Improving QoS and Management in Multi-Hop Wireless Networks

To meet the ever-increasing demand for wireless access to the Internet, multi-hop wireless networks have been introduced to provide fast, easy, and inexpensive wireless last-mile connectivity. By using “free ” wireless links, multi-hop networks can easily be deployed to cover large areas or are being adopted for many emerging applications, including home networks and city-wide wireless clouds. On the other hand, a recent measurement study has shown that due to heterogeneous and changing environments, multi-hop networks of-ten provide poor Quality-of-Service (QoS) and/or incur high management costs. Network users often experience fluctuation in end-to-end performance, caused by intermittent in-terferences or new obstacles. Furthermore, network engineers need to put considerable management efforts into identifying the interference sources or manually reconfiguring the network settings or the physical locations of nodes. This thesis proposes novel system-level monitoring and adaptation techniques, through which multi-hop wireless networks can significantly improve user-perceived QoS and re-duce human-involved network management efforts. First, it focuses on the link-quality fluctuation problem and presents distributed link-quality monitoring techniques that allo