KR100724416B1 - Method for searching cell in mobile communication terminal - Google Patents

Abstract

The present invention relates to a cell search method of a mobile communication terminal. In particular, in a mobile communication terminal supporting multi-mode, high-speed cell reconnection is achieved by preferentially scanning neighbor cells previously registered when a serving cell is missed. The purpose is to make it possible. The present invention for this purpose is to search for adjacent cells for a predetermined time (12 seconds) if it is confirmed that the call is disconnected, and if a specific cell is not found during the discovery of the neighbor cells, a high-speed scan for the 3G / 2G network is performed a predetermined number of times / Performing a predetermined time, searching for a specific cell for the entire 3G / 2G band if a specific cell is not found even in a high-speed scan of the 3G / 2G network, and connecting a call to a specific cell found in the searching process. Characterized in that configured to perform the steps.

Description

How to search for cell in mobile terminal {METHOD FOR SEARCHING CELL IN MOBILE COMMUNICATION TERMINAL}

1 and 2 are time flow charts for explaining a call disconnection procedure in a conventional wireless communication system.

3 is a flowchart illustrating a cell search process according to an embodiment of the present invention.

The present invention relates to a mobile communication terminal, and more particularly, to a cell search method in a mobile communication terminal supporting multiple modes.

In the wireless communication system, the call is disconnected due to various causes (interference, jamming, fading, etc.) because the call is connected wirelessly. Efforts to solve the problem continue.

1 and 2 are time flow charts for explaining a call disconnection procedure in a conventional wireless communication system. 1 and 2, the conventional call disconnection procedure will be described.

While a specific wireless terminal included in the wireless communication system is in a traffic channel state, that is, while communicating with a corresponding base station of the wireless communication system through a communication channel, the wireless terminal has a forward link in a set period. The cyclic redundancy check (CRC) bit, which is a frame quality indicator of the received call channel frame, is checked.

At this time, if no error occurs in the received frame quality indicator or if the rate of the frame data can be determined, the wireless terminal determines the current frame as a good frame.

If an error occurred in the received frame quality indicator. If the data rate of the frame cannot be determined, the wireless terminal determines the current frame as a bad frame.

In addition, when initiating a forward call channel, the wireless terminal operates a fade timer, and generally 5 seconds (T5m) is executed. The fade timer is reset to 5 seconds (T5m) every two consecutive good frames.

However, in the prior art described above, 12 bad frames may occur continuously in the forward communication channel due to various causes. At this time, the radio terminal stops its own transmitter operation, and if two consecutive good frames do not come in until the fade timer expires, it determines that further communication is meaningless and disconnects the call.

On the other hand, when two good frames are received before the fade timer expires, as shown in FIG. 2, the wireless terminal determines that the currently assigned call channel is in a normal state and does not disconnect the call.

In general, any wireless terminal communicates with one base station controlling its own area without executing a separate handoff when the communication channel is in a good channel environment.

At this time, the radio terminal disconnects the call in a situation where the frames of 12 communication channels are continuously broken by the sudden change of the channel environment of the radio terminal, and the two consecutive good frames are not received until the fade timer expires.

However, if a call is dropped in the middle of a call due to a bad frame received due to a change in channel environment, the wireless terminal will continue to attempt to reconnect.

However, when the wireless terminal attempts to reconnect, the base station and the wireless terminal do not have any information on the called party, and thus, the previously defined call connection procedure must be performed from the beginning.

In other words, the wireless terminal that wants to reconnect needs to perform a procedure of connecting to the called party after accessing the base station again from the initial process, newly authenticated by the base station, and channel assignment.

Therefore, conventionally, when a cell is missed while using a wireless terminal, a cell that can be registered is always found after performing a full band scan (FBS). It has a relatively long disadvantage.

Accordingly, the present invention provides a high-speed cell reconnection by first scanning a neighboring cell previously registered when a serving cell is missed in a mobile communication terminal supporting multiple modes to improve the conventional problem. An object of the present invention is to provide a method for searching a cell of a mobile communication terminal.

In order to achieve the above object, the present invention provides a method for searching for a cell of a multi-mode mobile terminal, comprising: determining whether a call is disconnected, searching for an adjacent cell for a predetermined time when the call is disconnected; If a specific cell is not found during the neighbor cell search, searching for a specific cell at a high speed for a predetermined number of times and / or a predetermined time for the 3G / 2G-based network, and performing a fast search for the 3G / 2G-based network. If a specific cell is not found, searching for a specific cell for 3G / 2G full bands and connecting a call to a specific cell found in the searching process is performed.

That is, in the present invention, when a serving cell is missed, a predetermined number of times and / or time is determined by using information stored in the mobile communication terminal before performing a full band scan (FBS) for a specific cell search. By searching for a specific cell as much as possible, it is possible to register a cell that can be registered to a corresponding network in a short time, thereby reducing a no service time.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Technical configuration of the present invention will be described in detail in the preferred embodiment. In the preferred embodiment of the present invention will be described a number of specific details such as a specific processing flow as well as accompanying drawings to help the overall understanding of the present invention.

In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

In the embodiment of the present invention, a cell search process will be described on the assumption that a mobile communication terminal (hereinafter, referred to as a "mobile phone") supporting WCDMA and GSM misses a serving cell in a 3G-based WCDMA network.

According to an embodiment of the present invention, as shown in the operation flowchart of FIG. 3, if it is determined that the call is disconnected, searching for neighbor cells for a predetermined time (12 seconds); Performing a high-speed scan of the / 2G network for a predetermined number of times / predetermined time; searching for a specific cell for all 3G / 2G bands if a specific cell is not found even in the high-speed scan of the 3G / 2G network; It is configured to perform the step of connecting a call to a specific cell found in the process.

At this time, if the cell is missed during the WCDMA service, the cell of WCDMA or GSM stored in the mobile phone is searched for a predetermined number of times.

Referring to the process of Figure 3 in detail as follows.

First of all, if the missed serving cell is missed in the idle state of the 3G based WCDMA mode, the mobile phone first searches for a neighbor cell for a predetermined time (eg, 12 seconds).

Accordingly, when a specific cell is found in the search process, the mobile phone registers the cell in the network and proceeds with call access.

If a specific cell is not found in a neighboring cell for a predetermined time, the mobile phone that determines that the out of service performs 3G and 2G fast scans for a predetermined number of times and / or for a predetermined time, and performs 3G and 2G scans. May be repeated.

That is, after performing the 3G fast scan, the process of performing the 2G fast scan is repeatedly performed for a predetermined number of times and / or for a predetermined time. Conversely, after performing the 2G fast scan, the process of performing the 3G fast scan may be repeated.

Here, the information used for the high-speed scan is information of cells previously registered in each of the 3G and 2G networks or stored as adjacent cells, and the predetermined number and the predetermined time for the high-speed scan may be changed to suit the characteristics of the communication area. .

Accordingly, when a specific cell is found during the fast scan process, the cellular phone registers the cell in the network and proceeds with call access.

If a specific cell is not found even during neighbor cell search and 3G and / or 2G fast scan, the mobile phone performs 3G and / or 2G full band scan (FBS).

Therefore, when a specific cell is found through 3G and / or 2G full-band scan, the mobile phone registers the cell in the network and proceeds with the call connection.

In addition, in the embodiment of the present invention, the cell search operation during the call disconnection in the idle state has been described. However, even when the cell is missed in the cell PCH, cell FACH, and cell DCH states, the out of service is determined for each state. 3G and / or 2G fast scan can be used to search for specific cells.

In addition, even if the GSM network is missed, high-speed search is possible by applying the above algorithm, and a high-speed search can be performed using the same algorithm even in a phone supporting WCDMA / CDMA.

Accordingly, the present invention provides a fast search for a registerable cell by searching for a specific cell for a predetermined number of times and / or time using information stored in the mobile phone before a full-band scan (FBS) when the serving cell is missed while the mobile phone is in use. can do.

Meanwhile, although preferred embodiments of the present invention have been described, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. I can understand.

As described in detail above, the present invention stores a mobile terminal before performing a cell search for a full band when a mobile terminal supporting multiple modes (WCDMA / GSM or WCDMA / CDMA) misses a cell. By repeatedly searching for a specific cell for a predetermined number of times using the cell information, the effect of reducing the no service time by quickly searching for a registerable cell can be achieved.

Claims (4)

In the cell search method of a multi-mode mobile terminal, Determining whether the call was disconnected, Searching for an adjacent cell if the call is disconnected; Searching for a specific cell by performing a high-speed scan of a 3G / 2G network if a specific cell is not found in the neighbor cell search; And searching for a specific cell over a 3G / 2G full band if a specific cell is not found during the fast search for the 3G / 2G network. delete The method of claim 1, wherein the fast search step A 3G fast scan and a 2G fast scan are repeatedly performed a predetermined number of times. The method of claim 1, wherein the fast search step A 3G fast scan and a 2G fast scan are repeatedly performed for a predetermined time.

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