Dmitri V. Truhachev

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Asymptotic iterative decoding performance is analyzed for several classes of iteratively decodable codes when the block length of the codes N and the number of iterations I go to infinity. Three classes of codes are considered. These are Gallager's regular low-density parity-check (LDPC) codes, Tanner's generalized LDPC (GLDPC) codes, and the turbo codes(More)
Demodulation in a random multiple access channel is considered where the signals are chosen uniformly randomly with unit energy. It is shown that by lifting (replicating) the graph of this system and randomizing the graph connections, a simple iterative cancellation demodulator achieves the same performance as an optimal symbol-by-symbol detector of the(More)
A new class of binary iteratively decodable codes with good decoding performance is presented. These codes, called braided block codes (BBCs), operate on continuous data streams and are constructed by interconnection of two component block codes. BBCs can be considered as convolutional (or sliding) version of either Elias' product codes or expander codes.(More)
An ensemble of (J, K) -regular low-density parity-check (LDPC) convolutional codes is introduced and existence-type lower bounds on the minimum distance d<sub>L</sub>, of code segments of finite length L and on the free distance d<sub>free</sub> are derived. For sufficiently large constraint lengths v, the distances are shown to grow linearly with v and the(More)
We consider a signaling format where information is modulated via a superposition of independent data streams. Each data stream is formed by replication and permutation of encoded information bits. The relations between data bits and modulation symbols transmitted over the channel can be represented in the form of a sparse graph. The modulated streams are(More)
A portable 4 × 4 multiple-input multiple-output (MIMO) testbed that is based on field programmable gate arrays (FPGAs) and which operates in the 902–928MHz industrial, scientific, and medical (ISM) band has been developed by the High Capacity Digital Communications (HCDC) Laboratory at the University of Alberta. We present a description of the HCDC testbed(More)
Analytic expressions for the exact bit error probabilities of rate R=1/2, memory m=2 convolutional encoders are derived for a maximum-likelihood (ML) decoder and transmission over the binary-symmetric channel (BSC). The resulting expressions are rational functions of the crossover probability of the BSC. In addition to classical nonsystematic encoders(More)
We analyze a class of high performance, low decoding data-flow codes suitable for high bit-rate optical-fiber communication systems. A spatially-coupled split-component ensemble is defined, encompassing the most representative codes in this class, staircase codes and braided block codes. Our definition preserves two important properties of this class of(More)