Network Measurement and Systems for Resource-Constrained Environments

摘要

As mobile and wireless networks become the dominant user access technology in well-connected regions, they face an explosion in demand for high-bandwidth Internet and cellular connectivity. Additionally, wireless, both cellular and broadband, has become the de facto access technology at the Internet's frontier in developing contexts and other resource-limited environments due to underlying economic factors. In order for wireless and mobile networks to maintain pace with demand, and achieve global connectivity, we must empirically study existing networks and use those findings to inform new system designs across the telecommunications hierarchy.;Before we can build and deploy networks at the Internet's frontier to bring the next billion users online, we must understand the unique challenges currently faced by networks in resource-limited environments. In this thesis, we measure and characterize real-world operational networks, both cellular and wireless broadband, so that we can later use insights gleaned from this analysis to inform system designs aimed at ameliorating the performance inadequacies we witness. Our work includes a one-of-a-kind glimpse into cellular infrastructure performance in an operational refugee camp from the user's perspective. Our analysis shows that the networks we study often provide users with diminished performance due to factors such as oversubscription and relatively small backhaul links.;Whereas network systems are often designed for highly-connected, resource-rich contexts, this thesis strives to consider holistically (i.e. across multiple tiers of the telecommunications hierarchy) the challenges to providing robust connectivity in limited settings. Based on our comprehensive analysis of real-world conditions, we produce cellular and broadband systems aimed at bridging the technological gap that exists for people in challenging network environments. While the focus of our work is in specific environments, developing world contexts share many similarities, enabling the generalization of the systems we create to other resource-limited scenarios.