The increasing need for high data-rate transmissions over time- or frequency-selective fading channels has drawn attention to modulation schemes with spectral efficiency such as QAM. With the aim of "diversity order" signal set we consider multidimensional rotated QAM constellations. Very diversity orders can be achieved and this results in an almost Gaussian performance channel, This scheme is essentially uncoded enables one trade system complexity, at no power bandwidth expense.

Recent work on lattices matched to the Rayleigh fading channel has shown how construct good signal constellations with high spectral efficiency. We present a new family of lattice constellations, based complex algebraic number fields, which have performance channels. Some these also reasonable packing density and thus may be used at same time over Gaussian channel. Conversely, we show that particular versions best packings (D/sub 4/, E/sub 6/, 8/, K/sub 12/, /spl Lambda//sub 16/, 24/),...

We present a framework for iterative multiuser joint decoding of code-division multiple-access (CDMA) signals, based on the factor-graph representation and sum-product algorithm. In this framework, known parallel serial, hard soft interference cancellation algorithms are derived in unified way. The asymptotic performance these limit large code block length can be rigorously analyzed by using density evolution. show that, random spreading large-system limit, evolution is considerably...

We propose a method for extracting an errorless secret key in continuous-variable quantum distribution protocol, which is based on Gaussian modulation of coherent states and homodyne detection. The crucial feature eight-dimensional reconciliation the algebraic properties octonions. Since protocol does not use any post-selection, it can be proven secure against arbitrary collective attacks by using well-established theorems optimality attacks. By this coding scheme with appropriate...

Reconciliation is an essential part of any secret-key agreement protocol and hence a Quantum Key Distribution (QKD) protocol, where two legitimate parties are given correlated data want to agree on common string in the presence adversary, while revealing minimum amount information. In this paper, we show that for discrete-variable QKD protocols, problem can be advantageously solved with Low Density Parity Check (LDPC) codes optimized BSC. particular, demonstrate our method leads significant...

We derive a low-complexity receiver scheme for joint multiuser decoding and parameter estimation of code division multiple access signals. The resulting processes the users serially iteratively makes use soft-in soft-out single-user decoders, soft interference cancellation expectation-maximization as main building blocks. Computer simulations show that proposed achieves near performance at very high channel load (number per chip) outperforms conventional schemes with similar complexity.

We build a class of pseudo-random error correcting codes, called generalized low density codes (GLD), from the intersection two interleaved block codes. GLD code performance approaches channel capacity limit and decoder is based on simple fast SISO (soft input-soft output) decoders smaller are special case Tanner generalization Gallager's LDPC It also proved by an ensemble argument that these asymptotically good in sense minimum distance criterion. The flexibility selecting parameters makes...

Soft output detection for signals transmitted on linear channels is investigated. A particular emphasis made signal multiple antenna channels. The a posteriori information at the detector evaluated from shifted spherical list of point candidates. centered maximum likelihood point, which has great advantage stabilizing size. Thus, sphere radius selected in order to control size and cope with boundaries finite constellation. Our new soft decoder then applied computation constrained channel...

We solve the problem of designing powerful low-density parity-check (LDPC) codes with iterative decoding for block-fading channel. first study case maximum-likelihood decoding, and show that design criterion is rather straightforward. Unfortunately, optimal constructions do not perform well under decoding. To overcome this limitation, we then introduce a new family full-diversity LDPC exhibit near-outage-limit performance all block-lengths. This competes multiplexed parallel turbo suitable...

We describe a soft feedback iterative decoding technique for bit-interleaved coded modulations (BICM) where the modulator uses multiple transmitting antennas and receiver employs space-time coherent detection with antennas. investigate bit error rate frame performance of this applied to two families error-control codes: simple nonrecursive binary convolutional codes parallel turbo based on recursive constituents. Two different types fading channels are considered: independent flat Rayleigh...

A quasi-static flat multiple-antenna channel is considered. We show how real multilevel modulation symbols can be detected via deep neural networks. multi-plateau sigmoid function introduced. Then, after showing the DNN architecture for detection, we propose a twin-network structure. Batch size and training statistics efficient learning are investigated. Near-Maximum-Likelihood performance with relatively reasonable number of parameters achieved.

We compare the performance of short-length linear binary codes on erasure channel and binary-input Gaussian channel. use a universal decoder that can decode any block code: Gaussian-elimination based Maximum-Likelihood probabilistic Ordered Statistics Decoder As such we not decoders. The word error rate versus parameter is found for LDPC, Reed-Muller, Polar, BCH at length 256 bits. outperform other in absence cyclic redundancy check. Under joint decoding, concatenation check makes all...

We describe a new family of integer lattices built from construction A and non-binary LDPC codes. An iterative message-passing algorithm suitable for decoding in high dimensions is proposed. This lattices, referred to as LDA follows the recent transition Euclidean codes their classical theory modern approach announced by pioneering work Loeliger (1997), Erez, Litsyn, Zamir (2004-2005). Besides excellent performance near capacity limit, lattice conceptually simpler than previously proposed...

In this paper, we consider the use of lattice codes over Eisenstein integers for implementing a compute and-forward protocol in wireless networks when channel state information is not available at transmitter. We extend compute-and-forward paradigm Nazer and Gastpar to decoding integer combinations transmitted messages relays by proving existence sequence pairs nested lattices which coarse good covering fine can achieve Poltyrev limit. Using result, show that both outage performance...

The space-time bit-interleaved coded modulation (ST-BICM) is an efficient technique to obtain high diversity and coding gain on a block-fading MIMO channel. Its maximum-likelihood (ML) performance computed under ideal interleaving conditions, which enables global optimization taking into account channel coding. Thanks upperbound derived from the Singleton bound, appropriate choice of time dimension possible, maximizes while minimizing complexity. Based analysis, optimized interleaver set...

We consider the use of lattice codes over Eisenstein integers for implementing a compute-and-forward protocol in wireless networks when channel state information is not available at transmitter. prove existence sequence infinite-dimensional nested lattices where coarse simultaneously good quantization and additive white Gaussian noise (AWGN) coding fine AWGN coding. Using this, we show that rates achievable with codebooks can be higher than those considered by Nazer Gastpar [1] some set...

We propose a rate 1/3 infinite-length irregular turbo code capable of achieving an error P/sub eb/=10/sup -5/ at signal-to-noise ratio E/sub b//N/sub 0/=-0.46 dB, which is distance 0.03 dB from Shannon capacity limit. Our derived by simple modification the original Berrou-Glavieux code.

A new joint detection method based on sphere packing lattice decoding is presented in this paper. The algorithm suitable for both synchronous and asynchronous multiple access direct-sequence code-division multiple-access (DS-CDMA) systems, it may jointly detect up to 64 users with a reasonable complexity. complexity independent of the modulation size large M-PAM or M-QAM constellations can be used. Furthermore, theoretical gain analysis performed which system performance derived from parameters.

We consider channel estimation in multiple-input multiple-output (MIMO) systems using iterative detection at the receiver. Space-time bit-interleaved coded modulation (BICM) and soft-input soft-output maximum a posteriori (MAP) symbol decoding are considered. Channel coefficients updated each iteration of detector semi-blind approach based on expectation maximization (EM) algorithm. first show that "classical" non-optimized EM implementation, as already proposed some previous works, gives...

We study Low-Density Parity-Check (LDPC) codes with iterative decoding on block-fading (BF) Relay Channels. consider two users that employ coded cooperation, a variant of decode-and-forward smaller outage probability than the latter. An analysis for discrete constellations shows full diversity can be achieved only when coding rate does not exceed maximum value depends level cooperation. derive new code structure by extending previously published full-diversity root-LDPC code, designed BF...

We address the problem of transmission information over AWGN channel using lattices. In particular, we will deal with previously introduced LDA lattices which are obtained by Construction A from LDPC codes finite field F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</inf> . show how to build a particular ensemble related bipartite graphs good expansion properties. investigate quality this family under lattice decoding and that random member...

In time entanglement-based quantum key distribution (TE-QKD), Alice and Bob extract the raw bits from arrival times of entangled photon pairs. Each pair can contribute to multiple depending on how precisely measure times. Thus, TE-QKD potentially increase secret rate compared typical QKD implementations, which up a bit per photon. Because entanglement, arrivals at Alice’s Bob’s detectors and, thus, their keys should be identical. However, practical suffer jitter errors. These errors cause...

Multidimensional binary mappings for bit-interleaved coded modulations (BICMs) on ergodic multiple-antenna channels with iterative decoding are presented. After derivation of a closed-form expression the pairwise error probability under ideal maximum-likelihood (ML) decoding, design criterion mapping optimization is established from ML performance ideally interleaved channel. It coincides figure merit derived genie condition when receiver converges to perfect priori information....

This work is a first attempt to analyze and understand the coding gain of full-diversity (MDS) low-density parity-check (LDPC) codes. A diversity population evolution derived. The steady-state distribution energy coefficients found. Based on this new analysis, we show LDPC codes with improved performance. Finally, describe family graph where all variable nodes, including parity achieve full after large number decoding iterations. Full-diversity MDS are not only useful for digital data...