MARAVEDIS

The primary difference between LTE and WiMAX are the diffferences in upbringging: like close cousins, there are deep blood ties between the two standards, (similar frameworks of technology), but the 'families' that have raised them are different: different goals and different means. But as each group has now prepared their standards to fulfill proposal requirements mandated by ITU, International Telecommunications Union, IMT-Advanced, the two standards are seeking jobs at the same huge 'factory' - the factory of open IP unified communications.

Both WiMAX and LTE have evolved to become 'evolutionary frameworks' that are based on the same core wireless and network technologies. Many of the differences can be viewed as specializations upon that core theme:

WiMAX has its roots in the wireless broadband access industry which had used a hodge-podge of non-standard technologies. For that matter, WLAN, wireless local area networking, had been a mix of mostly proprietary approaches until the success of of the IEEE 802.11b/a standard. The IEEE 802.16 effort had been underway and produced its first version of the standard, but until the powerful semiconductors become available at low cost to enable WiFi based on 802.11 to explode in popularity, the 1st version gained little adoption, even among the developing companies.

Success in WiFi helped speed the development of chip designs and clarified what was possible to develop in WWAN, wireless wide area networks. Not alone, Flarion/Qualcomm, and companies providing mobile systems also had considered the day when it would become feasible to use MIMO-OFDM and other advanced technologies. But the 3GPP/3GPP2 efforts also considered other technologies including layering of OFDM on top of WCDMA (wonder why? ; ^).

So, when the discussion is about 'What is WiMAX (or LTE)' the answer should also include a statement that "these are two systems developing along the same lines but optimized to work somewhat differently. WiMAX is primarily aimed at Greenfield (new) fixed to mobile deployments while LTE is mostly aimed at incumbent (existing) deployments that must work with existing networks and business practices".

But you can quickly see even that is a simplification that does not completely fit the current state of development: Sprint now sells dongles with mobile devices soon to appear that will support both Clearwire's WiMAX and Sprint's 3G EVDO. And they are working on doing seamless hand-offs of voice and other communications. That will soon mean users of Google Android or other phones and mobile devices will be able to start a VoIP call on the WiMAX network and keep on talking as they travel to a Sprint or collaborating 3G network. Chips are in the works to also allow that to happen across WiMAX and HSPA/GSM.

Likewise, some LTE developers say it will be used for fixed networks as well as for mobile networks.

The next versions of both, 802.16m WiMAXm and LTE-Advanced, are being designed to meet the same guidelines for IMT-Advanced which calls for an adaptive framework that can be used from local area fixed networks to large scale mobile networks and to use multiple carriers across multiple bands of spectrum. No sense getting into the details but it is important to view both WiMAX and LTE headed to become the 'Swiss Army knives' of wireless. Should they merge? They are already on the path of converging at many levels and will eventually be practically merged.

Robert Syputa