HBF MU-MIMO With Interference-Aware Beam Pair Link Allocation for Beyond-5G mm-Wave Networks

IEEE Transactions on Mobile Computing, vol. 24, pp. 4248–4262

Abstract

Hybrid beamforming (HBF) multi-user multiple-input multiple-output (MU-MIMO) is a key technology for unlocking the directional millimeter-wave (mm-wave) nature for spatial multiplexing beyond current codebook-based 5G-NR networks. In order to suppress co-scheduled users' interference, HBF MU-MIMO is predicated on having sufficient radio frequency chains and accurate channel state information (CSI), which can otherwise lead to performance losses due to imperfect interference cancellation. In this work, we propose IABA, a 5G-NR standard-compliant beam pair link (BPL) allocation scheme for mitigating spatial interference in practical HBF MU-MIMO networks. IABA solves the network sum throughput optimization via either a distributed or a centralized BPL allocation using dedicated CSI reference signals for candidate BPL monitoring. We present a comprehensive study of practical multi-cell mm-wave networks and demonstrate that HBF MU-MIMO without interference-aware BPL allocation experiences strong residual interference which limits the achievable network performance. Our results show that IABA offers significant performance gains over the default interferenceagnostic 5G-NR BPL allocation, and even allows HBF MU-MIMO to outperform the fully digital MU-MIMO baseline, by facilitating allocation of secondary BPLs other than the strongest BPL found during initial access. We further demonstrate the scalability of IABA with increased gNB antennas and densification for beyond-5G mm-wave networks.

Authors 4

1. Aleksandar Ichkov Aachen Institute for Networked Systems (INETS)

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems, RWTH Aachen University, Aachen, Germany

   Institute for Networked Systems at RWTH Aachen University, Aachen, Germany

2. Alexander Wietfeld Aachen Institute for Networked Systems (INETS)

   Technical University of Munich · RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems, RWTH Aachen University, Aachen, Germany

   Chair of Communication Networks at Technical University of Munich, Munich, Germany

   Institute for Networked Systems at RWTH Aachen University, Aachen, Germany

3. Marina Petrova Aachen Institute for Networked Systems and the Mobile Communications and Computing Teaching and Research Area

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems and the Mobile Communications and Computing Teaching and Research Area, RWTH Aachen University, Aachen, Germany

   Institute for Networked Systems and the Mobile Communications and Computing Teaching and Research Area at RWTH Aachen University, Aachen, Germany

4. Ljiljana Simić Aachen Institute for Networked Systems (INETS)

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems, RWTH Aachen University, Aachen, Germany

   Institute for Networked Systems at RWTH Aachen University, Aachen, Germany