A Fuzzy Dropper for Proportional Loss Rate Differentiation under Wireless Network with a Multi-State Channel

Algorithm 1

The FPLR algorithm.

𝐿_𝑖: the number of lost packets of class i

𝐴_𝑖: the number of arrived packets of class i

𝜎_𝑖: the loss differentiation parameter of class i

𝐶(𝐻_𝑖): the channel capacity encountered when the scheduler transmits the HOL packet of class i

𝐵(𝑡): the set of backlogged classes at present t

𝑃𝑆_𝑖: the size of the HOL packet in class i

𝑃_𝑖,𝑓: the center of the membership function recommended by the consequence of rule f of class i

𝜇_𝑖,𝑓(𝑃_𝑖,𝑓): the degree of membership of input variables, packet size and

        channel states, of class i

𝑃_out𝑖: the defuzzified output of FCS of class i

𝜃: drop threshold

debt_𝑖: lost debt of class i

FPLR Dropper

{

 a class-i packet arrives at time t,𝐴_𝑖(𝑡)++;

 if (buffer overflow){

   calculate𝐿_𝑖(𝑡)=𝐿_𝑖(𝑡)/𝐴_𝑖(𝑡)𝜎_𝑖, 𝑖=1,2,…,𝑁;

   calculate𝑃_out𝑖=∑^𝑛_𝑓=1𝜇_𝑖,𝑓(𝑃_𝑖,𝑓)𝑃_𝑖,𝑓/∑^𝑛_𝑓=1𝜇_𝑖,𝑓(𝑃_𝑖,𝑓), i = 1, 2,…, N; f = 1, 2, 3, 4, 5;

  J=argmin_{𝑖∈𝐵(𝑡)}𝐿_𝑖(𝑡);

  debt_𝑖=0;

  if (𝐿_𝐽(𝑡)>(∑^𝑁_𝑖=1𝐿_𝑖(𝑡)/𝑁)) then debt_𝐽=−0.25, 𝑖=1,2,…,𝑁;

  else if (𝐿_𝐽(𝑡)<(∑^𝑁_𝑖=1𝐿_𝑖(𝑡)/𝑁)) then debt_𝐽=0.25, 𝑖=1,2,…,𝑁;

  if ((𝑃_out𝐽+debt_𝐽)> 𝜃) {

      drop the HOL packet from class J;

      𝐿_𝐽(𝑡)++;}

  else{

    do {

        find𝐾=argnextmin_{𝑖∈𝐵(𝑡)}𝐿_𝑖;

        if ((𝑃_out𝐾+debt_𝐾)> 𝜃) {

        drop the HOL packet from class K;

       𝐿_𝐾(𝑡)++;}

    } while(one packet is dropped or all classes have been visited)

    if (no packet is dropped){

      drop the HOL packet from class J;

      𝐿_𝐽(𝑡)++;}

    }

  accept the incoming packet;

}