KR101265624B1 - Method and Mobile Telecommunication Terminal Performing Hand-over in Mobile Internet System - Google Patents

Abstract

The present invention relates to a method for performing handover of a mobile communication terminal in a portable internet system and a mobile communication terminal using the same.

The present invention provides a method for selecting a predetermined neighbor base station by using scanning result information of neighboring base stations stored when the network entry fails through handover, and the information retention period of the serving base station by the serving base station is increased. Determining whether it has expired, performing a handover through the selected neighbor base station if it is determined that it has not expired, and performing an initial network entry through the selected neighbor base station when it is determined that it has expired Provided is a method for performing handover of a mobile communication terminal in a portable internet system including a step of performing the same, and a mobile communication terminal using the same.

Therefore, according to the present invention, it is possible to quickly perform network connection in case of handover failure.

Portable Internet Systems, Handovers, Information Retention Periods

Description

A method of performing a handover of a mobile communication terminal in a portable internet system and a mobile communication terminal using the same {Method and Mobile Telecommunication Terminal Performing Hand-over in Mobile Internet System}

1 is a configuration diagram of a mobile communication terminal having a handover function in a portable Internet system according to the present invention.

2 is a flowchart illustrating a handover method of a mobile communication terminal in a portable Internet system according to the present invention.

3A is an exemplary structural diagram of a handover request message according to the present invention;

3B is a structural diagram of an embodiment of a handover response message according to the present invention;

4 is a diagram illustrating an information retention period according to the present invention.

5 is a structural diagram of an embodiment of a terminal registration response message according to the present invention;

6 is another embodiment showing an information retention period according to the present invention;

7 is a flowchart illustrating a handover procedure of a mobile communication terminal according to the prior art.

The present invention relates to a method for performing handover of a mobile communication terminal, and more particularly, to a method for performing handover of a mobile communication terminal in a portable internet system and a mobile communication terminal using the same.

Currently, the mobile terminal can transmit and receive a large amount of data with a base station at high speed through the portable Internet. Examples of communication standards using the portable Internet include WiMAX (WiMAX), Wireless Broadband (WiBro), and the like.

 The WiMAX is a technology method being developed by various companies aiming at the technical standard of the portable Internet in the WiMAX Forum, and complements the existing WLAN technology by allowing a wider radius of the Internet use outside the building. In addition, the WiBro, a wireless portable Internet technology standard being developed by the Ministry of Information and Communication (TTA) and mobile communication companies, provides a service that can use the high-speed Internet on the go.

Accordingly, the technical standard related to the portable Internet enables high-speed wireless Internet access anytime, anywhere, even while stationary and mobile, using various portable Internet terminals such as handsets, notebooks, personal digital assistants, PDAs, and smart phones.

The mobile communication terminal scans neighboring base stations from time to time, and performs handover to a specific neighboring base station according to the result in order to transmit and receive stable data with a predetermined base station through the portable Internet.

Hereinafter, a handover procedure of a mobile communication terminal according to the related art will be described with reference to FIG. 7.

The mobile communication terminal scans adjacent base stations (S710).

In this case, the mobile communication terminal collects information for determining a base station suitable for handover from the neighbor base stations through the scanning process.

The mobile communication terminal stores the scanning result information obtained by the scanning process (S720).

For example, the scanning result information indicates a wireless environment for each of the neighbor base stations. That is, the scanning result information may mean the received signal strength of each of the neighboring base stations scanned.

The mobile communication terminal performs a handover based on the neighboring base station selected from the scanned neighboring base stations (hereinafter, referred to as a 'target base station') based on the scanning result information (S730).

At this time, if it fails to enter the network through the handover (S740), the mobile terminal determines whether the information retention period by the serving base station has expired (S750).

The serving base station refers to a base station that transmits and receives data with the mobile communication terminal through the portable Internet.

In addition, the information holding period means a period in which information on the mobile communication terminal is maintained by the serving base station after determining to perform a handover.

If it is determined that the information retention period has expired, the mobile communication terminal scans the neighbor base stations again (S760), and attempts to enter an initial network based on the result (S770).

On the other hand, if it is determined that the information holding period has not expired, the mobile communication terminal attempts to access the network through the serving base station and maintains data communication with the serving base station (S780).

However, according to the above-described prior art, when the network connection through the handover fails, the network access through the serving base station is attempted again, which is a network connection through the serving base station where the received signal strength is weakened, rather than the network access probability. Dropped.

In addition, even if the network connection through the serving base station is successful, since the reception signal strength of the serving base station is already weakened, the possibility of handover needs to be performed again.

In addition, according to the above-described conventional technology, when the network access through the handover fails, the neighboring base stations must be rescanned for the initial network entry, which increases the time consuming time after the handover failure to enter the new network. Generates.

The present invention is to solve the above problems, in the case of a network connection failure through the handover, using the previously stored scanning result information, attempts to reconnect the network through at least one of the handover and initial network entry To provide a method and a mobile communication terminal.

In addition, the present invention is to solve the above problems, when the network connection failure due to the handover, depending on whether the information retention period expires by the serving base station, the network through at least one of the handover and the initial network entry Another object is to provide a method for attempting reconnection and a mobile communication terminal.

In order to achieve the above object, a method for performing handover of a mobile communication terminal in a portable Internet system according to the present invention uses scanning result information about neighboring base stations stored in advance when network entry through the handover fails. Selecting a predetermined neighbor base station, determining whether the information retention period with the mobile communication terminal by the serving base station has expired, and performing a handover through the selected neighbor base station if it is determined that it has not expired. And performing initial network entry through the selected neighbor base station when it is determined that the determination result has expired.

In addition, in order to achieve the above object, in the present invention, a mobile communication terminal having a handover function in a portable Internet system includes a memory for storing scanning result information obtained as a result of scanning neighboring base stations, and a network via handover. When the entry fails, the control unit for selecting a predetermined neighbor base station using the stored scanning result information, determines whether the information retention period for the mobile terminal has expired and outputs a control signal according to the control unit and the control unit And a network access processing unit that performs one of a handover through the selected neighbor base station and an initial network entry through the selected neighbor base station according to the signal.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the detailed description is abbreviate | omitted about the well-known technique judged that it may blur the summary of this invention.

1, a mobile communication terminal having a handover function in a portable Internet system according to the present invention will be described in detail as follows.

As shown in FIG. 1, the mobile communication terminal includes a memory 110 for storing scanning result information, a controller 120 for outputting various control signals in connection with performing a handover, and a network according to the control signal of the controller. Network connection processing unit 130 for processing the connection, a scanning module 140 for scanning the adjacent base stations in accordance with the control signal of the control unit and a transmission and reception module 150 for transmitting and receiving data with the serving base station in accordance with the control signal of the control unit do.

The memory 110 stores all data input and output to the mobile communication terminal and a program necessary for the operation of each component.

In particular, in the present invention, the memory 110 stores the scanning result information obtained as a result of performing the scanning of the scanning module 150. In addition, the memory 110 stores data and messages transmitted and received between the transmission and reception module 150 and the serving base station through the portable Internet.

For example, the scanning result information is information indicating a wireless environment for each neighboring base station, and the carrier to interference and noise ratio (CINR) value or the received signal strength indication (RSSI) value measured for each neighboring base station is measured. it means. Here, the CINR represents the strength of the received signal considering the signal disturbance factor as the ratio of the received signal to the signal disturbance, and the RSSI represents only the strength of the received signal without considering the signal disturbance.

The controller 120 controls all operations and functions of the mobile communication terminal, and in particular, controls operations related to the mobile Internet.

In particular, in the present invention, when failing to enter the network through the handover, the controller 120 selects a predetermined neighbor base station by using the scanning result information stored in the memory 110.

In this case, the controller 120 selects an adjacent base station having the best wireless environment by using the scanning result information. Meanwhile, it is preferable that the neighbor base station set as the target base station in the failed handover is excluded from the selection target.

For example, the controller 120 may select an adjacent base station having the best CINR or RSSI value. This is because the handover or initial network entry will be performed through the selected neighbor base station. Therefore, it is necessary to select a neighbor base station having the best wireless environment to increase the network access rate. This will be described in detail below.

In particular, in the present invention, the controller 120 determines whether the information retention period of the serving base station for the mobile communication terminal has expired, and outputs a control signal accordingly.

The information holding period is a period which proceeds after the time point at which the handover is determined to be performed, and means a period for maintaining the connection information of the mobile communication terminal by the serving base station of the mobile communication terminal. For example, the time point for determining the handover performance refers to the time point for transmitting a handover confirmation message for finally confirming the handover performance from the mobile communication terminal to the serving base station. In this case, the handover confirmation message is a message established by the Institute of Electrical and Electronics Engineers (IEEE) standard, and may be a MOB_HO_IND message.

Alternatively, the information holding period is a period of time after the connection between the mobile communication terminal and the serving base station is disconnected, and means a period in which the connection information for the mobile communication terminal is maintained by the serving base station.

Hereinafter, referring to FIG. 3A to FIG. 6, it will be described in detail with respect to designation and progress of the information induction period.

3a shows a structure of a handover request message transmitted from the serving base station to the mobile communication terminal.

The handover request message means a message transmitted from the serving base station to request a handover from the mobile communication terminal. In particular, FIG. 3A illustrates a structure of a MOB_BSHO-REQ message as a handover request message established by the IEEE standard.

As shown in FIG. 3A, the handover request message provides information on whether to maintain connection information of the mobile communication terminal for a predetermined period by the serving base station through a Resource Retain Flag field. .

For example, the handover request message includes information indicating that the connection information for the mobile communication terminal is not maintained when the Resource Retain Flag field value is '0', and the Resource Retain Flag field value is '1'. In this case, information for maintaining connection information for the mobile communication terminal is provided.

3b shows a structure of a handover response message transmitted from the serving base station to the mobile communication terminal.

The handover response message refers to a message transmitted to indicate whether to accept or reject a handover request when the mobile communication terminal requests a handover from the serving base station. In particular, FIG. 3B illustrates a structure of a MOB_BSHO-RSP message as a handover response message established by the IEEE standard.

As shown in FIG. 3B, the handover response message provides information on whether to maintain the connection information of the mobile communication terminal by the serving base station for a predetermined period of time through a Resource Retain Flag field. .

For example, the handover response message includes information indicating that the connection information of the mobile communication terminal is not maintained when the Resource Retain Flag field value is '0', and when the Resource Retain Flag field value is '1'. Information is provided to maintain connection information of the mobile communication terminal.

Hereinafter, the progress of the information holding period will be described in detail by dividing the value of the Resource Retain Flag field of the handover request message and the handover response message to '0' and '1'.

First, a case in which the Resource Retain Flag field value is '1' will be described with reference to FIG. 4. When the Resource Retain Flag field value is '1', the serving base station maintains connection information of the mobile communication terminal for a separately designated period.

For example, as shown in Figure 4, the serving base station, when the value of the Resource Retain Time is '0' during the period determined in the initial network registration process, the Resource Retain Time is the value value '1' In the case of ˜255 ', connection information of the mobile communication terminal is maintained for a period separately designated by the serving base station. On the other hand, the maintenance period information for the connection information of the mobile communication terminal is provided from the serving base station to the mobile communication terminal.

5 and 6, a case where the Resource Retain Flag field value is '0' will be described.

When the Resource Retain Flag field value is '0', the serving base station maintains connection information of the mobile communication terminal for a period determined at initial network registration.

More specifically, the mobile communication terminal, when entering the initial network through the serving base station, exchanges predetermined information with the network. In this case, the mobile communication terminal receives information on a system information holding period from the serving base station. Here, the system information holding period is the connection of the mobile communication terminal by the serving base station when the connection between the mobile communication terminal and the serving base station is lost or when the handover performed by the mobile communication terminal fails. The period of time information is maintained. In addition, the information on the system information maintenance period is provided to the mobile communication terminal in the registration step of the initial network access process through the serving base station.

The structure of the terminal registration response message shown in FIG. 5 indicates a structure of a response message transmitted from the serving base station to the mobile terminal in the terminal registration request to the network requested by the mobile terminal. In particular, FIG. 5 shows the structure of a REG-RSP message according to the IEEE standard.

As illustrated in FIG. 5, the terminal registration response message provides information necessary for performing handover through a TLV Encoded Information field.

In this case, the information on the system information holding period corresponds to information necessary for performing the handover. The information on the system information holding period means a System Resource Retain Time defined by the IEEE standard, as shown in FIG.

For example, as shown in FIG. 6, the serving base station maintains connection information of the mobile communication terminal for a predetermined period of time in units of 100 milliseconds. At this time, 200 milliseconds is recommended as the default value.

Therefore, the mobile communication terminal, as described above, is provided with the information on the information retention period from the serving base station, it is possible to determine whether the information retention period has expired.

In particular, in the present invention, the control unit 120 outputs a control signal for commanding a handover through the selected neighboring base station when it is determined that the information retention period has not expired.

In particular, when it is determined that the information retention period is longer than a time required for handover, the controller 120 may output a control signal for commanding handover through the selected neighbor BS.

On the other hand, when it is determined that the information retention period is less than the time required for the handover, the controller 120 may output a control signal for commanding network connection through the serving base station.

In this case, the time required for the handover may be already set in the production process of the mobile communication terminal, or may be determined using time information required for the handover previously performed by the mobile communication terminal.

For example, an average value, a minimum value, and a maximum value for the time required for the handover may be set in the production process or determined from time information required for a handover performed previously. Accordingly, the mobile communication terminal may select one of the average value, the minimum value, and the maximum value according to the received signal strength of an adjacent base station (hereinafter, referred to as a 'target base station') to perform handover. That is, if the received signal strength of the target base station is weak, handover is performed for the target base station for the minimum value.

In particular, in the present invention, when it is determined that the information retention period has expired, the controller 120 outputs a control signal for commanding the initial network entry through the selected neighboring base station.

The network connection processing unit 130 manages network connection of the mobile communication terminal in the portable Internet system.

In particular, in the present invention, the network access processor 130 performs one of a handover through the selected neighbor base station and an initial network entry through the selected neighbor base station according to the control signal of the controller 120.

More specifically, the network connection processing unit 130 according to the control signal of the control unit 120, when not only the information retention period has not expired but the information retention period is longer than the time required to perform the handover, Handover through the selected neighbor base station is performed. Alternatively, the network access processing unit 130, in response to the control signal of the control unit 120, when the information holding period is not expired but the information holding period is less than the time required to perform the handover, the serving base station Perform network connection through

Meanwhile, when it is determined that the information retention period has expired, the network access processing unit 130 performs initial network entry through the selected neighbor base station according to the control signal of the control unit 120.

The scanning module 140 performs scanning on neighboring base stations according to a control signal of the controller 120, and acquires the scanning result information as a result.

In particular, in the present invention, the scanning module 140, according to the control signal of the controller 130, when it fails to enter the initial network performed as determined that the information retention period has expired, for the adjacent base stations The scanning operation can be performed. Accordingly, the network access processor 130 selects a predetermined neighbor base station by using the scanning result information acquired by the scanning module 140 and performs initial network entry through the selected neighbor base station.

The transmission / reception module 150 transmits / receives data with a predetermined base station through a portable internet system.

In general, the predetermined base station means the serving base station.

In particular, in the present invention, prior to performing the handover, the transmission / reception module 150 transmits and receives various messages in a handover negotiation process with the serving base station.

For example, the message transmitted and received in the handover negotiation process means a handover request message, a handover response message, a handover confirmation message, and the like.

Referring to Figure 2, the method for performing handover of the mobile communication terminal in the portable Internet system according to the present invention in detail as follows.

The mobile communication terminal scans adjacent base stations (S205).

The mobile communication terminal obtains scanning result information according to the scanning result.

In addition, the mobile communication terminal acquires information on the neighbor base stations by using a network management message periodically received from a serving base station, and performs the scanning operation on predetermined neighbor base stations adopted based on the information. do.

The mobile communication terminal stores the scanning result information obtained from the scanning result (S210).

The mobile communication terminal stores scanning result information for each of the neighbor base stations.

In this case, the scanning result information is information indicating a radio environment for each neighboring base station, and means a carrier to interference and noise ratio (CINR) value or a received signal strength indication (RSSI) value measured for each neighboring base station. .

The mobile communication terminal performs a handover to a neighbor base station (hereinafter, referred to as a 'target base station') selected based on the stored scanning result information (S215).

Although not shown in the figure, it can be seen that the handover negotiation process between the mobile communication terminal and the serving base station is performed prior to the handover performing step (S215).

The mobile communication terminal fails to enter the network in the process of performing the handover through the target base station (S220).

For example, the mobile communication terminal may fail to enter the network through the target base station in case of exceeding the capacity of the target base station, overload of the entire network, communication between the serving base station and the target base station. In addition, the network entry failure through the target base station may occur in any part of the network entry process as well as the case described above.

The mobile communication terminal selects a predetermined neighbor base station using the stored scanning result information (S225).

In this case, the mobile communication terminal selects an adjacent base station having the best wireless environment using the scanning result information. On the other hand, it is preferable that the neighboring base station set as the target base station in the handover step (S215) is excluded from the selection target.

For example, the controller 120 selects an adjacent base station having the best CINR or RSSI value. This is because it is necessary to select a neighbor base station having the best wireless environment and to increase network access rate because it will attempt to handover through the selected neighbor base station or initial network entry.

The mobile terminal determines whether the information retention period of the serving base station has expired (S230).

The information holding period is a period of time after the time at which the handover is performed or after the connection between the mobile communication terminal and the serving base station is disconnected, and the connection information of the mobile communication terminal is maintained by the serving base station. It means the period of time.

For example, the time at which the handover is determined may mean a time at which the mobile communication terminal transmits a message for finally confirming the handover to the serving base station (hereinafter, 'handover confirmation message'). have. In this case, the handover confirmation message is a message established by the Institute of Electrical and Electronics Engineers (IEEE) standard, and may be a MOB_HO_IND message.

Designation and progression of the information retention period are the same as those described above with reference to FIGS. 3A to 6, and thus detailed description thereof will be omitted below.

When it is determined that the information retention period has not expired, the mobile communication terminal determines whether the information retention period is longer than a time required for performing a handover (S235).

In this case, the time required for the handover may be already determined in the production process of the mobile communication terminal, or may be determined from time information required for the handover previously performed by the mobile communication terminal.

If it is determined that the information holding period is longer than the time required for the handover, the mobile communication terminal performs a handover through the selected neighbor base station (S240).

In case of failing to enter the network in step S240, the mobile communication terminal may select a predetermined neighbor base station again by using the stored scanning result information.

Alternatively, if it is determined that the information retention period is less than the time required for the handover, the mobile communication terminal attempts to access the network through the serving base station (S250).

On the other hand, if it is determined that the information maintenance period has expired, the mobile communication terminal performs initial network entry through the selected neighbor base station (S255).

In the initial network entry step (S255), when the network entry fails (S260), the mobile communication terminal scans the neighbor base stations again (S265).

The mobile communication terminal attempts to enter an initial network through a predetermined neighbor base station using the scanning result information obtained in the scanning step S265 (S270).

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.

According to the present invention described above, when the network connection failure through the handover, using the previously stored scanning result information, attempts to reconnect the network through at least one of the handover and the initial network entry, so as to quickly The network can be reconnected.

In addition, according to the present invention described above, when the network connection failure due to the handover, it is possible to determine whether the information retention period expired by the serving base station, it is possible to selectively perform the handover and initial network entry.

In addition, according to the present invention described above, by comparing the information maintenance period and the time required to perform the handover, it is possible to selectively perform network reconnection through the serving base station and handover through the target base station.

Claims (13)

Selecting a neighboring base station by using the scanning result information about the neighboring base stations stored when the network entry through the first handover fails; And The second handover through the selected neighbor base station, the network connection through the serving base station, or the like, depending on the information retention period with the mobile communication terminal by the serving base station or the time required to perform the second handover to the selected neighbor base station; Performing initial network entry through the selected neighbor base station; It includes, wherein the information maintenance period is a period of time after the time to determine the first handover or after the connection between the mobile communication terminal and the serving base station is disconnected, the mobile communication by the serving base station A method for performing handover of a mobile communication terminal in a portable internet system during a period in which connection information of a terminal is maintained. The method of claim 1, wherein the selecting step, And performing the handover of the mobile communication terminal in the portable internet system, wherein the neighboring base station having the best wireless environment is selected using the scanning result information. The method of claim 1, wherein the information retention period, And a handover confirmation message for finally informing that the mobile terminal performs the first handover is transmitted to the serving base station for a predetermined period of time. According to claim 1, wherein the performing step, And when the information retention period expires, performing initial network entry through the selected neighbor base station. According to claim 1, wherein the performing step, If the information retention period does not expire, if it is determined that the information retention period is longer than the time required for performing the second handover, the second handover is performed. If it is determined that the information retention period is less than the time required for the second handover, a method for performing handover of a mobile communication terminal in a portable Internet system, characterized in that attempting a network connection through a serving base station of the mobile communication terminal. . 5. The method of claim 4, And performing scanning of neighboring base stations when the network entry fails in the initial network entry step. A memory for storing scanning result information obtained as a result of scanning neighboring base stations; In case of failing to enter the network through the first handover, a predetermined neighbor base station is selected using the stored scanning result information, and the information holding period of the serving base station for the mobile communication terminal or the second hand to the selected neighbor base station. A control unit for outputting a signal for controlling to perform an initial network entry through the second handover through the selected neighboring base station, the network connection through the serving base station, or the selected neighboring base station according to the time required to perform the over; And According to a control signal of the control unit, a network connection processing unit for performing one of the second handover through the selected neighbor base station, the network access through the serving base station, the initial network entry through the selected neighbor base station, wherein the information The maintenance period is a period of time after the time at which the first handover is determined or after the connection between the mobile communication terminal and the serving base station is disconnected, and the connection information of the mobile communication terminal is maintained by the serving base station. A mobile communication terminal having a handover function in a portable Internet system which is a period of time. 8. The apparatus of claim 7, A mobile communication terminal having a handover function in the portable Internet system, wherein the neighboring base station having the best wireless environment is selected using the scanning result information. The method of claim 7, wherein the information retention period, A mobile communication terminal having a handover function in a portable Internet system, characterized in that a period of time since the handover confirmation message that finally informs the first handover is transmitted. The method of claim 7, wherein If it is determined that the information retention period has not expired, The control unit outputs a control signal for commanding the second handover through the selected base station, The network access processing unit, according to the control signal of the control unit, the mobile communication terminal having a handover function in the portable Internet system, characterized in that for performing the second handover through the selected neighbor base station. 11. The apparatus according to claim 10, If it is determined that the information retention period is longer than the time required for the second handover, handover is performed in the portable Internet system, wherein a control signal for commanding the second handover through the selected neighbor base station is output. Mobile communication terminal having a function. 11. The method of claim 10, If it is determined that the information retention period is less than the time required for the second handover, The control unit outputs a control signal for commanding network connection through the serving base station, The network connection processing unit, according to the control signal of the control unit, the mobile communication terminal having a handover function in the portable Internet system, characterized in that for performing a network connection via the serving base station. The method of claim 7, wherein If it is determined that the information retention period has expired, The control unit outputs a control signal for commanding initial network entry through the selected neighboring base station, The network access processing unit is a mobile communication terminal having a handover function in the portable Internet system, characterized in that for performing the initial network entry through the selected neighbor base station according to the control signal of the controller.

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