We've all got to the edge of the wifi coverage, but the idea of coverage produces a network problem, the Hidden Node Problem. Dr Steve Bagley explains. https://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com/