An Energy-Aware Retransmission Approach in SWIPT-Based Cognitive Relay Systems

Area of Science:

• Wireless Communication
• Cognitive Radio
• Signal Processing

Background:

• Spectrum sharing between primary users (PU) and secondary users (SU) is crucial for efficient wireless resource utilization.
• Simultaneous Wireless Information and Power Transfer (SWIPT) offers a promising approach for energy harvesting in wireless networks.
• Cognitive relays can enhance system performance by intelligently managing shared spectrum resources.

Purpose of the Study:

• To investigate cooperative spectrum sharing between a PU and an SU using a cognitive relay with SWIPT capabilities.
• To propose and analyze an Energy-Aware Retransmission (EAR) scheme to optimize energy harvesting and system reliability.
• To evaluate the outage and throughput performance for both PU and SU under the proposed framework.

Main Methods:

• A two-phase relaying model is employed, where the secondary transmitter (ST) splits power for energy harvesting and signal processing.
• The ST utilizes harvested energy to amplify-and-forward a weighted combination of PU and SU signals.
• The EAR scheme ensures a minimum energy threshold is met before signal retransmission.

Main Results:

• Theoretical analysis of outage and throughput performance for both PU and SU is presented.
• Simulation results confirm a mutually beneficial relationship between PU and SU under optimal parameter settings.
• The EAR scheme demonstrates significant performance gains in challenging scenarios, such as high data rates and low transmission power.

Conclusions:

• Cooperative spectrum sharing with SWIPT and a cognitive relay is feasible and beneficial for both primary and secondary users.
• The proposed EAR scheme effectively enhances system reliability and performance, particularly in adverse wireless conditions.
• This approach offers a 'win-win' solution for spectrum utilization and energy management in cognitive radio networks.