When I was recently looking at frequency band assignments to US carriers in the 700 MHz band by the FCC I noticed one thing that, from a European perspective, looks a bit odd. Perhaps somebody can enlighten me?:
LTE bands 12, 13, 14 and 17 in the 700 MHz frequency range are assigned to different network operators and each comes with an individual 20 MHz duplex gap. 10 MHz for uplink, 10 MHz for downlink and 20 MHz for the duplex gap, 40 MHz together. Multiplied by 4, that's 80 MHz for duplex gaps.
In Europe, band 20 in the 800 MHz range that is used by three network operators with 2x10MHz channels each only has a combined duplex gap of 11 MHz. To me that looks a lot more economical then spending 80 MHz for duplex gaps!? But perhaps I am missing something!?
Are those duplex gaps in the US used for anything or are they just wasted space?
Update: Thanks for the comments below, I have followed up on this thanks to them in this post.
Here is a good article on how the US 700MHz band became such a mess. http://www.extremetech.com/electronics/154655-700mhz-mobile-spectrum-a-sad-tale-of-regulatory-and-interoperability-failure
Scroll down on the page you linked for the LTE bands and you will see that the bands are not quite as straightforward as you thought. Bands 12 and 17 are partially duplicative: Band 12 includes the lower A, B, and C blocks, and Band 17 includes the lower B and C blocks, omitting A. Each of the A, B, and C blocks can be a different operator in a given location. The duplex gap in both cases is the same, including the D and E blocks, which are downlink-only (formerly used for QualComm’s MediaFlow).
Band 13 is the upper C block, held by Verizon. Band 14 (misdescribed in the table as the public safety band) is the upper D block, which failed to sell at auction and is in the process of being combined with the immediately adjacent public safety band. Bands 13, 14, and the public safety band are interleaved; there is no vacant spectrum except for the narrow upper A band and the not-yet-used public safety band.
Hi Michael,
thank you very much for commenting! Indeed after reading your explanations I started drawing the bands on a graph and I indeed understood that it is not as straight forward as Band 20 in Europe 🙂
I’ve drawn a graph by hand and will put it into a follow up post which will make things easier to understand, especially where those large pseudo-duplex gaps come from (i.e. interleaving, unsold spectrum and sold but unused spectrum) that I observed and took for ‘real’ ones!
Kind regards,
Martin
Hi Steve,
thanks so much for your reply as well. The story behind the link you supplied is indeed very interesting and sheds some further light on the situation. As said in the other response above, I’ll do a follow up post on this one to summarize this.
-Martin