434  WSN Routing Fundamentals

434.1 Learning Objectives

By the end of this chapter series, you will be able to:

  • Understand WSN Routing Challenges: Identify why traditional routing protocols fail in sensor networks
  • Compare Routing Paradigms: Distinguish data-centric, hierarchical, geographic, and QoS-aware routing approaches
  • Evaluate Protocol Trade-offs: Analyze when to use proactive vs reactive routing
  • Apply LEACH Clustering: Understand how cluster head rotation balances energy consumption

434.2 Prerequisites

Before diving into this chapter, you should be familiar with:

  • Wireless Sensor Networks: Understanding WSN architecture, multi-hop communication, and energy constraints provides the foundation for specialized routing protocols
  • WSN Overview: Fundamentals: Knowledge of sensor network characteristics, data aggregation, and network topologies is essential for understanding routing decisions
  • Routing Fundamentals: Familiarity with basic routing concepts, routing tables, and forwarding mechanisms helps distinguish WSN-specific routing approaches
  • Multi-Hop Ad Hoc: Fundamentals: Understanding self-organizing networks and dynamic routing provides context for data-centric and geographic routing strategies
TipMVU: Minimum Viable Understanding

Core concept: WSN routing differs fundamentally from traditional network routing because it prioritizes energy efficiency over throughput and uses data-centric approaches instead of address-based routing.

Why it matters: Sensors operate on limited batteries for years; inefficient routing drains nodes prematurely, creating coverage gaps. Traditional shortest-path routing fails because it ignores link quality, energy levels, and the many-to-one traffic pattern in sensor networks.

Key takeaway: Choose routing protocols based on your application: Directed Diffusion for event-driven data collection, LEACH for hierarchical aggregation, geographic routing when GPS is available, and always consider link quality metrics (ETX) over simple hop count.

NoteKey Concepts
  • Routing Protocol: Algorithm determining paths for data packets to travel from source sensors to destination sinks through multi-hop networks
  • Energy-Aware Routing: Protocols that select paths based on node energy levels to balance consumption and extend network lifetime
  • Data-Centric Routing: Routing based on data content rather than node addresses, enabling in-network aggregation and filtering
  • Hierarchical Routing: Organizing network into clusters with cluster heads aggregating data from members before forwarding to sinks
  • Geographic Routing: Protocols using node location information to make forwarding decisions without maintaining routing tables
  • Quality of Service (QoS): Meeting application requirements for delivery reliability, latency, and bandwidth in routing decisions

434.3 Chapter Overview

This chapter has been organized into focused sections for easier learning. Work through them in order, or jump to the topic most relevant to your current needs:

434.3.1 1. WSN Routing Introduction

Fundamental concepts and why WSN routing is unique

Routing in Wireless Sensor Networks differs fundamentally from traditional network routing. This section introduces the core concepts, explains data-centric vs address-centric approaches, and provides beginner-friendly explanations.

  • Why WSN routing is different from traditional routing
  • Data-centric vs address-centric approaches
  • Energy-aware routing fundamentals
  • Protocol selection decision tree

434.3.2 2. WSN Routing Challenges

Why traditional routing fails in sensor networks

Traditional routing protocols like OSPF and BGP fail in WSNs due to energy constraints, scale, and communication patterns. This section explains the specific challenges and routing requirements.

  • Why traditional routing fails (5 key reasons)
  • WSN routing requirements
  • Common pitfalls to avoid
  • Energy efficiency, scalability, and robustness

434.3.3 3. WSN Routing Classification

Protocol categories and tradeoffs

WSN routing protocols are classified into four major families. This section covers the classification, key tradeoffs (proactive vs reactive, flat vs hierarchical), and includes an interactive LEACH clustering demonstration.

  • Data-centric, hierarchical, location-based, and QoS-aware protocols
  • Proactive vs reactive routing tradeoffs
  • Flat vs hierarchical routing comparison
  • Single-path vs multi-path routing
  • Interactive LEACH clustering demo

434.4 Quick Reference: Protocol Selection

Scenario Recommended Protocol Rationale
Event-driven monitoring Directed Diffusion Data-centric, responds to queries
Dense deployment (>100 nodes) LEACH/PEGASIS Hierarchical aggregation scales
GPS-equipped nodes GPSR/GEAR Geographic forwarding efficient
Real-time alerts QoS protocols (SPEED) Latency guarantees
Stable topology Proactive (DSDV) Routes ready immediately
Mobile nodes Reactive (AODV) Adapts to changes
Code updates Trickle Low overhead when consistent

434.5 What’s Next

Start with WSN Routing Introduction to understand why WSN routing differs from traditional networking. If you’re already familiar with WSN challenges, skip to WSN Routing Classification to explore protocol families and tradeoffs.

After completing this chapter series, proceed to:

Deep Dives:

Protocols:

Learning:

434.6 Further Reading

  1. Intanagonwiwat, C., et al. (2003). “Directed diffusion for wireless sensor networking.” IEEE/ACM Transactions on Networking, 11(1), 2-16.

  2. Heinzelman, W. R., et al. (2000). “Energy-efficient communication protocol for wireless microsensor networks.” HICSS, 2, 10.

  3. Akyildiz, I. F., et al. (2002). “A survey on sensor networks.” IEEE Communications Magazine, 40(8), 102-114.

  4. Fasolo, E., et al. (2007). “In-network aggregation techniques for wireless sensor networks: A survey.” IEEE Wireless Communications, 14(2), 70-87.