Maximizing Reliability in Overlay Radio Networks with Time Switching and Power Splitting Energy Harvesting

2025-07-09

AI Summary

This paper addresses the joint optimization of energy efficiency (EE) and system reliability in cognitive radio networks (CRNs), where primary and secondary users coexist under overlay access. Method: We propose a unified EE optimization framework integrating time switching (TS) and power allocation, operating over κ-μ fading channels. The framework jointly exploits multi-antenna MIMO, maximum-ratio combining (MRC), amplify-and-forward (AF) relaying, and power splitting (PS) to enable simultaneous wireless information and power transfer. Contribution/Results: To the best of our knowledge, this is the first work achieving bidirectional EE enhancement for both primary and secondary users while satisfying strict outage probability constraints. Based on exact outage probability analysis, the optimization maximizes the secondary user’s data rate and overall network EE. Simulation results demonstrate that the proposed scheme significantly outperforms conventional approaches, effectively balancing energy harvesting and information transmission resource allocation without compromising communication reliability.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Combinatorial Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Security and Privacy: Applications of cryptography

Abstract

Cognitive radio networks (CRNs) are acknowledged for their ability to tackle the issue of spectrum under-utilization. In the realm of CRNs, this paper investigates the energy efficiency issue and addresses the critical challenge of optimizing system reliability for overlay CRN access mode. Randomly dispersed secondary users (SUs) serving as relays for primary users (PUs) are considered, in which one of these relays is designated to harvest energy through the time switching-energy harvesting (EH) protocol. Moreover, this relay amplifies-and-forwards (AF) the PU's messages and broadcasts them along with its own across cascaded $κ$-$μ$ fading channels. The power splitting protocol is another EH approach utilized by the SU and PU receivers to enhance the amount of energy in their storage devices. In addition, the SU transmitters and the SU receiver are deployed with multiple antennas for reception and apply the maximal ratio combining approach. The outage probability is utilized to assess both networks' reliability. Then, an energy efficiency evaluation is performed to determine the effectiveness of EH on the system. Finally, an optimization problem is provided with the goal of maximizing the data rate of the SUs by optimizing the time switching and the power allocation parameters of the SU relay.

Problem

• Optimize system reliability in overlay cognitive radio networks
• Enhance energy efficiency using time switching and power splitting
• Maximize secondary users' data rate via parameter optimization

Innovation

• Time switching-energy harvesting protocol for relays
• Power splitting protocol for energy storage enhancement
• Maximal ratio combining with multiple antennas