Simultaneous Wireless Information and Power Transfer for Dynamic Cooperative Spectrum Sharing Networks

Abstract

In this paper, we provide a comprehensive performance analysis of simultaneous wireless information and power transfer (SWIPT) for cognitive relay networks with different relay schemes. In the considered system, the energy-constrained secondary transmitter harvests the energy from the primary signal and then employs the harvested energy to forward the primary signal along with the secondary signal simultaneously. To improve the spectral efficiency, we propose a novel cooperative spectrum sharing protocol with dynamic time-slot allocation based on energy harvesting, namely, dynamic time-power-based cooperative spectrum sharing protocol. Considering the delay-limited transmission mode, we analytically derive the exact closed-form expressions of outage probabilities and achievable throughput for both the primary and secondary networks with amplify-and-forward and decode-and-forward relaying schemes, respectively. More importantly, different from the existing works, we take into account the power outage probability at the energy-constrained secondary transmitter to better match the reality. Finally, the numerical results are provided to evaluate the effect of different key parameters on the system performance, which demonstrate that the dynamic cooperative spectrum sharing protocol improves the outage performance compared with the uniform time-slot allocation scheme. INDEX TERMS Cognitive relay networks, cooperative spectrum sharing, SWIPT, energy harvesting, outage probability.

Subcarrier Allocation Based Cooperative Spectrum Sharing with Wireless Energy Harvesting in OFDM Relaying Networks

“…CRN splits a fraction of received power with ratio λ to decode information, and another fraction with ratio (1−λ) to harvest energy. Then the harvested energy at CRN is given as E=true∑k∈K12(1−λ)ηpp,k||hPT−CRN,k2+ps,k||hCSN−CRN,k2+σ1,k2 where η denotes the energy conversion efficiency, which utilizes linear energy harvesting model [23,24,25,26,27,28,29].…”

“…Simultaneous wireless information and power transfer (SWIPT) technology has the ability to realize simultaneous information decoding and energy harvesting by receiving radio-frequency signals [16,17,18,19,20,21,22]. Integrating SWIPT with cooperative relaying spectrum sharing enables the cognitive relay to harvest the energy by receiving the primary signal simultaneously with information decoding, which makes the cognitive relay volunteer to forward the primary signal [23,24,25,26,27,28,29]. Reference [23] analyzes the outage probability of primary and cognitive users for two-way cognitive system based on SWIPT relaying, where the cognitive user uses the decode and forward (DF) protocol to help the primary users achieve bidirectional communication.…”

Spectral efficiency maximisation of full‐duplex enabled relaying SWIPT system with successive interference cancellation and maximal ratio combining

“…Additionally, some works have discussed relaying communication in SWIPT system [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. In [12], authors proposed a split-step iterative method and an alternate convex optimisation method for the joint time allocation (TA) and power splitting (PS) problem in the half-duplex (HD) decode-and-forward (DF) EH relaying network to minimise the outage probability and maximise the instantaneous channel capacity.…”

“…Authors proposed adaptive maximum ratio combining protocol to achieve better communication through choosing time switching mode and PS mode in [15]. Zhang et al [16] derived exact closed-form expressions of outage probability and achievable throughput of primary and secondary systems under the proposed dynamic timepower-based cooperative spectrum sharing protocol for the AF and DF relaying SWIPT system. Authors considered static and dynamic PS scheme to optimise the coverage performance and exploit the diversity gain of dual-hop DF relaying network in the presence of a direct link [17].…”

Resource Allocation in Cognitive Radio Wireless Sensor Networks with Energy Harvesting

“…Li et al [28] considered a spectrum-sharing scheme based on simultaneous wireless information and power transfer (SWIPT). Zhang et al [29] proposed a new cooperative spectrum-sharing protocol with dynamic time-slot allocation based on energy harvesting. However, none of the related works mentioned above takes into account resource allocation in CRWSNs with energy harvesting.…”