Mapping Cognitive Radio System Scenarios into the TVWS Context

Cognitive Radio has been one of the key research topics in the wireless community for about 10 years. The digital switch-over in the TV bands provides opportunities for Cognitive Radio Systems (CRS) to operate in the 470–790 MHz spectrum under incumbent protection restrictions. Locally unused spectrum in this band is often referred to as TV whitespace (TVWS). Regulatory bodies, in particular the US Federal Communications Commission (FCC) and Ofcom in the UK, have specified parameters under which CRS shall operate. In this paper we analyse key scenarios for CRS stemming from the QoSMOS project. We then analyse how these scenarios can be mapped into the TV whitespace (TVWS) context by considering link budget computation based on FCC and Ofcom transmit power recommendations plus statistical propagation models for the UHF band. We also consider the expected capacity which can be achieved when using TVWS as a capacity extension in an LTE network. We also show how cognitive femtocells can be used to provide outdoor coverage when deployment is based on random location. We eventually conclude on the most promising scenarios in the context of the TVWS usage.