SynthCAT: Synthesizing Cellular Association Traces with Fusion of Model-Based and Data-Driven Approaches

The scarcity of publicly available cellular association traces hinders user location-based research and various data-driven services, highlighting the importance of data synthesis in this field. In this paper, we investigate the cellular association trace synthesis (CATS) problem, aiming to generate diverse and realistic cellular association traces based on road segment-based trajectories and corresponding departure times. To substantiate our research, we first gather substantial data, including road segment-based trajectories, base station (BS) distribution, and ground truths of cellular association traces. We then perform systematic data analysis to reveal technical challenges such as disparity in geographic spaces, complex and dynamic BS handover, and poor performance of single-dimension approaches. To address these challenges, we propose SynthCAT, a novel scheme that fuses model-based and data-driven approaches. Specifically, SynthCAT includes: i) A model-based coarse-grained cellular association trace generation component, encompassing GPS reference generation, weighted historical average time generation, Bayesian decision, and time mapping modules. This component establishes a unified GPS space to map road and BS spaces, generates initial time information, synthesizes coarse-grained spatial cellular association traces by following explicit BS handover rules, and maps the corresponding arrival time for each trace point; ii) A fine-grained cellular association trace generation component, which combines model-based and data-driven approaches. This employs a two-stage Autoencoder Generative Adversarial Network (AEGAN) to refine cellular association traces based on the coarse-grained ones. Extensive field experiments validate the efficacy of SynthCAT in terms of trace similarity to ground truths and its efficiency in supporting practical downstream applications.