Yes, USA GSM/UMTS operators also use GPS at their base stations. They may use it for timing, but I think the primary requirement for it comes from E911 support, and maybe to provide AGPS and/or clock-setting support for phones.
European and Asian operators often do without it (they typically won't set the time on your phone either). I know of more than a few countries which in fact have national regulatory constraints against relying on GPS for anything important. The base stations still need a frequency reference, but they can generally get that by recovering the clock from the transmission circuit which connects the base station to the rest of the network. Dennis Ferguson On 19 Dec, 2011, at 16:22 , [email protected] wrote: > I was inside a AT$T shack about a month ago. They have GPS timing inside. I > took some photographs, so I will dig up later what timing they use. > > -----Original Message----- > From: Dennis Ferguson <[email protected]> > Sender: [email protected] > Date: Mon, 19 Dec 2011 14:00:29 > To: Discussion of precise time and frequency measurement<[email protected]> > Reply-To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Another Trimble Thunderbolt-like GPS? > > > On 19 Dec, 2011, at 11:25 , Rob Kimberley wrote: > >> There was a spec issued many years ago to the industry from Lucent I believe >> to come up with a GPS product for base station requirements. 10 MHz, 1PPS, >> OCXO, RS-232 port, and a certain holdover spec. The Thunderbolt was one, >> Starloc another, NanoSync (from Odetics/Zyfer). There were others. >> >> Rob Kimberley > > I think it was actually Qualcomm. The requirement for GPS time and 10 > microsecond > time synchronization (which informs the holdover spec) came from Qualcomm's > CDMA > specification and are unique to it. GSM, UMTS and (I think) LTE base > stations can > get by without GPS at all. > > Dennis Ferguson > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
