Other Wireless Technology
Geo-location methods used for non-critical applications.
When the application does not require pinpoint accuracy, there are other geo-location methods that may be used to complement high-accuracy location methods.
O-TDOA: Observed Time Difference of Arrival
The accuracy performance for O-TDOA degrades in non-line-of-sight conditions and is only slightly better than a solution like Enhanced Cell ID (ECID) discussed below. O-TDOA has not been commercially deployed to date, except for its use as a fallback technology in CDMA2000.
ECID: Enhanced Cell ID
ECID solution uses cell tower location, distance from cell sector (timing advance) and in some cases signal strengths. ECID provides medium accuracy performance on the order of 1/8th of the cell coverage area. The accuracy provided is marginally better than Cell-ID or Cell-ID+Timing methods.
CID +TA: Cell ID + Timing Advance
CID+TA solution uses cell tower location and distance from cell sector (timing advance (TA), round trip time (RTT) or other time delay) to determine mobile location. CID+TA provides low accuracy performance and in the order of 1/4th of the cell coverage area. CID+TA performance is only slightly better than Cell ID and hence is used for some non-demanding commercial applications only.
CID: Cell ID
CID solution uses cell tower location to determine mobile device location. CID is available as an inherent part of the operator’s network.