LINEAR COMPANDING TRANSFORM FOR PAPR REDUCTION IN HIGH-PERFORMANCE OFDM COMMUNICATION SYSTEMS

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) forms the core infrastructure of modern high-speed wireless networks due to its exceptional spectral efficiency and superior resilience against multipath frequency-selective fading channels. However, the multi-carrier processing methodology exhibits an inherent technical limitation: a high Peak-to-Average Power Ratio (PAPR). High PAPR forces the radio-frequency power amplifiers to operate in their highly non-linear regions, introducing severe out-of-band spectral emissions and significant in-band signal degradation. This paper presents a detailed architectural framework and experimental analysis of the Linear Companding Transform (LCT) engineered to systematically mitigate PAPR constraints while preserving optimal Bit Error Rate (BER) performance profiles. By selectively compressing large signal peaks and expanding smaller dynamic range amplitudes through an optimized statistical model, the proposed LCT framework converts the standard Rayleigh-distributed signal profiles into a controlled uniform probability density layout. The exhaustive simulation metrics evaluate the system across distinct transform parameters using Complementary Cumulative Distribution Function (CCDF) benchmarks and BER trajectories under realistic Additive White Gaussian Noise (AWGN) and multi-path fading environments. The empirical results demonstrate that LCT delivers a substantial 4.8 dB reduction in PAPR thresholds while maintaining strict compliance with signal constellation distortion tolerances, offering an optimized implementation path for power-constrained multi-carrier wireless architectures.