Abstract:
Massive machine type communication (mMTC) has emerged as a key driver for societal
digitalization, promising connectivity to a vast number of devices, reaching up
to 10M/km2. However, conventional cellular systems struggle to efficiently handle the
massive influx of short packet transmissions inherent to mMTC. Non-Orthogonal Multiple
Access (NOMA) presents a promising solution by allowing multiple users to share
the same resources. This paper explores the integration of Power-Domain NOMA (PDNOMA)
and Sparse Code Multiple Access (SCMA) to superimpose extra users having
different quality of service requirements, on the SCMA multiplexed signal in a spectrally
efficient manner. The proposed hybrid system demonstrates increased spectral
efficiency, enhanced overloading capability, reduced receiver complexity as compared
to traditional NOMA and SCMA systems.
