UmTRX March 2013

umtrx@lists.osmocom.org

11 participants
20 discussions

OpenSIPS Was: transceiver won't start; fpga build error

by Alexander Chemeris

Hi Stephane, On Wed, Mar 6, 2013 at 4:20 AM, <stephane(a)shimaore.net> wrote: >> Thank you for your patch to make it working with OpenSIPS :) Looking >> forward for more contributions to the SIP side of things. > > My line of thought is to use OpenSIPS as registrar, with a Redis > backend. Then use OpenSIPS to route calls, SMS, .. based on the IMSI. It seems that using OpenSIPS as much as possible is a good way for scalability, instead of trying to get Freeswitch to scale. At least that's what I was suggested. So I wonder what we could actually offload to OpenSIPS. Do you think we could use OpenSIPS not only as a registrar, but also as an authentication server? And what do you think about routing calls with it? I was told that the best way to get it to scale is to use static routing, i.e. without an access to an external DB. But now the problem is that subscribers move from a BTS to a BTS and it can't be completely static. One solution is to actually have Location Areas as in GSM and use broadcasted SIP INVITEs in them. Or alternatively we could do some "virtual LA" on SIP level by creating a layered set of OpenSIPS instances. SMS is another issue, because it requires a "store and forward" server. Did you know an existing solution for that? Or is it easier to just write the thing from scratch :) -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

12 years, 3 months

sendsms with CLI

by Craig Reading

Workaround implemented by Ivan working fine for me now. sendsms is much more reliable. Thanks Ivan >>> We were recently looking into a bug when MT-SMS delivery was interrupted with an unexpected UA frame on L2 layer. We've fixed this in our branch by ignoring a second UA in Established L2 state [1], but the real issue lies in the filler table coupled with delays in processing in higher layers.

12 years, 3 months

Re: Sendsms using cli

by Craig Reading

Joel, I have played with sendsms and the results seem hit and miss. Sometimes OpenBTS core dumps. After a power cycle of my Nokia MS the first SMS is received OK e.g. sendsms 234100516180928 SabreTek Hello with a Wireshark trace showing: GSM SMS 87 I, N(R)=0, N(S)=1(DTAP) (SMS) CP-DATA (RP) RP-DATA (Network to MS) The next SMS does not get received and I see the following error in the OpenBTS logs: GSML2LAPDm.cpp:925:sendMultiframeData: obj: 0x8b14078 attempt to send DATA on released LAPm channel I would up the log level on GSM L2 and continue investigations here. config Log.Level.GSML2LAPDm.cpp DEBUG PS: You can clear the TMSI table using the following SQL in a file named "TMSI.sql": BEGIN TRANSACTION; DELETE FROM TMSI_TABLE; COMMIT; Then: sqlite3 -init TMSI.sql /etc/OpenBTS/OpenBTS.db ".quit" Regards Craig

12 years, 4 months

by Emmanuel Aposaz

hi i want the umtrx module for test. Where can i order it. i hope to have the help of the community if after i get problem whith configuration. Is the module come with antenna and daughterboaders or i have to order it also?

12 years, 4 months

UmTRX is Alive (again!)

by Craig Reading

After rebuilding everything on a new server with Ubuntu 12.04 my UmTRX test setup now seems to be rock solid. http://genesysguru.com/blog/blog/2013/03/23/umtrx-is-alive-again/ Regards Craig

12 years, 4 months

Re: Fwd: UmTRX Digest, Vol 9, Issue 16

by Alexander Chemeris

This is pure host side UHD update (UHD driver as you call it). Sent from my Android device. -- Regards, Alexander Chemeris CEO, Fairwaves LLC http://fairwaves.ru 20.03.2013 16:47 пользователь "Craig Reading" <craig.reading1(a)gmail.com> написал: > Alexander > > Is this a firmware update or UHD driver update? If firmware would it be > possible to upload an image? > > Regards > Craig > > Begin forwarded message: > > *From:* umtrx-request(a)lists.osmocom.org > *Date:* 19 March 2013 20:36:34 GMT > *To:* umtrx(a)lists.osmocom.org > *Subject:* *UmTRX Digest, Vol 9, Issue 16* > *Reply-To:* umtrx(a)lists.osmocom.org > > Send UmTRX mailing list submissions to > umtrx(a)lists.osmocom.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.osmocom.org/cgi-bin/mailman/listinfo/umtrx > or, via email, send a message with subject or body 'help' to > umtrx-request(a)lists.osmocom.org > > You can reach the person managing the list at > umtrx-owner(a)lists.osmocom.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of UmTRX digest..." > > > Today's Topics: > > 1. Tx signal quality improvement (Alexander Chemeris) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 20 Mar 2013 00:33:29 +0400 > From: Alexander Chemeris <alexander.chemeris(a)gmail.com> > To: umtrx <umtrx(a)lists.osmocom.org> > Subject: Tx signal quality improvement > Message-ID: > <CABmJbFV4C0_WBCBuj61U8_2bQjm9x049ciB0yYQDjJdoHxiNGg(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi all, > > I've found an issue with out Tx configuration of LMS which led to > constant phase rotation of the transmitted signal. After fixing this > issue I get quite better signal quality on transmit side. I advise > everyone to update to the most recent UHD on the host side to benefit > from this improvement. > > The reason for the issue was that we used the wrong polarity of TX_ > IQ_SEL. As a result, LMS transmitted I from one sample and Q from the > other sample. One of the visible results was a huge I/Q imbalance on > Tx which made it impossible to use multi-ARFCN configurations. We've > solved this issue in software by setting tx_fsinc_polarity and > tx_interleave_mode to proper values in LMS configuration registers. > > Attached screenshots from our E4406A shows signal quality transmitted > by OpenBTS we could have now. Tests are performed with "laurent" > branch of Fairwaves, compiled with SPS (samples per symbol) set to 4. > DC offset and I/Q imbalance are calibrated. > > screen2.gif, screen3.gif - constellation and phase error when LO > leakage is at the center of the signal spectrum, i.e. with no LO > offset on Tx. > > screen4.gif, screen5.gif - constellation and phase error when DC > offset is when LO leakage is shifted to 300kHz away from the signal > spectrum center, i.e, with 300kHz LO offset on Tx. > > screen6.gif - phase error per symbol plots for the same settings as > with screen4.gif and screen5.gif. > > When we implement a true GMSK transmitter we should be able to get > even better phase noise parameters, meaning excellent downlink signal > quality. But even this values are much better than required by the > Standard. > > -- > Regards, > Alexander Chemeris. > CEO, Fairwaves LLC / ??? ??????? > http://fairwaves.ru >

12 years, 4 months

Tx signal quality improvement

by Alexander Chemeris

Hi all, I've found an issue with out Tx configuration of LMS which led to constant phase rotation of the transmitted signal. After fixing this issue I get quite better signal quality on transmit side. I advise everyone to update to the most recent UHD on the host side to benefit from this improvement. The reason for the issue was that we used the wrong polarity of TX_ IQ_SEL. As a result, LMS transmitted I from one sample and Q from the other sample. One of the visible results was a huge I/Q imbalance on Tx which made it impossible to use multi-ARFCN configurations. We've solved this issue in software by setting tx_fsinc_polarity and tx_interleave_mode to proper values in LMS configuration registers. Attached screenshots from our E4406A shows signal quality transmitted by OpenBTS we could have now. Tests are performed with "laurent" branch of Fairwaves, compiled with SPS (samples per symbol) set to 4. DC offset and I/Q imbalance are calibrated. screen2.gif, screen3.gif - constellation and phase error when LO leakage is at the center of the signal spectrum, i.e. with no LO offset on Tx. screen4.gif, screen5.gif - constellation and phase error when DC offset is when LO leakage is shifted to 300kHz away from the signal spectrum center, i.e, with 300kHz LO offset on Tx. screen6.gif - phase error per symbol plots for the same settings as with screen4.gif and screen5.gif. When we implement a true GMSK transmitter we should be able to get even better phase noise parameters, meaning excellent downlink signal quality. But even this values are much better than required by the Standard. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

12 years, 4 months

No ARP reply

by Craig Reading

Moved UmTRX on to 192.168.11.10 and get no ARP reply. I'm probably being dumb! Just wanted to make sure there is no issue with subnet mask etc. Regards Craig

12 years, 4 months

UHD dissector for Wireshark

by Alexander Chemeris

Hi all, I apologize for cross-posting. Please reply to the mailing list you're subscribed to. Ivan Kluchnikov and I wrote a simple dissector for UHD-over-IP control streams. We use it to debug UmTRX which is using UHD under the hood, but I thought it might be useful for a wider USRP community. Patches are as usual welcome. Source code: https://github.com/chemeris/uhd_dissector -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

12 years, 4 months

Re: UmTRX performance questions

by Alexander Chemeris

On Fri, Feb 22, 2013 at 6:28 PM, joel yabut <joel(a)jointventure.com> wrote: > May i know the following specs > 1. What is the tx and rx isolation of umtrx? > 2. What is the power output in dbm of your umtrx? Andrey Sviyazov will comment on this. > 3. How is the lna on the rx input and is an external lna and bpf > recommended? For Fairwaves 10W base stations we're developing UmSEL, which has channel filter and an additional LNA. For the use without amplifier you don't need any additional filters or LNAs. > 4. What is the main advantage of umtrx compared to usrp by ettus? If you want to use it for GSM, then it's cheaper and gives you dual-channel support. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

12 years, 4 months

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UmTRX March 2013