Dynamic frequency hopping vs. non-hopping in IEEE 802.22 systems

IEEE 802.22 is the first worldwide wireless standard based on Cognitive Radio (CR) for Wireless Regional Area Networks (WRAN). Usually, Secondary Users (SUs) have to be interrupted periodically for spectrum sensing so as to avoid interference to Primary Users (PUs) operating in the licensed bands. Such interruptions of data transmission, however, impair the Quality of Service (QoS) of SUs. Dynamic Frequency Hopping (DFH) has been proposed for IEEE 802.22 system. In DFH, data transmission is performed in parallel with spectrum sensing without interruptions. In this paper, we compare this hopping mode with non-hopping one by computer simulation, the results show that although hopping mode requires a little more channels, it can reduce the collision with PUs and achieve higher ratio of valid delivery and higher throughput, thus provide enhanced QoS for SUs.