Clearwire and Sprint Nextel have been dropping clear hints that Clearwire could adopt Long Term Evolution as an air interface, either alongside its existing WiMAX network or as an eventual replacement.
Since the U.S. wireless industry has been through technology transitions before, it isn't hard to suggest how it might happen, and when. Companies have had to make transitions from one air interface to another within a single generation of technology, as well as migrating customers from an older generation to a new generation.
Where one air interface is switched out in favor of another within a technology generation, the trick is to add all new customers to the new interface while allowing the legacy base of customers to dwindle through attrition. At some point, the old network then can be shut down without undue disruption.
Where an older generation network is replaced by a next-generation network, additional spectrum also is required. If Clearwire wants to shift air interfaces within the fourth generation, it would maintain current customers on WiMAX, while creating a new LTE network alongside WiMAX, signing up new customers on LTE, and allowing WiMAX customers to gradually shrink through attritiion.
That suggests Clearwire will not want to wait too long, as it will want to limit the number of WiMAX customers it has to support while the LTE network is populated with customers.
As an operational matter--and there are other issues to consider--moving sooner is better than moving later, especially given the larger number of customers now coming onboard on the WiMAX network because of the popularity of the Evo.
On the other hand, abrupt action is not required, or even preferable, as the practical details of interworking between LTE and WiMAX, in the core of the network, will have to be proven, in a full deployment mode.
Handset suppliers will also need some time to ready suitable handsets that interwork, as devices now can use either the 2G and 3G networks, or 3G and 4G networks. Alternatively, Clearwire could encourage single-network devices.
With most consumers on two-year contracts, and a natural handset replacement cycle that runs two to three years, customers can be moved to LTE as they replace their current WiMAX devices.
The point is that Clearwire has plenty of spectrum, and industry executives have lots of experience with technology transitions. It will take some planning, and some time, but it is a normal and expected part of the business that air interfaces and networks are changed, at least every 10 years, and sometimes sooner, for other business reasons.
