Bug #3055
closed
- Related to Feature #1851: generalize power control and TA loop code added
- Related to Bug #2988: unexpected bit errors when using trxcon and osmo-bts-trx added
- Assignee changed from 4368 to tnt
Yes, it's slow. But OTOH it can cope with at least 1 TA value every 2 second, so that's a MS moving at ~ 1000 km/h. The way it's implemented now, it's basically heavily dampened which means it should also be very stable.
An alternative is to make the step proportional to the toa difference, basically reducing the time to adapt.
Instead of doing +1 we'd do + (toa * alpha) alpha being the damped factor. The closer alpha is, the faster it's going to react but also the more it can oscillate in case of measurement noise.
Thoughts ? Is this really an issue ?
- Priority changed from Normal to Low
Yes, it's slow. But OTOH it can cope with at least 1 TA value every 2 second, so that's a MS moving at ~ 1000 km/h.
Hmm, you're right. GSM TS 05.10 says: "The control loop for the timing advance shall be implemented in such a way that it will cope with MSs moving at a speed up to 500 km/h", so the current implementation is compliant.
An alternative is to make the step proportional to the toa difference, basically reducing the time to adapt.
Thoughts ? Is this really an issue ?
Are there any other cases when the TA value rapidly changes and we need to react quickly?
If no, feel free to close this issue. Changing priority to low for now.
Hi Sylvain,
On Mon, Jan 21, 2019 at 03:36:46PM +0000, tnt [REDMINE] wrote:
Yes, it's slow. But OTOH it can cope with at least 1 TA value every 2 second, so that's a MS moving at ~ 1000 km/h. The way it's implemented now, it's basically heavily dampened which means it should also be very stable.
Indeed, you're making a very valid point. I don't think we need to react too quickly to large changes,
because something fishy is going on in such cases.
Thoughts ? Is this really an issue ?
I wouldn't think so.
- Status changed from New to Closed
Ok, closing. Thank you Sylvain!
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