  Indoor localization plays a vital role in applications such as emergency
response, warehouse management, and augmented reality experiences. By deploying
machine learning (ML) based indoor localization frameworks on their mobile
devices, users can localize themselves in a variety of indoor and subterranean
environments. However, achieving accurate indoor localization can be
challenging due to heterogeneity in the hardware and software stacks of mobile
devices, which can result in inconsistent and inaccurate location estimates.
Traditional ML models also heavily rely on initial training data, making them
vulnerable to degradation in performance with dynamic changes across indoor
environments. To address the challenges due to device heterogeneity and lack of
adaptivity, we propose a novel embedded ML framework called FedHIL. Our
framework combines indoor localization and federated learning (FL) to improve
indoor localization accuracy in device-heterogeneous environments while also
preserving user data privacy. FedHIL integrates a domain-specific selective
weight adjustment approach to preserve the ML model's performance for indoor
localization during FL, even in the presence of extremely noisy data.
Experimental evaluations in diverse real-world indoor environments and with
heterogeneous mobile devices show that FedHIL outperforms state-of-the-art FL
and non-FL indoor localization frameworks. FedHIL is able to achieve 1.62x
better localization accuracy on average than the best performing FL-based
indoor localization framework from prior work.
