Hi gentelmen,
I apologise for this very comment. -----Original Message----- From: ofono-boun...@ofono.org [mailto:ofono-boun...@ofono.org] On Behalf Of Marcel Holtmann Sent: Friday, November 05, 2010 9:47 PM To: ofono@ofono.org Cc: Ahmed, Suhail Subject: RE: [RFC 1/3] doc: addidng documentation for basic assisted gps > > > > + void RequestFineTimeInjection(string rat, uint16 pulselength) > > > It seems to me that making the upper layers pass in the rat as a > > > parameter to this function is a pretty bad idea. You should either have > > > the atom figure this out if it can (e.g. by using netreg atom) or have > > > the driver take care of this directly. > > > > I was asked to add it as the AGPS manager that makes the request presumes > > a certain RAT and there is no point in generating the pulse if the RAT has > > changed since. > > See also http://lists.ofono.org/pipermail/ofono/2010-May/002347.html > Seems still wrong to me. Why would an application have to deal with > this. This looks like an internal implementation detail to me. Pushing > such a thing out to the application is against the philosophy of our > D-Bus APIs to simplify things. The fine time injection consists in generating a hardware pulse for the GPS device at the beginning of a radio frame. Thanks to assistance data received from the 3GPP network or SUPL, the Position framework (or the GPS manager) knows the link between the Universal Time and the radio frame number. It allows the position framework to determine the Universal Time with a pretty good accuracy ( a few micro seconds). The GPS system being time based, the precise knowledge of the Time allows a faster acquisition of the position (a faster TTFF, time to first fix). Another usage, allowing also to achieve a faster TTFF, is to provide a precise time reference to the GPS device by using the length of the pulse (usually a radio frame). A dual mode modem is synchronized on both 3G and 2G networks so you have to specify to the modem if the pulse must be generated at the beginning of a GSM TDMA frame or at the beginning of a 3G CDMA frame. The two systems do not use similar radio frame structures. I hope it clarifies a bit the purpose of this RAT field. BR, Fred --------------------------------------------------------------------- Intel Corporation SAS (French simplified joint stock company) Registered headquarters: "Les Montalets"- 2, rue de Paris, 92196 Meudon Cedex, France Registration Number: 302 456 199 R.C.S. NANTERRE Capital: 4,572,000 Euros This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
_______________________________________________ ofono mailing list ofono@ofono.org http://lists.ofono.org/listinfo/ofono
