LTE

LTE Architecture Overview

Long-Term Evolution is the 4G cellular standard that replaced 3G HSPA networks. LTE is an all-IPv4Internet Protocol version 4. The fourth revision of IP using 32-bit addresses (e.g., 192.168.1.1), providing approximately 4.3 billion unique addresses. Still the most widely used internet protocol despite address exhaustion./IPv6Internet Protocol version 6. The successor to IPv4 using 128-bit addresses (e.g., 2001:0db8::1), providing a virtually unlimited address space of 3.4 x 10^38 addresses. Designed to solve IPv4 address exhaustion. packet network — unlike 3G, which carried circuit-switched voice alongside data. Voice over LTE (VoLTE) transmits calls as UDPUser Datagram Protocol. A connectionless transport protocol that sends datagrams without establishing a connection or guaranteeing delivery. Faster than TCP, it is preferred for real-time applications like DNS queries, VoIP, gaming, and streaming.-based RTP streams, the same way VoIP works over broadband.

Radio Technology Foundations

LTE uses OFDMA (Orthogonal Frequency Division Multiple Access) on the downlink and SC-FDMA on the uplink. MIMOMultiple-Input Multiple-Output. A wireless technology that uses multiple antennas at both transmitter and receiver to send and receive multiple data streams simultaneously. MU-MIMO extends this to serve multiple users concurrently. antenna configurations — typically 2x2 or 4x4 in deployed networks — multiply ThroughputThe actual rate of successful data transfer over a network, measured in bits per second. Unlike bandwidth (theoretical maximum), throughput reflects real-world performance after accounting for latency, packet loss, and protocol overhead. by transmitting independent data streams simultaneously. LTE-Advanced (LTE-A) adds carrier aggregation, bonding multiple spectrum bands to deliver peak downlink speeds of 1 Gbps.

Transition to 5G

LTE and 5GThe fifth generation of mobile network technology, offering peak speeds up to 20 Gbps, sub-millisecond latency, and massive device density. 5G uses mmWave, mid-band, and low-band spectrum for different coverage and speed trade-offs. coexist in Non-Standalone (NSA) 5G deployments: 5G NR (New Radio) handles high-speed data while the LTE core manages control-plane signaling. This allows carriers to launch 5G without immediately replacing LTE infrastructure. Standalone 5G eventually replaces LTE entirely with a cloud-native core. LatencyThe time delay for a data packet to travel from source to destination, typically measured in milliseconds (ms). Lower latency is critical for real-time applications like video calls, gaming, and financial trading. in LTE averages 30-50 ms; 5G sub-6 GHz targets 10 ms; mmWave 5G targets sub-1 ms. For networking purposes, LTE devices obtain IP addresses via carrier DHCPDynamic Host Configuration Protocol. A network protocol that automatically assigns IP addresses, subnet masks, gateways, and DNS servers to devices when they join a network. mechanisms, and NATNetwork Address Translation. A method of remapping private IP addresses to a single public IP address (and vice versa) at a router, allowing multiple devices to share one public IP. A key technique for mitigating IPv4 address exhaustion. is applied at the carrier gateway (CGNAT) when IPv4Internet Protocol version 4. The fourth revision of IP using 32-bit addresses (e.g., 192.168.1.1), providing approximately 4.3 billion unique addresses. Still the most widely used internet protocol despite address exhaustion. address exhaustion is a factor.