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Technology Stocks : Qualcomm Moderated Thread - please read rules before posting -- Ignore unavailable to you. Want to Upgrade?

To: pheilman_ who wrote (23222)	5/30/2002 11:53:34 PM
From: rkral	Read Replies (1) \| Respond to of 196649

GSM is not very good for doing RF triangulation. It is narrowband. Imho, the 200 kHz BW is probably not as limiting as you think. Back to this later. .. a method for RF timing .. is to time off a transmitted timing pattern, still limited by the BW. Something similar to this for EOTD is very plausible to me. It's probably as simple as reading an accurate clock at a certain point in the data frame, or super-frame. BTW, the BTS is the transmitting device when the EOTD measurements are taken. It is not the mobile, as you stated. This is confirmed in the white paper noted below .. and mightylakers says the same. Your bandwidth point is well-taken, but this is effectively neutralized by reading the clocks in both the mobile and a reference device (a Location Measurement Unit, LMU) discussed on both the CPS (Cambridge PS) site and in a SnapTrack white paper. cdmatech.com The difference in these two clock readings is then used to calculate the distance from the BTS to the mobile. Of course, the relative time difference between the clocks must be known, as well as the distance from the BTS to the LMU. If the receiver BW of the mobile and the LMU are essentially identical, the impact of the narrow bandwidth should be minimal, imo. Ron