LTE

LTE, or Long-Term Evolution, is a standard for wireless broadband communication designed for mobile devices and data terminals. Developed by the 3GPP, it represents a major step beyond 3G technologies and serves as the foundation for contemporary 4G networks, with ongoing enhancements to support higher data rates, lower latency, and better efficiency. The first LTE release (Release 8) appeared around 2008–2009.

Technically, LTE uses the Evolved UTRAN (E-UTRA) radio interface. The downlink employs OFDMA, while the uplink uses SC-FDMA, which helps reduce peak-to-average power ratios on user devices. Key features include multiple-input multiple-output (MIMO) antenna systems, carrier aggregation to combine several frequency blocks for higher throughput, and flexible channel bandwidths from 1.4 to 20 MHz (and wider in some deployments). The core network is the Evolved Packet Core (EPC), a flat, all-IP architecture that simplifies mobility and data transport and supports QoS for IP traffic.

Performance and evolution: LTE introduced substantial data-rate improvements over 3G. The base specification offered theoretical downlink speeds around 100 Mbps and uplink around 50 Mbps. LTE-Advanced (Release 10) and beyond added features such as wider carrier bandwidths and higher-order MIMO, pushing theoretical downlink speeds toward or beyond 1 Gbps in optimal conditions, with real-world speeds typically ranging in the tens to hundreds of Mbps. LTE-Advanced Pro, sometimes called 4.5G, further extends capabilities.

Voice services on LTE commonly use VoLTE (Voice over LTE) via IMS, replacing traditional circuit-switched voice in many networks; legacy fallback methods remain in some situations. LTE remains widely deployed and forms the payload of many current mobile broadband networks, while progressively integrating with 5G deployments.