Hidden Terminal Detection in Wide-Area 802.11 Wireless Networks

The hidden terminal problem is an important issue in wireless networks based on the CSMA medium access control scheme. Hidden terminals pose a complex challenge to network operators trying to identify the underlying cause of performance issues. This thesis describes new methods for the detection and measurement of the hidden terminal problem in wireless networks based on commodity hardware and software platforms. These new methods allow network operators to identify areas of a network where hidden terminals are likely to exist; detect instances of the hidden terminal problem occurring; and estimate the total impact hidden terminals are having on the performance of the network. A new framework for measurement of wireless networks is described which provides a new approach to wireless measurement on Linux based wireless routers. The new framework is used to implement the methods and they are deployed across an operational commercial wireless network and are shown to be useful

Analysis of the Serengeti Broadband Network

Internet access is intermittent and very expensive in remoteareas in the developing world. The access is still mainly pro-vided via satellite links to other continents and, although thetransition to terrestrial networks has started, it will taketime to reach the under-served areas. To understand thelocal needs and traffic patterns in rural areas, we have an-alyzed Internet web traffic logs captured over a year froma municipal network deployed in remote areas in Tanzania.The web traffic logs analysis was complemented by user sur-veys on their actual usage.Our analysis reveals that popularity of social networkingand news websites increases over time.We have noticed manyother contents such as advertisements which we consider notrelevant to developing regions but consume the little band-width they have. Based on the insights gained from theanalysis, we have provided recommendations on how to op-timize the little bandwidth available. Further, we have de-ployed some of the recommendations in the current system.QC 2011100