Media Access Scheme in Distributed Spectrum Sensing

Spectrum sensing is a key component of cognitive radio (CR) system to understand its radio frequency (RF) environment. One critical challenge in spectrum sensing is detection of weak signals in particular in an indoor environment. Distributed spectrum sensing can address this shortcoming by providing a combined data from spatially distributed sensors. This approach often achieves higher sensitivity in comparison to a single standalone sensor by exploiting the inherent spatial diversity of the cooperating sensors. The overall system performance of distributed sensing, however, depends both on the quality of sensing at the individual sensors and the forwarding scheme from the sensors to the data fusion center (FC). In this aspect the choice of appropriate media access (MAC) control plays significant role. We can improve the system performance by optimizing the MAC and the spectrum sensing parameters jointly. In this paper we propose such cross layer approach to yield an enhanced distributed spectrum sensing scheme. To demonstrate our idea, we provide computer simulation by considering energy detection based distributed spectrum sensors and some of the 802.15.4 MAC specification assumptions.