A class of algebraically structured quasi-cyclic (QC) low-density parity-check (LDPC) codes and their convolutional counterparts is presented. The QC are described by sparse matrices comprised blocks circulant matrices. representation allows for practical graph-based iterative message-passing decoding. Based on the algebraic structure, bounds girth minimum distance found, several possible encoding techniques described. performance LDPC block compares favorably with that randomly constructed...

This paper proposes a network coding approach to cooperative diversity featuring the algebraic superposition of channel codes over finite field. The scenario under consideration is one in which two ldquopartnersrdquo - node A and B cooperate transmitting information single destination; each partner transmits both locally generated relayed that originated at other partner. key observation already knows A's (because it B) can exploit knowledge when decoding local information. leads an encoding...

The goal of this paper is to establish which practical routing schemes for wireless networks are most suitable power-limited and bandwidth-limited communication regimes. We regard channel state information (CSI) at the receiver point-to-point capacity-achieving codes additive white Gaussian noise (AWGN) as features, interference cancellation (IC) possible, but less practical, synchronous cooperation (CSI transmitters) impractical. consider a network with single source node, destination N-1...

An optical orthogonal code (OOC) is a collection of binary sequences with good auto- and cross-correlation properties; they were defined by Salehi others as means obtaining code-division multiple access on networks. Up to now, all work OOCs have assumed that the constraint placed autocorrelation are same. We consider-codes for which two constraints not equal. Specifically we develop bounds size such demonstrate constriction techniques building them. The results significant increase in...

We consider the problem of reliably transmitting CELP-encoded speech over noisy communication channels. Our objective is to design efficient coding/decoding schemes for transmission CELP line spectral parameters (LSPs) very begin by quantifying amount "residual redundancy" inherent in LSPs Federal Standard 1016 CELP. This done modeling as first- and second-order Markov chains. Two models LSP generation are proposed; first model characterizes intraframe correlation exhibited LSPs, while...

This paper describes techniques to decompose LT codes (a class of rateless erasure-correcting codes) into distributed (DLT) codes. DLT can be used independently encode data from multiple sources in a network such way that, when the DLT-encoded packets are combined at common relay, resulting bit stream (called modified (MLT) code) has degree distribution approximating that an code, with simulations indicating comparable performance. In essence, designed so final stage encoding for erasure...

Since the discovery of turbo codes 20 years ago and subsequent rediscovery low-density parity check a few later, field channel coding has experienced number major advances. Until that time, code designers were usually happy with performance came within decibels Shannon Limit, primarily due to implementation complexity constraints, whereas new techniques now allow small fraction decibel capacity modest encoding decoding complexity. Due these significant improvements, standards in applications...

We introduce a binary additive communication channel with memory. The noise process of the is generated according to contagion model G. Polya (1923); our motivation empirical observation Stapper et al. (1980) that defects in semiconductor memories are well described by distributions derived from Polya's urn scheme. resulting stationary but not ergodic, and it has many interesting properties. first derive maximum likelihood (ML) decoding algorithm for channel; turns out ML equivalent received...

This paper proposes a new approach to channel code design for wireless network applications. The resulting nested codes can be decoded at different effective rates by receivers-rates that depend on the prior knowledge possessed each receiver; we say these have multiple interpretations. We identified several applications in networks where this property is useful. Specific constructions as well efficient soft and hard decision decoding algorithms are described. concept of with interpretations...

In systems that employ source coding, imperfect compression may leave some redundancy in the data at input to channel encoder. This paper presents a new method for exploiting via joint source-channel maximum posteriori (MAP) decoding. The technique be applied variable-length code conjunction with code; decoder uses residual remains after enhance robustness. proposed (applicable both memoryless and Markov sources) combines model, construct conventional Viterbi structure. Simulation results...

This paper presents some trellis codes that provide high coding gain to channels with slow, non frequency-selective Rayleigh fading. It is shown the use of two encoders in parallel-used specify in-phase and quadrature components transmitted signal-results greater minimum time diversity than conventional design which a single encoder used. Using this approach-which we label "I-Q TCM"-codes bandwidth efficiencies 1, 2, 3 bits/s/Hz are described for various constraint lengths. The performance...

We consider a wireless communication system with single source node, destination and multiple relay nodes placed equidistantly between them. limit our analysis to the case of coded TDMA multihop transmission, i.e., do not cooperate try access channel simultaneously. Given global constraint on bandwidth, we determine number hops that achieves desired end-to-end rate least total transmission power. Furthermore, examine how optimum changes when an delay is introduced using sphere-packing bound...

This paper compares the performance of convolutional codes to that LDPC block with identical decoding latencies. The algorithms considered are Viterbi algorithm and stack sequential for iterative message passing codes. It is shown that, at very low latencies, offer best performance, whereas high latencies dominate - offers over a range intermediate latency values. "crossover latencies" i.e., values which code/decoding selection changes identified variety code rates (1/2, 2/3, 3/4, 5/6)...

This paper describes the design and analysis of low-density parity-check (LDPC) codes over rings shows how these codes, when mapped onto appropriate signal constellations, can be used to effect bandwidth-efficient modulation. Specifically, LDPC are constructed integer /spl Zopf//sub m/ G/sub m//sup 2/ phase-shift keying (PSK)-type sets yield geometrically uniform space codes. identifies addresses issues that affect code performance. Examples 8/ 64/ 8-ary 64-ary at a spectral efficiency 1.5...

This paper presents a quantitative study of the benefits that mobile relays can provide to wireless infrastructure namely, extension base station coverage and enhancement connection throughput. The end user choose connect directly station, or, as an alternative, establish two-hop link using relay. Relay locations are modelled realizations two-dimensional Poisson process with random motion, such their availability forward messages received from or is analyzed. Two important performance...

Abstract NOTE: The first page of text has been automatically extracted and included below in lieu an abstract Main Menu Session 2253 A Multidisciplinary Course Sequence for First-Year Engineering Students Jay B. Brockman, Thomas E. Fuja, Stephen M. Batill University Notre Dame developed a new year engineering program, central to that program is two-course sequence entitled “Introduction Systems.” These courses use team-based, multidisciplinary projects introduce students the profession...

We consider maximum a posteriori (MAP) detection of binary asymmetric Markov source transmitted over channel. The MAP detector observes long (but finite) sequence channel outputs and determines the most probable sequence. In some cases, can be implemented by simple rules such as "believe what you see" rule or "guess zero (or one) regardless rule. provide necessary sufficient conditions under which this is true. When these are satisfied, exact bit error probability determined. examine in...

This paper presents a low-complexity interleaver design that facilitates the high throughput turbo decoding required for next generation wireless systems. Specifically, it addresses issues arise when several Log-MAP processors are used in parallel to improve throughput. In such decoder, memory access contentions occur more than one extrinsic value is be written or read from same block at time. These may avoided by designing contention- free (CF) interleavers incorporate hardware constraints...

For decoding low-density parity-check (LDPC) codes, the attenuated min-sum algorithm (AMSA) and offset (OMSA) can outperform conventional (MSA) at low signal-to-noise-ratios (SNRs), i.e., in "waterfall region" of bit error rate curve. This paper demonstrates that, for quantized decoders, MSA actually outperforms AMSA OMSA "error floor" region, that all three algorithms suffer from a relatively high floor. motivates introduction modified is designed to MSA, AMSA, across SNRs. The new based on...

This paper proposes a novel distributed encoding procedure to realize codes that resemble LT (rateless for erasure correction) in both structure and performance. For the case of two sources communicating with single sink via common relay, this technique separately encodes k/2 symbols information onto slightly more than k code at each source. These codewords are then selectively XOR-ed such result can be decoded by recover all symbols. It is shown that, four sink, use similar leads 50%...

In this paper, we study spatially coupled lowdensity parity-check (SC-LDPC) codes over finite fields GF(q), q ≥ 2, and develop design rules for q-ary SC-LDPC code ensembles based on their iterative belief propagation decoding thresholds, with particular emphasis low-latency windowed (WD). We consider transmission both the binary erasure channel (BEC) binary-input additive white Gaussian noise (BIAWGNC) present results a variety of (J, K)-regular constructed GF(q) using protographs....

This paper proposes a new approach to cooperative diversity based on the algebraic superposition of channel codes over finite field. The scenario under consideration is one in which two "partners" - Node A and B cooperate transmitting information single destination; each partner transmits both locally-generated relayed that originated at other partner. key observation already knows A's (previously sent from B) can exploit knowledge when decoding local information. leads an encoding scheme...

In this paper we study the iterative decoding threshold performance of non-binary spatially-coupled low-density parity-check (NB-SC-LDPC) code ensembles for both binary erasure channel (BEC) and binary-input additive white Gaussian noise (BIAWGNC), with particular emphasis on windowed (WD). We consider (2,4)-regular (3,6)-regular NB-SC-LDPC constructed using protographs compute their thresholds protograph versions NB density evolution extrinsic information transfer analysis. For these...

A class of convolutional codes called cross parity check (CPC) codes, which are useful for the protection data stored on magnetic tape, is described and analyzed. CPC first explained geometrically; their construction in terms constraining written onto a tape such way that when lines varying slope drawn across bits falling those sum to zero modulo two. This geometric interpretation then formalized by canonical matrices systematic generator computing constraint lengths. The distance properties...