Localization for Wireless Sensor Networks Assisted by Two Mobile Anchors with Improved Grey Wolf Optimizer

Table 2

Symbol list.

Symbol	Meaning
	-th unknown node
	Number of unknown nodes
	Two mobile anchors
	Actual position of
,	Estimated position of
	Path-loss exponent
	Variance of fading effect
	Radio radius of sensor nodes
	Degree of irregularity
	Position of -th virtual anchor
	Localization rate
	Average localization error
	Root mean square error of localization error
	RMSE of localization error variance
	Energy consumption for the mobile anchor to broadcast a beacon
	Energy consumption for the mobile anchor to move a meter
	Number of iterations of MDS-GWO
	Distance between two neighboring virtual anchors horizontally