Multi-Cell Multiuser Massive MIMO Networks: User Capacity Analysis and Pilot Design

TL;DR

This paper introduces a new pilot sequence design and power allocation method for multi-cell massive MIMO networks, significantly improving user capacity and reducing antenna requirements while meeting SINR targets.

Contribution

It proposes a novel pilot sequence and power allocation scheme with closed-form capacity expressions, enhancing user capacity and efficiency over existing methods.

Findings

Achieves larger user capacity region than existing designs.

Reduces the number of antennas needed at base stations.

Provides closed-form expressions for user capacity and SINR requirements.

Abstract

We propose a novel pilot sequence design to mitigate pilot contamination in multi-cell multiuser massive multiple-input multiple-output networks. Our proposed design generates pilot sequences in the multi-cell network and devises power allocation at base stations (BSs) for downlink transmission. The pilot sequences together with the power allocation ensure that the user capacity of the network is achieved and the pre-defined signal-to-interference-plus-noise ratio (SINR) requirements of all users are met. To realize our design, we first derive new closed-form expressions for the user capacity and the user capacity region. Built upon these expressions, we then develop a new algorithm to obtain the required pilot sequences and power allocation. We further determine the minimum number of antennas required at BSs to achieve certain SINR requirements of all users. Numerical results are presented to corroborate our analysis and to examine the impact of key parameters, such as the pilot sequence length and the total number of users, on the network performance. A pivotal conclusion is reached that our design achieves a larger user capacity region than the existing designs and needs less antennas at the BS to fulfill the pre-defined SINR requirements of all users in the network than the existing designs.