Wireless communication terminal and handoff judgment method

• US 20060035638A1
• Filed: 12/10/2003
• Published: 02/16/2006
• Est. Priority Date: 12/10/2002
• Status: Active Grant

• Current Assignee: GE Technology Development Incorporated (General Electric Company)
• Original Assignee: Kyocera Corporation
• Inventors: Hidaka, Hiroyuki
• Granted Patent: US 7,233,793 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A wireless communication terminal, which performs wireless communication with base stations using each of a first communication method and a second communication method and enables to in an idle state with both methods, having a measurement section that measures quality of a signal transmitted from the base station, a handoff determination section that determines handoff in an idle state with the second communication method based on quality of signals transmitted from a connected base station and another base station, and a control section that changes a criterion of the determination of the handoff in the idle state with the second communication method in accordance with a state of the first communication method.

Claims

1. A wireless communication terminal, which performs wireless communication with base stations using each of a first communication method and a second communication method and enables to be in an idle state with both methods, comprising:

a measurement section that measures quality of a signal transmitted from the base station;

a handoff determination section that determines handoff in an idle state with the second communication method based on quality of signals transmitted from a connected base station and another base station; and

a control section that changes a criterion of the determination of the handoff in the idle state with the second communication method in accordance with a state of the first communication method.

2. The wireless communication terminal according to claim 1,

wherein the control section sets a first determination threshold value to be used for determining handoff during the idle state with the second communication method when the first communication method is in an idle state, and sets a second determination threshold value to be used for determining handoff during the idle state with the second communication method when the first communication method is in communication.

3. The wireless communication terminal according to claim 2,

wherein the control section sets the second determination threshold value such that frequency of handoff with the second communication method decreases as compared with that of the first determination threshold value.

4. The wireless communication terminal according to any one of claims 1 to 3,

wherein the first communication method is a 1×

EVDO system, and the second communication method is a cdma2000 1×

system.

5. A handoff determination method of a wireless communication terminal which performs wireless communication with base stations using each of a first communication method and a second communication method and enables to be in an idle state with both methods, the handoff determination method comprising the steps of:

changing a handoff determination criterion of the second communication method in accordance with a status of the first communication method; and

determining handoff with the second communication method based on the changed handoff determination criterion.

6. The handoff determination method according to claim 5,

wherein a first determination threshold value to be used for determining handoff during an idle state with the second communication method is set when the first communication method is in an idle state, and a second determination threshold value to be used for determining handoff during the idle state with the second communication method is set when the first communication method is in communication.

7. The handoff determination method according to claim 6,

wherein the second determination threshold value is set such that frequency of handoff with the second communication method decreases as compared with that of the first determination threshold value.

8. The handoff determination method according to any one of claims 5 to 7,

wherein the first communication method is a 1×

EVDO system, and the second communication method is a cdma2000 1×

system.