End-to-End Millimeter-Wave Network Performance and Mobility Management Overhead in Urban Cellular Deployments with Realistic Pedestrian Traffic and Blockages

Abstract

Millimeter-wave (mm-wave) frequencies are seen as the new frontier in enabling high capacity for 5G-and-beyond cellular networks. However, spatio-temporal variations of the mm-wave channel impose significant challenges for high rate error-free communication, due to increased propagation loss and blockage susceptibility. In this paper, we analyze the end-to-end mobile user performance and the extent of mobility management overhead in the presence of dynamic pedestrian blockages. We use site-specific propagation data obtained via high resolution ray-tracing and realistic pedestrian traffic to implement site-specific user mobility and pedestrian blockage models, and integrate these in an extensive ns-3 framework to study the end-to-end mobile user performance. Our results show that the number of mm-wave mobility management events -- beam tracking, beam steering and handover -- strongly depends on the pedestrian walk nature and number of blockage events, i.e. the primary mm-wave serving link can be blocked for up to 36% of a walk duration. These frequent short-term pedestrian blockages can lead to TCP throughput degradation of up to 35% and TCP round-trip-time spikes of over 1 s, compared to the achievable network performance when pedestrian blockages are not considered, assuming mobility management with up-to-date CSI. We also show that stale CSI -- arising from delay in periodic beam training procedures -- results in more frequent and sub-optimal mobility management decisions and an additional TCP throughput degradation of up to 30%, compared to the achievable TCP throughput assuming mobility management with up-to-date CSI.

Authors 3

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

   RWTH Aachen University

   Affiliation as printed

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

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

   RWTH Aachen University

   Affiliation as printed

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

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

   RWTH Aachen University

   Affiliation as printed

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