FCC Chairwoman Jessica Rosenworcel announced Tuesday at Mobile World Congress in Barcelona that the US government agency will auction off spectrum in the 2.5GHz band in July for use in 5G networks, paving the way for telecom companies to further expand their midband holdings.\nThe 2.5GHz auction represents the pending sale of what Rosenworcel called \u201cthe biggest swath of contiguous midband spectrum we have available below 3GHz,\u201d and will be followed by a further auction of midband spectrum in the 3.1GHz-3.45GHz range.\nThe FCC has had plans for this auction in the works for more than a year, having first sought public comment in January of 2021. The auction will cover roughly 200MHz of spectrum, and will be sold on a per-county basis, according to the earlier request for comment.\nThe incumbent users in the band represent a unique challenge for the FCC, according to IDC research manager Jason Leigh. Some of this spectrum has been allotted to users of the Educational Broadband Service, which was sold to educational institutions and gives them the rights to those airwaves in a 35-mile radius around a fixed point.\n\u00a0\u201cThe challenge \u2026 is that [the licenses] are not uniform,\u201d Leigh said. \u201cEvaluating the value and population coverage for each license is going to be tricky for bidders.\u201d\nLeigh said that it appears the FCC will let EBS users keep their existing licenses or lease them out as they see fit.\nThe auction will be the latest in a series that has seen the FCC sell off large chunks of midband spectrum \u2014 generally defined as being between 1GHz and 6GHz \u2014 for the purposes of accelerating 5G deployment in the US. The last such auction, whose bidding phase concluded in November, took in nearly $22 billion in exchange for spectrum in the 3.45GHz band.\nWhile most of 5G\u2019s most show-stopping capabilities will be achieved through the use of higher frequencies in the so-called \u201cmillimeter wave\u201d bands above 24GHz, mid-band spectrum allows for much wider coverage per access point, since lower-frequency radio waves propagate much more easily over distance. The trade-off is that, because there\u2019s much less spectrum available for 5G use in those lower bands, there\u2019s less available space for the wide channels that allow for very high throughput.\nHence, the midband is often referred to as the \u201cGoldilocks zone\u201d for 5G, as it strikes a balance between signal range and channel availability, and helps explain both why the FCC has pushed to make more of it available and why the carriers have paid so much for the rights to that spectrum. The C-band auction, which sold spectrum in the 3.7GHz range and closed in early 2021, took in nearly $81 billion.