KR101177044B1 - A mobile communication terminal and the method for preventing dragging problem in the rezone of the base station having different frequency allocation without supporting the GNML - Google Patents

Abstract

The present invention relates to a lost system scan procedure of a mobile communication terminal, and more particularly, dragging occurring in a mobile communication terminal having a different frequency in a base station area that does not support G & M. The present invention relates to a mobile communication terminal having a drag problem blocking function generated when a mobile station moves to a base station area having a different frequency from a base station area that does not support GnM.

The above-mentioned mobile communication terminal includes: an RF unit for transmitting and receiving an RF signal to and from a mobile communication network; A signal measuring unit which detects and outputs a strength of a receiving base station signal of the RF unit; A control unit for outputting an execution control command of a lost system scanning procedure which is less than or equal to a reference value by comparing the strength of the base station reception signal with the signal measuring unit; And a call processing unit that performs a scheduled service interval system lost scan by a mini option during the lost system scan procedure when there is a command to execute the lost system scan procedure of the controller. It features.

GB, dragging problem, other base station (FA), lost system

Description

A mobile communication terminal and the method for preventing dragging problem in the rezone of the base station having different frequency allocation without supporting the GNML}

1 is a flowchart illustrating an example of a lost system scan procedure in the prior art;

FIG. 2 is a diagram illustrating an embodiment of a system lost scan list generated for the lost system scan procedure; FIG.

FIG. 3 is a block diagram of a mobile communication terminal having a dragging problem blocking function generated when moving from a base station area that does not support GnM according to an embodiment of the present invention to a base station area having a different frequency.

4 is a flowchart illustrating a process of a method for blocking a dragging problem of a mobile communication terminal generated when a mobile station moves from a base station area that does not support GS to a base station area having a different frequency according to an embodiment of the present invention.

DESCRIPTION OF THE RELATED ART [0002]

100: mobile communication terminal 110: RF part

120: signal measuring unit 130: control unit

140: call processing unit 150: storage unit

The present invention relates to a lost system scan (Lost System Scan) procedure of a mobile communication terminal, and more particularly, to enter a base station region having a different frequency from a base station region that does not support a general neighbor list message (GNLM). In the case where the lost system situation occurs due to missing the current service base station signal when the signal of another base station is not detected, a dragging problem is repeated which repeatedly acquires and misses the channel of the weak final service base station. The present invention relates to a mobile communication terminal having a dragging problem blocking function that occurs when a mobile station moves to a base station area having a different frequency from a base station area that does not support GS.

In general, CDMA mobile communication systems such as IS-95 A, B, C, and IS2000 divide a service area into a plurality of cells, and then install a base station for each area so that the base station is included in the corresponding cell area. It is configured to provide a mobile communication service to the mobile communication terminal. In order to support the mobility of the subscriber mobile communication terminal, the handoff (hand off or hand over) to ensure service continuity by registering the location of the mobile communication terminal so that the mobile communication service can be continuously provided even when the cell moves. Perform

 In the handoff method as described above, a handoff is performed between a traffic handoff performed by a control message of a base station in a state of providing a mobile communication service and a heterogeneous network having a different frequency (FA). There is an idle handoff performed by the mobile communication terminal itself without the control message of the base station so that the mobile communication service can be provided by the mobile communication service.

The traffic handoff described above includes soft handoff, softer handoff, hard handoff, and the like.

During such traffic handoff, the soft handoff is a handoff that moves to the services of the ingress base station after receiving the signals of the serving base station and the ingress base station at the border area when both base stations are configured to use the same frequency. To perform.

Softer handoff is performed by a swap process of receiving base station signals of three cells at the same time, selecting a base station signal of a cell to be entered, and discarding one signal.

The hard handoff is a hard handoff between frequency allocations performed with a pilot beacon (dummy pilot) transmitter and a software method instead of a pilot beacon. A common FA scheme (or DAHO: Data Assisted Handoff) for performing hard handoff, and a hard handoff between exchanges (MSCs) performed when the exchanges associated with each base station are different.

The idle handoff described above is performed by the mobile communication terminal in a call waiting state, and the mobile communication terminal compares Ec / Io with an adjacent cell among the received signals and switches to a base station of a sufficiently large size. If it is passed, it downloads various messages from the call channel of the new cell and becomes the indication state of the base station so that the mobile communication service can be provided.

As described above, the idle handoff is performed by a neighbor list message (NLM) transmitted by a base station to a mobile communication terminal to inform neighbor PN_offset in order to prepare for handoff to a neighbor base station again. It is. The mobile communication terminal receiving the neighbor base station information by the NLM performs handoff after the mobile communication terminal detects the neighbor base station signal by itself and determines whether to perform the handoff without receiving any message from the base station for handoff. Done. At this time, the mobile communication terminal uses a base station set of an Active Set, a Neighbor Set, and a Remaining Sets in a handoff procedure.

The idle handoff procedure described above will be described in more detail. The mobile communication terminal has a strength of a pilot channel allocated to base station sets received by a neighbor list message (NLM) in an idle state. / Io). In this idle state, the mobile communication terminal can receive messages, and enters a state capable of transmitting and receiving a call, performing a registration procedure, and commencing message transmission. In this state, the mobile communication terminal sets the transmission rate of the code channel and the paging channel data and supervises the paging channel.

At this time, when the mobile communication terminal moves to an area of another adjacent base station or moves to another sector of the current base station, the quality of the received signal from the current base station is degraded and the quality of the received signal from the neighboring base station or sector is improved. The communication terminal performs a handoff to the neighbor base station. In this procedure, the signal detection (channel scan) of the adjacent base station is performed by using the mobile communication system information included in the NLM provided by the previous service base station as described above.

In addition, the above-described idle handoff may be performed in a heterogeneous system having different frequencies FA. For the idle handoff procedure by the heterogeneous system having different frequencies (FA), the base station uses different frequencies (FA) by the GNLM (General Neighbor List Message) that provides neighbor base station information having different frequencies (FA). Providing neighbor base station information having a to a mobile communication terminal. That is, the above-described GNLM is a neighbor base station of another operator's network using different frequencies as the aforementioned neighbor list message (NLM) is used as a message for providing information about neighbor BSs. Provide information.

If the quality of the base station signal of the current service providing frequency (FA) is less than the reference value, the mobile communication terminal scans the base station channel using another frequency provided by the GNLM without causing a system loss situation. After the base station channel of the mobile communication system having a different frequency (FA) is searched, idle handoff can be performed.

However, when a mobile communication terminal moves from a base station area not supporting GNLM as described above to a base station area having a different frequency (FA), the mobile station does not have information of a base station to enter and thus does not detect a signal of a new base station. The system lost situation occurs by missing the signal of the serving base station currently serving. At this time, the mobile terminal performs a Lost System Scan procedure to perform a Same Geographic Entries (GEO) and Most Recently Used Entries (MRU) list included in the base station-provided NLM information. Provide a new mobile communication service by obtaining a channel by searching for base station signals and neighbor BS signals having different frequencies by scanning the channels of the < RTI ID = 0.0 > PRL < / RTI > Preferred Roaming List (PRL). It works to receive.

FIG. 1 is a flowchart illustrating an example of a lost system scan procedure in the prior art. Referring to FIG. 1, a lost system scan procedure according to the prior art will be described below.

As shown in FIG. 1, when a mobile communication terminal loses a currently serving base station signal by entering a base station area using a different frequency from a service base station area that does not support GNLM, and fails to acquire an entered base station channel. A system loss situation occurs. When a system lost situation occurs, the mobile communication terminal performs a lost system scan procedure. In this process, the mobile communication terminal first generates a system lost scan list for performing a lost system scan procedure. FIG. 2 illustrates an embodiment of the system lost scan list, wherein the system lost scan list includes the same geographic system channel list (GEO), most recently used base station channel list (MRU), and preferred roaming. It consists of a list (PRL: Preferred Roaming List) (S10).

After the system lost scan list is generated by the step S10, the final service base station scan period for scanning the channel of the service base station providing the service in the situation before the system lost occurs is set. do. As described above, the last serving base station scan period may be variously set by an operator, and in the description of FIG. 1, as an example of the last serving base station scan period, 0s, 0s, 0s, 1s, 1s, 2s, 2s, 4s, and 4s. It is assumed that the final serving base station scan period is set to 8s, 8s, 8s, 8s, ..., etc. The aforementioned final service base station scan period may be preset at the time of manufacture of the mobile communication terminal (S20).

After the final serving base station scan period is set by the step S20, it is determined whether a scheduled serving base station scan period (Scheduled Time Interval of System Lost Scan) has arrived (S30).

In the case of FIG. 1, the last serving base station scan period is 0s, 0s, 0s as 0s, 0s, 0s, 1s, 1s, 2s, 2s, 4s, 4s, 8s, 8s, 8s, 8s,. Since it is set to, the determination result of step S30 determines that the last serving base station scan period has arrived as soon as the lost scan is executed. Accordingly, the scan option is set to "full (FULL (signal of 16 dB or more))" "to perform a final lost base station scan (Scheduled Lost System Scan) three times for the channel of the final serving base station. On the other hand, when the system lost scan list scan procedure is performed after 0s during the last service base station scan period, the system lost scan list scan procedure is intercepted. The final service base station scan (Scheduled Lost System Scan) is executed in a state in which the scan option is set to "full (FULL (signal of 16 dB or more))" (S40).

Thereafter, it is determined whether the final serving base station channel is acquired by the final serving base station scan procedure in step S40 (S50).

As a result of the determination in step S50, when the channel of the final serving base station is not obtained, a system lost system scan list scan for scanning channels of systems registered in the system lost scan list is performed. At this time, the system lost scan list scan performed when the scan for the entire system lost scan list is not performed is performed by setting the option to "MINI" (signal detection of -13.5 dB or more). If the system lost scan list scan is not performed after the entire system lost scan list scan has been performed, set the scan option to "FULL (detecting a signal greater than -16dB)". After setting, the lost system scan is repeatedly performed at predetermined cycles (S60).

Next, it is determined whether the scan succeeds during the execution of the system lost scan list scan in step S60 (S70).

If the channel of the base station using a different frequency is acquired by the system lost scan list scan as a result of the determination in step S70, the mobile communication service is provided by registering to the base station system having a new frequency by performing an initial service procedure (S80). ).

On the contrary, if the channel fails to acquire the channel as a result of the determination in step S70, the process moves back to step S30 to repeat the lost system scan procedure until the acquisition of the effective channel occurs.

The conventional lost system scan procedure as described above is configured to perform the final service base station scan by the "FULL" option for each last service base station scan period between the system lost scan list scan procedures as in the above-described S40 procedure. It is.

Therefore, if the scan of the channel of the final serving base station succeeds as a result of the determination of the process S50 after the process of S40 described above, the channel of the final serving base station is acquired. The signal may cause the mobile terminal to miss its page message, or as soon as the traffic channel operation starts, the call is dropped due to the increase of bad frames. System loss situation. When the system lost situation occurs, the mobile communication terminal performs the system lost scan procedure according to the procedure shown in FIG. 1 described above, and performs the final service base station scan procedure again to obtain and lose the final service base station channel. The process is repeatedly executed, which is called a dragging problem (S90).

When a system loss occurs in a mobile communication terminal in a number of Nortel System and IS95A networks in North America that do not support GNLM, the last service base station in the boundary area is performed as a lost system scan procedure is performed. As the procedure of repeatedly catching and missing a weak signal is repeatedly performed, a mobile communication system having a different frequency fails to perform a system registration procedure in a timely manner and thus fails to receive a proper mobile communication service in a timely manner.

In addition, the dragging problem described above has a high sensitivity of the RF receiver of the mobile communication terminal, in particular, a sensitivity capable of receiving a signal far farther than a cell radius designed in consideration of the sensitivity of a general mobile communication terminal. In the case of devices such as vehicle-mounted telematics using an external antenna having a longer generation occurs, the problem becomes more serious, such as the reception performance is lower than that of a general mobile communication terminal.

Accordingly, the present invention is to solve the above-mentioned problems in the prior art, when entering the base station of the mobile communication system using a different frequency in the base station area that does not support GNLM is not performed in time In the lost system scan procedure performed by the system lost situation that occurs, the final service base station is performed by performing the periodic final service base station scan process performed by the “FULL” option by the “MINI” option. A base station having a different frequency in the base station area that does not support GnM to prevent the dragging problem in the lost system procedure by preventing the scan of the base station channel of the active set detected as a weak signal including Drag that occurs when moving to an area To provide a mobile communication terminal and a method having a problem prevention for that purpose.

In order to achieve the above object, a mobile communication terminal having a dragging problem blocking function generated when moving from a base station area not supporting GS of the present invention to a base station area having a different frequency, the mobile communication network and RF (RF) signal RF (RF) unit for transmitting and receiving; A signal measuring unit which detects and outputs a strength of a receiving base station signal of the RF unit; A control unit for outputting an execution control command of a lost system scan procedure when the signal measuring unit compares the strength of the base station received signal with a reference value or less; If there is a command to execute the lost system scan procedure of the control unit, a system lost scan list is generated, a period of the last scheduled base station scan (scheduled time interval system lost scan), and a total of the system lost scan list And a call processor for performing the lost system scan procedure after performing the lost system scan setting for setting the last service base station scan option to MINI when the scan is not performed.

The call processing unit sets the last service base station scan option to “MINI” when a scan for the entire system lost scan list has not been performed, and after at least one scan has been performed for the entire system lost scan list. Is characterized in that it operates to set to "FULL". This is for receiving a signal from the final base station system again when there is no frequency channel of another operator's network using a different frequency in a dragging problem occurrence area.

The call processor may perform system registration with a mobile communication terminal having the base station channel when acquiring a base station channel in a lost system scan procedure based on the system lost scan list.

The mobile communication terminal may further include a storage unit for storing the same area system channel list received by the controller from the base station, a preferred roaming list, and a recently accessed base station channel list.

In order to achieve the above object, a method of preventing dragging problems of a mobile communication terminal generated when moving from a base station area not supporting GnM of the present invention to a base station area having a different frequency, in the lost system scan procedure of the mobile communication terminal, Generation of a system lost scan list for a lost system scan procedure of the mobile communication terminal, a setting of a period of a final service base station scan, and a system lost scan list A lost system scan setting process of performing a lost system scan setting including setting of a final service base station scan option for setting a final service base station scan option to MINI when a full scan is not performed; A lost system scan executing process of executing a lost system scan including a system lost scan list scan and the last serving base station scan according to the setting of the lost system scan setting process; And a final service base station scan process of executing a final service base station scan by setting a MINI option when a final service base station scan period arrives during the lost system scan execution process.

In the above-described process, the system lost scan list is divided into the same geographic system channel list (GEO), the most recently used base station channel list (MRU), and the preferred roaming list (PRL). It is characterized in that the configuration.

The option of the last service base station scan in the lost system scan setup process is set to "MINI" when the last service base station scan when the scan for the entire system lost scan list is not performed, and the entire system lost scan list. The last serving base station scan after the at least one scan has been performed is characterized by being set to "FULL." This is to allow the channel of the final base station system to be acquired again when there is no frequency channel of another operator's network using a different frequency in the dragging problem occurrence region as in the operation of the call processor. .

The process of executing a lost system scan may further include a system registration process of registering a channel of a lost result of the system lost scan list scan with a mobile communication system of a corresponding channel.

The final service base station scan execution process may further include registering a final service base station system that registers with the last service base station system when the final service base station channel is searched by the last service base station scan.

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

FIG. 3 is a block diagram of a mobile communication terminal having a dragging problem blocking function generated when moving from a base station area that does not support GS to a base station area having a different frequency (FA) according to an embodiment of the present invention.

As shown in FIG. 3, the mobile communication terminal 100 according to an exemplary embodiment of the present invention receives an RF unit 110 for transmitting and receiving an RF signal to and from the mobile communication network. A signal measuring unit 120 for detecting the strength of the base station transmission signal (pilot signal) among the received signals, and a control unit 130 for controlling the execution of the lost system scan by comparing the signal measurement value for the base station transmission signal with a reference value. ), When a lost system scan control command is input from the controller 130, generation of a system lost scan list, a setting of a period of a final service base station scan, and a system lost Includes setting the last service base station scan option that sets the last service base station scan option to MINI when no scan is performed for the entire scan list. A call processing unit 140 and a storage unit 150 for performing the lost system scan procedure after performing the lost system scan setup are provided. In addition, as in the prior art, a voice service service and an audio signal of a user are provided. It includes a call function for outputting a display unit, a display unit for displaying the driving state of the mobile communication terminal, a key input unit for receiving a user control command.

Each configuration of the mobile communication terminal 100 according to an embodiment of the present invention described above will be described in more detail as follows.

The RF unit 110 converts the voice or packet data signal generated by the controller 130 into an analog baseband signal and then increases the frequency according to control information such as a transmission output strength control signal and frequency information of the controller 130. The adjustment is performed to generate the RF signal and then sent to the air through the antenna. In addition, the signal received from the base station of the mobile communication network performs frequency down adjustment to convert to the baseband signal, and then converted to a digital signal and input to the controller 130.

The signal measuring unit 120 demodulates a base station pilot signal among the received signals of the RF unit 110 to calculate and output a signal strength (Ec / Io, etc.) from the demodulated signal.

The controller 130 controls the functions of the mobile communication terminal and controls voice and packet data services. In addition, the controller 130 generates a control message including pilot channel data of the mobile communication terminal 100 and outputs it to the RF unit 110. The control unit 130 demodulates message signals including a neighbor list message (NLM) received through the RF unit 110, and then decodes SID, NID, Home information, roaming information, and system information. Demodulate and store in the storage unit 150. In addition, when comparing the measured value of the base station signal (base station pilot signal) calculated and input from the signal measuring unit 120 with the reference value, and below the reference value, the traffic handoff or idle handoff Run the procedure. In this case, when the output signal value is not detected by the signal measuring unit 120, the controller 120 determines a system loss to perform a lost system scan procedure to the call processor 140. Output

The call processor 140 performs a traffic handoff or idle handoff procedure according to a control command of the controller 130 in cooperation with the signal measuring unit 120. At this time, the traffic handoff procedure may be performed by the handoff procedure as described in the prior art, such as soft handoff, softer handoff, inter-frequency hard handoff, and the like.

When the mobile communication terminal enters the base station area of the mobile communication system having a different frequency, the mobile terminal does not have the base station information having the different frequency by the idle handoff procedure, and thus the base station channel of the other mobile communication system having the different frequency cannot be obtained. A system loss occurs that misses the last serving base station signal. In this case, the call processing unit 140 may store the same local system channel list (GEO), most recently used base station channel list (MRU), and a preferred roaming list (PRL). The system lost scan list is generated using the (or the like), the period and the option for the final lost base station scan are set, and then the lost system scan is performed.

At this time, the characteristics of the present invention, when setting the period and options for the last service station scan (Scheduled Lost System Scan), the last service base station scan option when the scan of the entire system lost scan list is not performed Is set to MINI. The final serving base station scan option is set to FULL after the scan of the entire system lost scan list is performed one or more times.

The above-mentioned MINI option is set to scan only base station channel signals with signal strength of -13.5 dB or more, and the FULL option only scans for base station channel signals with signal strength of -16 dB or more. It is common to set it to perform However, the scan options described above may be changed according to the network designer.

That is, the call processor 140 uses the system lost scan list to scan the system lost scan list and the last service base station scan period and options when a system lost occurs and receives a lost system scan control command from the controller 130. Perform a lost system scan including a final serving base station scan. In this case, the last scheduled base station scan performed when a scan for the entire system lost scan list is not performed is performed with the option set to MINI, and the scan is performed for the entire system lost scan list. After the scan is performed one or more times, the last serving base station scan is performed with the option set to FULL.

Next, the storage unit 150 stores system information, user input information, and the like of the mobile communication terminal. In particular, the same geographic system channel list (GEO: Same Geographic Entries) included in the message data transmitted from the base station, And the most recently used base station channel list (MRU) according to the access storage log information of the mobile communication terminal, the preferred roaming list (PRL) registered at the time of manufacture of the mobile communication terminal, and the like. Save necessary parameter information. The information includes parameter information such as system ID (SID), network ID (NID), home network information, roaming network information, and channel list.

4 is a flowchart illustrating a process of blocking a dragging problem of a mobile communication terminal generated when a mobile station moves to a base station region having a different frequency from a base station region that does not support GRN according to an embodiment of the present invention. In the case of FIG. 4, the final case when the scan of the entire system lost scan list is not performed as 0s, 1s, 1s, 2s, 2s, 4s, 4s, 8s, 8s, 8s, 8s,. Assume that the serving base station scan period is set to 0s.

Hereinafter, referring to FIGS. 3 and 4, a process of blocking a dragging problem of a mobile communication terminal generated when a mobile station moves to a base station area having a different frequency from a base station area that does not support GEM according to an embodiment of the present invention will be described. Is as follows.

As shown in FIG. 4, when the mobile communication terminal 100 enters a base station area using a different frequency from a service base station area that does not support GNLM, a signal of a current service base station is not obtained when a new base station channel signal is not obtained. Missing this will cause System Lost. As described above, when a system lost situation occurs in the mobile communication terminal 100, the mobile communication terminal 100 generates a system lost scan list. The system lost scan list includes a Geographic System Channel List (GEO), Most Recently Used Entries (MRU), and a Preferred Roaming List (PRL). As shown in (S110).

After the system lost scan list is generated by the step S110, the final service base station scan period (Scheduled Time Interval of System Lost Scan) is set. Scheduled Time Interval of System Lost Scan may be variously set according to the operator. As described above, 0s, 1s, 1s, 2s, 2s, 4s, 4s, 8s, 8s, 8s, 8s, .... At this time, the last service base station scan option is set to MINI for the last scheduled base station scan performed when a scan for the entire system lost scan list is not performed, and the system lost scan is performed. The final serving base station scan (Scheduled Lost System Scan) after the scan of the entire list is performed at least once is set to a pull (FTLL). The scan options described above include the MINI and FULL options. The MINI option scans only base station signals of -13.5 dB or more, and the FULL option of -16 dB or more base stations. Scanning is performed only on the signals, and the present invention is not limited thereto and may be changed according to the network designer as described above (S120).

After the final serving base station scan period is set by the step S120, it is determined whether a scheduled serving base station scan period (Scheduled Time Interval of System Lost Scan) has arrived (S130).

As a result of the determination in step S130, when the last scheduled base station scan (Scheduled Time Interval of System Lost Scan) cycle arrives in step S120, the final scheduled service interval scan (Scheduled Time Interval of System Lost Scan) is executed according to the option set in step S120. Otherwise, the system lost scan list scan using the system lost scan list is performed.

In this case, as described above, in the case of FIG. 4, the final serving base station scan period is 0s as 0s, 1s, 1s, 2s, 2s, 4s, 4s, 8s, 8s, 8s, 8s,... Since it is assumed that it is set, it is determined that the last serving base station scan period has arrived as soon as the lost system scan procedure is executed as a result of the determination of step S130. Therefore, since the scan of the entire channel of the system lost scan list has not been performed after the S130 process, the scan of the final serving base station is set by setting the scan option to “MINI” (signal detection of -13.5 dB or more). Lost System Scan) is performed. However, the scan option is set to FULL (detecting a signal of -16 dB or more) for the final scheduled base station scan after the scan of the entire system lost scan list is performed at least once (S140).

Thereafter, it is determined whether the final service base station channel is acquired by the final service base station scan procedure of step S140 (S150).

When the final service base station channel is found by the final service base station scan procedure as a result of the determination in step S150, after acquiring the channel of the final service base station system, the mobile station service is provided by performing registration with the final service base station system. This option is set to mini for the last service base station scan when no scan is performed for the entire system lost scan list, or FULL if the scan for the entire system lost scan list has been performed more than once. The final service base station channel obtained in a situation where the entire system lost scan list has not been performed at all is likely to be an effective channel having a valid signal strength, and the entire system lost scan list is performed at least once. If the final service base station scan is performed afterwards, it may be determined that there is no base station channel having a different frequency FA of valid signal strength in the region where the mobile communication terminal is currently located (S180).

On the contrary, if the channel is not found by the final service base station scan procedure as a result of the step S150, the system lost scan list scan is performed to scan the channels of all base station systems listed in the system lost scan list generated in step S120. The system lost scan list scan described above is performed by the MINI option in the case of the first system lost scan list scan in which a scan for the entire system lost scan list has not been performed at all, as in the prior art. In the case of the system lost scan list scan after the scan of the entire scan list is performed more than once, set the Full (FULL (detection of signal more than -16dB)) option and perform the system lost scan list scan at regular intervals. (S160).

Next, it is determined whether a valid channel has been found as a result of performing the system lost scan list scan in step S160 (S170).

If a valid channel is found as a result of the determination in step S170, after acquiring the searched channel of the base station system having the corresponding channel, a system registration procedure is performed to receive a mobile communication service by the corresponding base station system (S180).

On the contrary, if the effective channel is not found as a result of the determination in S170, the process moves back to S130 and then the system lost scan list scan by the system lost scan list generated in S120, the last service base station scan period generated in S120, and The optional final service base station scan procedure is repeated until there is a search for a valid channel.

According to the present invention described above, a scan of the entire system lost scan list is not performed from the final lost base station scan in the process of performing a lost system scan after a system loss occurs. When doing so, set the scan option to MINI to avoid capturing the weak end service base station signal. Therefore, the final service base station scan procedure does not perform the final service base station scan on an invalid signal having a signal less than or equal to the mini (-13.5 dB or less) option in the final service base station scan procedure when a scan of the entire system lost scan list is not performed. It is possible to prevent the dragging problem of repeatedly catching and missing the weak end service base station signal in the system scan procedure.

In addition, the present invention described above uses a full (-16 dB or less) option to perform another scan in the final service base station scan procedure after the last service base station scan when the scan of the entire system lost scan list is not performed. When the channel of the base station system to be used does not exist, after receiving the final service base station signal and performing system registration, the mobile communication service can be provided.

Therefore, in the present invention, when the channel of the last serving base station is found in the final serving base station scan when the scan of the entire system lost scan list is not performed, and the final serving base station channel is found in the subsequent serving base station scan, the final serving base station By performing registration with the system, even if the base station channel of the mobile communication system having a different frequency does not exist, the system can be provided with a mobile communication service after ending the lost situation.

The present invention described above is performed when a system lost scan procedure is performed due to a failure of an appropriate idle handoff when moving from a base station not supporting a general neighbor list message (GNLM) to another frequency (FA) region. In order to prevent the scan of the weak last service base station channel signal that is not valid, the final service base station scan when the scan of the entire system lost scan list is not performed is performed by the MINI option. By doing so, it is possible to block the Dragging Problem.

In addition, the present invention described above provides an additional effect of improving the reception performance of the mobile communication terminals by blocking the dragging problem as described above.

Claims (9)

An RF unit for transmitting and receiving an RF signal to and from the mobile communication network; A signal measuring unit which detects and outputs a strength of a receiving base station signal of the RF unit; A control unit for outputting an execution control command of a lost system scan procedure when the signal measuring unit compares the strength of the base station received signal with a reference value or less; If there is a command to execute the lost system scan procedure of the controller, generation of a system lost scan list, a setting of a schedule of a last service base station scan (Scheduled Time interval System Lost Scan), and the entire system lost scan list are performed. And a call processor configured to perform the lost system scan procedure after performing the lost system scan setting for setting the last service base station scan option to MINI when no scan is performed. A mobile communication terminal having a dragging problem blocking function generated when moving from a base station area not supporting LM to a base station area having a different frequency. The method of claim 1, wherein the call processing unit, The last serving base station scan option is set to "MINI" when a scan for the entire system lost scan list has not been performed, and after the scan for the entire system lost scan list has been performed one or more times, A mobile communication terminal having a dragging problem blocking function generated when a mobile station moves to a base station area having a different frequency from a base station area that does not support GS, characterized in that it is set to "FULL". The method according to claim 2, wherein the call processing unit performs a system registration to the mobile communication terminal having the base station channel when the base station channel is acquired in the lost system scan procedure by the system lost scan list. A mobile communication terminal having a dragging problem blocking function generated when moving from an unsupported base station area to a base station area having a different frequency. The base station area having a different frequency in the base station area that does not support GS, characterized in that the system lost scan list is composed of the same area system channel list, the preferred roaming list and the recently accessed base station channel list. A mobile communication terminal having a function of blocking a dragging problem occurring when moving to a mobile station. In the lost system scan procedure of the mobile communication terminal, Generation of a system lost scan list for a lost system scan procedure of the mobile communication terminal, a setting of a period of a final service base station scan, and a system lost scan list A lost system scan setting process of performing a lost system scan setting including setting of a final service base station scan option for setting a final service base station scan option to MINI when a full scan is not performed; A lost system scan executing process of executing a lost system scan including a system lost scan list scan and the last serving base station scan according to the setting of the lost system scan setting process; When the last service base station scan cycle arrives during the lost system scan execution process, the last service base station scan process for executing a final service base station scan by setting a Mini option (MINI); does not support A method for blocking dragging problems of a mobile communication terminal generated when a mobile station moves from a base station area to a base station area having a different frequency. The method of claim 5, wherein the option of the last serving base station scan of the lost system scan setup process, The final service base station scan when the scan of the entire system lost scan list is not performed is set to "MINI", and the last service base station after the scan of the entire system lost scan list has been performed at least once. Scanning is a method of preventing a dragging problem of a mobile communication terminal that occurs when moving from the base station area that does not support GMB to the base station area having a different frequency, characterized in that set to "FULL". The method of claim 5, wherein the lost system scan execution process, Blocking the dragging problem of the mobile communication terminal generated when moving to the base station area, characterized in that it further comprises a system registration process for registering the channel as a result of the scan by the system lost scan list scan to the mobile communication system of the channel; Way. The method of claim 5, wherein the last serving base station scan process, Blocking the dragging problem of the mobile communication terminal generated when moving to the base station area, characterized in that it further comprises a; registering the final service base station system when the last service base station channel is searched by the last service base station scan; Way. 8. The movement according to any one of claims 5 to 7, wherein the system lost scan list comprises a co-located system channel list, a preferred roaming list, and a recently accessed base station channel list. How to block dragging problem in communication terminal.

Images