KR20060116454A - Handover method for dual band/dual mode mobile communication terminal - Google Patents

Abstract

A handover method in a dual band/dual mode mobile communication terminal is provided to perform the handover to an asynchronous network if received power from the asynchronous network is bigger than the first designated threshold value, perform the handover to a synchronous network if the received power from the asynchronous network is lower than the second threshold value, and differentially set the first and second threshold values, thereby inhibiting frequent ping-pong phenomena. A handover method in a dual band/dual mode mobile communication terminal comprises the following steps of: enabling a mobile communication terminal, which is being connected with a synchronous mobile communication network through a synchronous wireless device, to convert an asynchronous wireless device from a low power mode into an idle state and search a pilot signal from an asynchronous mobile communication network(S101); confirming whether asynchronous pilot signal strength is bigger than the first threshold value(S103); if not so, returning to the first step, and if so, acquiring system information of an asynchronous mobile communication system(S107); performing location registration to the asynchronous mobile communication system(S109); and converting the synchronous wireless device into the low power mode and then performing the handover to the asynchronous mobile communication network by an asynchronous modem(S111).

Description

Handover Method for Dual Band / Dual Mode Mobile Communication Terminal

1 is a block diagram illustrating a connection relationship between a mobile communication terminal and a mobile communication network according to the present invention;

2 is a block diagram for explaining the configuration of a mobile communication terminal applied to the present invention;

3 is a block diagram illustrating a configuration of a common module of FIG. 2;

4 is a conceptual diagram illustrating a handover of a mobile communication terminal in a mixed region of an asynchronous mobile communication network and a synchronous mobile communication network according to the present invention;

5 is a flowchart illustrating a handover process of a mobile communication terminal according to an embodiment of the present invention;

6 is a view for explaining a handover process of a mobile communication terminal according to another embodiment of the present invention.

<Brief description of the main parts of the drawing>

100: asynchronous mobile communication network 200: synchronous mobile communication network

400: mobile communication terminal 410: antenna

420: asynchronous radio 430: synchronous radio

440: common module 443: main processor

The present invention relates to a handover method of a dual band / dual mode mobile communication terminal, and more particularly, to a dual band / dual mode mobile communication terminal in a region where a synchronous mobile communication network (CDMA) and an asynchronous mobile communication network (WCDMA) overlap. The present invention relates to a handover method of a dual band / dual mode mobile terminal for minimizing frequent ping-pong phenomenon caused by frequent location registration between asynchronous and synchronous when in a WCDMA shadow area.

Currently, mobile communication service technology can be broadly classified into an asynchronous service environment centered on Europe and a synchronous service centered on North America. In addition, the IMT-2000 service is evolving around North America and Europe as a new mobile communication technology standard for delivering packets at high speed.

Synchronous IMT-2000 service (synchronous mobile communication network) is developed as CDMA2000 1x, CDMA2000 1x EV-DO, and asynchronous IMT-2000 service (asynchronous mobile communication network) is developed as WCDMA UMTS service. Doing. In such an environment, the problem of roaming between synchronous and asynchronous is the biggest problem. Accordingly, a terminal supporting dual band / dual mode has been developed to smoothly roam a synchronous mobile network and an asynchronous mobile communication network.

On the other hand, the asynchronous mobile communication network is built around the area with high service demands. Accordingly, in the synchronous mobile communication network, the service area includes the service area of the asynchronous system. In this process, the user synchronizes with the asynchronous mobile communication system. In the case of mutual movement between mobile communication systems, handover between systems is required for continuous service provision. Accordingly, various handover schemes have been proposed.

However, the asynchronous-synchronous handover scheme considered up to now mainly targets handover in the boundary area of the asynchronous mobile communication network, and an unexpected problem may occur in the shaded area in the asynchronous mobile communication network area. Is a ping-pong phenomenon between asynchronous and synchronous networks in a building.

Ping-Pong is a phenomenon that can occur when you try to use the asynchronous and synchronous handover function in a building or other WCDMA shadow area. When the terminal is idle in the WCDMA shadow area, neighboring asynchronous mobile network forces are asynchronous. In this case, if the specific trigger condition that needs to be handed over synchronously is satisfied, the UE proceeds from asynchronous to synchronous handover, and if it is determined that it is overlapped with the asynchronous mobile communication network, the handover is performed asynchronously again. .

That is, in the 32-bit Base ID, which is a system parameter value of the synchronous mobile communication network mixed with the asynchronous mobile communication network, the value of the field indicating whether the mobile terminal is mixed with the asynchronous mobile communication network is set to "1". After handover to the mobile communication network, the terminal performs handover to the asynchronous mobile communication network again based on the parameter value in order to use the asynchronous service to the maximum, thereby repeating the ping-pong phenomenon.

Currently, in order to prevent such frequent ping-pong phenomenon, the mobile communication terminal of the synchronous mode switches a modem after a specified time (for example, AT ⁿ ) and attempts to register a location with an asynchronous network. Switch to increase the latency (for example, n = n + 1), then switch the modem to attempt location registration to the asynchronous network. Here, A is a parameter for the asynchronous signal search interval, T is a basic interval for asynchronous signal search, n is a value between 0≤n≤Nmax, Nmax represents the maximum number of asynchronous signal search. In this case, modem switching is performed at a specified time period, and asynchronous signal search is repeated according to the modem switching, so that a period during which an asynchronous signal is searched frequently occurs. In addition, when the asynchronous wireless environment is temporarily improved, the handover to the asynchronous mode and the handover to the synchronous mode are performed again. At this time, the waiting time for searching for the asynchronous signal is reset. There is a disadvantage.

In addition, a paging signal cannot be transmitted to the mobile communication terminal during the asynchronous signal search period, which causes a problem in that the quality of service is degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above disadvantages and problems, wherein the reception power from the asynchronous network is greater than the first threshold value in the shaded area of the asynchronous service among the mixed areas of the asynchronous mobile communication network area and the synchronous mobile communication network area. After the handover to the asynchronous network and after the handover to the asynchronous network, if the received power from the asynchronous network is less than or equal to the second threshold, the handover to the synchronous network is performed. However, the first and second thresholds are set differently, so that the frequent The technical problem is to make it possible to suppress the ping-pong phenomenon.

Another technical problem of the present invention is to register a location in an asynchronous network when the pilot signal strength from the asynchronous network is larger than the first threshold value in the shadow area of the asynchronous service among the mixed areas of the asynchronous mobile communication network area and the synchronous mobile communication network area. The technical challenge is to enable asynchronous network search without affecting the synchronous network service by performing and switching modems.

According to an aspect of the present invention, an asynchronous wireless device for performing asynchronous communication with the asynchronous mobile communication network and a synchronous communication with the synchronous mobile communication network are provided in a mobile communication network in which an asynchronous mobile communication network and a synchronous mobile communication network are mixed. A handover method of a dual band dual mode mobile communication terminal, comprising: a synchronous radio device and a common module for performing control during radio communication with the synchronous / asynchronous mobile communication network through the synchronous and asynchronous radio devices. A first step of the mobile communication terminal connecting to the synchronous mobile communication network through the wireless device to switch the asynchronous wireless device from the low power mode to the idle state to retrieve a pilot signal from the asynchronous mobile communication network; A second step of checking whether the asynchronous pilot signal strength is greater than a first threshold; A third step of returning to the first step if the asynchronous pilot signal strength is less than or equal to a first threshold, and acquiring system information of the asynchronous mobile communication system if the asynchronous pilot signal strength is greater than a first threshold; A fourth step of performing location registration with the asynchronous mobile communication system; And a fifth step of switching the synchronous radio to a low power mode and handing over to the asynchronous mobile communication network by the asynchronous modem unit.

The present invention also provides an asynchronous wireless device for performing asynchronous communication with the asynchronous mobile communication network, a synchronous wireless device for performing synchronous communication with the asynchronous mobile communication network in a mobile communication network in which an asynchronous mobile communication network and a synchronous mobile communication network are mixed. And a handover method of a dual band dual mode mobile communication terminal having a common module for performing control in wireless communication with the synchronous / asynchronous mobile communication network through the synchronous and asynchronous wireless devices. A first step of the mobile communication terminal switching to an asynchronous mode; A second step of measuring, by the mobile communication terminal, the power of a signal received from an asynchronous mobile communication network to determine whether the magnitude of the asynchronous signal reception power is greater than a first threshold; A third step of switching to a synchronous mode when the magnitude of the asynchronous signal reception power is equal to or less than a first threshold value, and performing a handover to the asynchronous mobile communication network when the magnitude of the asynchronous signal reception power is greater than the first threshold value; A fourth step of determining, by the mobile communication terminal handing over to the asynchronous mobile communication network, the power of the signal received from the asynchronous mobile communication network to determine whether the amount of the asynchronous signal reception power is greater than a second threshold; And a fifth step of returning to the fourth step when the magnitude of the asynchronous signal reception power is greater than a second threshold value, and switching to a synchronous mode and performing a handover when the size of the asynchronous signal reception power is less than the second threshold value.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Minimize service discovery periods and avoid paging loss.

In addition, by applying different handover reference values to the asynchronous network and the synchronous network, the ping pong phenomenon can be minimized.

1 is a block diagram illustrating the configuration of a synchronous and asynchronous mobile communication network according to the present invention.

As shown in FIG. 1, an asynchronous mobile communication network (WCDMA network) 100 is a wireless station controller (hereinafter referred to as' RNC) that controls a wireless station 101 and a wireless station 101 that perform wireless communication with the mobile communication terminal 400. 102 and a Serving GPRS Service Node (SGSN) 103 connected to the RNC 102 to manage mobility of the mobile communication terminal 400; And an asynchronous communication network data service gateway node (hereinafter referred to as 'GGSN') 106 which is a relay that performs packet service control and packet data delivery through the GPRS network 105.

In addition, an RNC 102 is connected to an exchange 104 which performs call exchange (hereinafter referred to as 'MSC') 104, and the MSC 104 is a number seven signal network (No. 7 signal network) 107 for signal exchange. Connected with. The number seven signal network 107 includes a short message service center (hereinafter referred to as 'SMSC') 108, an intelligent network controller (hereinafter referred to as 'SCP') 109, which serves a short message, and subscriber's location information. A home location register (hereinafter referred to as 'HLR') 110 for management is connected.

On the other hand, the synchronous mobile communication network (CDMA2000 network) 200, the base station (hereinafter referred to as 'BTS') that performs radio communication with the mobile communication terminal 400 and the base station controller (controlling the BTS 201) 202), a Packet Data Service Node (hereinafter referred to as "PDSN") 204 connected to the BSC 202 and serving packet data, and a PDSN 204. A Data Core Network (hereinafter referred to as "DCN") 209 that is connected and performs an Internet access service, and an Exchanger (hereinafter referred to as "MSC") that is connected to the BSC 202 to perform an exchange (203) It is configured to include).

The MSC 203 is connected with a number seven signal network (No. 7 signal network) 205 for signal exchange. The number seven signal network 205 includes a short message service center (hereinafter referred to as 'SMSC') 206, an intelligent network controller (hereinafter referred to as 'SCP') 207, and a subscriber's location information for serving a short message. A home location register (hereinafter referred to as 'HLR') 208 for management is connected.

The MSCs 104 and 203 of the asynchronous mobile communication network 100 and the synchronous mobile communication network 200 are connected to each other, and the number seven signal networks 107 and 205 are also connected to each other, such as handover of the mobile communication terminal 400 and the like. Send and receive the necessary information.

In addition, in this embodiment, the synchronous mobile communication network 200 and the asynchronous mobile communication network 100 have HLRs 110 and 208 for managing subscriber information and location information, respectively, but one HLR (dual stack home location register). By using the synchronous mobile communication network 200 and the asynchronous mobile communication network 100 may share the subscriber information and location information.

2 is a block diagram illustrating a configuration of a dual band mobile communication terminal applied to the present invention.

As shown, the dual-band mobile communication terminal 400 is to support both synchronous and asynchronous mobile communication has a stack of each protocol.

The mobile communication terminal 400 applied to the present invention is broadly divided into an antenna 410 for transmitting and receiving radio waves with the synchronous mobile communication network 200 and the asynchronous mobile communication network 100, and the synchronous radio apparatus 430 for synchronous communication. And, asynchronous radio 420 for asynchronous communication, and a common module 440 for providing common resources in synchronous and asynchronous communication.

The synchronous radio apparatus 430 includes a synchronous radio transmitter 432 for radio transmission, a synchronous radio receiver 433 for radio reception, and a synchronous modem unit 434. The synchronous radio transmitter 432 and synchronous radio One side of the receiver 433 is connected to the antenna 410 through the duplexer 431, and the other side thereof is connected to the synchronous modem unit 434.

The asynchronous radio apparatus 420 also includes an asynchronous radio transmitter 422 for radio transmission, an asynchronous radio receiver 423 for radio reception, and an asynchronous modem unit 424, and includes an asynchronous radio transmitter 422 and an asynchronous radio. One side of the receiver 423 is connected to the antenna 410 through the duplexer 421 and the other side is connected to the asynchronous modem unit 424.

Meanwhile, the common module 440 includes an application processor, a memory, an input / output unit, other application processing units, etc. that operate as a central processing unit for controlling the synchronous modem unit 434 and the asynchronous modem unit 424 and perform multimedia functions. Detailed configuration is as follows.

3 is a block diagram illustrating a configuration of a common module of FIG. 2.

As illustrated, the common module 440 of the mobile communication terminal according to the present invention includes a plurality of dual port RAMs connected to the modem units 424 and 434 of the synchronous radio 430 and the asynchronous radio 420. (Dual Port RAM, hereinafter referred to as 'DPRAM') 441 and 442, the main processor is connected to the DPRAM (441 and 442) and performs the overall control of the synchronous and asynchronous communication of the mobile communication terminal 400 and the application execution 444. The main processor 443 is connected to a memory 444 for storing data, an I / O device 445 for connecting a peripheral device, and a power control module (hereinafter referred to as 'PWM') 446 for power control. do.

The common module 440 having such a configuration is equipped with software for a user interface, additional service, mobility management, access / session control, resource control, and protocol processing, so that a user can use various application services and handover. Performs protocol conversion according to the mobile communication system.

4 is a conceptual diagram of handover in a mobile communication network in which an asynchronous network and a synchronous network are mixed according to an embodiment of the present invention.

As shown, the handover in the present invention is performed in the mobile communication terminal 400 in the region where the asynchronous mobile communication network 100 and the synchronous mobile communication network 200 are mixed, in particular, the asynchronous mobile communication network 100 Even when the mobile communication terminal 400 is in an environment in which the radio wave environment is poor, such as in a building, the mobile communication terminal 400 in an idle state (IDLE) is asynchronous mobile communication network 100 and synchronous mobile communication network 200. Handover the liver.

In one embodiment of the present invention, the synchronous modem portion of the mobile communication terminal 400 is in an on state and the asynchronous modem portion operates in a low power mode. In this state, the asynchronous modem unit searches for the asynchronous pilot signal, and receives the system information from the asynchronous network and executes the location registration when the asynchronous pilot signal strength is greater than the specified first threshold value THw. Switch to use asynchronous network service. After modem switching, the synchronous modem unit makes the transition to the low power mode.

In addition, after handing over to the asynchronous network, it is confirmed whether the pilot signal strength from the asynchronous network is larger than the designated second threshold value THc, and if the asynchronous pilot signal strength is less than or equal to the second threshold value THc, the hand is returned to the synchronous network again. Over.

The mobile communication terminal indicates whether the synchronous mobile communication network 200 is mixed with the asynchronous mobile communication network 100 among base IDs, which are system parameters of the synchronous mobile communication network 200, after handover to the synchronous network. When it is determined that the parameter value (0 or 1) of the field is a value (= 1) indicating that the mixed area of the synchronous mobile communication network 200 and the asynchronous mobile communication network 100 is 1, handover to the asynchronous mobile communication network 100 again.

As described above, even when the handover between the asynchronous network and the synchronous network is repeatedly performed, in the present invention, since the asynchronous modem unit determines the handover by measuring the asynchronous pilot signal strength in the low power mode, the service from the synchronous mobile communication system is affected. The handover can be performed without giving a notice. In addition, the ping-pong phenomenon can be minimized by differently setting the threshold condition THw for handover to the asynchronous network and the threshold condition THc for handover to the synchronous network.

In another embodiment of the present invention, the mobile communication terminal 400 has a synchronous modem portion in the on (on) state and the asynchronous modem portion in the off (off) state, by switching from the synchronous mode to the asynchronous mode, the asynchronous mobile communication network 100 If the received power is greater than the first threshold value THw, handover to the asynchronous mobile communication network 100 is performed. When the handover is successful, the mobile communication terminal 400 periodically checks the received power from the asynchronous and synchronous mobile communication networks 100 and 200, so that the received power from the asynchronous mobile communication network 100 is the second threshold value THc. ) Or less, and performs handover to the synchronous mobile communication network 200 again.

That is, rather than performing a handover between the asynchronous and synchronous mobile communication networks 100 and 200 based on one reference value, the handover is performed based on a threshold value differently set according to the characteristics of each of the asynchronous and synchronous mobile communication networks 100 and 200. To do. In this case, after the handover to the asynchronous mobile communication network 100, the state connected to the asynchronous mobile communication network 100 until the received power from the asynchronous mobile communication network 200 becomes less than the specified value (second threshold value) Because of this, the ping pong phenomenon can be prevented from occurring frequently.

5 is a flowchart illustrating a handover process of a mobile communication terminal according to an embodiment of the present invention.

The mobile communication terminal is in an idle state connected to the synchronous network, and the asynchronous modem unit operates in a low power mode. Further, if it is determined that the parameter value (0 or 1) of the field indicating whether the synchronous mobile communication network is mixed with the asynchronous mobile communication network is a value (= 1) indicating that it is a mixed area of the synchronous mobile communication network and the asynchronous mobile communication network, In order to handover to the mobile communication network, the asynchronous modem unit in a low power state is switched to an idle state and searches for an asynchronous pilot signal (S101). In this case, the asynchronous modem unit is to wait for a predetermined time according to the specified timer value to switch to the idle state. In addition, the asynchronous modem unit in the idle state checks whether the asynchronous pilot signal strength is greater than the first threshold value THw (S103), and performs a handover to the asynchronous network when the first threshold value THw is greater than the first threshold value THw. In this case, it is also possible to perform a handover by checking whether the asynchronous pilot signal strength is maintained for a predetermined time Hd (w) in a state larger than the first threshold value THw (S105). Handover may be made.

In order to perform a handover to the asynchronous network, the system information from the asynchronous network is acquired (S107), and after performing location registration (S109), the synchronous modem unit and the asynchronous modem unit are switched to use the services of the asynchronous network and synchronized. The modem unit is switched to the low power mode (S111).

Herein, the mobile communication terminal searches for pilot signals from neighboring nodes B according to a channel numbering scheme (UARFCN) used for radio channel identification in an asynchronous mobile communication system, and if the pilot signals are not found, for the remaining B bands. Search for a pilot signal.

After performing the handover as described above, if the mobile communication terminal is still located in an area where asynchronous service is poor, such as in a building, the mobile communication terminal must perform handover to the synchronous network again.

To this end, the asynchronous modem unit of the mobile communication terminal periodically searches for an asynchronous pilot signal (S113) and checks whether it is larger than the second threshold value THc (S115). As a result of the check, when the asynchronous pilot signal strength is larger than the second threshold value THc, the handover is not performed to the synchronous network and the asynchronous mode is continuously maintained. In this way, the ping-pong phenomenon can be prevented from occurring frequently by varying the handover condition to the asynchronous network and the handover condition to the synchronous network (THw> THc).

On the other hand, when the asynchronous pilot signal strength is less than or equal to the second threshold value THc, handover is performed to the synchronous network. For handover to the synchronous network, first, the synchronous modem unit in the low power state switches to the idle state, acquires system information from the base station of the synchronous mobile communication system (S117), and performs location registration (S119). Switch to use the service of the synchronization network (S121).

6 is a view for explaining a handover process of a mobile communication terminal according to another embodiment of the present invention.

In this embodiment, the mobile communication terminal is in an idle state in connection with a synchronous network, and the asynchronous modem unit is in an off state. Further, if it is determined that the parameter value (0 or 1) of the field indicating whether the synchronous mobile communication network is mixed with the asynchronous mobile communication network is a value (= 1) indicating that it is a mixed area of the synchronous mobile communication network and the asynchronous mobile communication network, In order to handover to the mobile communication network, the modem is switched and is in an idle state (S201). In this case, the asynchronous modem unit is to wait for a predetermined time according to the specified timer value to switch to the idle state.

The mobile communication terminal which has switched to the asynchronous mode measures the power of the signal received from the asynchronous mobile communication network and checks whether the received power is greater than the first threshold value THw (S203). As a result of the check, when the size of the asynchronous reception power is larger than the first threshold value THw, the asynchronous modem unit performs location registration with the asynchronous mobile communication network and performs handover (S205). On the other hand, when the magnitude of the asynchronous signal reception power is less than or equal to the first threshold value THw, the mobile communication terminal switches back to the synchronous mode (S207).

The mobile communication terminal handing over to the asynchronous mobile communication network in step S205 measures the received power of the signal received from the neighboring base station at a specified period, and checks whether the received power of the asynchronous signal is greater than the second threshold value THc (S209). ). If the reception power of the asynchronous signal is greater than the second threshold value THc as a result of the confirmation of step S209, the process proceeds to step S209 of checking the reception power of the asynchronous signal, and if it is less than or equal to the second threshold value THc, the synchronous mode. In step S211, handover is performed (S213).

On the other hand, after step S207 it is preferable that the mobile communication terminal to maintain the synchronous mode for a predetermined time before switching to the asynchronous mode.

In the present embodiment, the asynchronous priority mode mobile communication terminal connected to the synchronous network in the asynchronous service shadow area of the mixed asynchronous network and the synchronous network is handed over to the asynchronous network because the strength of the asynchronous pilot signal is larger than the specified threshold THw. After that, handover to the synchronous network is performed only when the received power from the asynchronous mobile communication network is equal to or less than the specified threshold value THc. In this way, the ping-pong phenomenon between the asynchronous network and the synchronous network can be minimized. In addition, the first and second thresholds are preferably set (THw> THc) such that the first threshold has a larger value than the second threshold in consideration of characteristics of the mobile communication network.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

According to the present invention described above, in the mixed region of the asynchronous mobile communication network and the synchronous mobile communication network, any modem unit of the dual band / dual mode mobile communication terminal switches from the low power state to the idle state to search for a pilot signal of the handover target system. For example, if the pilot signal strength is greater than the specified value, paging loss can be prevented by connecting a modem when registration is completed after registration is performed.

In addition, by applying different handover reference values to the asynchronous network and the synchronous network, the ping pong phenomenon can be minimized.

Claims (7)

In a mobile communication network in which an asynchronous mobile communication network and a synchronous mobile communication network are mixed, an asynchronous wireless device for performing asynchronous communication with the asynchronous mobile communication network, a synchronous wireless device for performing synchronous communication with the synchronous mobile communication network, and the synchronous and asynchronous communication. A handover method of a dual band dual mode mobile communication terminal having a common module for performing control during wireless communication with the synchronous / asynchronous mobile communication network through a wireless device, A first step of retrieving a pilot signal from an asynchronous mobile communication network by the mobile communication terminal connected to the synchronous mobile communication network through the synchronous wireless device, switching the asynchronous wireless device from a low power mode to an idle state; A second step of checking whether the asynchronous pilot signal strength is greater than a first threshold; A third step of returning to the first step if the asynchronous pilot signal strength is less than or equal to a first threshold, and acquiring system information of the asynchronous mobile communication system if the asynchronous pilot signal strength is greater than a first threshold; A fourth step of performing location registration with the asynchronous mobile communication system; And A fifth step of switching the synchronous radio to a low power mode and handing over to the asynchronous mobile communication network by the asynchronous modem unit; Handover method of a dual band / dual mode mobile communication terminal comprising a. The method of claim 1, The third step further includes checking whether the asynchronous pilot signal strength is maintained for a predetermined time greater than the first threshold value before acquiring system information when the asynchronous pilot signal strength is greater than the first threshold. Handover method of a dual-band / dual mode mobile communication terminal, characterized in that. The method of claim 1, A sixth step after the fifth step, the asynchronous radio device searching for the asynchronous pilot signal; A seventh step of checking whether the asynchronous pilot signal strength is greater than a second threshold; When the asynchronous pilot signal strength is greater than the second threshold, the method returns to the sixth step. When the asynchronous pilot signal strength is less than or equal to the second threshold value, the synchronous wireless device in a low power mode switches to an idle state to perform the synchronous mobile communication. An eighth step of obtaining system information from the system; A ninth step of performing location registration with the synchronous mobile communication system; And A tenth step of switching the asynchronous radio to a low power mode and handing over to the synchronous mobile communication network by the synchronous radio; A handover method of a dual band / dual mode mobile communication terminal further comprising. The method of claim 3, wherein The second threshold value is set smaller than the first threshold value, the handover method of a dual-band / dual mode mobile communication terminal. In a mobile communication network in which an asynchronous mobile communication network and a synchronous mobile communication network are mixed, an asynchronous wireless device for performing asynchronous communication with the asynchronous mobile communication network, a synchronous wireless device for performing synchronous communication with the synchronous mobile communication network, and the synchronous and asynchronous communication. A handover method of a dual band dual mode mobile communication terminal having a common module for performing control during wireless communication with the synchronous / asynchronous mobile communication network through a wireless device, A first step of switching to an asynchronous mode from a mobile communication terminal in an idle state connected to the synchronous network; A second step of measuring, by the mobile communication terminal, the power of a signal received from an asynchronous mobile communication network to determine whether the magnitude of the asynchronous signal reception power is greater than a first threshold; A third step of switching to a synchronous mode when the magnitude of the asynchronous signal reception power is equal to or less than a first threshold value, and performing a handover to the asynchronous mobile communication network when the magnitude of the asynchronous signal reception power is greater than the first threshold value; A fourth step of determining, by the mobile communication terminal handing over to the asynchronous mobile communication network, the power of the signal received from the asynchronous mobile communication network to determine whether the amount of the asynchronous signal reception power is greater than a second threshold; And A fifth step of returning to the fourth step if the magnitude of the asynchronous signal reception power is greater than a second threshold value, and switching to a synchronous mode and performing a handover if the asynchronous signal reception power is less than the second threshold value; Handover method of a dual band / dual mode mobile communication terminal comprising a. The method of claim 5, In the third step, after the switching to the synchronous mode when the magnitude of the asynchronous signal reception power is less than or equal to the first threshold value, the mobile communication terminal waits for a specified time and then returns to the first step. A handover method of a band / dual mode mobile communication terminal. The method of claim 5, The second threshold value is set smaller than the first threshold value, the handover method of a dual-band / dual mode mobile communication terminal.

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