IEEE 802.11af-based baseband IC prototype enabling compact and low power consumption TV white-spaces devices

Since the FCC stated a policy on unlicensed use of the TV white-spaces (TVWS) in November 2008, a number of countries and regions have studied utilization of the TVWS, and some communication systems using the TVWS have been globally discussed and standardized. It has been three years since the IEEE 802.11af has been standardized, while the IEEE 802.11af-based system is not yet applied for commercial deployment due to some difficulties, such as downsizing and power-saving. An integration of the baseband (BB) signal processing circuit is one of the promising technologies that relieve these concerns as well as conventional communication systems. In this paper, the authors have prototyped the world's first IEEE 802.11af-based BB IC, and developed and characterized a card-type TVWS device with sufficient small size and low power consumption by implementing the prototype BB IC. Transmission spectrum conforms to spectral masks regulated by the Ofcom and the FCC with an output power of +20 dBm and +16 dBm, respectively. Transmission performance was also evaluated and a maximal throughput of about 3.0 Mbit/s was obtained in MCS3. From these results, it was confirmed that the prototype BB IC is substantially operating based on the IEEE 802.11af system and the card-type TVWS device allows practical use in major leading countries.