Power Amplifier-Aware Transmit Power Optimization for OFDM and SC-FDMA Systems

TL;DR

This paper introduces a power amplifier-aware transmit power optimization method for OFDM and SC-FDMA systems, enhancing signal quality by modeling nonlinear PA effects and maximizing SNDR, with SC-FDMA showing superior performance.

Contribution

It presents novel analytical and semi-analytical models for SNDR optimization considering nonlinear power amplifier effects in OFDM and SC-FDMA systems.

Findings

Optimized transmit power improves receiver signal quality.

SC-FDMA outperforms OFDM in SNDR after optimization.

Power amplifier-aware optimization enhances next-generation wireless system performance.

Abstract

The Single Carrier-Frequency Division Multiple Access (SC-FDMA) is a transmission technique used in the uplink of Long Term Evolution (LTE) and 5G systems, as it is characterized by reduced transmitted signal envelope fluctuations in comparison to Orthogonal Frequency Division Multiplexing (OFDM) technique used in the downlink. This allows for higher energy efficiency of User Equipments (UEs) while maintaining sufficient signal quality, measured by Error Vector Magnitude (EVM), at the transmitter. This paper proposes to model a nonlinear Power Amplifier (PA) influence while optimizing the transmit power in order to maximize the Signal to Noise and Distortion power Ratio (SNDR) at the receiver, removing the transmitter-based EVM constraint. An analytic model of SNDR for the OFDM system and a semi-analytical model for the SC-FDMA system are provided. Numerical investigations show that the proposed transmit power optimization allows for improved signal quality at the receiver for both OFDM and SC-FDMA systems. However, SC-FDMA still outperforms OFDM in this matter. Such a power amplifier-aware wireless transmitter optimization should be considered to boost the performance and sustainability of next-generation wireless systems, including Internet of Things (IoT) ones.