An Efficient Uplink Multi-Connectivity Scheme for 5G mmWave Control Plane Applications

TL;DR

This paper proposes a novel uplink multi-connectivity scheme for 5G mmWave networks that improves robustness, speed, and stability of cell selection and handover by continuous channel monitoring and joint control with legacy bands.

Contribution

It introduces an uplink measurement system with a local coordinator for efficient multi-connectivity management in mmWave 5G networks, addressing link tracking and rapid reaction to blockages.

Findings

Uplink-based multi-connectivity outperforms traditional downlink schemes.

The proposed system enables faster and more stable handovers.

Efficient channel tracking improves robustness against mmWave link blockages.

Abstract

The millimeter wave (mmWave) frequencies offer the potential of orders of magnitude increases in capacity for next-generation cellular systems. However, links in mmWave networks are susceptible to blockage and may suffer from rapid variations in quality. Connectivity to multiple cells - at mmWave and/or traditional frequencies - is considered essential for robust communication. One of the challenges in supporting multi-connectivity in mmWaves is the requirement for the network to track the direction of each link in addition to its power and timing. To address this challenge, we implement a novel uplink measurement system that, with the joint help of a local coordinator operating in the legacy band, guarantees continuous monitoring of the channel propagation conditions and allows for the design of efficient control plane applications, including handover, beam tracking and initial access. We show that an uplink-based multi-connectivity approach enables less consuming, better performing, faster and more stable cell selection and scheduling decisions with respect to a traditional downlink-based standalone scheme. Moreover, we argue that the presented framework guarantees (i) efficient tracking of the user in the presence of the channel dynamics expected at mmWaves, and (ii) fast reaction to situations in which the primary propagation path is blocked or not available.