HybridCell: Cellular connectivity on the fringes with demand-driven local cells

While cellular networks connect over 3.7 billion people worldwide, their availability and quality is not uniform across regions. Under-provisioned and overloaded networks lead to poor network performance and an aggravated user experience. To address this problem we propose HybridCell: a system that leverages locally-owned small-scale cellular networks to augment the operation of overloaded commercial networks. HybridCell is the first system to allow a user with their existing SIM card and mobile phone to seamlessly switch between commercial and local networks in order to maintain continuous connectivity. Hybrid-Cell accomplishes this by identifying poorly-performing networks and taking action to provide seamless cellular connectivity to end users. Using traces collected from observing the cellular infrastructure during our visit to the Za'atari refugee camp in Jordan, we demonstrate HybridCell's capability to detect and act upon commercial network overload, offering an alternate communication channel during times of congestion. We show that even in scenarios where provider networks deny calls due to overload, HybridCell is able to accommodate users and facilitate local calling.