Table 1.

Summary of architecture layer analysis.

Architecture layer	5 layers	4 layers	3 layers	Ratio
Application	Liu et al. (2018)	Xu et al. (2019); Din et al., 2018; Sengupta et al. (2019); IEEE, 2020	Noor and Hassan, 2019	19%
Cloud computing		Zhang et al. (2018); Din et al., 2018		6%
Cloud-to-end-fusion		Ma et al. (2017)		3%
Cloud service		Ma et al. (2017)		3%
Platform		IEEE, 2020		3%
Processing		Sengupta et al. (2019)		3%
Data integration	Liu et al. (2018)			3%
Edge computing		Zhang et al. (2018)		3%
Transport		Ma et al. (2017)		3%
Network	Liu et al. (2018)	Xu et al. (2019); Din et al., 2018; Sengupta et al. (2019)	Noor and Hassan, 2019	16%
Analysis		Xu et al. (2019)		3%
Base station		Zhang et al. (2018)		3%
Communication	Liu et al. (2018)	IEEE, 2020		6%
Perception		Ma et al. (2017); Sengupta et al. (2019)	Noor and Hassan, 2019	9%
Sensing	Liu et al. (2018)	Xu et al. (2019); Din et al., 2018; Zhang et al. (2018)		13%
Device		IEEE, 2020		3%