Prototype of tablet-type TV band portable device with UHF converter for TV white-spaces utilization

Cognitive radio technology, which enables an efficient use of spectrum, is expected as one of solutions for a spectrum shortage problem. Recently, spectrum sharing type cognitive radio technology in TV white-spaces has been actively promoted worldwide and technical specifications have been advanced in international standardization activities such as IEEE802.11af and IEEE802.22. These standardizing systems tend to secure more frequency channels for existing systems by simply converting their native frequency band to TV white-spaces for data traffic offload. As one of the simplest technologies to realize wireless communications in TV white-spaces, we proposed a frequency conversion system using a UHF converter. In this paper, we prototyped a tablet-type portable TV band device, which can communicate in TV band with IEEE802.11b/g-based communication systems by using the UHF converter. Also, physical features of our prototyped tablet terminal are summarized and the RF transmitter and receiver performance and spurious response are characterized.