Joint Power Allocation and Route Selection for Outage Minimization in Multihop Cognitive Radio Networks with Energy Harvesting

This paper explores joint power allocation and route selection in a multihop cognitive radio network consisting of secondary transmitter and receiver connected through decode-and-forward relays. A novel frame structure of radio frequency energy harvesting (EH)-cooperation-transmission is considered that operates in time switching mode. The relays also help (cooperation phase) in data transmission between the primary transmitter and receiver using a fraction of the harvested energy. An optimization problem is formulated to minimize the end-to-end secondary outage probability under the constraints of energy causality and primary user cooperation rate. Closed form expressions of the optimal time duration for EH and power allocation factor on each relay are also derived. In order to minimize the total power consumption (cost) and to enhance the network lifetime, the optimal route selection is also explored using Bellman-Ford algorithm and the efficacy of the same over Dijkstra's algorithm is also demonstrated by a large set of simulation results. Simulation results also show that a gain in outage probability ~43.57% and ~56.66% is achieved for the proposed approach over the existing works.