HANDOFF CONTROL METHOD AND A MOBILE STATION EMPLOYING THE SAME

• US 20100014484A1
• Filed: 09/25/2009
• Published: 01/21/2010
• Est. Priority Date: 11/01/1999
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakahara, Fumiharu, Chida, Yoshinori, Sudo, Shigeyuki, Asada, Yukinori
• Granted Patent: US 8,477,722 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

There is disclosed a handoff control method for registering a CDMA mobile station in such a way that battery power wastage is prevented if successive attempts to register the station fail. If it is judged that registration fails (step S106), idle handoff is inhibited (step S107). The mobile station shifts to a registration-waiting sleep mode (step S108 and state ST10) in which the sending and receiving operation of the mobile station is paused for a given time. When a sleep timer that is set in the step S108 times out, registration is resumed under certain conditions. On resumption, a new pilot signal is acquired.

Claims

1-7. -7. (canceled)

8. A mobile station comprising:

a receiver which receives a pilot signal transmitted by a sector;

a demodulator which demodulates the pilot signal received by the receiver; and

a controller which selects one of a plurality of sectors when the receiver receives a plurality of pilot signals from the plurality of sectors and executes a registration operation that includes a plurality of access sequence to the selected sector;

wherein when the mobile station fails in registration to the selected sector after the registration operations are performed a predetermined number of times, the controller executes the registration operation to a new sector different from the selected sector.

9. The mobile station according to claim 8, wherein the plurality of pilot signals are demodulated by the demodulator and the selected sector is selected based on a strength of the demodulated pilot signals.

10. The mobile station according to claim 8, wherein PN phases of the plurality of sectors are different from each other, and the new sector is selected by shifting a PN phase position from a PN phase position of the selected sector toward a phase advanced direction.

11. The mobile station according to claim 8, wherein the mobile station fails in registration to the plurality of sectors, the receiver pauses for a predetermined time.

12. The mobile station according to claim 8, wherein the mobile station fails in registration to the selected sector, the controller turns on an indicator to indicate that the mobile station is out of the coverage.

13. The mobile station according to claim 8, wherein the mobile station is used in a CDMA mobile communication system, and includes a CDMA modem which performs a dispreading demodulation operation of a signal transmitted by a sector.