MassiveMIMO

Abstract

Massive MIMO, where MIMO stands for multiple‐input multiple‐output, is a multiuser‐MIMO (MU‐MIMO) cellular communication technology with a massive number of antennas and users. More precisely, each base station (BS) is equipped with a large number of antennas and utilizes these antennas to spatially multiplex many user equipments (UEs) on the same time‐frequency resource. The main difference from conventional cellular networks is that the interference between UEs is managed by spatial processing (called transmit precoding or receive combining) instead of by scheduling them on orthogonal time‐frequency resources. The key differentiator from conventional MU‐MIMO systems is that the users' channels become nearly orthogonal – a property referred to as “favorable propagation” – when the BS has a large number of antennas. This property vastly reduces the interference and thus allows for spatial multiplexing of many tens of UEs, instead of a handful UEs. In addition, favorable propagation enables the use of relatively simple linear signal processing techniques for interference suppression.