Procedure ACO Based Routing and Clustering in WMSNs

1. Initialization

Initialize the pheromone of lines between all sensor nodes, τij (i, j = 1,2,…, n)

Initialize the ant colony which contains k groups of ants. And each group consists of m ants.

Repeat

2. Assign the number of sensor nodes to every ants

For each group i∈[1,…,k] and each ant j∈[1,…,m]:

Randomly select a sensor node as starting sensor nodes for current ant.

Randomly assign a number of sensor nodes, $n_j^i$, to jth ant in ith group.

Endfor

3. Route Selection

For each group i∈[1,…,k] and each ant j∈[1,…,m]:

If the number of sensor nodes in sub-tour list $H_j^i$ is less than $n_j^i$

Then generate the probability of potential routes by Eq. (29) and select the next sensor node

Else current ant returns to its starting sensor node

EndIf

Endfor

4. Pheromone Updating

For each group i∈[1,…,k]:

Calculate the total distance, $D_i^{*}$, accessed by current group of ants.

Endfor

Find the optimal group of ants with the smallest $D_i^{*}$

Update the pheromone by Eq. (32) and Eq. (33)

Until stopping condition is satisfied (usually when the number of iterations reaches a predefined threshold, or when the best solution does not update for a certain number of iterations.)

5. Output results

Output the routing and clustering results indicated by current best solution