This title slide introduces the topic of hierarchical routing protocols in wireless sensor networks, with a specific focus on PEGASIS. The subtitle welcomes viewers to an academic overview that highlights PEGASIS's role in enhancing energy efficiency.

Hierarchical Routing Protocols in WSN: PEGASIS

Welcome to this academic overview of hierarchical routing in wireless sensor networks, emphasizing the PEGASIS protocol for energy efficiency.

Wireless Sensor Networks (WSN) are composed of distributed sensor nodes that collect data and enable real-time monitoring across diverse environments. The slide highlights key challenges such as energy constraints, scalability, and routing efficiency, alongside applications in areas like environmental monitoring and healthcare systems.

Introduction to WSN

• Wireless Sensor Networks (WSN) consist of distributed sensor nodes for data collection.
• Sensor nodes enable real-time monitoring in various environments.
• Key challenges include energy constraints, scalability, and routing efficiency.
• Applications span environmental monitoring and healthcare systems.

Hierarchical routing organizes network nodes into clusters led by elected cluster heads (CHs), which perform data aggregation to minimize transmissions and reduce energy consumption through efficient routing. Unlike flat networks, it employs multi-level structures to enhance scalability and performance.

Hierarchical Routing Concepts

• Organizes nodes into clusters with elected leaders (CHs)
• CHs perform data aggregation to minimize transmissions
• Reduces energy consumption through efficient routing
• Features multi-level structures unlike flat networks

Flat routing floods data packets across the entire network, leading to excessive redundancy, high energy use, rapid battery depletion in sensor nodes, and poor scalability in large wireless sensor networks. In contrast, hierarchical routing organizes nodes into clusters for data aggregation at cluster heads, which reduces communication overhead, balances energy load, enhances scalability, and extends the overall network lifetime.

Advantages over Flat Routing

PEGASIS is a chain-based protocol designed for energy-efficient data gathering in wireless sensor networks (WSN), where nodes form a single chain to minimize transmission distances. A leader node aggregates the data and forwards it to the base station, offering improved energy efficiency over the LEACH protocol.

PEGASIS Overview

• PEGASIS: Chain-based protocol for energy-efficient data gathering in WSN
• Forms single chain of nodes to minimize transmission distances
• Leader node aggregates data and forwards to base station
• Improves energy efficiency compared to LEACH protocol

Source: Hierarchical Routing Protocols in WSN

The slide outlines a five-step algorithmic process for energy-efficient data aggregation in a sensor network. It begins with constructing a chain of nodes using a greedy method, selecting a random leader, aggregating data along the chain to the leader, transmitting the aggregated data to the base station, and rotating the leader for the next round to balance energy use.

Algorithmic Steps

Step 1: Construct Chain via Greedy Algorithm Form a chain connecting all sensor nodes using a greedy approach to minimize energy consumption. Step 2: Select Random Leader Node Choose a random node from the chain to act as the leader for data aggregation in this round. Step 3: Aggregate Data Along Chain Nodes pass and aggregate data sequentially along the chain towards the selected leader node. Step 4: Leader Transmits to Base Station The leader node sends the aggregated data directly to the base station. Step 5: Rotate Leader for Next Round Select a new leader for the subsequent round to distribute energy load evenly.

LEACH is a cluster-based protocol that randomly elects cluster heads for data aggregation and multi-hop communication to the base station, effectively balancing energy but struggling with uneven head distribution in large networks. In contrast, PEGASIS creates a single chain linking all nodes to a leader for data relay, bypassing clusters and elections to minimize transmission overhead, save more energy, and prolong network lifetime in expansive setups.

Comparison with LEACH

This slide outlines key advantages of the proposed protocol over LEACH, including a 40-50% reduction in energy dissipation and simplified routing by avoiding cluster formation overhead. It also highlights efficient handling of node failures via local repairs and scalability for dense network deployments.

Advantages

• Reduces energy dissipation by 40-50% compared to LEACH.
• Handles node failures through efficient local repairs.
• Scalable for deployment in dense networks.
• Simplifies routing by eliminating cluster formation overhead.

The slide outlines key limitations of a chain-based protocol, noting that long chains in large networks heighten latency. It also highlights risks like single points of failure at the leader node, unsuitability for sparse or mobile wireless sensor networks, and the need for global knowledge to build chains.

Limitations

• Long chains increase latency in large networks.
• Single point of failure at the leader node.
• Not ideal for very sparse or mobile WSNs.
• Requires global knowledge for chain construction.

PEGASIS advances hierarchical routing in wireless sensor networks (WSN) by optimizing energy efficiency through chaining, making it ideal for static and dense deployments. Future enhancements could focus on addressing mobility and latency challenges.

Conclusion

PEGASIS advances hierarchical routing in WSN by optimizing energy via chaining. Ideal for static, dense deployments. Future enhancements could address mobility and latency issues.

PEGASIS: Pioneering Energy Efficiency in WSN