SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Technology Stocks : Qualcomm Moderated Thread - please read rules before posting
QCOM 174.80+0.1%12:58 PM EST
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  
To: RoseCampion who wrote (23168)5/30/2002 12:08:48 AM
From: pheilman_  Read Replies (2) of 196641
 
Re: E-OTD technology.

This doesn't work so well, the problem is the base stations are sited for network connectivity rather than location. One big problem is called Geometric Dilution of Precision, GDOP, the worst case will be along a highway. The linear array of stations doesn't give additional information on the radius to the mobile. The best case is in a city with sites in all directions from a mobile. At least Cambridge Positioning Systems didn't try to claim this was new technology, differential time of arrival has been public domain for decades.

Love this quote "But in rural areas, cellular base stations are sometimes miles apart. Instead of four, it's likely there will be just two base stations to help figure out the location, making it less accurate, Wade said." Visualize the mobile and both base stations as colinear. All this system can determine is which direction the mobile is from the base stations, it cannot make any statement about where the mobile is along the road, this is the worst case for the system and it is very common in rural settings with the base stations along the major highway, 'coz that's where the mobiles operate. Less accurate in this quote means really useless. Unless the TDM system is keeping track of the absolute delay to the mobile to a sub-microsecond accuracy, they will never pass the requirement.

Wish I could suggest some test cases for their FCC approval testing.

Paul
Report TOU ViolationShare This Post
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  

HomeMailHotSubjectMarksPeopleMarksKeepersSettings
Terms Of UseContact UsCopyright/IP PolicyPrivacy PolicyAbout UsFAQAdvertise on SI
© 2025 Knight Sac Media.  Data provided by Twelve Data, Alpha Vantage, and CityFALCON News