Bringing Clarity to Composite Fading: A λ- κ-μ Shadowed Distribution for Complex Wireless Channels

Composite fading distributions provide tractable modeling of shadowing and multipath effects, enabling accurate channel characterization and improving communication reliability. Motivated by this, we propose λ-κ-μ shadowed distribution to precisely describe the signal fading behavior caused by the joint impact of shadowing effects and multipath clusters in non-homogeneous channels. Specifically, deterministic expressions for the probability density function, cumulative distribution function, and high-order raw moments are derived, immediately followed by key performance metrics, such as average bit error rate, ergodic capacity, and effective rate. Subsequently, asymptotic analyses of these metrics are conducted in the high signal-to-noise ratio regime to derive simplified expressions that facilitate system evaluation. Furthermore, we systematically analyze the relationship between these expressions and their parameters. The results demonstrate that our proposed λ-κ-μ shadowed distribution possesses good mathematical tractability, with its accuracy validated by Monte Carlo simulations. Additionally, we conduct the truncation error analysis to examine the convergence of the proposed model, and its practical applicability was confirmed through field measurements. More importantly, our proposed λ-κ-μ shadowed distribution subsumes multiple classical distributions as special cases, exhibiting strong flexibility and applicability.