METHOD AND APPARATUS FOR MEASUREMENT DIRECTED HARD HANDOFF IN A CDMA SYSTEM

摘要

In a communications network, a network user communicates using a remote unit (125) with another user (30) via at least one base station (B1A). The network is comprised of first (MSC-I) and second (MSC-II) mobile switching control stations respectively controlling communications through a first set of base stations (B1A-B1E) including a first base station (B1A) and through a second set of base stations (B2A-B2E) including a second base station (B2A). To direct communications between the remote unit (125) and the first (B1A) and second base stations (B2A) the first base station (B1A) measures a round trip delay of an active communication signal between the first base station (B1A) and the remote unit (125). The remote unit (125) measures a first phase offset of a pilot signal received from a first candidate base station (B1A) and reports it to the first mobile switching center (MSC-I) via the first base station (B1A). The first mobile switching center (MSC-I) calculates a candidate round trip delay between the remote unit (125) and the first candidate base station (B1A) based on the first phase offset and the round trip delay of the active communication signal. An active communication control unit accesses a measurement directed hard handoff table to determine a location of the remote unit based on the round trip delay corresponding to the first active communication signal and the candidate round trip delay.