On the Analysis and Optimization of Fast Conditional Handover with Hand Blockage for Mobility

TL;DR

This paper investigates the performance of fast conditional handover (FCHO) in 5G systems with multi-panel user equipment, demonstrating significant mobility improvements and proposing resource optimization techniques to balance performance and signaling overhead.

Contribution

It introduces FCHO as an enhancement over traditional CHO, analyzes its resource reservation challenges, and proposes optimization methods to improve efficiency.

Findings

FCHO reduces mobility failures by up to 19.3% at high speeds.

Resource reservation optimization decreases signaling overhead.

FCHO offers performance gains with manageable resource trade-offs.

Abstract

Although frequency range 2 (FR2) systems are an essential part of 5G-Advanced and future 3GPP releases, the mobility performance of multi-panel user equipment (MPUE) with hand blockage is still an area open for research and standardization. In this article, a comprehensive study on the mobility performance of MPUE with hand blockage is performed for conditional handover (CHO) and its potential enhancement denoted by fast conditional handover (FCHO). In contrast to CHO, in FCHO the MPUE can reuse earlier target cell preparations after each handover to autonomously execute subsequent handovers. This saves both the signaling overhead associated with the reconfiguration and re-preparation of target cells after each handover and reduces mobility failures. Results have shown that FCHO offers considerable mobility performance gains as compared to CHO for different hand blockage cases that are dependent on the hand position around the MPUE. For the worst-case hand blockage scenario, it is seen that mobility failures reduce by 10.5% and 19.3% for the 60 km/h and 120 km/h mobility scenarios, respectively. This gain comes at the expense of reserving the handover resources of an MPUE for a longer time given that the target cell configurations are not necessarily released after each handover. In this article, the longer resource reservation problem in FCHO is analysed and three different resource reservation optimization techniques are introduced. Results have shown that these optimization techniques not only reduce the resource reservation time but also significantly reduce the signaling overhead at the possible expense of a tolerable degradation in mobility performance.