UMA Today: To get started, what is LTE and
what are the framers trying to accomplish with
the effort?
Patrick Tao: LTE, or "long term evolution" is the next
generation of 3GPP-based radio access technologies. The
LTE vision is a flat IP network with very high broadband
data rates. Some of the high level goals include supporting
download data rates of 100 mbps, with packet latency
under 5 milliseconds and supporting VoIP on the access
network.
For operators and subscribers alike, LTE promises to
open up the "mobile internet," where voice, video and data
are available instantly to anyone, anywhere. LTE is often
discussed in conjunction with a new IP-based service core
network known as System Architecture Evolution, or SAE.
UMA Today: What is the relationship between
LTE and existing RAN technologies like GERAN
(GSM) and UTRAN (UMTS/HSPA)? How will
operators likely deploy LTE?
Tao: LTE is designed to take advantage of the latest
in radio technologies like OFDM (orthogonal frequency-
division multiplexing), as well as MIMO (multiple-in,
multiple-out) antenna technology to improve throughput
and performance.
In terms of deployment, it's not clear if operators will
gain new frequency bands for LTE or have to re-farm
existing GSM and UMTS frequencies.
While there are operational efficiencies that come
with an all IP access network, the massive installed base
of circuit GSM and UMTS networks and services cannot
be abandoned. Therefore, a key element of LTE, as with
other 3GPP RAN specifications, is mobility and service
transparency between access networks.
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