Tuesday 22 May 2007

LTE in few words

Before it gets out from my mind. People keep on asking what LTE is without going in the details. So here it is:

3G LTE, as proposed in 3GPP Release 8, aims to increase cell data capacity by at least five times over the current implementations of HSPA. It will support more users per cell, as well as higher speeds to individual users, and is intended to match DSL speeds currently available to the home. A simplified protocol structure and re-definition of the functional split between network elements and basestations is intended to raise efficiency while making all VoIP networks possible.

Some of the highlights of LTE are:
  • OFDM-based air interface (Orthogonal Frequency Division Multiplexing) ... WCDMA is out.
  • Channel bandwidths from 1.25 to 20MHz are supported
  • Increased spectrum efficiency and peak data rates at cell edge.
  • Target peak rates of 100 Mbps/DL and 50 Mbps/UL. (Nokia-Siemens have already achieved 108Mbps though)
  • Increased spectrum efficiency and peak data rates at cell edge.
  • Reduced latency for both user and control plane: less than 10ms round trip delay for user plane between UE and the serving RAN node, less than 100ms transition time for control plane between inactive state and active state.
  • Support for diversity and MIMO

The first LTE-based networks are expected to roll out in 2009/2010. In contrast to other cellular technologies, conformance tests for LTE are expected to be available more than two years ahead of any service introduction according to Agilent. This will ensure user devices are available in volume when the network services are finally launched.

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