Empirical Study of Mobility Support in Millimeter-Wave Outdoor Urban Deployments

Abstract

The use of high-gain directional communications is key to enable the capacity enhancement of millimeter-wave (mm-wave) spectrum for 5G-and-beyond networks. However, this entails extensive beam management to continuously track the mobile user to maintain precise transmitter (TX)/receiver (RX) beam alignment. Detailed characterization of mm-wave link opportunities in real-world urban environments and corresponding beam management requirements, are key to addressing the great challenge of mobility support for mm-wave urban deployments. In this paper, we present the results of our large-scale outdoor urban mm-wave measurements using phased antenna arrays, where we collected received signal strength data over fine-grained 3D TX/RX orientations for 78 spatially-dense RX positions in three sub-regions in Aachen, totaling over 421,000 individual measurements. Our results show 2–8 spatial link opportunities per RX position, where only up to 40% of all RX orientations result in a feasible mm-wave connection. Our results suggest that the beam management burden would fall heavily on the mobile user-side, and be moderate on the TX-side, for a typical walk in vicinity of the serving cell. For example, the required TX-side beam steering from one RX position to the next to maintain a minimum data rate of 1 Gbps is less than 12° (twice the half power-beamwidth), but up to 88° at the RX-side. Therefore, obtaining spatially-dense and fine-grained angular propagation data is a critical input for the design and evaluation of mm-wave beam management protocols.

Authors 4

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

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems (iNETS), RWTH Aachen University, Aachen, Germany

2. Immanuel Gehring Aachen Institute for Networked Systems (INETS)

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems (iNETS), RWTH Aachen University, Aachen, Germany

3. Petri Mähönen Aachen Institute for Networked Systems (INETS)

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems (iNETS), RWTH Aachen University, Aachen, Germany

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

   RWTH Aachen University

   Affiliation as printed

   Institute for Networked Systems (iNETS), RWTH Aachen University, Aachen, Germany