• Seema H Paliwal
• Gajanan Pakhare
• Archana Nandkishor Shewale
• Rohan Pardeshi
• Amrita singh,Komal Wankhede

Abstract— The transition from fifth-generation (5G) to sixth-generation (6G) wireless networks is driving a fundamental rethink of physical-layer modulation and waveform design. While orthogonal frequency division multiplexing (OFDM) remains the workhorse of 4G and 5G New Radio, its sensitivity to high-mobility, doubly dispersive channels and its high peak-to-average power ratio (PAPR) limit its suitability for emerging 6G use cases such as terahertz (THz) communication, integrated sensing and communication (ISAC), and ultra-high-mobility non-terrestrial networks. This paper presents a comprehensive survey of modulation and waveform techniques spanning 5G and 6G systems. We review multicarrier alternatives to OFDM including filter bank multicarrier (FBMC), universal filtered multicarrier (UFMC), and generalized frequency division multiplexing (GFDM) before examining the delay-Doppler domain paradigm introduced by orthogonal time frequency space (OTFS) modulation and its index-modulation extensions. We further discuss the recently proposed affine frequency division multiplexing (AFDM) waveform, which uses chirp-based signalling in the discrete affine Fourier domain to achieve full diversity in doubly dispersive channels. Index modulation, non-orthogonal multiple access (NOMA)-aided modulation, and AI/ML-assisted waveform design are reviewed as cross-cutting enablers of spectral and energy efficiency. A comparative analysis of spectral efficiency, PAPR, complexity, and Doppler resilience is provided, followed by a discussion of open research challenges including receiver complexity, channel estimation overhead, and standardization and future directions for 6G modulation design.

5G, 6G, modulation, OFDM, FBMC, GFDM, UFMC, OTFS, AFDM, index modulation, NOMA, waveform design, ISAC.

"A Comprehensive Survey on Modulation Techniques for 5G and 6G Wireless Networks: From OFDM to OTFS and AFDM", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.13, Issue 9, page no.c174-c178, September-2026, Available :http://www.jetir.org/papers/JETIR2609220.pdf

"A Comprehensive Survey on Modulation Techniques for 5G and 6G Wireless Networks: From OFDM to OTFS and AFDM", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.13, Issue 9, page no. ppc174-c178, September-2026, Available at : http://www.jetir.org/papers/JETIR2609220.pdf