Provided by: Hindawi Publishing
Date Added: Jul 2010
Under interference constraint and energy consumption constraint, to maximize the channel utilization, an Opportunistic Spectrum Access (OSA) strategy for a slotted Secondary User (SU) overlaying an unslotted ON/OFF Continuous Time Markov Chain (CTMC) modeled primary network is proposed. The OSA strategy is investigated via a cross-layer optimization approach, with joint consideration of sensing period (related to PHY layer) and transmission time (related to MAC layer), which will affect both interference and energy consumption. Two access policies are investigated in this paper; that is, SU transmits only in "OFF slots" (i.e., the slots that the sensing results are OFF) and transmits in both "OFF slots" and "ON slots."