## 3 Proposed Solution
### EARMCDA: Energy Aware Routing Strategy (EAR) for Multilayer Cluster Designing Algorithm  
In the proposed Energy Aware Routing Strategy scheme, the status of a node is switched between different roles due to the rotation of \"Forwarding Node\" designation during the inter-cluster routing process. This is performed to save the network from partitioning and to prolong the network lifetime. In a sensor network, strategies which utilize to the maximum network nodes (also called network utilization) with maximum delay in the death of the first node are appreciated. This shows balanced behavior of the algorithm over network nodes and less danger of creating a void due to network partitioning as well. Rotation of CH designation is one of the initial steps towards it. The roles of  
Figure 2: Switching of a CH to different roles based on its energy threshold levels. switching in the four various designations are Decision Maker Node (\(DM_{Node}\)), \(FN\), \(BFN\) and Non- Forwarding Node (\(NFN\)). The subsequent paragraphs briefly explain these roles:  
3.3.1. Decision Maker Node  
The first elected FN by the CH is always from the list of \(DM_{Node}\) and satisfies the following condition:  
\(DM_{Node}\to FN=Cntr_{n(i)}>Cntr_{n(j)}\)\(\forall_{j}\) and \(\left|D(N_{i}\ -\ N_{j})\ \right|\ \leq r_{i}\)\(\forall_{j}\)\(Where\)\(j=1\),\(2\),..., \(n\)  
_i.e._, the node having highest neighbor count, \(Cntr_{n(i)}\) among its competitors (nodes in its communication range, \(r_{i}\)) is promoted from \(DM_{Node}\) to FN, while \(DM_{Node}\) are selected from FNS listed at CH of layer 2. 3.3.2. Forwarding Node  
The node that is elected to pass on the received packet toward the BS is called forwarding node. Nodes with any of the roles from among BFN, NFN or \(DM_{Node}\) can be upgraded to FN after winning some defined competition at various levels of operation. _Case I_: \(DM_{Node}\to FN\)  
_Case II_: \(BFN\to FN\)  
_Case III_: \(NFN\to BFN\to FN\)  
3.3.3. Backup Forwarding Node  
This node shares the FN load when its energy reaches the LBT threshold. The BFN is later upgraded to FN once its accompanying FN is degraded to NFN. To start, the node which satisfies the following condition is selected as BFN:  
\(BFN\to FN=E(N_{i})>E\big{(}N_{j}\big{)}\)\(\forall_{j}\) and \(\left|D(N_{i}\ -\ N_{j})\ \right|\ \leq r_{i}\)\(\forall_{j}\)\(Where\)\(j=1\),\(2\),..., \(n\)  
_i.e._, nodes having highest energy among their competitors are promoted from BFN to FN. Promotion of NFN to BFN follows a similar energy priority rule. 3.3.4. Non-Forwarding Node  
The \(DM_{Node}\) which has once acted as FN and finished its turn of being FN is termed as NFN. Also the node which is neither a FN nor BFN or \(DM_{Node}\) is given the name of NFN. The promotion of NFN to BFN only arises when CH does not have any \(DM_{Node}\) unelected as FN in its FN list. NFN is upgraded to BFN and later to FN on reaching the specified condition:  
\(NFN\to BFN\to FN\)  
Step 1:  
\(NFN\to BFN=E(N_{i})>E\big{(}N_{j}\big{)}\)\(\forall_{j}\) and \(\left|D(N_{i}\ -\ N_{j})\ \right|\ \leq r_{i}\)\(\forall_{j}\)\(Where\)\(j=1\),\(2\),..., \(n\)  
_i.e._, the node having the highest energy among its competitors is promoted from NFN to BFN. Step 2:  
\[BFN\to FN=E(N_{i})>E\big{(}N_{j}\big{)}\,\forall_{j}\,\,and\,\big{|}D(N_{i}\,-\,N_{j _{j}})\bigm{|}\leq r_{i}\,\forall_{j}\,\,Where\,j=1,2,...,n\]  
_i.e._, the node having the highest energy among its competitors is promoted from BFN to FN. Figure 3 summarizes these roles, their rotation and a brief description of their selection criteria. In view of above discussion, we can briefly summarize the working of EAR as follows: cluster member nodes communicate their collected data to the cluster head. Like all other nodes of the underlying layer, the CH under discussion also has a forwarding node table that has the node IDs of its decision maker nodes (\(DM_{Node}\)) in the preceeding level of their node degree. Nodes at the top in the list are selected as the forwarding node (FN).