1,499 research outputs found
Golden Space-Time Trellis Coded Modulation
In this paper, we present a concatenated coding scheme for a high rate
multiple-input multiple-output (MIMO) system over slow fading
channels. The inner code is the Golden code \cite{Golden05} and the outer code
is a trellis code. Set partitioning of the Golden code is designed specifically
to increase the minimum determinant. The branches of the outer trellis code are
labeled with these partitions. Viterbi algorithm is applied for trellis
decoding. In order to compute the branch metrics a lattice sphere decoder is
used. The general framework for code optimization is given. The performance of
the proposed concatenated scheme is evaluated by simulation. It is shown that
the proposed scheme achieves significant performance gains over uncoded Golden
code.Comment: 33 pages, 13 figure
Linear tail-biting trellises: Characteristic generators and the BCJR-construction
We investigate the constructions of tail-biting trellises for linear block
codes introduced by Koetter/Vardy (2003) and Nori/Shankar (2006). For a given
code we will define the sets of characteristic generators more generally than
by Koetter/Vardy and we will investigate how the choice of characteristic
generators affects the set of resulting product trellises, called KV-trellises.
Furthermore, we will show that each KV-trellis is a BCJR-trellis, defined in a
slightly stronger sense than by Nori/Shankar, and that the latter are always
non-mergeable. Finally, we will address a duality conjecture of Koetter/Vardy
by making use of a dualization technique of BCJR-trellises and prove the
conjecture for minimal trellises.Comment: 28 page
Cyclic division algebras: a tool for space-time coding
Multiple antennas at both the transmitter and receiver ends of a wireless digital transmission channel may increase both data rate and reliability. Reliable high rate transmission over such channels can only be achieved through Space–Time coding. Rank and determinant code design criteria have been proposed to enhance diversity and coding gain. The special case of full-diversity criterion requires that the difference of any two distinct codewords has full rank.
Extensive work has been done on Space–Time coding, aiming at
finding fully diverse codes with high rate. Division algebras have been proposed as a new tool for constructing Space–Time codes, since they are non-commutative algebras that naturally yield linear fully diverse codes. Their algebraic properties can thus be further exploited to
improve the design of good codes.
The aim of this work is to provide a tutorial introduction to the algebraic tools involved in the design of codes based on cyclic division algebras. The different design criteria involved will be illustrated, including the constellation shaping, the information lossless property, the non-vanishing determinant property, and the diversity multiplexing trade-off. The final target is to give the complete mathematical background underlying the construction of the Golden code and the other Perfect Space–Time block codes
Recent advances in coding theory for near error-free communications
Channel and source coding theories are discussed. The following subject areas are covered: large constraint length convolutional codes (the Galileo code); decoder design (the big Viterbi decoder); Voyager's and Galileo's data compression scheme; current research in data compression for images; neural networks for soft decoding; neural networks for source decoding; finite-state codes; and fractals for data compression
Decoding Schemes for Foliated Sparse Quantum Error Correcting Codes
Foliated quantum codes are a resource for fault-tolerant measurement-based
quantum error correction for quantum repeaters and for quantum computation.
They represent a general approach to integrating a range of possible quantum
error correcting codes into larger fault-tolerant networks. Here we present an
efficient heuristic decoding scheme for foliated quantum codes, based on
message passing between primal and dual code 'sheets'. We test this decoder on
two different families of sparse quantum error correcting code: turbo codes and
bicycle codes, and show reasonably high numerical performance thresholds. We
also present a construction schedule for building such code states.Comment: 23 pages, 15 figures, accepted for publication in Phys. Rev.
Vector quantization
During the past ten years Vector Quantization (VQ) has developed from a theoretical possibility promised by Shannon's source coding theorems into a powerful and competitive technique for speech and image coding and compression at medium to low bit rates. In this survey, the basic ideas behind the design of vector quantizers are sketched and some comments made on the state-of-the-art and current research efforts
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