The paper is devoted to the analysis of problems appearing in optimisation and improvement of the powerbandwidth efficiency of digital communication feedback systems (FCS). There is shown that unlike digital systems, adaptive FCS with the analogue forward transmission allow full optimisation and derivation of optimal transmission-reception algorithm approaching their efficiency to the Shannon b...

I N the 50 years since Shannon determined the capacity of ergodic channels, the construction of capacity-approaching coding schemes has been the supreme goal of coding research. Finally today, we know of practical codes and decoding algorithms that can closely approach the channel capacity of some classical memoryless channels. It is a remarkable fact motivating this special issue that all know...

The storage of information in biological memory relies on changes in neuronal circuits, termed plasticity. Synaptic contributions to plasticity, which are an important component, may be divided into changes in existing synapses, and changes in interneuronal connectivity through formation and elimination of synapses. Interneuronal connectivity changes may be further divided into contributions as...

We call two permutations of the first n naturals colliding if they map at least one number to consecutive naturals. We give bounds for the exponential asymptotics of the largest cardinality of any set of pairwise colliding permutations of [n]. We relate this problem to the determination of the Shannon capacity of an infinite graph and initiate the study of analogous problems for infinite graphs...

We study the statistics of optical data transmission in a noisy nonlinear fiber channel with a weak dispersion management and zero average dispersion. Applying analytical expressions for the output probability density functions both for a nonlinear channel and for a linear channel with additive and multiplicative noise we calculate in a closed form a lower bound estimate on the Shannon capacity...

For the additive white Gaussian noise channel with average codeword power constraint, sparse superposition codes are developed. Both encoding and decoding are computationally feasible. The codewords are linear combinations of subsets of vectors from a given dictionary, with the possible messages indexed by the choice of subset. An adaptive successive decoder is developed, with which communicati...

The optimization between the processing gain and the theoretically achievable average channel capacity per user (in the Shannon sense) of a constant total system's allocated bandwidth hybrid direct sequence/fast frequency hopping codedivision multiple-access (DS/FFH-CDMA) cellular system, when operating in a Rayleigh fading environment, is presented. ... Pagination p 902-910 Subject Engineering...

Starting from Shannon theory of information, we present the case of producing information in the form of multisets, and encoding information using multisets. We compute the entropy of a multiset information source by constructing an equientropic string source (with interdependent symbols), and we compare this with a string information source with independent symbols. We then study the encoder a...

Much progress has been made on decoding algorithms for error-correcting codes in the last decade. In this article, we give an introduction to some fundamental results on iterative, message-passing algorithms for low-density parity check codes. For certain important stochastic channels, this line of work has enabled getting very close to Shannon capacity with algorithms that are extremely effici...

Shannon’s theory, although it is sometimes referred to as a “theory of information,” is nothing of the sort. It is a theory of coding and of channel capacity. To achieve his desired aim, Shannon concentrated on the average amount of data generated by a source or transmitted through a channel. What that data represented was irrelevant to his purposes. Indeed, whereas it is possible to average nu...