Crosstalk Cancellation in Base-band Parallel Communication Buses
Speaker: Michael Chan, ITEE
When: 2005-07-28 13:00:00
Venue: 78-420
Host: Dr Adam Postula
Abstract:Crosstalk interference is the principle factor limiting the
performance of parallel buses. The magnitude of this interference
is proportional to the slew rate of signals, which directly relates
to the signalling rate. At the multi gigabit per second data rates
demanded of today's high speed links, crosstalk interference in a
parallel bus can be comparable to the magnitude of the signals being
transmitted rendering such a link unusable. Even at a fraction of
these data rates, crosstalk renders useless all but the most
carefully designed systems. For this reason, there has in recent
years been a move from parallel communications to serial
communications schemes. Examples of this trend include the
development of Serial ATA, PCI-X, and Hyper-Transport. If one were
able to cancel out the negative effects of crosstalk, it may be
possible to design parallel links with symbol rates approaching that
of their serial counterparts. This would result in ultra-high
bandwidth interconnections due to the throughput advantage of a
parallel channel.
My project will investigate how the performance of base-band
parallel communication systems can be improved by treating a
parallel channel as a multiple input / multiple output (MIMO)
system, and using MIMO techniques to cancel crosstalk interference.
Typical approaches to crosstalk mitigation have fallen into three
categories. The first category has focused on careful layout of
signal paths coupled with shielding and pulse shaping to minimize
the interference between adjacent lines in a bus. Another class of
approaches has focused on finding spatial and temporal encoding
methods so that worst case crosstalk scenarios are avoided. The
third class has looked at predicting the crosstalk interference
effected by nearest neighbour lines and compensating for it at the
receiver, or by using pre-distortion at the transmitter.
My approach falls into the third category, but is more general in
that it will attempt to cancel crosstalk caused by all the signal
lines. By treating a parallel channel as a MIMO system, crosstalk
is simply an aspect of that systems transfer function, and can be
compensated for by equalizing the channel using a multi-dimensional
equalizer. My project will look at how effective this is, the
complexity of the scheme, and how best to divide the equalization
between the transmitting side and receiving side. In particular, I
plan to construct area efficient analogue and mixed signal solutions
for ASIC implementation.
Biography:(biography unavailable)
Type: Ph.D confirmation
Contact:Dr Adam Postula, seminar host (adam@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)