Avoiding Energy Holes in Wireless Sensor Network with Nonuniform Node Distribution

Xiaobing Wu, Guihai Chen and Sajal K. Das

Parallel and Distributed Systems 2008

Outline Introduction

Energy Hole Problem Analysis of the Nonuniform Node Distribution Str

ategy Impossibility of Balanced Energy Depletion Possibility of Subbalanced Energy Depletion

Novel Nonuniform Node Distribution Strategy and q-switch Routing

Simulation

Energy Hole Problem in Sensor Network

Energy hole: Unbalanced energy utilization

Some nodes deplete their power more quickly

Sink

Energy hole

Energy hole

Sink

Energy hole

Sink

Related Work

Approaches that have been proposed to mitigate the energy hole problem Sink mobility Multiple sinks Hierarchical deployment

Clustering Non-uniform initial energy budgets Non-uniform node distribution

The objective of this paper

Contributions of this paper

1. Prove that balanced energy utilization is impossible for many-to-one traffic pattern.

2. Prove that subbalanced energy utilization is possible

3. Propose a nonuniform node deployment strategy

4. Propose a q-switch routing

Assumptions and Network Model

Assume that all the nodes are deployed in a circular area with a radius R

The width of each corona is 1 unit length Maximum transmission range is 1 unit length Nodes belonging to a corona will forward data generated by both themselves and nodes from coronas

{ | }iC i R

{ | 1 }jC i j R

Assumptions and Network Model

Assume that each sensor node generates and sends L bits of data per unit time

Regular reporting The initial energy of each sensor is Sending 1 bit costs e1 units of energy

Receiving 1 bit costs e2 units of energy

Energy Consumption

Ni : the number of nodes in Ci

Ei: the energy consumed per time unit

by nodes in Ci

Balanced v.s. Subbalanced

Impossibility of Balanced Energy Depletion

Proof

If balanced energy depletion is achieved, then

Average energy consumption per node

Impossibility of Balanced Energy Depletion

Subbalanced Energy Depletion

Proof: If the network achieves the subbalanced energy depletion

Average energy consumption per node

Subbalanced Energy Depletion

Subbalanced Energy Depletion

the number of nodes in coronas increases in geometric progression with a common ratio of q

Nonuniform Node Distribution-- Subbalanced Energy Depletion

81648144

q=3

Nonuniform Node Distribution-- Subbalanced Energy Depletion

Proof

Nonuniform Node Distribution-- Subbalanced Energy Depletion

Nonuniform Node Distribution Strategy

The number of nodes in Ci

Subbalanced Energy Depletion

Nonuniform Node Distribution Strategy

q-Switch Routing

Simulation

Conclusion

This paper explored the theoretical aspects of the nonuniform node distribution strategy in WSNs.

Although it is impossible to achieve balanced energy depletion, subbalanced energy depletion in the network is possible.