Energy Harvesting for TDS-OFDM in NOMA-Based Underwater Communication Systems

Area of Science:

• Underwater acoustic communication
• Wireless communication systems
• Signal processing

Background:

• Non-orthogonal multiple access (NOMA) offers high spectral efficiency, making it suitable for limited bandwidth underwater acoustic channels.
• Time-division synchronization OFDM (TDS-OFDM) is attractive for underwater multicarrier communication but suffers from wasted power in long guard intervals.
• Energy harvesting in battery-powered underwater systems is crucial but challenging due to the ocean environment.

Purpose of the Study:

• To propose a Time Switching Simultaneous Wireless Information and Power Transfer (TS-SWIPT) scheme for TDS-OFDM-NOMA systems.
• To harvest energy from wasted power in the guard interval of TDS-OFDM-NOMA.
• To enhance the energy efficiency of underwater acoustic communication.

Main Methods:

• Utilizing superposition coding (SC) at the NOMA transmitter.
• Employing successive interference cancellation (SIC) at the NOMA receiver.
• Implementing TS-SWIPT to harvest energy from the guard interval in TDS-OFDM-NOMA.

Main Results:

• The proposed scheme effectively harvests energy from the guard interval.
• Significant improvements in energy efficiency were demonstrated.
• Enhanced spectral efficiency, better bit error rate (BER) performance, and higher system data throughput were achieved.
• The superiority of the proposed TDS-OFDM-NOMA over the underwater acoustic channel was validated.

Conclusions:

• The proposed TS-SWIPT scheme successfully addresses the energy efficiency challenges of TDS-OFDM-NOMA in underwater acoustic environments.
• This approach offers a viable solution for extending the operational life of underwater communication systems.
• The integrated system demonstrates superior performance metrics, paving the way for more robust underwater networks.