Co-existing/Cooperating Multicell Massive MIMO and Cell-Free Massive MIMO Deployments: Heuristic Designs and Performance Analysis

TL;DR

This paper analyzes the coexistence of cell-free and multicell massive MIMO systems, proposing heuristic cooperation strategies and evaluating their impact on downlink performance through extensive simulations.

Contribution

It introduces a fronthaul-aware heuristic association algorithm and evaluates the performance of co-existing massive MIMO deployments with various cooperation levels.

Findings

Coexistence impacts downlink performance significantly.

Heuristic association improves fronthaul efficiency.

Different cooperation strategies yield diverse performance trade-offs.

Abstract

Cell-free massive MIMO (CF-mMIMO) systems represent a deeply investigated evolution from the conventional multicell co-located massive MIMO (MC-mMIMO) network deployments. Anticipating a gradual integration of CF-mMIMO systems alongside pre-existing MC-mMIMO network elements, this paper considers a scenario where both deployments coexist, in order to serve a large number of users using a shared set of frequencies. The investigation explores the impact of this co-existence on the network's downlink performance, considering various degrees of mutual cooperation, precoder selection, and power control strategies. Moreover, to take into account the effect of the proposed cooperation scenarios on the fronthaul links, this paper also provides a fronthaul-aware heuristic association algorithm between users and network elements, which allows the fulfillment of the front-haul requirement on each link. The research is finally completed by extensive simulations, shedding light on the performance outcomes associated with the various levels of cooperation and several solutions delineated in the paper.