The United Kingdom's Office of Communications has confirmed that spectrum within three VHF (Very High Frequency) radio bands "can be used for Internet of Things (IoT) services and Machine-to-Machine (M2M) applications." The statement is the result of months of study, during which commentary from stakeholders and interested parties was sought and considered, resulting in a detailed OfCom statement (PDF) titled "VHF radio spectrum for the Internet of Things."
The spectrum bands (55-68 MHz, 70.5-71.5 MHz, and 80.0-81.5 MHz) were already being used for some IoT and M2M applications, along with mobile voice communication. However, the new OfCom statement formalizes these bands as being the spectrum that should be used for Internet of Things services going forward. In addition, OfCom announced that it will be replacing its existing Business Radio License with a new license "that makes specific provision for IoT/M2M, but continues to support current applications."
The 31-page OfCom statement (PDF) includes the following:
- Executive summary: provides background relating to the need being addressed, the process that took place, and the conclusions OfCom reached
- Introduction: provides background on OfCom's objectives ("We want to encourage UK investment and innovation in the Internet of Things") and its role in accomplishing this, and introduces the next two sections of the document
- Consideration of consultation responses: presents the questions that were asked to the stakeholders, and discusses the responses, including quotes from the 12 stakeholders who did not mark their responses as confidential
- Our conclusions and decisions: commentary on the suitability of VHF spectrum for IoT services, OfCom's decisions on licensing, and discussion relevant to potentially-impacted non-IoT users of the spectrum bands
- International harmonisation: discusses the current insufficient international harmonization relating to radio spectra specifically in the VHF bands, and outlines efforts to address this problem
- Technical conditions of BR Licences: selected technical details of OfCom's current Business Radio licenses
- Glossary: explication of acronyms used in the document
Much of the commentary contributed by interested parties was derived from questions and discussion of the technical merits of using VHF frequencies for IoT and M2M mobile communication. Points of discussion included the large antenna size required for VHF communications "and how inefficient antennas are when they are shortened," the impact of ionospheric disturbances that can disrupt VHF communications, and the possibility of interference into neighboring radio bands adversely affecting amateur radio enthusiasts.
The United Kingdom is not alone in seeking to address the radio spectrum requirements for the Internet of Things. Stephen Lawson reports that in the United States "Four U.S. senators have proposed a bill that would call on the Federal Communications Commission to study the need for more spectrum to connect Internet of Things devices."