Long Term Evolution Advanced (LTE-Advanced) is a wireless communications technology primarily intended to bring higher data rates to mobile phones and other devices. It is a revised version of LTE updated to be fully compatible with the fourth generation, or 4G, family of wireless standards. LTE-Advanced uses some sophisticated techniques to bring speeds of up to a gigabit per second to end users while preserving compatibility with older systems.
Different wireless and cellular telephony technologies are often grouped into generations: early analog networks were a first generation or “1G” technology; the first digital networks were part of a second-generation known as “2G;” and more modern networks with higher data rates were considered “3G.” While wireless service providers often use these labels for marketing purposes, they are really umbrella terms that can cover a wide variety of technologies.
LTE-Advanced is a revision meant to bring earlier LTE technology into full compliance with the fourth generation or “4G” family of wireless technologies as defined by the International Telecommunication Union’s Radiocommunication Sector (ITU-R). The ITU-R’s 4G specifications, which the group formally refers to as International Mobile Telephony Advanced (IMT-Advanced), call for theoretical peak data rates of 100 megabits per second (Mbps) under high mobility situations or 1 gigabit per second (Gbps) in fixed or low mobility environments. Early revisions of both LTE and WiMAX®, although touted as 4G by some carriers, do not meet the requirements of IMT-Advanced and are more appropriately be called "pre-4G" or "3.9G" technologies.
In order to achieve higher data rates while preserving compatibility with older LTE standards, the designers of LTE-Advanced had to use some relatively advanced techniques. Larger amounts of radio frequency spectrum may be utilized in addition to new techniques for more efficient use of limited spectrum. Devices compatible with the new technology are likely to feature a number of antenna arrays, and a process called beam-forming can turn would-be interference into a tool to boost signal.
Using a scheme known as carrier aggregation, a cellular base station can break apart a stream of data and transmit it through multiple radio frequencies to a user’s device, which then reassembles these multiple pieces into the original data stream. Another technique known as coordinated multipoint transmission/reception employs multiple base stations to simultaneously send and receive data to a single device. This can be especially beneficial to customers who are on the edge of a particular base station’s coverage area; by combining two base stations, a faster and more reliable connection can be achieved. Multiple LTE-Advanced base stations can even be used in a relay, with each base station transmitting information to the next.