Pilot Coordination in CDI Precoded Massive MIMO Systems

Pilot contamination severely degrades the achievable rates in massive MIMO systems. To resolve the problem, many channel state information (CSI) and channel distribution information (CDI) methods were developed. This paper presents a CDI based pilot coordination method that leads to a considerable improvement in the achievable sum rate. It also shows that pilot assignment can drastically affect sum rate performance and describes a method that avoids worst-case conditions.