Microsoft powerpoint tmp tutoriel 112007 final

Epi

Sujets

• Informatique
• Marketing et communication

Informations

• Publié par: oeufdepaques
• Nombre de lectures: 183
• Langue: Français
• Poids de l'ouvrage: 5 Mo

Extrait

Terrestrial Mobile TV Technologies & Implementation

PARIS – 28 th November 2007 Eric PINSON

©Teamcast- - 2007  

Presentation plan

Terrestrial Transmission Channel

Channel perturbations

COFDM signal fundamentals

Terrestrial Mobile TV implementations (DVB-H, FLO)

1

Hybrid Mobile TV implementations (DVB-SH, CMMB)

©Teamcast- - 2007  

Commercial in Confidence

2

3

4

5

2

Presentation plan

1

2

3

4

5

Terrestrial Transmission Channel

Channel perturbations

COFDM signal fundamentals

Terrestrial Mobile TV implementations (DVB-H, FLO)

1 2 3 4 5 TransmissionChannel

Hybrid Mobile TV implementations (DVB-SH, CMMB)

©Teamcast- - 2007  

Commercial in Confidence

3

2 3 4 5 Transmission Channel behavior for fixed reception TransmissionChannel



dB

0

µs

Channel Time Response

Channel Frequency Response

0

The channel frequency response is not constant Some frequencies will be attenuated (FADING), other will be reinforced The channel time response points out the presence of signal echoes

©Teamcast- - 2007  

Commercial in Confidence

Main path with echoe(s)

Spectrum with fading

4

 

Channel Response in Mobility

T 0

T 1

H(f) 10dB

0dB

-10dB

-20dB -30dB

In mobile reception, the frequency re sponse of the channel always changes So, it is necessary to realize atime predictionat the reception to This implies the implementation of Time Interleaves

©Teamcast- - 2007  

Commercial in Confidence

2 3 4 5 TransmissionChannel

f

5

2 3 4 5 Estimation of the transmission channel TransmissionChannel



Modulation

Coding

Analyzing the transmission chan nel allows to extract the useful data  Channel estimation in frequency domain (fading correction) and in time domain (mobile)

©Teamcast- - 2007  

Commercial in Confidence

Channel estimation

Demodulation

Decoding

Correction

6

Presentation plan

1

2

3

4

5

Terrestrial Transmission Channel

Channel perturbations

COFDM signal fundamentals

Terrestrial Mobile TV implementations (DVB-H, FLO)

Hybrid Mobile TV implementations (DVB-SH, CMMB)

©Teamcast- - 2007  

Commercial in Confidence

2 3 4 5 Channel   Perturbations

7