(Long Term Evolution) The latest high-speed
cellular data transmission network. LTE is a 4G technology, surpassing
the speeds of the widely used 3G networks. Apple aficionados eagerly
awaited the iPhone 5 because it was the first iPhone to support LTE.
Available for the two major cellphone systems worldwide (GSM and CDMA),
LTE is envisioned to provide global interoperability. However, LTE
operates in more than three dozen frequency bands, making it difficult
to build a phone that can tune in that many channels.
Approved in 2008 with download speeds up to 173 Mbps, LTE uses a different air interface and packet structure than 3G. See cellular generations and 3G.
LTE - From 3G to 4G Officially
The ITU previously designated LTE-Advanced (LTE-A) as the true 4G
evolution. However, in late 2010, it widened its definition to include
regular LTE, along with WiMAX and HSPA+, as bona fide 4G technologies
since they are faster than 3G. See IMT-Advanced.
E-UTRA/OFDMA, IP and IMS
LTE uses the Evolved UMTS Terrestrial Radio Access (E-UTRA) air
interface, which is based on OFDMA and is a departure from CDMA and the
TDMA used in GSM (see GSM and CDMA).
In addition, rather than proprietary packet structures, LTE is based
entirely on IP packets, and voice travels over IP (VoIP). The IP part
of LTE is called "Evolved Packet System" (EPS), which was previously
called "System Architecture Evolution" (SAE). LTE was defined by the 3G
Partnership Project in the 3GPP Release 8 specification. See IP Multimedia Subsystem.