| 摘要 |
PROBLEM TO BE SOLVED: To provide a system for accurately determining the current location of a mobile subscriber unit, using data available in the existing CDMA system. SOLUTION: The system determines the geographic location of a subscriber unit within a CDMA communications system. At least one base station transmits a spread spectrum signal with a chip code sequence unique to that base station. A subscriber unit receives the base station signal and transmits a spread spectrum signal with a unique chip code sequence that is synchronized with the chip code sequence of the received base station signal. The base station receives the subscriber unit signal and compares the chip code sequence of the received subscriber unit signal with the chip code sequence signal transmitted by the base station, and specifies the location of the subscriber unit. COPYRIGHT: (C)2006,JPO&NCIPI |
