What is Latency?
In 5G networks, latency is the time delay for a data packet to travel from source to destination (one-way) or make a round trip (RTT). It is one of the most critical performance KPIs, differentiating 5G from previous generations. 5G NR targets 4 ms user-plane latency for eMBB and as low as 1 ms for uRLLC — compared to 30–50 ms typical in 4G LTE.
How Does Latency Work?
Latency in mobile networks has multiple components: Radio TTI (1 ms for LTE, 0.125 ms mini-slot for 5G uRLLC), HARQ retransmission delay, scheduling delay, transport network delay, and core network processing. 5G reduces latency through: mini-slots (0.125 ms transmission intervals), early HARQ feedback, configured grants (no scheduling request), MEC edge computing (moves UPF to the antenna site), and network slicing with reserved resources.
Use Cases
uRLLC: remote surgery (<1 ms), factory robot control, autonomous driving. eMBB: cloud gaming (targeting <20 ms), interactive AR/VR. Comparison: 5G uRLLC (1 ms), 5G eMBB (4 ms), 4G LTE (30 ms), 3G UMTS (100 ms).
3GPP / Standards Reference
3GPP TR 38.913 (5G Requirements Study), TS 22.261 (Service Requirements for the 5G System)
Related Terms
uRLLC | MEC | CUPS | Network Slicing | TTI
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
