srsLTE

srsLTE is a free and open-source LTE software suite developed by SRS (www.softwareradiosystems.com).

It includes:

• srsUE - a complete SDR LTE UE application featuring all layers from PHY to IP
• srsENB - a complete SDR LTE eNodeB application
• srsEPC - a light-weight LTE core network implementation with MME, HSS and S/P-GW
• a highly modular set of common libraries for PHY, MAC, RLC, PDCP, RRC, NAS, S1AP and GW layers.

srsLTE is released under the AGPLv3 license and uses software from the OpenLTE project (http://sourceforge.net/projects/openlte) for some security functions and for RRC/NAS message parsing.

Common Features

• LTE Release 8 compliant (with selected features of Release 9)
• FDD configuration
• Tested bandwidths: 1.4, 3, 5, 10, 15 and 20 MHz
• Transmission mode 1 (single antenna), 2 (transmit diversity), 3 (CCD) and 4 (closed-loop spatial multiplexing)
• Frequency-based ZF and MMSE equalizer
• Evolved multimedia broadcast and multicast service (eMBMS)
• Highly optimized Turbo Decoder available in Intel SSE4.1/AVX2 (+100 Mbps) and standard C (+25 Mbps)
• MAC, RLC, PDCP, RRC, NAS, S1AP and GW layers
• Detailed log system with per-layer log levels and hex dumps
• MAC layer wireshark packet capture
• Command-line trace metrics
• Detailed input configuration files

srsUE Features

• Cell search and synchronization procedure for the UE
• Soft USIM supporting Milenage and XOR authentication
• Hard USIM support using PCSC framework
• Virtual network interface tun_srsue created upon network attach
• 150 Mbps DL in 20 MHz MIMO TM3/TM4 configuration in i7 Quad-Core CPU.
• 75 Mbps DL in 20 MHz SISO configuration in i7 Quad-Core CPU.
• 36 Mbps DL in 10 MHz SISO configuration in i5 Dual-Core CPU.

srsUE has been fully tested and validated with the following network equipment:

• Amarisoft LTE100 eNodeB and EPC
• Nokia FlexiRadio family FSMF system module with 1800MHz FHED radio module and TravelHawk EPC simulator
• Huawei DBS3900
• Octasic Flexicell LTE-FDD NIB

srsENB Features

• Round Robin MAC scheduler with FAPI-like C++ API
• SR support
• Periodic and Aperiodic CQI feedback support
• Standard S1AP and GTP-U interfaces to the Core Network
• 150 Mbps DL in 20 MHz MIMO TM3/TM4 with commercial UEs
• 75 Mbps DL in SISO configuration with commercial UEs
• 50 Mbps UL in 20 MHz with commercial UEs

srsENB has been tested and validated with the following handsets:

• LG Nexus 5 and 4
• Motorola Moto G4 plus and G5
• Huawei P9/P9lite, P10/P10lite, P20/P20lite
• Huawei dongles: E3276 and E398

srsEPC Features

• Single binary, light-weight LTE EPC implementation with:
  • MME (Mobility Management Entity) with standard S1AP and GTP-U interface to eNB
  • S/P-GW with standard SGi exposed as virtual network interface (TUN device)
  • HSS (Home Subscriber Server) with configurable user database in CSV format

Hardware

The library currently supports the Ettus Universal Hardware Driver (UHD) and the bladeRF driver. Thus, any hardware supported by UHD or bladeRF can be used. There is no sampling rate conversion, therefore the hardware should support 30.72 MHz clock in order to work correctly with LTE sampling frequencies and decode signals from live LTE base stations.

We have tested the following hardware:

• USRP B210
• USRP B205mini
• USRP X300
• limeSDR
• bladeRF

Build Instructions

• Mandatory requirements:
  • Common:
    • cmake https://cmake.org/
    • libfftw http://www.fftw.org/
    • PolarSSL/mbedTLS https://tls.mbed.org
  • srsUE:
    • Boost: http://www.boost.org
  • srsENB:
    • Boost: http://www.boost.org
    • lksctp: http://lksctp.sourceforge.net/
    • config: http://www.hyperrealm.com/libconfig/
  • srsEPC:
    • Boost: http://www.boost.org
    • lksctp: http://lksctp.sourceforge.net/
    • config: http://www.hyperrealm.com/libconfig/

For example, on Ubuntu 17.04, one can install the required libraries with:

sudo apt-get install cmake libfftw3-dev libmbedtls-dev libboost-program-options-dev libconfig++-dev libsctp-dev

Note that depending on your flavor and version of Linux, the actual package names may be different.

• Optional requirements:

  • srsgui: https://github.com/srslte/srsgui - for real-time plotting.
  • libpcsclite-dev: https://pcsclite.apdu.fr/ - for accessing smart card readers

• RF front-end driver:

  • UHD: https://github.com/EttusResearch/uhd
  • SoapySDR: https://github.com/pothosware/SoapySDR
  • BladeRF: https://github.com/Nuand/bladeRF

Download and build srsLTE:

git clone https://github.com/srsLTE/srsLTE.git
cd srsLTE
mkdir build
cd build
cmake ../
make
make test

Install srsLTE:

sudo make install
sudo srslte_install_configs.sh

This installs srsLTE and also copies the default srsLTE config files to the user's home directory (~/.srs).

Execution Instructions

The srsUE, srsENB and srsEPC applications include example configuration files that should be copied (manually or by using the convenience script) and modified, if needed, to meet the system configuration. On many systems they should work out of the box.

By default, all applications will search for config files in the user's home directory (~/.srs) upon startup.

Note that you have to execute the applications with root privileges to enable real-time thread priorities and to permit creation of virtual network interfaces.

srsENB and srsEPC can run on the same machine as a network-in-the-box configuration. srsUE needs to run on a separate machine.

If you have installed the software suite using sudo make install and have installed the example config files using sudo srslte_install_configs.sh, you may just start all applications with their default parameters.

srsEPC

On machine 1, run srsEPC as follows:

sudo srsepc epc.conf

Using the default configuration, this creates a virtual network interface named "srs_spgw_sgi" on machine 1 with IP 172.16.0.1. All connected UEs will be assigned an IP in this network.

srsENB

Also on machine 1, but in another console, run srsENB as follows:

sudo srsenb enb.conf
./srsepc_if_masq.sh <interface connected to internet>

srsUE

On machine 2, run srsUE as follows:

sudo srsue

Using the default configuration, this creates a virtual network interface named "tun_srsue" on machine 2 with an IP in the network 172.16.0.x. Assuming the UE has been assigned IP 172.16.0.2, you may now exchange IP traffic with machine 1 over the LTE link. For example, run a ping to the default SGi IP address:

ping 172.16.0.1

Pinging google DNS

Once the virtual network interface is up and you can ping the eNB, run the following command:

sudo route add default gw 172.16.0.1 tun_srsue

and then test the ip-traffic by pinging the servers:

ping 8.8.8.8

Browsing internet throught tun_srsue

• Install the resolvconf package

sudo apt install resolvconf

Edit /etc/resolvconf/resolv.conf.d/head and add the following:

# Make edits to /etc/resolvconf/resolv.conf.d/head
nameserver 8.8.4.4 
nameserver 8.8.8.8

Restart the resolvconf service.

sudo service resolvconf restart

Using srsLTE in simulation mode

• Follow the link srsLTE-ZeroMQ to install the required libraries.

• Network Namespace Creation

sudo ip netns add ue1

• Running the EPC

sudo srsepc epc.conf

• Running the eNodeB

sudo srsenb --rf.device_name=zmq --rf.device_args="fail_on_disconnect=true,tx_port=tcp://*:2000,rx_port=tcp://localhost:2001,id=enb,base_srate=23.04e6" enb.conf

• Running the UE

sudo srsue --rf.device_name=zmq --rf.device_args="tx_port=tcp://*:2001,rx_port=tcp://localhost:2000,id=ue,base_srate=23.04e6" --gw.netns=ue1 ue.conf

Support

Mailing list: http://www.softwareradiosystems.com/mailman/listinfo/srslte-users