Bidirectional channel searching method for opportunistic or cognitive radio

摘要

Scanning for an available channel in a frequency spectrum is performed by a bidirectional scanning method to allow cognitive or opportunistic radio users to access the spectrum while a primary or licensed user is not transmitting. The method comprises a bidirectional search away from an initial channel frequency, which bidirectional search may be a spiral search. The method may include steps to take when a boundary of the spectrum is encountered, for example changing to a unidirectional search away from the boundary or jumping a random amount before recommencing a bidirectional search. The search may also take into account existing information concerning channel reservation.