UK telecoms regulator Ofcom said it is becoming “increasingly difficult” to find significant amounts of additional spectrum that can be fully cleared for Wi-Fi and mobile broadband, particularly in the desirable part of the spectrum below 6 GHz.

The warning comes in a newly-published consultation document which also warns about a growing demand for more Wi-Fi capacity not just for indoor wireless networks but also for offload from mobile networks.

The Wi-Fi warning from Ofcom echoes the conclusions of a recent study by the European Commission which recommends more spectrum be set aside for Wi-Fi.

There will also be a heavy increase in demand for mobile broadband and M2M capacity, said the document.  Research commissioned by Ofcom found that under a mid-range estimate there will likely be an 80 times increase in the demand for mobile data capacity by 2030.

In answer to its own question, “Is more spectrum required for Wi-Fi use?” the UK regulator answers that additional spectrum in the 5 GHz band may be needed. In addition to supporting increased use of Wi-Fi and offload, there be a need to use capacity for matching higher fixed broadband speeds.

Wi-Fi operates in the 2.4 GHz and 5 GHz bands.

Ofcom raises the spectre of “a future tragedy of the commons” as the increased deployment of outdoor Wi-Fi small cells “could cause increasing levels of interference and reduced quality of service”.

“This has implications for the future viability of Wi-Fi in both public networks and potentially for outdoor M2M applications,” adds Ofcom.

The aim of Ofcom’s consultation is to develop a better understanding of whether spectrum sharing offers a potential solution.

The drawback to spectrum sharing is it might lead to greater interference between different groups of spectrum users compared to using allocated spectrum bands.

However, advances in dynamic spectrum access (DSA) technology offer hope. DSA technology might enable devices to minimise interference by acting more intelligently in regard to areas such as frequency and power level.