Abstract:
Recent theoretical results describing the sum-capacity when using
multiple antennas to communicate with multiple users in a known rich
scattering environment have not yet been followed with practical
transmission schemes that achieve this capacity. We introduce a
simple encoding algorithm that achieves near-capacity at sum-rates
of tens of bits/channel-use. The algorithm is a variation on
channel inversion that regularizes the inverse and uses a "sphere
encoder" to perturb the data to reduce the energy of the
transmitted signal. The performance difference between channel
inversion with and without this perturbation is shown to be
dramatic. With the perturbation, we can achieve linear growth in
the sum-rate with the number of users. The results of
both uncoded and turbo-coded simulations are presented.
Status:
Proceedings of the 41st Allerton Conference on Communication, Control,
and Computing, October 2003. Also
submitted to IEEE Transactions on Communications, June 2003.
Part I files:
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PostScript (.ps) (199K),
PDF v3.0 (.pdf) (145K).
Part II files:
Compressed PostScript (.ps.gz) (72K),
PostScript (.ps) (227K),
PDF v3.0 (.pdf) (164K).
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