Wideband sensing of slow FH primary users with unknown hop duration

This paper examines a sensing framework for a multi-channel occupied by a licensed user (primary user) employing slow frequency hopping to access a channel. This method of access presents a challenge to a sensing cognitive radio node because a licensed user effectively spreads its signal over the entire wideband and the spectrum holes are rapidly changing. By adopting a sensing strategy of jointly detecting all subbands in the channel simultaneously, we study the achievable unlicensed user (secondary user) throughput vis-a-vis the allowable interference on the primary network. The investigation assumes no knowledge of the licensed user´s hop pattern or hop duration. In such a scenario, the primary user and secondary user time frames are most likely misaligned, unsynchronised and of unequal durations, which provides for an interesting anlaysis.