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1. (WO1998053620) BOUNDARY SECTOR HARD HANDOFF TRIGGER

Pub. No.:    WO/1998/053620    International Application No.:    PCT/US1998/009132
Publication Date: Fri Nov 27 00:59:59 CET 1998 International Filing Date: Wed May 06 01:59:59 CEST 1998
IPC: H04W 36/14
Applicants: NORTHERN TELECOM LIMITED
BOETTGER, David
JALALI, Amhad
Inventors: BOETTGER, David
JALALI, Amhad
Title: BOUNDARY SECTOR HARD HANDOFF TRIGGER
Abstract:
A method and system for triggering hard handoff of a call from a CDMA network cell operating on a first frequency to a cell operating on at least one second frequency or in an AMPS network are disclosed. In a departure from the art, a boundary sector handoff trigger is implemented in two stages. The first stage of the trigger occurs when the active set of a mobile unit consists only of pilots identified as boundary pilots; that is, the active set comprises a 'boundary active set.' Once the requirements for the first stage are satisfied, a second stage of the boundary sector trigger of the present invention is enabled. During the second stage, a round-trip delay ('RTD') of communications between the mobile unit and the BTS to which it is nearest is monitored and once the RTD exceeds a predetermined threshold, the trigger is complete and handoff processing continues with target selection and handoff execution.