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We study a problem motivated by cognitive radio in which the primary is a packet system that employs ARQ feedback. A secondary system is allowed to transmit in the same frequency band provided it ensures that the primary attains a specified target rate. That is, the secondary has a certain "interference budget". The crux of the problem is that the secondary(More)
The utility of limited feedback for coding over an individual sequence of discrete memoryless channels is investigated. This study complements recent results showing how limited or noisy feedback can boost the reliability of communication. A strategy with fixed input distribution <i>P</i> is given that asymptotically achieves rates arbitrarily close to the(More)
Alice and Bob want to share a secret key and to communicate an independent message, both of which they desire to be kept secret from an eavesdropper Eve. This problem of secret communication and secret-key generation when two resources are available-correlated sources at Alice, Bob, and Eve, and a noisy broadcast channel from Alice to Bob and Eve which is(More)
This report presents two algorithms for sensor networks that save the energy used when sensors communicate. The first is Information Driven Sensor Querying (IDSQ). This technique uses a utility measure, such as the Mahalanobis distance or mutual information, to limit the number of sensors that need to communicate. The second technique is Distributed Source(More)
Alice and Bob want to share a secret key and to communicate an independent message, both of which they desire to be kept secret from an eavesdropper Eve. We study this problem of secret communication and secret key generation when two resources are available - correlated sources at Alice, Bob, and Eve, and a noisy broadcast channel from Alice to Bob and(More)
A generalization of the additive Gaussian two-way channel to <i>M</i> users is considered. Such channels contain implicit feedback in the sense that the channel output signals observed by the different encoders are correlated. While the benefits of feedback are shown to be negligible at high SNR, for moderate SNR, feedback can play a significant role in(More)
Alice and Bob want to share a secret key and to communicate an independent message, both of which they desire to be kept secret from an eavesdropper Eve. We study this problem of secret communication and secret key generation when two resources are available – correlated sources at Alice, Bob, and Eve, and a noisy broadcast channel from Alice to Bob and Eve(More)