Mobile communication system and method for implementing handoff

• US 20030104815A1
• Filed: 10/28/2002
• Published: 06/05/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sung-Won
• Granted Patent: US 7,389,110 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node

Abstract

A handoff implementing method in a mobile communication system having a planar structure, in which at least two BSCs are connected to at least two BTSs through a RAN. An MT transmits a first Handoff Request message containing its information and information about its anchor BSC to a target BTS when it moves to a handoff zone. Upon receipt of the first Handoff Request message, the target BTS transmits a second Handoff Request message containing the MT information and its information to the anchor BSC. Upon receipt of the second Handoff Request message, the anchor BSC transmits a traffic signal directed to the MT to the target BTS.

Claims

1. A method for implementing a handoff for an MT (Mobile Terminal) in a mobile communication system in which at least two BSCs (Base Station Controllers) are connected to at least two BTSs (Base Transceiver Systems) through a RAN (Radio Access Network), each of the BSCs controls at least one BTS, and each of the BTSs as a source BTS provides information about an anchor BSC that is serving a call to an MT at a call setup, comprising the steps of:

storing anchor BSC information received from a source BTS at a call setup;

transmitting to a target BTS a first Handoff Request message containing the anchor BSC information when a handoff is requested; and

processing a call through the target BTS upon receipt from the target BTS of a response signal.

2. A method for implementing a handoff for a target BTS (Base Transceiver System) in a mobile communication system in which at least two BSCs (Base Station Controllers) are connected to at least two BTSs through a RAN (Radio Access Network), each of the BSCs controls at least one BTS, and each of the BTSs as a source BTS provides information about an anchor BSC that is serving a call to an MT (Mobile Terminal) at a call setup, comprising the steps of:

transmitting to the anchor BSC of an MT a second Handoff Request message containing information about an MT and information about the target BTS upon receipt from the MT, of a first Handoff Request message containing information about the anchor BSC; and

forwarding traffic data to the MT upon receipt of the traffic data directed to the MT from the anchor BSC.

3. A method for implementing a handoff for an anchor BSC that is serving a call to an MT (Mobile Terminal) in a mobile communication system in which at least two BSCs (Base Station Controllers) are connected to at least two BTSs (Base Transceiver Systems) through a RAN (Radio Access Network), each of the BSCs controls at least one BTS, and each of the BTSs as a source BTS provides information about the anchor BSC of an MT at a call setup, comprising the step of:

releasing a channel connected to a source BTS and establishing the channel to a target BTS for an MT to which the anchor BSC is serving a call upon receipt of a second Handoff Request message containing information about the target BTS and information about the MT.

4. A handoff method among a source BTS (Base Transceiver System), a target BTS, and an anchor BSC (Base Station Controller) for transmitting a traffic signal to the source BTS in a mobile communication system in which at least two BSCs are connected to at least two BTSs through a RAN (Radio Access Network), comprising the steps of:

transmitting a first Handoff Request message containing information about an MT (Mobile Terminal) and information about the anchor BSC from the MT to the target BTS when the MT moves to a handoff zone;

transmitting a second Handoff Request message containing the MT information and information about the target BTS from the target BTS to the anchor BSC upon receipt of the first Handoff Request message; and

transmitting a traffic signal directed to the MT from the anchor BSC to the target BTS upon receipt of the second Handoff Request message.

5. A handoff method among a source BTS (Base Transceiver System), a target BTS, and an anchor BSC (Base Station Controller) for transmitting a traffic signal to the source BTS in a mobile communication system in which at least two BSCs are connected to at least two BTSs through a RAN (Radio Access Network) having a database of information about anchor BSCs for MTs (Mobile Terminals) communicating with BTSs, comprising the steps of:

transmitting from the MT to the target BTS a first Handoff Request message containing information about an MT when the MT moves to a handoff zone;

detecting by the target BTS the anchor BSC of the MT from the database upon receipt of the first Handoff Request message;

transmitting to the anchor BSC a second Handoff Request message containing information about the target BTS and the MT information from the target BTS; and

transmitting a traffic signal directed to the MT from the anchor BSC to the target BTS upon receipt of the second Handoff Request message.

6. A handoff method among a source BTS (Base Transceiver System), a target BTS, and an anchor BSC (Base Station Controller) for transmitting a traffic signal to the source BTS in a mobile communication system in which at least two BSCs are connected to at least two BTSs through a RAN (Radio Access Network), comprising the steps of:

transmitting from the MT to the target BTS a first Handoff Request message containing information about an MT when the MT moves to a handoff zone;

broadcasting a Search Request message for searching by the target BTS for the anchor BSC of the MT over the RAN upon receipt of the first Handoff Request message;

transmitting from the target BTS to the anchor BSC a second Handoff Request message containing information about the target BTS and the MT information upon receipt of a Search Response message indicating the anchor BSC over the RAN; and

transmitting a traffic signal directed to the MT from the anchor BSC to the target BTS upon receipt of the second Handoff Request message.

7. A system for implementing a handoff in a mobile communication system in which at least two BSC (Base Station Controllers) are connected to at least two BTSs (Base Transceiver Systems) through a RAN (Radio Access Network), comprising:

an MT (Mobile Terminal) for transmitting to a target BTS a first Handoff Request message containing information about the MT and information about an anchor BSC of the MT when the MT moves to a handoff zone;

the target BTS for transmitting to the anchor BSC a second Handoff Request message containing the MT information and information about the target BTS upon receipt of the first Handoff Request message, and providing a traffic service to the MT when a handoff is completed; and

the anchor BSC for transmitting a traffic signal directed to the MT to the target BTS over the RAN upon receipt of the second Handoff Request message.

8. A system for implementing a handoff in a mobile communication system in which at least two BSC (Base Station Controllers) are connected to at least two BTSs (Base Transceiver Systems) through a RAN (Radio Access Network), comprising:

an MT (Mobile Terminal) for transmitting to a target BTS a first Handoff Request message containing information about the MT when the MT moves to a handoff zone;

a database connected to the RAN, for storing information about an anchor BSC that serves the MT and providing the anchor BSC information upon request;

the target BTS for requesting the database to search for the anchor BSC of the MT using the MT information upon receipt of the first Handoff Request message, transmitting to the anchor BSC a second Handoff Request message containing information about the target BTS and the MT information when the target BTS obtains the anchor BSC information from the database, and providing a traffic service to the MT when a handoff is completed; and

the anchor BSC for transmitting a traffic signal directed to the MT to the target BTS over the RAN upon receipt of the second Handoff Request message.

9. A system for implementing a handoff in a mobile communication system in which at least two BSC (Base Station Controllers) are connected to at least two BTSs (Base Transceiver Systems) through a RAN (Radio Access Network), comprising:

an MT (Mobile Terminal) for transmitting to a target BTS a first Handoff Request message containing information about the MT when the MT moves to a handoff zone;

the target BTS for broadcasting a Search Request message for searching for an anchor BSC of the MT over the RAN upon receipt of the first Handoff Request message, transmitting to the anchor BSC a second Handoff Request message containing information about the target BTS and the MT information upon receipt of a Search Response message indicating the anchor BSC over the RAN, and providing a traffic service to the MT when a handoff is completed; and

the anchor BSC for transmitting a traffic signal directed to the MT to the target BTS upon receipt of the second Handoff Request message.