KR20050077196A - System for hand-over between asynchronous communication network and synchronous communication network and hand-over method thereof - Google Patents

Abstract

The present invention provides a mobile communication system and a handover method for improving the success rate of handover from an asynchronous network to a synchronous network in a mobile communication system in which an asynchronous network overlaps a synchronous network.

The mobile communication system of the present invention includes a handover cell of a size specified at the boundary between the asynchronous mobile communication system and the synchronous mobile communication system. The handover method is a mobile communication terminal that acquires system information from the handover cell region. Driving the modem unit and requesting handover to the asynchronous mobile communication system, driving the synchronous modem unit and transitioning to the idle state, and receiving the handover command from the asynchronous mobile communication system to the synchronous modem unit. Transmitting a channel assignment message; turning off the asynchronous modem unit by the mobile communication terminal and switching the vocoder; and obtaining the synchronization with the synchronous mobile communication system.

According to the present invention, it is possible to sufficiently secure the synchronous modem driving time, thereby preventing a call disconnection and unnecessary power consumption.

Description

System for Hand-over Between Asynchronous Communication Network and Synchronous Communication Network and Hand-over Method Thereof}

The present invention relates to a handover method in a mobile communication network, and more particularly, in a mobile communication system in which an asynchronous network is superimposed on a synchronous network, a mobile communication system for improving handover success rate from an asynchronous network to a synchronous network. And a handover method.

With the development of mobile communication technology and the evolution of communication networks, various types of mobile communication systems are being developed. Accordingly, the IMT-2000 system has been developed to solve the global roaming problem between mobile communication systems. IMT-2000 system is divided into CDMA2000 based synchronous system and WCDMA based asynchronous system.

In addition, in order to support global roaming between mobile communication systems, a mobile communication terminal (Multi Mode Multi Band Mobile Communication Terminal) capable of being used in both a synchronous system and an asynchronous system has been developed. This allows different types of services to be used in each of the asynchronous system domain and the synchronous system domain.

Currently, asynchronous mobile communication systems are being built around regions with high service demands, and accordingly, synchronous mobile communication systems have evolved to include service areas of asynchronous system. When a user moves between an asynchronous mobile communication system and a synchronous mobile communication system, handover between systems is required for continuous service provision.

However, since asynchronous mobile communication systems and synchronous mobile communication systems have different communication methods, it is very difficult to implement handover between systems, and the proposed handover scheme has a limitation in increasing the handover success rate. In addition, since the multi-mode multi-band mobile communication terminal also has two modems, it is very important to determine when to run and turn off the two modems.

More specifically, the multimode multiband mobile communication terminal requires a handover during the use of the asynchronous mobile communication system service, so that it takes about 10 seconds to drive the synchronous modem for communicating with the synchronous mobile communication system. The synchronous modem unit must be driven before the call with the mobile communication system is disconnected. If the synchronous modem unit is not driven until it is completely out of the asynchronous mobile communication system area, the handover is not made and the call is disconnected. If the synchronous modem unit is driven earlier than necessary, the two modems are simultaneously on. Since the power consumption is disadvantageous. As such, since the timing of driving the synchronous modem unit is not known accurately, problems such as disconnection and power consumption occur during handover.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and provides an area of sufficient time to perform a handover in the boundary area between the asynchronous area and the synchronous area for handover from the asynchronous mobile communication system to the synchronous mobile communication system. With a handover cell having a handover cell, the mobile communication terminal moving from the asynchronous area to the synchronization area drives the synchronous modem according to the system information received from the handover cell and requests to perform handover, thereby allowing sufficient margin for driving the synchronous modem. There is a technical problem to provide a mobile communication system and a handover method that can improve the handover success rate as the handover is performed with.

In the present invention for achieving the above technical problem is a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system is mixed, and a handover cell of a predetermined size exists between the asynchronous mobile communication system and the synchronous mobile communication system, A method for controlling a mobile communication terminal for handover of a multimode multiband mobile communication terminal having an asynchronous modem unit and a synchronous modem unit, wherein a mobile communication terminal using a service of the asynchronous mobile communication system passes through the handover cell region. As the mobile station moves to the synchronous area, the asynchronous modem unit of the mobile communication terminal acquires system information transmitted by the handover base station of the handover cell area, and the synchronous modem unit of the mobile communication terminal is driven to the asynchronous mobile communication system. A first step of requesting handover; A second step of the mobile communication terminal driving the synchronous modem unit and transitioning to an idle state; A third step of transmitting a channel assignment message to the synchronous modem unit when the asynchronous modem unit of the mobile communication terminal receives a handover command from the asynchronous mobile communication system; A fourth step of the mobile communication terminal turning off the asynchronous modem unit and switching a vocoder; And a fifth step of acquiring synchronization with the synchronous mobile communication system by the synchronous modem unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a mobile communication terminal refers to a multimode multiband mobile communication terminal that can be used in both an asynchronous mobile communication system and a synchronous mobile communication system. The mobile communication terminal can receive a synchronous mobile communication system signal using a synchronous modem unit while using a service of an asynchronous mobile communication system, and a signal and a synchronous mobile communication system using a synchronous modem unit while using a service of an asynchronous mobile communication system. It can be divided into a form that can transmit and receive, a detailed description will be described later.

1 is a block diagram of a mobile communication network to which the present invention is applied.

The multi-mode multiband mobile communication terminal 10 may use a voice and data service by wirelessly connecting the asynchronous mobile communication system 20 and the synchronous mobile communication system 30, respectively.

The asynchronous mobile communication system 20 is a wireless network controller (Node B / RNC, 210) for controlling Node B and Node B as a base station for wireless section communication with the mobile communication terminal 10, wireless network controller 210 Short service center connected with the asynchronous exchange (MSC, 220), the asynchronous exchange 220 and the No.7 common signal network 230 to perform a call exchange for providing a service to the mobile communication terminal (10) (SMSC, 240), the intelligent network controller (SCP, 250) and home location register (HLR, 260), the wireless network controller 210 and the GPRS (General Packet Radio Service) network 280 is connected to the mobile communication terminal (10) Is connected via a Serving GPRS Support Node (SGSN) 270, a SGSN 270, and a General Packet Radio Service (GPRS) network 280, which maintains a location track of the < RTI ID = 0.0 > And a Gateway GPRS Support Node (GGSN) 290 connected to and supporting interworking with external packets.

In addition, the synchronous mobile communication system 30 is connected to the mobile communication terminal 10 and the base station controller (BTS / BSC, 310) for controlling the base station and the base station for supporting the wireless section communication, and connected to one or more base station controller to perform a call exchange Short-term service center (SMSC, 340), intelligent network controller (SCP, 350) and home location register (HLR) connected through an exchange (MSC) 320, an exchange 320, and a No. 7 common signaling network 330 to perform 360, a data core network for supporting a connection between a packet data service node (PDSN, 370) and a packet data service node 370 and the Internet 40 to be connected to a base station controller to provide a packet data service to a subscriber ( DCN, 380 is configured.

The switches 220 and 320 of the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 are interconnected by the No. 7 common signal networks 230 and 330, and the handover of the mobile communication terminal 10 is performed. Send and receive the necessary information. In addition, the home location registers 260 and 360 may be implemented as a dual stack home location register. The home location registers 260 and 360 may store and manage subscriber information, additional service usage status, and provide subscriber information according to a request of the exchange 220 or 320. .

2 is a structural diagram of a mobile communication terminal applied to the present invention.

As shown, the multi-mode multi-band mobile communication terminal 10 applied to the present invention includes an antenna 110, a module 120 for asynchronous mobile communication service, a module 130 for synchronous mobile communication service and a common module. And 140.

The antenna 110 may simultaneously process a frequency band for a synchronous mobile communication service and a frequency band for an asynchronous mobile communication service.

The asynchronous module 120 includes a duplexer 121 that operates as a band pass filter for separating and processing respective frequencies, an asynchronous wireless transceiver 122 for separating transmission and reception radio waves into a predetermined frequency band, and a wireless section with an asynchronous mobile communication system. A synchronous modem 130 for processing protocols and a vocoder 124 for performing encryption and decryption of voice signals, and the synchronization module 130 operates as a duplexer that operates as a band pass filter for classifying and processing respective frequencies. 131, a synchronous wireless transceiver 132 for separating transmission and reception radio waves into a predetermined frequency band, a synchronous modem unit 133 for processing a wireless section protocol with a synchronous mobile communication system, and for encrypting and decrypting a voice signal Vocoder 134.

The common module 140 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 asynchronous modem unit 123 and the synchronous modem unit 133 and perform multimedia functions.

In addition, the multi-mode multi-band mobile communication terminal 10 is equipped with software for the user interface, additional services, mobility management, connection / session control, resource control, protocol processing, so that the user can use a variety of application services, Handover is performed and protocol conversion is performed according to the mobile communication system.

The mobile communication terminal described above is a terminal capable of receiving a signal of a synchronous mobile communication system while using a service of an asynchronous mobile communication system, and a terminal capable of transmitting and receiving a signal with a synchronous mobile communication system while using a service of an asynchronous mobile communication system. Can be distinguished. In the case of a mobile communication terminal capable of transmitting and receiving signals to and from a synchronous mobile communication system while using a service of an asynchronous mobile communication system, a device configuration such as duplexers 121 and 131 becomes somewhat more complicated than a mobile communication terminal capable of only receiving signals, Designed to take into account impacts.

Referring back to FIG. 1, FIG. 1 shows a system configuration diagram of the asynchronous mobile communication system 20 and the synchronous mobile communication system 30. The present invention provides the asynchronous mobile communication system 20 with the synchronous mobile communication system 30. In the actual construction so as to overlap each other, an additional handover cell region is constructed at the boundary region of the asynchronous region and the synchronous region. The handover cell includes a handover base station and transmits a signal including system information indicating that the mobile communication terminal is located in the handover cell to a mobile communication terminal belonging to the handover cell area. Here, the signal including the system information uses the same frequency as the frequency used in the asynchronous mobile communication system.

The system information transmission signal includes a specific scramble code to distinguish it from other cells (asynchronous cell, sync cell), and it is preferable to use 512 scramble codes. In addition, the boundary distance between the handover cell region, that is, the asynchronous region and the synchronous region, may be calculated and constructed as shown in [Equation 1] in consideration of the moving speed of the mobile communication terminal.

[Equation 1]

S _HOCELL = V _MS * T _HO

Here, S _HOCELL is the size of the handover cell, that is, the distance between the asynchronous area and the synchronization area, V _MS means the moving speed of the mobile communication terminal, T _HO means the time required for handover. For example, it can be set to 10 to 20 seconds.

In such a system environment, as the mobile communication terminal 10 existing in the asynchronous mobile communication system region moves to the synchronous mobile communication system region, the mobile communication terminal 10 transmits a signal transmitted from the handover base station in the handover cell region. By receiving the signal, the signal is driven by the asynchronous mobile communication system to drive the synchronous modem unit and perform a handover, thereby establishing a connection with the synchronous mobile communication system.

In addition, the handover cell accepts a call only for a mobile communication terminal performing a handover from an asynchronous network to a synchronous network, restricts generation of outgoing and incoming calls to the asynchronous mobile communication system in the handover cell, and synchronizes the synchronous mobile communication system. By accepting outgoing and incoming call origination, the call quality is not reduced.

3 is a conceptual diagram of a handover using a handover cell in a mobile communication network in which an asynchronous network and a synchronous network are mixed.

As the mobile communication terminal 10 using the service in the asynchronous area A moves to the synchronization area B, the mobile communication terminal 10 receives a signal transmitted from the handover cell area C. . The signal transmitted from the base station (BTS _HO , 410) of the handover cell area (C) includes system information indicating that the current position of the mobile communication terminal 10 is the handover cell area (C). The mobile communication terminal 10 receiving the request requests a handover to the asynchronous mobile communication system 20 while driving the synchronous modem unit, and the asynchronous mobile communication system 20 receiving the handover request must perform a handover unconditionally. do.

As described above, the asynchronous mobile communication system 20 commands the handover unconditionally at the request of the mobile communication terminal 10 to suppress the ping-pong phenomenon occurring at the boundary area between the asynchronous network and the synchronous network. . The ping pong phenomenon refers to a phenomenon in which handover is repeatedly performed as power intensity changes frequently in an intercell boundary region.

According to the handover command of the asynchronous mobile communication system 20, the mobile communication terminal 10 switches the modem and the vocoder and performs handover with the synchronous mobile communication system 30. The modem and vocoder switching process may be performed by handover with the synchronous mobile communication system 30 according to the type of the mobile communication terminal 10 (when the mobile communication terminal is capable of both transmitting and receiving signals with the synchronous mobile communication system among asynchronous mobile communication services). It is also possible to carry out afterwards.

4 is a flowchart illustrating a handover method according to an embodiment of the present invention, a method for handover when the mobile communication terminal can only receive the synchronous mobile communication system signal while using the service of the asynchronous mobile communication system. Indicates.

As the mobile communication terminal using the service of the asynchronous mobile communication system gradually moves from the asynchronous area through the handover cell area to the synchronous area, the asynchronous modem part of the mobile communication terminal is present from the base station in the handover cell area. In operation S101, a message including system information indicating that the location is a handover cell area is received. Here, the signal including the system information uses the same frequency as the frequency used in the asynchronous mobile communication system.

The asynchronous modem unit of the mobile communication terminal receiving the system information from the base station in the handover cell area transmits a message requesting to drive the synchronous modem to the synchronous modem unit (S102), and a message requesting handover to the asynchronous mobile communication system. It is transmitted (S103). After performing the initialization procedure of the modem and preparing to search the pilot channel of the synchronous mobile communication system (S104), the synchronous modem unit of the mobile communication terminal searches for the pilot channel and the synchronization channel of the synchronous mobile communication system (S105, S106). ), And transition to the idle state (S107).

Thereafter, the asynchronous modem unit receives a handover command from the asynchronous mobile communication system (S108), and transmits a channel assignment message to the synchronous modem unit (S109). Here, the channel assignment message includes the parameters necessary for the synchronous modem to transition from the idle state to the traffic state.

After the synchronous modem unit receives the channel assignment message, the asynchronous modem unit is turned off (OFF), the asynchronous vocoder 124 is turned off, and the synchronous vocoder 134 is driven to switch the vocoder (S110). Transition (S111). Next, in order to synchronize with the synchronous mobile communication system, the reverse traffic is transmitted (S112), and the handover is reported to the base station of the synchronous mobile communication system (S113).

Since the mobile communication terminal applied to the present embodiment is a terminal capable of only receiving a signal from the synchronous mobile communication system during service use of the asynchronous mobile communication system, the synchronous modem unit should transmit reverse traffic after the asynchronous modem unit is turned off.

FIG. 5 is a flowchart illustrating a handover method according to another embodiment of the present invention, in which a mobile communication terminal is capable of transmitting and receiving a signal with a synchronous mobile communication system while using a service of an asynchronous mobile communication system. The method is shown.

In this embodiment, the asynchronous modem unit acquires system information from the base station in the handover cell area, transmits a synchronous modem unit driving command, transmits a handover command to the asynchronous mobile communication system, and then, when the synchronous modem unit is driven, asynchronous mobile communication. The process of receiving a handover command from the system and transmitting a channel assignment message to the synchronous modem by the asynchronous modem is the same as the handover method described with reference to FIG. 4.

That is, as the mobile communication terminal using the service of the asynchronous mobile communication system moves to the synchronous area through the handover cell area, the asynchronous modem unit of the mobile communication terminal acquires system information from the base station of the synchronous handover cell area ( In step S201, the asynchronous modem unit requests the synchronous modem to be driven by the synchronous modem unit (S202), and requests a handover to the asynchronous mobile communication system (S203). Here, the signal including the system information uses the same frequency as the frequency used in the asynchronous mobile communication system.

Accordingly, the synchronous modem unit prepares for initializing the modem and searching for a pilot channel of the synchronous mobile communication system (S204), and after searching for a pilot channel and a synchronous channel of the synchronous mobile communication system (S205 and S206), the idle state. Transition to (Idle State) (S207). Thereafter, if the asynchronous mobile communication system instructs to perform the handover (S208), the asynchronous modem unit transmits a channel assignment message to the synchronous modem unit (S209).

Next, the synchronous modem unit transitions to the traffic state (S210), and transmits reverse traffic to synchronize with the synchronous mobile communication system (S211). Subsequently, the synchronous modem unit reports to the base station of the synchronous mobile communication system that the handover is completed (S212), and then switches off the vocoder by turning off the asynchronous modem, turning off the asynchronous vocoder, and driving the synchronous vocoder (S213).

Since the mobile communication terminal applied to the present embodiment has a function of transmitting a signal to the synchronous mobile communication system while using the asynchronous mobile communication system service, the mobile communication terminal transmits backward traffic to the synchronous mobile communication system before turning off the asynchronous modem unit to move synchronously. Synchronize with the communication system. The present embodiment can provide a more improved service compared to a mobile communication terminal capable of receiving a signal of a synchronous mobile communication system while the mobile communication terminal is using an asynchronous mobile communication service. That is, in the case of a mobile communication terminal capable of receiving a signal of a synchronous mobile communication system while using an asynchronous mobile communication service, the synchronization is synchronized with the synchronous mobile communication system after turning off the asynchronous modem unit. Will be. However, the mobile communication terminal capable of transmitting and receiving signals with the synchronous mobile communication system during the use of the asynchronous mobile communication service is almost silent because the asynchronous modem is turned off after synchronizing with the synchronous mobile communication system.

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. 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 a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed, a handover cell area having a size specified in a boundary area between an asynchronous area and a synchronization area for handover of a multimode multiband mobile communication terminal. When the mobile communication terminal enters the handover cell region, handover is performed by the system information message received from the base station in the handover cell region, thereby allowing the mobile terminal to move from the asynchronous region to the synchronization region. Allow yourself time to spare.

As described above, as the mobile communication terminal moves from the asynchronous region to the synchronous region and performs a handover with sufficient time margin, the asynchronous modem is turned off before the synchronous modem is driven, or the synchronous modem and the asynchronous modem are simultaneously driven and the battery It can prevent the phenomenon that is consumed more than necessary.

1 is a configuration diagram of a mobile communication network to which the present invention is applied;

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

3 is a conceptual diagram of handover in a mobile communication network in which an asynchronous network and a synchronous network are mixed;

4 is a flowchart illustrating a handover method according to an embodiment of the present invention;

5 is a flowchart illustrating a handover method according to another embodiment of the present invention.

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

10: multi-mode multi-band mobile communication terminal 20: asynchronous mobile communication system

30: synchronous mobile communication system 40: Internet

110: antenna 120: asynchronous module

121, 131: duplexer 122: asynchronous wireless transceiver

123: asynchronous modem unit 124, 134: vocoder

130: synchronization module 132: synchronous wireless transceiver

133: synchronous modem unit 140: common module

210: Node B / wireless network controller 220: asynchronous switch

230, 330: No.7 common signal network 240, 340: Short service center

250, 350: intelligent network controller 260, 360: home location register

270: SGSN 280: GPRS network

290: GGSN 310: base station / base station controller

320: switch 370: packet data service node

380 data core network

Claims (10)

In a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed and a handover cell having a specified size exists between the asynchronous mobile communication system and the synchronous mobile communication system, a multimode including an asynchronous modem unit and a synchronous modem unit. A mobile communication terminal control method for handover of a multi-band mobile communication terminal, As the mobile communication terminal using the service of the asynchronous mobile communication system moves to the synchronous area through the handover cell area, the asynchronous modem unit of the mobile communication terminal is transmitted by the handover base station of the handover cell area Acquiring information, causing the synchronous modem unit of the mobile communication terminal to be driven, and requesting a handover to the asynchronous mobile communication system; A second step of the mobile communication terminal driving the synchronous modem unit and transitioning to an idle state; A third step of transmitting a channel assignment message to the synchronous modem unit when the asynchronous modem unit of the mobile communication terminal receives a handover command from the asynchronous mobile communication system; A fourth step of the mobile communication terminal turning off the asynchronous modem unit and switching a vocoder; And A fifth step of acquiring synchronization with the synchronous mobile communication system by the synchronous modem; Handover method comprising a. In a mobile communication network in which an asynchronous mobile communication system and a synchronous mobile communication system are mixed and a handover cell having a specified size exists between the asynchronous mobile communication system and the synchronous mobile communication system, a multimode including an asynchronous modem unit and a synchronous modem unit. A mobile communication terminal control method for handover of a multi-band mobile communication terminal, The multi-mode multi-band mobile communication terminal is a mobile communication terminal capable of transmitting and receiving signals with the synchronous mobile communication system while using the service of the asynchronous mobile communication system, As the mobile communication terminal using the service of the asynchronous mobile communication system moves to the synchronous area through the handover cell area, the asynchronous modem unit of the mobile communication terminal is transmitted by the handover base station of the handover cell area Acquiring information, causing the synchronous modem unit of the mobile communication terminal to be driven, and requesting a handover to the asynchronous mobile communication system; A second step of the mobile communication terminal driving the synchronous modem unit and transitioning to an idle state; A third step of transmitting a channel assignment message to the synchronous modem unit when the asynchronous modem unit of the mobile communication terminal receives a handover command from the asynchronous mobile communication system; A fourth step of acquiring synchronization with the synchronous mobile communication system by the synchronous modem; And A fifth step of the mobile communication terminal turning off the asynchronous modem unit and switching a vocoder; And Handover method comprising a. The method according to claim 1 or 2, And the system information obtained by the mobile communication terminal from the handover base station has the same frequency as that used in the asynchronous mobile communication system. The method of claim 3, wherein And a signal including system information transmitted by the handover base station includes a scramble code indicating cell information in which the mobile communication terminal is located. The method according to claim 1 or 2, The second process may include: performing, by the synchronous modem, an initialization procedure of the synchronous modem and preparing a pilot channel search of the synchronous mobile communication system; Searching, by the synchronous modem unit, a pilot channel and a synchronous channel of the synchronous mobile communication system; And Transitioning to the idle state by the synchronous modem unit; Handover method comprising a. The method according to claim 1 or 2, The process of acquiring synchronization with the synchronous mobile communication system by the synchronous modem may include transitioning to the traffic state by the synchronous modem; Transmitting, by the synchronous modem unit, reverse traffic to a base station of the synchronous mobile communication system; And Reporting, by the synchronous modem unit, that handover is completed to the synchronous mobile communication system; Handover method comprising a. The method according to claim 1 or 2, The size of the handover cell is S _HOCELL = V _MS * T _HO , S _HOCELL is the size of the handover cell, V _MS is the moving speed of the mobile communication terminal, T _HO is characterized in that the time required for handover Handover method. Synchronous mobile communication network; An asynchronous mobile communication network overlapping the synchronous mobile communication system; And A handover cell positioned at a boundary between the synchronous mobile communication system and the asynchronous mobile communication system and including a handover base station configured to transmit a signal having a frequency equal to a frequency used in the asynchronous mobile communication system; A signal transmitted by the handover base station as the multimode multiband mobile communication terminal having an asynchronous modem unit and a synchronous modem unit moves through the handover cell area to the synchronous mobile communication network area through the asynchronous mobile communication network area. The mobile communication system characterized in that for receiving the mobile communication terminal to perform a handover. The method of claim 8, And the signal transmitted by the handover base station includes a scramble code indicating cell information in which the mobile communication terminal is located. The method of claim 8, The size of the handover cell is S _HOCELL = V _MS * T _HO , S _HOCELL is the size of the handover cell, V _MS is the moving speed of the mobile communication terminal, T _HO is characterized in that the time required for handover Mobile communication system.