Cooperative Access Schemes for Efficient SWIPT Transmissions in Cognitive Radio Networks

TL;DR

This paper proposes and analyzes cooperative access schemes in cognitive radio networks where secondary nodes assist primary transmission and energy harvesting, improving data rates for both primary and secondary users.

Contribution

It introduces a three-stage cooperative protocol with five schemes, including distributed beamforming and relay selection, with analytical rate expressions and performance evaluation.

Findings

Proposed schemes enhance primary and secondary data rates.

Distributed beamforming improves primary power transfer.

Numerical results confirm the benefits of cooperation and energy harvesting.

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 relay-selection scheme based on the compressive sensing principles. Our numerical results demonstrate the gains of our proposed schemes for both the primary and secondary systems.