Boundary Detection Method for Large-Scale Coverage Holes in Wireless Sensor Network Based on Minimum Critical Threshold Constraint

Algorithm 1

Local large-scale coarse boundary detection algorithm.

Input: Global coarse boundary , network graph inside , the ID set

   of all the sensor nodes in , the minimum critical threshold of large-scale coverage hole .

Output: Local large-scale coarse boundary .

(1)    while    do

(2)   for each sensor node   do //parallel process

(3)  generating a random time remaining;

(4)  if   == 0 do

(5)   generating a directed shortest path tree ;

(6)   ;

(7)   broadcasting the ID of and its initial random time remaining ;

(8)  end

(9)  if sensor node receives the ID sent by sensor node   do

(10)   if   doesn’t belong to any directed shortest path tree do

(11)    ;

(12)    ;

(13)   else

(14)    if    do

(15)      all node IDs in ;

(16)     broadcasting the ID of and its initial random time remaining ;

(17)    end if

(18)   end if

(19)  end if

(20) end for

(21)  end while

(22)  ← the cut node pair set in the directed shortest path tree ;

(23)  for each cut node pair in   do

(24) ← Tarjan ();//Tarjan is a offline least common ancestor algorithm

(25) ← computing the sum for path between to and to ;

(26)  end for

(27)  ← finding the cut node pair corresponding with the minimum value in ;

(28)  ← Tarjan ();

(29)  ← the shortest path between to ;

(30)  ← the shortest path between to ;

(31)  ← Min(, );

(32)  ← Min;

(33)  if    do

(34)  ;

(35)  end if

(36)  return  ;