KR100676230B1 - Method and apparatus for providing idle handover - Google Patents

Abstract

The present invention relates to a method and apparatus for performing a standby handover from a WCDMA system to a synchronous system, and more particularly, to a method and apparatus for performing a handover when a mobile terminal transitions from a WCDMA system to a synchronous system in a standby state. The method includes receiving a standby handover condition from a WCDMA system in a WCDMA mode, determining whether the signal strength sent from the WCDMA system satisfies the standby handover condition, and if the determination result satisfies the standby handover condition, Activating, receiving a pilot signal and a synchronous signal from the synchronous system using the synchronous modem, entering a standby state, and turning off the WCDMA modem to convert from the WCDMA mode to the synchronous mode.

WCDMA system, synchronous

Description

Method and apparatus for providing idle handover             

1 is a view for explaining a standby handover procedure according to the prior art.

2 is a flowchart schematically illustrating a procedure for performing a standby handover according to an embodiment of the present invention.

3 is a view for explaining a standby handover method according to an embodiment of the present invention.

4 is a view for explaining a process of setting a standby handover condition to a mobile terminal in a WCDMA system according to an embodiment of the present invention.

5 is a signal flow diagram illustrating a procedure for a standby handover according to an embodiment of the present invention.

6 illustrates parameters in a SIB 3 message according to one preferred embodiment of the present invention.

7 is a view for explaining parameter values indicating a standby handover condition to which RSCP is applied according to an embodiment of the present invention.

8 is a view for explaining parameter values indicating a standby handover condition to which Ec / Io is applied according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

301: WCDMA Cell

303: WCDMA Border Cell

401 UE (User Equipment)

403: Universal Terrestrial Radio Access Network (UTRAN)

The present invention relates to a method and apparatus for making a standby handover from a WCDMA system to a synchronous system, and more particularly, to a method and apparatus for handover when a mobile terminal transitions from a WCDMA system to a synchronous system in a standby state.

In general, handover (handoff) refers to changing a call path to a moved cell in order to maintain a call when the mobile terminal moves out of the cell area to another cell. The mobile terminal compares the threshold for the pilot channel strength received from the base station with the pilot channel strengths of other neighboring base stations that it continues to measure. If at some point the comparison of these measurements indicates a value that requires handover, the mobile terminal reports it to the mobile communication network and performs handoff under control of the responsible system according to the type of handoff. On the other hand, the change of the base station during the waiting for reception, i.e., the idle state, is called idle handover. Referring to FIG. 1, the procedure for performing the standby handover is as follows.

1 is a diagram illustrating a standby handover procedure according to the prior art.

Referring to FIG. 1, the horizontal axis represents the traveling direction of a mobile station (MS), and the vertical axis represents the strength (Ec / Io) of the pilot signal. When the mobile terminal moves from Cell 1 to Cell 2, the Ec / Io 101 of the pilot signal of Cell 1 gradually decreases, and the Ec / Io 103 of the pilot signal of Cell 2 gradually increases. In this case, the mobile terminal in comparison with the Ec / Io 101 of the pilot signal of Cell 1 and the Ec / Io 103 of the pilot signal of Cell 2 compares the Ec / Io 103 of the pilot signal of Cell 2 with the cell 1 of Cell 1. A standby handover to Cell 2 is performed at a point 105 that is greater than 3 dB greater than the Ec / Io 101 of the pilot signal. This standby handover is for standby handover within the same system and does not apply to standby handovers that differ from system to system, such as moving from asynchronous to synchronous systems.

The 3GPP standard, the international standard for WCDMA systems, is based on the Global System for Mobile Communication (GSM) system, the second-generation asynchronous system, and the interworking standards with the IS-95 series, which are synchronous systems, are still in progress. . On the other hand, since domestic mobile communication systems are based on synchronous systems, in order to provide convenience to users of WCDMA systems, which are difficult to establish nationwide networks in the early stages of commercial WCDMA implementations, Idle Handover or Roaming functions are implemented with existing synchronous systems. There is a need to do so.

An object of the present invention for solving the above problems is to provide a method and apparatus for performing a standby handover from a WCDMA system to a synchronous system.

Another object of the present invention is to provide a method and apparatus for optimal standby handover by adjusting parameters in an SIB 3 message received in a standby state and an internal timer of a mobile terminal.

Another object of the present invention is to provide a method and apparatus for minimizing changes in existing mobile terminals and systems, and performing standby handover that does not require a separate network construction such as a beacon.

In order to achieve the above objects, according to an aspect of the present invention, there is provided a method for performing a standby handover from the WCDMA system to the synchronous system in a mobile terminal which includes a WCDMA modem and a synchronous modem and is coupled with a WCDMA system and a synchronous system. Receiving a standby handover condition from the WCDMA system in a WCDMA mode; Determining whether the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Activating the synchronous modem when the determination result satisfies a standby handover condition; Receiving a pilot signal and a synchronization signal from the synchronous system using the synchronous modem to enter a standby state; And turning off the WCDMA modem to switch from the WCDMA mode to the synchronous mode, thereby providing a standby handover from the WCDMA system to the synchronous system.
In one preferred embodiment, the synchronous modem is a CDMA 1X modem. The standby handover condition may be received through an SIB 3 message in an idle state. In addition, the Ec / Io is characterized in that applied to the border cell (border cell). In addition, when RSCP is applied, a handover condition is satisfied when RSCP of the WCDMA system lasts more than TH_on_idle_RSCP or more than T_on_idle_RSCP. In addition, when Ec / Io is applied, a handover condition is satisfied when Ec / Io of the WCDMA system persists more than TH_on_idle_SNR or more than T_on_idle_SNR. In addition, the TH_on_idle_RSCP and T_on_idle_RSCP are each set to values set in the S _{HCS, RAT} , S _{limit, and SearchRAT} parameters in the SIB 3 message. In addition, the TH_on_idle_SNR and T_on_idle_SNR may be set to S _{HCS, RAT} , S _{limit and SearchRAT} parameters in the SIB 3 message, respectively.
According to another aspect of the present invention, there is provided a method for performing a standby handover from the WCDMA system to the synchronous system in a WCDMA modem included in a mobile terminal combined with a WCDMA system and a synchronous system. Receiving; Determining whether the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Transmitting a synchronous modem activation request signal to a control unit included in the mobile terminal when the determination result is satisfied, wherein the control unit corresponds to the synchronous modem activation request signal and includes the synchronous modem included in the mobile terminal; Activate the signal, and the synchronous modem receives a pilot signal and a synchronous signal from the synchronous system and enters a standby state; Receiving a first standby state indication signal from the controller, wherein the first standby state indication signal corresponds to a second standby state indication signal received by the controller from the synchronous modem in response to entering the standby state; ; And transmitting a terminal mode change request signal to the control unit, wherein the control unit turns off the WCDMA modem to convert the state of the mobile terminal from the WCDMA mode to the synchronous mode. It is possible to provide a method for standby handover with a synchronous system.
According to another aspect of the present invention, a method for performing a standby handover from the WCDMA system to the synchronous system in a synchronous modem included in a mobile terminal coupled with a WCDMA system and a synchronous system, the control unit included in the mobile terminal Receiving a first synchronous modem activation request signal, wherein the first synchronous modem activation request signal is an RSCP that a WCDMA modem included in the mobile terminal receives a standby handover condition from the WCDMA system and is sent from the WCDMA system; (Received Signal Code Power) and at least one signal strength of the Ec / Io signal corresponds to the second synchronous modem activation request signal transmitted to the control unit when the standby handover condition is satisfied; Activating by the first synchronous modem activation request signal; Receiving a pilot signal and a synchronization signal from the synchronous system and entering a standby state; And transmitting a first standby state indication signal to the controller when entering a standby state, wherein the controller transmits a second standby state indication signal to the WCDMA modem in response to the first standby state indication signal. And after receiving a terminal mode change request signal from the WCDMA modem, turning off the WCDMA modem to convert the state of the mobile terminal from the WCDMA mode to the synchronous mode. Can provide a way to over.
According to still another aspect of the present invention, a mobile terminal including a WCDMA modem and a synchronous modem, and having a standby handover from the WCDMA system to the synchronous system in combination with a WCDMA system and a synchronous system, the WCDMA system in a WCDMA mode. Means for receiving a standby handover condition from the network; Means for determining whether a signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Means for activating the synchronous modem when the determination result satisfies a standby handover condition; Means for receiving a pilot signal and a synchronous signal from the synchronous system using the synchronous modem to enter a standby state; And means for turning off the WCDMA modem to switch from WCDMA mode to synchronous mode.
According to another aspect of the present invention, in a WCDMA modem included in a mobile terminal combined with a WCDMA system and a synchronous system to perform a standby handover from the WCDMA system to the synchronous system, a standby handover condition is received from the WCDMA system. Means for doing so; Means for determining whether a signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Means for transmitting a synchronous modem activation request signal to a controller included in the mobile terminal when the determination result is satisfied, wherein the controller is a synchronous modem included in the mobile terminal in response to the synchronous modem activation request signal. Activate the signal, and the synchronous modem receives a pilot signal and a synchronous signal from the synchronous system and enters a standby state; Means for receiving a first standby state indication signal from the control unit, wherein the first standby state indication signal corresponds to a second standby state indication signal received by the control unit from the synchronous modem in response to entering the standby state; ; And means for transmitting a terminal mode change request signal to the control unit, wherein the control unit turns off the WCDMA modem to convert the state of the mobile terminal from the WCDMA mode to the synchronous mode. Can provide.
According to another aspect of the present invention, in a synchronous modem which is included in a mobile terminal combined with a WCDMA system and a synchronous system to perform a standby handover from the WCDMA system to the synchronous system, the first control unit includes: Means for receiving a synchronous modem activation request signal, wherein the first synchronous modem activation request signal is received by a WCDMA modem included in the mobile terminal and receives a standby handover condition from the WCDMA system, and is transmitted from the WCDMA system. Signal Code Power) and an Ec / Io signal corresponding to the second synchronous modem activation request signal transmitted to the controller when the signal strength of the at least one of the signal satisfies the standby handover condition; Means for activating by the first synchronous modem activation request signal; Means for receiving a pilot signal and a synchronization signal from the synchronous system and entering a standby state; And means for transmitting a first standby state indication signal to the controller when entering a standby state, wherein the controller transmits a second standby state indication signal to the WCDMA modem in correspondence with the first standby state indication signal. After receiving the terminal mode change request signal from the WCDMA modem, the WCDMA modem may be turned off to convert the state of the mobile terminal from the WCDMA mode to the synchronous mode.

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Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a flowchart schematically illustrating a procedure of performing a standby handover according to an exemplary embodiment of the present invention. In this case, the idle handover refers to a handover when the mobile terminal moves from the WCDMA system to the synchronous system in the standby state.

Referring to FIG. 2, first, a mobile terminal according to the present invention enters an idle state in a WCDMA mode (step 201). The mobile terminal is based on a Multi Mode Multi Band (MMMB) including a WCDMA modem and a CDMA 1X modem, and can operate in a WCDMA mode and a CDMA 1X mode. In this specification, for convenience of description, a WCDMA modem and a CDMA 1X modem will be described as an example, but a WCDMA modem means a modem supporting an asynchronous system, and a CDMA 1X modem means a modem supporting a synchronous system.

The mobile terminal receives the parameters related to the standby handover (handoff) in the standby state (step 203). In this case, the parameters represent reference values indicative of a condition of standby handover, and they are transmitted from the WCDMA system to the mobile terminal through a system information block type 3 (SIB 3) message in a standby state.

Thereafter, the mobile terminal measures the signal strength of the WCDMA system in the standby state, and determines whether the standby handover (handoff) condition by the parameter values received in step 203 is satisfied (step 205).

If the standby handover (handoff) condition is satisfied in step 203, the mobile terminal activates the CDMA 1X modem (step 207). The CDMA 1X modem attempts to enter the Idle State by receiving a pilot signal and a sync signal from the synchronous system in the activated state (step 209). If the entry into the standby state is successful in step 209, the mobile terminal performs step 211, and returns to step 205 if the entry into the standby state fails. In step 209, if the mobile terminal attempts to enter the standby state and starts the timer and fails to enter the standby state for a predetermined time, the mobile terminal may consider that the entry into the standby state has failed. In step 211, the mobile terminal turns off the WCDMA modem to switch to the CDMA 1X mode (step 211).

3 is a view for explaining a standby handover method according to an embodiment of the present invention.

Referring to Fig. 3, the standby handover (handoff) according to the present invention includes two types of handovers. That is, in a border cell 303 considering a handover to guarantee the continuity of the service of the subscriber in the shaded area of the cell 301 in the region of the WCDMA system and also the case where the subscriber moves out of the region of the WCDMA system. It includes a handover. Here, even if the subscriber moves out of the shadow area or the region of the WCDMA system, the subscriber should be included in the range of the cell 305 of the synchronous system to receive the service of the synchronous system. That is, the handover (handoff) should be basically performed in the overlapped region of WCDMA and CDMA 1X, and whether or not the overlapped region is transmitted to the mobile terminal through the WCDMA system information.

In the present invention, a handover condition is set through setting of a Radio Access Technology (RAT) LIST in a SIB 3 message according to the 3GPP standard of WCDMA, which is an asynchronous method. Handover in the WCDMA cell 301 is basically applied to the conditions of Received Signal Code Power (RSCP), handover in the border cell 303 is applied to the conditions of RSCP or Ec / Io, preferably Ec The condition of / Io may apply. In order to apply the conditions of RSCP and Ec / Io, the RAT LIST in SIB 3 is extended to 3 and transmitted to the mobile terminal. The mobile terminal receives the RAT LIST in the standby state to determine whether the border cell is present and performs handover (handoff) under a given condition from the WCDMA system.

4 is a diagram illustrating a process of setting a standby handover condition to a mobile terminal in a WCDMA system according to an embodiment of the present invention.

Referring to FIG. 4, the Universal Terrestrial Radio Access Network (UTRAN) UTRAN transmits a System Information Block Type 3 (SIB 3) message to a user equipment (401) in a standby state (step 405). Here, the UE 401 refers to a mobile terminal performing a standby handover to a WCDMA system according to the present invention as a synchronous system, and the UTRAN 403 refers to a base station (BS) and a base station controller (RNC) of a WCDMA system. Means.

The standby handover condition for implementing a standby handover from the WCDMA system to the synchronous system is set by parameter values in the SIB 3 message. The SIB 3 message is defined by the 3GPP standard and is a message that can be received when the WCDMA modem of the mobile station stays in an idle state, and includes cell selection and re-selection information. The SIB 3 message will be described in detail with reference to FIG.

5 is a signal flow diagram illustrating a procedure for performing standby handover according to an exemplary embodiment of the present invention.

5, a mobile terminal (MS) according to the present invention includes a WCDMA modem (asynchronous modem), a control unit and a CDMA 1X modem (synchronous modem), the mobile terminal in two modes of WCDMA mode and CDMA 1X mode It operates and takes precedence over WCDMA mode. In WCDMA mode, only the WCDMA modem is activated. In CDMA 1X mode, only the CDMA 1X modem is activated. The control unit controls the activation and deactivation of the WCDMA modem and the CDMA 1X modem. In the present specification, the mobile terminal is described based on MMMB (Multi Mode Multi Band), but may be designed as a 1 chip modem in the future. At this time, there is no change in the internal signal of the mobile terminal and the signal between the terminal and the system.

The standby handover procedure according to the present invention begins with the assumption that the mobile terminal is in the WCDMA mode. In the standby state, the mobile terminal receives a standby handover condition from the WCDMA system through a SIB 3 message (step 501). The standby handover condition will be described in detail with reference to FIGS. 7 and 8.

The WCDMA modem determines whether the signal strength of the WCDMA system satisfies the standby handover condition (step 502). As a result of the determination, if the wait handover condition is satisfied, the WCDMA modem transmits a CDMA 1X modem activation signal (CDMA 1X Modem On) to the control unit (step 503). The control unit transmits the received CDMA 1X modem activation signal (CDMA 1X Modem On) to the CDMA 1X modem to activate the CDMA 1X modem (step 505).

The CDMA IX modem receives pilot signals and sync signals from the CDMA IX system (synchronous system) and attempts to enter a standby state (step 507). The CDMA 1X modem entering the standby state transmits the result to the idle state indication signal (Idle State Indication) to the controller (step 509), and the controller transmits the result to the WCDMA modem (step 511). At this time, the mobile terminal sets a timer (Taw) for Idle State Indication, if it does not receive the Idle State Indication before the timer expires, deactivates the CDMA 1X modem (off) and returns to step 501 to continuously wait. Check whether the handover condition is satisfied. In addition, if the CDMA 1X modem handles outgoing / incoming calls before processing Idle State Indication, the CDMA 1X modem is deactivated (off) and the WCDMA modem is given priority. Check whether it satisfies.

Upon receiving the wait state indication signal, the WCDMA modem transmits a terminal mode change request signal to the control unit (step 513). The controller converts the mode of the mobile terminal from WCDMA to CDMA 1X mode by deactivating the WCDMA modem according to the terminal mode change request signal, and transmits the result to the terminal mode change response signal to the WCDMA modem (step 515). ).

6 is a diagram illustrating parameters in an SIB 3 message according to an embodiment of the present invention.

Referring to FIG. 6, the SIB 3 message of the 3GPP standard is a message that the mobile terminal receives from the WCDMA system in a standby state, and includes cell selection and re-selection information. The SIB 3 message includes several parameters, and the RAT List 601, the RAT identifier 603, the S _{search, RAT} 605, the S _{HCS, RAT} 607, and the S _limit for the standby handover according to the present invention. _{, searchRAT} 609 is used. At this time, the RAT identifier 603 is set to cdma2000, and maxOtherRAT of the RAT List 601 is set to 3 to secure an area of a parameter to be transmitted from the network. maxOtherRAT can be extended as needed due to future improvements to the standby handover algorithm. A value with a RAT List (601) of 1 is used to set a back off time parameter for handover from a CDMA 1X standby state to a WCDMA standby state. The RAT List (601) has a value of 2 and 3 The value is used to transmit a threshold and time-to-trigger condition by RSCP, Ec / Io, respectively, to the terminal. In this case, the S _{HCS, RAT} 607 value represents a threshold condition, and the S _{limit, searchRAT} 609 value represents a time-to-trigger condition. On the other hand, the contents of the RAT List = 3 containing the contents of the Ec / Io is preferably transmitted to the mobile terminal only in the WCDMA border cell, from which the mobile terminal can distinguish the WCDMA border cell.

FIG. 7 is a diagram for describing parameter values indicating a standby handover condition to which RSCP is applied according to an embodiment of the present invention.

Referring to FIG. 7, a mobile terminal receives a setting value of an information element transmitted from a network and applies the value without modification to the corresponding application. If the RAT List value is set to 2, the mobile station applies Received Signal Code Power (RSCP) in performing the standby handover. S _{HCS, RAT} represents TH_on_idle_RSCP, which is a threshold value for activating the CDMA 1X modem. When S _{HCS, RAT} is set to -105, the mobile terminal applies this value to TH_on_idle_RSCP as it is. S _{limit, searchRAT} indicates _{T_on_idle_RSCP,} a time-to-trigger value for activating the CDMA 1X modem. When S _{limit, searchRAT} is set to 5, the mobile terminal applies this value to T_on_idle_RSCP as it is.

In the above example where H_on_idle_RSCP has a value of -105 and T_on_idle_RSCP has a value of 5, the mobile terminal determines that the handover condition is satisfied when the RSCP value of the WCDMA system is less than -105 and lasts 5 seconds or longer. Handover to the synchronous system.

FIG. 8 is a diagram for describing parameter values representing a standby handover condition to which Ec / Io is applied according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the mobile terminal receives a setting value of an information element transmitted from a network and applies the value without modification to the corresponding application. If the RAT List value is set to 3, the mobile terminal applies Ec / Io in performing the standby handover. As such, the RAT List = 3 is transmitted from the WCDMA border cell to the mobile terminal, and the mobile terminal will apply the Ec / Io condition when performing the standby handover in the WCDMA border cell.

S _{HCS, RAT} indicates TH_on_idle_SNR, the threshold for activating the CDMA 1X modem. When S _{HCS, RAT} is set to -10, the mobile terminal applies this value to TH_on_idle_SNR. S _{limit, searchRAT} indicates _{T_on_idle_SNR,} a time-to-trigger value for activating the CDMA 1X modem. When S _{limit, searchRAT} is set to 5, the mobile terminal applies this value to T_on_idle_RSCP as it is.

In the above example where H_on_idle_SNR has a value of -10 and T_on_idle_SNR has a value of 5, the mobile terminal determines that the handover condition is satisfied when the Ec / Io value of the WCDMA system signal is less than -10 and lasts more than 5 seconds. To perform a handover to CDMA 1X (synchronous system).

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

According to the present invention, by providing a method and apparatus for performing standby handover from a WCDMA system to a synchronous system, the user of the WCDMA system can be facilitated.

According to the present invention, an optimal standby handover may be performed by adjusting parameters in an SIB 3 message received in a standby state and an internal timer of the mobile terminal.                     

According to the present invention, changes to existing mobile terminals and systems can be minimized, and standby handover can be performed without a separate network construction such as a beacon.

Claims (14)

1. A method for performing a standby handover from the WCDMA system to the synchronous system in a mobile terminal comprising a WCDMA modem and a synchronous modem, the WCDMA system being coupled to a WCDMA system and a synchronous system. Receiving a standby handover condition from the WCDMA system in a WCDMA mode; Determining whether the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Activating the synchronous modem when the determination result satisfies a standby handover condition; Receiving a pilot signal and a synchronization signal from the synchronous system using the synchronous modem to enter a standby state; And Turning off the WCDMA modem to switch from WCDMA mode to synchronous mode And a standby handover from a WCDMA system to a synchronous system. The method of claim 1, The synchronous modem is a CDMA 1X modem And a standby handover from a WCDMA system to a synchronous system. The method of claim 1, The standby handover condition is received through an SIB 3 message in an idle state And a standby handover from a WCDMA system to a synchronous system. delete The method of claim 1, The Ec / Io is applied in a border cell And a standby handover from a WCDMA system to a synchronous system. The method of claim 3, When RSCP is applied, the handover condition is satisfied when RSCP of the WCDMA system lasts more than TH_on_idle_RSCP or more than T_on_idle_RSCP. And a standby handover from a WCDMA system to a synchronous system. The method of claim 3, When Ec / Io is applied, the handover condition is satisfied when Ec / Io of the WCDMA system persists below TH_on_idle_SNR or more than T_on_idle_SNR. And a standby handover from a WCDMA system to a synchronous system. The method of claim 6, The TH_on_idle_RSCP and T_on_idle_RSCP are the values set in the S _{HCS, RAT} , S _{limit, and SearchRAT} parameters in the SIB 3 message, respectively. And a standby handover from a WCDMA system to a synchronous system. The method of claim 7, wherein The TH_on_idle_SNR and T_on_idle_SNR are values set in the S _{HCS, RAT} , S _{limit, and SearchRAT} parameters in the SIB 3 message, respectively. And a standby handover from a WCDMA system to a synchronous system. A method for performing a standby handover from the WCDMA system to the synchronous system in a WCDMA modem included in a mobile terminal coupled with a WCDMA system and a synchronous system, the method comprising: Receiving a standby handover condition from the WCDMA system; Determining whether the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Transmitting a synchronous modem activation request signal to a control unit included in the mobile terminal when the determination result is satisfied, wherein the control unit corresponds to the synchronous modem activation request signal and includes the synchronous modem included in the mobile terminal; Activate the signal, and the synchronous modem receives a pilot signal and a synchronous signal from the synchronous system and enters a standby state; Receiving a first standby state indication signal from the controller, wherein the first standby state indication signal corresponds to a second standby state indication signal received by the controller from the synchronous modem in response to entering the standby state; ; And Transmitting a terminal mode change request signal to the controller; Including but not limited to: The control unit turns off the WCDMA modem to change the state of the mobile terminal from WCDMA mode to synchronous mode And a standby handover from a WCDMA system to a synchronous system. A method for performing a standby handover from the WCDMA system to the synchronous system in a synchronous modem included in a mobile terminal coupled with a WCDMA system and a synchronous system, the method comprising: Receiving a first synchronous modem activation request signal from a control unit included in the mobile terminal, wherein the first synchronous modem activation request signal is a WCDMA modem included in the mobile terminal receiving a standby handover condition from the WCDMA system; And corresponding to the second synchronous modem activation request signal transmitted to the control unit when the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition. To; Activating by the first synchronous modem activation request signal; Receiving a pilot signal and a synchronization signal from the synchronous system and entering a standby state; And Transmitting a first standby state indication signal to the controller when entering a standby state Including but not limited to: The control unit transmits a second standby state indication signal to the WCDMA modem in response to the first standby state indication signal, receives a terminal mode change request signal from the WCDMA modem, and then turns off the WCDMA modem. Changing the state of the mobile terminal from WCDMA mode to synchronous mode And a standby handover from a WCDMA system to a synchronous system. A mobile terminal comprising a WCDMA modem and a synchronous modem, the standby terminal having a standby handover from the WCDMA system to the synchronous system in combination with a WCDMA system and a synchronous system, Means for receiving a standby handover condition from the WCDMA system in a WCDMA mode; Means for determining whether a signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Means for activating the synchronous modem when the determination result satisfies a standby handover condition; Means for receiving a pilot signal and a synchronous signal from the synchronous system using the synchronous modem to enter a standby state; And Means for turning off the WCDMA modem to switch from WCDMA mode to synchronous mode Mobile terminal comprising a. A WCDMA modem included in a mobile terminal combined with a WCDMA system and a synchronous system for performing a standby handover from the WCDMA system to the synchronous system, Means for receiving a standby handover condition from the WCDMA system; Means for determining whether a signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition; Means for transmitting a synchronous modem activation request signal to a controller included in the mobile terminal when the determination result is satisfied, wherein the controller is a synchronous modem included in the mobile terminal in response to the synchronous modem activation request signal. Activate the signal, and the synchronous modem receives a pilot signal and a synchronous signal from the synchronous system and enters a standby state; Means for receiving a first standby state indication signal from the control unit, wherein the first standby state indication signal corresponds to a second standby state indication signal received by the control unit from the synchronous modem in response to entering the standby state; ; And Means for transmitting a terminal mode change request signal to the controller Including, The control unit turns off the WCDMA modem to change the state of the mobile terminal from WCDMA mode to synchronous mode WCDMA modem characterized in that. A synchronous modem included in a mobile terminal combined with a WCDMA system and a synchronous system to perform a standby handover from the WCDMA system to the synchronous system, Means for receiving a first synchronous modem activation request signal from a control unit included in the mobile terminal, wherein the first synchronous modem activation request signal is a WCDMA modem included in the mobile terminal receiving a standby handover condition from the WCDMA system; And corresponding to the second synchronous modem activation request signal transmitted to the control unit when the signal strength of at least one of a received signal code power (RSCP) and an Ec / Io signal transmitted from the WCDMA system satisfies the standby handover condition. To; Means for activating by the first synchronous modem activation request signal; Means for receiving a pilot signal and a synchronization signal from the synchronous system and entering a standby state; And Means for transmitting a first standby state indication signal to the controller when entering a standby state Including, The control unit transmits a second standby state indication signal to the WCDMA modem in response to the first standby state indication signal, receives a terminal mode change request signal from the WCDMA modem, and then turns off the WCDMA modem. Changing the state of the mobile terminal from WCDMA mode to synchronous mode A synchronous modem, characterized in that.

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