| 摘要 |
<p>A method and apparatus for providing a reliable means to perform handoff from a code division multiple access (CDMA) system using a pilot signal to an alternative access technique system. Simple pilot box circuitry (350) is added to a set of border base stations (C2A-C2R). The border base stations are base stations (C2A-C2R) which operate only in the alternative access technique and which have coverage areas which are contiguous with coverage areas of CDMA operation base stations (C1H-C1S). The mobile unit (10) monitors for the pilot signal from the border base stations (C2A-C2R) in the same manner as it monitors for pilot signals from the CDMA operation base stations (C1A-C1S). When the mobile unit (10) detects the pilot signal corresponding to a border base station (C2A-C2R), it notifies a system controller (202) in accordance with standard operation. The system controller (202) is aware that the pilot signal corresponds to a border base station and thus triggers a hard handoff process to the alternative access technique system in response thereto. The border base stations (C2A-C2R) use a time division duplex technique to monitor a pilot and synchronization sequence from a neighboring one of the CDMA operation base stations to obtain an estimate of absolute system time.</p> |
