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Terrestrial Mobile TV Technologies & Implementation
PARIS 28thNovember 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 receptionTransmissionChannel
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
T0
T1
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 channelTransmissionChannel
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
