Algorithm 2 WSN parameter calculation. Service time

Input: Circular matrix of service time measures $serv\_measure$

Array $number\_cpo\left[256\right]$ of CPO to be executed

Output: Medium service time $\overrightarrow{\mu }$

Obtain the current date in Epoch format, create a variable $initial\_date$

Create an integer $pending\_op$ equal to one

while$pending\_op$ is higher than zero then

$pending\_op$ is equal to the addition of elements in $number\_cpo$

Wait for the result of an operation

Subtract one unit to $number\_cpo\left[\left(int\right)result.CPO\_ID\right]$

if received result is not a cancellation then

Obtain the current date $current\_date$ in Epoch format

Store the new measure $current\_date – initial\_date$ in $serv\_measure$ in the row $\left(int\right)result.CPO\_ID$

end if

end while

for each server group ${\mathcal{S}}_i$ do

Integer $num\_measure$ is equal to number of non-zero elements in i-th row of $serv\_measure$

$Acc\_time$ is equal to the addition of all non-zero elements in i-th row of $serv\_measure$

${\mu }_i= Acc\_time /num\_measure$

end for