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IEEE Transactions on Information Theory 01/2011; 57(1):95-100. · 3.01 Impact Factor
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ABSTRACT: The broadcast phase (downlink transmission) of the two-way relay network is studied in the source coding and joint source-channel coding settings. The rates needed for reliable communication are characterised for a number of special cases including: small distortions, deterministic distortion measures, and jointly Gaussian sources with quadratic distortion measures. The broadcast problem is also studied with common-reconstruction decoding constraints, and the rates needed for reliable communication are characterised for all discrete memoryless sources and per-letter distortion measures.
11/2010;
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ABSTRACT: The focus is on noise-free half-duplex line networks with two sources where the first node and either the second node or the second-last node in the cascade act as sources. In both cases, we establish the capacity region of rates at which both sources can transmit independent information to a common sink. The achievability scheme presented for the first case is constructive while the achievability scheme for the second case is based on a random coding argument. Comment: Proceedings of the IEEE International Symposium on Information Theory, Austin, TX, USA, June 12 - 18, 2010
06/2010;
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Bell Labs Technical Journal. 01/2010; 14:149-162.
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Gerhard Kramer
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ABSTRACT: Recent coding strategies for deterministic and noisy relay networks are related to the pipelining of block Markov encoding. For deterministic networks, it is shown that pipelined encoding improves encoding delay, as opposed to end-to-end delay. For noisy networks, it is observed that decode-and-forward exhibits good rate scaling when the signal-to-noise ratio (SNR) increases. Comment: 6 pages, 2 figures, 1 table; Presented at the 2009 Workshop on Network Coding, Theory, and Applications, EPFL, Lausanne, Switzerland, June 15-16, 2009
11/2009;
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ABSTRACT: The Marton-Gelfand-Pinsker inner bound on the capacity region of broadcast channels was extended by Han-Costa to include arbitrarily correlated sources where the capacity region is replaced by an admissible source region. The main arguments of Han-Costa are correct but unfortunately the authors overlooked an inequality in their derivation. The corrected region is presented and the absence of the omitted inequality is shown to sometimes admit sources that are not admissible.
02/2009;
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Bell Labs Technical Journal. 01/2009; 14:157-166.
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ABSTRACT: The instantaneous optical Kerr effect in optical fibers is a nonlinear phenomenon that can impose limits on the ability of fiber-optic communication systems to transport information. We present here a conservative estimate of the "fiber channel" capacity in an optically routed network. We show that the fiber capacity per unit bandwidth for a given distance significantly exceeds current record experimental demonstrations.
Physical Review Letters 11/2008; 101(16):163901. · 7.37 Impact Factor
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ABSTRACT: Inner and outer bounds are established on the capacity region of two-sender, two-receiver interference channels (IC) where one transmitter knows both messages. The transmitter with this extra message knowledge is referred to as being cognitive. The inner bound is based on strategies that generalise prior work, and includes rate-splitting, Gel'fand-Pinsker (GP) coding and cooperative transmission. A general outer bound is based on the Nair-El Gamal outer bound for broadcast channels (BCs). A simpler bound is presented for the case in which one of the decoders can decode both messages. The bounds are evaluated and compared for Gaussian channels. Copyright © 2008 John Wiley & Sons, Ltd.
European Transactions on Telecommunications 05/2008; 19(4):405 - 420. · 0.45 Impact Factor
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CoRR. 01/2008; abs/0805.4053.
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Bell Labs Technical Journal. 01/2008; 13:129-146.
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Bell Labs Technical Journal. 01/2008; 13:147-161.
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EURASIP J. Wireless Comm. and Networking. 01/2008; 2008.
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ABSTRACT: A rate distortion problem is solved that is motivated by a quantum data compression problem. The goal is to send information about a source string x so that a receiver can construct a second string y for which the joint empirical probability distribution of x and y is close to some desired distribution. The problem differs from the usual rate distortion problems in that one must consider both remote sources and distortion functions that are not averages of per-letter distortion functions
IEEE Transactions on Information Theory 03/2007; · 3.01 Impact Factor
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Gerhard Kramer
Foundations and Trends® in Communications and Information Theory 01/2007; 4:265-444.
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Foundations and Trends in Networking. 01/2006; 1.
