OUTPUT STATES
Graphical
The graph shows the rise in the level of the dead nodes with the increase in the no. of rounds taking place.
The another one shows the frequently varying no. of advanced nodes produced corresponding to each round.
Node Address
The above addresses are two different portrayals of how the locations of node is represented in a grid size and after setting the field according to the probability. The grid values are for x and y coordinates respectively in a particular range and same for their corresponding addresses.
The above figure represents the plotting of the nodes where the circles are the normal nodes and the plus ones are the advanced nodes. The above graphs represent the particular location in the x*y field for a node to be addressed in the grid taken into consideration for calculating the cluster head.
The Leach operation is carried on in rounds, where each round begins with a set-up phase when the cluster is organized, followed by a steady-state phase where sensor nodes send data to the cluster heads which aggregates it and forwards the information to a base station. During the steady-state phase, spread spectrum modulation is used to prevent interference between nodes of neighboring clusters. During set-up, cluster heads randomly chose CDMA (code division multiple access) spreading codes for their clusters. While TDMA eliminates interference within each cluster, CDMA restricts interference between the nodes of different clusters in the network.
The LEACH protocol is a form of cluster-based routing. It forms clusters to minimize the energy dissipation. The operations of this protocol is divided into two phases: the setup phase and the steady-state phase. The steady phase is of longer duration to minimize the overhead.
The setup phase consists of the following steps:
- The sensor node chooses a random number between 0 and 1.
- If this chosen random number is less than the threshold T(n), the sensor node is a cluster-head (CH):
otherwise,
where P = percentage chance of becoming a cluster-head, r = current round, and G = set of nodes that have not been selected as a cluster-head in the last 1/P rounds.
- The cluster-head then advertises its selection.
- After advertisement, the other sensor nodes decide whether they want to be part of this cluster-head’s cluster or not, based on the signal strength of the advertisement.
- The cluster-head assigns a timetable to the sensor nodes of its cluster based on the TDMA approach. At the indicated time the nodes can send data to the cluster-head.
This protocol does not address the network partition due to the nodes’ failure. Another main point of concern is the selection of the cluster-head in each round. A sensor node becomes the cluster-head with only a certain probability; hence there are more chances that part of the network is left without a cluster-head, leading to inefficient routing.
Various versions of LEACH protocol had been proposed in the literature, and they are are discussed below.
E-LEACH: The Energy-Leach protocol is an improvement over the LEACH protocol. This protocol changes the cluster-head selection procedure. In the first round, a cluster-head is chosen. All the nodes have the same probability of being a cluster-head. After the first round, nodes’ energy is also considered in cluster-head selection. A node with high residual energy is chosen as a cluster-head. The cluster-head is the main focused point for communication in the network and hence its working life will affect the communication between the sensor nodes. This protocol selects the cluster-head with maximum remaining energy or maximum working capacity; this provides stability in the network.
TL-LEACH: Two-Level Leach sends data to the base station in two hops. The cluster-head collects data from the other nodes. It then sends the collected data to the base station through another cluster-head that lies in between it and base station.
M-LEACH: In the Multihop Leach protocol, data is relayed to the base station in multiple hops. This protocol addresses the problem of data transmission from the far clusters to the base station. The cluster-head sends the collected data to the base station through another cluster-head that lies in between it and the base station. Due to multi hop communication, a lot of energy is saved at the cluster-head node.
LEACH-C: The Centralized Leach protocol introduces the centralized cluster formation algorithm. During the setup phase, nodes send their remaining energy and location to the sink. After that the sink runs a centralized cluster formation algorithm and forms the clusters for that phase. In each round, new clusters are formed by the sink. This protocol distributes the cluster-heads throughout the network based on the nodes energy and location; hence it may produce better results.
VLEACH: This is a new version of the Leach protocol. In this new version of the protocol, a cluster will have the cluster-head as well as a vice-cluster-head (CH and vice-CH). The vice-cluster-head will take the authority of the cluster when the existing cluster-head dies. This concept saves the energy of the cluster’s members, which they use in data collection. Remember if the cluster-head dies, the collected information could not reach the sink and the result is energy wastage by the nodes. With the help of the vice-CH, the collected information can now reach the sink even if the CH dies.
This blog therefore is based upon the leach protocol in wireless sensor network which is referenced to track the movements of a node in the field. The advancement in this protocol gives rise to the cluster head election which is used in the types of application of generating the maximum possibility move places for a horse in the game of a chess. This is thus developed into Matlab which is the best suited for such applications.
This blog helps one to understand the concept of the leach protocol and game theory more clear. The wireless sensor networks is very wide topic and hereby is covered and applied correctly to make work with the formation of main output out of this project. The Energy dissipation models and criterion upto the Cluster head selection is helping us learn the condition of the protocol and learning to take the right decision of the movement with the right conditions being satisfied. This also teaches on about Octave environment for the Matlab project and enabling smooth process.
