Data Rate of EGPRS is Too Low

Matthew Johnson matt9j at cs.washington.edu
Wed Apr 4 16:54:43 UTC 2018


Hello Xinke,
I'm a graduate student at the University of Washington, and just brought up
an EGPRS/GPRS network with an Ettus B210/osmo-trx. My B210 has a GPSDO as
well. I'm just getting started on this project (so I'm unfortunately not
the expert you are looking for), but I can corroborate that I am also
seeing very limited single user throughput in EGRPS and vanilla GRPS
(6-8kbps maximum measured via iperf). My network is built with the latest
split components running on a debian9 virtual machine via virtualbox. I'll
attach my configs here if they're helpful. I also have access to a
litecell1.5 and will be bringing up the network on it in the next few
weeks, so I'll be able to report if it behaves any better. The litecell
setup will also be running on dedicated hardware to rule out any
strangeness from virtualbox. Sorry I don't have any other clues at this
time, but I can at least confirm Neels's analysis above and rule out the
impact of running the old nitb and ggsn.
Cheers,
-Matt Johnson

On Mon, Mar 5, 2018 at 2:15 PM, Neels Hofmeyr <nhofmeyr at sysmocom.de> wrote:

> On Sat, Mar 03, 2018 at 12:18:52PM +0000, XINKE ZHANG wrote:
> > I'm sure that B210 has a GPSDO. I execute 'uhd_usrp_probe' to prove it.
>
> I'm not familiar with it, but if you say so.
>
> > My entire config files are attached here. Pls help check it. Thanks.
>
> It all looks good to me. Two minor notes:
>
> - the pcu config once needed 'two-phase-access' to function reliably, but
> this
>   is no longer needed.
>
> - you seem to be running an old version of the ggsn. The new one is called
>   osmo-ggsn with a config file style and vty interface like the other osmo
>   programs. However, this should not affect your downlink throughput.
>
> - you also seem to run osmo-nitb, we have moved to separate programs, being
>   osmo-hlr, osmo-msc and osmo-bsc. Refer to
>   http://osmocom.org/projects/cellular-infrastructure/wiki/
> Osmocom_Network_In_The_Box
>   This should, however, not affect your downlink throughput, either.
>
> So yeah, sorry, but I have nothing of weight to add. Maybe someone else
> here
> has deeper knowledge of EGPRS and SDR based BTS?
>
> ~N
>
>
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