RELIABLE MULTIMEDIA TRANSMISSION OVER COGNITIVE RADIO NETWORKS USING FOUNTAIN CODES Proceedings of the IEEE | Vol. 96, No. 1, January 2008 Harikeshwar Kushwaha, Student Member IEEE, Yiping Xing, Student Member IEEE, Rajarathnam Chandramouli, Senior Member IEEE, and Harry Heffes, Fellow IEEE 1

Outline 2

Introduction 3  Wireless multimedia applications require  significant bandwidth and  satisfying relatively tight delay constraints.  Radio spectrum is a scarce resource.  spectrum has already been allocated.  Secondary spectrum access(FCC)  dynamic access to the unused parts of the spectrum owned by the primary license holder  facilitated by Cognitive radios

Introduction 4

Spectrum Pooling Concept 5

6  A link is composed of multiple different SCs at different frequencies.  achieving distributed streaming  Reliable  But, the coordination required between the SCs.

Digital Fountain Codes 7  No need of coordination required between the SCs.  Robust against the packet loss caused by the PU interference and other channel conditions.

Primary User Arrival Model 8

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Coding Scheme for Scalable Multimedia Applications 10

Problem description 11 How many?

Problem description 12

Subchannel Selection 13

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Simulation Result 20

Simulation Result - Parameterization 21  1) Estimation of Number of Required Subchannels:

Simulation Result - Parameterization 22

Simulation Result - Parameterization 23  2) LT Codes(ideal case) ： robust soliton distribution

Simulation Result - Parameterization 24  3) Delay and Other Requirements:

Simulation Result - Parameterization 25

Simulation Result - Parameterization 26

Simulation Result – Performance Analysis 27  Observation in Figs ： 1) Dependence on X For each value of S, attains a maximum value at a specific value of X. 2) Dependence on S η attains another maximum at a specific value of S. 3) Dependence on λ η decreases as λ increases

Conclusion 28  Propose a scheme for the transmission of distributed multimedia applications over cognitive radio networks with the help of digital fountain codes.  For a given λ and number of original packets K, we can find out the value of the optimum number of SCs and the overhead X that give maximum spectral efficiency.