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CONTENTS

Introduction Wi-com Through Soil Using EM Waves 2-path Rayleigh Fading Channel Model Wi-com Through Soil Using Magnetic Induction Practical Approach Paging Systems Critical Requirements

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INTRODUCTION

Wireless Underground Communication Networks(WUCNs) constitute one of the promising applicationareas of the recently developed wireless networking

techniques. The WUCNs consist of wireless devicesthat operate below the ground surface. These devicesare either(i) Buried completely under dense soil or(ii) Placed within a bounded open underground space

such as underground mines and road/subway tunnels.

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Wi-com through soil using EM

wavesEM waves encounter much higher attenuation in soilcompared to air. This severely hampers thecommunication quality. Moreover, the ground

surface causes reflection as well as refraction,which requires a comprehensive investigation of thechannel model. Therefore, advanced models arenecessary to accurately and completely

characterize the underground channel and to lay outthe foundations for efficient undergroundcommunication.

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Design Considerations ForChannel

Signal propagation through soil Pr = Pt + Gr + Gt Lp Reflection from ground surface

Multi-path fading Characteristics of EM waves in soil Modulation scheme Operation frequency and deployment depth

Transmit power and volumetric water content

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Wi-com through soil usingmagnetic induction

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Practical Approach

Communications with underground mining vehicles

normally are by low frequency FM carrier equipmentcoupled to the trolley wire of electric locomtivesoperating on an extensive track system. Low frequency(100 KHz) wireless systems offer good mine coverageby the deliberate coupling of a base Station receiver

and transmitter to the mine power system.

Vehicular Communications 2500 ftUnderground

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Critical Requirements

Stability:Power system stability basically refers to the abilityof operating an AC network with all generators insynchronism, retaining synchronism even after a

large disturbance

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Hierarchical Robust PowerSystem Controller

Execution Levelo Signal pre-processoro Actuator / Distributor

Operation Levelo System modal identifiero Damping loop

Management Levelo Fuzzy logic based parameter tuner

PowerSystem

Management Level

Operation Level

Execution Level

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Intentionalhuman acts

Network

Information &decisions

InternalSources

ExternalSources

Security refers to the ability of the system to respond onlyto intended operator commands, blocking all unintendedoperations.

MarketCommunicationsystems

Natural calamities

Security

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Energy management

systemsArchiving

E M S

Operator interaction State estimator

Generatorcontrols

Sensoryinformation

Command and control

Time synchronization (GPS)

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Strategic power

infrastructuremain system

Time synchronization (GPS)/ Self healing / Info.Exchange (LEO)

IntranetEthernet or model based networkis used in the Intranet. EachIntranet can have a gateway thathandles IP addresses in theIntranet

Internet or any othercommunication channelfor a number of Intranets

GPS or LEO satellitecommunication

Internet based

communicationchannel

Internet based or moredirect and fastercommunicationchannel

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THANKS