  Next-generation wireless networks require higher spectral efficiency and
lower latency to meet the demands of various upcoming applications. Recently,
non-orthogonal multiple access (NOMA) schemes are introduced in the literature
for 5G and beyond. Various forms of NOMA are considered like power domain, code
domain, pattern division multiple access, etc. to enhance the spectral
efficiency of wireless networks. In this chapter, we introduce the code
domain-based sparse code multiple access (SCMA) NOMA scheme to enhance the
spectral efficiency of a wireless network. The design and detection of an SCMA
system are analyzed in this chapter. Also, the method for codebooks design and
its impact on system performance are highlighted. A hybrid multiple access
scheme is also introduced using both code-domain and power-domain NOMA.
Furthermore, simulation results are included to show the impact of various SCMA
system parameters.ext-generation wireless networks require higher spectral
efficiency and lower latency to meet the demands of various upcoming
applications. Recently, non-orthogonal multiple access (NOMA) schemes are
introduced in the literature for 5G and beyond. Various forms of NOMA are
considered like power domain, code domain, pattern division multiple access,
etc. to enhance the spectral efficiency of wireless networks. In this chapter,
we introduce the code domainbased sparse code multiple access (SCMA) NOMA
scheme to enhance the spectral efficiency of a wireless network. The design and
detection of an SCMA system are analyzed in this chapter. Also, the method for
codebooks design and its impact on system performance are highlighted. A hybrid
multiple access scheme is also introduced using both code-domain and
power-domain NOMA. Furthermore, simulation results are included to show the
impact of various SCMA system parameters.
