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
• Virtual network interface tun_srsue created upon network attach
• +100 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

srsENB has been tested and validated with the following handsets:

• LG Nexus 5
• LG Nexus 4
• Motorola Moto G4 plus
• Huawei P9/P9lite
• 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 X300
• bladeRF
• limeSDR (currently, only the PHY-layer examples, i.e., pdsch_enodeb/ue are supported)

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 libboost-thread-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.

• RF front-end driver:

  • UHD: https://github.com/EttusResearch/uhd
  • 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

The software suite can also be installed using the command sudo make install.

Execution Instructions

The srsUE, srsENB and srsEPC applications include example configuration files that should be copied and modified, if needed, to meet the system configuration. On many systems they should work out of the box.

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.

Also note that when you run the applications that all additional configuration files, for example the UE database file needed by srsEPC, reside in your current working directory. If that is not the case, you may need to specify the location of those files as command line arguments, for example using the --hss.db_file parameter in srsEPC.

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, you may just change in the source directory and start the applications as follows.

srsEPC

On machine 1, change back to the source directory and copy the srsEPC config example and UE database file.

cd ..
cp srsepc/epc.conf.example srsepc/epc.conf
cp srsepc/user_db.csv.example srsepc/user_db.csv

Now, run srsEPC with the default configuration as follows:

sudo srsepc srsepc/epc.conf

srsENB

On machine 1, but in another console, change back to the source directory and copy the main srsENB config example as well as all additional config files for RR, SIB and DRB.

cd ..
cp srsenb/enb.conf.example srsenb/enb.conf
cp srsenb/rr.conf.example srsenb/rr.conf
cp srsenb/sib.conf.example srsenb/sib.conf
cp srsenb/drb.conf.example srsenb/drb.conf

Now, run the application as follows:

sudo srsenb srsenb/enb.conf 

srsUE

On machine 2, after having following the installation instructions above, change back to the source directory and copy the srsUE example configuration:

cd ..
cp srsue/ue.conf.example srsue/ue.conf

Now run the srsUE application as follows:

sudo srsue srsue/ue.conf

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

Support

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