Mary Brown on Building a Spectrum Pipeline


Mary Brown visits the High Tech Forum Podcast for episode 61 on spectrum policy. Mary testified at the recent Congressional hearing titled “5G and Beyond: Exploring the Next Wireless Frontier” on questions about spectrum auctions, licensing, government coordination, and innovation. Mary is Cisco’s Senior Director of Spectrum Policy and a veteran of the Commerce Spectrum Management Advisory Committee and the FCC.


  • The spectrum allocation status quo assigns most of the spectrum from 1 GHz to 4 GHz to licensed uses, with some significant exceptions: 100 MHz at 2.4 GHz is used by Wi-Fi and Bluetooth, and 150 MHz in the lower part of the 3 GHz band is used for CBRS. Most of the 5 and 6 GHz bands are unlicensed (used by Wi-Fi) although most of the 6GHz band has licensed outdoor users. Future bands that can and should be allocated shortly include: the 4GHz band used in Asia for 5G (and probably 6G in due course); the 7 GHz band that can be used either by Wi-Fi or by 5G and 6G; and the 12 GHz band currently used by satellites. (5:28)
  • 5G propagation models need to get better fast. Conflicts over the use of 5G mid-band antennas near airports largely developed because the aviation industry didn’t have access to good models of mid-band propagation by 5G systems, a critical piece of the controversy. Much of the 5G propagation modeling work already done focused on mmWave bands, but it’s now clear that the mid-band is where the action is for the immediate future. These models need to be accessible to commercial users as well as government agencies and telecommunications carriers. (28:19)
  • Evaluation of 20th century radio use cases against 21st century networking needs has to become an ongoing process until all of the spectrum allocations made by fiat are converted to more general uses. This can be done by upgrading applications to use general-purpose networks (where possible) and then either auctioning flexible use licenses or by releasing spectrum rights according to a kind of transmitter regulation regime similar to the ones developed for unlicensed spectrum today. Exclusive use licenses provide the ultimate in efficiency, but there are many instances in which users and service providers are willing to sacrifice reliability for lower prices. (45:52)


Our conversation is wide ranging, covering all of the following and more:

  • The evolution of spectrum license auctions (1:45)
  • The current state of spectrum allocations (5:28)
  • Ongoing innovation in radio-based systems (8:59)
  • Where spectrum comes from (9:07)
  • Commerce Department/NTIA Institute for Telecommunications Sciences (15:53)
  • The FAA/FCC controversy about 5G near airports (17:34)
  • The atrophying inter-agency collaboration muscle (26:17)
  • 5G propagation models need work (28:19)
  • Applications for licensed and unlicensed networks (33:38)
  • 5G experiments with in unlicensed spectrum (38:49)
  • Private 5G networks (41:49)
  • Building a better spectrum pipeline (45:52)
  • Realigning historical spectrum grants with current needs (47:00)
  • Spectrum evolution (53:50)