RAN, 4G and 5G in plain English
What the parts of a mobile network do, and how they fit together.
The radio access network (RAN)
The RAN is everything between a phone and the operator’s core network: the antennas, the radios and the base stations that schedule who transmits, when and on which frequencies. In 4G a base station is called an eNodeB; in 5G it is a gNodeB.
Getting a RAN right is mostly about physics and timing: clean frequencies, accurate clocks (a few parts per million of error is enough to stop phones attaching), good uplink quality and sensible handover settings between neighbouring cells.
4G LTE
LTE carries everything as data over IP. The base station connects to the Evolved Packet Core, which authenticates the SIM, assigns an IP address and routes traffic to the internet or to private services. Voice runs over the same data path using IMS (VoLTE) or SIP apps.
- Bands: LTE uses many frequency bands. Band 3 (1800 MHz) is one of the most widely supported by phones.
- Mobility: phones measure neighbouring cells and the network hands them over as they move.
5G: non-standalone and standalone
5G non-standalone (NSA) adds a 5G NR radio on top of an LTE network: the phone connects to LTE first, and the 5G cell is added for extra speed (EN-DC). It is how most phones first used 5G.
5G standalone (SA) uses a 5G radio and a 5G core on their own, unlocking lower latency and features such as network slicing, but it needs phones and SIMs that support it.
- n77/n78 (3.3–4.2 GHz) are the main mid-band 5G bands in Europe.
- NR cells use flexible numerology and wider channels than LTE, which is where the extra capacity comes from.
Software-defined and open RAN
Software-defined radios and open-source stacks such as srsRAN and OpenAirInterface make it possible to build real LTE and 5G cells on general-purpose hardware. That makes them ideal for labs, private networks, training and testing new ideas, provided the radios are carefully calibrated.
Planning coverage with Sionna
Before a radio goes up, we ray-trace the site with NVIDIA Sionna to predict coverage, dead zones and data rates.
How we build
Every design we propose is tested on our own network first: radios calibrated, cells on air, phones attaching, browsing and calling. See our videos or ask for a demonstration.