srsRAN 4G 23.11 has been released — an open-source implementation of the 4G/LTE stack.

The software radio systems Radio Access Network project, or srsRAN, aims to implement 4G/LTE and 5G stacks. Previously, the project was known as srsLTE.

Key changes compared to the previous version:

• Fixed srsUE issues related to 5, 10, 15, and 20 MHz bandwidths.
• A new algorithm for frequency calculation has been added.
• CMake has been updated.
• Various bug fixes that enhance stability and performance.

Key modules of srsRAN 4G:

• srsENB (software radio systems eNodeB) — implementation of Evolved UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network NodeB or E-UTRAN NodeB, or simply eNodeB (eNB). Essentially, this is a software implementation of a 4G/LTE base station;
• srsUE (software radio systems User Equipment) — implementation of a 4G/LTE modem that can connect to the eNB base station;
• srsEPC — implementation of the core network, which includes MME (Mobility Management Entity), HSS (Home Subscriber Server), SGW (Serving Gateway), and PGW (PDN (Packet Data Network) Gateway).

Main Features:

• implementation of both a base station and a software modem;
• support for both software and hardware SIM cards (via PC/SC) for srsUE;
• support for bandwidths of 1.4, 3, 5, 10, 15, and 20 MHz;
• support for AES;
• optimization for SSE4.1/AVX2;
• support for LTE Release 10;
• support for Intra-ENB and Inter-ENB for eNodeB.

It's worth noting that srsRAN also develops and supports O-RAN 5G..

Key limitations

• No support for VoLTE. (VoLTE operations can be implemented using a third-party IMS, such as Kamailio, available at kamailio.org, using the article https://open5gs.org/open5gs/docs/tutorial/02-VoLTE-setup and here’s how VoLTE works. https://www.youtube.com/watch?v=gBX-ZX_d1uY)
• For 5G, only support for gNodeB (next generation NodeB) as both CU and DU/RU is implemented — that is, the base station, but the software modem is not implemented.
• Only FR1 is supported.
• No support for 2G and 3G.

Unlike Osmocom CNI, srsRAN aims to create a 4G and 5G stack for IP traffic transmission. At the same time, Osmocom CNI focuses on implementing 2G and 3G, which are oriented towards SMS, USSD, and voice transmission. That’s why Osmocom CNI can transmit voice traffic not only to IP-PBX (IP-ATS) type Asterisk but also, for instance, to E1 using icE1usb..

Source: linux.org.ru