Asymmetric Quantizers Are Better at Low SNR

Tobias Koch; Amos Lapidoth

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arXiv · 1101.0970

Asymmetric Quantizers Are Better at Low SNR

Tobias Koch·Amos Lapidoth

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Abstract

We study the behavior of channel capacity when a one-bit quantizer is employed at the output of the discrete-time average-power-limited Gaussian channel. We focus on the low signal-to-noise ratio regime, where communication at very low spectral efficiencies takes place, as in Spread-Spectrum and Ultra-Wideband communications. It is well know that, in this regime, a symmetric one-bit quantizer reduces capacity by 2/pi, which translates to a power loss of approximately two decibels. Here we show that if an asymmetric one-bit quantizer is employed, and if asymmetric signal constellations are used, then these two decibels can be recovered in full.

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Tobias Koch, Amos Lapidoth. 2011-05-30. Asymmetric Quantizers Are Better at Low SNR. https://arxiv.org/abs/1101.0970

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