Wireless-Powered Communication Assisted by Two-Way Relay with Interference Alignment Underlaying Cognitive Radio Network

TL;DR

This paper proposes a novel interference management and resource allocation scheme for a wireless-powered cognitive radio network with two-way relaying, significantly reducing outage probability through optimized power splitting, beamforming, and interference alignment.

Contribution

It introduces a joint design framework for power splitting, beamforming, and interference alignment in a MIMO cognitive radio network with wireless power transfer and two-way relaying, which is novel.

Findings

Achieves over two orders of magnitude reduction in outage probability.

Provides closed-form expressions for power splitting and relay power control.

Demonstrates the effectiveness of interference alignment in secondary networks.

Abstract

This study investigates the outage performance of an under-laying wireless-powered secondary system that reuses the primary users (PU) spectrum in a multiple-input multiple-output (MIMO) cognitive radio (CR) network. Each secondary user (SU) harvests energy and receives information simultaneously by applying power splitting (PS) protocol. The communication between SUs is aided by a two-way (TW) decode and forward (DF) relay. We formulate a problem to design the PS ratios at SUs, the power control factor at the secondary relay, and beamforming matrices at all nodes to minimize the secondary network's outage probability. To address this problem, we propose a two-step solution. The first step establishes closedform expressions for the PS ratios at each SU and secondary relay's power control factor. Furthermore, in the second step, interference alignment (IA) is used to design proper precoding and decoding matrices for managing the interference between secondary and primary networks. We choose IA matrices based on the minimum mean square error (MMSE) iterative algorithm. The simulation results demonstrate a significant decrease in the outage probability for the proposed scheme compared to the benchmark schemes, with an average reduction of more than two orders of magnitude achieved.