srsRAN Additional Features
Multiple Simulated UEs using GNU Radio Companion
GNU Radio Companion (GRC) can be used to manipulate, and/or visualize base band I/Q data as it is sent between the UE and eNB. GRC contains ZeroMQ compatible blocks that are connected to the TCP ports used to transmit data between the UE and eNB. The Broker basically acts as a channel for information flow.
Installing GNU Radio Companion
Warning
Make sure you do not have GNU Radio already installed in your system. If so, uninstall previous versions. Also, remove other gnuradio ppas if already configured.
Installation From Binaries
To access the current released version (3.10), add the gnuradio/gnuradio-releases ppa, update the sources and install gnuradio
sudo add-apt-repository ppa:gnuradio/gnuradio-releases
sudo apt-get update
sudo apt install gnuradio
GNU Radio 3.10 will need python packaging.
sudo apt install python3-pip
pip install packaging
Tip
(Optional) If you need to increase performance, you can run volk_profile. If you encounter cannot import gnuradio error, follow the steps given here.
Connecting to an external server/internet
To allow UE to connect to the internet via the EPC, the pre-configured masquerading script srsepc_if_masq.sh must be run . The script can be found in srsRAN-e2/srsepc. The masquerading script enables IP forwarding and sets up Network Address Translation to pass traffic between the srsRAN network (through EPC) and the external network.
Note
The script must be run each time the machine is re-booted, and can be done before or while the network is running. Here we setup the network first.
Run the srsepc and srsenb. Please check the tutorial :ref:here <> for the steps.
Running the above script requires the network interface which is connected to the external network/internet to be passed as an input argument. To identify this run
route
You will see an output similar to the following:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 600 0 0 wlp2s0
10.0.2.0 0.0.0.0 255.255.255.0 U 100 0 0 enp0s3
link-local 0.0.0.0 255.255.0.0 U 1000 0 0 wlp2s0
192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp2s0
The interface (Iface) associated with the default destination is one which must be passed into the masq. script. In the above output that is the wlp2s0 (indicates wifi) interface.
The enp0s3 usually indicates ethernet interface.
Now run the Masquerading script. Plug in the interface you obtained using the command above.
sudo ./srsepc_if_masq.sh <interface>
If the script executed successfully you will get
Masquerading Interface <interface>
Warning
Make sure the UE machine is not connected to internet.
Run the srsue. On successful connection (RRC connected) A virtual network interface named tun_srsue will be created on the UE machine and it will be assigned an IP address by the EPC with format 172.16.0.x.
Here we assume that the UE is assigned an IP address 172.16.0.2
Check if you can ping the EPC (SGi IP address: 172.16.0.1)
ping 172.16.0.1
Once this is successful, we will configure the EPC to act as a gateway to the external network/internet for the UE. On the UE machine run
sudo route add default gw 172.16.0.1 tun_srsue
That’s it. Test by pinging Google’s DNS server
ping 8.8.8.8
Connecting USRPs to VirtualBox VMs
Connecting B210/B-205 mini over USB 3.0
Connecting X310/N310 through ethernet
Tip
If your machine, does not support 10G Ethernet then you can use adapters (USB-C/USB3.0 to 10G ethernet adapters)
TODO
Add images here. USRP IP address will change depending on the FPGA Image that it loaded. Indicate this in the instructions below.
Make sure the USRP is connected to the machine’s secondary NIC (Ethernet in this case) and the VM is not running. In VirtualBox’s Settings window, click the Network tab, and then Adpater 2. Leave Adapter 1 alone so that you still have Internet access inside the VM. In Attached to, choose Bridged Adapter so that the VM has direct access to the physical network adapter. Then in Name, choose the secondary NIC (ethernet) that is physically connected to the USRP.
Save the configuration and boot into the Virtual Machine.
Make sure the network adapter is visible.
ifconfig -a
sudo ifconfig enp0s8 192.168.10.1
sudo ip route add 192.168.10.0/24 dev enp0s8
ip route
sudo ifconfig enp0s8 up
ping 192.168.10.2
uhd_find_devices
Now you should be able to ping the USRP from the VM