Method for performing hard hand-off in cellular mobile communication system

• US 20020107020A1
• Filed: 12/07/2001
• Published: 08/08/2002
• Est. Priority Date: 02/03/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jae-Duck
• Granted Patent: US 7,353,026 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node

Abstract

A method for performing a hard hand-off between service areas in a cellular mobile communication system is provided. The method for performing a hard hand-off according to the invention includes the steps of setting an area of services covered with a frequency assignment (FA) unavailable to adjacent stations to be a boundary cell, entering into the set boundary cell by a mobile communication terminal during communication, and searching FAs of adjacent stations excluding the base station currently engaged in communication with said mobile communication terminal so as to determine a target FA, with which the mobile communication terminal is to perform a hard hand-off. The method for performing a hard hand-off according to the invention can prevent deterioration of call qualities caused by unnecessary hard hand-offs, and reduce the load on a system.

Claims

1. A method for performing a hard hand-off in a cellular mobile communication system, the method comprising the steps of:

setting an area of services covered with a frequency assignment (FA) unavailable to adjacent stations to be a boundary cell;

entering into the set boundary cell by a mobile communication terminal during communication; and

searching FAs of adjacent stations excluding a base station currently engaged in communication with said mobile communication terminal so as to determine a target FA, with which the mobile communication terminal is to perform the hard hand-off.

2. The method of claim 1, wherein the target FA is determined by the mobile communication terminal through searching common FAs of adjacent stations to perform the hard hand-off therewith.

3. The method of claim 2, wherein determination of the target FA includes a step of recognizing that the mobile communication terminal is currently engaged in communication in the boundary cell, and commanding the mobile communication terminal to search FAs of the adjacent stations excluding the base station currently engaged in communication with said mobile communication terminal by means of a base station controller (BSC), which controls the hand-off of the mobile communication terminal.

4. A method for performing a hard hand-off in a cellular mobile communication system, the method comprising the steps of:

setting a service area covered with an FA unavailable to adjacent stations;

establishing a call in the set service area by a mobile communication terminal to initiate communication; and

searching FAs of adjacent stations excluding a base station currently engaged in communication with said mobile communication terminal so as to determine a target FA, with which the mobile communication terminal is to perform the hard hand-off.

5. The method of claim 4, wherein the target FA is determined by the mobile communication terminal through searching common FAs of adjacent stations to perform the hard hand-off therewith.

6. The method of claim 5, wherein determination of the target FA includes a step of recognizing that the mobile communication terminal is currently engaged in communication in a boundary cell, and commanding the mobile communication terminal to search FAs of the adjacent stations excluding the base station currently engaged in communication with said mobile communication terminal by means of a base station controller (BSC), which controls the hand-off of the mobile communication terminal.

7. A method for performing a hard hand-off in a cellular mobile communication system including at least two base stations for providing a mobile communication terminal with services by having service areas that share at least one FA and can be overlapped, and a base station controller (BSC) for controlling the hand-off of the mobile communication terminal, the method comprising the steps of:

setting an area of services covered by an FA unavailable to adjacent stations to be a boundary cell;

connecting communication with a first sector and a second sector by a softer hand-off while the mobile communication terminal moves from the first sector to the second sector of the base station currently engaged in communication with said mobile communication terminal;

recognizing the second sector to be the boundary cell, and commanding the mobile communication terminal to search common FAs of the adjacent stations, except the base station currently engaged in communication, by the BSC;

searching common FAs of the adjacent stations by the mobile communication terminal in response to the command, and reporting the searched results to the BSC;

determining a target FA, with which the BSC is to perform the hand-off by using the searched results if conditions for performing the hard hand-off are satisfied; and

performing the hard hand-off with the determined target FA by disconnecting the communication with the first sector and the second sector from the mobile communication terminal under a command of the BSC.