KR20130028624A - Method and system for automated assigning of physical cell identity - Google Patents

Abstract

The present invention relates to a method and system for automatically allocating a physical cell identity (PCI), which is one of the initial setting values of a base station. The PCI automatic allocation system of the present invention collects information necessary for PCI allocation and neighbor cell list (NCL) configuration, determines a PCI of a base station using at least one PCI determination method, and at least one PCI In conjunction with the decision method, the neighbor cell list is set.

Description

PCI automatic allocation method and system {METHOD AND SYSTEM FOR AUTOMATED ASSIGNING OF PHYSICAL CELL IDENTITY}

The present invention relates to the field of Long Term Evolution (LTE), and more particularly, to a method and system for automatically allocating a physical cell identity (PCI), which is one of the initial setting values of a base station.

As the mobile communication market demands high speed data, coverage of base stations is gradually decreasing. Network operators need more base stations in the same area for high quality data services and are expensive to install and maintain multiple base stations. That is, a large number of people and time are required to determine the wired and wireless parameters. Since it is not easy to find the optimal conditions for the variable location of the base station and the changing wireless environment, the self-organizing network (SON) is needed to automatically install the base station and the network and adapt to the changing wireless and data traffic environments. .

PCI (Physical Cell Identity) is the most basic parameter to configure the base station. The base station performs a random sequence generation, a synchronization signal generation, a subcarrier mapping of a downlink reference signal using a PCI, and the like.

The wireless network operator configures each PCI according to which cells are configured around the base station, and accordingly, configures a neighbor cell list (NCL). According to a conventional method of configuring PCI and NCL, a base station The NCL was configured by manual rather than silent installation. A component of the NCL is composed of PCI used by neighboring cells, and the terminal performing the handover may increase the handover speed by searching the limited PCI by receiving the NCL from a serving cell.

As the mobile communication market demands small cell coverage, more base stations are required to provide quality services in the same area, and cost is required to install and maintain multiple base stations. In this situation, it is difficult to manually set PCI and NCL each time at base station installation. Moreover, in case of small base stations such as femtocells, more base stations are expected to be installed, the base stations should be freely turned on and off, and the mobility of the base stations should be guaranteed. In this case, manually installing PCI and NCL must be a complex process as well as a cost issue. Therefore, there is a need for a method of automatically setting the PCI and NCL of the base station.

Korean Patent Publication No. 10-2010-0098994 (published Sep. 10, 2010)

The present invention relates to a method and system for automatically allocating a physical cell identity (PCI), which is one of the initial setting values of a base station.

PCI automatic allocation system of the present invention, the information collection unit for collecting information necessary for PCI allocation and neighbor cell list (NCL) configuration; A PCI allocator configured to determine PCI using at least one PCI determination method; And an NCL component configured to set the neighbor cell list in association with the PCI determination method used by the PCI allocator.

In addition, the PCI automatic allocation method of the present invention comprises the steps of: collecting information necessary for PCI allocation and neighbor cell list (NCL) configuration; Determining PCI of the base station using at least one PCI determination method; And setting the neighbor cell list in association with the at least one PCI determination method.

According to the present invention, it is possible to easily perform the installation and maintenance of the base station by automatically setting the physical cell identity (PCI) and neighbor cell list (NCL), which are basic parameters set in the base station, and can be economically performed at low cost. Can be.

1 is a block diagram showing a configuration of a mobile communication system according to an embodiment of the present invention;
2 is an exemplary view showing a PCI collision phenomenon according to an embodiment of the present invention.
3 is an exemplary view showing a PCI confusion phenomenon according to an embodiment of the present invention.
4 is an exemplary view showing an OAM subsystem according to an embodiment of the present invention.
5 is a block diagram showing a configuration of an information collector according to an embodiment of the present invention.
6 is an exemplary view showing a configuration of a network according to an embodiment of the present invention.
7 is an exemplary view showing a configuration for evaluating a micro base station according to an embodiment of the present invention.
8 is an exemplary view showing a PCI collision performance according to an embodiment of the present invention.
9 is an exemplary diagram showing PCI confusion performance according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

In a mobile communication system, a plurality of subscriber terminals and a plurality of micro-base stations simultaneously use the same frequency channel. Therefore, since the use of the same frequency channel causes interference between the concurrent talker and the micro-base station, each micro-base station should appropriately control the transmission power in order to improve the system efficiency and the call quality. In the present invention, the small base station may include a femto base station, a pico base station, a micro base station, an indoor base station, and a relay used for cell expansion. In the drawings of the present invention, a macro base station is described as an example of an outdoor base station, and a femto base station is described as an example of a micro base station.

1 is a block diagram illustrating a configuration of a mobile communication system according to an embodiment of the present invention.

As shown in FIG. 1, the mobile communication system includes, for example, a Global System for Mobile communication (GSM), a 2G mobile communication network such as code division multiple access (CDMA), a long term evolution (LTE) network, a wireless Internet such as WiFi, and a WiBro ( Cellular networks such as Wireless Broadband Internet (WiMax) and World Interoperability for Microwave Access (WiMax) or cellular networks that support packet transmission (e.g., 3G cellular networks such as WCDMA or CDMA2000, High Speed Downlink Packet Access (HSDPA) or High Speed (HSUPA) 3.5G mobile communication network such as Uplink Packet Access, or 4G, etc. to be developed in the future) and macro base station (eNB) 30, femto base stations 21 to 25, and user equipment (UE) 10 It may include any other mobile communication network including, but is not limited to.

As shown in FIG. 1, a mobile communication system may be composed of one or more network cells, and different types of network cells may be mixed in the mobile communication system. The mobile communication system includes a femto base station (Home-eNB) 21 to 25 for managing a narrow range of network cells (femtocells), a macro base station (eNB) 30 for managing a wide range of cells (macrocells), and a user terminal. (UE) 10, a Self Organizing & Optimizing Networks (SON) server 40, and an MME 50. The number of each component shown in FIG. 1 is illustrative, and the number of each component of the mobile communication network in which the present invention can be implemented is not limited to the number shown in the drawings.

The macro base station 30 is a macro base station that can be used in, for example, an LTE network, a WiFi network, a WiBro network, a WiMax network, a WCDMA network, a CDMA network, a UMTS network, But is not limited thereto.

The femto base stations 21 to 25 can be used in a femtocell base station having a radius of, for example, about several tens of meters, which can be used in an LTE network, a WiFi network, a WiBro network, a WiMax network, a WCDMA network, a CDMA network, Features, but are not limited thereto.

The femto base stations 21 to 25 are used for the purpose of solving a shadow area in the cell, and the femto base stations 21 to 25 may be installed in the cell boundary region to improve effective cell coverage expansion and throughput.

The network cell constituting the mobile communication system may include a macro cell and a femtocell. The macrocell may be managed by the macro base station 30, and the femtocell may be managed by the femto base stations 21 to 25. The femto base stations 21 to 25 and the macro base station 30 may each independently have connectivity of the core network.

The user terminal 10 may be a wireless Internet network such as a GSM network and a CDMA network, a wireless Internet network such as an LTE network and a WiFi network, a portable Internet network such as a WiBro network and a WiMax network, But is not limited to, the characteristics of the mobile terminal. In one embodiment, the user terminal 10 may be a macrocell subscriber terminal and / or a femtocell subscriber terminal.

The management server (OAM server) 60, which is a network management device of the base station, is responsible for managing configuration information of the femto base stations 21 to 25 and the macro base station 30. The management server 60 can perform both the functions of the SON server 40 and the MME 50. [

The SON server 40 may include any server that functions to perform macro base station / femto base station installation and optimization and to provide basic parameters or data required for each macro base station / femto base station.

The MME 50 may include any entity used to manage call processing, etc. of the user terminal 10. The MME 50 performs a function of a base station controller (BSC) and can perform resource allocation, call control, handover control, voice and packet processing, and the like to a base station connected thereto.

In one embodiment, one management server 60 may perform the functions of both the SON server 40 and the MME 50, and the SON server 40 and the MME 50 may be one or more macro base stations 30. ) And one or more femto base stations 21 to 25.

In the mobile communication network, a macro cell and a femto cell are assumed to be mixed, but the network cell may be configured only by the macro cell or the femto cell.

In the 3rd generation partnership project (3GPP) long term evolution (LTE), 504 physical cell identity (PCI), which is one of the basic parameters provided by the SON server 40, is configured with 504 and reused by the base station. As an example, if a base station is using PCI # 1, a neighboring base station allocates another PCI except for PCI # 1, and a base station far from a base station using PCI # 1 is used again. do. Since 504 PCIs are divided according to the installation purpose of the base station operator, there is a possibility to reuse the PCI in a more limited range, but the following description assumes that all 504 PCIs can be used.

The macro base station 30 uses an Open Subscriber Group (OSG) for all users to access and sets up PCI within the range of 504, but the femto base stations 21 to 25 installed in the home can use the CSG ( Close Subscriber Group) to ensure that only the owner of the femto base station (21-25) can access it. In addition, since a plurality of femto base stations 21 to 25 having small cell coverage are expected to exist, the PCI range of the base station using the CSG is informed through the "csg-PhysCellIdRange" IE (information element) of the base station broadcast message. That is, some of the 504 PCIs are allocated to the femto base stations 21 to 25 using the CSG. By allocating only limited PCI to the femto base stations 21 to 25 using the CSG, the terminal 10 may increase the handover speed by searching only a portion of the PCI and reduce the power consumption of the terminal 10. The PCI range for the femto base stations 21 to 25 using the CSG is defined in a radio resource control (RRC) broadcast message (3GPP TS36.331), and the ranges that can be set are 4, 8, 12, 16, 24, 32, 48, 64, 84, 96, 128, 168, 252 or 504.

If a base station is installed, whether a base station using OSG or a CSG, the PCI should be set within a predetermined range. In the case of the base station using the OSG, one of 504 PCIs is used, and in the case of the base station using the CSG, one PCI must be satisfied within the range specified by csg-PhysCellIdRange.

1. "collision-free": PCI must be unique within cell coverage.

2. "confusion-free": Peripheral cells must not be assigned the same PCI.

Collision-free means that newly installed base stations and neighboring base stations do not have the same PCI, and confusion-free means that they do not have the same PCI between base stations located near the newly installed base stations. will be.

2 is an exemplary view when a PCI collision occurs according to an embodiment of the present invention, Figure 3 is an exemplary view when a PCI confusion occurs according to an embodiment of the present invention. As shown in FIG. 2, since the same PCI A is allocated to the adjacent base stations, PCI collision occurs. As shown in FIG. 3, since PCI is allocated between the adjacent base stations, there is no PCI collision. PCI confusion occurs because a base station allocated with the same PCI B is located next to both of the centrally located base stations to which is allocated.

When allocating PCI in the range of 504, PCI collision or PCI confusion is less likely.However, if 504 PCI is divided according to the base station operation purpose, the probability of occurrence of PCI collision or PCI confusion increases, and the base station using CSG Selects PCI from a limited range, increasing the likelihood of a PCI conflict or PCI confusion. However, when the PCI range is widened, since the user terminal 10 needs to search for a large number of PCI, the handover speed is slowed and the power consumption of the user terminal 10 is increased. Therefore, the CSG base station uses the PCI within a small range. PCI should be allocated while increasing the reuse rate.

Rather than relying only on cell planning tools, etc. to increase the installation cost, maintenance cost and performance of the wireless network, the base station itself is operating to predict the wireless environment and automatically set necessary parameters. This method of automatically setting parameters required for the base station is called a self organizing network (SON). The SON is divided into basic setup, initial radio configuration, self-optimization, etc. as follows, and is performed with the help of an operation and maintenance (OAM) subsystem as shown in FIG. do.

1. Preferences

IP address configuration,

-Associate with a gateway

-Authentication

2. Initial Wireless Configuration

Physical Cell ID configuration

Neighbor list configuration

-Establish interfaces (eg, X2)

3. Self Optimization

-Optimize neighbor list

-Coverage and capacity optimization

When the basic setting is completed in the mobile communication system, the initial radio parameters are set before the base station is operated. The most basic of the initial radio parameters is the PCI that the cell will use. A simple method for determining the PCI of the base station is to determine any PCI within the PCI range (504 for the OSG, csg-PhysCellIdRange for the CSG). However, if a random PCI is determined without information about the neighboring cell of the base station, the PCI collision and PCI confusion cannot be effectively controlled. To compensate for this, self optimization is performed during the operation of the base station. In order to perform self-optimization, the base station receives handover information from the connected user terminal 10 and exchanges information such as PCI or neighbor cell list (NCL) between cells determined to have a problem. Resolve the confusion problem. However, this solution is performed in the process of performing the handover by the user terminal 10 during the base station operation, it takes a lot of time for the base station to operate stably without PCI conflict and PCI confusion. To compensate for this, the received PCI can be measured and based on this, the base station can set the PCI and NCL.

5 is an exemplary view showing the configuration of a PCI automatic allocation system according to an embodiment of the present invention.

As shown in FIG. 5, the PCI automatic allocation system 100 includes an information collector 110 for collecting information necessary for PCI allocation and NCL configuration, and a PCI of a base station using at least one of different PCI determination methods. Whether the PCI allocator 120 for allocating the NCL configuration unit 130 and the NCL configured with the assigned PCI in association with the PCI determination method of the PCI allocator 120 are set without collision or confusion. PCI determining unit 140 to determine the.

The information collecting unit 110 collects PCI information allocated to the neighboring cells and estimates CGI when collecting or not directly collecting cell global identity (CGI) information in order to know an independent identifier of the neighboring cell. In addition, the information collecting unit 110 collects the NCL broadcasted by the cell when the CGI of the neighboring cell is determined. Although the apparatus and method for collecting PCI, CGI, and NCL are not defined in the present embodiment, when the base station includes a sniffer (downlink receiving apparatus for the base station to measure neighboring cells), cell discovery is performed using a sniffer. To detect PCI and receive broadcast messages to obtain CGI and NCL. As a device performing a function similar to a sniffer of a base station, since the user terminal 10 includes a downlink receiver, the sniffer may be replaced through a measurement function of the user terminal 10 connected to the cell. Even if a sniffer is used or a terminal connected to a cell can be assisted by the OAM server 60 and each base station stored in the OAM server 60 when the base station includes a global positioning system (GPS) reception function. By using the position information and the position information measured by the GPS can obtain information such as PCI, CGI, NCL of the neighboring cell adjacent to the newly installed base station.

Even if the base station includes a sniffer, the PCI information that can be known from the physical layer can be detected, but if the CGI information cannot be received by receiving the RRC broadcast message, the location is estimated using the detected PCI information. The CGI information may be obtained or the approximate location may be estimated through an IP address, and the CGI information may be obtained. In order to estimate the CGI after the position estimation using the PCI information, one of the detected PCIs is selected to be highly related. The closer the transmitter and the receiver are located, the higher the reception power. Therefore, the method of determining the degree of relevance may select the largest reception power for the PCI. When one PCI is selected, the next most relevant PCI is determined to calculate the physical distance or network connection distance for each selected PCI. The physical distance represents the distance by the coordinates on the map, and the network connection distance represents the shortest hopping number for reaching from one base station to another base station. A method of calculating the network connection distance will be described later. Calculating the physical distance or network connection distance for a selected PCI can result in multiple combinations because there are several base stations using the same PCI on the network. Two or more PCI information can be used to increase the accuracy of the estimated location. Finally, the CGI information of the neighbor cell is obtained based on the estimated position.

The PCI allocator 120 allocates PCI using at least one of a received power based PCI determination method, a network connection based PCI determination method, and a statistics based PCI determination method according to the information received from the information collecting unit 110. .

In order to use the received power-based PCI determination method, the PCI allocator 120 receives information about PCI allocated to neighboring cells and received power information for each cell from the information collector 110. In the present invention, the received power information is a value associated with or calculated through the received power, such as received signal strength indicator (RSSI), reference signal received power (RSRP), reference signal received quality (RSRQ), synchronization signal received power, and the like. Means. When the PCI allocation unit 120 receives the PCI used by the neighboring cells and the reception power information for each cell, the PCI allocation unit 120 allocates the PCI having the smallest reception power as shown in Equation 1.

는

가 할당된 기지국으로부터 수신되는 수신 전력을 나타낸다. 만약 동일 PCI에 대하여 두 개 이상의 값이 수신되면 수신된 값들 중 최대값을 이용한다.In Equation 1,

The

Denotes the received power received from the assigned base station. If more than one value is received for the same PCI, the maximum of the received values is used.

When calculating the path loss instead of the received power, the PCI with the largest path loss is allocated as shown in Equation 2.

는

가 할당된 기지국으로부터의 경로감쇄를 의미한다. 만약 동일 PCI에 대하여 두 개 이상의 값이 계산되면 계산된 값들 중 최소값을 이용한다.In Equation 2,

The

Means path attenuation from the allocated base station. If two or more values are calculated for the same PCI, the minimum of the calculated values is used.

The PCI allocator 120 allocates the PCI by the statistical-based PCI determination method when the PCI received from the information collection unit 110 is smaller than the range of the PCI that can be set. In one embodiment, the PCI allocation unit 120 selects one of 6 and 7 according to the statistics-based PCI determination method when the range of PCI that can be set is 0-7 but the received PCI is 0-5.

In order to use a network connection-based PCI determination method, the PCI allocator 120 receives PCI and CGI allocated to the neighbor cells from the information collector 110 and NCL information of the neighbor cells. The PCI allocator 120 calculates a network connection distance through the received PCI, CGI, and NCL. The network connection distance means the shortest hopping number for reaching from one base station to the next. As an example, as shown in FIG. 6, assuming that a network is configured and a connection state with a neighboring cell is determined, when attempting to allocate PCI of Cell X, the network connection distance between Cell X and Cell F is Cell X → Cell A. → Cell E → Cell F or Cell X → Cell B → Cell E → Cell F. There are many known algorithms that can detect such network connection distances. In one embodiment, a network connection distance may be calculated using a breadth-first search (BFS) algorithm. When the network connection distance is calculated, the PCI with the largest network connection distance is allocated as shown in Equation 3. When receiving more PCI than the predetermined threshold from the information collecting unit 110 may be assisted by the received power-based PCI determination method. That is, the PCI allocator 120 calculates a network connection distance with respect to PCI having PCI or a predetermined level or more by the received power for each PCI received from the information collector 110.

는 PCI를 설정하고자 하는 셀로부터

를 갖는 셀까지의 최단 네트워크 연결거리를 나타낸다.In equation (3)

Is the cell from which you want to configure PCI.

It shows the shortest network connection distance to the cell with.

If the PCI obtained by the network search is smaller than the range of the settable PCI, the PCI is allocated by the statistics-based PCI determination method.

In order to use the statistics-based PCI determination method, the PCI allocation unit 120 receives the location information from the information collecting unit 110. If you want to use the statistics-based PCI determination method for a narrow area such as an office, the location information may not be needed, and the statistics-based PCI determination method may be implemented through the IP-level location information. Once the location information is acquired, the minimum number of PCI overlaps being used for the specific area around it is measured and the minimum used PCI is allocated. As an example, if the range of available PCI is 0 to 3 and PCI 0 is used twice, PCI 1 is used 3 times, PCI 2 is used 4 times, and PCI 3 is used 0 times, the PCI allocator 120 is the smallest. Allocate PCI 3 used for recall. On the other hand, if the PCI usage can not be measured, it can be set to allocate the next PCI after the recently allocated PCI, and if the PCI usage cannot be measured and there is no recently allocated PCI information, the range to which the PCI can be allocated You can also set to assign an arbitrary PCI to the.

The NCL configuration unit 130 uses the reception power-based NCL configuration method when the PCI allocation unit 120 uses the reception power-based PCI determination method in conjunction with the PCI determination method used by the PCI allocation unit 120. If the allocation unit 120 uses the network connection based PCI determination method, the network connection based NCL configuration method is used. If the PCI allocation unit 120 uses the statistics based PCI determination method, the location based NCL determination method is used. Set the NCL.

In the reception power based NCL configuration method, the NCL configuration unit 130 may set the NCL using a subset of the neighbor cell PCI or the neighbor cell PCI used in the reception power based PCI determination method.

In the network connection-based NCL configuration method, the NCL consists of a PCI combination of cells whose network connection distance falls below a predetermined threshold. For reference, when the network connection distance is set to a value less than or equal to 1, the NCL may be set similarly to the reception power-based NCL configuration method.

In the location-based NCL configuration method, the NCL configuration unit 130 configures the PCI around the estimated location as the NCL. However, in the location-based NCL configuration method, the area for measuring PCI duplicate count and the area for NCL configuration may be different.

The PCI determining unit 140 determines whether there are two determination criteria described above, that is, PCI collision or PCI confusion, and if there is no problem, the PCI determining unit 140 sets the PCI and NCL configuration unit 130 selected by the PCI allocating unit 120. Maintain the NCL. The PCI determining unit 140 resets other PCI and NCL when a PCI collision or a PCI confusion problem occurs. If resetting the PCI and NCL in a newly installed cell does not solve the problem, it may be set to change the PCI and NCL of other cells.

The present invention is configured by the information collecting unit 110, PCI allocating unit 120, NCL configuration unit 130 and PCI determination unit 140 to automatically set the PCI and NCL of the newly installed base station. The PCI allocator 120 operates using at least one of the PCI determining methods according to the information provided by the information collecting unit 110. An embodiment is described below with reference to FIG. 6.

When Cell X is newly installed and automatically sets up PCI and NCL based on the received power, the received power for each cell must be measured and listed by the magnitude of the received power. In this embodiment, since Cell A and Cell H have the same PCI, the value of Cell A with a larger reception power is used. Assuming that the received power is as follows, Cell X has the smallest received power.

Cell A> Cell B> Cell C> Cell E> Cell D> Cell F> Cell G> Cell I

NCL, which is configured based on the received power, consists of PCI 0 ~ 2 of Cell A ~ C with the highest received power.

If Cell X is newly installed and automatically sets up PCI and NCL based on the network connection, you must calculate the network connection distance for each cell. As an example, when Cell A, Cell B and Cell C are found, the shortest network connection distance is as follows. Since Cell A and Cell H use the same PCI, Cell A with the minimum network connection distance is used.

Network connection distance 1: Cell A (PCI 0), Cell B (PCI 1), Cell C (PCI 2)

Network connection distance 2: Cell D (PCI 3), Cell E (PCI 4), Cell G (PCI 6)

Network connection distance 3: Cell F (PCI 5)

Network connection distance 4: Cell I (PCI 7)

As mentioned above, PCI No. 7 assigned to Cell I has the largest network connection distance, so PCI of Cell X is assigned to No. 7 and NCL is network It consists of PCI 0 ~ 2 of Cell A ~ C with the smallest connection distance.

If Cell X is newly installed and automatically sets up PCI and NCL based on the statistics, you will need to get PCI statistics for that particular area. In one embodiment, if the statistics for the cell A ~ H excluding Cell I is obtained, PCI 0 is used twice and PCI 1-6 are used once. Since PCI 7 is used 0 times, PCI of Cell X becomes 7 and NCL consists of PCI 0 ~ 2 of Cell A ~ C located in close proximity.

In order to know the effects of the present invention, a simulation environment was constructed as follows.

-Femto base station transmit power: 10dBm

-Femto base station installation type: 5 by 5 grid model

Antenna gain: 0 dBi

Noise Density: -174dBm / Hz

Interference Noise Density: -110dBm / RB

Noise figure: 5dB

Macro base station transmit power: 46dBm

Path Loss for Macro Cells: 100dB (Cell site), 140dB (Cell edge)

The femto base station used a 5 by 5 grid model as shown in FIG. 7. The 5 by 5 grid model is an installation model for evaluating femto base stations in 3GPP. There are 5 base stations in 10m intervals and 25 base stations in total. The 25 base stations were simulated in two cases, a cell site located close to the macro cell and a cell edge located far from the macro cell.

8 and 9 illustrate PCI collision performance and PCI confusion performance according to each PCI determination method. The random PCI configuration method is very poor in performance, but there are many improvements that can be made with the statistics-based PCI decision method. The method of determining PCI based on received power and the method of determining PCI based on statistics have different performances depending on the cell site and cell edge.In the case of small interference from the cell, the received power based PCI and network connection based PCI are determined. Although the performance of the method is slightly different, it converges in a similar range, but when the interference from the macro cell is large (Cell site), the PCI that can be received decreases due to the macro interference, which causes a significant performance degradation.

While the above methods have been described through specific embodiments, the methods may also be implemented as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

Although the present invention has been described in connection with some embodiments thereof, it should be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention as understood by those skilled in the art. something to do. It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

10: user terminal 21 ~ 25: femto base station
30: macro base station 40: SON server
50: MME 60: Management Server (OAM Server)

Claims (17)

PCI (Physical Cell Identity) automatic allocation system,
An information collector configured to collect information necessary for PCI allocation and neighbor cell list (NCL) configuration;
A PCI allocator configured to determine PCI using at least one PCI determination method; And
And an NCL component configured to set the neighbor cell list in association with a PCI determination method used by the PCI allocator. The method of claim 1,
The PCI automatic allocation system further comprises a PCI determination unit for determining whether the PCI determined by the PCI allocation unit and the PCI collision and PCI confusion of the neighbor cell list set by the NCL configuration unit. The method of claim 2,
The PCI determining unit,
If the PCI collision and PCI confusion occurs, the PCI and the neighbor cell list is reconfigured, and if the PCI collision and PCI confusion is not resolved even through the reconfiguration of the PCI and the neighbor cell list, the PCI and neighbor cell list of other base stations To reset, PCI auto allocation system. The method of claim 1,
The information collecting unit,
PCI information set in the neighboring cell of the base station, reception power for each PCI, CGI and neighboring cell list set in the neighboring cell of the base station, and the neighboring information as information necessary for the PCI allocation and the neighbor cell list configuration; PCI automatic allocation system for collecting location information of a base station that governs a cell. 5. The method of claim 4,
The location information may include:
A method for estimating an approximate location through an IP address, a method for estimating a location through an apparatus for indicating a location, and a base station that manages the neighbor cell by calculating a physical distance or a network connection distance using the PCI information. Estimating using at least one of the methods of estimating the installed location. The method of claim 1,
The information collecting unit,
And at least one of a sniffer or downlink receiver, a user equipment, an operation and maintenance (OAM) server, and a global positioning system (GPS) installed in the base station. The method of claim 1,
The PCI determination method,
A PCI automatic allocation system comprising a received power based PCI determination method, a network connection based PCI determination method and a statistics based PCI determination method. The method of claim 7, wherein
The received power based PCI determination method,
Received signal strength indicator (RSSI), reference signal received power (RSRP), reference signal received quality (RSRQ), synchronization signal received power, or the received power for PCI and the neighboring cell allocated from the information collecting unit The PCI automatic allocation system for receiving the received power information including at least one of the values calculated through the to select the PCI with the lowest received power. The method of claim 7, wherein
The received power based PCI determination method,
If path attenuation is calculated for each PCI, then the PCI auto-allocation system selects the PCI with the largest path attenuation. The method of claim 7, wherein
The PCI allocation unit,
If the PCI collected by the information collecting unit is smaller than the range of the settable PCI, PCI except for the collected PCI to determine the PCI using the statistics-based PCI determination method, PCI automatic allocation system. The method of claim 7, wherein
The network connection based PCI determination method,
And a PCI, CGI and neighbor cell list allocated to the neighboring cell from the information collecting unit to calculate a network connection distance to select a PCI having the longest network connection distance. The method of claim 11,
The network connection distance is,
PCI automatic allocation system that represents the shortest hopping number for reaching from one base station to another. The method of claim 7, wherein
The PCI allocation unit,
The PCI automatic allocation system in the statistics-based PCI determination method to determine the PCI having the minimum number of times by receiving the position information from the information collecting unit by measuring the number of times of PCI use. PCI (Physical Cell Identity) automatic allocation method,
Collecting information necessary for PCI allocation and neighbor cell list (NCL) configuration;
Determining PCI of the base station using at least one PCI determination method; And
And setting the neighbor cell list in association with the at least one PCI determination method. 15. The method of claim 14,
And determining whether the determined PCI and the PCI neighbor and PCI confusion of the set neighbor cell list are determined. 16. The method of claim 15,
Determining whether the PCI conflict and PCI confusion,
Reconfigure the PCI and the neighbor cell list when the PCI collision and PCI confusion occurs, and if the PCI collision and the PCI confusion are not resolved by the reconfiguration of the PCI and the neighbor cell list PCI reassignment method. 15. The method of claim 14,
The PCI determination method,
PCI automatic allocation method, including a received power based PCI determination method, a network connection based PCI determination method and a statistics based PCI determination method.

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