This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.
Harald Welte laforge at osmocom.orgHi Ivan, On Wed, Nov 11, 2020 at 01:26:01AM +0300, Ivan Babanov wrote: > After it we tried to use default config from master branch initially > created for RBS-2308. > It worked pretty fine except RF Power which was configured as 41dBm and 41 > - 12 = 29 dBm. Value 29 was not acceptable for our RBS. > I checked with Ericsson BSC Doc and found that our RBS2206 has max RF > output 47dBm for DCS1800. (btw, RBS2308 has only 34dBm max output according > to the same document, maybe config needs to be corrected) feel free to send a patch. > Looks like internal oscillator is not ready. So, the question is how to > make internal oscillator synchronized? Could it be an E1 Sync stability > issue caused by Digium cards? The question is not "could". Any BTS always needs a proper, stable reference clock. So unless your BTS has a built-in GPS clock refrence (and that reference is configured/enabled), your E1 will have to provide a stable clock reference. "stable" means (likely) fulfilling a clock stability that is _at the very least_ the stability of what commercial TDM/ISDN networks used to have. It doesn't hurt to have better stability. Any crystal oscillator on any E1/T1 peripheral card (digium or not) is by far not stable enough, possibly up to 1000 times worse than required. > 1. Set Digium card to get Sync from RBS. Now Digium is configured for > Internal clocking and acts as master. Maybe in case when both sides will be > configured to get sync from E1 it will decrease difference between internal > clock of RBS and E1 and RBS will get Synced state. And what would that get you to? In the end, a BTS that transmits at a frequency that will likely be so far off that you have serious problems connecting phones to it. > 2. Theoretically I can try to use Nokia DX200 BSC as a clock master for > Digium and deliver sync to RBS from Digium. I'm not sure if timing accuracy > is the same for Nokia and Ericsson HW. Sure, that should work. You can use any proper clock reference. One option I'm using here is to use a SIU-02. It has a 1PPS input for GPS, and it clocks up to 16 E1/T1 interfaces with that clock. You can then feed that clock signal to one port of your multi-port Digium card, and configure that as clock source, and the other ports will use that clock when talking to your BTSs. > One more question is where can I find some info about timing accuracy for > BTS and any possible way to check it on the existing E1 line? You would have to use some kind of test equipment that has a much more accurate/stable clock itself, like a rubidium oscillator or a GPS-DO. And then you can try to measure the Allan deviation/variance. But why do that? It's obvious that a normal crystal oscillator is way insufficient, no need to measure it. -- - Harald Welte <laforge at osmocom.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)