Distinguished Lecturer Series
Distinguished lecturer Hari Balakrishnan- Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science- presents her lecture Increasing Throughput by Increasing Concurrency (and Interference) in Wireless Networks.
Wireless will soon become the dominant mode of network access in the world. The performance of wireless networks in practice, however, is often disappointing, and is likely to worsen with increasing demand. Wireless networks are challenging because channel propagation is hard to model and predict, channel quality and behavior vary with time, and whether a transmission can be received correctly depends both on external conditions (such as node separation, obstacles, and reflections from nearby objects) and on concurrent transmissions by other nodes in the network. To cope, wireless network designers view bit errors and packet collisions with trepidation and seek to reduce them; in so doing, they hide the vagaries of radio under abstractions that make them appear like wires, which are much more predictable.
In this talk, Balakrishnan's position is that this approach is the reason for disappointing performance in practice. He will argue that wireless networks should maximize concurrency at all costs, even (especially) if it means that bit error rates rise. He will defend this controversial position that higher bit error rates and packet collisions are not a bad thing. He'll do so by showing that, with some modifications to the physical layer, higher layer designs can be far more optimistic and opportunistic in their transmissions, realizing huge throughput gains.
Bio: Hari Balakrishnan is a Professor of Computer Science and Engineering at M.I.T., having been there since Fall 1998 when he received his PhD from U.C. Berkeley. His research is in the area of networked computer systems, spanning wireless and sensor networks, network architecture and security, overlay and peer-to-peer networks, and data management systems. In addition to several widely cited papers, systems developed as part of his research (such as the Cricket location system, the RON and MONET overlay networks, the Chord DHT protocol, the rcc network checker, and the Aurora/Medusa stream processing system) are in production or commercial use.