2026/08/03 by Kiichi Tokuyama
Computer Science · #cs.NI
arxiv created 2026/08/03 · arxiv updated 2026/08/04
Mobility robustness optimization (MRO) requires an appropriate selection of handover (HO) parameters such as the time-to-trigger (TTT) and the offset margin to balance HO failures and ping-pong HOs. Existing stochastic-geometry-based analyses for MRO often characterize the target base station (BS) by assuming that its angular position is uniformly distributed over a feasible region. However, this assumption does not explicitly capture the spatial distribution of the target BS dynamically selected as a user equipment (UE) moves through the network. In this paper, we develop a stochastic-geometry-based analytical framework for MRO in sub-6 GHz cellular networks. We first derive the distribution of the HO triggering time and the spatial distribution of the dynamically selected target BS under straight-line UE mobility. Based on these distributions, we formulate too-late HO and ping-pong HO events as mutually exclusive mobility events and analytically derive their probabilities. Numerical results validate the analytical expressions and demonstrate that explicitly characterizing the target BS distribution has a non-negligible impact on the evaluated HO performance. Furthermore, the derived framework quantifies the tradeoff between too-late HO and ping-pong HO probabilities with respect to the TTT and enables the identification of a TTT value that minimizes their sum.