Reader Scheduling for Tag Population Estimation in Multicategory and Multireader RFID Systems

Algorithm 1

The coloring region division.

Input: Number of monitoring units: m; Number of colors: M≤m; The relationship matrix between units: X; Initialize the color of regions: Y [0: m−1]=−1; flag=0;

Output: One scheme of graph coloring Y;

  Function UNCOLLISION(int k)

   for each i ∈ [0, k−1) do

    if X[k][i] == 1∧Y [k] == Y [i] then

     return false;

    else

     return true;

  function GRAPHCOLOR(int t)

   p=0;

   if t>= m then

    flag=1;

   while!flag ∧ p<M do

     Y [t]=p;

     p=p+1;

     if UNCOLLISION(t) then

      GRAPHCOLOR(t+1);

   if t == 0 then

    return null;

  GRAPHCOLOR(0);