FODA/IBEA TDMA Modem


Project

FODA/IBEA TDMA Modem


Development Team

CNUCE, Telespazio, ESA, et al


Funding

COST 226 / as above


Use

R & D of new TDMA modem technology


Status

Prototype being tested at CNUCE, further R & D.


Transponder

Ku-Band Eutelsat. 3-4 Terminals in network with main sites at Pisa and Florence. (3.5m Antenna)

Ka-Band


Access

FODA scheme using reservations for multimedia traffic. A free-space allocation scheme is also supported.


Speed

8 Mbps (uncoded) + 3 bit sign/mag soft decision demod.

The Integrated Bit Energy Adaptor (IBEA) uses 1/2 rate, 2/3 rate, 4/5 rate FEC and uncoded. (Lower rates are obtained by puncturing a convolutional code.) Each burst contains a preamble indicating the coding and modulation of the sub bursts. QPSK or BPSK modulation is used. The deepest fade which still maintains operation is about Eb/No of 4.5 dB (12 dB gain for modifying the data rate and a 2 dB gain from the coding.)


Terrestrial Net Interface

RS-449, G.703, 64 kbps voice, and Enet bridge. Data is seperated into stream and datagram with VBR support to be added soon.


B-ISDN Signalling?

No


Terrestrial Phys Interface

RS-449, G.703, 64 kbps voice, and Enet.


Notes

The system allows efficient use of TDMA. Provision is also made for ToS support for real-time traffic using priority in the access scheme. A direct ATM interface is being considered. See also the more general information under the COST 226 programme (COST 226 MF-SS-TDMA Modem).

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Gorry Fairhurst - ERG home page