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EEcient paging procedures help minimize the amount of bandwidth expended in locating a mobile unit. Given a probability distribution on user location, it is shown that the optimal paging strategy which minimizes the expected number of locations polled EL] is to query each location sequentially in order of decreasing probability. However, since sequential(More)
Motivated by the emergence of programmable radios, we seek to understand a new class of communication system where pairs of transmitters and receivers can adapt their modulation/demodulation method in the presence of interference to achieve better performance. Using signal to interference ratio as a metric and a general signal space approach, we present a(More)
Interference avoidance is a class of adaptive modulation techniques in which, with feedback from the receiver, a transmitting radio is instructed to vary its waveform so as to maximize the signal-to-interference plus noise-ratio. For an ensemble of users connected to a single receiver interference avoidance methods have been thoroughly analyzed. This thesis(More)
We consider a wireless system with base stations which collaborate, and derive bounds on sum capacity and total squared correlation for uniform channels between users and bases. The correspondence also investigates structural properties which must be satisfied by user transmit covariance matrices at the optimal sum capacity/total squared correlation (TSC)(More)
It is well known that if a stochastic service system (such as a cellular network) is shared by users with diierent characteristics (such as diiering handoo rates or call holding times), the overall system performance can be improved by denial of service requests even when the excess capacity exists. Such selective denial of service based on system state is(More)
We discuss file delivery issues for a new approach to inexpensive, high rate wireless data called Infostations. As opposed to ubiquitous coverage, infostations offer geographically intermittent coverage at high speed (1Mbps to 1Gbps) since data, as compared to voice, can often tolerate significant delay. The infostations paradigm flips the usual "(More)
Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995-2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on(More)
The process of nding a unit in a mobile communications system is called paging and requires the use of limited network resources. Although it is understood how to minimize the use of network resources and satisfy delay constraints when paging a single unit, optimal policies for paging multiple units are diicult to derive. Here we adapt single unit polling(More)