[srslte-users] Help with srsUE

Thu Feb 2 16:00:31 UTC 2017

On the srsUE side using a B210:
tx_gain = 82
rx_gain is commented out for AGC

Amarisoft side using a B210:
tx_gain = 89
rx_gain = 30 (I don’t know if Amarisoft has a AGC or if it’s possible to used UHD’s AGC)

Unfortunately, I don’t know how to get srsUE to transmit continuously to tune it.
I was fortunate to have the Nutaq PicoSDR with Amarisoft and working configs preloaded. I connected the Nutaq box with srsUE and performed a iperf uplink test to get continuous tx from srsUE for measuring power output and tuning. I know you have yet to get srsUE working with Amarisoft or OAI, so you may not be able to do the same. Hopefully someone else can answer that question? You could always try my settings as a starting point and adjust them as needed?

Pat

From: Emilie Meyer [mailto:emiliemeyer1016 at gmail.com]
Sent: Thursday, February 02, 2017 9:24 AM
To: Patrick Cutno <PCutno at girdsystems.com>
Cc: srslte-users at lists.softwareradiosystems.com
Subject: Re: Help with srsUE

Hi Patrick

Thx for your very useful information. I am still working on with the tuning of tx and rx gain.
The measuring of eNB the signal strength was quite easy as the eNB is sending more or less continuously.

The situation is not the same on the ue side, as the transmissions are very short and few.
Is there a way to make the ue side transmit continuously for tuning purposes.

Just wonder what are your current tx and rx gain settings on amarisoft and srsue, when using the 40 dB attenuator in between?

Regards

Em

On Wed, Feb 1, 2017 at 5:23 PM, Patrick Cutno <PCutno at girdsystems.com<mailto:PCutno at girdsystems.com>> wrote:
Emilie,

Just an update, I have mentioned before that my Amarisoft eNB is running on a Nutaq PicoSDR 4x4 and I have been trying to get it to work a B210. . . I just got that to work.

  1.  An old version of UHD had to be used (sorry but a coworker set that up for me so I don’t have instructions for this)
  2.  Amarisofts ‘launch_enb.sh’ had to be modified to specifically call the older version of UHD not the newer one I already had installed

srsUE has always worked perfectly with Amarisoft on the Nutaq box. When I put the Amarisoft stack on a different computer that used a B210, I was getting a lot of link failures but I knew it wasn’t srsUE’s fault. Using the setup previously described to reduce the number of variables, I was able to tune the eNB’s tx gain to output somewhere between -10 to 0 dBm (before attenuation) and adjust the rx gain up and down until I got a solid connection. Amarisoft’s default rx gain defined by the single channel rf driver for the B210, turns out to be too high. I came to the conclusion that the high rx gain actually hurt the signal and Amarisoft’s terminal agreed by reporting really bad uplink SNR. By significantly reducing the eNB rx gain, I was able to improve the uplink SNR with srsUE and get a solid connection with no link failures.

I am still getting underflows and late messages on the eNB B210 but I will continue to look into it and maybe use a N210 instead.

Pat

From: Patrick Cutno
Sent: Wednesday, February 01, 2017 10:06 AM
To: 'Emilie Meyer' <emiliemeyer1016 at gmail.com<mailto:emiliemeyer1016 at gmail.com>>
Cc: 'srslte-users at lists.softwareradiosystems.com<mailto:srslte-users at lists.softwareradiosystems.com>' <srslte-users at lists.softwareradiosystems.com<mailto:srslte-users at lists.softwareradiosystems.com>>

Subject: RE: Help with srsUE

Emilie,

I am using SISO.
And you’re welcome, hopefully you can figure out your issue if it is a RF problem.

Pat

From: Emilie Meyer [mailto:emiliemeyer1016 at gmail.com]
Sent: Wednesday, February 01, 2017 9:02 AM
To: Patrick Cutno <PCutno at girdsystems.com<mailto:PCutno at girdsystems.com>>
Subject: Re: Help with srsUE

Hi Patrick

I highly appreciate that you share your experience and knowledge.
I will do the suggested modification today.

BTW, do you use SISO or MIMO on your Amarisoft?

> I don’t have an explanation of why a COTS device works fine wirelessly, but the setup above helped me pinpoint my RF problem with minimal variables to consider.

Maybe some experts could help clarify this issue, why a COTS UE can communicate with eNB at 10-15 meters distance without problem, while an SDR based UE cannot, even when the distance is only 1-2 meters.
It makes no sense to me that a COTS UE with limited resources can do it better than an SDR based UE with much more resources. A guess is that this issue is related to the configuration of tx/rx parameters on srsUE side?

> I don’t know if you are aware, but once you get Amarisoft’s eNB running, you can enter ‘t’ in the same terminal, and it will report link information like CQI, SNR, etc. The same for srsUE, once you have a connection between the UE and eNB, enter ‘t’ on the srsUE terminal and it will also print link information.

Thanks for this tips. I was  not aware of this.

Regards

Em

On Tue, Jan 31, 2017 at 5:14 PM, Patrick Cutno <PCutno at girdsystems.com<mailto:PCutno at girdsystems.com>> wrote:
I forgot to mention, I picked 0 dBm arbitrarily. You could instead tune the two points to -10 dBm since when you start transmitting and receiving data, the power will be higher than at idle. Too much power could hurt the signal and lead to bad performance.

From: Patrick Cutno
Sent: Tuesday, January 31, 2017 8:34 AM
To: 'Emilie Meyer' <emiliemeyer1016 at gmail.com<mailto:emiliemeyer1016 at gmail.com>>
Cc: srslte-users at lists.softwareradiosystems.com<mailto:srslte-users at lists.softwareradiosystems.com>
Subject: RE: Help with srsUE

Emilie,

Just to reduce the number of variables, try removing the duplexer and antennas from your setup. Sorry if I wasn’t clear, but you have everything right up to point B and C of your schematic. Now just connect B and C directly to the Amarisoft frontend.

  1.  Tune the power_output on Amarisoft such that the measured signal strength at point C in the schematic (or maybe A?) is 0 dBm.

     *   Correct, at point C (When point C is directly connected to the Amarisoft frontend).

  1.  Tune the TX gain in srsUE to achieve 0 dBm at point D in the schematic.

     *   Also correct

  1.  And both attenuators are set to 40 dB

     *   Yep yep.

As I mentioned before, I have run into the same issue you are having before. A COTS device works perfectly fine wirelessly, but I would get a link-failure with srsUE. When I directly connected srsUE to the Amarisoft frontend (with attenuators), I was able to get a complete connection and could run iperf tests. However I was still occasionally getting link failures. Turns out the Amarisoft’s rx gain wasn’t configured properly on my setup and Amarisoft was reporting very bad SNR’s for the uplink channel that caused the link to fail. I don’t have an explanation of why a COTS device works fine wirelessly, but the setup above helped me pinpoint my RF problem with minimal variables to consider.

I don’t know if you are aware, but once you get Amarisoft’s eNB running, you can enter ‘t’ in the same terminal, and it will report link information like CQI, SNR, etc. The same for srsUE, once you have a connection between the UE and eNB, enter ‘t’ on the srsUE terminal and it will also print link information.

Pat

From: Emilie Meyer [mailto:emiliemeyer1016 at gmail.com]
Sent: Tuesday, January 31, 2017 5:01 AM
To: Patrick Cutno <PCutno at girdsystems.com<mailto:PCutno at girdsystems.com>>
Cc: srslte-users at lists.softwareradiosystems.com<mailto:srslte-users at lists.softwareradiosystems.com>
Subject: Re: Help with srsUE

Seems like the schematic was not embedded properly in the previous mail.
The picture is attached here.

On Tue, Jan 31, 2017 at 10:57 AM, Emilie Meyer <emiliemeyer1016 at gmail.com<mailto:emiliemeyer1016 at gmail.com>> wrote:
Hi Patrick

Thanks a lot for your advice. Just to make sure that I've understood it correctly, the attached schematic shows my lab setup.

[https://mail.google.com/mail/?ui=2&ik=4af75ccfc6&view=fimg&th=159f3e3d3312a562&attid=0.1&disp=emb&realattid=ii_iylbst1e0_159f3de8197a3acf&attbid=ANGjdJ9sbscX2Kua7jO9Ap2Si2_FDVf8QL00uCf5oyqgbv4fq0pfF_5VCO631_OGC7-DLpywbocvucBsodNbGI1Jy2Ptm79oWs1rtruXHtqQTek5R57h_WksUcaHRek&sz=s0-l75&ats=1485855511453&rm=159f3e3d3312a562&zw]

What I should do:

1. Tune the power_output on Amarisoft such that the measured signal strength at point C in the schematic (or maybe A?) is 0 dBm.
2. Tune the TX gain in srsUE to achieve 0 dBm at point D in the schematic.
3. And both attenuators are set to 40 dB

Can you confirm that this is correct or not.

In my setup I have used a OAI duplexer for band 7 provided by Telmat. Did you use a similar duplexer in your setup?

Furthermore the RF frontend for Amarisoft is PCI express SDR Mimo, that came with the Amarisoft OTS100.

Best regards

Em

On Mon, Jan 30, 2017 at 2:54 PM, Patrick Cutno <PCutno at girdsystems.com<mailto:PCutno at girdsystems.com>> wrote:
Emilie,

On the srsUE side, in your config file, comment out the 'rx_gain' parameter to enable the AGC. For the 'tx_gain' parameter, I have my gain set to 82 for a transmit channel power of approximately 0 dBm.

If this is a hardware setup issue, here are the things I would try:
1: Connect using 40 dB attenuators on the rx and tx lines
2: Comment out 'rx_gain' in the srsUE config file to use AGC
3: incrementally increase the 'tx_gain' to get close to 0 dBm before the 40 dB attenuation (I don’t know about your current lab setup, but a signal analyzer of some sort would be needed to measure the dBm's).

On the Amarisoft side:
1: Incrementally increase the 'power_output' parameter to get the TX to approximately to 0 dBm before the 40 dB attenuation

Hope this helps. Also, what radio are you using for Amarisoft?

Pat

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Today's Topics:

   1. Help with srsUE (Emilie Meyer)

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Message: 1
Date: Sat, 28 Jan 2017 14:20:53 +0100
From: Emilie Meyer < >
To: srslte-users at lists.softwareradiosystems.com<mailto:srslte-users at lists.softwareradiosystems.com>
Subject: [srslte-users] Help with srsUE
Message-ID:
        <CAFF9uhqdvEo8pwg+-4B5y9Vcc5RiRDC3odtjCJr=Lh3Oc7uwEg at mail.gmail.com<mailto:Lh3Oc7uwEg at mail.gmail.com>>
Content-Type: text/plain; charset="utf-8"

Hi all

I have struggled with srsUE for weeks trying to connect it with both OAI and now Amarisoft.
In both cases, I experienced failure during Random Access procedure, I think.

I have tested with both master and next branch of srsLTE/srsUE.

What I have seen in all tests is the recurring message:

"Warning: Detected Radio-Link Failure
RRC Connection released."

How can I solve this? How can I troubleshoot what is wrong and make it work?
I really appreciate for all advices.

The output from the latest test is shown below. Also attached are the log files.

---  Software Radio Systems LTE UE  ---

Reading configuration file amarisoft.ue.conf...
Using srsLTE version 001.004.000
Opening USRP with args: type=b200
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Setting master clock rate selection to 'automatic'.
-- Asking for clock rate 16.000000 MHz...
-- Actually got clock rate 16.000000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
-- Asking for clock rate 32.000000 MHz...
-- Actually got clock rate 32.000000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass Setting frequency: DL=2680.0 Mhz, UL=2560.0 MHz Searching for cell...
Searching for cell...
Searching for cell...
Searching for cell...
Found CELL ID: 1 CP: Normal  , CFO: 3.8 KHz.
Trying to decode MIB...
 - Cell ID:         1
 - Nof ports:       2
 - CP:              Normal
 - PRB:             25
 - PHICH Length:    Normal
 - PHICH Resources: 1
 - SFN:             0
MIB received BW=5 MHz
Initializating cell configuration...
Setting Sampling frequency 5.76 MHz
Setting TX/RX offset 93 samples, 16.15 us
SIB1 received, CellID=257,  PLMN Id: MCC 001 MNC 01 Sync error.
SIB2 received
Sync error.
Random Access Transmission: seq=1, ra-rnti=0x5 Random Access Transmission: seq=2, ra-rnti=0x5 Random Access Transmission: seq=3, ra-rnti=0x5 Random Access Transmission: seq=4, ra-rnti=0x5 Random Access Transmission: seq=5, ra-rnti=0x5 Random Access Transmission: seq=6, ra-rnti=0x5 Random Access Transmission: seq=7, ra-rnti=0x5 Random Access Transmission: seq=8, ra-rnti=0x5 Random Access Transmission: seq=9, ra-rnti=0x5 Random Access Transmission: seq=10, ra-rnti=0x5
Warning: Detected Radio-Link Failure
RRC Connection released.
Sync error.
Sync error.
Sync error.
Sync error.
Sync error.
Warning: Detected Radio-Link Failure
RRC Connection released.
Sync error.
Sync error.
Sync error.
Sync error.
Sync error.
Timeout while synchronizing SFN
PCCH message received 18 bytes
Sync error.
Warning: Detected Radio-Link Failure
RRC Connection released.
PCCH message received 32 bytes
Sync error.
Sync error.
Sync error.
PCCH message received 18 bytes
Sync error.
Sync error.
Sync error.
Sync error.
Sync error.
Sync error.
PCCH message received 32 bytes
Sync error.
Timeout while synchronizing SFN
^CPCCH message received 32 bytes
Sync error.
Saving PCAP file

---  exiting  ---

--
Regards

Emilie
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Regards

Emilie

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Regards

Emilie

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Regards

Emilie

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Regards

Emilie
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