KR101001045B1 - Frequency Transition Method and System for Inducing Connection of Mobile Terminals Inaccessible to Femtocell to Macrocell in Femtocell Service Environment - Google Patents

Abstract

The present invention relates to a frequency shifting method and a system therefor for inducing a mobile terminal inaccessible to a femtocell in a femtocell service environment to a macrocell, and a system for the same. A frequency shifting method for inducing a connection to a macrocell includes: receiving a femtocell connection request message from a mobile station; Determining whether the mobile terminal is accessible to the femtocell; Extracting a macrocell frequency accessible by the mobile terminal when it is impossible to connect; And shifting the access frequency of the mobile terminal to the extracted macro cell frequency. According to the present invention, a mobile terminal that cannot be connected to a femtocell is connected to a macrocell, thereby minimizing service white space of the mobile terminal caused by retrying unnecessary connection to the femtocell.

Femtocell, macrocell, neighbor list, femtocell frequency, macrocell frequency, frequency shift

Description

Frequency shift method and system for inducing access to mobile terminal inaccessible to femtocell to femtocell in femtocell service environment and system for the same

The present invention relates to a femtocell technology in a mobile communication system, and more particularly, to a frequency shifting method for inducing a connection to a macrocell and a system therefor when a mobile terminal attempting to access a femtocell cannot be connected to the femtocell. will be.

As the mobile terminal and the mobile communication system are developed day by day, securities services, wireless Internet services, location tracking services, etc. are provided to subscribers. In addition, mobile operators continue to research to provide faster, cheaper and more diverse services than current services.

One of the research subjects is a femtocell service that further subdivides a cell, which is a service area of a mobile communication system, and connects a mobile terminal located in the cell area to a broadband internet network. A femtocell is a compound word of femto, which means one hundredth of a trillion, and a cell, which is a service area unit of a mobile terminal, and is much smaller than a conventional mobile communication radius through a femtocell access point (AP). It is a technology that provides a mobile communication service for a region. Femtocells are also used to guarantee the quality of mobile communication services in areas where shadows of the macro cell are degraded, such as homes or buildings, or in shadowed areas, and provide low rates through femtozone services. It can also be used as a means. In addition, since femtocells use a universal Internet line for connection to the mobile communication core network, the installation cost and maintenance cost are low, and the mobility is also excellent because it can be installed anywhere in the area where the Internet line is installed. There is this.

However, femtocell APs (Access Points), which are small base stations of femtocells, have a small coverage, thus limiting the number of subscribers (typically four) that can be accommodated simultaneously. Accordingly, the femtocell AP provides femtocell services only to subscribers with access rights and blocks the access of unauthorized subscribers. In addition, the femtocell AP will block the new subscriber without allowing access even when the capacity to be accommodated at the same time is exceeded.

When the subscriber who attempts to access the femtocell is unable to access the femtocell AP, the mobile station must proceed to select another cell. However, such a cell reselection process not only increases the load of the mobile station, but also selects an inaccessible femtocell AP instead of another cell when the mobile station fails to access the femtocell AP due to the access acceptance limit of the femtocell AP. There is a problem of being retried. Accordingly, the mobile station does not connect to either the macro cell base station or the femtocell AP, and thus a service blanker is generated which repeats only a process for cell selection without receiving a communication service.

The present invention has been proposed to solve the above problems, when the mobile terminal cannot accept the mobile terminal due to the access capacity limitation of the femtocell AP or the mobile terminal that is not allowed to access the femtocell AP attempts to access the femtocell, the mobile terminal macro An object of the present invention is to provide a frequency shifting method for inducing a connection to a base station of a cell and a system therefor.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

According to a first aspect of the present invention for achieving the above object, in the communication system operating a femtocell, a frequency shifting method for deriving a connection of a mobile terminal that cannot be connected to a femtocell to a macrocell includes (a) a femtocell connection request from a mobile terminal; Receiving a message; (b) determining whether the mobile terminal is accessible to the femtocell; (c) extracting a macrocell frequency accessible by the mobile terminal when it is impossible to connect; And (d) shifting the access frequency of the mobile terminal to the extracted macrocell frequency.

According to a second aspect of the present invention for achieving the above object, in the femtocell service environment, a frequency shifting system for inducing access to a mobile terminal that is not accessible to a femtocell to a macrocell, a femtocell for authenticating femtocell access authority for each mobile terminal Authentication server; And requesting authentication of the mobile terminal attempting to connect to the femtocell to the femtocell authentication server, and when the mobile terminal is an unauthorized access terminal as a result of the authentication, extracting a macrocell frequency to extract the access frequency of the mobile terminal. And a femtocell base station transitioning to a frequency.

According to a third aspect of the present invention for achieving the above object, a femtocell base station apparatus for inducing a connection to a mobile terminal that is not accessible to a femtocell in a femtocell service environment, the femtocell base station apparatus, the terminal connection processing unit for receiving a connection request from the mobile terminal; An authentication unit to determine whether the mobile terminal can be connected; And a frequency shifter for extracting the macrocell frequency and converting the access frequency of the mobile terminal to the extracted macrocell frequency when it is impossible to connect.

According to the present invention, a mobile terminal that cannot be connected to a femtocell is connected to a macrocell, thereby minimizing service white space of the mobile terminal caused by retrying unnecessary connection to the femtocell.

In addition, the present invention has the advantage of reducing the load of the mobile terminal generated during reselection by transmitting the macrocell frequency information with the strongest signal strength to the mobile terminal that can not be connected to the femtocell and connecting the mobile terminal at that frequency.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a configuration of a frequency shifting system for accessing a mobile terminal inaccessible to a femtocell to a macrocell in a femtocell service environment according to an embodiment of the present invention.

As shown in FIG. 1, the frequency shifting system according to the preferred embodiment of the present invention includes a macrocell base station 120, a femtocell AP 131, a base station controller 200, an exchange 300, a gateway 400, and a femtocell. The authentication server 600 is included.

The base station 120 is a BTS (Base Station Transceiver Subsystem) or NodeB, which manages radio resources and is controlled by the control of the base station controller 200. In addition, the base station controller 200 is a base station controller (BSC) or a radio network controller (RNC), which allocates and releases radio channels to the mobile station 110 and controls transmission outputs of the mobile station 110 and the base station 120. It performs inter-cell soft handoff and hard handoff determination, transcoding and vocoding, and operation and maintenance functions for the base station 120.

The exchange 300 is a mobile switching center (MSC) or a serving GPRS support node (SGSN), and provides an interface function with the base station controller 200, and controls voice calls, data transmission and reception, and various additional services.

The gateway 400 connects the wired broadband network 500 and the mobile communication core network, and the mobile terminal 110 connected to the femtocell AP 131 and the mobile terminal 110 connected to the mobile communication core network. Enable communication between In addition, the gateway 400 transmits data (for example, Internet content) received through the wired broadband network 500 to the mobile terminal 110 connected to the mobile communication core network. In addition, the gateway 400 transmits data (eg, mobile content) received through the mobile communication core network to the mobile terminal 110 connected to the femtocell AP 131. In addition, the gateway 400 performs a protocol conversion function between the mobile communication core network and the wired broadband network 500.

The femtocell AP 131 is mainly for the purpose of guaranteeing the quality of mobile communication services in areas or shadowed areas where the radio wave of the macro cell base station 120 is degraded, such as inside a home or building, or providing a low rate such as a femtozone service. A femtocell base station utilized for the purpose of connecting to a wired broadband network 500 which is a general-purpose Internet circuit. The mobile terminal 110 entering the femtocell region 130 is connected to the femtocell AP 131 and is connected to a wired broadband line and a mobile communication core network through the femtocell AP 131. In general, the femtocell AP 131 supports one frequency, and due to the small coverage, the number of concurrent users (typically four) is smaller than that of the macrocell base station 120.

The femtocell AP 131 stores a neighbor list, which is information of neighboring macrocells 100, and sets radio resource control (RRC) with the mobile station 110 to allocate radio resources. In addition, the femtocell AP 131 transmits the authentication request message of the mobile terminal 110 attempting to access the femtocell authentication server 600, and receives the authentication result message accordingly. In this case, when the femtocell AP 131 receives the access permission message from the femtocell authentication server 600, the femtocell AP 131 maintains the connection with the mobile terminal 110 and performs the femtocell service through the wired broadband network 500. To provide.

On the contrary, when the femtocell AP 131 receives the connection disable message from the femtocell authentication server 600, the femtocell AP 131 releases the connection with the mobile terminal 110 and connects the mobile terminal 110 to the macrocell base station 120. In this case, the femtocell AP 131 refers to a neighbor list, and transmits the macrocell frequency information of which the signal is strong to the mobile station 110 by including the RRC connection release message in the RRC connection release message. The communication frequency of the mobile terminal 110 is shifted to the macro cell frequency.

Meanwhile, the femtocell AP 131 may be called a micro base station, a pico base station, a ubicell base station, a femtocell base station, or the like according to a policy of a manufacturer or a communication service provider. The femtocell 130 may also be called a picocell, ubicell, or the like. Therefore, the femtocell according to the present invention should be understood as being applicable to the case where the femtocell is connected to the core network of the communication system through the general-purpose Internet line and provides the communication service to the mobile terminal 110.

The femtocell authentication server 700 stores information of the mobile terminal 110 accessible by each femtocell AP 131. In particular, when the femtocell authentication server 600 receives the authentication request message of the mobile terminal 110 from the femtocell AP 131, and authenticates whether the mobile terminal 110 is accessible to the femtocell AP 131, authentication The result message (access grant message or access disable message) is transmitted to the femtocell AP 131.

FIG. 2 is a flowchart illustrating a method of connecting a mobile terminal, which cannot be connected to a femtocell, to a macrocell in a frequency shifting system according to an embodiment of the present invention.

Referring to FIG. 2, the mobile terminal 110 is connected to the femtocell AP 131 to receive a specific service such as a call connection, a wireless Internet connection, or the like to hand over to the femtocell AP 131 through the femtocell AP 131. The RRC connection is established and radio resources are allocated (S201). At this time, the mobile terminal 110 communicates with the femtocell AP 131 using the femtocell frequency (F2). The mobile terminal 110 requests the femtocell AP 131 for a service request or location registration for handover (S203).

Then, the femtocell AP 131 checks whether the total number of subscribers currently connected exceeds the maximum number of accessors, that is, whether the access capacity exceeds the maximum number of accessors due to the access of the mobile terminal 110 (S205). Subsequently, if the access capacity is not exceeded, the femtocell AP 131 requests the femtocell authentication server 600 for authentication of the access authority of the mobile terminal 110 (S207). At this time, the femtocell AP 131 transmits the identifier and the femtocell identifier of the mobile terminal 110 to the femtocell authentication server 600. Then, the femtocell authentication server 600 authenticates the access authority of the mobile terminal 110 to the femtocell AP 131, and transmits an authentication result (access grant message or access impossible message) to the femtocell AP 131 ( S209).

The femtocell AP 131 checks whether the message received from the femtocell authentication server 600 is an access grant or access disable message, and if the message is not accessible, the femtocell AP 131 refers to a neighbor list and selects a frequency having the largest signal strength among the frequencies of the macrocell base station. Extraction (S211, S213).

On the other hand, in step S205, when the femtocell AP 131 is determined that the access capacity exceeds the maximum number of users, the femtocell AP 131 immediately performs step S213 without a procedure (S207 to S211) to check whether the mobile terminal 110 access rights. . That is, if the femtocell AP 131 exceeds the access capacity or the terminal 110 is not allowed to access, the femtocell AP 131 extracts the macrocell frequency with reference to the neighbor list.

Next, the femtocell AP 131 transmits an RRC connection release message (RRC Connection Release) recorded with the extracted macrocell frequency to the mobile terminal 110 (S215). In this case, the femtocell AP 131 records and transmits macrocell frequency information of the mobile station 110 in "Redirection Info" included in the RRC connection release message.

In response, the mobile station 110 transmits an RRC connection release complete message to the femtocell AP 131 and releases the established RRC connection with the femtocell AP 131 (S217). The mobile station 110 refers to the macrocell frequency included in the received RRC connection release message, and accesses the macrocell base station 120 using the frequency as a communication frequency (S219). For example, the mobile terminal 110 receives the RRC connection release message including the F1 frequency information from the femtocell AP 131 in a state where the femtocell AP 131 establishes an RRC connection with the femtocell AP 131 in the femtocell region 130. In one case, the mobile terminal 110 communicates with the macro cell base station 120 by shifting the communication frequency to F1.

On the other hand, when the femtocell AP 131 receives the access permission message of the mobile terminal 110 from the femtocell authentication server 600 does not exceed the maximum number of users, the mobile terminal 110 provides the service requested by the mobile terminal 110. Or proceed with the location registration procedure of the mobile terminal 110 that attempted handover (S221).

3 is a flowchart illustrating a method for selectively performing connection processing according to whether a mobile terminal can be accessed in a femtocell AP according to an embodiment of the present invention.

Referring to FIG. 3, the femtocell AP 131 receives an RRC Connection Request message from the mobile terminal 110 and sets an RRC connection with the mobile terminal 110 to allocate radio resources (S301). . Subsequently, the femtocell AP 131 checks whether the number of simultaneous users exceeds the maximum number of users due to the access request of the mobile terminal 110 (S303).

If the femtocell AP 131 can accommodate the connection of the mobile terminal 110 (that is, if the number of simultaneous users is less than or equal to the maximum number of users), the femtocell authentication server 600 relates to whether the mobile terminal 110 has access authority. Request authentication and receive an authentication result (S305). Next, when the femtocell AP 131 receives an access permission message indicating that the mobile terminal 110 is an access permission terminal from the femtocell authentication server 600, the femtocell AP 131 maintains the connection with the mobile terminal 110 and maintains the connection with the mobile terminal 110. 110 provides the requested service (S307, S309).

On the other hand, the femtocell AP 131 may exceed the maximum number of accessors due to the connection of the mobile terminal 110, or receive a connection unavailable message of the mobile terminal 110 from the femtocell authentication server 600. In operation S311, the macro cell frequency is extracted with reference to the neighbor list. At this time, the femtocell AP 131 extracts the macrocell frequency having the strongest signal strength among the macrocell frequencies of the neighbor list. Subsequently, the femtocell AP 131 transmits the extracted macrocell frequency to the mobile station 110 by including the RRC connection release message in the RRC connection release message, thereby releasing the connection with the mobile station 110 and transmitting the mobile station 110. ) Is connected to the macro cell base station 120 corresponding to the macro cell frequency (S313).

4 is a diagram illustrating a configuration of a femtocell AP for selectively accessing a mobile terminal according to whether the mobile terminal can be connected according to an embodiment of the present invention.

As shown in FIG. 4, the femtocell AP 131 according to an embodiment of the present invention uses a terminal access processing unit 410, a connection authentication unit 430, a neighbor list 450, and a frequency shifting unit 470. Include.

The terminal access processor 410 performs the functions of the macro cell base station 120 and the base station controller 200 to communicate with the mobile terminal 110 entering the femtocell 110 to allocate radio resources, and the mobile terminal 110. Connects to the communication system.

When the access authentication unit 430 receives a connection request from the mobile terminal 110 in the terminal access processing unit 410, the access authentication unit 430 checks whether the capacity for accessing the femtocell AP 131 exceeds the maximum number of accessors, and if it is exceeded, shifts the frequency. The unit 470 indicates the frequency shift of the mobile terminal 110. In addition, the connection authentication unit 430 requests the femtocell authentication server 600 to authenticate the mobile terminal 110 that is requested to be connected, and confirms whether the mobile terminal 110 is a terminal that is allowed to access and does not allow access. In the case of a terminal, the frequency shifter 470 instructs the frequency shift of the mobile terminal 110. That is, if the femtocell access capacity exceeds the maximum number of accessors or the mobile terminal 110 is determined to be an unauthorized access terminal according to the access request of the mobile terminal 110, the access authentication unit 430 determines the frequency transition unit 470. ) Indicates a frequency shift of the mobile terminal 110.

The neighbor list 450 stores the macrocell frequency around the femtocell 130 and the signal strength of the frequency.

The frequency shifting unit 470 searches for the macrocell frequency around the femtocell 130 and the signal strength of the frequency at regular intervals and stores them in the neighbor list. In particular, the frequency shifting unit 470 shifts the communication frequency of the mobile terminal 110 from the femtocell frequency to the macrocell frequency according to the instruction of the access authenticator 430. In detail, the frequency shifter 470 extracts the macrocell frequency having the strongest signal strength with reference to the neighbor list 450, and sends an RRC connection release message including the detected macrocell frequency to the mobile terminal 110. By transmitting, the connection with the mobile terminal 110 is released and the communication frequency of the mobile terminal 110 is shifted to the macro cell 100 frequency.

Meanwhile, in the above-described embodiment, the femtocell AP 131 has been described as requesting the access authority of the mobile terminal 110 to the femtocell authentication server 600, but the femtocell AP 131 has the access authority. The information may be stored, and the access authority of the mobile terminal 110 may be authenticated on its own. That is, the femtocell AP 131 not only checks the capacity for connection, but also directly authenticates the access authority of the mobile terminal 110, and if one of the two is not satisfied, the femtocell AP 131 disconnects the mobile terminal 110 and the mobile terminal ( Transmit the communication frequency of 110 to the macro cell base station frequency.

The method of the present invention as described above may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

While the specification contains many features, such features should not be construed as limiting the scope of the invention or the scope of the claims. Also, the features described in the individual embodiments herein can be implemented in combination in a single embodiment. Conversely, various features described herein in a single embodiment may be implemented in various embodiments individually or in a suitable subcombination.

In addition, although the operations are described in a specific order in the drawings, it is to be understood that such operations are performed in a specific order as shown, or that a series of consecutive orders, or all described operations, are performed to obtain a desired result. No. In some circumstances, multitasking and parallel processing may be advantageous. In addition, it should be understood that the division of various system components in the above-described embodiments does not require such division in all embodiments. The above-described program components and systems can generally be implemented as a single software product or as a package in multiple software products.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

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. It should not be construed as limited to.

1 is a diagram illustrating a configuration of a frequency shifting system for accessing a mobile terminal inaccessible to a femtocell to a macrocell in a femtocell service environment according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a method of connecting a mobile terminal, which cannot be connected to a femtocell, to a macrocell in a frequency shifting system according to an embodiment of the present invention.

3 is a flowchart illustrating a method for selectively performing connection processing according to whether a mobile terminal can be accessed in a femtocell AP according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of a femtocell AP for selectively accessing a mobile terminal according to whether the mobile terminal can be connected according to an embodiment of the present invention.

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

120: macrocell base station 131: femtocell AP

200: base station controller 300: switchboard

400: gateway 600: femtocell authentication server

410: terminal connection processing unit 430: connection authentication unit

450: Naver list 470: frequency transition unit

Claims (12)

A frequency shifting method for inducing a connection of a mobile terminal that cannot be connected to a femtocell to a macrocell in a communication system operating a femtocell, (a) receiving a femtocell connection request message from a mobile terminal; (b) determining whether the mobile terminal is accessible to the femtocell; (c) searching for a macrocell frequency around the femtocell and extracting a macrocell frequency having a strong signal strength if the accessor capacity of the femtocell is exceeded or if the mobile terminal is an unacceptable terminal; ; And (d) shifting the access frequency of the mobile terminal to the extracted macrocell frequency. delete delete The method of claim 1, In step (d), And recording the macrocell frequency in an RRC connection release message and transmitting the macrocell frequency to the mobile station to shift the access frequency of the mobile station to the macrocell frequency. A frequency shifting system for inducing a connection of a mobile terminal that cannot be connected to a femtocell to a macrocell in a femtocell service environment, A femtocell authentication server for authenticating femtocell access authority for each mobile terminal; And Request the authentication of the mobile terminal attempting to access the femtocell to the femtocell authentication server, and if the mobile terminal is a terminal that is not allowed access or the accessor capacity is exceeded, the neighboring macrocell frequency is searched and the signal strength of And a femtocell base station for extracting a strong macrocell frequency and shifting the access frequency of the mobile station to the extracted macrocell frequency. delete delete The method of claim 5, The femtocell base station, And recording the macrocell frequency in an RRC connection release message and transmitting the macrocell frequency to the mobile terminal to shift the access frequency of the mobile terminal to the macrocell frequency. A femtocell base station apparatus for inducing a connection to a mobile terminal that is not accessible to a femtocell in a femtocell service environment, A terminal connection processing unit receiving a connection request from a mobile terminal; An authentication unit to determine whether the mobile terminal can be connected; And As a result of the determination of the authentication unit, when the accessor capacity is exceeded or the mobile terminal is a terminal that is not allowed to access, the neighboring macrocell frequency is searched and the macrocell frequency having the strongest signal strength is extracted to determine the access frequency of the mobile terminal. And a frequency shifting unit for shifting to the extracted macrocell frequency. delete delete The method of claim 9, The frequency shifting unit, And recording the macrocell frequency in an RRC connection release message and transmitting the macrocell frequency to the mobile station to transition the access frequency of the mobile station to the macrocell frequency.

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