33 Years of the Digest ... founded August 21, 1981Copyright © 2015 E. William Horne. All Rights Reserved.The Telecom Digest for Mar 19, 2015
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| I do not like broccoli and I haven't liked it since I was a little kid and my mother made me eat it. And I'm President of the United States and I'm not going to eat any more broccoli. - George H.W. Bush |
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| Date: Mon, 16 Mar 2015 08:58:55 -0400 From: Jerry Feldman <gaf.remove-this@and-this-too.blu.org> To: telecomdigestsubmissions.remove-this@and-this-too.telecom-digest.org. Subject: Cell Network time no longer provided Message-ID: <5506D38F.9060206@blu.org> My mother complained that her phone time did not update to daylight savings time and she was told by AT&T that they no longer provide time on their network. This morning I got a notification on my Galaxy S5 that network time is not provided, switching to manual. Cell providers have been providing time forever. I think this is a quiet change at least by AT&T, but I'm sure it is with other networks also. -- Jerry Feldman <gaf.remove-this@and-this-too.blu.org> Boston Linux and Unix PGP key id:B7F14F2F PGP Key fingerprint: D937 A424 4836 E052 2E1B 8DC6 24D7 000F B7F1 4F2F |
| Date: Mon, 16 Mar 2015 09:46:10 -0400 From: Shirley Márquez Dúlcey <mark.remove-this@and-this-too.buttery.org> To: telecomdigestsubmissions.remove-this@and-this-too.telecom-digest.org. Subject: Re: Cell Network time no longer provided Message-ID: <CAMdng5uWe74+p7+FwwzXJM7KrLBEoA7GRZQME7-tUBQ-E4LhUQ@mail.gmail.com> On Mon, Mar 16, 2015 at 8:58 AM, Jerry Feldman <gaf.remove-this@and-this-too.blu.org> wrote: > My mother complained that her phone time did not update to daylight > savings time and she was told by AT&T that they no longer provide > time on their network. This morning I got a notification on my > Galaxy S5 that network time is not provided, switching to > manual. Cell providers have been providing time forever. I think > this is a quiet change at least by AT&T, but I'm sure it is with > other networks also. CDMA networks (Verizon, Sprint, and their MVNOs) are unlikely to make that change because they MUST have accurate time sources available at every cell site. Correct operation of the network requires that the sites be synchronized within milliseconds, because CDMA does soft handoffs as you travel. The network can reassemble partial reception from more than one site to piece together your conversation, and that requires that the timing be accurate. It's done by having a GPS time reference at each site. Since accurate time must be available in any case, they might as well continue to provide it to customers. T-Mobile, the other major GSM network in the US, still provides network time. |
| Date: Mon, 16 Mar 2015 10:36:55 -0400 From: Kent Borg <kentborg.remove-this@and-this-too.borg.org> To: telecomdigestsubmissions.remove-this@and-this-too.telecom-digest.org. Subject: Re: Cell Network time no longer provided Message-ID: <5506EA87.9010505@borg.org> On 03/16/2015 09:46 AM, Shirley Márquez Dúlcey wrote: > CDMA networks (Verizon, Sprint, and their MVNOs) are unlikely to make > that change because they MUST have accurate time sources available at > every cell site. They have to have precise timing to make CDMA soft-hand-off work, but does that necessarily translate into providing the civilian time information that the phone OS is looking for? "Time", in a physics sense, is pretty simple. Some cool relatively stuff, and questions about why it is unidirectional notwithstanding. But "time", in a civilian sense is complicated as hell: We want it to line up with contradictory celestial stuff and the changing whims of law makers on various levels of government and in various geographies. Providing precise phase information to CDMA isn't the same as knowing when daylight saving time begins. Might they have just dumped the civilian part? Remember, GPS time is now many seconds off of the seconds-portion of civilian time. Also, aren't the old GSM carriers now using updated protocols that are getting all spread spectrum on us? Do they need some of that precise timing coordination now, too? -kb |
| Date: Mon, 16 Mar 2015 10:51:15 -0400 From: Shirley Márquez Dúlcey <mark.remove-this@and-this-too.buttery.org> To: telecomdigestsubmissions.remove-this@and-this-too.telecom-digest.org. Subject: Re: cell Network time no longer provided Message-ID: <CAMdng5tawgdiY+yZb=PVd4P=QE-5==P8KTZrv+rgHpB0NF2JbQ@mail.gmail.com> On Mon, Mar 16, 2015 at 10:36 AM, Kent Borg <kentborg.remove-this@and-this-too.borg.org> wrote: > On 03/16/2015 09:46 AM, Shirley Márquez Dúlcey wrote: >> CDMA networks (Verizon, Sprint, and their MVNOs) are unlikely to make >> that change because they MUST have accurate time sources available at >> every cell site. > > They have to have precise timing to make CDMA soft-hand-off work, but does > that necessarily translate into providing the civilian time information that > the phone OS is looking for? > > "Time", in a physics sense, is pretty simple. Some cool relatively stuff, > and questions about why it is unidirectional, not withstanding. > > But "time", in a civilian sense is complicated as hell: We want it to line > up with contradictory celestial stuff and the changing whims of law makers > on various levels of government and in various geographies. > > Providing precise phase information to CDMA isn't the same as knowing when > daylight saving time begins. Might they have just dumped the civilian part? > Remember, GPS time is now many seconds off of the seconds-portion of > civilian time. > > Also, aren't the old GSM carriers now using updated protocols that are > getting all spread spectrum on us? Do they need some of that precise timing > coordination now, too? So far, US carriers are still using legacy protocols (GSM and CDMA) for voice calls and text messages. Higher speed protocols (HSDPA, HSPA+) are used for the data side by GSM carriers; CDMA carriers use EVDO. Both use LTE for their latest data offerings. They are starting to implement VoLTE (voice over LTE) as a replacement for legacy protocols but it will be years until the switch is complete. I don't know whether LTE includes any notion of time services; if not, the current notion of carrier-provided time will go out the window when LTE-only devices start to appear. But any LTE-capable device could easily synchronize to an NTP server on the internet if the OS includes that capability. So far as I know neither iOS nor Android currently does, though you can get third party apps to add automatic NTP synchronization to a rooted Android device. |
| Date: Mon, 16 Mar 2015 11:07:16 -0400 From: Kent Borg <kentborg.remove-this@and-this-too.borg.org> To: telecomdigestsubmissions.remove-this@and-this-too.telecom-digest.org. Subject: Re: Cell Network time no longer provided Message-ID: <5506F1A4.8030306@borg.org> I haven't checked it recently, but it used to be that when driving across Vermont on I-89 my Android GSM-style phone's time would jump several seconds as we entered the territory of some podunk wireless carrier, and jump back when returning the territory of a first world wireless carrier. -kb |
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