implementation of synchronization algorithms for media flo systems

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Implementation of Synchronization Algorithms for Media Flo Systems

ByAhmad ElMoslimany

Supervised by:Prof. Mirette Sadek

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Agenda• Introduction to Media FLO system• Media FLO Transmitter• Media FLO Receiver– Synchronization– Equalizer– Turbo decoder– Reed Solomon decoder

• Simulation results & !!!!!!

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What is Media FLO?

•American standard for video broadcast.•Mainly used in mobile TV.•An OFDM based system.

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OFDM Overview

• Multicarrier modulation.• Orthogonality.

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OFDM Overview (cont’d)• Cyclic Prefix Addition.• Avoid ISI and ICI.

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FLO TransmitterBlock diagram:

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Super frame Structure

• OFDM symbol = 4000 active sub-carrier• B.W = 5.55 MHz• Frequency spacing = 1.35 KHz

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FLO ReceiverBlock diagram:

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Synchronization• Synchronization theory.• Application of synchronization algorithms in

Media FLO system.

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Media FLO system.

Synchronization theory

Synchronization types

Frame synchroniza

tion

CFO estimation

Trigger point estimation

Synchronization theory (cont’d)

Synchronization Algorithms

Pilot aided method Blind method

Frame synchronization

• Detect the start of the frame.

• Search for known preamble.

• OFDM preamble has unique properties.

• Based on correlation technique.

Carrier Frequency Offset (CFO)

•Local oscillators mismatch.• ICI occurs. •Loss of orthogonality.

CFO(cont’d)• Fine frequency offset, Through maximum

likelihood estimator

• Coarse frequency offset, through correlation process.

1* )()()(

)(21

Lm

mk

ML

Nkrkrm

Trigger point estimation

•Select NFFT window.• Avoid ISI.

Synchronization (cont’d)


pilot aided method Blind method

Blind Method

coarse trigger point estimation through ML estimator

1-Lm22

1*

ML

.|N)r(k||r(k)|21)(

).()()(

}.|)(-)(|{maxarg

mk

Lm

mk

m

Nkrkrm

Synchronization (cont’d)


pilots aided method Blind method

Pilots Aided MethodTrigger point fine tuning using pilots aided method

using the following metric.

).(minarg

0

],0[0)(

)(|h(m)|)(

,0

1L

0m2c

qPt

nnGnGnGn

nf

qmfqP

IBIqfine

IBI

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Media FLO system.– Frame synchronization• Blind method• Pilots aided method

– Symbol synchronization– Carrier frequency offset estimation

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Media FLO system.– Frame synchronization– Symbol synchronization• Blind method• Pilots aided method

– Carrier frequency offset estimation


Block diagram :

Frame synchronization (cont’d)

• Correlation properties of TDM1

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• Running cross correlation between TDM1 and another symbol


• Correlation properties of TDM1 (cont’d)

Frame synchronization (cont’d)

• Peaks of cross correlation

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Maximum Likelihood (ML) estimator

Block diagram :

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Outputs from ML

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Outputs from ML (cont’d)

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Performance of ML

• Histogram of the estimated trigger point

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Performance of ML (cont’d)

• Histogram of the estimated fine CFO

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Trigger Point tuning using pilot aided method

• Block diagram :

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CIR estimated

Performance of the fine tuner

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TDM1 correlation

• Cross and Auto correlation of TDM1, CFO=1

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TDM1 correlation

• Cross and Auto correlation of TDM1, CFO=2

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Coarse CFO estimatorPeaks of the correlation

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• Simulation results

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Simulation results

• AWGN , mode 0 (QPSK ,TR=1/3 ,RS=7/8)

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Simulation results (cont’d)

• AWGN , mode 2 (16QAM ,TR=1/3 ,RS=7/8)

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• TU6 ,mode 0

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• TU6 ,mode 2

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Any Questions ?

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Thank You

implementation of synchronization algorithms for media flo systems

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