Tech, ExplainedNetworking, infrastructure and security
Concept

5G

From the radio to the core.

HOW IT WORKSThe phone sends aradio signal to thenearest towerThe tower's antennasaim a narrow beam atthat phone, over awide channelBackhaul carries thetraffic from the towerto the operator's coreThe 5G core checksthe SIM and placesthe traffic ina network sliceThe core handsthe traffic tothe internetWider channels, aimed beams and a core built as software give more bandwidth and less delay than 4G.HOW IT WORKSThe phonesends a radiosignal to thenearest towerThe tower'santennas aima narrow beamat thatphone, over awide channelBackhaulcarries thetraffic fromthe tower totheoperator'scoreThe 5G corechecks theSIM andplaces thetraffic in anetwork sliceThe corehands thetraffic tothe internetWider channels, aimed beams and a core built as software give more bandwidth and less delay than 4G.HOW IT WORKSThe phone sends a radio signal to thenearest tower↓The tower's antennas aim a narrow beam atthat phone, over a wide channel↓Backhaul carries the traffic from thetower to the operator's core↓The 5G core checks the SIM and places thetraffic in a network slice↓The core hands thetraffic to the internetWider channels, aimed beams and a core built as softwaregive more bandwidth and less delay than 4G.
A phone's signal reaches the tower's radio unit, which aims a beam at it, and backhaul carries the traffic to the 5G core, which checks the SIM and hands the traffic to the internet.
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5G is the fifth generation of mobile network technology, the one that Indian operators began launching in October 2022. It covers the whole path of your data: the radio signal between your phone and the tower, the links behind the tower, and the operator's core network. The rules for 5G are agreed worldwide by a standards body called 3GPP, so any 5G phone can connect to any 5G network.

Here is how it works in general. Your phone sends a radio signal to the nearest tower. The tower's radio unit and antennas are part of the radio access network, or RAN. A fibre or microwave link, called backhaul, carries the traffic from the tower to the operator's data centre. There, the packet core checks your SIM, keeps track of you as you move between towers and hands your traffic to the internet.

Three things make 5G faster than 4G. First, it uses wider radio channels. In India, most 5G runs in the 3.3–3.67 GHz band, often called the 3.5 GHz band, where one operator can use a channel of 100 MHz, several times wider than a typical 4G channel. A wider channel carries more data, which means more bandwidth. Second, the antennas have dozens of small elements. Together they aim a narrow beam at each phone, instead of sending the signal in all directions. Third, the core is software running on ordinary servers. It can split one network into separate virtual networks, each with its own speed and reliability. This is called network slicing.

Take, for example, a house with no fibre line. With fixed wireless access, a box near a window receives the 5G signal and turns it into home Wi-Fi.

Consider a port that runs its own private 5G network. Its cranes and vehicles connect to towers that only the port uses, so a crowded public network cannot slow them down.

Say you buy a new phone. Its cellular modem chip handles both 4G and 5G, and moves between them as you travel.

How is 5G different from 4G? Both carry data over radio as packets. 4G uses narrower channels and an older core that cannot do network slicing. Some early 5G networks, called non-standalone, use the 5G radio with the 4G core. Standalone 5G uses the new core as well. Open RAN is a separate idea: it lets an operator buy the tower's hardware and software from different companies.

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