[srslte-users] [Commercial UE] Impossible to see the created LTE network

Fri Jun 29 09:13:26 UTC 2018

Hi Vincent,

i have a few suggestions/ideas/comments:

  *   For me srsENB works relatively fine without an GPSDO, but you can never be sure especially different UEs might behave differently
  *   To set a frequency use only dl_earfcn parameter and don't set dl_freq and ul_freq, because this caused some problems for my commercial UE (there was also something missing in the source code for it to work properly but I will have to look what exactly was wrong)
  *   You set the bandwidth with n_prb, for me 25 (5MHz) worked best for testing because lower values sometimes resulted in wierd behaviour and higher is more demanding for your PC
  *   I suggest to set authentification algo to milenage
  *   If you work in a Faraday Cage I would check at first inside if you phone will find any commercial networks (it should not). Then set your MCC and MNC in eNB and EPC to a commercial network according to https://en.wikipedia.org/wiki/Mobile_country_code -> e.g. if you are in Switzerland set MCC to 228 and MNC to 01 and now your phone should "see" a Swisscom 4G Network. Be sure only to use this in a Faraday Cage as you are not allowed to use these MCC/MNC combination, but so you can try if it's just the phone which doesn't show Test Networks like 00101

Richard Stenzel

________________________________
From: srslte-users <srslte-users-bounces at lists.softwareradiosystems.com> on behalf of Falconieri Vincent <vincentf at student.ethz.ch>
Sent: Wednesday, June 27, 2018 4:05 PM
To: srslte-users at lists.softwareradiosystems.com
Subject: [srslte-users] [Commercial UE] Impossible to see the created LTE network

Dear srsLTE community,

Since about one week, I'm trying to have a working setup (ENC + ENB + Commercial UE) : I want the UE to be able to connect to the ENB.
Unfortunately, I can't get it working, even with reading most of the old SRSLTE_list e-mails, documentation provided and information found online.
Sorry for the big e-mail, I tried to solved it by myself in vain, and tried to compile all available information once, here.

## Setups
I tried 2 setups, both on the same machine (Laptop ASUS FX550V, i5-6300HQ 3.2 Ghz + 8Gb RAM)
1. Arch-linux (performance mode for CPU, packets up to date) :
    + srsENC (compiled manually)
    + srsENB (compiled manually)
    + UHD (compiled manually and also from AUR repository. Right now :  UHD_3.11.1.0-0-unknown)
    + USRP B210 (default firmware downloaded via the python script provided, connected on USB 3.0)
    + 2 VERT900 antennas (connected on A:RX2 and A:RX/TX, 824 to 960 MHz, 1710 to 1990 MHz from documentation)
    + Samsung Galaxy S6 Edge+ (SM-G928F, not rooted)
2. Ubuntu 17.04 (performance mode for CPU, packets up to date, installed on a USB Key 3.0) :
    + srsENC (compiled manually)
    + srsENB (compiled manually)
    + UHD (from repo (v3.10 I guess) and also compiled manually with version UHD 3.12.0.HEAD-0-gec786351)
    + USRP B210 (default firmware downloaded via uhd_images_downloader, connected on USB 3.0)
    + 2 VERT900 antennas (connected on A:RX2 and A:RX/TX, 824 to 960 MHz, 1710 to 1990 MHz from documentation)
    + Samsung Galaxy S6 Edge+ (SM-G928F, not rooted)

## Problems
I can't see the created LTE network by the setup from the smartphone (Parameters > Mobile networks > Network operators > Networks lookup) even if the setup seems to work.
I also tried to get more precise information with the help of apps like "Network Signal Guru", "G-NetTrack Lite", "Cell Signal Monitor" but without a rooted phone, it displays only information on the connected cell. (As I can't even detect mine, I can't get any information from these apps).
The smartphone can see commercial network without problem. (At least 3 commercial networks listed outside Faraday cage)

## Work
srsENC : runs flawlessly. No errors in logs.

srsENB : connects correctly to srsENC.
* On setup 1. (=Arch) : A lot of UOSDL (even in performance mode),
The last errors I get, which I never resoled is :
    [ERROR] [STREAMER] recv packet demuxer unexpected sid 0x190038
    [ERROR] [STREAMER] recv packet demuxer unexpected sid 0xfffe000e

* On setup 2. (=Ubuntu) : nearly no UOSDL. Still some entry in enb.log :
    12:57:55.434535 [RF  ] [W] Overflow
No other errors displayed. No tentative of connection from UE in the logs.

* On both setups : Tried with out-of-the-box conf files, tried to increase gain (Tx 86, Rx 60), tried other earfcn (1800, 1949, 1600, ...), recompile srsENB with and without srsGUI, run with different version/source of uhd ...  without improvement.
Enable pregenerate_signals allowed to get less UOSDL. Add some devices_args ("recv_frame_size=1024", ...) allowed to get new errors message, but not a working setup.

UHD Driver : "make test" only provides 1 error. "./tests_messages" outputs some errors :
    (In faraday cage with sudo)
    Test Burst ACK    ->     9 successes,   2 failures
    Test Underflow    ->     7 successes,   5 failures
    Test Time Error   ->     4 successes,   7 failures
    Test Late Command   ->    16 successes,   0 failures
"./benchmark_rate --tx_rate 6.25e6 --rx_rate 6.25e6 --duration 30" gives no error on USB 3.0.
Correctly detects the B210.
Can receive data from the USRP (./rx_ascii_art_dft --rate 1000000 --freq 1700 --rx-gain 60 gives a "moving graph")

USRP B210 Card : LEDs work correctly (blink of the LED in case of UOSDL), used by someone else, it worked for another project but not on these frequencies and not for this usage.

Laptop : working for diverse other usages. Never used it for "real time hardware" applications (so USB 3.0 ports never tested in equivalent settings)
Smartphone : working for daily usage. Roaming is working. 4G LTE verified. More details on frequencies this UE can handle : https://www.frequencycheck.com/models/vDm7R/samsung-sm-g928f-galaxy-s6-edge-lte-a-64gb-samsung-zen

## Aside notes
* All tests are conducted in a Faraday cage.
* I may have access to another smartphone (that I can root) and might get another computer by the end of the week for further testing.
* I have no GPSDO on the B210. It seems that some people (even in this list) managed to make it work without this. Am I making a mistake ? Is it mandatory ?
* Monitoring the CPU gives 30% charge when EPC/ENB running, 10% without. Numerous L(ate),D(rop),O(verflow),U(ndeflow) in powersaving mode, nearly none in performance mode (but still some. 0 to 2 per minute in the best run I ever had).
* USB 2.0 on the same machine provides a lot of UOSDL without improvement.
* I have a configurable sim card (sysmocom) that I keep for later steps. Not used now.
* Antennas are placed orthogonally from each other.
* With the notes I took, and what I tested, I think I have enough to start a wiki .. we could talk about it when my problem will be solved, if you are interested. :)

## Questions
* Some gave the advice to reduce the bandwidth to 5 Mhz to prevent timing issues. Do we agree we can't control this parameter directly, but only through the number of ressource block ? (tried n_prb with almost all values displayed in the conf.example : 6,15,50, ...)
* Do you know if mcc/mnc/tac/... should have a particular value to work with the commercial UE ? As far as I understand, it should be fine with default values, isn't it ? It should behave like roaming.
* Do you have an idea of what can get wrong ?

## Useful informations :
Some captures and complementary informations are joined to this e-mail. Feel free to ask anything I can try that could be relevant.
    - Error with cache : with "pregenerate_signals" there is less UDLO, but still.
    - Error_No_network_visible (2) : One run (as all the other, but this one has nothing else "special") where the smartphone can't see the network
    - Error_Recv_packet_demuxer (2) : Runs where a major error occured. It seems that unpluging and repluging the card (so the firmware is copied again) solve the issue. Seems it happens when there is 2 runs in a row, with different enb.conf.
I unfortunately did not manage to get a "nice and smooth" run today. I don't know why. If I managed to get one, I'll give you the logs.

Thanks for your time,
Hope we'll be able to find a solution or at least ideas to explore
Best regards,
F. Vincent

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