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Efficiency Maximization for Battery-Powered OFDM Transmitter via Amplifier Operating Point Adjustment
1Institute of Radiocommunications, Poznan University of Technology, 61-131 Poznan, Poland.
Sensors (Basel, Switzerland)
|January 8, 2023
Summary
Optimizing the Input Back-Off (IBO) for Orthogonal Frequency Division Multiplexing (OFDM) transmitters is crucial for balancing spectral and energy efficiency. This study explores various models to find optimal IBO values for 5G and beyond networks.
Area of Science:
- Electrical Engineering
- Wireless Communications
- Signal Processing
Background:
- Orthogonal Frequency Division Multiplexing (OFDM) is a key technology in wideband networks.
- Nonlinear components like Power Amplifiers (PAs) in radio front-ends introduce distortion, impacting signal quality.
- Optimizing PA operating points (Input Back-Off, IBO) is essential for transmission efficiency.
Purpose of the Study:
- To derive mathematical expressions for Energy Efficiency (EE) and Spectral Efficiency (SE) of OFDM transmitters.
- To analyze the impact of PA nonlinearity models (Rapp, soft-limiter) and power consumption models (Class A, B, perfect) on EE and SE.
- To incorporate battery models (perfect, worst-case) into the efficiency analysis.
Main Methods:
- Mathematical derivation of EE and SE expressions for OFDM transmitters.
- Inclusion of PA nonlinearity, power consumption, and battery models.
- Utilization of numerical methods to determine optimal IBO values and Signal-to-Noise and Distortion Ratios (SNDRs).
Main Results:
- Optimal IBO values were determined for various combinations of PA nonlinearity, power consumption, and battery models.
- Numerical results provided insights into achievable SNDRs.
- Significant variations in optimal IBO were observed based on wireless channel properties, hardware, and optimization goals.
Conclusions:
- The optimal IBO is highly dependent on system parameters and the chosen efficiency metric (SE vs. EE).
- Accurate modeling of PA nonlinearity, power consumption, and battery is critical for maximizing transmitter efficiency.
- The proposed optimization framework is vital for the design of efficient 5G and future wireless transmitters.
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