LEACH and TEENfollow self-organizing and adaptive CH selection criteria. In setup phase, CH is elected on the bases of following threshold equation1 [32]; Fig.3 and Fig.4.
T(n)={■(p/(1-p(rmod 1/p) )&ifn∈G@0&otherwise)┤ (1) wherep is the desired number of CHs, r is the current round and G is the set of nodes that have not been CH in the current epoch. Epoch is the number of rounds for a CH, after which again it become eligible to become a CH. Each node generates a random number between 0 and 1, if the number is less than the node’s threshold, then this sensor node becomes a CH. After the election of CHs, each CH advertises its status using CSMA MAC protocol. Node selects its CH, on the bases of RSSI and link quality …show more content…
DEEC Protocol
DEEC [32-35] is another enhancement of LEACH for multi-level heterogeneous environment with respect to level of energies in WSNs. In SEP, energy distribution for two levels, advance nodes and normal nodes, whereas, DEEC introduces multi-level heterogeneity for maximizing K. The nodes having greater residual energy have more right to become a CH. Therefore, CH formation in DEEC is based on residual energy of entire network and residual energy of the node that wants to become a CH. SEP calculates optimum number of CHs from equation 4 and 6 for advance and normal nodes, respectively. While, in DEEC, for multilevel heterogeneous node energy environment, nodes with higher residual energy attains more chances to become a CH, Fig.6. Therefore, DEEC calculate optimum number of CHs for each round from the two …show more content…
To evade that each node needs to have the global knowledge of the networks, DDEEC like DEEC estimate the ideal value of network lifetime, which is used to compute the reference energy that each node should expend during each round. In the scheme, the network is organized into a clustering hierarchy, and the cluster heads collect measurements information from cluster nodes and transmit the aggregated data to the base station directly. Moreover, the authors have supposed that the network topology is fixed and no-varying on time, Fig.7. The difference between DDEEC and DEEC is localized in the expression which define the probability to be a cluster head for normal and advanced nodes. Simulation results show that the protocol performs better than the SEP and DEEC in terms of network lifetime and first node