Speaker: Dr. Erran Li, Bell Labs Title: Making Cellular Networks Scalable and Flexible through Design-in-the-Large Date/time: 3:30-4:30pm Wednesday July 24 Location: 402 in the CS building Abstract: The rapid penetration of smart phones has put tremendous stress on cellular data networks. To understand the fundamental limitations of current cellular network architecture, I will first summarize my work on scalable network monitoring primitives and root cause analysis of performance problems. This work became a key part of the Alcatel-Lucent Wireless Network Guardian 9900 product. Our measurement study reveals that our mobile user experiences are hampered by the lack of access bandwidth at radio access networks and the inflexibility of cellular core networks. I will then address the two key problems through the principle of design-in-the-large. (1) To scale access bandwidth at radio access networks, I will present the design and prototype of Argos, a base station architecture that employs an unprecedented number of antennas simultaneously to serve a smaller number of mobile devices in the same band of frequencies. Both analysis and early experimental results suggest this design can lead to orders of magnitude increase in both spectral and energy efficiency. (2) To enable flexible provisioning of fine-grained policies at cellular core networks, I will summarize the design and prototype of SoftCell, a scalable software-defined cellular core network architecture. SoftCell achieves scalability through asymmetric edge design and selective multi-dimensional aggregation in the data plane and switch offloading in the control plane. Evaluations based on real LTE network traces show that a SoftCell controller can handle a network of thousands of base stations. This is joint work with collaborators at Princeton, Rice, Yale, and Bell Labs.