A Survey of Energy-Efficient Scheduling Mechanisms in

Sensor Networks

Author： Lan Wang·Yang Xiao(2006)

Presented by Yi Cheng Lin

Outline

Introduction Classification methodology

– Design assumptions– Design objectives

Energy saving modes of sensors Distributed scheduling mechanisms in non-

hierarchical networks Classification

Introduction

Sensor networks have a variety of application in both military and civil environment

These sensors usually operate on limited battery power

An important design objective: minimizing energy consumed by sensing and communication to extend the lifetime

Design assumptions

Design objectives

Energy saving modes of sensors

Distributed scheduling mechanisms in non-hierarchical networks

Random independent scheduling (RIS)– Time is divided into cycles based on time

synchronization method– Active with probability p or go to sleep with

probability 1-p (p determines the network life)– Sensor deployment strategies

Grid, random, uniform, and 2-dimensional Poisson

Sponsored sector

– Preserving sensing coverage

– Off- duty sponsors, sponsored sector

– Use neighbor’s location information and sensing range

Maximization of sensor network life (MSNL)

– K-coverage– Three states: active, idle or vulnerable– Nodes need to broadcast their state and energy level

Lightweight deployment-aware scheduling (LDAS)

No need location information

Each working node has a mechanism to know the number of working nodes in its neighbor

Probing environment and adaptive sensing (PEAS)

– High-density sensor network in a harsh environment– Conserve energy by separating all the working nodes

by a minimum distance of c– Unbalanced energy consumption

Optimal geographic density control (OGDC)– Maximize the number of sleeping sensor– Ensure 1-coverage and 1-connectivity– Minimize the overlapping area

Coverage configuration protocol (CCP)

Maintain K-coverage and K-connectivity

Combine CCP and SPAN

Three modes: ACTIVE, LISTEN, SLEEP

Adaptive self-configuring sensor networks topologies (ASCENT)

– Goal: Maintain certain data delivery ratio– Unfair energy consumption

Probing environment and collaborating adaptive sleeping (PECAS)

– Probe message– Prevent the occurrence of blind spots– Energy saving lower than PEAS

Classification based on assumption

Classification based on objectives