Massive MIMO: How many antennas do we need?

Preprint
Publisher Website
Google Scholar
Abstract
We consider a multicell MIMO uplink channel where each base station (BS) is equipped with a large number of antennas N. Recent work has shown that, as N grows infinitely large, (i) the simplest form of user detection, i.e., the matched filter (MF), becomes optimal, (ii) the transmit power per user terminal (UT) can be made arbitrarily small, (iii) the system performance is limited by pilot contamination. The aim of this paper is to assess to which extent the above conclusions hold true for large, but finite N. In particular, we derive how many antennas per UT are needed to achieve \eta % of the ultimate performance. We then study how much can be gained through more sophisticated minimum-mean-square-error (MMSE) detection and how many more antennas are needed with the MF to achieve the same performance. Our analysis relies on novel results from random matrix theory which allow us to derive tight approximations of the signal-to-interference-plus-noise-ratio (SINR) of a class of linear receivers.

This publication has 0 references indexed in Scilit: