Abstract-We investigate joint information and energy cooperative schemes in a slotted-time cognitive radio network with a primary transmitter-receiver pair and a set of secondary transmitter-receiver pairs. The primary transmitter is assumed to be an energy-harvesting node. We propose a three-stage cooperative transmission protocol. During the first stage, the primary user releases a portion of its time slot to the secondary nodes to send their data and to power the energy-harvesting primary transmitter from the secondary radio-frequency signals. During the second stage, the primary transmitter sends its data to its destination and to the secondary nodes. During the third stage, the secondary nodes amplify and forward the primary data. We propose five different schemes for secondary access and powering the primary transmitter. We derive closed-form expressions for the primary and secondary rates for all the proposed schemes. Two of the proposed schemes use distributed beamforming to power the primary transmitter. We design a sparsity-aware relayselection scheme based on the compressive sensing principles. Our numerical results demonstrate the gains of our proposed schemes for both the primary and secondary systems. Index Terms-Cognitive radio, cooperation, energy harvesting, simultaneous wireless information and power transfer. Energy-harvesting schemes extend the lifetime of wireless network nodes. Dynamic and efficient spectrum access can be achieved using cognitive radio techniques. The cognitive radio nodes dynamically and opportunistically access the primarylicensed frequency bands to enhance spectrum utilization efficiency. Recently, efficient integration of energy-harvesting techniques into cognitive radio networks has attracted a significant attention from both industry and academic communities. In [1] , the authors analyze a theoretical upper-bound on the maximum achievable throughput of an energy-harvesting secondary system. A new channel selection criterion for an energy-harvesting secondary system is developed in [2] . Since radio-frequency (RF) signals used for data transmission can also carry energy, simultaneous wireless information and power transfer (SWIPT) has received increased attention from researchers recently. In [3] , the secondary transmitters (STs) harvest energy from the RF signals of the nearby active primary transmitters (PTs). Energy and information cooperation is proposed in [4] where a primary user powers a secondary user which, in turn, relays the primary data. This paper studies joint information and energy cooperation where the
In REF , the primary and secondary rates were investigated in a cognitive radio network composed of a primary transmitter-receiver pair and multiple secondary transmitter-receiver pairs where the primary user releases a proportion of its time slot to the secondary nodes to send their data and to power the EH primary transmitter.
Cooperative Access Schemes for Efficient SWIPT Transmissions in Cognitive Radio Networks
2015 IEEE Globecom Workshops (GC Wkshps)
2015 IEEE Globecom Workshops (GC Wkshps)
Computer Science Mathematics