KR100486545B1 - Hand-off method for dual band dual mode terminal - Google Patents

Abstract

The present invention relates to a handoff method of a dual-band dual board terminal. In the related art, in order to reduce power consumption in a third generation service area, the present invention leaves the third generation service area and moves to the second generation service area while the code division multiple access block is turned off. When entering, there is a problem that the time required to switch to the second generation system by turning on the code division multiple access block. In view of the above problems, the present invention provides a method of determining whether a call drop has occurred previously by referring to call drop information of a current cell stored in a database when a user terminal camps on a service cell; Initiating a code division multiple access block power on / off control task when determining that the call drop was present; In the current cell, it is determined whether a call drop occurs, and if so, the call drop information is stored in the database, and power is supplied to a code division multiple access block to convert to a code division multiple access communication service. By supporting the code division multiple access call service by recognizing the movement from the area to the shadow area in advance, the service switching time is faster and the power consumption is reduced to increase the battery life.

Description

HAND-OFF METHOD FOR DUAL BAND DUAL MODE TERMINAL

The present invention relates to a method for supporting handoff decision for mobility support in a dual band dual mode terminal. In particular, the present invention relates to a code division multiple access call service by recognizing a shift from a wideband code division multiple access call area to a shadow area in advance. The present invention relates to a handoff method of a dual band dual mode terminal which can be directly supported.

Due to the development of mobile communication technology and the evolution of communication networks, various types of mobile communication systems are being developed and standardized. However, due to the interests of each country, it is impossible to establish a uniform standard and system. It is divided into W-CDMA system led by US and IS-2000 system led by US, and is proceeding standardization and development of IMT-2000.

In Korea, the existing 2nd generation mobile phone system adopts the synchronous method to provide services, and commercialization of the CDMA 2000 system, which is the initial IMT-2000 system, is being promoted.

However, in the future, 3G systems are likely to adopt asynchronous W-CDMA systems, and service providers' efforts to adopt the W-CDMA systems are continuing. Synchronous system and asynchronous system will coexist.

A handoff method of a conventional dual band dual mode terminal for providing mobility service between a synchronous system and an asynchronous system will now be described with reference to the accompanying drawings.

1 is a network construction diagram for explaining a handoff method of a conventional dual-band dual-mode terminal, the mobile terminal 10, 12 may be a dual-band dual-mode terminal capable of supporting both a synchronous system and an asynchronous system. For example, the terminal may be a terminal dedicated to the third generation asynchronous system or a terminal dedicated to the second generation synchronous system.

If the mobile terminal 10, 12 is a terminal capable of supporting both a synchronous system and an asynchronous system, each of the synchronous system and the asynchronous system independently has a protocol stack for each of the terminals, and supports one air interface at a time. It becomes a dual band dual mode terminal. That is, an asynchronous service is provided in the service area of the asynchronous system (third generation mobile communication system), and a synchronous service is provided in the service area of the synchronous system (second generation mobile communication system).

As shown in FIG. 1, an asynchronous system will be constructed in stages to form a service area, and the service area in the existing synchronous mobile communication system will be included.

In the network type as described above, the mobile terminal 10 is currently located in the cell B of the third generation system, and selects an asynchronous IMT-2000 system in the system selection process, and drives a protocol corresponding thereto. In the case of the mobile terminal 12, it is currently located in the cell E of the second generation system, and the second generation synchronous system is selected in the system selection process, and the corresponding protocol is driven.

When the mobile terminal 10 moves in the direction of the arrow, since the service area is changed from the 3rd generation asynchronous IMT-2000 system to the synchronous system, an intersystem handoff occurs from the asynchronous system to the synchronous system. Done.

For handoff, neighboring cell information on a neighboring second generation system must be informed to the mobile terminal from the third generation control station. Currently, the asynchronous system defines this in a system information message. Similarly, in the case of the mobile terminal 12, the second generation control station receives the information on the neighbor cell in the third generation system.

The handoff between systems performs power measurement based on the information on these neighboring cells, thereby performing the handoff after determining the handoff cell. However, in such a system environment, there may be various types of mobile terminals, and accordingly, it is determined whether handoff is possible. That is, when the mobile terminal 12 is a dedicated terminal capable of supporting only a second generation synchronous system, the second generation control station may not inter-system handoff but only inter-cell handoff for cell F of the second generation synchronous system. Perform. In addition, when the mobile terminal 10 is a dedicated terminal for the third generation asynchronous IMT-2000 system, the inter-system handoff to the cell A of the second generation synchronous system does not need to be performed. To support this, the network must know the service capability information of the mobile terminal before the handoff. When the network knows the service capability information of the mobile terminal, neighboring cell information can be selectively transmitted to reduce the signal load on the system and prevent unnecessary handoff attempts.

The method of transmitting service capability information of a mobile terminal to a network is different from a synchronous 2nd generation system and an asynchronous 3rd generation system. That is, in the synchronous 2nd generation system, the protocol revision number is included in the outgoing message and transmitted to notify the network of the overall support capability of the mobile terminal, and the provided service is adjusted through the service option negotiation procedure.

In contrast, in the third generation asynchronous IMT-2000 system, the mobile terminal notifies the network of the range of services it can provide through a service capability message. Therefore, for smooth handoff, the mobile terminal should be able to simultaneously transmit these two pieces of information. To this end, when the dual mode terminal operates in the synchronous second generation system area, the service capability information of the terminal for operating in the third generation asynchronous system for a message including information related to the service capability of the terminal together with an outgoing message Contains a field. Similarly, even when the dual band dual mode terminal operates in the service area of the asynchronous system, the service capability message of the terminal includes protocol revision number information necessary when operating in the synchronous system.

However, in the prior art as described above, the dual band dual mode terminal always maintains the code division multiple access block and the wideband code division multiple access block in an operational state for smooth handoff in the second generation or third generation service area. There is a problem that the battery life is reduced due to the increased power consumption.

In addition, when the code division multiple access block is turned off to enter the second generation service area while the code division multiple access block is turned off to reduce power consumption in the third generation service area, the code division multiple access block is turned on to switch to the second generation system. There is a problem that the time required is increased.

Accordingly, the present invention has been made in view of the above-mentioned problems. The present invention provides a database of whether to camp on when moving from a current serving cell to an adjacent cell, and controls on / off a code division multiple access block with reference to a database when entering the same cell next time. An object of the present invention is to provide a handoff method of a dual band dual mode terminal.

The present invention for achieving the above object comprises the steps of determining whether a call drop has occurred previously with reference to the call drop information for the current cell stored in the database when camping on the service cell in the user terminal; Initiating a code division multiple access block power on / off control task when determining that the call drop was present; If it is determined that the call drop occurs in the current cell, the call drop information is stored in the database, and the power is supplied to the code division multiple access block.

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

FIG. 2 is a diagram illustrating a configuration of a wideband code division multiple access network to which the present invention is applied. As shown in FIG. 2, the dual band dual mode terminal 20 instructs a cell reselection from a searcher of a physical layer. When receiving, the base station controller 40 requests a system information block (SIB) for all neighboring cells and receives it through a broadcast control channel (BCCH). At this time, the optimum cell is found and camped on.

When the call drop occurs before the cell reselection, the dual band dual mode terminal 20 converts the drop information of the current serving cell into a database in the terminal and refers to the database 24 when camping on the current serving cell later. In order to prepare for the call drop and to camp on the code division multiple access service area in advance, power is applied to the code division multiple access block to make it operational.

FIG. 3 is a block diagram showing the configuration of a main part of a dual band dual mode terminal, and as shown therein, a code division multiple access block 22 connected to a code division multiple access system, which is a second generation mobile communication system; A wideband code division multiple access block (23) connected to a wideband code division multiple access system which is a third generation mobile communication system; The main control unit 21 controls the operations of the two blocks 22 and 23.

The dual band dual mode terminal includes a code division multiple access block 22 and a wideband code division multiple access block 23 for communication with second and third generation mobile communication systems. Control the operation of the two blocks to keep the call available at all times.

Here, the operation state of the code division multiple access block when the dual band dual mode terminal moves from the service area controlled by the 3rd generation mobile communication system to the service area controlled by the second generation mobile communication system will be described with reference to the accompanying drawings. .

4 is a diagram illustrating a configuration of a serving cell and an adjacent cell according to a moving direction of the user terminal. As shown in FIG. 4, when the user terminal camps on the serving cell 62, a call drop for the current cell 62 is shown. The database storing the information is searched to see if there was a call drop before moving to the adjacent cell 61.

For example, if the user terminal 63 moves in the direction B, the call drop does not occur, but if the user terminal 63 moves in the direction A, the call drop occurs and the call drop information is stored in the database. Therefore, since there is a risk of a call drop when the user terminal enters a service cell, a power on / off control task is activated for a code division multiple access block to prepare for a quick switch to a code division multiple access service area when a call drop occurs.

FIG. 5 is a flowchart illustrating a handoff method of a dual band dual mode terminal according to the present invention. As shown in FIG. 5, when a user terminal is camped on a serving cell, a call drop information of a current cell stored in a database is previously described. Determining whether a call drop has occurred (S11, S12); Starting a code division multiple access block power on / off control task when it is determined that the call drop exists (S20); In operation S13 to S15, the call drop information is stored in the database, and if the call drop is generated in the current cell, the call drop information is stored in the database and the power is supplied to the code division multiple access block.

When the user terminal camps on the service cell, it is determined whether a call drop has occurred previously by referring to the call drop information of the current cell stored in the database (S11 and S12).

If it is determined that there is a call drop, the user terminal starts a code division multiple access block power on / off control task (S20).

The code division multiple access block power on / off control task turns on the power to the code division multiple access block and makes it operable and maintains this state for a predetermined time (S21 and S22).

When the predetermined time elapses, the control task switches the code division multiple access block to a deep sleep state and maintains this state for a predetermined time (S23 and S24). Thereafter, when a predetermined time elapses, the operation is stopped by turning off the power supplied to the code division multiple access block (S25).

When the operation of the control task is summed up, the mobile station waits for movement to the code division multiple access service area for a predetermined time, and deep sleeps the code division multiple access block when the call drop does not occur in the broadband code division multiple access service area for a predetermined time. If it is in the state and is still in a broadband code division multiple access service area for some time and no call drop occurs, then power is turned off for the code division multiple access block.

After the control task is activated, the user terminal determines whether a call drop occurs, and if so, stores the call drop information of the current service cell in a database and supplies power to a code division multiple access block to switch to a code division multiple access communication service. (S13-S15).

If a call drop does not occur, the user terminal continuously refers to the call drop information of the current cell in the database, and if there is a call drop, starts the code division multiple access block on / off control task and repeats the operation of checking the presence of the call drop. .

As described in detail above, the present invention recognizes the shift from the wideband code division multiple access call area to the shadow area of the service in advance, thereby directly supporting the code division multiple access call service, thereby speeding up the service switching time and power consumption. It has the effect of increasing the battery life by reducing.

1 is a network diagram for explaining a handoff method of a conventional dual-band dual-mode terminal.

2 is a diagram illustrating a configuration of a wideband code division multiple access network to which the present invention is applied.

Figure 3 is a block diagram showing the configuration of the main part of the dual-band dual-mode terminal for explaining the operation of FIG.

4 is a diagram illustrating a configuration of a service cell and an adjacent cell according to a moving direction of a user terminal.

5 is an operation flowchart of a handoff method of a dual band dual mode terminal according to the present invention;

Claims (2)

Determining whether a call drop has occurred previously by referring to call drop information of a current cell stored in a database when the user terminal camps on a service cell; Initiating a code division multiple access block power on / off control task when determining that the call drop was present; Judging whether or not a call drop occurs in the current cell, if the call drop information is stored in the database, and supplying power to a code division multiple access block to convert to a code division multiple access communication service. Handoff method of dual mode terminal. The method according to claim 1, wherein the code division multiple access block power on / off control task comprises the steps of: powering on a code division multiple access block to make it operable and maintaining the state for a predetermined time; Transitioning the code division multiple access block to a deep sleep state after the predetermined time has elapsed and maintaining the state for a predetermined time; When the predetermined time elapses, turning off the power supplied to the code division multiple access block and stopping the operation.