An increase in the power which can be transmitted over the licence-exempt 2.4GHz band is being recommended to regulator Ofcom as it is considered that the benefits outweigh the costs of interference.

A report for Ofcom by a consortium led by Scientific Generics also recommends an increase in power in the 5.xGHz band. It found that the business case for rural wireless Internet service providers (WISP) is “marginal under the current regulations” at both 2.4GHz and 5.8GHz.

“Increased availability of ADSL has eroded the ability of WBA to compete for residential subscribers, and in rural areas the cost of extending existing networks to reach the more valuable business customers can be prohibitive,” said the report.

However, the report also said: “many interviewees expressed resistance to increasing power at 2.4GHz because of concerns about interference with wireless LANs.”

At 2.4GHz, interference is expected between high power WBA and wireless LAN. WBA operators avoid using the band in urban areas or business parks because of it.

The main concern at 5.8GHz is interference with fixed satellite services (FSS) and radars.

The current regulations allow a maximum EIRP (equivalent isotropic radiated power) of 100mW at 2.4GHz, and 2W at 5.8GHz for WBA.

The report suggests this should be changed so it is regulated by conducted power and antenna gain. At 2.4GHz, 50mW total conducted power and an antenna gain of 3dB is suggested. At 5.0GHz to 5.9GHz, it would be conducted power of 250mW with a maximum antenna gain of 20dBi.

Ofcom is also examining the possibilities for making more use of the 60-100GHz band due to the increasing congestion in the lower bands.

Applications at these frequencies have to be short-range as signals are blocked by rain, but they can carry high data rates. Possible uses include wireless LAN and backhaul for Mesh, branch and tree networks.

Ofcom
Scientific Generics