* prior to data communication, control packets are transmitted by nodes to VCH for authentication.
* all control messages are processed one at a time by VCH in the order in which they occur.
Among the set of nodes, the node with highest score is considered for VCH selection candidate and is elected as VCH i.e., if a node 'n;' has greatest score in its neighborhood, it declares itself a Virtual Cluster Head.
Step 5: Node '[n.sub.i]' declares itself as a VCH by propagating "VC Formation" message to its neighbors.
VCH rotation is triggered after every '[t.sub.i]' time slot ( where '[t.sub.i]' depends specific to application), ie., after '[t.sub.i]' time slot if node '[n.sub.i]' is found inappropriate (by comparing updated scores of nodes) to act as a VCH, it sends a "VCH Message" to node '[n.sub.r]' (node with highest score) to become a VCH and waits for a fixed duration of time '[delta]' to receive a response back from the node '[n.sub.r]'.
VC[H.sub.node] = Nod[e.sub.i]; VC[H.sub.node] [right arrow] VCH_fmsg; // VCH propagates cluster formation message to neighbors Nod[e.sub.neighbor] [left arrow] VCH_fmsg; // Neighbors receives VCH message and becomes part of cluster Nod[e.sub.neighbor] [right arrow] VCfrm_msg; // Neighbors send confirmation message to VC[H.sub.node] Algorithm 2.
Select three nodes from S(c) for which maximum weights are obtained in WO, to act as CH, VCH, and V-VCH, respectively.
Upon receiving this, each node compares its ID with the IDs of CH, VCH, and V-VCH to know its responsibility in the cluster.
(2) If VCH or V-VCH, then the node goes into the sleeping mode.
(3) If the node is not CH or VCH or V-VCH, then it fetches the ID of the corresponding CH along with the TDMA slot.
Each CH checks its residual energy after every communication round, and if it is less than or equal to ten percent of initial energy (when handed the responsibility of the CH) it awakens the corresponding VCH. It then transfers its current state to the VCH such as IDs of all CMs and neighbor(s) information along the CH chain.
The VCH becomes the new CH, creates the new TDMA for the cluster, and broadcasts it to the CMs.