Robustness-Based Transmission Strategy for Wireless-Powered Communication Networks

Algorithm 1

Improved -means++ algorithm.

Input: The number of clusters , the energy states of nodes ;

Output: HEC;

1: ;

2: Randomly select an observation as the center from ;

3: while the number of the centers is less than do

4:  Select an observation as the center from with the probability that increases with the distance from the nearest known center to the observation;

5: end while

6: ;

7: repeat

8:  ;

9:   for to do

10:   According to the observation with state , select the cluster by (14);

11:  end for

12: for to do

13:   Calculate the center of the cluster in (18);

14: end for

15: until;

16: return HEC.