KR102029929B1 - Method and apparatus for performing resource management for inter-cell interference control in a mobile communications network - Google Patents

Abstract

The present invention provides a resource management method in a small cell. According to the present invention, the resource management method comprises the steps of: receiving the number (N) of resource block (RB) regions; and determining to use either a first RB allocation pattern or a third RB allocation pattern, which corresponds to a physical cell identifier (PCI) subgroup of the small cell if N is 3. The PCI subgroup is determined according to a PCI modulo 3 (PCI mod 3) that the small cell is currently using.

Description

Method and apparatus for performing resource management for inter-cell interference control in a mobile communication network

The present invention relates to a technique for indirect cell-to-cell control between small cells in a mobile communication network, and more particularly, to a technique for performing resource management for controlling interference between small cells in a mobile communication network.

In recent years, a radio access network includes a small cell such as a micro cell, a pico cell, a femto cell, and a relatively large macro cell. It is evolving in interlocking form. A small cell is a low-power wireless access node, which has a relatively narrower service area than a normal cell, and is similar to a DSL modem, and can be connected to a wired IP network in a home to use wired and wireless communication freely with a terminal such as a mobile phone. Small cells reduce the size of cells according to Cooper's Law in order to solve the problem that the more users per base station, the less efficient and the poor quality and shadowed areas in the cell boundary area and building. It has been proposed for the purpose of increasing the density of traffic by placing the terminal close to the base station. Using a small cell has the following advantages: First, power consumption of the terminal is reduced. When the UE and the base station are located close to each other, it is more efficient in power consumption because it can transmit and receive signals with very little power. Second, the benefits of multiple-input and multiple output (MIMO) are maximized. According to the recent trend of the use of mobile traffic, most of the generated traffic is generated indoors, so it is expected that many small cells will be installed mainly indoors in the future. In this indoor environment, multiple passes of the radio signal at different angles are possible, which maximizes the advantages of MIMO, enabling efficient use of the spectrum. Third, there is an advantage that the installation cost and maintenance cost is less than the existing base station.

The mobile communication network composed of such small cells has a greater effect of interference on the terminal due to the higher cell installation density than that of the conventional macro cells. In particular, a terminal located in a cell edge (CE) region, which is a relatively large boundary area from a serving small cell, is greatly affected by interference due to signals from neighboring small cells. Therefore, the need to increase the throughput of the terminal located in the CE area has emerged, and for this purpose, the "resource management" technique, which is one of the functions of the small cell self-organizing network (SON) module, has been utilized. . RM is sometimes referred to as "InterCell Interference Coordination" (ICIC) or "Soft Frequency Fractional Reuse" (SFR), which is a physical downlink shared channel (PDSCH) power that is relatively high for the band allocated to the CE region among the bands available for small cells. By allocating a low PDSCH power in a band allocated to a cell center (Cell) area, which is a relatively close area from the serving small cell, improves the throughput performance of the UE located in the CE area. The RM also prevents overlapping bands allocated to the CE region and bands allocated to the CC region in the relationship between adjacent small cells, thereby greatly increasing the throughput of the UE located in the CE region and the throughput of the UE located in the CC region almost intact. To maintain it. However, in order to implement the RM function, it is necessary to determine which band is to be allocated as a band for the CE region and which band is to be allocated as a band for the CC region in the band where each small cell is available.

Several existing techniques are known for dividing the band available for each small cell into a band for the CE area and a band for the CC area. As a first method, an operator directly uses a management server to manage each band. A technique for specifying is known. In the second technique, the small cell determines the band for the CE region and the band for the CC region according to the surrounding environment of the small cell. The first technique may be effective if the operator does cell planning, but the band and CE band for each of the small cells installed every time a new cell is installed or the surrounding environment changes. The operator must decide a new band for the CC area, but it is difficult to actually do so. Furthermore, due to the nature of small cell networks with high cell installation density, it is not easy to predict the surrounding environment, and thus, it is practically difficult to newly determine each band for all installed small cells. In the second technique, small cells need to exchange information about which band is used as a band for the CE region and which band is used as a band for the CC region. Indication Message is necessary. As the number of installed small cells increases, the number of Load Indication Messages required also increases, which may lead to an increase in network load.

An object of the present invention is to enable the small cell itself to determine which part of the total available band of the small cell to use as the band for the CE region and which part of the band to use as the band for the CC region without additional network load, It is to provide a resource management method and apparatus for inter-cell interference control.

Problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In one aspect, a method of resource management in a small cell is provided. The method includes receiving a number (N) of RB regions (Resource Block Regions), and when N is 3, a physical cell identifier (PCI) subgroup of the small cell as an RB allocation pattern for the small cell. And determining to use an RB allocation pattern of any one of the first to third RB allocation patterns, corresponding to the RB allocation pattern. The PCI subgroup may be determined according to a PCI value 3 (PCI mod 3) of the PCI module that the small cell is currently using.

The determining may include determining that the first RB allocation pattern is used as an RB allocation pattern for the small cell when the PCI subgroup of the small cell is 1, and the PCI subgroup of the small cell is determined. If the group is 2, it is determined that the second RB allocation pattern is used as the RB allocation pattern for the small cell. If the PCI subgroup of the small cell is 3, the third RB allocation pattern for the small cell is determined. Determining to use the RB allocation pattern.

In example embodiments, the first RB allocation pattern is a pattern in which a Cell Edge Resource Block Region (CER) region, a first Cell Center Resource Block Region (CCR) region, and a second CCR region are concatenated, and the second RB allocation pattern May be a pattern in which the first CCR region, the CER region, and the second CCR region are concatenated, and the third RB allocation pattern may be a pattern in which the first CCR region, the second CCR region, and the CER region are concatenated.

In one embodiment, the first RB allocation pattern is a pattern in which a CER region, a first CCR region and a second CCR region are concatenated, and the second RB allocation pattern is a first CCR region, a second CCR region and a CER region. The third RB allocation pattern may be a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated.

In one embodiment, the first RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated, and the second RB allocation pattern is a CER region, a first CCR region, and a second CCR region. The third RB allocation pattern may be a concatenated pattern, and the first CCR region, the second CCR region, and the CER region may be concatenated.

In one embodiment, the first RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated, and the second RB allocation pattern is a first CCR region, a second CCR region, and a CER region. The third RB allocation pattern may be a concatenated pattern, and the CER region, the first CCR region, and the second CCR region may be concatenated.

In one embodiment, the first RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated, and the second RB allocation pattern is a first CCR region, a CER region, and a second CCR region. The third RB allocation pattern may be a concatenated pattern, and the CER region, the first CCR region, and the second CCR region may be concatenated.

In one embodiment, the first RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated, and the second RB allocation pattern is a CER region, a first CCR region, and a second CCR region. The third RB allocation pattern may be a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated.

In one embodiment, the determining may be performed when the small cell is booted up, when the PCI of the small cell is changed, or the neighbor relation table (NRT) inside the small cell is updated. Can be.

In one embodiment, the determining may be performed when a PCI collision or a Cell Reference Symbol (CRS) collision does not occur.

In another aspect, a method of resource management in a small cell is provided. The method may include checking whether the PCI subgroup of the small cell is 3, and if it is determined that the PCI subgroup of the small cell is not 3, the PCI subgroup of the small cell as an RB allocation pattern for the small cell. Determining that one of the first RB allocation pattern and the second RB allocation pattern corresponds to the RB allocation pattern, and when the PCI subgroup of the small cell is determined to be 3, the periphery of the small cell; The method may include determining an RB allocation pattern for the small cell based on information representing an environment. The PCI subgroup may be determined according to a PCI value 3 (PCI mod 3) of the PCI module that the small cell is currently using.

In an embodiment, determining to use one of the first RB allocation pattern and the second RB allocation pattern corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell. Is determined to use the first RB allocation pattern as the RB allocation pattern for the small cell when the PCI subgroup of the small cell is 1; and if the PCI subgroup of the small cell is 2, And determining to use the second RB allocation pattern as an RB allocation pattern for the RB allocation pattern.

In an embodiment, the first RB allocation pattern may be a pattern in which a CER region and a CCR region are concatenated, and the second RB allocation pattern may be a pattern in which the CCR region and a CER region are concatenated.

In an embodiment, the first RB allocation pattern may be a pattern in which the CCR region and the CER region are concatenated, and the second RB allocation pattern may be a pattern in which the CER region and the CCR region are concatenated.

In one embodiment, checking whether the PCI subgroup of the small cell is 3, the first RB allocation pattern and the second RB allocation, corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell. Determining to use one of the RB allocation pattern of the pattern and determining the RB allocation pattern for the small cell based on the information indicating the surrounding environment of the small cell, the small cell is in the boot-up state This may be performed when the PCI of the small cell is changed or the NRT inside the small cell is updated.

In one embodiment, checking whether the PCI subgroup of the small cell is 3, the first RB allocation pattern and the second RB allocation, corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell. Determining to use the RB allocation pattern of any one of the patterns and determining the RB allocation pattern for the small cell based on the information representing the surrounding environment of the small cell, the PCI collision or CRS collision does not occur Case may be performed.

In an embodiment, the determining of the RB allocation pattern for the small cell based on the information representing the surrounding environment of the small cell may serve as the highest interference source for the small cell, and thus may determine the NRT of the small cell. Checking whether the recorded PCI subgroup of the adjacent small cell is 1 or 2, and if it is determined that the PCI subgroup of the adjacent small cell is 1, a reference signal received power (RSRP) of the adjacent small cell And checking whether an adjacent small cell having a RSRP higher than a predetermined threshold difference and a PCI subgroup of 2 is recorded in the NRT of the small cell, and a difference between the RSRP of the adjacent small cell and the predetermined threshold value. If it is determined that an adjacent small cell having a higher RSRP and a PCI subgroup of 2 is not recorded in the NRT of the small cell, the small As RB allocation patterns for the can include determining that the use of the claim 2 RB allocation patterns.

In an embodiment, the determining of the RB allocation pattern for the small cell based on the information representing the surrounding environment of the small cell may include determining that the PCI subgroup of the neighboring small cell is 2; Checking whether an adjacent small cell having a RSRP higher than the difference between the RSRP and the predetermined threshold of the PCI subgroup is 1 in the NRT of the small cell, and the RSRP of the adjacent small cell and the predetermined value If it is determined that an adjacent small cell having an RSRP higher than the determined threshold difference and a PCI subgroup of 1 is not recorded in the NRT of the small cell, the first RB allocation pattern is used as the RB allocation pattern for the small cell. The method may further include determining to.

In another aspect, an apparatus for resource management in a small cell is provided. The apparatus includes: a storage unit for storing information about PCI currently used by the small cell, and a first RB allocation pattern to a first sub-group corresponding to the PCI subgroup of the small cell as an RB allocation pattern for the small cell; And a processor configured to determine to use one of the three RB allocation patterns. The processor may be further configured to identify the PCI subgroup of the small cell according to the modulo 3 value (PCI mod 3) of the PCI stored in the storage.

In one embodiment, when the PCI subgroup of the small cell is 1, the processor determines to use the first RB allocation pattern as the RB allocation pattern for the small cell, and the PCI subgroup of the small cell is determined. If 2, it is determined that the second RB allocation pattern is used as the RB allocation pattern for the small cell. If the PCI subgroup of the small cell is 3, the third RB allocation is used as the RB allocation pattern for the small cell. It may be further configured to determine to use the pattern.

In example embodiments, the first RB allocation pattern is a pattern in which a Cell Edge Resource Block Region (CER) region, a first Cell Center Resource Block Region (CCR) region, and a second CCR region are concatenated, and the second RB allocation pattern May be a pattern in which the first CCR region, the CER region, and the second CCR region are concatenated, and the third RB allocation pattern may be a pattern in which the first CCR region, the second CCR region, and the CER region are concatenated.

In another aspect, an apparatus for resource management in a small cell is provided. The apparatus includes a storage unit for storing information about PCI currently used by the small cell, and the PCI subgroup of the small cell as an RB allocation pattern for the small cell when the PCI subgroup of the small cell is not three. Information indicating a surrounding environment of the small cell when the PCI subgroup of the small cell is 3, determined to use one of the first RB allocation pattern and the second RB allocation pattern corresponding to the group; And a processor configured to determine an RB allocation pattern for the small cell based on. The processor may be further configured to identify the PCI subgroup of the small cell according to the modulo 3 value (PCI mod 3) of the PCI stored in the storage.

In one embodiment, when the PCI subgroup of the small cell is 1, the processor determines to use the first RB allocation pattern as the RB allocation pattern for the small cell, and the PCI subgroup of the small cell is determined. 2 may be further configured to determine to use the second RB allocation pattern as the RB allocation pattern for the small cell.

In an embodiment, the first RB allocation pattern may be a pattern in which a CER region and a CCR region are concatenated, and the second RB allocation pattern may be a pattern in which the CCR region and a CER region are concatenated.

In one embodiment, the processor acts as the highest source of interference for the small cell such that the PCI subgroup of neighboring small cells recorded in the small cell's NRT is 1 and the RSRP of the neighboring small cell and a predetermined threshold If a neighbor small cell having a RSRP higher than the difference and PCI subgroup 2 is not recorded in the NRT of the small cell, determine to use the second RB allocation pattern as the RB allocation pattern for the small cell. It can be further configured.

In one embodiment, the processor acts as the highest interference source for the small cell such that the PCI subgroup of neighboring small cells recorded in the small cell NRT is 2 and the RSRP of the neighboring small cell and the predetermined If an adjacent small cell having a RSRP higher than the threshold difference and a PCI subgroup of 1 is not recorded in the NRT of the small cell, it is determined to use the first RB allocation pattern as the RB allocation pattern for the small cell. It can be further configured to.

According to embodiments of the present invention, the small cell itself does not use X2AP, which part of the total bands available for use by the small cell as the band for the CE region and which part is used as the band for the CC region. Decisions have the technical effect of significantly reducing the load on the network.

In addition, according to embodiments of the present invention, the operator by the small cell determines which part of the total bands available to the small cell to use as a band for the CE region and which part is to be used as a band for the CC region by the operator There is a technical effect of not having to specify each band directly.

1A and 1C are diagrams for conceptually explaining a resource management scheme performed in a small cell according to an embodiment of the present invention to control interference between small cells in a mobile communication network.
FIG. 1B is a diagram illustrating resource block (RB) allocation patterns allocated to a CE region and a CC region by dividing a band usable in the small cells of FIG. 1A according to an embodiment of the present invention.
FIG. 1D is a diagram illustrating RB allocation patterns allocated to one CE region and two CC regions by dividing an available RB region available in the small cells of FIG. 1C according to an embodiment of the present invention.
FIG. 1E is a diagram illustrating PCIs 91 to 99 and corresponding PCI subgroups according to an embodiment of the present invention.
2 is a block diagram of a small cell in which a resource management device for controlling interference between small cells in a mobile communication network according to an embodiment of the present invention and a block diagram of a terminal according to an embodiment of the present invention are shown. Drawing.
3A and 3B illustrate an embodiment of a flowchart for describing a resource management method for controlling interference between small cells in a mobile communication network.

Advantages and features of the present invention and a method of accomplishing the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and the present embodiments merely make the disclosure of the present invention complete and have ordinary skill in the art to which the present invention pertains. It is provided to fully inform the scope of the invention, and the invention is defined only by the scope of the claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, a component expressed in the singular should be understood as a concept including a plurality of components unless the context clearly indicates only the singular. In addition, in the specification of the present invention, terms such as 'comprise' or 'have' are merely intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist. The use of the term does not exclude the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof. In addition, in the embodiments described herein, 'module' or 'unit' may refer to a functional part performing at least one function or operation.

In addition, all terms used herein, including technical or scientific terms, unless otherwise defined, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and should be interpreted in ideal or excessively formal meanings unless expressly defined in the specification of the present invention. It doesn't work.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, in the following description, when there is a risk of unnecessarily obscuring the gist of the present invention, a detailed description of well-known functions and configurations will be omitted.

1A and 1C are diagrams for conceptually explaining a resource management scheme performed in a small cell according to an embodiment of the present invention to control interference between small cells in a mobile communication network.

1A and 1C, the small cells 110, 130, and 150 are low power wireless access base stations having small operating ranges of at least 10 m to several hundred meters. The small cells 110 and 130 may be classified into femtocells, picocells, and microcells, depending on the range and purpose of use, and should be understood as a concept encompassing all of them. Also, in LTE, a small cell is commonly referred to as a HeNB (Home eNB), and thus, the small cells 110, 130, and 150 should be understood as a concept including a HeNB. The small cells 110, 130, and 150 are based on the service purpose of the indoor / outdoor, namely, home, enterprise, urban, urban, rural, and offices. Residential) may be installed.

The UE (UE, 170, 172, 174, 176, 177, 178) may communicate with the small cells (110, 130, 150) through one or more Radio Access Technologies (RAT), such as LTE / LTE-A. The terminals 170, 172, 174, 176, 177, and 178 are GSM networks, 2G wireless communication networks such as CDMA networks, LTE / LTE-A networks, wireless Internet networks such as WiFi networks, WiBro networks, and mobile Internets such as WiMax networks. Although it may implement Radio Access Technologies (RATs) adopted in a wireless communication network supporting a network or packet transmission and may include the functions / features of a mobile communication terminal used in such a wireless communication network, the terminals 170, 172, 174 , 176, 177, and 178 are not limited thereto. Also, the terminals 170, 172, 174, 176, 177, and 178 may be a desktop or laptop PC, a tablet PC, a laptop, a note pad, a smartphone, or the like that support LTE / LTE-A. Such various types of handheld-based wireless communication devices may be included, but the types of terminals 170, 172, 174, 176, 177, and 178 are not limited thereto.

Referring to FIG. 1A, the terminals 170 and 172 are located in the service area of the small cell 110 and are wirelessly connected to the small cell 110 through a wireless link. Since the terminals 170 and 172 are wirelessly connected to the small cell 110, the small cell 110 becomes a serving small cell from the viewpoint of the terminals 170 and 172. As shown in FIG. 1A, the terminal 170 is located in a cell center region (CC region) 122, which is an area relatively close to the serving small cell 110, while the terminal 172 is located in the cell center region 122. It is located in the cell edge region (CE region) 124, which is a boundary region of a relatively long distance from the serving small cell 110. The terminals 174 and 176 are also located in the service area of the small cell 130 and are wirelessly connected to the small cell 130 through a wireless link. Since the terminals 174 and 176 are wirelessly connected to the small cell 130, the small cell 130 becomes a serving small cell in terms of the terminals 174 and 176. Similarly, terminal 174 is located in CC region 125, while terminal 176 is located in CE region 127. In this situation, the terminal 172 located in the CE region 124 is affected by the interference from the small cell 130, and the terminal 176 located in the CE region 127 is affected by the interference from the small cell 110. The effect of this interference can be exacerbated as the cell batch density increases.

According to the exemplary embodiments of the present invention, each of the small cells 110 and 130 may use a usable band (Resource) to improve throughput performance of the terminals 172 and 176 located in the CE regions 124 and 127. Blocks: RBs allocate high PDSCH (Physical Downlink Shared Channel) power to bands allocated to CE regions 124 and 127 and low PDSCH power to bands allocated to CC regions 122 and 125. In addition, according to embodiments of the present invention, the bands allocated to the CE regions 124 and 127 do not overlap between the small cells 110 and 130 adjacent to each other, and the bands allocated to the CC regions 122 and 125 are also not overlapped with each other. By not overlapping each other, the throughput performance of the terminals 172 and 176 located in the CE regions 124 and 127 is greatly increased, while the terminals 170 and 174 of the CC regions 122 and 125 are greatly increased. This allows you to maintain throughput performance almost intact.

FIG. 1B is a diagram illustrating resource block (RB) allocation patterns allocated to a CE region and a CC region by dividing a band usable in the small cells of FIG. 1A according to an embodiment of the present invention. Referring to FIG. 1B, in the small cells 110 and 130, an available band (hereinafter, referred to as an 'available RB region') includes one cell edge resource block region (CER) region and one cell center resource block region (CCR). RB allocation pattern can be used. The CER region is a band allocated to the CE regions 124 and 127 and the CCR region is a band allocated to the CC regions 122 and 125. Both the CER region and the CCR region may be separate resource block regions, and in the illustrated RB allocation patterns, the number N of RB regions is two. In one embodiment, the RB may be composed of 84 resource elements (REs). In the illustrated embodiment, the usable RB region includes a total of 100 RBs (200 MHz), but it should be appreciated that the number of RBs included in the available RB region may vary depending on the system implementation. In FIG. 1B, for example purposes, the small cell 110 uses the first RB allocation pattern 182 in which the CER region and the CCR region are concatenated, and the small cell 130 allocates the second RB in which the CCR region and the CER region are concatenated. Although shown as using a pattern 184, according to embodiments of the present invention, each of the small cells 110, 130 corresponds to a PCI subgroup of the corresponding small cell as an RB allocation pattern therefor, the first RB allocation. The RB allocation pattern may be determined to use one of the pattern and the second RB allocation pattern, or the RB allocation pattern for the small cell may be determined based on information representing the surrounding environment of the small cell. According to the 3rd Generation Partnership Project (3GPP) standard, adjacent small cells have different PCI subgroups unless PCI collision or CRS collision occurs. This ensures that small cells with the same PCI subgroup use the same RB allocation pattern and that PCI small subgroups have different small cell allocations with different RB allocation patterns, thereby ensuring that adjacent smalls use different RB allocation patterns. Can be.

In one embodiment, the PCI subgroup may be determined according to the modulo 3 value (PCI mod 3) of the Physical Cell Identifier (PCI) currently used by the corresponding small cell. The PCI of the base station is a number used to distinguish the base stations from each other, and may be allocated within the range of [0, 503] as defined in the 3GPP TS 36.331 standard. A typical operator has a maximum number of macro cells. In order to provide PCI candidates, the PCI range of the small cell is limited to 10 or less. Referring to FIG. 1E, which illustrates PCIs 91 to 99 and corresponding PCI subgroups, according to an embodiment of the present invention, for example, assuming that the small cell 110 has 91 PCIs, the module of 91 may be modified. Since the value of 3 is 1, the PCI subgroup for the small cell 110 is 1 and thus the small cell 110 may determine to use the first RB allocation pattern as the RB allocation pattern therefor. For another example, suppose the small cell 130 has a PCI of 95, since the modulo 3 value of 95 is 2, the PCI subgroup for the small cell 130 is 2 and thus the small cell 130 has an RB for it. It can be determined to use the second RB allocation pattern as the allocation pattern. For another example, a small cell with a PCI of 99 has a modulo 3 value of 3, which in this case determines the RB allocation pattern for that small cell based on information representing the surrounding environment of the small cell. Or not using a specific RB pattern for that small cell. Details thereof will be described in detail with reference to FIG. 3.

In one embodiment, the CER region of the first RB allocation pattern 182 includes 48 RBs from RB # 0, which is the first RB, to RB # 47, which is the forty eighth RB, and the first RB allocation pattern 192. The CCR region of may include 52 RBs from RB # 48 to RB # 99. In one embodiment, the CCR region of the second RB allocation pattern 184 includes 48 RBs from RB # 0 to RB # 47, and the CER region of the second RB allocation pattern 184 is RB # 48 to RB. It can contain up to 52 RBs up to # 99. In the above description, the first RB allocation pattern and the second RB allocation pattern illustrated in FIG. 1B are described as the first RB allocation pattern and the second RB allocation pattern, respectively, but the first RB allocation pattern and the second RB allocation pattern are mutually different. It is also possible to change to another pattern.

As shown, the CER region in the first RB allocation pattern 182 is shifted from the CER region in the second RB allocation pattern 184. The small cell 110 using the first RB allocation pattern 182 causes the terminal 172 located in the CE region 124 to allocate the second RB allocation pattern 184 by allocating a relatively high PDSCH power to the CER region. It is possible to perform high quality communication with less interference from the small cell 130 that uses the low PDSCH power in the CCR region. Similarly, the small cell 130 using the second RB allocation pattern 184 causes the terminal 176 located in the CE region 127 to allocate a first RB allocation pattern (C) by allocating a relatively high PDSCH power to the CER region. 182 to allow for high quality communication with less interference from the small cell 110 using low PDSCH power in its CCR region.

FIG. 1C is similar to FIG. 1A in terms of cell arrangement, but differs from the case of FIG. 1A in that the small cells 150 are further disposed so that three small cells are adjacent to each other. The terminals 177 and 178 are located in the service area of the small cell 150 and are wirelessly connected to the small cell 150 through a wireless link. Since the terminals 177 and 178 are wirelessly connected to the small cell 150, the small cell 150 becomes a serving small cell from the perspective of the terminals 177 and 178. As shown in FIG. 1C, the terminal 178 is located in the CC region 128, which is an area relatively close to the serving small cell 150, while the terminal 177 is relatively from the serving small cell 150. It is located in the CE area 129 which is a boundary area of a long distance. In this situation, the terminal 172 located in the CE region 124 is affected by the interference from the small cell 130 and the small cell 150, and the terminal 176 located in the CE region 127 is the small cell 110. ) And the terminal 177 located in the CE region 129 under the interference from the small cell 150 are affected by the interference from the small cell 110 and the small cell 130. As the cell batch density increases, it can get worse.

According to embodiments of the present invention, each of the small cells 110, 130, 150 is usable to improve throughput performance of the terminals 172, 176, 177 located in the CE region 124, 127, 129. A relatively high PDSCH power is allocated to a band allocated to the CE regions 124, 127, and 129 among the bands RBs, and a low PDSCH power is allocated to a band allocated to the CC regions 122, 125, and 128. In addition, according to embodiments of the present invention, the bands allocated to the CE regions 124, 127, and 129 between the small cells 110, 130, and 150 adjacent to each other do not overlap each other, and the CC regions 122, 125, and 128 are not overlapped with each other. By not overlapping the bands allocated to each other, the throughput performance of the terminals 172, 176, and 177 located in the CE regions 124, 127, and 129 is greatly increased, while the CC regions 122, 125, and 128 are increased. Throughput performance of the located terminals 170, 174, 178 can be maintained almost intact.

FIG. 1D is a diagram illustrating RB allocation patterns allocated to one CE region and two CC regions by dividing an available RB region available in the small cells of FIG. 1C according to an embodiment of the present invention. Referring to FIG. 1D, in the small cells 110, 130, and 150, an RB allocation pattern obtained by dividing an available RB region into one CER region and two CCR regions may be used. The CER region is a band allocated to the CE regions 124, 127, and 129, and the CCR region is a band allocated to the CC regions 122, 125, and 128. Both the CER region and the CCR region may be separate RB regions, and in the illustrated RB allocation patterns, the number N of RB regions is three. In the illustrated embodiment, the usable RB region includes a total of 100 RBs (200 MHz), but it should be appreciated that the number of RBs included in the available RB region may vary depending on the system implementation. In FIG. 1D, for example purposes, the small cell 110 uses a first RB allocation pattern 192 concatenated with a CER region, a first CCR region, and a second CCR region, and the small cell 130 is a first CCR region; The third RB allocation pattern 196 using the second RB allocation pattern 194 in which the CER region and the second CCR region are concatenated, and the small cell 150 is concatenated in the first CCR region, the second CCR region and the CER region. According to the embodiments of the present invention, each of the small cells 110, 130, and 150 corresponds to a PCI subgroup of the corresponding small cell as an RB allocation pattern thereof. The RB allocation pattern of any one of 192 to third RB allocation pattern 196 may be used. As described above, the PCI subgroup may be determined according to the PCI value 3 (PCI mod 3) of the PCI that the small cell is currently using. Referring to FIG. 1E, for example, assuming that the small cell 110 has a PCI of 91, since the modulo 3 value of 91 is 1, the PCI subgroup for the small cell 110 is 1 and thus the small cell ( 110 may determine to use the first RB allocation pattern 192 as an RB allocation pattern therefor. For another example, suppose the small cell 130 has a PCI of 92 and the modulo 3 value of 92 is 2, so the PCI subgroup for the small cell 130 is 2 and thus the small cell 130 has an RB for it. It may be determined to use the second RB allocation pattern 194 as the allocation pattern. For another example, suppose the small cell 150 has a PCI of 93, since the modulo 3 value of 93 is 3, the PCI subgroup for the small cell 150 is 3 and thus the small cell 150 has It may be determined to use the third RB allocation pattern 196 as the RB allocation pattern.

In one embodiment, the CER region of the first RB allocation pattern 192 includes 32 RBs from RB # 0 to RB # 31, and the first CCR region of the first RB allocation pattern 192 is RB # 32. 32 RBs from RB # 63 to the second CCR region of the first RB allocation pattern 192 may include 36 RBs from RB # 64 to RB # 99. In one embodiment, the first CCR region of the second RB allocation pattern 194 includes 32 RBs from RB # 0 to RB # 31, and the CER region of the second RB allocation pattern 194 is RB # 32. To 32 RBs from RB # 63, and the second CCR region of the second RB allocation pattern 194 may include 36 RBs from RB # 64 to RB # 99. In one embodiment, the first CCR region of the third RB allocation pattern 196 includes 32 RBs from RB # 0 to RB # 31, and the second CCR region of the third RB allocation pattern 196 is an RB. 32 RBs from # 32 to RB # 63, and the CER region of the third RB allocation pattern 196 may include 36 RBs from RB # 64 to RB # 99. In the above description, the first RB allocation pattern to the third RB allocation pattern illustrated in FIG. 1D are described as the first RB allocation pattern to the third RB allocation pattern, respectively, but the first RB allocation pattern to the third RB allocation pattern are mutually selected. It is also possible to change to another pattern.

As shown, the CER region in the first RB allocation pattern 192 is shifted from the CER region in the second RB allocation pattern 194 and the CER region in the third RB allocation pattern 196. The small cell 110 using the first RB allocation pattern 192 allows the terminal 172 located in the CE region 124 to allocate the second RB allocation pattern 194 by allocating a relatively high PDSCH power to the CER region. From the small cell 130 using the low PDSCH power to the first CCR region and from the small cell 150 using the third RB allocation pattern 196 and assigning the low PDSCH power to the first CCR region. It provides less interference and high quality communication. Similarly, the small cell 130 using the second RB allocation pattern 194 causes the terminal 176 located in the CE region 127 to allocate the first RB allocation pattern (1) by allocating a relatively high PDSCH power to the CER region. Small cell 110 using 192 and allocating low PDSCH power to its first CCR region and small cell 150 using third RB allocation pattern 196 and allocating low PDSCH power to its second CCR region; This allows for high quality communication with less interference. Similarly, the small cell 150 using the third RB allocation pattern 196 causes the terminal 177 located in the CE region 129 to allocate the first RB allocation pattern (C) by assigning a relatively high PDSCH power to the CER region. The small cell 110 using 192 and allocating low PDSCH power to the second CCR region and the small cell 130 using the second RB allocation pattern 194 and allocating low PDSCH power to the second CCR region. This allows for high quality communication with less interference.

2 is a block diagram of a small cell in which a resource management device for controlling interference between small cells in a mobile communication network according to an embodiment of the present invention and a block diagram of a terminal according to an embodiment of the present invention are shown. Drawing.

As shown in FIG. 2, the small cell 110 may include a Self Organization Network (SON) module 242, a control and communication module 244, and a storage module 249. Although FIG. 2 illustrates the SON module 242 and the control and communication module 244 as separate modules, it should be appreciated that they can be implemented as one integrated module. The components shown in FIG. 2 do not reflect all the functions of the small cell 110 and are not essential, so the small cell 110 includes more or less components than the components shown. Be aware that you can.

The control and communication module 244 may be configured to implement an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) protocol stack. The protocol stack 248 includes a Radio Resource Management (RRM) layer, a Radio Resource Control (RRC) layer, a Packet Data Convergence Control (PDCP) layer, a Radio Link Control (RLC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) physical. Layer) may include a layer (not shown). Since these layers are well-known components, their detailed description is omitted. The protocol stack 248 of the control and communication module 244 is hardware and / or implements various RATs, including LTE / LTE-A, that enables the terminal 170 to communicate wirelessly with the small cell 110. Or may be implemented in firmware. In one embodiment, the PHY layer of protocol stack 248 may be implemented to conform to a wireless communication interface specification such as LTE-Ue.

The SON module 242 corresponds to the PCI subgroup of the small cell 110 as the RB allocation pattern for the small cell 110 when the number N of RB regions is given as three. It may be configured to determine to use the RB allocation pattern of any one of the 1 RB allocation pattern 192 to the third RB allocation pattern 196. The SON module 242 may be further configured to identify the PCI subgroup of the small cell 110 according to the value 3 (PCI mod 3) of the PCI that the small cell 110 is currently using. The SON module 242 determines that the first RB allocation pattern 192 is used as the RB allocation pattern for the small cell 110 when the PCI subgroup of the small cell 110 is 1, and the small cell 110 is determined. If the PCI subgroup of 2 is 2, it is determined to use the second RB allocation pattern 194 as the RB allocation pattern for the small cell 110. If the PCI subgroup of the small cell 110 is 3, the small cell ( It may be further configured to determine to use the third RB allocation pattern 196 as the RB allocation pattern for 110. In one embodiment, the first RB allocation pattern 192 is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated, and the second RB allocation pattern 194 is a first CCR region, a CER region, and a first CCR region. The two CCR regions may be concatenated, and the third RB allocation pattern 196 may be a pattern in which the first CCR region, the second CCR region, and the CER region are concatenated.

The SON module 242 is a small RB allocation pattern for the small cell 110 when the PCI subgroup of the small cell 110 is not 3 when the number N of RB regions is given as 2. Determine to use one of the RB allocation patterns of the first RB allocation pattern 182 and the second RB allocation pattern 184, corresponding to the PCI subgroup of the cell 110, and determine the PCI of the small cell 110 When the subgroup is 3, the subgroup may be configured to determine an RB allocation pattern for the small cell 110 based on information representing the environment of the small cell 110. The SON module 242 determines that the first RB allocation pattern 182 is used as the RB allocation pattern for the small cell 110 when the PCI subgroup of the small cell 110 is 1, and determines that If the PCI subgroup is 2 may be further configured to determine to use the second RB allocation pattern 184 as the RB allocation pattern for the small cell. In an embodiment, the first RB allocation pattern 182 may be a pattern in which the CER region and the CCR region are concatenated, and the second RB allocation pattern 184 may be a pattern in which the CCR region and the CER region are concatenated.

In one embodiment, the SON module 242 acts as the highest interference source for the small cell 110 such that the PCI subgroups of adjacent small cells recorded in the neighbor relation table (NRT) of the small cell 110 are selected. When the neighbor small cell having a RSRP higher than 1 and a difference between the RSRP of the neighbor small cell and the predetermined threshold value N_RSRP_th and the PCI subgroup is 2 is not recorded in the NRT of the small cell 110, the small cell 110 May be further configured to determine to use the second RB allocation pattern 184 as the RB allocation pattern for. In one embodiment, SON module 242 acts as the highest interference source for small cell 110 such that the PCI subgroup of adjacent small cells recorded in the NRT of small cell 110 is 2 and the adjacent small RB for small cell 110 when adjacent small cell with RSRP higher than the difference between RSRP of cell and the predetermined threshold N_RSRP_th and PCI subgroup 1 is not recorded in NRT of small cell 110 It may be further configured to determine to use the first RB allocation pattern 182 as the allocation pattern.

When the RB allocation pattern to be used for the small cell 110 in the SON module 242 is determined, the SON module 242 determines that the terminal 170 performs CE based on the CQI (Channel Quality Information) information received from the terminal 170. It may be configured to determine whether it is in the region or the CC region. The SON module 242 may be configured to transmit a command to the MAC layer and the RLC layer of the protocol stack 248 to allocate only specific RBs of the CER region to the terminal 170 when the terminal 170 determines that the terminal 170 is in the CE region. have. For example, when it is determined that the small cell 110 uses the first RB allocation pattern 182, the SON module 242 may transmit a command to allocate only RBs from RB # 0 to RB # 47 to the terminal 170. have. As another example, when it is determined that the small cell 110 uses the second RB allocation pattern 194, the SON module 242 may instruct the terminal 170 to allocate only RBs from RB # 32 to RB # 63. I can deliver it. The SON module 242 may also be further configured to convey information to the MAC layer and the RLC layer of the protocol stack 248 with the above command about how much PDSCH power for the terminal 170 should be. The protocol stack 248 may be configured to actually allocate RBs to the terminal 170 in consideration of the command / information received from the SON module 242 and the amount of trapping required by the terminal 170.

The storage module 249 may store programs and / or data for the operation of the control and communication module 244, information about PCI currently used by the small cell 110, and NRT, data input / output, and the like. Can also be stored. The storage module 249 may include a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (eg, SD or XD memory, etc.), Random Access Memory (RAM), Static Random Access Memory (SRAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Programmable Read-Only Memory (PROM) Magnetic Memory, Magnetic It may include a storage medium of at least one type of a disk, an optical disk.

The terminal 170 shown in FIG. 2 may include a control and communication module 224 and a storage module 226. The components illustrated in FIG. 2 do not reflect all the functions of the terminal 170 and are not essential, and thus the terminal 170 may include more or less components than those shown. It should be recognized.

The control and communication module 224 of the terminal 170 may also be configured to implement the E-UTRAN protocol stack 228 like the control and communication module 244 of the small cell 110. The protocol stack 228 of the control and communication module 224 is each as an RRC layer, PDCP layer, RLC layer, MAC layer and PHY layer and peer layers of the protocol stack 248 of the control and communication module 244. It may include an operating RRC layer, PDCP layer, RLC layer, MAC layer and PHY layer (not shown). Since these layers are well-known components, their detailed description is omitted. The protocol stack 228 may be configured to control the wireless connection to the small cell 110 and the overall operation of the terminal 170. The protocol stack 228 may be implemented with hardware modules and / or software / firmware modules, for example, for performing control and processing for voice calls, data communications, video calls, and the like. In one embodiment, the PHY layer of protocol stack 228 may be designed to implement various RATs, including LTE / LTE-A.

The storage module 226 can store programs and / or data for the operation of the protocol stack 228, and can also store input / output data and the like. The storage module 226 may be implemented as a memory device as described above in connection with the storage module 249 of the small cell 110. The storage module 226 may include, for example, a ROM, an EPROM, an EEPROM, or the like, but may include various memory devices. In one embodiment, the terminal 170 is configured to operate in conjunction with a web storage that performs a storage function on the Internet separately from or in conjunction with the storage module 226. Can be.

In the above-described embodiment, the control and communication module 244 of the small cell 110 and the control and communication module 224 of the terminal 170 may include ASICs (application specific integrated circuits) and DSPs (in terms of hardware). digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, and microprocessors In addition, embodiments that include a procedure, step, or function may be implemented as firmware / software modules executable on a hardware platform to perform at least one function or operation. The software code may be implemented by a software application written in a suitable programming language, in which case the software code may be Modules may be stored dispersed on a (249, 226) or stored in a storage module (249, 226) and the control and communication module (244, 224) and executed by a control and communications module (244, 224).

3A and 3B illustrate an embodiment of a flowchart for describing a resource management method for controlling interference between small cells in a mobile communication network.

The method may be implemented in any small cell of the small cells 110, 130, 150 shown in FIGS. 1A and 1C, but in the following description, these small cells are referred to as 'small cell 110' for convenience of description. Shall be. The method starts with the step (S305) of receiving the number (N) of RB regions (Resource Block Regions). N can be 2 or 3. When N is 2, the first RB allocation pattern or the second RB allocation pattern is obtained by dividing the available RB region into one CER (Cell Edge Resource Block Region) region and one CCR (Cell Center Resource Block Region) region. This is the case when no specific RB allocation pattern is used. In one embodiment, the available RB region may consist of a total of 100 RBs (200 MHz). In one embodiment, the first RB allocation pattern is a concatenation of a CER region including RB # 0, which is the first RB, and RB # 47, which is an forty eighth RB, and a CCR region, which includes RB # 48, which is R48 # 99 The second RB allocation pattern may be a pattern in which a CCR region including RB # 0 to RB # 47 and a CER region including RB # 48 to RB # 99 are concatenated. In another embodiment, the first RB allocation pattern is a pattern in which a CCR region including RB # 0 to RB # 47 and a CER region including RB # 48 to RB # 99 are concatenated, and the second RB allocation pattern is The CER region including RB # 0 to RB # 47 and the CCR region including RB # 48 to RB # 99 may be a concatenated pattern. When N is 3, any one of the first RB allocation pattern to the third RB allocation pattern which divides the available RB region into one CER region and two CCR regions (first CCR region and second CCR region) is used. If it is. In one embodiment, the first RB allocation pattern includes a CER region including RB # 0 to RB # 31, a first CCR region including RB # 32 to RB # 63, and RB # 64 to RB # 99. A first CCR region including a second CCR region including a concatenated second RB allocation pattern, a first CCR region including RB # 0 to RB # 31, a CER region including RB # 32 to RB # 63, and The second CCR region including RB # 64 to RB # 99 is a second pattern concatenated, and the third RB allocation pattern is a first CCR region including RB # 0 to RB # 31, and RB # 32 to RB. The second CCR region including up to # 63 and the CER region including from RB # 64 to RB # 99 may be a third pattern concatenated. In another embodiment, the first RB allocation pattern may be a first pattern, the second RB allocation pattern may be a third pattern, and the third RB allocation pattern may be a second pattern. In another embodiment, the first RB allocation pattern may be a second pattern, the second RB allocation pattern may be a first pattern, and the third RB allocation pattern may be a third pattern. In another embodiment, the first RB allocation pattern may be a second pattern, the second RB allocation pattern may be a third pattern, and the third RB allocation pattern may be a first pattern. In another embodiment, the first RB allocation pattern may be a third pattern, the second RB allocation pattern may be a first pattern, and the third RB allocation pattern may be a second pattern. In another embodiment, the first RB allocation pattern may be a third pattern, the second RB allocation pattern may be a second pattern, and the third RB allocation pattern may be a first pattern.

In operation S310, the small cell 110 is booted up, the physical cell identifier (PCI) of the small cell 110 is changed, or the neighbor relation table (NRT) inside the small cell 110 is updated. Check if it is. If the small cell 110 is not in the boot-up state and the PCI of the small cell 110 is not changed and it is determined that the NRT in the small cell 110 is not updated in step S310, the small cell 110 is not updated. Return to to wait for one of the above events to occur. If it is determined in step S310 that one of the above events has occurred, the process proceeds to step S315 to check whether a PCI collision or a CRS collision has occurred. In one embodiment, the CRS collision may mean a CRS collision with the small cell 110 and the adjacent small cell closest to each other in consideration of a high density cell arrangement. PCI collision occurs when the small cell 110 and the adjacent small cell adjacent to it use the same PCI, in which case the PCI of the small cell 110 and the adjacent small cell adjacent to it, for example the same mod 3 subgroup This means that the small cell 110 and the adjacent small cell adjacent to the same use the same RB allocation pattern, and thus the effect of inter-cell interference control according to the present invention cannot be obtained. CRS collision is when small cell 110 and adjacent small cells carry CRS in the same resource elements (REs), in other words they do not use the same PCI but nevertheless their PCIs belong to the same mod 3 subgroup. In this case, even when a CRS collision occurs, since the small cell 110 and the adjacent small cells adjacent to each other use the same RB allocation pattern, the effect of the inter-cell interference control according to the present invention cannot be obtained. Therefore, in case of PCI collision or CRS collision, using a specific RB pattern is meaningless in terms of resource management. For this reason, this step is to prevent useless resource management by not using a specific RB allocation pattern in case of PCI collision or CRS collision. If it is determined that the PCI collision or the CRS collision has occurred as a result of the check in step S315, the process returns to step S310. If it is determined that the PCI collision did not occur and the CRS collision did not occur as a result of the check in step S315, the process proceeds to step S320 to check whether N is three. If it is determined in step S320 that N is 3, the process proceeds to step S355. In step S355, the small cell 110 determines a subgroup (PCI subgroup) to which the PCI currently being used belongs and determines to use an RB allocation pattern corresponding to the subgroup. For example, when the PCI used by the small cell 110 is 497, since 497 mod 3 is 2, it is determined that the subgroup is 2 and uses the second RB allocation pattern corresponding to the RB allocation pattern. After the RB allocation pattern is determined in step S355, the process returns to step S310.

On the other hand, if it is determined in step S320 that N is not 3 but 2, the process may be performed because 1: 1 mapping between the PCI subgroup of the small cell 110 and the RB allocation pattern may or may not be possible. We first check whether the PCI subgroup is 3 or not. If it is determined in step S325 that the PCI subgroup is not 3, since there is an RB allocation pattern that may be mapped 1: 1, the process proceeds to step S355 to determine the RB allocation pattern. That is, when the PCI subgroup is 1, it is determined to use the corresponding RB allocation pattern, for example, the first RB allocation pattern, and when the PCI subgroup is 2, the corresponding RB allocation pattern, for example, the second RB allocation pattern is used. Can be determined. If the RB allocation pattern is determined, the process returns to step S310. If it is determined in step S325 that the PCI subgroup is 3, there is no RB allocation pattern that can be mapped 1: 1 (i.e., two PCI cells are preferentially allocated to adjacent small cells having 1 and 2). Since the RB allocation patterns are each allocated), the RB allocation pattern may be determined by identifying the surrounding environment. In this case, the process proceeds to step S330 to search for the NRT inside the small cell 110 to determine the adjacent small cell serving as the highest interference source with respect to the small cell 110 at present, and to determine the PCI sub-channel of the small neighbor cell. Check whether the group is 1 or not. In one embodiment, the adjacent small cell serving as the highest interference source for the small cell 110 may be determined as the small cell recorded as having the highest RSRP (Reference Signal Received Power) in the NRT of the small cell 110. have.

If it is determined in step S330 that the PCI subgroup of the adjacent small cell serving as the highest interference source is 1, the process proceeds to step S335 and acts as the highest interference source found in step S330. A neighboring small cell having an RSRP higher than a difference between RSRP of a neighboring small cell of which the PCI subgroup is 1 and a threshold value N_RSRP_th, and whether the neighboring small cell of which the PCI subgroup is 2 is in the NRT is checked. If there is a neighboring small cell with a PCI subgroup of 2 that acts as the highest interference source and has an RSRP comparable to the RSRP of a neighboring small cell whose PCI subgroup is 1, then the first RB allocation pattern is used. Since it is possible to estimate that there are both neighbor small cells and neighbor small cells using the second RB allocation pattern, neighbor neighbor small cells using the first RB allocation pattern, the second RB allocation pattern, or in any case. This is because it does not use a specific RB allocation pattern because it is interfered with. As a result of the check in step S335, the neighboring small cell serving as the highest interference source and having a RSRP higher than the difference between the RSRP of the neighboring small cell whose PCI subgroup is 1 and the threshold value N_RSRP_th is 2, and the PCI subgroup is 2 If it is determined that the adjacent small cell is in the NRT, the process returns to step S310 without determining to use a specific RB allocation pattern. As a result of the check in step S335, the neighboring small cell serving as the highest interference source and having a RSRP higher than the difference between the RSRP of the neighboring small cell whose PCI subgroup is 1 and the threshold value N_RSRP_th is 2, and the PCI subgroup is 2 If it is determined that the neighbor small cell is not in the NRT, RB allocation is performed in step S340. Since the PCI subgroup of the neighboring small cell serving as the highest interference source for the NRT is 1, it is possible to estimate that the neighboring small cell uses the first RB allocation pattern, and therefore, to avoid interference with the neighboring small cell, It is determined to use the second RB allocation pattern as the RB allocation pattern for 110). When the RB allocation is completed, the process returns to step S310.

If it is determined in step S330 that the PCI subgroup of the adjacent small cell serving as the highest interference source is 2, the process proceeds to step S345 to act as the highest interference source found in step S330. A neighboring small cell having an RSRP higher than a difference between RSRP of a neighboring small cell whose PCI subgroup is 2 and a threshold value N_RSRP_th, and whether the neighboring small cell whose PCI subgroup is 1 is in the NRT are examined. If there is a neighboring small cell with PCI subgroup 1 that has the RSRP comparable to the RSRP of the neighboring small cell whose PCI subgroup is 2, and that PCI subgroup is 2, the first RB allocation pattern is used. Since it is possible to estimate that there are both neighbor small cells and neighbor small cells using the second RB allocation pattern, neighbor neighbor small cells using the first RB allocation pattern, the second RB allocation pattern, or in any case. This is because it does not use a specific RB allocation pattern because it is interfered with. As a result of the inspection in step S345, the neighboring small cell serving as the highest interference source and having a RSRP higher than the difference between the RSRP of the neighboring small cell whose PCI subgroup is 2 and the threshold value N_RSRP_th, whose PCI subgroup is 1 If it is determined that the adjacent small cell is in the NRT, the process returns to step S310 without determining to use a specific RB allocation pattern. As a result of the inspection in step S345, the neighboring small cell serving as the highest interference source and having a RSRP higher than the difference between the RSRP of the neighboring small cell whose PCI subgroup is 2 and the threshold value N_RSRP_th, whose PCI subgroup is 1 If it is determined that the adjacent small cell is not in the NRT, RB allocation is performed in step S350. Since the PCI subgroup of the neighboring small cell serving as the highest interference source for the NRT is 2, it is possible to estimate that the neighboring small cell uses the second RB allocation pattern and thus to avoid interference with the neighboring small cell. It is determined to use the first RB allocation pattern as the RB allocation pattern for 110). When the RB allocation is completed, the process returns to step S310.

In the embodiments disclosed herein, the arrangement of the components shown may vary depending on the environment or requirements on which the invention is implemented. For example, some components may be omitted or several components may be integrated and implemented as one. In addition, the arrangement order and connection of some components may be changed.

Although various embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described specific embodiments, and the above-described embodiments deviate from the gist of the present invention as claimed in the appended claims. Without departing from the scope of the present invention pertains to those skilled in the art, various modifications may be made to those skilled in the art, and such modified embodiments should not be understood separately from the technical spirit or scope of the present invention. Accordingly, the technical scope of the present invention should be defined only by the appended claims.

110, 130, 150: small cell
170, 172, 174, 176, 177, 178: terminal
122, 125, 128: CC area
124, 127, 129: CE zone
182 and 192: first RB allocation area
184, 194: second RB allocation area
196: third RB allocation area
224: control and communication module
228: protocol stack
226: storage module
242: SON module
244: control and communication module
248: protocol stack
249: storage module

Claims (26)

As a resource management method in a small cell,
Receiving the number N of RB regions (Resource Block Regions), and
When N is 3, the RB allocation pattern of one of the first RB allocation pattern and the third RB allocation pattern, corresponding to the Physical Cell Identifier (PCI) subgroup of the small cell, is used as the RB allocation pattern for the small cell. Determining to use;
The PCI subgroup is determined according to the modulo 3 value (PCI mod 3) of PCI that the small cell is currently using.
The method of claim 1,
The determining may include determining that the first RB allocation pattern is used as the RB allocation pattern for the small cell when the PCI subgroup of the small cell is 1, and wherein the PCI subgroup of the small cell is 2 It is determined that the second RB allocation pattern is used as the RB allocation pattern for the small cell, and when the PCI subgroup of the small cell is 3, the third RB allocation pattern is used as the RB allocation pattern for the small cell. And determining to do so.
The method of claim 2,
The first RB allocation pattern is a pattern in which a Cell Edge Resource Block Region (CER) region, a first Cell Center Resource Block Region (CCR) region, and a second CCR region are concatenated in that order.
The second RB allocation pattern is a pattern in which the first CCR region, the CER region and the second CCR region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated in that order.

The method of claim 2,
The first RB allocation pattern is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated in that order.
The second RB allocation pattern is a pattern in which the first CCR region, the second CCR region, and the CER region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated in that order.

The method of claim 2,
The first RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated in that order.
The second RB allocation pattern is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated in that order.
The method of claim 2,
The first RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated in that order.
The second RB allocation pattern is a pattern in which the first CCR region, the second CCR region, and the CER region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated in that order.

The method of claim 2,
The first RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated in that order.
The second RB allocation pattern is a pattern in which the first CCR region, the CER region and the second CCR region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated in that order.

The method of claim 2,
The first RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated in that order.
The second RB allocation pattern is a pattern in which a CER region, a first CCR region, and a second CCR region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated in that order.

The method of claim 1,
The determining may be performed when the small cell is booted up, when the PCI of the small cell is changed, or when the neighbor relation table (NRT) inside the small cell is updated.
The method of claim 9,
The determining may be performed when no PCI collision or CRS collision occurs.
As a resource management method in a small cell,
Checking whether the PCI subgroup of the small cell is 3;
When it is determined that the PCI subgroup of the small cell is not 3, any one of a first RB allocation pattern and a second RB allocation pattern corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell is determined. Determining to use an RB allocation pattern, and
If it is determined that the PCI subgroup of the small cell is 3, determining the RB allocation pattern for the small cell based on the information representing the surrounding environment of the small cell;
The PCI subgroup is determined according to the modulo 3 value (PCI mod 3) of PCI that the small cell is currently using.
The method of claim 11,
The determining of using the RB allocation pattern of any one of a first RB allocation pattern and a second RB allocation pattern corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell may include: If the PCI subgroup of 1 is 1, it is determined that the first RB allocation pattern is used as the RB allocation pattern for the small cell. If the PCI subgroup of the small cell is 2, it is determined as the RB allocation pattern for the small cell. Determining to use the second RB allocation pattern.
The method of claim 12,
The first RB allocation pattern is a pattern in which a CER region and a CCR region are concatenated in that order.
And the second RB allocation pattern is a pattern in which a CCR region and a CER region are concatenated in that order.

The method of claim 12,
The first RB allocation pattern is a pattern in which a CCR region and a CER region are concatenated in that order.
And the second RB allocation pattern is a pattern in which a CER region and a CCR region are concatenated in that order.

The method of claim 11,
Checking whether the PCI subgroup of the small cell is 3, wherein any one of a first RB allocation pattern and a second RB allocation pattern corresponding to the PCI subgroup of the small cell as an RB allocation pattern for the small cell; Determining to use an RB allocation pattern and determining an RB allocation pattern for the small cell based on the information representing the surrounding environment of the small cell, wherein the small cell is a boot-up state or PCI of the small cell Is performed when is changed or the NRT inside the small cell is updated.
The method of claim 15,
Checking whether the PCI subgroup of the small cell is 3, wherein any one of a first RB allocation pattern and a second RB allocation pattern corresponding to the PCI subgroup of the small cell as an RB allocation pattern for the small cell; Determining that the RB allocation pattern is to be used and determining the RB allocation pattern for the small cell based on the information indicating the surrounding environment of the small cell is performed when no PCI collision or CRS collision occurs. Resource management method.
The method of claim 11,
Determining the RB allocation pattern for the small cell based on the information indicating the surrounding environment of the small cell
Checking whether the PCI subgroups of neighboring small cells recorded in the NRT of the small cell are 1 or 2, serving as the highest interference sources for the small cells,
If it is determined that the PCI subgroup of the neighbor small cell is 1, the neighbor small cell having a RSRP higher than a difference between a reference signal received power (RSRP) and a predetermined threshold value of the neighbor small cell and having a PCI subgroup of 2 is the small. Checking whether it is recorded in the NRT of the cell, and
As an RB allocation pattern for the small cell when it is determined that the neighbor small cell having a RSRP higher than the RSRP of the neighbor small cell and a predetermined threshold and the PCI subgroup is 2 is not recorded in the NRT of the small cell. Determining to use the second RB allocation pattern.
The method of claim 17,
Determining the RB allocation pattern for the small cell based on the information indicating the surrounding environment of the small cell
If it is determined that the PCI subgroup of the neighbor small cell is 2, the neighbor small cell having a RSRP higher than the difference between the RSRP of the neighbor small cell and the predetermined threshold and the PCI subgroup of 1 is written to the NRT of the small cell. Checking whether it is present, and
RB allocation pattern for the small cell when it is determined that a neighbor small cell having a RSRP higher than the difference between the RSRP of the neighbor small cell and the predetermined threshold and having a PCI subgroup of 1 is not recorded in the NRT of the small cell And determining to use the first RB allocation pattern as a resource management method.
An apparatus for resource management in a small cell,
A storage unit which stores information regarding PCI currently used by the small cell, and
A processor configured to determine to use any one of a first RB allocation pattern to a third RB allocation pattern, corresponding to the PCI subgroup of the small cell as an RB allocation pattern for the small cell,
And the processor is further configured to identify the PCI subgroup of the small cell according to the modulo 3 value (PCI mod 3) of the PCI stored in the storage.
The method of claim 19,
The processor determines that the first RB allocation pattern is used as the RB allocation pattern for the small cell when the PCI subgroup of the small cell is 1, and the small when the PCI subgroup of the small cell is 2 Determine that the second RB allocation pattern is used as a RB allocation pattern for a cell, and when the PCI subgroup of the small cell is 3, use the third RB allocation pattern as an RB allocation pattern for the small cell. Further configured to determine.
The method of claim 20,
The first RB allocation pattern is a pattern in which a Cell Edge Resource Block Region (CER) region, a first Cell Center Resource Block Region (CCR) region, and a second CCR region are concatenated in that order.
The second RB allocation pattern is a pattern in which a first CCR region, a CER region, and a second CCR region are concatenated in that order.
And the third RB allocation pattern is a pattern in which a first CCR region, a second CCR region, and a CER region are concatenated in that order.

An apparatus for resource management in a small cell,
A storage unit which stores information regarding PCI currently used by the small cell, and
RB allocation pattern of any one of a first RB allocation pattern and a second RB allocation pattern, corresponding to the PCI subgroup of the small cell as the RB allocation pattern for the small cell when the PCI subgroup of the small cell is not 3 And a processor configured to determine an RB allocation pattern for the small cell based on information indicative of the surrounding environment of the small cell when the PCI subgroup of the small cell is 3;
And the processor is further configured to identify the PCI subgroup of the small cell according to the modulo 3 value (PCI mod 3) of the PCI stored in the storage.
The method of claim 22,
The processor determines that the first RB allocation pattern is used as the RB allocation pattern for the small cell when the PCI subgroup of the small cell is 1, and the small when the PCI subgroup of the small cell is 2 And determine to use the second RB allocation pattern as an RB allocation pattern for a cell.
The method of claim 23,
The first RB allocation pattern is a pattern in which a CER region and a CCR region are concatenated in that order.
And the second RB allocation pattern is a pattern in which a CCR region and a CER region are concatenated in that order.

The method of claim 22,
The processor acts as the highest interference source for the small cell, and the RSRP of the neighbor small cell recorded in the small cell NRT is 1 and is higher than the difference between the RSRP of the neighbor small cell and a predetermined threshold. And if an adjacent small cell having a PCI subgroup of 2 is not recorded in the small cell's NRT, the apparatus further configured to determine to use the second RB allocation pattern as an RB allocation pattern for the small cell. .
The method of claim 25,
The processor acts as the highest interference source for the small cell such that the PCI subgroup of adjacent small cells recorded in the NRT of the small cell is 2 and is higher than the difference between the RSRP of the adjacent small cell and the predetermined threshold. Further configured to determine to use the first RB allocation pattern as an RB allocation pattern for the small cell if an adjacent small cell having RSRP and PCI subgroup 1 is not recorded in the NRT of the small cell, Device.

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