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Motivated by the set-antiset method for codes over permutations under the infinity norm, we study anticodes under this metric. For half of the parameter range we classify all the optimal anticodes, which is equivalent to finding the maximum permanent of certain (0, 1)-matrices. For the rest of the cases we show constraints on the structure of optimal anticodes.
We generalize the Wyner-Ziv source coding problem with side-information at the decoder to the case where the encoder is required to be able to compute the decoder's reconstruction sequence with some fidelity. This requirement limits the extent to which the reconstruction sequence can depend on the side-information, which is not available to the encoder. For finite-alphabet memoryless sources and single-letter...
We consider the problem of characterizing network capacity in the presence of adversarial errors on network links, focusing in particular on the effect of low-capacity feedback links across network cuts. We give a new outer bound as well as a new achievable strategy, and show a family of networks where the inner and outer bounds coincide.
Stability and convergence properties of stochastic approximation algorithms are analyzed when the noise includes a long range dependent component (modeled by a fractional Brownian motion) and a heavy tailed component (modeled by a symmetric stable process), in addition to the usual `martingale noise'. This is motivated by the emergent applications in communications. The proofs are based on comparing...
Some ideas are presented how methods from information theory might be applied to logistics, more exactly to RFID security problems. Identification codes might be useful in a nosiy environment. Network coding could help in encryption and authentification.
Many modern wireless data networks employ Carrier Sense Multiple Access (CSMA) for efficient medium access. The p-persistent CSMA protocol is an analytically tractable version of CSMA that has been used successfully to model practical medium access protocols such as the IEEE 802.11 Distributed Coordination Function (DCF). We present a closed-form expression to characterize the access probabilities...
This talk intends to bring out the following ideas: Understanding decoding power is important for design of relevant codes at short distances. Just as we have models for channel to understand transmit power, we need models of decoding implementation to understand decoding power. Node model: total power diverges to infinity as Pe → 0. Optimal transmit power bounded away from Shannon limit. Wire model:...
We consider the problem of minimizing the cost of cooperative data exchange between a group of wireless clients. In this problem, a group of clients needs to exchange a set of packets over a shared lossless broadcast channel. Each client initially holds a subset of packets and needs to obtain the packets held by other clients. At each round, one of the clients can broadcast its packets or a combination...
Recent works on multi-user transmission techniques have shown that the linear growth of capacity in single user MIMO system can be translated to the multi-user MIMO scenario as well. In this paper, we propose a method pursuing performance gain of vector perturbation in multi-user downlink channels. Instead of exploiting the maximum available mobile users for communication, we employ small part of...
Compared to other soft-decision decoding algorithms of Reed-Solomon (RS) codes, the low-complexity Chase (LCC) algorithm can achieve better performance-complexity tradeoff. In order to reduce the complexity of the LCC decoding, the re-encoding and coordinate transformation techniques can be applied for high-rate codes. In this case, to recover a codeword for an (n, k) RS code, an erasure decoding...
A new approach to analog-to-digital conversion is proposed which combines unstable analog filters with digital Kalman filtering. The proposed approach subsumes sigma-delta converters, on which it offers a new perspective.
We consider a discrete memoryless channel between two users and a destination in half-duplex mode implemented by time division. Each transmission block of length n is divided into 3 time slots with variable durations. During the first two time slots, each user alternatively transmits and receives, while during the last time slot, they both transmit to the destination. Even though within each time...
We consider the zero-error capacity of deletion channels. Specifically, we consider the setting where we choose a codebook C consisting of strings of n bits, and our model of the channel corresponds to an adversary who may delete up to pn of these bits for a constant p. Our goal is to decode correctly without error regardless of the actions of the adversary. We consider what values of p allow non-zero...
Theoretical analysis has long indicated that feedback improves the error exponent but not the capacity of memoryless Gaussian channels. Chen et al. demonstrated that a modified incremental redundancy scheme can use noiseless feedback to help short convolutional codes deliver the bit-error-rate performance of a long blocklength turbo code, but with much lower latency. This paper presents a code-independent...
We study the impact of time-correlated arrivals on the performance of backpressure policy for stochastic network control. The arrival process considered in this work is fairly general in the sense that it may exhibit short/long-range dependence depending on the asymptotic shape of the autocorrelation function. In this paper, we show that that the backpressure policy stabilizes the network whenever...
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