink / downlink configuration.

The hierarchical setting unit 244 derives hierarchical setting information for changing the uplink / downlink configuration of the neighboring topic according to the uplink / downlink configuration change of the target locality. Here, the layer setting information may include the number of layers between the target station and the neighboring stations, a link configuration setting value of each layer, and the like.

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

The uplink / downlink configuration may be a ratio of the uplink / downlink separately set for each of a plurality of localities, but may be one of the preset uplink / downlink configurations (conf.0 to conf.6) as described in [Table 1]. Can be. The uplink / downlink configuration may be applied based on 3GPP LTE as shown in [Table 1], but is not limited thereto, and a configuration configuration based on next generation wireless communication technology such as 3GPP 5G NR (New Radio) may also 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' is a downlink subframe, 'U' is an uplink subframe, and 'S' is a switching point (DwPTS (Downlink Pilot Time Slot) + GP (Guard Period) + UpPTS (Uplink Pliot Time Slot) )).

The link configuration setting unit 246 changes the up / down link configuration of the target local area. The link configuration setting unit 246 calculates a set value for changing the uplink / downlink configuration of the target 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 the setting values of the uplink / downlink configuration for the generated layer to minimize interference between the target local and neighboring locals. The link configuration setting unit 246 of the uplink / downlink configuration calculated by the layer setting unit 244 in at least one base station included in a layer including some of the neighboring localities according to the layer setting information based on the target locality Send the set value.

After changing the uplink / downlink configuration for the layer, the link configuration setting unit 246 additionally transmits additional interference measurement signals for measuring interference to the interference measurement unit 242 to additionally generate local areas where interference may occur. Try to detect. Here, the additionally detected locality may be localized according to a result of measuring the interference of surrounding localities based on the layer in which the uplink / downlink configuration is changed.

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

Referring to (a) of FIG. 3A, the cell control device 200 sets up / downlink configuration (DL: UL configuration) differently from the region A (or the base station A) and the region other than the region A. For example, the cell controller 200 sets the uplink / downlink configuration of the area A (base station A) at a ratio of 3: 1, and the rest of the area except for the area A is the existing uplink / downlink configuration 1: Maintain 1 ratio. In this case, as shown in (b) of FIG. 3A, interference occurs in a time 1/4 region between regions A and regions other than region A.

In a real network environment, when two base stations are adjacent to each other and the interference signal is received, interference occurs due to the uplink / downlink configuration, so that different uplink / downlink configurations cannot be established between adjacent base stations.

The cell control apparatus 200 according to the present embodiment extracts a neighboring base station at a location where interference occurs based on a predetermined base station (A base station). Here, the cell control device 200 may extract a base station target that can interfere with neighboring base stations using configuration information for each base station, beam information, and the like. Here, the configuration information may include shape information, output information, equivalent isotropic radiation power (EIRP) information of the base station, and beam information, such as an antenna's directivity angle, beam width, gain (ANT gain), beam pattern, etc. Information may be included.

A neighboring base station at a location where interference occurs based on a predetermined base station (A base station) may be a base station located in area B in FIG. As described above, if the base stations in region B, which are determined to cause 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, but the base stations / base stations in region B When the downlink configuration is adjusted to a 2: 1 ratio, the region where interference occurs is reduced because about 16.5% of the region is an interference region. That is, as the up / downlink configuration of region B is changed in FIG. 3B (b), region A and region C except region B use the existing up / downlink configuration 1: 1 ratio while maintaining region A and region A. To reduce interference.

The operation of the cell control apparatus 200 according to the present embodiment is summarized as follows with reference to FIG. 3B (a). In a network environment based on a TDD scheme in which coverages of a plurality of base stations are overlapped, the cell control apparatus 200 according to the present embodiment sets up / downlink configuration of the A region selected as the interference-affected region as the first type, Interference can be minimized by setting up / downlink configuration of the rest of the regions except the A region in a multi-level hierarchical structure. For example, the cell control device 200 sets the upper / downlink configuration of the A area to the first type, sets the upper / downlink configuration of the B area adjacent to the A area to the second type, and the B area and By setting the uplink / downlink configuration of adjacent C regions to the third type, interference between regions can be minimized. Here, the uplink / downlink configuration of the second type may be set to a value included in a range between the uplink / downlink configuration of the first type and the uplink / downlink configuration of the third type. For example, the cell control device 200 sets the upper / downlink configuration of the A region to a 3: 1 ratio, and then sets the upper / downlink configuration of the B region to a 2: 1 ratio, and upper / lower C regions. The downlink configuration may be set at a 1: 1 ratio.

In addition, as shown in (b) of FIG. 3B, the cell control device 200 may divide the B region into the B1 region and the B2 region, and each of the B1 region and the B2 region has different ratios of up / down links. Can be set to

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

The cell control device 200 collects radio resource information such as location information, configuration information, and beam information from each base station (S410). Here, the location information is information about the location where the base station is installed, and may include information on latitude, longitude, altitude, etc., and the configuration information includes shape information, output information (ERP: Effective Radiated Power), and equivalent isotropic radiation of the base station. Equivalent Isotropic Radiated Power (EIRP) information. In addition, the beam information may include information such as an antenna's directivity angle, beam width, gain (ANT gain), and beam pattern.

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

The cell control device 200 selects a target local to change the up / down link configuration according to the measurement result of step S420 (S432). The cell control apparatus 200 generates a local list by deriving local stations whose interference between cells is equal to or greater than a preset interference threshold, and selects a target local to change the uplink / downlink configuration from the local list.

The cell control device 200 changes the uplink / downlink configuration of the target station, and checks whether interference between the target station and the neighboring stations occurs based on the target station where the uplink / downlink configuration is changed (S440). Here, the cell control device 200 is described as operating based on the target locality where the uplink / downlink configuration is changed, but is not limited thereto, and assuming that the uplink / downlink configuration of the target locality is changed, interference occurs. It is also possible to extract surrounding areas that are expected to be.

As a result of the check in step S440, when there is no interference greater than a preset interference threshold between the target station and the neighboring stations (S442), the cell controller 200 maintains the changed uplink / downlink configuration of the target station in a changed state ( S444).

On the other hand, as a result of the check in step S440, when the interference occurs above the predetermined interference threshold between the target local and the surrounding local (S442), the cell control device 200 extracts the surrounding local where the interference occurs (S446). Here, the surrounding local area where the interference occurs may include a plurality of local areas, and may include a plurality of cells or a base station.

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

The cell control device 200 calculates the uplink / downlink configuration settings for each layer based on the layer configuration information, and applies the uplink / downlink configuration settings to the local area corresponding to each layer (S460). Here, the local area corresponding to each layer may be a partial local area.

The cell control apparatus 200 may repeatedly perform steps S430 to S470 when it is determined whether additional interference occurs among the target local or the local local (S470).

Although FIG. 4 describes that steps S410 to S470 are sequentially executed, this is merely illustrative of the technical idea of the present embodiment, and those skilled in the art to which this embodiment belongs belongs to this embodiment. Since the order described in FIG. 4 may be changed without departing from the essential characteristics, or one or more steps of steps S410 to S470 may be executed in parallel, various modifications and variations may be applied, so FIG. 4 is a time series sequence. It is not limited.

As described above, the operation of the cell control device 200 according to the present embodiment described in FIG. 4 may be implemented as a program and recorded in a computer-readable recording medium. The 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 types of recording devices in which data that can be read by a computer system is stored. 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 (for example, transmission via the Internet). It also includes. In addition, the computer readable recording medium may be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 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 this embodiment belongs.

The above description is merely illustrative of the technical idea of the present embodiment, and those skilled in the art to which this embodiment belongs may be capable of various modifications and variations without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical spirit of the present embodiment, but to explain, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present embodiment.

As described above, this embodiment is applied to the field of wireless communication, and it is possible to set up / downlink configurations different for each of a plurality of locales, maximize traffic acceptance efficiency of a network, and satisfy various service requirements It is a useful invention to generate an effect that can utilize the network.

110, 111, 112, 113, 114, 115, 116: multiple base stations
120, 121, 122, 123, 124, 125, 126: multiple cells
200: cell control unit 210: information collection unit
220: coverage map generation unit 230: local extraction unit
240: interference control unit 242: interference measurement unit
244: layer setting unit 246: link configuration setting unit

Claims (9)

In the apparatus for minimizing interference between a plurality of base stations using a time division duplex (TDD) method,
A local extraction unit for extracting a target local area where interference occurs using radio resource information collected from each of the plurality of base stations;
An interference measurement unit for measuring interference between the target local area and the surrounding local area, and extracting the surrounding local area where interference occurs;
A layer setting unit that checks the uplink / downlink configuration of the target station and the uplink / downlink configuration of the neighboring stations, generates at least one layer based on the verification result, and derives the number of layers as layer setting information ; And
Link configuration setting unit that applies the setting value of the uplink / downlink configuration to the at least one layer based on the layer setting information
Cell control device characterized in that it comprises a. delete According to claim 1,
The interference measurement unit,
A cell control device for extracting the surrounding local area where interference occurs when an interference greater than a preset interference threshold occurs between the target local area where the uplink / downlink configuration is changed and the peripheral local area. delete According to claim 1,
The layer setting unit,
The uplink / downlink configuration settings for applying to each of the at least one layer are calculated, and the uplink / downlink configuration settings include the uplink / downlink configuration settings of the target station and the uplink / downlink configuration of the neighboring stations. A cell control device characterized in that it is calculated within a range between set values. According to claim 1,
The link configuration setting unit,
And applying the set value of the uplink / downlink configuration calculated to the at least one layer including some of the surrounding localities according to the layer configuration information. According to claim 1,
The cell control device,
When the adjustment of the uplink / downlink configuration for the target locality and the neighboring localization is completed, the neighboring local area having interference based on the locality included in the at least one layer is newly detected and the uplink / downlink configuration is adjusted. Cell control device characterized in that the operation is repeated. In a method for configuring a cell division apparatus based on a time division duplex (TDD) link for controlling inter-cell interference,
Extracting a target local area where interference occurs using radio resource information collected from each of a plurality of base stations; And
Measuring the interference between the target local area and the surrounding local area, and extracting the surrounding local area where the interference occurs;
Checking the uplink / downlink configuration of the target station and the uplink / downlink configuration of the surrounding stations, generating at least one layer based on the result of the verification, and deriving the number of layers as layer configuration information; And
Process of applying setting values of the uplink / downlink configuration to the at least one layer based on the layer setting information
TDD-based link configuration method comprising a.
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