Online Control of Traffic Split and Distributed Cell Group State Decisions for Multi-Connectivity in 5G and Beyond

Sunghoon Jung, Saewoong Bahk

Abstract: The emergence of new radios (NRs) including mmWave in 5G necessitates multi-connectivity to enable a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">robust</i> control plane as well as a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">faster</i> user plane to satisfy stringent mobile service requirements. In multi-connectivity, a mobile user equipment (UE) communicates with multiple base stations simultaneously, where each base station provides a cell group as radio resources to the UE. In this paper, we design an online control policy for downlink transmission in a multi-connectivity environment. Our control policy aims to split incoming traffic of packets into multiple base stations and jointly determine the state of each cell group. Our design constraints include periodical traffic splitting and distributed cell group state decisions subject to limited cell group decision opportunities. Designing control policies that meet these constraints poses significant challenges. By applying the Lyapunov optimization method, we develop a joint control algorithm for real-time traffic splitting and cell group state decisions to satisfy the imposed constraints. Our proposed algorithms are robust and simple enough to be implemented in a real network. We confirm through analysis and simulation that our algorithm achieves optimal performance and outperforms other competitive schemes in terms of the balance between power consumption and queue length.