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Channel selection in cognitive radio networks with opportunistic RF energy harvesting

Radio frequency (RF) energy harvesting is a promising technique to sustain an operation of wireless networks. In a cognitive radio network, a secondary user can be equipped with RF energy harvesting capability. We consider such a network where the secondary user can select one of the channels to transmit data when it is not occupied by a primary user, and to harvest RF energy when the primary user transmits data. Specifically, we formulate an optimization problem to determine an optimal channel selection policy for the secondary user. The secondary user selects a channel based on the energy level in its battery (i.e., energy queue) and the number of packets in its data queue. The optimization considers complete information and incomplete information cases, where the secondary user has and does not have the knowledge about channel states, respectively. The performance obtained in the complete information case can serve as an upper bound for the secondary user.