Three Practical Aspects of Massive MIMO: Intermittent User Activity, Pilot Synchronism, and Asymmetric Deployment

TL;DR

This paper investigates three key practical aspects of Massive MIMO systems—intermittent user activity, pilot synchronization, and deployment randomness—and provides analytical insights into their effects on spectral efficiency.

Contribution

It offers the first comprehensive analysis of how bursty traffic, pilot timing, and deployment randomness influence Massive MIMO performance.

Findings

Spectral efficiency scales well with reduced user activity.

No difference in spectral efficiency between synchronous and asynchronous pilot signaling.

Random deployment impacts spectral efficiency, supported by analytical and numerical results.

Abstract

This paper considers three aspects of Massive MIMO (multiple-input multiple-output) communication networks that have received little attention in previous works, but are important to understand when designing and implementing this promising wireless technology. First, we analyze how bursty data traffic behaviors affect the system. Using a probabilistic model for intermittent user activity, we show that the spectral efficiency (SE) scales gracefully with reduced user activity. Then, we make an analytic comparison between synchronous and asynchronous pilot signaling, and prove that the choice between these has no impact on the SE. Finally, we provide an analytical and numerical study of the SE achieved with random network deployment.