nghia PHAM writes:
It can be shown that:
Raw BER= 2E-2,
==> BER =2E-4 after inner FEC (with soft decision decoding)
==> BER<1E-11 after outer FEC decoding
This is less than one error event per hour, at 40Mbit/s user bit rate.
[...]
4) Furthermore, it can be shown that when the RS cannot
decode it produces very large strings of errors. Usually, the block
code synchronisation fails as well. This occurs
at raw BER=5E-2 approximately.
Since you refer to direct video broadcasting, I assume you consider
continuous mode transmissions only.
Does anybody have any data for burst modems (to be used in TDMA
systems)?
Our experience suggests that the problem with burst modems is not in
the corruption of data, which is easily corrected for with layered
coding, but in the burst acquisition probability, which drops to
unacceptable levels when Eb/No is less than about 7 dB (QPSK).
Comments welcome.
--
Francesco Potorti` (researcher) Voice: +39-50-593 203 (op. 211)
Computer Networks Group Fax: +39-50-904052
CNUCE-CNR, Via Santa Maria 36 Email: [email protected]
56126 Pisa - Italy Web: http://fly.cnuce.cnr.it/
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