The FCC Technical Advisory Council’s (TAC) draft white paper on spectrum efficiency metrics (25 September 2011) is an excellent piece of work. It is authoritative, instructive, and demonstrates decisively that spectrum  efficiency metrics are a meaningless concept.
While they don’t say this in so many words, members of the Sharing Working Group perhaps intended this conclusion to be drawn; “spectrum efficiency” is a DC catchphrase that is hard to avoid, and it would probably be unwise to refute it overtly…
The following elements of the paper imply that the “spectrum efficiency” concept is useless:
- There is no metric that can be applied across the myriad of different wireless services.
- The metrics are incomplete, even within a service.
- While the paper suggests metrics for specific services, the taxonomy of services is arbitrary.
- There is no way to compare the “efficiency” of one radio service (aka one “spectrum use”) to another, denying politicians the pseudo-scientific rationale they dream of for converting a frequency band allocation from one use to another.
- Even within a given service type, there is no defensible way to rate one deployment’s performance over another; even if one scored much lower using the relevant efficiency metric, its defenders could invoke any of the long list of “additional efficiency considerations” to deny that the comparison was valid.
The paper also misses an opportunity: It hints at the importance of cost effectiveness rather than mere efficiency, but doesn’t address this broader context.
- From spectrum efficiency metrics to parameter spaces (December 2011)
- Three meanings of “spectrum efficiency” (October 2012)