Ofcom studies options for improving in-building mobile coverage

A study commissioned by UK telecom regulator Ofcom examines tradeoffs among many mobile indoor-coverage technologies, and suggests the agency help consumers learn more about them.

Prepared by the UK consulting firm Real Wireless, the study points to several factors expected to negatively impact indoor mobile coverage over time:

  • Mobile data is increasingly used indoors — about 85% now and trending up.
  • Building attenuation is increasing as a result of improved insulation, including metalized windows (up to 20 dB versus 5 to 10 dB in older buildings)
  • User expectations of an acceptable minimum data rate continue to increase
  • Increased use of higher frequency bands have higher building attenuation
  • Mobile device sensitivity reduces as the number of bands supported increases (by about 1 dB per band)

Countering these trends, the study discusses the rapid development of in-building coverage technologies, including Wi-Fi (both carrier and self-provided), femtocells (home), picocells (offices), repeaters (boosters to those in the U.S.), and distributed antenna systems (DAS).

inbuilddevices

The study looks at the tradeoffs in these devices, in terms of many factors including availability, security, scalability, and evolution — factors identified by Ofcom as important. These tradeoffs get summarized in the following chart:

inbuildsummary

Coverage from outdoor macrocells will continue to improve, helping indoor coverage. They will continue to be an important component in indoor coverage, particularly in smaller buildings, but the study sees an increasing role for dedicated in-building solutions.

Among other recommendations, the study suggests Ofcom develop guidance that will help consumers compare the many in-building options and help them compare — perhaps using a Q&A format on a website, so the consumer gets particular guidance.