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Sylvain Munaut 246tnt at gmail.comHi,
> = audio broadcast =
>
> [snip]
>
> The question is: Is it worth it? Are people really listening to
> lectures using GSM (bad quality, ...)? And if yes, should we simply
> disable this feature on GSM to make room for more important stuff?
People are definitely using it and I think it's a perfectly valid use
case and we should not block it (at least not comlpetely. We could for
example block it is our last TCH for eg). Quality is not always the
best, but speaking from experience, bad english audio is more
understandable than german.
I think that although it'd be a nice hack, other solutions could be
better and handle more use case :
- Use of TCH/H with AMR-HR
- Smaller cell
- Multi TRX
> = network structure / capacity =
>
> To increase capacity, we can either get our hands on hardware with many
> more TRX, or we can reduce the cell size and deploy more sysmoBTS 1002.
> The latter would definitely be possible from the sysmocom point-of-view.
> The former would mean that we can obtain a sufficient number of
> multi-TRX BTSs.
>
> If we make smaller cells, this would mean that the BTSs would be
> * PoE powered
> * have no PA/LNA
> * operate with reduced tx power (20mW?) and high rxlev_access_min
> * use directly attached small rubber antennas
>
> I like that approach as it simplifies the setup. No power supplies, no
> antenna cabling, no large wooden boards, ... - it would in the end be
> very similar to the the wifi APs or the DECT 'antennas'.
>
> Any thoughts?
Smaller cells to offload busy areas is definitely the way to go IMHO,
but I wouldn't drop the large cells all together.
The CCH is rather large and covering all corners of it with small low
power cell would not be that easy especially frequency planning when
the propagation changes quite drastically between an empty venue and
one with 9k people in it ...
Also, there isn't PoE everywhere. This years they had quite a variety
of switches, some with PoE, some with PoE+ and some with nothing so
each time we either need to find power or we'd need to put injectors
(which requires access to the patch room which would need more NOC
coordination and even then AFAICT some of them are only accessible
with the help of CCH staff).
So I'd probably go for 3 large cells (one of them in the MOC, easier
to setup stuff there) and the two others at opposite end of the CCH on
different floors, or in the middle (like the one we put in with the
bidirectional patch). Then the rest small cells distributed in the
crowded areas (main halls + hackcenter + lounge mainly) becasue it's
true it's very practical. The cell we had in the catwalk/balcony above
Hall 3 was really simple to install/remove. I also wouldn't bother
with nanoBTS at all, we haven't used them this year at all and it was
really stable on day 2,3,4 once we fixed that nasty SMS bug.
We'd need to review the logs to see which BTS experienced the more "No
free channel" messages.
I also think multi-TRX could be fun (possibly using fairwaves HW), but
we can run out of ARFCN easily. It would be nice if we could sync the
L1 of the BTS and use "shared ARFCN" where for eg one TS is used by
one BTS and another for another BTS (dynamically of course so the
capacity self-adapts).
Cheers,
Sylvain