Low-PAPR Pulse Shaping for Single-Carrier FDMA

High Peak-to-Average Power Ratio (PAPR) is a critical limitation in Orthogonal Frequency Division Multiplexing (OFDM) systems, particularly in 5G and Internet of Things (IoT) applications where energy efficiency is essential. In Single-Carrier Frequency Division Multiple Access (SC-FDMA) uplink systems, suppressing sidelobes of the impulse response is vital to lowering PAPR and maintaining spectral efficiency. This paper introduces an enhanced pulse-shaping function, termed iPOWER+, derived from the conventional POWER pulse through a novel exponential formulation with two additional design parameters, ρ and γ, which enable fine control of sidelobe attenuation for a given roll-off factor α. The iPOWER+ pulse was evaluated against benchmark shapes including Raised-Cosine (RC), Exponential Raised-Cosine (ERC), Exponential Linear Pulse (ELP), and Piecewise Linear (PWL), as well as iPOWER+ configurations with β = 0, 1, 2, 3, 4, and 5, through extensive computer-based simulations and a LimeSDR-based RF testbed. Simulation results demonstrate up to 1.39 dB average PAPR reduction and a 5.5% improvement in Symbol Error Rate (SER) for iPOWER+ compared with benchmark pulses, while maintaining competitive Error Vector Magnitude (EVM) with a simulated gain of 0.1%. Hardware experiments confirm a consistent 9.6% EVM improvement under nonlinear RF conditions, demonstrating robustness to amplifier compression and non-idealities. Minor trade-offs in spectral efficiency and potential inter-symbol interference (ISI) at higher roll-off factors remain within acceptable limits without increasing computational complexity for β values up to 4. Overall, iPOWER+ provides a balanced, energy-efficient solution for next-generation SC-FDMA uplink systems, combining low PAPR, improved SER, and robustness under RF impairments.