SOME SECURITY ISSUES

Introduction

What is Cognitive Radio?

Spectrum Sensing

Primary User Emulation

Simulation & Results

OVERVIEW

Evolution of numerous wireless applications.

Limited Public Bandwidth or Spectrum

Inefficient use of Licensed Spectrum

What if one could use the licensed spectrum when no primary users are using it?

INTRODUCTION

Intelligent Radio.

Senses Environment and Spectrum(Cognitive capability).

Analyzes it(Self-organized capability).

Adapts to it(Reconfigurable capability).

Learns from the results.

WHAT IS COGNITIVE RADIO?

General Architecture of Cognitive Radio

Dynamic Spectrum Access (DSA)

Distributed Spectrum Sensing (DSS)

Common Control Channel (CCC)

SPECTRUM SENSING

Dynamic Spectrum Access (DSA)

Distributed Spectrum Sensing (DSS)

Common Control Channel (CCC)

SPECTRUM SENSING

Dynamic Spectrum Access (DSA)

Distributed Spectrum Sensing (DSS)

Common Control Channel (CCC)

SPECTRUM SENSING

CCC

CooperationOptimization

Matched Filter

Cyclo-Stationary Feature

Energy Detection

SPECTRUM SENSING TECHNIQUES

Matched Filter

Cyclo-Stationary Feature

Energy Detection

SPECTRUM SENSING TECHNIQUES

Matched Filter

Cyclo-Stationary Feature

Energy Detection

SPECTRUM SENSING TECHNIQUES

Idle spectrum can be used by secondary users without causing disturbance to the primary user.

But these secondary users must co-operate and use the spectrum fairly.

Some secondary users prevent others from using this idle spectrum by transmitting unrecognizable signals.

i.e. they emulate (imitate) the primary users and hence prevent secondary users from utilizing it.

They are of two types: Selfish PUE attackers Malicious PUE attackers

PRIMARY USER EMULATION

SYSTEM MODEL FOR CRNs

Received power due to Primary Transmitter, Pr_p

PDF of Pr_p

Received power due to Malicious users, Pr_m

PDF of Pr_m

The following slides contain the simulated

results of the PDFs of signals received by the

secondary receiver due to primary

transmitter and malicious users.

SIMULATION & RESULTS

SYSTEM MODEL FOR CRNs

As it can be seen, the results of the previous

system model are not desirable.

So, another system model is presented to

counteract the PUE.

SYSTEM MODEL ALTERATION

PROPOSED MODEL

THOUGHTS OR QUERIES?