KR20070067400A - Method for selecting cell again in wireless telecommunication terminal - Google Patents

Abstract

A method for re-selecting a cell in a mobile terminal is provided to maintain a connection with a current cell when a mobile terminal enters a weak field and an attenuation reference value exceeds the first threshold value, check a reception level if the attenuation reference value does not exceed the first threshold value, maintain the connection with the current cell if the reception level exceeds the second threshold value, and select a new cell when the reception level does not exceed the second threshold value. When a mobile terminal connected with a cell enters a weak field, it is checked whether an attenuation reference value exceeds a threshold value(201,202). When the attenuation reference value exceeds the first threshold value, the mobile terminal maintains its connection with the cell(203). If the attenuation reference value does not exceed the first threshold value, it is checked whether a signal reception level from a base station exceeds the second threshold value(204). When the signal reception level does not exceed the second threshold value, a new cell is searched and re-selected(205).

Description

Method for selecting cell again in wireless telecommunication terminal

1 is a configuration diagram of an embodiment of a wireless communication terminal to which the present invention is applied;

2 is a flowchart illustrating a cell reselection method in a wireless communication terminal according to the present invention.

* Explanation of symbols for the main parts of the drawings

101: duplexer 102: receiver

103: transmitting unit 104: audio unit

105: key input unit 106: display unit

107: interface unit 108: storage unit

109: control unit 110: camera unit

The present invention relates to a cell reselection method in a wireless communication terminal, and more particularly, to maintain connection with a current cell when the attenuation reference value exceeds the first threshold as the weak electric field is entered, and the attenuation reference value is the first threshold value. If not exceeded, the reception level is checked and if the second threshold is exceeded, the connection with the current cell is maintained. If the second threshold is not exceeded, a new cell is selected, thereby eliminating unnecessary cell reselection, thereby reducing power waste. The present invention relates to a cell reselection method in a wireless communication terminal.

In the present invention, the wireless communication terminal is a mobile communication terminal, a personal communication service (PCS) terminal, a personal digital assistant (PDA), a smart phone, a next generation mobile communication (IMT-2000) terminal, a wireless LAN terminal, and the like through wireless communication, Refers to a portable wireless communication terminal capable of transmitting and receiving text and image data.

In addition, in an embodiment of the present invention will be described as an example of a Global System for Mobile communication (GMS) terminal.

In the weak field region where the base station signal is weak, the wireless communication terminal performs the task of searching for a new network according to the current GSM algorithm, although the base station signal can be sufficiently received by the cell reselection parameters of the base station.

The GSM standard cell selection / reselection algorithm is designed to perform cell selection / reselection in a wireless communication terminal according to base station configuration information without considering the situation of the wireless communication terminal.

If the wireless terminal is located in an area where the base station signal is weak, if the cell selection / reselection is performed according to the GSM standard, the wireless terminal can receive base station BCCH information sufficiently in the current cell and transmit radio waves. In turn, the wireless terminal continues to find a new cell.

Accordingly, there is a demand for a method of performing cell selection / reselection in consideration of the ability to sufficiently receive a base station signal when the wireless communication terminal is located in a weak electric field and to transmit its own signal to the base station.

Generally, after receiving a signal from a base station, the wireless terminal finds the most suitable cell and periodically updates the base station information, decodes a paging channel to respond to a request for a call or data, and idle mode in a service request waiting state. Stay on. At this time, the wireless communication terminal periodically updates the paging channel and base station information to reduce power consumption.

At this time, in order to find the most suitable cell, cell selection / calculation is performed by calculating a reference value by a defined algorithm using parameters used for cell selection / reselection received from the base station, reception power of the base station signal, and transmission maximum power. Determine reselection.

That is, when the base station signal becomes weak in the idle mode, the C1 value, which is the signal attenuation reference value below, becomes smaller than 0, and reselection is performed. At this time, if the reselection fails, the cell selection algorithm starts again.

C1 = receive radio wave strength-RXLEV_ACCESS_MIN-max (0, MS_TXPWR_MAX_CCH-transmit maximum power)

* Received radio wave strength: signal strength of base station received from wireless communication terminal

* RXLEV_ACCESS_MIN: A parameter transmitted from the base station. The wireless communication terminal must receive more than this parameter.

* MS_TXPWR_MAX_CCH: This parameter is transmitted from the base station. The radio communication terminal is limited to using more power when transmitting to the base station.

* Maximum transmit power: means the maximum power that can be transmitted from the wireless communication terminal.

Here, referring to the cell reselection method of the conventional wireless communication terminal, first, the power-on wireless communication terminal uses a network code (Network Code) for a previously registered network to establish a Public Land Mobile Network (PLMN). Choose.

Thereafter, the network code of the selected PLMN and the network code of the signal received from the base station are compared.

Subsequently, if the network code is the same and the condition of the signal attenuation criterion C1 value is satisfied, the registration procedure is performed and stays in the idle state in the idle mode.

Thereafter, the wireless communication terminal periodically calculates a reference for the serving cell signal and maintains an idle mode after reselecting a cell when the C1 value is less than 0 or the signal quality of the neighboring cell is better than the signal quality of the serving cell. .

In this case, when the voice call is set, it is determined whether to return to the previous cell or move to the new cell by reselection when the call is terminated while maintaining the call by transitioning to the connected mode. This is determined by the reason code that was revoked when the call was terminated.

In the conventional cell reselection method of the conventional wireless communication terminal, the signal quality is reduced when the signal attenuation reference value C1 is less than 0, although the base station BCCH information can be sufficiently received in the current cell and the radio wave can be transmitted. Find a good cell and reselect it.

Due to the cell reselection, the general service cannot be provided to the user, and if the cell reselection fails, the current cell is also lost. Therefore, the network needs to be found again from the beginning, thus consuming more power. have. In the worst case, the wireless communication terminal may continuously perform the cell reselection step, in which the waste of unnecessary power is much worse.

The present invention has been proposed to solve the above-mentioned problems. As the weak electric field enters, the present invention maintains the connection with the current cell when the attenuation reference value exceeds the first threshold, and when the attenuation reference value does not exceed the first threshold, the reception level is increased. By checking and maintaining a connection with the current cell when the second threshold is exceeded, and selecting a new cell when the second threshold is not exceeded, unnecessary radio frequency reselection is not performed to reduce power waste. The purpose is to provide a cell reselection method.

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.

In the method of the present invention for achieving the above object, in the method of cell reselection in a wireless communication terminal, the attenuation reference value C1 exceeds a first threshold value as a wireless communication terminal connected to a cell enters a weak electric field. Confirming that; Maintaining a connection with the cell if the attenuation reference value exceeds a first threshold as a result of the checking; Determining that the signal reception level from the base station exceeds the second threshold if the attenuation reference value does not exceed the first threshold; Maintaining a connection with the cell if the signal reception level exceeds a second threshold as a result of the determination; And searching and reselecting a new cell if the signal reception level does not exceed the second threshold.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an embodiment of a wireless communication terminal to which the present invention is applied.

As shown in FIG. 1, the wireless communication terminal to which the present invention is applied transmits a signal received from the transmitter 103 to a base station through an antenna or transmits a signal received from the base station through an antenna to the receiver 102. A duplexer 101, a receiver 102 for receiving a signal through the duplexer 101, and a transmitter for transmitting a signal modulated by the audio unit 104 to the duplexer 101 through an interface unit 107. (103) modulates the voice signal input through the microphone into a digital signal and transmits it to the transmitting unit 103 through the interface unit 107, and demodulates the digital signal received through the receiving unit 102 to output the voice signal through the speaker. Audio unit 104 or various function keys and numeric keys for outputting a ring signal generated from a base station or a base station through a speaker. Key input unit 105, input telephone number, caller's telephone number, short message, and display unit 106 for outputting a message indicating that the current cell is the home network, and control unit 109 And an interface unit 107 for interfacing data input and output between the components and surrounding components, a camera unit 110 for capturing an image, a storage unit 108 for storing an image photographed by the camera unit 110, As the attenuation reference value exceeds the threshold as the weak electric field enters, the connection with the current cell is maintained.If the attenuation reference value does not exceed the threshold, the connection level is checked. If the reception level is exceeded, the connection with the current cell is maintained. And a control unit 109 for controlling the respective transport elements to select a new cell if the level is not exceeded.

2 is a flowchart illustrating a cell reselection method in a wireless communication terminal according to the present invention.

First, as the wireless communication terminal connected to the cell enters the weak electric field, it is checked whether the attenuation reference value C1 exceeds the threshold (201 and 202).

As a result of the check 202, if the attenuation reference value exceeds the first threshold (eg 0), the connection with the cell is maintained (203).

On the other hand, if it is determined that the attenuation reference value does not exceed the first threshold, the determination result 202 determines whether the signal reception level from the base station exceeds the second threshold (eg, 0) (204).

As a result of the determination 204, if the signal reception level exceeds the second threshold, the connection with the cell is maintained (203).

On the other hand, if the determination result 204, the signal reception level does not exceed the second threshold, a new cell is searched for and reselected (205). In this case, when the current cell is a home network, the cell may be reselected according to a cell selection signal from the user.

As described above, the method of the present invention 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.

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.

As described above, the present invention maintains the connection with the current cell when the attenuation reference value exceeds the first threshold as the weak electric field is entered, and checks the reception level when the attenuation reference value does not exceed the first threshold. If it exceeds, maintaining the connection with the current cell and selecting a new cell if the second threshold is not exceeded, there is an effect that the unnecessary cell selection process is not performed to reduce power waste.

Claims (3)

In the cell reselection method in a wireless communication terminal, Checking whether the attenuation reference value (C1) exceeds a threshold value as the wireless communication terminal connected to the cell enters the weak electric field; Maintaining a connection with the cell if the attenuation reference value exceeds a first threshold as a result of the checking; Determining that the signal reception level from the base station exceeds the second threshold if the attenuation reference value does not exceed the first threshold; Maintaining a connection with the cell if the signal reception level exceeds a second threshold as a result of the determination; And Searching and reselecting a new cell if the signal reception level does not exceed the second threshold as a result of the determination; Cell reselection method in a wireless communication terminal comprising a. The method of claim 1, If the cell (cell currently connected) is a home network, A cell reselection method in a wireless communication terminal, characterized in that the cell is reselected according to a cell selection signal from a user. The method according to claim 1 or 2, The first threshold and the second threshold, A cell reselection method of a wireless communication terminal, characterized in that 0.

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