Towards Deriving Analytical Model for Optimal Cell Overlap to Reduce Handover Signaling

The conventional network dimensioning and optimization approaches prioritize coverage and capacity as the most vital components. However, handover signaling overhead has emerged as a critical concern in the emerging cellular networks. This is particularly evident with the proliferation of network densification leading to a higher number of handovers. Hence, an optimal cell overlap is vital to ensure retainability and service continuity for the ever-growing fraction of mobile users and the expected cell densification. It is also crucial because the unprecedented signaling overhead can clog both the core network and air interface. To address this challenge, this paper presents an analytical model built on the control data separation architecture (CDSA) to quantify the handover signaling overhead as a function of cell overlap, user speed and cell density. We first compute probabilities for handover failures and successes and model the handover signaling overhead as a Markov chain. Numerical results demonstrate that for a given cell density and user velocity, a suitable cell overlap yields substantial reductions in handover signaling by improving handover success rate. The proposed model has the potential to become an integral element in the network planning process for emerging cellular networks.