Two-slope path-loss design of energy harvesting in random cognitive radio networks

There has recently been substantial interest in applying the principles of wireless radio frequency energy harvesting in battery-operated devices to cognitive radio networks. Although implementation of energy harvesting technique increases the complexity of network planning, it reduces battery power usage and enables eco-friendly cognitive radio network. In this paper, we report a comprehensive study of energy harvesting cognitive radio network where locations of users of primary and secondary networks follow a Poisson point process. In the design of random cognitive radio network, we focus on the two-slope path-loss function so as to have a realistic scenario of propagation environments. First, a new expression of outage probability is theoretically derived for secondary receiver in active mode. Second, we obtain an explicit expression of harvested energy for secondary receiver in active and inactive modes. Finally, we investigate the harvested energy maximization problem under a particular outage probability constraint, and also obtain an optimal solution of transmission power and density of secondary transmitters. Numerical results for outage probability, harvested energy, and maximization of harvested energy are presented for evaluation of the performance and characteristics of this network.