AT&T's 2.3 GHz WCS spectrum (Band 30) oddly lacking in Apple's new iPhone SE

Unlike its bigger, older sibling, the iPhone SE doesn't support the WCS spectrum that AT&T (NYSE: T) started deploying LTE service in last fall.

But no one is saying why not.

The nation's second-largest mobile operator took control of a large chunk of WCS 2.3 GHz airwaves when it acquired spectrum holding company NextWave in a 2012 deal valued at roughly $600 million. The move combined the nation's two largest WCS spectrum holders, and AT&T last September said it had launched LTE service over those airwaves in a handful of markets.

Meanwhile, handset support for WCS -- also known as Band 30 -- spectrum has gradually increased over the last year. The new Samsung Galaxy S7 devices support it, as did the previous-generation Galaxy S6. Apple introduced support for WCS last year in the form of the iPhone 6s.

But Apple's specs page for the iPhone SE doesn't list WCS among the supported LTE bands. Neither Apple nor AT&T responded to inquiries from FierceWireless regarding its absence.

Carriers deploy services on new spectrum bands fairly regularly, of course, and smartphone designers and manufacturers must weigh a variety of factors when considering what bands their handsets will support and what they won't. The iPhone SE is substantially smaller than the iPhone 6s, of course, so size may have been a consideration, according to Avi Greengart, research director of consumer platforms and devices for Current Analysis.

But not necessarily.

"The physical size of the device is unlikely to be a gating factor, but without comments from Apple or AT&T, it is hard to know what the exact reasoning is," Greengart explained via email. "Untangling why specific frequency bands are included or excluded can be complicated. It could be the specific chipset, antenna tuning, or the cost of testing and then inventorying multiple SKUs."

And the fact that AT&T views WCS as a "capacity layer" may be a factor as well. The carrier is putting it to work in dense, urban areas on top of its 700 MHz and 1700/2100 MHz AWS LTE network. So while it may help ease congestion and deliver faster network speeds, WCS certainly isn't the backbone of the carrier's LTE offering.

Related articles:
AT&T begins deploying 2.3 GHz WCS spectrum for LTE
AT&T expects to start deploying 2.3 GHz WCS spectrum for LTE this summer
AT&T to acquire NextWave--and its WCS spectrum--for $600M