Topic：Information and Energy Cooperation in Cognitive Radio Networks with Energy Harvesting Primary Receiver

Date&Time：2015/11/06(五) 14:20

Speaker： 曾凡碩 教授 (中山大學)

Location：清華大學台達館 R216

Abstract :
In traditional cognitive radio networks (CRNs), the primary users (PUs) and secondary users (SUs) cooperate in order to exploit the spectrum resources more efficiently. In this talk, we will introduce a new CRN, in which an energy-harvesting (EH) device is additionally deployed at the primary receiver (PR) such that the primary and secondary systems can not only share the spectrum resources, but also harvest energy. Cooperative schemes are proposed for maximizing the information-transfer efficiency and energy-harvesting efficiency within the network given an interweave CRN structure and an overlay CRN structure, respectively. In developing the proposed schemes, the interweaved CRN utilizes a time-splitting EH at the PR, while the overlay CRN adopts a power-splitting EH device. For the interweave scheme, the study jointly optimizes the beamformer at the secondary transmitter (ST) and a time-splitting factor for the PU. Meanwhile, for the overlay scheme, the study optimizes two precoders at the ST (for the PU and SU, respectively) and the power-splitting factor for the PR. For both cooperative schemes, the optimization problem is non-convex. Accordingly, to facilitate the optimization process, a precoding structure is first defined to reduce the number of parameters. The resultant optimization problem is then solved using a semidefinite relaxation (SDR) approach. The numerical results show that both schemes provide a promising approach for maximizing the information transfer and energy harvested within the network. The results also exhibit that the overlay scheme provides a better performance since power-splitting provides a more flexible approach than time-splitting for achieving a compromise between information acquisition and energy harvesting.