A Framework for Human Activity Recognition Based on WiFi CSI Signal Enhancement

Algorithm 2

N-iteration signal enhancement.

	Input: Sij—the sequential data of i-th subcarrier and j-th antenna for CSI signal
	W—the size of sliding window
	P—the number of iterations
	step—the step size of window movement
	Output: SEij—the enhanced sequential data of i-th subcarrier and j-th antenna
	Step 1: S = Sij
	Step 2: for (m = 0; m < P; m++)
	Step 3: N = the length of S
	Step 4: for (k = 0; k + W ≤ N; k = k + step)
	Step 5: ST = Ø
	Step 6: calculate the variance () of sequential data in sliding window from S
	Step 7: append to ST
	Step 8: end
	Step 9: S = ST
	Step 10: end
	Step 11: SEij = S
	Step 12: return SEij