KR20100046492A - Method for processing hand-over used inter rat and mobile communication terminal for use therein - Google Patents

Abstract

PURPOSE: A mobile terminal and a method for processing hand over using inter rat are provided to utilize inter RAT(Radio Access Technologies) neighbor list as neighbor list for femto cell, thereby performing inter-cell reselection and hand over process. CONSTITUTION: A mobile communication terminal receives broadcasting information(S10). The mobile communication terminal confirms inter RAT(Radio Access Technologies) list(S20). If the inter RAT list is defined, the mobile communication terminal inquires inter RAT cell information list(S30,S40). The mobile communication extracts neighbor list information among information items of broadcasting information(S50). The mobile communication terminal performs a hand over processing(S60).

Description

Method for processing hand-over used inter RAT and mobile communication terminal for use therein {Method for processing hand-over used inter RAT and mobile communication terminal for use therein}

The present invention relates to an inter-cell handover and cell reselection processing procedure in a mobile communication system, and more particularly, to an efficient inter-cell handover and cell reselection processing method in a mobile communication environment in which a public network cell and a femto cell are mixed. will be.

Recently, femto cell technology for providing mobile communication services to areas much smaller than the existing mobile communication radius has been actively studied. A femto cell is a technology that provides mobile communication services through a femto access point (AP) connected to a general-purpose Internet circuit in an area where shadows of a macro cell are degraded, such as a home or a building. The femto cell is also used for the purpose of ensuring the quality of mobile communication services, and can also be used as a means of providing low rates through femtozone services. In addition, since femtocells use a universal Internet line for connection to the core network, the installation cost and maintenance cost are low, and the mobile network can be installed anywhere where the Internet line is installed. There is this.

Such femtocells are also referred to as ubicells, microcells, etc., and are generally included or overlapped in the macrocell region of the mobile communication network. The femtocell performs a cell selection procedure or a handover procedure similarly to a macrocell. That is, when the mobile terminal enters the femtocell, it can be provided with the femtocell service only by accessing the base station that manages the femtocell. Therefore, when the femtocell subscriber enters the femtocell region, the femtocell subscriber may disconnect from the macrocell base station and access the femtocell base station.

In the mobile communication system, a cell selection / reselection or handover procedure is performed between macro cells or between macro cells and femtocells as described above. In this case, the mobile communication system includes the neighbor list of cells in the broadcast information and provides the mobile communication terminal. The terminal performs handover and reselection processing on the cells included in the neighbor list.

As described above, a handover / reselection method from a macro (public network) cell to a femtocell is mostly applicable only in an environment in which a radio network boundary between a public network cell and a femtocell is clear. In other words, the use of such a conventional method in a region where radio waves overlap in reality is difficult in reality.

However, most of femtocells are currently used for securing capacity or securing in-building coverage in a traffic-intensive area. Therefore, there is a high possibility that a large number of femtocells exist in a public network cell, and in the case of a traffic dense area, a large number of neighbor lists are included among most public network cells.

In other words, the femtocell commercial network is likely to be used in the metropolitan area because it is used for traffic distribution in the traffic dense area or securing coverage for the inbuilding call impossible area. In this case, an environment using multiple femtocells in one public network cell will be configured. In particular, since most of the neighbor network neighbor list is already used in the region of such an environment, there is a problem that a situation in which there is no room for allocation for femtocells occurs.

The present invention has been made to solve such a problem, and a method and apparatus for performing inter-cell reselection and handover processing by using a separate neighbor list capable of allocating a femtocell in addition to the existing neighbor network neighbor list. The purpose is to provide.

Other objects and advantages of the invention will be described below and will be appreciated by the practice of the invention. Further, objects and advantages of the present invention can be realized by the means and the combination shown in the appended claims.

In order to achieve the above object, the handover processing method using the inter-RAT according to the present invention is a method for inter-cell handover or cell reselection using neighbor list information included in broadcast information in a mobile communication system. a) receiving broadcast information through a base station from a mobile communication system; (b) checking whether an inter-RAT list is defined in the received broadcast information; (c) extracting neighbor list information by querying the inter RAT cell information list when the inter RAT list is not defined; And (d) performing inter-cell handover or cell reselection processing using the extracted neighbor list information.

According to another aspect of the present invention, a mobile communication terminal performing inter-cell handover or cell reselection processing using neighbor list information included in broadcast information in a mobile communication system, and receives broadcast information from a mobile communication system through a base station. Communication means; Checking whether the inter-RAT list is defined in the broadcast information received from the communication means; and if the inter-RAT list is not defined, searching for the inter-RAT cell information list from the broadcast information to extract neighbor list information Neighbor list extracting means; And handover processing means for performing inter-cell handover or cell reselection processing by using the neighbor list information extracted by the neighbor list extracting means.

According to the present invention, a mobile communication system registers a neighbor list for a femtocell by using an inter-RAT neighbor list as a neighbor list for a femtocell, regardless of the capacity of the public network neighbor list used in the existing network, and uses the same to reselect and inter-cell between cells. Provides the effect of performing the treatment.

In addition, by using the inter-RAT neighbor list in addition to the public network neighbor list for the femtocell, it provides an effect that can overcome the limitation of the lack of the number of neighbor list registration occurs in the existing cell density area.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a diagram schematically illustrating a network configuration of a mobile communication system including a femto cell in which a handover processing method using inter RAT is implemented according to an embodiment of the present invention.

Referring to FIG. 1, a mobile communication system includes a femto cell 120, a macro cell 130, and a core network 150.

The macro cell 130 is a conventional radio access cell of a mobile communication system and includes a base station (Node-B) that manages radio resources and a base station controller (RNC) that controls the base station. Provides a mobile communication service by performing a wireless communication with.

The femto cell 120 is mainly for the purpose of guaranteeing the quality of mobile communication service in the area where the radio wave of the macro cell 130 is degraded, such as a home or a building, or a low cost such as a femto zone service. As a radio access cell utilized for the purpose of doing so, a femto base station 113 (Femto AP) connected with a universal Internet line (IP network) is used. The mobile terminal 110-1 entering the femto cell 120 is connected to the femto base station 113 and is connected to the core network 150 through the femto base station 113 through a universal Internet line.

The core network 150 is a network of a mobile communication system for providing a data service and a voice service. The core network 150 is connected to the macro cell 130 through an exchanger (MSC) or a packet switched node (SGSN), and the femtocell ( 120 is connected through an IP network and a gateway GW to provide a communication service to the mobile terminal 110 in the macro cell 130 or the femto cell 120.

When the mobile communication terminal 110 moves from the macro cell 130 to the femto cell 120 region, the connection is switched from the macro cell base station to the femto base station 113 through a handover or cell reselection procedure. In this case, the mobile communication terminal 110 receives broadcast information from the system and performs a handover or cell reselection procedure using a neighbor list of cells included in the broadcast information. Here, the system includes the neighbor list for the public network cells and the neighbor list for the femtocells together in the broadcast information broadcast through the base station.

Specifically, the neighbor list information on the cells of the public network is the same as the existing standard, the Inter Frequency neighbor list or the Intra Frequency neighbor of the broadcast information (for example, the System Information Block (SIB) message of the WCDMA standard) Include in items such as lists. In addition, neighbor list information on femtocells is included in an information element of an Inter RAT Cell Info List of SIB # 11 in the case of the WCDMA standard. In this case, the inter-RAT function (handover / reselection to another communication network) is not used. Currently, there is no handover between RATs in Korea. Therefore, in an environment where an inter-RAT handover is not used as in Korea, the inter-RAT neighbor list can be used as a femtocell neighbor in a SIB of a WCDMA standard.

Of course, when the inter-RAT function is used, the inter-RAT related neighbor list information is included in the corresponding information item, and the inter-RAT list, which is information that the inter-RAT function is used in the RAT item of broadcast information SIB # 3, is defined.

2 is a diagram illustrating a configuration of a mobile communication terminal device supporting handover processing using inter RAT according to an embodiment of the present invention.

2, the mobile communication terminal 110 according to the present invention includes a communication module 112, a broadcast information analyzer 115, a neighbor list extractor 116, and a handover processor 117. Control module 114 and the like.

The communication module 112 communicates with a base station (a base station of a macro cell or a femtocell) of a mobile communication system to transmit and receive various signals. In particular, it receives a broadcast information message from a base station through the system. The broadcast information message may be an SIB message according to the WCDMA standard.

The control module 114 controls the overall operation of the mobile communication terminal, analyzes various signals received through the communication module 112, and performs control processing accordingly. The control module 114 includes a broadcast information analyzer 115, a neighbor list extractor 116, a handover processor 117, and the like.

The broadcast information analyzer 115 analyzes the broadcast information message received through the communication module 112. That is, the broadcast information message is analyzed to determine whether an inter RAT list is defined. Whether the inter RAT list is defined can be checked by referring to the RAT item of SIB # 3, for example, of the WCDMA standard. The broadcast information analyzer 115 determines an inter RAT mode when defined according to whether to define an inter RAT list, and determines a femtocell mode when not defined.

3 is a diagram illustrating an example of parameters included in system information block type 3 (SIB # 3) according to the WCDMA standard.

As shown in FIG. 3, the RAT list item may be referred to to determine whether an inter RAT list is defined. If an inter-RAT list is defined, it supports inter-RAT handover function. If not defined, it means that the system does not support inter-RAT handover function. Currently, domestic RAT list is not defined because it does not support handover function between different mobile communication networks.

The neighbor list extractor 116 extracts neighbor list information from a broadcast information message for a handover and cell reselection processing procedure. The neighbor list extractor 116 extracts public network cell neighbor list information from a broadcast information message, and when the broadcast information analyzer 115 determines that the inter RAT list is not defined, the inter RAT cell information list Inter RAT Cell Info List) is searched to extract additional Naver List information set here. That is, when the existing public network cell neighbor list is extracted and the inter RAT is not defined, the neighbor list is additionally extracted from the interRAT cell information list and used as a femtocell neighbor. As an example of the WCDMA standard, the inter RAT cell information list is included in the information item of SIB # 11.

4 is a diagram illustrating an example of a parameter included in a system information block type 11 (SIB # 11) according to the WCDMA standard. 5 is a diagram illustrating an example of each parameter item in SIB # 11.

As shown in FIG. 4 and FIG. 5, neighbor list information of a femtocell is included in a measurement control system information item of an SIB # 11 message. In this item, an inter RAT measurement system information parameter exists as shown in Fig. 5A, and an inter RAT cell information list information item is stored in this parameter as shown in Fig. 4B. In addition, the public network cell neighbor list information is stored in the intra frequency cell information list and the inter frequency cell information list defined in SIB # 11.

The handover processing unit 117 performs a handover processing procedure in association with a mobile communication system targeting cells included in the neighbor list information extracted by the neighbor list extracting unit 116. That is, the signal strength of the cells included in the neighbor list is measured and the measurement report message is transmitted to the system, and handover or cell reselection processing is performed to the target cell according to the system's instruction. In this case, the cells measuring the signal strength are included in the neighbor list, and targets both the public network cell neighbor list and the femtocell neighbor list. In addition, the handover process or the cell reselection process as described above are all performed in the idle mode or the traffic mode of the mobile communication terminal.

6 is a flowchart illustrating a procedure of a handover processing method using inter RAT according to an embodiment of the present invention.

In this embodiment, the procedure according to the WCDMA standard will be described.

First, the mobile terminal performs a procedure for receiving broadcast information broadcast through the base station from the system. In this case, the received broadcast information includes an SIB message (S10).

After receiving the broadcast information, the terminal analyzes the broadcast information and checks the inter RAT list. At this time, the subject of analysis is a SIB # 3 message and refers to the RAT list information item in SIB # 3.

Next, a procedure of analyzing and confirming broadcast information to determine whether an inter RAT list is defined is performed. At this time, it is also determined whether the inter-RAT list is defined in the RAT list information item in SIB # 3 (S30).

As a result, when the inter RAT list is not defined, it is determined that the inter RAT cell information list information item included in the broadcast information is used as the neighbor list information for the femtocell. Accordingly, a procedure of inquiring the inter RAT cell information list included in the broadcast information is performed. The inter RAT cell information list is included in SIB # 11 (S40).

After retrieving the information item including Naver List information from the broadcast information, the procedure of extracting the Naver List information contained in the corresponding item is performed. At this time, a procedure for extracting the neighbor list for the femtocell included in the inter-RAT cell information list queried in step S40 and the neighbor list for a general public cell is performed. Here, the neighbor list for the public network cell extracts the inter frequency neighbor list and the intra frequency neighbor list from the inter frequency cell information list and the intra frequency cell information list (S50).

When the neighbor list included in the broadcast information is extracted by the mobile communication terminal, handover or cell reselection processing is performed by interworking with the mobile communication system using the extracted neighbor list.

Specifically, in the mobile communication terminal, the signal strength is measured for cells included in the extracted neighbor list, that is, the neighbor list for the public network cell and the neighbor list for the femtocell (the neighbor list extracted from the inter RAT cell information list when the inter RAT is not defined). do. After measuring the signal strength, the terminal transmits the measured value as a measurement report message to the mobile communication system.

The system receives a measurement report message, and proceeds to select a target cell for handover or cell reselection in neighboring cells (cells included in the neighbor) of the terminal. At this time, the target cell is selected based on the signal strength of each cell measured by the terminal. That is, the cell having the largest signal strength among the cells included in the neighbor list is selected as the target cell, and an instruction message for handover or cell reselection to the corresponding cell is transmitted to the mobile communication terminal.

In addition, in the present embodiment, in order to occupy (select) the femtocell first when the radio network signal strengths of the public network cell and the femtocell are similar, the radio network signal strength of the femtocell is higher than the specific threshold value set in the network. Predominantly occupy femtocells.

In addition, in the present exemplary embodiment, only the signal strength is measured in the mobile communication terminal and the target cell is selected in the system side. However, the present invention is not limited thereto. It goes without saying that all the processes for selecting the target cell for the over or cell reselection process may be performed (S60).

As described above, when the inter-RAT cell information list information item is used as a femtocell naver, for example, 32 femtocells can be added as a naver in one public network cell.

On the other hand, if the inter-RAT list is defined in the broadcast information message as a result of the determination in step S30, the handover and cell reselection processing is performed in accordance with the conventional inter-RAT function according to the existing standard. Since this procedure is known in the existing standard, detailed description of the procedure according to the existing standard will be omitted. (S35)

The embodiment described above shows a processing procedure performed when the mobile communication terminal is in the standby mode.

In another embodiment, an example of a processing procedure performed when the mobile communication terminal is in a call mode will be briefly described.

When the mobile communication terminal is in a call mode, that is, in a traffic state, the handover or cell reselection procedure first transmits updated neighbor list information from a RNC (base station controller) to a terminal through a measurement control (MC) message. When a terminal in a traffic state performs a handover from a public network cell to a femtocell, the network transmits a neighbor list for the femtocell to the terminal using the information item "Inter_RAT Cell Info List" in the MC message. The frequency information of the femtocell to be handed over utilizes a frequency information input related information item of the inter-RAT cell information list in the MC message.

At this time, the target of the RAT can be selected by selecting from the GSM or IS-2000, the GSM can be defined through the ARFCN value, the IS-2000 can be defined through the frequency information item in the System Specific Measurement Info. Since the frequency notation on the standard between GSM, IS-2000, and WCDMA is different from each other, it is required to separately process the terminal and the network in advance.

In addition, when the frequency of the current terminal in the public network cell (Camping) and the frequency of the femtocell is the same, the terminal does not operate the compressed mode (Compressed Mode) even though the inter-RAT neighbor list, the general intra-frequency hard handover procedure According to the handover process. On the other hand, if the frequency is different, the handover process is performed according to the inter-frequency hard handover procedure following the compression mode.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical spirit of the present invention, the present invention includes matters described in such drawings. It should not be construed as limited to.

1 is a diagram schematically illustrating a network configuration of a mobile communication system including a femto cell in which a handover processing method using inter RAT is implemented according to an embodiment of the present invention.

2 is a diagram illustrating a configuration of a mobile communication terminal device supporting handover processing using inter RAT according to an embodiment of the present invention.

3 is a diagram illustrating an example of parameters included in system information block type 3 (SIB # 3) according to the WCDMA standard.

4 is a diagram illustrating an example of a parameter included in a system information block type 11 (SIB # 11) according to the WCDMA standard.

5 is a diagram illustrating an example of each parameter item in SIB # 11.

6 is a flowchart illustrating a procedure of a handover processing method using inter RAT according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: mobile communication terminal 120: femtocell

130: macro cell 150: core network

Claims (14)

A method for processing inter-cell handover or cell reselection using neighbor list information included in broadcast information in a mobile communication system, (a) receiving broadcast information from a mobile communication system through a base station; (b) checking whether an inter-RAT list is defined in the received broadcast information; (c) extracting neighbor list information by querying the inter RAT cell information list when the inter RAT list is not defined; And (d) performing inter-cell handover or cell reselection processing using the extracted neighbor list information; and a handover processing method using inter RAT. The method of claim 1, Step (d) is, A method for handover processing using inter-RAT, characterized in that for performing inter-cell handover or cell reselection by measuring signal strength on extracted neighbor list information and public network cell neighbor list information. The method according to claim 1 or 2, The neighbor list extracted from the inter RAT cell information list is a neighbor list of a femto cell. The method of claim 2, The public network cell neighbor list information includes an inter frequency neighbor list and an intra frequency neighbor list included in broadcast information. The method according to claim 1 or 2, The mobile communication system is a handover processing method using the inter-RAT, characterized in that the WCDMA system is a mixture of the public network cell and femtocell. The method according to claim 1 or 2, The broadcast information is a handover processing method using an inter RAT, characterized in that the system information block (SIB) message according to the WCDMA standard. The method of claim 6, In step (b), it is checked whether the inter RAT list is defined in a message SIB # 3 (System Information Block Type 3), In the step (c), the inter-RAT cell information list queries the System Information Block Type 11 (SIB # 11) message. The method according to claim 1 or 2, Step (d) is, In the handover or reselection processing, when the radio network signal strength of a cell included in the neighbor list extracted from the inter RAT cell information list is greater than or equal to a threshold, the hand using the inter RAT, characterized in that the weighting process takes precedence over the public network cell. Over handling method. The method according to claim 1 or 2, The handover or reselection processing is a handover processing method using an inter RAT, characterized in that applied to both the idle (Idle) mode and traffic mode of the terminal. A mobile communication terminal performing inter-cell handover or cell reselection processing using neighbor list information included in broadcast information in a mobile communication system, Communication means for receiving broadcast information from a mobile communication system through a base station; Checking whether the inter-RAT list is defined in the broadcast information received by the communication means; and if the inter-RAT list is not defined, searching for the inter-RAT cell information list from the broadcast information to extract neighbor list information Neighbor list extracting means; And And handover processing means for performing inter-cell handover or cell reselection using the neighbor list information extracted by the neighbor list extracting means. The method of claim 10, The neighbor list extracting means, And extracting an inter-frequency neighbor list and an intra-frequency neighbor list, which are public network cell neighbor list information, from the broadcast information. The method of claim 10 or 11, The handover processing means, A mobile communication terminal device comprising: measuring signal strength with respect to neighbor list information and public network cell neighbor list information extracted from an inter-RAT cell information list, and performing inter-cell handover or cell reselection processing in association with a mobile communication system; The method of claim 10 or 11, The neighbor list extracting means, wherein the neighbor list extracted from the inter RAT cell information list is a neighbor list of a femto cell. The method of claim 10 or 11, The handover processing means, A mobile communication terminal device, characterized in that performed in both the idle mode and the traffic mode state of the terminal.

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