Hidden Terminal Detection in Wide-Area 802.11 Wireless Networks

Abstract

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.