| Yaşar Nuri Sevgen An Energy-Based Adaptive Modulation Framework for Bandwidth-Efficient Information Transmission |
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| Abstract. Efficient bandwidth utilization remains a critical challenge in modern communication systems operating under spectrum constraints. Conventional angle-modulation techniques typically rely on fixed parameters and heuristic bandwidth estimation rules, such as the Carson approximation, which may result in unnecessary spectral occupation. In this work, an energy-based adaptive modulation framework is proposed, where the modulation index is determined through a constraint-driven design approach. The effective bandwidth is defined using cumulative spectral energy, ensuring that only the spectral components contributing a specified fraction of the total signal energy are considered as occupied bandwidth. Within this framework, the modulation index is adaptively selected as the minimum value that satisfies a predefined output signal-to-noise ratio (SNR) requirement, thereby achieving bandwidth minimization while maintaining reliable transmission performance. This formulation enables a direct and physically meaningful relationship between spectral occupancy and signal quality, avoiding reliance on heuristic approximations. Numerical evaluations demonstrate that the proposed method consistently achieves narrower bandwidth compared to the classical Carson rule while preserving the required output SNR. The presented approach provides a systematic and flexible alternative to conventional bandwidth design methods and is well suited for adaptive and spectrum-aware communication systems operating under dynamic channel conditions. |
| Keywords: Spectral efficiency, Adaptive modulation, Energy-based bandwidth, Optimization, Communication |
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| DOI: https://doi.org/10.54381/itta2026.4.06 |