Random Access Protocols for Massive MIMO

TL;DR

This paper discusses how Massive MIMO technology enables efficient random access protocols in 5G networks, supporting dense device connectivity with high data rates and low latency, especially in scenarios with many devices and short channel coherence times.

Contribution

It introduces and analyzes three novel pilot access protocols tailored for Massive MIMO in 5G, addressing the challenges of dense device environments and short coherence intervals.

Findings

Massive MIMO significantly enhances random access efficiency.

Proposed protocols support diverse 5G service requirements.

Protocols enable fast and delay-tolerant data transmission.

Abstract

5G wireless networks are expected to support new services with stringent requirements on data rates, latency and reliability. One novel feature is the ability to serve a dense crowd of devices, calling for radically new ways of accessing the network. This is the case in machine-type communications, but also in urban environments and hotspots. In those use cases, the high number of devices and the relatively short channel coherence interval do not allow per-device allocation of orthogonal pilot sequences. This article motivates the need for random access by the devices to pilot sequences used for channel estimation, and shows that Massive MIMO is a main enabler to achieve fast access with high data rates, and delay-tolerant access with different data rate levels. Three pilot access protocols along with data transmission protocols are described, fulfilling different requirements of 5G services.