1,690 research outputs found
From Physics to Information Theory and Back
Quantum information theory has given rise to a renewed interest in, and a new perspective on, the old issue of understanding the ways in which quantum mechanics differs from classical mechanics. The task of distinguishing between quantum and classical theory is facilitated by neutral frameworks that embrace both classical and quantum theory. In this paper, I discuss two approaches to this endeavour, the algebraic approach, and the convex set approach, with an eye to the strengths of each, and the relations between the two. I end with a discussion of one particular model, the toy theory devised by Rob Spekkens, which, with minor modifications, fits neatly within the convex sets framework, and which displays in an elegant manner some of the similarities and differences between classical and quantum theories. The conclusion suggested by this investigation is that Schrödinger was right to find the essential difference between classical and quantum theory in their handling of composite systems, though Schrödinger's contention that it is entanglement that is the distinctive feature of quantum mechanics needs to be modified
A Simplified Min-Sum Decoding Algorithm for Non-Binary LDPC Codes
Non-binary low-density parity-check codes are robust to various channel
impairments. However, based on the existing decoding algorithms, the decoder
implementations are expensive because of their excessive computational
complexity and memory usage. Based on the combinatorial optimization, we
present an approximation method for the check node processing. The simulation
results demonstrate that our scheme has small performance loss over the
additive white Gaussian noise channel and independent Rayleigh fading channel.
Furthermore, the proposed reduced-complexity realization provides significant
savings on hardware, so it yields a good performance-complexity tradeoff and
can be efficiently implemented.Comment: Partially presented in ICNC 2012, International Conference on
Computing, Networking and Communications. Accepted by IEEE Transactions on
Communication
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