Novel cognitive radio technique for using white space in public cellular networks

In this study, we investigate the potential of cognitive radio systems (CRSs) with the aim of using the white space (WS) in Public Cellular Networks (PCNs). We first clarify the difficulties specific to PCN WS usage and propose a CRS technique with Cognitive-radio Supportive Accommodation System (CSAS) as a scheme to overcome the difficulties. The main concept of the scheme is that CSAS, which is the primary system that owns the frequency band, agrees to support CRS functions required for spectrum sharing. The spectrum sharing scheme is designed on the PCN signal formats so as to suppress inter-system control signal overheads. We outline the prototype devices equipped with the proposed scheme, and some initial evaluation results obtained on an indoor testbed composed of the prototype devices are presented.