Method and apparatus for location finding in a CDMA system
US5508708A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1995 |
| Grant date | Apr 16, 1996 |
| Priority date | — |
| Expiry date | May 8, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/145
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.