Undetectable Primary User Transmissions in Cognitive Radio Networks

Various metrics related to the protection of primary user in cognitive radio networks, such as the detection probability and collision ratio, have been considered in recent years. In this letter, as a new metric to be used for a constraint to protect the primary user, the concept of undetectable primary user transmission (UPT) is introduced. UPT occurs when a primary user transmission only occurs between two consecutive sensing epochs. The relationship between the frequency of UPT and the sensing interval is derived and evaluated for various conditions.