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LTE (Long Term Evolution) is a standard for 4G wireless broadband technology that offers increased network capacity and speed to mobile device users.
LTE offers higher peak data transfer rates -- up to 100 Mbps downstream and 30 Mbps upstream. It also provides reduced latency, scalable bandwidth capacity and backward-compatibility with existing GSM and UMTS technology. Future developments could yield peak throughput on the order of 300 Mbps.
The 3rd Generation Partnership Project (3GPP), a collaborative industry trade group, developed GSM, a 2G standard; UMTS, the 3G technologies based on GSM; and, eventually, LTE. 3GPP engineers named the technology Long Term Evolution because it represented the next step in the process.
Despite the development of GSM in the late 1980s, there wasn't a globally unified standard for wireless broadband. GSM caught on in parts of Asia and Europe, but other countries, including the U.S. and Canada, adopted the competing standard, code-division multiple access (CDMA). LTE aimed to merge a fragmented market and offer a more efficient network for network operators.
In 2004, NTT DoCoMo, a major mobile phone operator in Japan, proposed making LTE the next international standard for wireless broadband. During a live demonstration two years later, Nokia Networks simultaneously downloaded HD video and uploaded a game via LTE.
Ericsson, a Swedish telecommunications company, demonstrated LTE with a bit rate of 144 Mbps in 2007. At Mobile World Congress in 2008, Ericsson demonstrated the first LTE end-to-end phone call. That same year, LTE was finalized. In 2009, TeliaSonera, a Swedish mobile network operator, made the service available in Oslo and Stockholm.
How large LTE is around the world
Various telephone companies launched LTE at different times in different countries. Some European countries adopted the standard as early as 2009, while North American countries adopted it in 2010 and 2011. As of this writing, South Korea has the best LTE penetration with 97.5% of the country covered by LTE service. The U.S. has 90.3% LTE penetration.
Outside of the U.S. telecommunications market, GSM is the dominant mobile standard, covering more than 80% of the world's cellular phone users. As a result, HSDPA and LTE are likely the wireless broadband technologies of choice for most users.
Voice-over-LTE (VoLTE) is a new technology with which users can place phone calls over the LTE network as data packets instead of as typical phone calls. This is called packet voice, and it can share packets along a network of several phone conversations.
VoLTE can support many callers and reallocate bandwidth as needed to support it. Pauses in conversation on phone calls won't waste bandwidth. Packet voice also allows the user to view if the person they intend to call is currently busy or if their phone is available.
Nortel and other telecommunications infrastructure vendors are focusing significant research and development efforts on the creation of LTE base stations -- or equipment that enables devices to wirelessly communicate with a network -- to meet the expected demand. When implemented, LTE has the potential to bring pervasive computing to a global audience with a seamless experience for mobile users everywhere.
Users enjoy the benefits of the LTE standard compared to older standards, such as 3G and HSPA. Users can see improved streaming, downloads and even uploads. Globally, the average LTE download speed is 13.5 Mbps.
As a result, mobile device carriers can expect consumers to burn through data more quickly, which can lead to overage charges on data plans. LTE can also connect consumers with services in real time. Users can talk to others without experiencing any lag or stutters.
The upper layers of LTE are based on TCP/IP, which will likely result in an all-IP network similar to the current state of wired communications. LTE supports mixed data, voice, video and messaging traffic.
LTE uses OFDM (orthogonal frequency division multiplexing) and, in later releases, MIMO (multiple input, multiple output) antenna technology similar to that used in the IEEE 802.11n wireless local area network (WLAN) standard. The higher signal-to-noise ratio (SNR) at the receiver enabled by MIMO, along with OFDM, provides improved wireless network coverage and throughput, especially in dense urban areas.
LTE Advanced (LTE-A), which was meant to improve the current standard, was first tested in 2011 in Spain. LTE-A improves upon the radio technology and architecture of LTE. LTE-A has been tested to show that the download and upload speeds are around two to three times faster than standard LTE. 3GPP made sure that all LTE-A devices would be backward-compatible with standard LTE.
LTE-A supports carrier aggregation for improved speed and reliability. Carrier aggregation improves network capacity by adding more bandwidth of up to 100 MHz across five component carriers with 20 MHz bandwidth each. LTE-A handsets combine frequencies from multiple component carriers to improve signal and speed.
LTE-A requires devices with a special chip designed to work with LTE-A. Qualcomm, Nvidia and Broadcom all manufacture chips that support LTE-A.
Many new flagship mobile devices support the standard. Apple supports it on the iPhone 8 and above. Many Google Android phones released in the last year support the standard, as well.