Abstract:
Recent advancements in iterative processing of channel codes and the
development of turbo codes have allowed the communications industry to
achieve near-capacity on a single-antenna Gaussian or fading channel with
low complexity. We show how these iterative techniques can also be used to
achieve near-capacity on a multiple-antenna channel. Combining iterative
processing with multiple-antenna channels is particularly challenging
because the channel capacities can be a factor of ten or more higher than
their single-antenna counterparts. Using a ``list" version of the sphere
decoder, we provide a simple method to iteratively detect and decode any
linear space-time mapping combined with any channel code that can be
decoded using so-called ``soft" inputs and outputs. We exemplify our
technique by directly transmitting symbols that are coded with a channel
code; we show that iterative processing with even this simple scheme can
achieve near-capacity. We consider both simple convolutional and powerful
turbo channel codes and show that excellent performance at very high data
rates can be attained with either. We compare our simulation results with
Shannon capacity limits for ergodic multiple-antenna channels.
Status: Appears in
Proceedings of Allerton Conf. on Communication, Control and
Computing, Oct. 2001, and IEEE Transactions on Communications, March 2003.
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