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Dissertation Defense

Characterization and Optimization of Resource Utilization for Cellular Networks

Feng Qian

Cellular data networks have experienced significant growth in the recent years particularly due to the emergence of smartphones. Despite its popularity, there remain two major challenges associated with cellular carriers and their customers: carriers operate under severe resource constraints, while mobile applications often utilize radio channels and consume handset energy inefficiently. My dissertation is dedicated to address both challenges, aiming at providing practical, effective, and efficient methods to monitor and to reduce the resource utilization and bandwidth consumption in cellular networks. Specifically, from carriers' perspective, we performed the first measurement study to understand the state-of-the-art of resource utilization for a commercial cellular network, and revealed that fundamental limitation of the current resource management policy is treating all traffic according to the same resource management policy globally configured for all users. On mobile applications' side, we developed a novel data analysis framework called ARO (mobile Application Resource Optimizer), the first tool that exposes the interaction between mobile applications and the radio resource management policy, to reveal inefficient resource usage due to a lack of transparency in the lower-layer protocol behavior. ARO revealed that many popular applications built by professional developers have significant resource utilization inefficiencies that are previously unknown. Motivated by the observations from both sides, we further proposed a novel resource management framework that enables the cooperation between handsets and the network to allow adaptive resource release, therefore better balancing the key tradeoffs in cellular networks. We also investigated the problem of reducing the bandwidth consumption in cellular networks by performing the first network-wide study of HTTP caching on smartphones due to its popularity. Our findings suggest that for web caching, there exists a huge gap between the protocol specification and the protocol implementation on today's mobile devices, leading to significant amount of redundant network traffic.

Sponsored by

Zhuoqing Morley Mao