Omar Bakr

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We study the running time of distributed algorithms deployed in a widely distributed setting over the Internet using TCP. We consider a simple primitive that corresponds to a <i>communication round</i> in which every host sends information to every other host; this primitive occurs in numerous distributed algorithms. We experiment with four algorithms that(More)
— This paper presents a practical method for using multi-antenna radios to cancel interference in cognitive radio systems. Under this method, secondary radio transmitters use beamforming techniques to find antenna weights that place nulls at the primary receivers, and secondary radio receivers use adaptive techniques to decode in the presence of(More)
Although mobile phone usage has proliferated in urban areas of developing countries, many rural or poor users remain completely unconnected, particularly in Africa. In this paper, we advocate an alternative " voice message mostly " mobile phone architecture to reach the next billion users. Using initial analyses of mobile phone usage and rural power data,(More)
— We consider the problem of secure wireless communication in the presence of an eavesdropper when the transmitter has multiple antennas, using a variation of the recently proposed artificial noise technique. Under this technique, the transmitter sends a pseudo-noise jamming signal to selectively degrade the link to the eavesdropper without affecting the(More)
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