As you might expect, application providers and tier one mobile service providers have different answers to the question of how newly-repurposed broadcast TV spectrum should be awarded.

The same difference in thinking applies to many other spectrum assets, in other bands, especially in the 3.5 GHz area that is proposed for new forms of spectrum sharing in the U.S. market.

Mobile service providers, as typically is the case, argue for licensing.

Application providers tend to argue for an unlicensed approach, or when that is not politically possible, lightly licensed and “shared spectrum” approaches that are not exclusive, as preferred by mobile service providers.

“In the 3.5 GHZ band in U.S. market, there are two paths to spectrum abundance: Wi-Fi offload on unlicensed bands,” said Michael Calabrese, Wireless Future Project director at the New America Foundation. ”But longer term, small cells and dynamic spectrum access, especially to licensed government spectrum,” is the solution. That is an example of the “shared” approach, rather than the exclusive licensing model.

And one way of sharing that protects incumbent licensees, provides interference protection for some apps and users, as well as enabling lots of “best effort” access, is tiered access to shared spectrum, where commercial and licensed government users share access.

Using that model, licensed incumbents would be assured that their applications have priority access, when they need it.

But some users could obtain “priority access” that provides interference protection, so long as such usage does not interfere with the license holders use of spectrum. That would be of interest to mobile service providers, who want assurances the spectrum would be consistent in terms of quality.

Finally, other users would have best effort access.

Conceptually, methods of managing interference in shared spectrum bands would look very much like the system proposed for TV white spaces, says John P. Malyar, iconectiv chief architect.

Not surprisingly, Google (News - Alert) takes a different view. In principle, the whole idea behind spectrum sharing is that new spectrum can be found if there is no need to clear licensed users out of their existing bands, then make that spectrum available to other users. Instead, spectrum can be shared between existing licensees and new commercial users.

Where the old model prevented interference by issuing exclusive rights to use spectrum, often specifying what air interfaces could be used, and what applications provided, the newer thinking is that, so long as licensee holders are protected, diversity can reign, said Dr. Preston Marshall, of Google Access.