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A Vector-Perturbation technique for Near-Capacity . . . (2005)
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| Venue: | IEEE TRANS. COMMUN |
| Citations: | 322 - 10 self |
BibTeX
@ARTICLE{Peel05avector-perturbation,
author = {Christian B. Peel and Bertrand M. Hochwald and A. Lee Swindlehurst},
title = {A Vector-Perturbation technique for Near-Capacity . . . },
journal = {IEEE TRANS. COMMUN},
year = {2005},
volume = {53},
number = {1},
pages = {195--202}
}
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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 power of the transmitted signal. This paper is comprised of two parts. In this first part, we show that while the sum capacity grows linearly with the minimum of the number of antennas and users, the sum rate of channel inversion does not. This poor performance is due to the large spread in the singular values of the channel matrix. We introduce regularization to improve the condition of the inverse and maximize the signal-to-interference-plus-noise ratio at the receivers. Regularization enables linear growth and works especially well at low signal-to-noise ratios (SNRs), but as we show in the second part, an additional step is needed to achieve near-capacity performance at all SNRs.
Keyphrases
vector-perturbation technique sum capacity sum rate channel inversion second part first part multiple antenna channel matrix transmitted signal practical transmission scheme signal-to-interference-plus-noise ratio multiple user linear growth simple encoding algorithm low signal-to-noise ratio sphere encoder singular value large spread poor performance bit channel use recent theoretical result additional step near-capacity performance
