This is an implementation of an application programming interface (API) to connect the ns-3 network simulator to NI software defined radios (SDR) for 802.11 and LTE. Further radio access technology (RAT) interworking functionalities such as LTE-WLAN aggregation (LWA/LWIP) and dual connectivity (DC) are available.
The following figure shows an overview of the setup that can be used for 802.11 and LTE.
- Support for USRP-2974 (Link)
- Support for LabVIEW Communications System Design Suite 2.0 (LINK)
- Support for LabVIEW Communications LTE Application Framework 2.2 (LINK)
- Support for LabVIEW Communications 802.11 Application Framework 2.2 (LINK )
- Support for NI-USRP 17.2 Driver (LINK )
- Support for NI Linux RT LabVIEW Communications 2.0.1 Real-Time Target Image (LINK )
- Support for single LTE eNB or 802.11 AccessPoint (AP) and single LTE UE or 802.11 Station (Sta)
- Support for combined LTE eNB or 802.11 AccessPoint (AP) and combined LTE UE or 802.11 Station (Sta) using USRP-2974 with PCIe expansion (needed for LWA/LWIP)
- Support for two separate LTE eNB and two separate LTE UE (needed for DC)
The setup of the system can be accomplished in four steps
- Prepare the Hardware
- Install Linux RT
- Install NS-3
- Install LabVIEW Communications and Application Frameworks and run NI ns3 Application Example for 802.11 or LTE
These steps will be described in the next sections.
The following hardware setup is supported and shall be cabled as shown.
This section describes the installation of Linux RT on a USRP 2974.
The following steps need to be executed on both eNB/AP and UE/Sta USRP-2974.
To use the ns-3 simulator with the L1/L2 API and integration towards the PHY layer implementations of the LTE and 802.11 Application Framework, the proper Linux RT image for the USRP-2974 as well as for LabVIEW Communications System Design Suite 2.0 has to be used.
Download the image from LabVIEW Communications 2.0.1 Real-Time Target Image
Install the image as described under Provisioning a Real-Time Controller or USRP Stand-Alone Device for LabVIEW Communications for every USRP-2974 in the setup.
This section describes the installation of the ns-3 stack with the L1/L2 API on a USRP-2974.
The following steps need to be executed on both eNB/AP and UE/Sta USRP-2974.
Connect remotely via ssh (use ssh under Linux or putty under Windows). To find the correct IP address of the device, connect a monitor and keyboard to the USRP-2974 and run ifconfig to yield the IP address for eth0 or check under the Hardware Tab in LabVIEW Communications System Design Suite (if already available) for the registered devices. Use username root with empty password.
For an automated installation process
-
Download the script from src/ni/scripts/prepare_usrp_2974.sh,
-
Copy the script to the USRP-2974
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Execute the script on the USRP-2974
or proceed with the manual setup described below.
Install required packages from dependencies with the following commands:
opkg update
opkg install --force-downgrade packagegroup-core-buildessential git
Clone the repository and copy it to /home/root/ns-3.26
git clone https://github.com/ni/NI-ns3-ApplicationExample.git /home/root/ns-3.26
Go into ns-3 folder
cd ns-3.26
Build/compile ns-3 code:
make
The compilation should run without an error.
Install binaries related to NI examples:
make install_ni
To check whether the NI ns3 Application Example has been compiled and installed correctly, just run
For LTE:
ns3.26-ni-lte-simple-optimized
For 802.11
ns3.26-ni-wifi-simple-optimized
These calls of the compiled NI ns3 Application Examples for LTE and 802.11 are running the example in simulation mode where transmitter and receiver are both simulated in one ns3 instance without any connection to the NI Application Frameworks. Optionally the NI start script can be used to experiment with the different scenarios in simulation mode. For more information type
./ni_start.sh --help
Install LabVIEW Communications System Design Suite 2.0 and Application Frameworks 2.2 and run Application Examples
To connect with ns-3 properly over the L1/L2 API, the Application Frameworks need to be configured correctly. The instructions to setup the 802.11 Application Framework and run the NI ns3 Application Example for 802.11 can be found here: Setup 802.11 Application Framework The instructions to setup the LTE Application Framework and run the NI ns3 Application Example for LTE can be found here: Setup LTE Application Framework
In conjunction with the EU funded research project ORCA and the Open Call 1 for Extensions, an extension for the LTE/WiFi interworking technologies LWA and LWIP has been implemented. See a detailed description of the functionality from the authors HERE.
The extension can be used in simulation mode by running the following executable in the terminal:
ns3.26-ni-lte-wifi-extended-optimized
LWA/LWIP functionality can be configured in the corresponding main file: ni-lte-wifi-extended.cc. Beside simulation also the connection to the Application Frameworks using L1/L2 API is possible.
As an outcome of Open Call 2 for Extensions within the EU-funded research project ORCA, an extension of ns-3 for Dual Connectivity in LTE was developed.
The extension can be used in simulation mode as described in the following.
First, it is needed to setup the ethernet interface of your machine, e.g,, "eth0" into promiscuous mode.
This is achieved by running the following command. Please adapt the interface name to your machine settings.
sudo ip link set eth0 promisc on
Then the extension can be started by calling the appropriate binary and passing the name of the ethernet interface name:
ns3.26-dali-lte-dc-experimentation-optimized --fdDeviceName="eth0"
Further information about the usage can be found HERE .
A video tutorial, showcasing the functionality can be found HERE.
Beside simulation also the connection to the Application Frameworks using L1/L2 API is possible.
Additionally, a 5G-GFDM physical layer was integrated using an adapted version of the L1/L2 API. The implementation of the 5G-GFDM physical layer will be available under agreement with TU Dresden. Contact information can be found HERE. The ns-3 implementation is based on the LTE module with small adaptions to support configurable subcarrier spacings (SCS).
As final result of the EU-funded research project ORCA a combined main file was made available, which includes all radio access technologies and corresponding interworking working functionalities listed above. With this it is possible to run the DC extension using LTE as master and 5G-GFDM as secondary path or offload traffic over WiFi using LWA/LWIP.
The example can be used in simulation mode by running the following executable in the terminal:
ns3.26-ni-5g-lte-wifi-interworking-optimized
The functionality can be configured in the corresponding main file: ni-5g-lte-wifi-interworking.cc.
Beside simulation also the connection to the Application Frameworks using L1/L2 API is possible.
- NI examples are currently running only if binaries are build in optimized mode
- Transmission of packets with MTU size >=1500 bytes is not recommended because of packet fragmentation
- On high CPU consumption (e.g. running experiments with high data rates) the eNB stack will drop packets (CNF_TIMEOUT) to ensure further real time processing
- Single LTE UE / WiFi STAtion supported
- TapBridge support is only available for downlink and with limited stability
- LWA/LWIP
- Only downlink is supported
- Data aggregation on UE is not implemented (because NS-3 PDCP reordering is not available)
- WIFI measurement reporting over LWA/LWIP is not implemented
- LWIP implementation only works for single UE
- DC
- RLC AM is not supported
- Uplink and TCP functionalities are experimental
- System instabilities on scenarios with high throughput (>30MBits) due to emu-fd-net-device limitations and MAC PDU assembly processing
- TapBridge only available for master path (MeNB / mUE)