The International Telecommunications Union has completed the assessment of six 4G mobile wireless broadband candidate standards for the official IMT-Advanced designation that will deliver interoperably, 100 Mbps (mobile) broadband speeds as an official international 4G standard.
Two technologies, “LTE-Advanced1” (based on cellular’s LTE standard) and “WirelessMAN-Advanced2” (based on the WiMAX 802.16m standard), have been accorded the official designation of IMT-Advanced, qualifying them as true 4G technologies.
|Core networks||IP based|
|Data rates||100 Mbps to 1 GHz|
|Access methods||OFDMA, SC- FDMA, OFDM-TDMA|
|Radio Interface||Cognitive radios, software defined radios.|
|Modulation||QPSK, 16QAM, 64QAM, DAPSK|
|Services provided||Rich multimedia, voice, high speed data.|
|Duplex methods||FDD(paired, unpaired), TDD|
|Error control||LDPC, turbo codes, HARQ|
|Handover||Seamless, vertical, horizontal, hard, soft|
The ITU requires 100 Mbps (mobile) and 1 Gbps (fixed) speeds, among other criteria, to qualify as true “4G”. That’s about 3 times the speed of today’s LTE and WiMAX systems.
In its recent meeting in Chongqing, China, ITU-R Working Party 5D, found the LTE-Advanced and WirelessMAN-Advanced technologies successfully met all of the criteria established by ITU-R for the first release of IMT-Advanced.
The official Report is expected to be approved by ITU Member States at the ITU-R Study Group 5 meeting in Geneva in late November 2010.
ITU-R launched the IMT-Advanced (4G) initiative in 2002. Six proposals were received by ITU in October 2009 and individually subjected to a rigorous assessment, supported by the work of independent external evaluation groups around the world. Industry consensus and harmonization fostered by ITU-R among these six proposals have resulted in the consolidation of the proposals into the two agreed IMT-Advanced technologies.
These technologies will now move into the final stage of the IMT-Advanced process, which provides for the development in early 2012 of an ITU-R Recommendation specifying the in-depth technical standards for these radio technologies.
The official IEEE proposal is based on 802.16m, the “Advanced Air Interface” specification, under development by the IEEE 802.16 Working Group, an upwardly compatible evolution of the current Mobile WiMAX standard.
ITU-R’s stringent requirements included four IMT-Advanced “environments”: Indoor, Microcellular, Urban, and High Speed.
The proposals were presented at the 3rd Workshop on IMT-Advanced in Dresden on 15 October in conjunction with a meeting of ITU-R Working Party 5D.
Robert Syputa explains how ITU’s is 4G different and enabling.
By using 4X2 MIMO in an urban microcell, and 20 MHz TDD channel (double the usual 10 MHz), the 802.16m system, for example, supports both a 120 Mbit/s downlink and 60 Mbit/s uplink per site simultaneously, says the WiMAX Forum.
Both WiMAX 2 and LTE Advanced feature a Relay Station option that may prove to be more significant then raw speed. A relay station is like a repeater, providing service for shadow areas without needing dedicated backhaul.