Engineers at
Pennsylvania State University in the US are attempting
to achieve data speeds of 100 gigabits per second over Cat 7 copper
cables. If successful, it could pave the way for copper cables able
to handle the same data rates as more expensive fibre optic
links.
"A rate of 100gbps over 70 metres is definitely possible, and we
are working on extending that to 100 metres," said Ali Enteshari,
graduate student in electrical engineering and part of the research
team.
These cables are used to connect computers within a room or a
building, or to create parallel computing systems.
Although the long-distance lines of most internet systems are
glass fibre optic cables, which offer fast data transfer, copper
cable is generally used for short distances.
All transmission cables are limited by the distance they can
transmit data without degradation of the signal. Before errors and
interference make the signals non-recoverable, cable systems use
repeaters - which are similar to computer modems - to capture,
correct or recover data, and resend it. The distance between
repeaters depends on the cable and the approach used by the modem
to correct errors.
"What we are offering is a less expensive solution and one that
is easier to build," said Jarir Fadlullah, a graduate student on
the Pennsylvania research team.
Using information on specifications and characteristics of the
cables, the researchers modelled the cable with all its attributes,
including modelling crosstalk. They then designed a
transmitter/receiver equipped with an interference canceller that
could transfer up to 100gbps using error correcting and equalizing
approaches.
"However, the design of a 100gbps modem might not be physically
realisable at this time as it is technology limited. We are
providing a roadmap to design a high speed modem for 100gbps," said
Enteshari.
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