LTE on track to be finalized this year, with WiMAX2 on the horizon
Published: 29 January, 2008
There are multiple trials of pre-standard LTE systems now underway, with NTT DoCoMo the most advanced (working with Nokia Siemens and Panasonic). Most are taking place under the LTE/ SAE Trial Initiative, in which companies such as Alcatel-Lucent, Ericsson, Orange, Nokia, NSN, Nortel, T-Mobile and Vodafone are involved.
On the WiMAX side, then, there is renewed talk about 802.16m, which will aim to leapfrog LTE and reassure Mobile WiMAX adopters of a long term growth path for the platform. Among the parties aiming to contribute to the 802.16m air interface standard is a new initiative set up under the auspices of the European Commission's Framework Programme 7 (FP7) for future mobile communications systems and IMT*Advanced (the successor to IMT2000, the international set of standards authorized for 3G).
The WiMagic project will incorporate seven technology partners, including French WiMAX chip start-up Sequans, and six universities. WiMagic will work on a new air interface for WiMAX, which will be submitted to the IEEE 802.16m committee. Wi- Magic (Worldwide Interoperability for Microwave Broadband Access System for Next Generation Wireless Communications), has been accepted by the European Commission within the 7th Framework Programme for Research.
The project will address physical layer functions such as MIMO, high performance synchronization and channel estimation techniques for high vehicular mobility; and MAC functions such as adaptive radio resource management. WiMagic will last for three years and sits alongside numerous FP7 projects related to next generation radio networks (see diagram). Among these is MIMAX, which is looking to develop a low power, low cost MIMO platform based on a new way for combining and adaptive weighting of the antenna signals in the RF/LO front end. MIMAX also starts this month and will last for three years.
The IEEE, which creates the 802.16 specifications, has been careful to say that 802.16m would not necessarily equate to WiMAX - it would have to be adopted and approved by the Forum first. In theory, the technical deliberations over 802.16m should not be over-influenced by the commercial needs of the WiMAX industry, though in practise the two are virtually inseparable (WiMAX profiles are subsets of the 802.16 standards, but the Forum is the only major 'customer' for these IEEE standards.) WiMAX Forum president Ron Resnick said in a recent interview that "802.16m is WiMAX and always will be".
Although he would like WiMAX to work more closely with 3GPP bodies and with larger standards organizations like ETSI - especially since being approved as an IMT2000 platform last year - he does not see it converging fully with the UMTS/LTE roadmap.
One of the key enhancements 802.16m offers is greater scope in terms of channel bandwidths than 802.16e, with support for 20MHz and even 40MHz channels and a greater focus on FDD mode. Based on using enhanced OFDMA and antenna techniques (including 4x4 MIMO) in wider channels, it should be able to deliver theoretical downlink speeds of 350Mbps, with 200Mbps in the uplink, and mobility up to 350 kilometres per hour (802.16e boasts peaks of 128Mbps, 28Mbps and 120kmph respectively).