Algorithm 1. Detection Period.

Input: $R_{req}$, ${\eta }_{\min }$, $T_{now}$, $\alpha$,$\beta$

Output: $\eta$

1.    $R(T_{now})=e^{-{(T_{now}/\alpha )}^{\beta }}$

2.    if $R(T_{now})>R_{req}$

3.      then $t_{req}=\alpha \cdot {(-\mathsf{l}{\mathsf{n}}^{R_{req}})}^{1/\beta }$;

4.        $\Delta t=t_{req}-T_{now}$;

5.        if $\Delta t>n\cdot {\eta }_{\min }$ (n>1)

6.          then $\eta =n\cdot {\eta }_{\min }$;

7.          else if ${\eta }_{\min }<\Delta t<n\cdot {\eta }_{\min }$

8.            then $\eta =\Delta t$;

9.            else

10.              $\eta ={\eta }_{\min }$;

11.            end if

12.         end if

13.      else

14.        $\eta ={\eta }_{\min }$;

15.   end if