Chapter 8 - Trouble shooting

  • Issue : UHD missing (ENB with USRP B210) Copy and paste these commands into your terminal. This will install UHD software as well as allow you to receive package updates

    sudo bash -c 'echo "deb http://files.ettus.com/binaries/uhd_stable/repo/uhd/ubuntu/`lsb_release -cs` `lsb_release -cs` main" > /etc/apt/sources.list.d/ettus.list'
sudo apt-get update
sudo apt-get install -t `lsb_release -cs` uhd

    reference : http://ananmxw.blog.163.com/blog/static/2111441192013732399686/

  • issue : "Error 111" while trying to reconnect to the network

    The quick fix is to compare MAC values only when EPC's own MAC is not 0. You may change Line 317 in openair-cn/NAS/COMMON/API/NETWORK/nas_message.c
from 
if (mac != header->message_authentication_code) {
to
if ((mac != 0) && (mac != header->message_authentication_code)) {

  • RX/TX overflow or busy

  • make sure that you have at least 4 CPU cores running at least at 2.7GHz without the freq scaling (watch grep \"cpu MHz\" /proc/cpuinfo), see https://twiki.eurecom.fr/twiki/bin/view/OpenAirInterface/OpenAirKernelMainSetup
  • make sure that you are running 64-bit lowlatency kernel, uname -a
  • rebuild the lte-softmodem, ./build_oai --eNB -C, optionally add -I to check the packages
  • use sudo with option -E
  • use chrt to change the process priority, i.e. sudo -E chrt 99 -E ./lte-softmodem ...