Minimizing Bit-Error-Rate by Optimizing Power Amplifier’s Output Power in Wireless Links

This paper presents a comprehensive analysis of the impact of a generic power amplifier’s (PA’s) output power on the bit-error-rate (BER) in a transceiver employing a 4<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sup>quadrature amplitude modulation (QAM) scheme. The study highlights the dual effects of excessive and insufficient output power on system performance. On one hand, low output power reduces the signal-to-noise ratio (SNR) at the receiver, leading to increased BER. On the other hand, high output power pushes the PA into its nonlinear region, similarly degrading BER. A quantitative analysis is conducted to examine the combined influence of noise and nonlinearity on BER. From this analysis, the globally optimal PA output power that minimizes BER for a wireless system is derived. Theoretical insights are validated through system-level simulations, demonstrating the effectiveness and high accuracy of analytical expressions.