LTE technology

What is LTE?

 In telecommunications, Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements.LTE, sometimes known as 4G LTE, is a type of 4G technology. Short for "Long Term Evolution", it's slower than "true" 4G, but significantly faster than 3G, which originally had data rates measured in kilobits per second, rather than megabits per second.

LTE Bandwidth:

LTE supports deployment on different frequency bandwidths. The current specification outlines the following bandwidth blocks: 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz, and 20MHz. Frequency bandwidth blocks are essentially the amount of space a network operator dedicates to a network. Depending on the type of LTE being deployed, these bandwidths have slightly different meaning in terms of capacity.. An operator may choose to deploy LTE in a smaller bandwidth and grow it to a larger one as it transitions subscribers off of its legacy networks (GSM, CDMA, etc.).

How LTE works:

LTE uses two different types of air interfaces (radio links), one for downlink (from tower to device), and one for uplink (from device to tower). By using different types of interfaces for the downlink and uplink, LTE utilizes the optimal way to do wireless connections both ways, which makes a better optimized network and better battery life on LTE devices. For the downlink, LTE uses an OFDMA (orthogonal frequency division multiple access) air interface as opposed to the CDMA (code division multiple access) and TDMA (time division multiple access) air interfaces we’ve been using since 1990. What does this mean? OFDMA (unlike CDMA and TDMA) mandates that MIMO (multiple in, multiple out) is used. Having MIMO means that devices have multiple connections to a single cell, which increases the stability of the connection and reduces latency tremendously. It also increases the total throughput of a connection. We’re already seeing the real-world benefits of MIMO on WiFi N routers and network adapters. MIMO is what lets 802.11n WiFi reach speeds of up to 600Mbps, though most advertise up to 300-400Mbps. There is a significant disadvantage though. MIMO works better the further apart the individual carrier antennae are. On smaller phones, the noise caused by the antennae being so close to each other will cause LTE performance to drop. WiMAX also mandates the usage of MIMO since it uses OFDMA as well. HSPA+, which uses W-CDMA (a reworked, improved wideband version of CDMA) for its air interface, can optionally use MIMO, too. For the uplink (from device to tower), LTE uses the DFTS-OFDMA (discrete Fourier transform spread orthogonal frequency division multiple access) scheme of generating a SC-FDMA (single carrier frequency division multiple access) signal. As opposed to regular OFDMA, SC-FDMA is better for uplink because it has a better peak-to-average power ratio over OFDMA for uplink. LTE-enabled devices, in order to conserve battery life, typically don’t have a strong and powerful signal going back to the tower, so a lot of the benefits of normal OFDMA would be lost with a weak signal. Despite the name, SC-FDMA is still a MIMO system. LTE uses a SC-FDMA 1×2 configuration, which means that for every one antenna on the transmitting device, there’s two antennae on the base station for receiving.

LTE Network Architecture: 

The high-level network architecture of LTE is comprised of following three main components:

• The User Equipment (UE).

• The Evolved UMTS Terrestrial Radio Access Network (E-UTRAN).

• The Evolved Packet Core (EPC).

Future of LTE Technology: With 5G generating so much buzz, it is easy to overlook the groundbreaking services being enabled by the evolution of 4G. Between now and 2020, the year when 5G is scheduled to be commercially available, Advanced LTE networks will seed the market for exciting new applications, such as increasingly autonomous cars, real-time gaming, personal cloud services, dense sensor networks and remote health monitoring. Narrowband IoT and Long Term Evolution (LTE) Machine Type Communications, will enable operators to support the deployment of large numbers of battery-powered IoT devices in licensed spectrum. These networks technologies could enable connected devices to operate for 10 years on a 5Wh battery, reducing the need for in-field maintenance and making key IoT applications, such as smart metering, more cost-effective. Over the next four years, LTE Advanced will be a game changer for both mobile operators and their customers