The suggested method's main aim is to improve energy quality and extend the network's running time in the WCSN [7]. The Multi-driven Clustering Algorithm (MCA) for WCSN has been introduced in this section, which is based on the EDT (Energy, Distance and Time) Strategy. Cluster creation, CH (Cluster Head) collection, as well as replacement CH is all part of the cluster setup process. [8] Overall, the proposed approach is based on an EDT (Energy, Distance, Time) guided strategy that uses the Cluster Head Rotation Algorithm. Furthermore, the compressive sensing (CS) scheme has been combined with the clustering algorithm. [9] Energy efficiency decreases with Fs (Sampling Frequency) so Compressive Sensing method is used to prolong the overall working time. Once the Base Station (BS) gets the specification values such as n, ε, k, and s, It determines the best optimal solution for cluster at each layer according to the Eq. (1)
Eventually, CH choosing the best optimal solution according to the it layers of Cluster Head. Now the Base station reports all the optimal information about CH to all the participating nodes in broadcast form. When the BS transmits the information to participating SN it calculates the RE−D and it remembered. [11] Then the participating nodes send the (HELLO) packets which contain cluster ID and NRE−D (Node Residual Energy to distance). [12] The SN compare RE values with the collected message (HELLO) if the rate was smaller, it forwarded the HELLO packets to the neighbor node. Or else, it rejected the HELLO message and created the latest CH selection packet. In Fig. 1 given below, it shows the cluster head selection in WCSN.
Once completed the above steps, redo the steps till the clusters are joined with neighbor node. [13–14] Sometimes base station does not transmit HELLO packets to the sensor node, so it chosen itself as a secluded cluster head. After completing each round, CH compared with RE−Dif the residual energy value is smaller, then the present cluster head handover all responsibilities to the Substitute Cluster Head (SCH). In this way rotation conducts between CH and SCH. [16] Afterwards SCH collects the information from cluster head, it will be announced to the entire cluster member (CM). So, it went back to the next cluster formation phase.
3.1 CH Rotation Strategy
The sink flooded hello packet messages directly to all participating nodes based on this flow diagram. The Received Signal Strength Indicator (RSSI) will measure the SN distance from the base station after the HELLO message has been received. [20] Energy, Distance, and Time (EDT) driven strategy is one type of CH rotation strategy. The TDRE technique can be used to evaluate the WCSN network's energy use. In the other hand, determining the rotation time for each round is complicated. [21] There will be periodic Cluster Head rotation if the rotating time is short and there will be little effect on determining the energy consumption if the rotating time is long. Up to the minimum range, the effect of the TDRE loop may be monitored. [22–23] Data transmission would require less and less energy as the residual energy of the CHs was reduced. The CHs' energy would soon surpass the energy barrier, causing the entire network to crumble into a continuous choice of rotation, with only little sensitivity to transmitting energy [24]. As energy efficiency deteriorates, an effective energy gateway is needed to reduce energy usage as well as extend network life.
(Where, NRE = Node Residual Energy; B-NRE = Base Station to Node RE; RNRE = Required Node to RE; RNSd = require Node to Sink distance; RNSt = Required Node to Sink time; TDRE = Threshold Differential Residual Energy; TNSD = Threshold Node to Sink Distance; TNST = Threshold Node to Sink Time)
From the Fig. 2, If the actual NRE is higher than the B-NRE, then it will check TDRE for all nodes (Threshold Differential Residual Energy) if any cluster node has highest energy than the required node to RE, so it will take Substitute Cluster Head (SCH) as a CH and changeover the role of the CH to the substitutes (SCH). Then Data Deduplication (DD) process occur which can delete the extra copies of same data and send only one data to the particular sink, afterwards data transmission process occurs easily [25]. If the rate was smaller, it forwarded the HELLO packets to the neighbor node. Or else, it rejected the HELLO message and created the latest CH selection packet.
If all the participating node has same energy level (for example each node have1J difference) it is difficult to get a CH, so check TNSD (Threshold Node to Sink Distance) for all nodes, one of the cluster nodes is very nearest to the sink when compared with required node to sink distance. If the above condition is accepted, it eliminates the duplicate copies of same data and it consist only one copy which reduces the storage cost. After that Data transmission will occurs where SN transmits to the BS by "hop-by-hop” method.
The energy efficiency gradually reduces when the network’s durability is lower. At lower-state, TNST (Threshold Node to Sink Time) can achieve high energy efficiency. At initial stage, both TDRE and TNSD is used in some cases it doesn’t find the substitute CH; finally, it checks TNST for all nodes. If TNST is higher than node to sink time, t transmits ‘n’ rounds of data to the participating sensor nodes else it rejected the message and again created a new CH selection packet. The energy can be defined as
$$\text{e}= \frac{{{\epsilon }}_{\text{s}\text{t}\text{e}\text{a}\text{d}\text{y}}}{{{\epsilon }}_{\text{s}\text{t}\text{e}\text{a}\text{d}\text{y}}+{{\epsilon }}_{\text{s}\text{e}\text{t}\text{u}\text{p}}}$$
2
Where ‘e’ is Energy efficiency;\({\epsilon }_{steady}\) is used to sense and transmits the data; \({\epsilon }_{setup}\)is used to select the cluster head and for cluster formation. Let us consider there are n rounds of data transmission in TNST. Then the energy efficiency of TDRE is calculated by the Eq. (3)
$${\text{E}}_{\text{T}\text{D}\text{R}\text{E}}= \frac{\text{n} \left({{\epsilon }}_{\text{C}\text{H}}+{{\epsilon }}_{\text{C}\text{M}}\right)}{{{\epsilon }}_{\text{s}\text{e}\text{t}\text{u}\text{p}}+\text{n}\left({{\epsilon }}_{\text{C}\text{H}}+ {{\epsilon }}_{\text{C}\text{M}}\right)} ;{{\epsilon }}_{\text{s}\text{t}\text{e}\text{a}\text{d}\text{y}}=\text{n} \left({{\epsilon }}_{\text{C}\text{H}}+{{\epsilon }}_{\text{C}\text{M}}\right)$$
3
Where,\({\epsilon }_{CH}\)energy consumption of main CHs in each round data transmission,\({\epsilon }_{CM}\) is energy consumption of CMs and vice CHs in each round data transmission. In the TDRE technique, if the residual energy of the main CH goes below a threshold, the whole network will be rotated. The threshold is shown in formula \(\lambda =c.{R}_{{E}_{i}}\) where 0 < c < 1.
The energy efficiency of the TDRE is calculated by Eq.(3)\(\phi\) =\(\frac{\left(1-c\right){R}_{{E}_{i}}}{{\epsilon }_{CH}}\); where \(\phi\)is number of rounds of data transmission.If TDRE is not used, it is replaced by TNSD or TNST by the Eq. (4)
$$\frac{\text{n} \left({{\epsilon }}_{\text{C}\text{H}}+{{\epsilon }}_{\text{C}\text{M}}\right)}{{{\epsilon }}_{\text{s}\text{e}\text{t}\text{u}\text{p}}+\text{n} \left({{\epsilon }}_{\text{C}\text{H}}+ {{\epsilon }}_{\text{C}\text{M}}\right)}= \frac{ {\phi }\left({{\epsilon }}_{\text{C}\text{H}}+{{\epsilon }}_{\text{C}\text{M}}\right)}{{{\epsilon }}_{\text{s}\text{e}\text{t}\text{u}\text{p}}+\text{n} \left({{\epsilon }}_{\text{C}\text{H}}+ {{\epsilon }}_{\text{C}\text{M}}\right)}$$
4
When TNST (Threshold Node to Sink Time) is below required node to sink time, the system discarded all packets and goes to cluster setup phase is shown in the Fig. 3. After the cluster formation, the CH calculates the ratio of RE−D and remembered it very well. If actual participating sensor node residual energy is higher, this proposed method presented a new strategy is called EDT strategy (Energy, Distance, and Time). From this new strategy, if the present cluster head gets reduced its energy, so CH needed a backup so in this method, present CH will be changed by SCH (Substitute Cluster Head) based on EDT.
Pseudo code For Multi Drive Edit Strategy
sink broadcast opt_ CH & opt _CH dist to all sensor nodes
for each node SNi do
calculate RE−D
receives HELLO packets (C_id &N RE−D)
compare RE−D with HP (N RE−D)
while SNi, TDRE0
SNi receives HP (C_id &N RE−D)
end
end
if (NR > B-NR)
check for TDRE
if (TDRE > RNRE)
it will take substitute as CH
else if
it check with TNSD
if (TNSD > RNSd)
eliminate the duplicated copies
compute data transmission
end
end
end
end
else
check TNST for all nodes
if (TNST > RNSt)
data deduplication occurs before data transmission
end
end