An Adaptive Approach to Discriminate the Persistence of Faults in Wireless Sensor Networks

Algorithm 1

Fault detection.

(1)  // Each node executes the algorithm at discrete time 𝑘𝑇

(2)  Broadcast the sensor reading 𝑥_𝑖.

(3)  set timer 𝑇_out.

(4)  Obtain the sensed data of one-hop neighbors 𝑁(𝑣_𝑖).

(5)  if  𝑇_out=true  then

(6)   Declare unreported nodes as hard faulty and isolate the node.

(7)  𝐞𝐧𝐝𝐢𝐟

(8)  Determine {𝐸}, the set of one-hop neighbors report identical sensor measurement 𝑥.

(9)  if (𝑥_𝑖=𝑥 and |{𝐸}|<𝜃₁) or (𝑥_𝑖≠𝑥 and |{𝐸}|≥𝜃₁) then

(10)    𝐹_state𝑖← soft faulty.

(11)    The node enters to observation state.

(12)  else

(13)     𝐹_state𝑖← Fault-free.

(14)  𝐞𝐧𝐝𝐢𝐟

(15)  Broadcast the 𝐹_state𝑖.