Table 5.

Summary of the relevant studies on multichannel PPG.

Configuration	Sensing Point	PD/LED	LED Power (mW)	References
Textile sleeve	Wrist	2/2 (1 red and 1 IR)	14.5 red, 6.8 IR	This study
Ear-worn platform	Ear	3/2 IR	2	Wang et al. [18]
Wrist watch	Wrist	4/4 IR	2	Lee et al. [19]
Elastic headband	Forehead	1/6 (3 red and 3 IR)	–	Mendelson et al. [20]
Electronic patch sensor	Forehead, wrist, head	1/16 (4 red, 4 IR, 4 green, 4 yellow)	–	Alzahrani et al. [21]