KR20080032807A - Method of reselecting a cell and mobile communication terminal thereof - Google Patents

Abstract

A cell reselection method of a mobile communication terminal and the mobile communication terminal for performing the method are provided to perform cell reselection to a neighbor cell capable of offering an HSDPA(High Speed Downlink Packet Access) service, when a packet data service is executed, thereby increasing a user's probability of receiving the HSDPA service. A wireless transceiver(210) receives cell information from a base station. An input unit(240) demands a data service. If the data service is demanded by the input unit, a controller(230) detects a neighbor cell which supports an HSDPA service based on the cell information received through the wireless transceiver, and reselects the neighbor cell which supports the HSDPA service as a serving cell. A memory unit(250) stores information on the serving cell reselected by the controller. When an HSDPA service is available, the controller makes a display unit(260) display a guide message, which indicates a user can use the current HSDPA service, and a menu screen by which the user selects whether to use the HSDPA service.

Description

Reselection method of a mobile communication terminal and a mobile communication terminal for performing the same {Method of reselecting a cell and mobile communication terminal}

1 is a view schematically showing the configuration of a system to which the present invention is applied;

2 is a block diagram showing the configuration of a mobile communication terminal according to an embodiment of the present invention;

3 is a flowchart provided to explain a method for cell reselection of a mobile communication terminal according to an embodiment of the present invention; and

4 is an example of a menu screen displayed on a mobile communication terminal when a high speed downlink packet access (HSDPA) service is available.

Brief description of the main parts of the drawing

10a-10d: cell 20a-20d: base station

200: mobile communication terminal

The present invention relates to a cell reselection method of a mobile communication terminal and a mobile communication terminal for performing the same.

In a mobile communication system, a base station is divided into cellular compartments with a minimum number of cells serving as a serviceable area. Accordingly, the mobile communication terminal located in the cell area serviced by the predetermined base station performs wireless communication through the corresponding base station, and when moving from one serving cell to another serving cell, a handoff occurs to maintain a call state without disconnection. have.

As such, the mobile communication terminal selects a cell having the largest signal strength and registers it as a serving cell, and then measures the signal strength of the neighbor cell using neighbor cell information and satisfies the cell reselection condition. The neighbor cell is then reselected as the serving cell.

If the serving cell is a cell that does not support the High Speed Downlink Packet Access (HSDPA) service, and there are cells that support the HSDPA service among neighboring cells, the neighbor cell that supports the HSDPA service is the neighboring cell having the largest signal strength. Otherwise, since the cell reselection condition is not satisfied, the mobile communication terminal cannot reselect an adjacent cell supporting the HSDPA service. Accordingly, there is a problem in that the user of the mobile communication terminal cannot receive the HSDPA service.

Therefore, the technical problem to be achieved by the present invention is that the user can receive packet data service through the new network (ex: HSPDA network) when the existing network and newly distributed new network (ex: HSPDA network) is serviced The present invention provides a cell reselection method of a mobile communication terminal and a mobile communication terminal for performing the same.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

Cell reselection method of a mobile communication terminal according to an embodiment of the present invention for achieving the above object comprises the steps of requesting a data service; Check whether the current serving cell is a cell that supports High Speed Downlink Packet Access (HSDPA) service, and if the current serving cell is a cell that does not support the HSDPA service, the HSDPA service is performed among neighbor cells. Detecting a supporting cell; And reselecting a neighbor cell supporting the HSDPA service as a serving cell.

If the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, the neighbor cell supporting the HSDPA service is reselected as a serving cell.

If it is determined that the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, and at the same time there is a possibility of continuously maintaining the state of the serving cell, The neighbor cell supporting the HSDPA service is reselected as the serving cell.

If the following formula is satisfied, the cell reselection method of the mobile communication terminal, characterized in that it is determined that the neighboring cell supporting the HSDPA service is likely to maintain the state of the serving cell:

Qmeas , s ( nonHSDPA cell ) ≤ Qmeas , n ( HSPDA cell ) + Qhyst + Qoffset , n

Where Qmeas , s ( nonHSDPA cell ) indicates the signal strength of the current serving cell that does not support HSDPA service, and Qmeas , n ( HSPDA cell ) satisfies the serving cell criterion (S-Criteria) specified in 3GPP TS 25.304 V5.2.3.1.2, and indicates the signal strength of an adjacent cell supporting HSDPA service, and Qhyst and Qoffset , n are networks It is a value set arbitrarily by, and generally has a constant value irrespective of cell when the networks are the same.

And if the neighbor cell supporting the HSDPA service is reselected as the serving cell, indicating that the HSDPA service is available.

An icon, a menu screen, or a pop-up window indicating that the HSDPA service is available is displayed to indicate that the HSDPA service is available.

The system information received from the base station of the serving cell or the base station of the neighboring cell is checked to determine whether the serving cell or the neighboring cell supports the HSDPA service.

Mobile communication terminal according to an embodiment of the present invention includes a wireless transceiver for receiving cell information from the base station; An input unit for requesting a data service; And when a data service is requested from the input unit, detects an adjacent cell supporting a high speed downlink packet access (HSDPA) service based on cell information received through the wireless transceiver, and converts a neighbor cell supporting the HSDPA service into a serving cell. Control unit for reselecting.

And a memory unit for storing information of the serving cell reselected by the controller.

If the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) as defined in 3GPP TS 25.304 V5.2.3.1.2, the controller returns the neighbor cell supporting the HSDPA service as a serving cell. Choose.

The controller determines that an adjacent cell supporting the HSDPA service satisfies a serving cell criterion (S-Criteria) as defined in 3GPP TS 25.304 V5.2.3.1.2, and at the same time may continue to maintain the state of the serving cell. In this case, the neighbor cell supporting the HSDPA service is reselected as a serving cell.

The control unit determines that the neighbor cell supporting the HSDPA service may continuously maintain the state of the serving cell when the following equation is satisfied:

Qmeas , s ( nonHSDPA cell ) ≤ Qmeas , n ( HSPDA cell ) + Qhyst + Qoffset , n

Where Qmeas , s ( nonHSDPA cell ) indicates the signal strength of the current serving cell that does not support HSDPA service, and Qmeas , n ( HSPDA cell ) satisfies the serving cell criterion (S-Criteria) specified in 3GPP TS 25.304 V5.2.3.1.2, and indicates the signal strength of an adjacent cell supporting HSDPA service, and Qhyst and Qoffset , n are networks It is a value set arbitrarily by, and generally has a constant value irrespective of cell when the networks are the same.

If the neighbor cell supporting the HSDPA service by the control unit is reselected as a serving cell, the display unit for indicating that the HSDPA service is available; further includes.

Hereinafter, with reference to the accompanying drawings illustrating the present invention.

1 is a view schematically showing the configuration of a system to which the present invention is applied.

Referring to FIG. 1, the present system is divided into cellular partitions using cells 10a-10e serving as minimum units of base stations 20a-20e. The mobile communication terminal 200 receives a communication service from one of these cells, and a cell that provides a communication service to the mobile communication terminal 200 is called a serving cell.

For example, if the serving cell is 10a, the surrounding cells 10b to 10e become neighbor cells. In addition, in this embodiment, each of the cells 10a to 10e may or may not support the HSDPA service.

In the present embodiment, the mobile communication terminal 200 checks the system information in the BCCH (Broad Casting Channel) of the control channels received from the base stations 20a to 20e of the respective cells 10a to 10e. It is checked whether the cells 10a to 10e support the HSDPA service.

Meanwhile, the mobile communication terminal 200 performs wireless communication through a base station of a serving cell, and handoff occurs when moving from a serving cell to another cell. At this time, the mobile communication terminal 200 communicates with the base station of the serving cell, selects a neighbor cell having the largest signal strength, and selects the neighbor cell through system information received from the base station of the neighboring cell. The handoff is performed by collecting information of the cell and requesting call establishment.

2 is a block diagram showing the configuration of a mobile communication terminal according to an embodiment of the present invention.

Referring to FIG. 2, the mobile communication terminal 200 includes a wireless transceiver 210, a data processor 220, a controller 230, an inputter 240, a memory 250, a display 260, and An audio processor 270 is included.

The wireless transceiver 210 performs a communication function of the mobile communication terminal 200. The wireless transceiver 210 includes an RF transmitter for upconverting and amplifying a frequency of a transmitted signal, and an RF receiver for low noise amplifying and downconverting a received signal. In this embodiment, the wireless transceiver 210 receives the radio signal transmitted from the base station and transmits to the controller 230.

The controller 230 performs overall control of the mobile communication terminal 200 and may include the above-described data processor 220.

In the present embodiment, the control unit 230 checks the BCCH (Borad Casting Channel) received from the specific base station through the wireless transceiver 210, and confirms the cell-related information. If the cell is a serviceable cell, the controller 230 registers the cell as a serving cell.

In addition, the controller 230 checks whether the serving cell and the neighboring neighboring cells support the HSDPA service by using system information in the BCCH. There is a field called 'HSDPA cell indicator' in the system information. Through this field, it can be checked whether the cell supports the HSDPA service.

The input unit 240 includes various buttons for inputting numeric and text information and function buttons for setting various functions. The input unit 240 may be implemented as a keypad including a direction key, a jog dial, a touch screen, a joystick, and the like.

In an embodiment of the present invention, the input unit 240 receives a data service connection request such as a wireless Internet access request from the user and transmits it to the controller 230. In addition, the input unit 240 receives a user's selection regarding whether to use the HSDPA service and transmits it to the controller 230.

The memory unit 250 includes a program memory and a data memory. Programs are stored in the program memory for controlling general operations of the mobile communication terminal 200. In an embodiment of the present invention, the memory unit 250 stores an application program for performing various data services. In addition, the memory unit 250 stores the serving cell registered by the controller 230.

The display unit 260 outputs various display information, various menu screens, etc. output from the mobile communication terminal 200, and includes a liquid crystal display (LCD) or an organic light emitting diode (OLED). In addition, the display unit 260 may include two or more display devices, including an external display unit and an internal display unit.

In an embodiment of the present invention, when the display unit 260 can receive the HSDPA service, the user selects whether to use the HSDPA service with a guide message that the current HSDPA service is available under the control of the controller 230. To display a menu screen. In addition, when the HSDPA service is available, the display unit 260 displays that the HSDPA service is available in the form of an icon.

The audio processor 270 reproduces the audio signal decoded by the data processor 220 through the speaker SPK or transmits the audio signal generated from the microphone MIC to the data processor 220.

3 is a flowchart provided to explain a cell reselection method of a mobile communication terminal according to an embodiment of the present invention.

Referring to FIG. 3, first, when there is a packet exchange data service request (ex: internet access request) from the user of the mobile communication terminal 200 through the input unit 240 (S305: Y), the controller 230 The system information (system information) provided from the base station of the current serving cell is checked to determine whether the current serving cell is an HSDPA cell (S310).

More specifically, the controller 230 checks the 'HSDPA cell indicator' field in the system information and checks whether the corresponding cell supports the HSDPA service. In the present embodiment, the serving cell refers to a cell belonging to the service area of the base station that currently provides a communication service to the mobile communication terminal 200, and the HSDPA cell refers to a cell capable of providing an HSDPA service.

When the current serving cell is the HSDPA cell (S315: Y), the controller 230 controls the radio transceiver 210 to request the packet data service from the base station of the serving cell, and thus the mobile communication terminal 200 the serving cell. It is possible to receive the data packet service from the base station of the HSDPA scheme (S320).

On the contrary, when the current serving cell is not the HSDPA cell (S315: N), the controller 230 checks the system information provided from the base station of the neighboring cell and searches for the HSDPA cell among the neighboring cells (S325). ). The system information can be confirmed through a BCCH (Broad Casting Channel) of the control channel transmitted by the base station.

When the HSDPA cell is found among the neighboring cells (S330: Y), the controller 230 detects the HSDPA cell having the strongest signal strength among the HSDPA cells (S340).

The controller 230 checks whether the HSDPA cell detected in step S340 satisfies a serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2 (S345). Serving cell reference (S-Criteria) means the minimum cell power to be a serving cell, the description thereof is described in detail in the 3GPP TS 25.304 V5.2.3.1.2 will be omitted. That is, in order for the HSDPA cell detected in step S340 to satisfy the serving cell criterion, the signal size of the HSDPA cell should be larger than the minimum signal size to become the serving cell.

If the detected HSDPA cell does not satisfy the above-mentioned serving cell criterion (S-Criteria) (S350: N), a packet switched data service is performed through the non-HSDPA cell which is the current serving cell (S335).

If the detected HSDPA cell satisfies the above-mentioned serving cell criterion (S-Criteria) (S350: Y), the controller 230 checks whether the detected HSDPA cell can maintain the state of the serving cell. It is checked whether the conditions specified by Equation 1 below are satisfied (S355).

Qmeas , s ( nonHSDPA cell ) ≤ Qmeas , n ( HSPDA cell ) + Qhyst + Qoffset , n

In Equation 1, Qmeas , s ( nonHSDPA cell ) represents the signal strength of the non-HSDPA cell that is the current serving cell, and Qmeas , n ( HSPDA cell ) represents the signal strength of the HSDPA cell satisfying the serving cell criterion (S-Criteria) in step S350.

Qhyst , Qoffset , and n are parameters used to prevent the cell reselection process from occurring too frequently, and are randomly set by the network for each cell, and generally have a constant value regardless of the cells when the networks are the same. .

In this embodiment, if the HSDPA cell does not satisfy the condition of Equation 1, since the HSDPA cell cannot be assumed to be the cell having the maximum signal strength, even if the HSDPA cell is forcibly selected as the serving cell, 3GPP TS 25.304 V5.2.6 According to the cell reselection criterion (R-Criteria) of .1.4, there is a possibility that the mobile terminal may perform the cell reselection process to the non-HSDPA cell again.

Therefore, in the present embodiment, when the HSDPA cell does not satisfy the condition of Equation 1, that is, when it is determined that the state of the serving cell cannot be maintained continuously (S360: N), the PS is transmitted through the non-HSDPA cell which is the current serving cell. Data service is performed (S335).

On the contrary, if the HSDPA cell satisfies the condition of Equation 1, even after the cell reselection is forcibly performed as the HSDPA cell, it is possible to continuously maintain the state of the serving cell. This is possible in the opposite interpretation of the cell reselection criterion (R-Criteria) of 3GPP TS 25.304 V4.2.6.1.4.

As such, when it is determined that the HSDPA cell can continuously maintain the state of the serving cell by satisfying the condition of Equation 1 (S360: Y), the controller 230 of the mobile communication terminal 200 is currently using the HSDPA service. A possibility is displayed on the display unit 260 (S365).

4 is an example of a menu screen displayed when the HSDPA service is available.

Referring to FIG. 4, the menu screen 400 allows the user to select whether to use the HSDPA service together with a guide message that the current HSDPA service is available. In addition, an indicator area 410 indicating that the HSDPA service is available is displayed in the indicator area of the menu screen 400.

When the user selects 'Yes' through the input unit 240 to request the HSDPA service in the menu screen 400 (S370: Y), the controller 230 designates the corresponding HSDPA cell as the serving cell, and then the serving cell HSDPA. Control to perform the HSDPA service through the cell (S375).

In contrast, when the user selects 'No' through the input unit 240 on the menu screen 400, the controller 230 controls the packet data service to be performed through the non-HSDPA cell which is the current serving cell (S335).

As such, when an HSDPA cell having the strongest signal strength is detected, the controller 230 determines whether the detected HSDPA cell satisfies a predetermined condition, and when the predetermined condition is satisfied, the HSPDA cell Even if the cell reselection criteria specified in 3GPP TS 25.304 V5.2.6.1.4 are not met, cell reselection is forcibly performed by the corresponding HSDPA cell so that the mobile communication terminal 200 can receive HSDPA service. do.

On the other hand, in the above-described embodiment, steps S355 to S360 are optional in reselecting the detected HSPDA cells.

In the above-described embodiment, the description has been focused on HSDPA as a data service that a user of the mobile communication terminal wants to provide, but the technical idea of the present invention is not limited thereto. That is, if a new data service is developed at a higher speed than the HSDPA service in the future, and this data service is mixed with an existing service, a new data service may be provided if the user wants to receive a newly developed new data service. The process of selecting a cell may be equally applied to the inventive concept.

As described above, according to an embodiment of the present invention, when there is a cell capable of HSDPA service among neighboring cells when performing packet data service, a cell reselection is performed to a neighbor cell capable of HSDPA service. Has the advantage of increasing the likelihood of receiving HSDPA services.

In the above description of the preferred embodiment of the present invention, the present invention is not limited to the above-described specific embodiment, it is common in the art to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (13)

Requesting a data service; Check whether the current serving cell is a cell that supports High Speed Downlink Packet Access (HSDPA) service, and if the current serving cell is a cell that does not support the HSDPA service, the HSDPA service is performed among neighbor cells. Detecting a supporting cell; And Reselecting a neighboring cell supporting the HSDPA service as a serving cell. Cell reselection method of a mobile communication terminal comprising a. The method of claim 1, If a neighbor cell supporting the HSDPA service satisfies a serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, the neighbor cell supporting the HSDPA service is reselected as a serving cell. A cell reselection method of a mobile communication terminal. The method of claim 1, If it is determined that the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, and at the same time there is a possibility of continuously maintaining the state of the serving cell, A cell reselection method of a mobile communication terminal, wherein the neighbor cell supporting the HSDPA service is reselected as a serving cell. The method of claim 3, If the following formula is satisfied, the cell reselection method of the mobile communication terminal, characterized in that it is determined that the neighboring cell supporting the HSDPA service is likely to maintain the state of the serving cell: Qmeas , s ( nonHSDPA cell ) ≤ Qmeas , n ( HSPDA cell ) + Qhyst + Qoffset , n Where Qmeas , s ( nonHSDPA cell ) indicates the signal strength of the current serving cell that does not support HSDPA service, and Qmeas , n ( HSPDA cell ) satisfies the serving cell criterion (S-Criteria) specified in 3GPP TS 25.304 V5.2.3.1.2, and indicates the signal strength of an adjacent cell supporting HSDPA service, and Qhyst and Qoffset , n are networks It is a value set arbitrarily by, and generally has a constant value irrespective of cell when the networks are the same. The method of claim 1, If the neighbor cell supporting the HSDPA service is reselected as the serving cell, indicating that the HSDPA service is available; the cell reselection method of the mobile communication terminal further comprising: The method of claim 5, A method of reselecting a cell of a mobile communication terminal, characterized by indicating that the HSDPA service is available by using an icon, a menu screen, or a pop-up window indicating that the HSDPA service is available. The method of claim 1, A cell of a mobile communication terminal, by checking system information received from a base station of the serving cell or a base station of the neighboring cell, and confirming whether the serving cell or the neighboring cell supports the HSDPA service. Reselection method. A wireless transceiver for receiving cell information from a base station; An input unit for requesting a data service; And When a data service is requested from the input unit, the neighbor cell supporting the High Speed Downlink Packet Access (HSDPA) service is detected based on the cell information received through the radio transceiver, and the neighbor cell supporting the HSDPA service is returned to the serving cell. And a control unit for selecting. The method of claim 8, And a memory unit for storing information of the serving cell reselected by the controller. The method of claim 8, wherein the control unit, If the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, the neighbor cell supporting the HSDPA service is reselected as a serving cell. Mobile communication terminal. The method of claim 8, wherein the control unit, If it is determined that the neighbor cell supporting the HSDPA service satisfies the serving cell criterion (S-Criteria) defined in 3GPP TS 25.304 V5.2.3.1.2, and at the same time there is a possibility of continuously maintaining the state of the serving cell, A mobile communication terminal, characterized in that reselecting a neighboring cell supporting the HSDPA service as a serving cell. The method of claim 11, wherein the control unit, If the following formula is satisfied, the mobile communication terminal, characterized in that it is determined that the neighboring cell supporting the HSDPA service is likely to maintain the state of the serving cell: Qmeas , s ( nonHSDPA cell ) ≤ Qmeas , n ( HSPDA cell ) + Qhyst + Qoffset , n Where Qmeas , s ( nonHSDPA cell ) indicates the signal strength of the current serving cell that does not support HSDPA service, and Qmeas , n ( HSPDA cell ) satisfies the serving cell criterion (S-Criteria) specified in 3GPP TS 25.304 V5.2.3.1.2, and indicates the signal strength of an adjacent cell that supports HSDPA service, and Qhyst and Qoffset , n are network It is a value set arbitrarily by, and generally has a constant value irrespective of cell when the networks are the same. The method of claim 8, And displaying, by the controller, a neighboring cell supporting the HSDPA service as the serving cell, indicating that the HSDPA service is available.

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