srsLTE

srsLTE is a free and open-source LTE software suite developed by SRS (www.softwareradiosystems.com). See the srsLTE project pages (www.srslte.com) for documentation, guides and project news.

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 NAS message parsing.

Common Features

• LTE Release 10 aligned
• 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)
• Carrier Aggregation support
• QAM256 support in Downlink
• Frequency-based ZF and MMSE equalizer
• Evolved multimedia broadcast and multicast service (eMBMS)
• Highly optimized Turbo Decoder available in Intel SSE4.1/AVX2 (+150 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
• Channel simulator for EPA, EVA, and ETU 3GPP channels
• ZeroMQ-based fake RF driver for I/Q over IPC/network

srsUE Features

• FDD and TDD configuration
• 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
• QoS support
• 150 Mbps DL in 20 MHz MIMO TM3/TM4 or 2xCA configuration (195 Mbps with QAM256)
• 75 Mbps DL in 20 MHz SISO configuration (98 Mbps with QAM256)
• 36 Mbps DL in 10 MHz SISO configuration

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

• FDD configuration
• 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 (195 Mbps with QAM256)
• 75 Mbps DL in SISO configuration with commercial UEs
• 50 Mbps UL in 20 MHz with commercial UEs
• User-plane encryption

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
• Support for paging

Hardware

srsLTE has native support for the Ettus Universal Hardware Driver (UHD) and the bladeRF driver. We also support SoapySDR. Thus, any hardware supported by SoapySDR 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 B2x0
• USRP B205mini
• USRP X3x0
• LimeSDR
• bladeRF

For Ettus Research equipment we recommended the LTS version of UHD, i.e. either 3.9.7 or 3.15.

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, one can install the mandatory build dependencies with:

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

or on Fedora:

dnf install cmake fftw3-devel mbedtls-devel lksctp-tools-devel libconfig-devel boost-devel

For CentOS, use the Fedora packages but replace libconfig-devel with just libconfig.

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
  • ZeroMQ: https://github.com/zeromq

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
srslte_install_configs.sh user

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

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 (~/.config/srslte) 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 srslte_install_configs.sh user, you may just start all applications with their default parameters.

srsEPC

On machine 1, run srsEPC as follows:

sudo srsepc

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

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

Support

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