Not content with disinterring the FCC’s infamous October 2010 working paper that most thought had been completely discredited five years ago, last month CTIA went on to commission Brattle Group to produce a new “updated” version of the FCC’s forecasts.
Ironically enough this new report confirms that the FCC was totally wrong in 2010, because the total amount of spectrum in use at the end of 2014 was only 348MHz, not the 822MHz that the FCC projected. Despite this clear demonstration of how ludicrous the original projections were, Brattle reuses the same flawed methodology, which ignores factors such as that new deployment is of cells for capacity not for coverage, and so the ability to support traffic growth is in no way proportional to the total number of cellsites in the US.
Now Verizon’s Q2 results, announced today, highlight another fundamental flaw in the methodology used by Brattle, in terms of the projected gains in spectral efficiency. Brattle assume that the gain in spectral efficiency between 2014 and 2019 is based on the total amount of traffic being carried on 3G, 4G LTE and LTE+ technologies, so with 72% of US traffic in 2014 already carried on LTE, there is relatively little scope for further gains.
This is completely the wrong way to account for the data carrying capacity of a certain number of MHz of spectrum, since it is the share of spectrum used in each technology that is the critical factor, not the share of traffic. Verizon highlighted that only 40% of its spectrum is used for LTE at present, while 60% is still deployed for 2G and 3G, despite the fact that 87% of traffic is now carried on LTE. Of course once that 60% of 2G and 3G spectrum is repurposed to LTE, Verizon’s network capacity will increase dramatically without any additional spectrum being needed.
Brattle’s methodology would suggest that moving the rest of Verizon’s traffic to LTE would only represent a gain of 5% in capacity (assuming an improvement from 0.72bps/Hz to 1.12bps/Hz) but in fact moving all of Verizon’s spectrum to LTE would produce a gain of 27% in network capacity (and an even bigger improvement once LTE Advanced is considered). Adjusting for this error in the methodology reduces the need for more spectrum very sharply, and once it is considered that the incremental cellsites will be deployed to add capacity, not coverage, the need for additional spectrum above the current 645.5MHz is completely eliminated.