Patent ID: 6597673
Filing Date: 2003-07-22
Classification: H04W

Abstract:
A soft handoff control method by a base station controller in a CDMA mobile telecommunications system in which, when a mobile station is handed off to a wireless link with another base station, handoff to a prescribed wireless link is performed after wireless links are established between the mobile station and a plurality of base stations simultaneously, comprising the steps;dividing a cell into a cell perimeter area, one or more cell intermediate areas and a cell center area and inputting an area ratio to the base station controller; setting some levels of reception electric field strength that are used for deciding the mobile station exists in which area so that the base station controller performs soft handoff control at the cell perimeter and the cell intermediate areas; deciding a number of soft handoff branches in each area based upon said area ratio; receiving from the mobile station, a reception electric field strength of radio waves from said another base station; discriminating an area in which the mobile station is situated by comparing the received reception electric field strength and the set levels; determining, based upon the discriminated area, the number of soft handoff branches allocated to said mobile station; and performing soft handoff control based upon the number of soft handoff branches.