Privacy-Preserving Federated Learning for Coverage Prediction

In 5G cellular networks, Machine Learning (ML) can be exploited to predict if a user equipment (UE) is in the coverage area of a neighbouring cell. This could improve crucial cellular network functionalities, such as handovers, interference mitigation and carrier aggregation. In this paper, we study the enhancement of UEs’ privacy in a Differentially Private-Federated Learning (DP-FL) scheme relying on the sampled Gaussian mechanism, assuming honest-but-curious threat model. With this technique, the UE’s privacy is protected by perturbing the averaged updates conducted at the server; also, the usage of client subsampling results in an amplified privacy and a reduced overhead in terms of communication. We demonstrate that the models trained with our approach can achieve better privacy-utility tradeoff than previous works can. In addition, we conduct membership inference attack to study the factors that impact the empirical privacy protection to the training data. We make a novel observation that suggests that for coverage prediction task, larger datasets and/or smaller ML models would provide stronger empirical privacy protection to training data. Beyond the task we consider, this observation could be a useful insight for dataset curation or model architecture selection in other domains and warrants additional investigation.