project release , developing an open stack for deploying LTE/4G cellular network components without specialized equipment, using only universal programmable transceivers, with signal form and modulation defined programmatically (SDR, Software Defined Radio). Project code is licensed under AGPLv3.
SrsLTE implementation of LTE UE (User Equipment, client components for connecting subscribers to the LTE network), LTE base station (eNodeB, E-UTRAN Node B), as well as elements of the LTE core network (MME — Mobility Management Entity for interaction with base stations, HSS — Home Subscriber Server for storing subscriber database and information about services tied to subscribers, SGW — Serving Gateway for processing and routing packets for base stations, PGW — Packet Data Network Gateway for connecting subscribers to external networks.
In the new version:
- The library implementing the physical layer of the stack has been redesigned ();
- Support for the TDD format (Time Division Duplex) has been added to srsUE (LTE UE, User Equipment, components on the user side necessary for subscriber connection to the LTE network), in addition to the previously supported and more widespread frequency allocation format in FDD (Frequency Division Duplex); (Time Division Duplex) in addition to the previously supported and more widely used frequency distribution format in the FDD (Frequency Division Duplex) channel;
- Support for Carrier Aggregation has been added to srsUE to increase bandwidth to the end user;) to increase the bandwidth to the end user;
- Support for paging messages, which are commonly used to establish a direct communication channel between the subscriber and the base station, has been added to srsENB (implementation of the base station) and srsEPC (core network components); , typically used to configure a direct communication channel between the subscriber and the base station;
- Support for user-plane encryption has been added to srsENB. Support for NAS-plane encryption was implemented earlier;
- A channel simulator for 3GPP channels EPA, EVA, and ETU has been implemented;
- A virtual RF driver based on ZeroMQ has been implemented to provide I/Q signal transmission over IPC/network.
Main Features:
- The system can work with any programmable transceivers supported by drivers Ettus UHD (Universal Hardware Driver) and bladeRF, capable of operating with a bandwidth of 30.72 MHz. The operation of srsLTE has been tested with USRP B210, USRP B205mini, USRP X300, limeSDR, and bladeRF boards;
- High-speed optimized decoder using Intel SSE4.1/AVX2 instructions to achieve performance over 100 Mbps on standard hardware. The standard implementation of the decoder in C language provides performance at the level of 25 Mbps;
- Full compatibility with LTE standard version 8 and partial support for some features from version 9;
- Configuration available for operation in Frequency Division Duplex (FDD) mode;
- Tested bandwidths: 1.4, 3, 5, 10, 15, and 20 MHz;
- Support for transmission modes 1 (single antenna), 2 (transmit diversity), 3 (closed-loop spatial multiplexing), and 4 (closed-loop spatial multiplexing);
- Equalizer supporting ZF and MMSE frequency coding;
- Support for creating services for delivering multimedia content in broadcast and multicast modes;
- Ability to maintain detailed logs linked to levels and debugging dumps;
- Packet capture system at the MAC layer, compatible with the network analyzer Wireshark;
- Availability of metrics with tracing data in command line mode;
- Detailed configuration files;
- Implementation of LTE MAC, RLC, PDCP, RRC, NAS, S1AP, and GW levels.
Source: opennet.ru
