Basic OAI Tutorial

Objective

This objective of this tutorial is to establish a LTE connection between the SDR based UE and eNB.

Quickstart Option

We have a pair of images available. It has all the necessary driver and software pre-installed, and two scripts available to immediately boot up the eNB and UE. This quickstart assumes use of Sandbox1, nodes 1-1, and 1-2. The image was built following the tutorial available at: ​OAI Gitlab tutorial, no S1 interface

If you intend to use graphical user interface please make sure to install appropriate tools on your local machine and configure X11 forwarding.

Remote Graphical Access

We really don't want to encourage this too much since it depends on network performance especialy on slow links. In ORBIT, remote graphical access is a two step process: tunneling from your local machine to the console of the domain you are working on that is followed by tunneling from the console to the node. Assumption is that one is using Linux baseline images and thus ​X Window System (X11) based graphical environment.

Remote X11 Access For Linux

Simply use the -X or -Y flags, e.g. for remote graphical access to node1-1.sb1.orbit-lab.org:

ssh -Y -t sb1.orbit-lab.org ssh -Y -t root@node1-1

If you get an error about ssh keys not matching, you MUST follow the instructions for configuring your ssh keys; you will not b able to do X11 forwarding until this problem is fixed.

Remote X11 Access For Windows

In addition to ssh client, remote X11 access on Windows requires installation of X11 Server. Number of open source or free servers is available including:

1. ​VcXsrv
2. ​Xming
3. ​mobaXterm (includes ssh client)

to name a few.

As an illustration, we will use configuration based on Putty and VcXsrv and connect with remote graphics capability to the node1-1.sb1:

• Install Putty and make sure you can log into ORBIT gateway or console
• Install VcXsrv and make sure it is running say on display 1 (without any applications)
• Start Putty and load the appropriate session
• Configure X11 forwarding under "Connection→SSH→X11":
  • Check mark on "Enable X11 forwarding"
  • Set "X display location" to: 127.0.0.1:1 (note matching display number)
• Save the session
• Open the session to SB1 i.e. connect to the console.sb1.orbit-lab.org
• On the console execute

    ssX -Y -t root@node1-1
  

and connect to the node.

Remote X11 Access For MAC

1. Mac: You must use an X11 capable ssh client such as FIXME, or install a standalone X11 client such as FIXME
   1. Start x11 capable client
   2. SSH to console
   3. SSH to node

Prepare the nodes

1. Load the two images with the OAI code to nodes 1-1 and 1-2. This enables running the experiment with no compilation needed.
   1. Load the eNB image to node1-1.
      1. omf load -t node1-1 -i mf-oai-enb.ndz
   2. Load the UE image to node1-2.
      1. omf load -t node1-2 -i mf-oai-ue.ndz
2. Turn the nodes on.
   1. omf tell -a on -t node1-1,node1-2
3. Open a terminal to each node. You must enable X11 Forwarding to see the GUI and statistics screens.
   1. You will need at lease one terminal per node, for the statistics screens. Even more if you want to run additional commands. For details, refer to the Remote Graphical Access section.

Execute the experiment

1. On node1-1, execute script ./run_enb.sh
   1. Wait for the visualization to appear.
2. On node1-2, execute script ./run_ue.sh
   1. Wait for the visualization to appear.
3. These scripts will create interface oai0 and assign an address.
   1. Use ifconfig or ip a to see the address assigned.
   2. By default the eNB has address 10.0.1.1, and the UE has address 10.0.1.9, but you should double check.
4. You should be able to ping from one node to the other on these addresses.
   1. From UE, ping 10.0.1.1 or to see live statistics mtr 10.0.1.1
   2. As you send traffic, you should see the visualization change, showing a larger constellation as below.