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Families of "asymptotically regular" LDPC block code ensembles can be formed by terminating (J,K)-regular protograph-based LDPC convolutional codes. By varying the termination length, we obtain a large selection of LDPC block code ensembles…

Information Theory · Computer Science 2016-11-15 David G. M. Mitchell , Roxana Smarandache , Michael Lentmaier , Daniel J. Costello

Practical distributed quantum computing and error correction require quantum networks with high-qubit-rate, high-fidelity, and low-reconfiguration-latency. Unfortunately, current approaches are limited by fundamental constraints:…

In wireless communication systems, there are many stages for signal transmission. Among them, mapping and demapping convert a sequence of bits into a sequence of complex numbers and vice versa. This operation is performed by a system of…

Information Theory · Computer Science 2023-03-07 Daniil Yudakov , Dmitrii Kolosov , Evgeny Bobrov

Precoding for multiple-input, multiple-output (MIMO) antenna systems is considered with perfect channel knowledge available at both the transmitter and the receiver. For 2 transmit antennas and QAM constellations, an approximately optimal…

Information Theory · Computer Science 2015-03-17 K. Pavan Srinath , B. Sundar Rajan

For a high-rate case, it is difficult to randomly construct good low-density parity-check (LDPC) codes of short and moderate lengths because their Tanner graphs are prone to making short cycles. Also, the existing high-rate quasi-cyclic…

Information Theory · Computer Science 2016-11-18 Hosung Park , Seokbeom Hong , Jong-Seon No , Dong-Joon Shin

Quasi-complementary sequence sets (QCSSs) have attracted sustained research interests for simultaneously supporting more active users in multi-carrier code-division multiple-access (MC-CDMA) systems compared to complete complementary codes…

Information Theory · Computer Science 2024-01-12 Palash Sarkar , Chunlei Li , Sudhan Majhi , Zilong Liu

Over-the-air computation (OAC) enables low-latency aggregation over multiple-access channels (MACs) by exploiting the superposition property of the wireless medium to compute functions efficiently in distributed networks. A critical but…

Signal Processing · Electrical Eng. & Systems 2026-02-25 Saeed Razavikia , Deniz Gündüz , Carlo Fischione

This paper shows an optimal spreading sequence in the Weyl sequence class, which is similar to the set of the Oppermann sequences for asynchronous CDMA systems. Sequences in Weyl sequence class have the desired property that the order of…

Information Theory · Computer Science 2019-01-21 Hirofumi Tsuda , Ken Umeno

Quantum communication typically involves a linear chain of repeater stations, each capable of reliable local quantum computation and connected to their nearest neighbors by unreliable communication links. The communication rate in existing…

We propose index codes, based on multidimensional QAM constellations, for the Gaussian broadcast channel, where every receiver demands all the messages from the source. The efficiency with which an index code exploits receiver side…

Information Theory · Computer Science 2016-11-18 Lakshmi Natarajan , Yi Hong , Emanuele Viterbo

A simple and general definition of quasi cyclic low density parity check (QC LDPC) codes which are constructed based on circulant permutation matrices (CPM) is proposed. As an special case of this definition, we first represent one type of…

Information Theory · Computer Science 2017-01-24 A. Tasdighi , M. R. Sadeghi

In dynamically varying optical wireless communication (OWC) links, conventional quadrature amplitude modulation (QAM) in optical orthogonal frequency-division multiplexing (OFDM) requires frequent channel estimation and equalization,…

Optics · Physics 2026-03-19 Tian Cao , Ping Wang , Tianfeng Wu , Kaile Wang , Jian Song

This report describes the design and proposal of a wireless link capable of broadcasting at 1 Gbps. For this application, isotropic antennas, 256 QAM modulation, and BER level less than 1e-5, without using error correction coding, were…

Signal Processing · Electrical Eng. & Systems 2023-06-21 David Noel

Golay sequences are well suited for the use as codewords in orthogonal frequency-division multiplexing (OFDM), since their peak-to-mean envelope power ratio (PMEPR) in q-ary phase-shift keying (PSK) modulation is at most 2. It is known that…

Information Theory · Computer Science 2007-07-16 Kai-Uwe Schmidt

In this paper, we first derive the generic algebraic structure of a Quasi-Orthogonal STBC (QO-STBC). Next we propose Group-Constrained Linear Transformation (GCLT) as a means to optimize the diversity and coding gains of a QO-STBC with…

Information Theory · Computer Science 2008-06-23 Chau Yuen , Yong Liang Guan , Tjeng Thiang Tjhung

Spectrally efficient multi-antenna wireless communication systems are a key challenge as service demands continue to increase. At the same time, powering up radio access networks is facing environmental and regulation limitations. In order…

Quantum Mechanics (QM) predicts the correlation between measurements performed in remote regions of a spatially spread entangled state to be higher than allowed by the intuitive concepts of Locality and Realism (LR). This high correlation…

Quantum Physics · Physics 2019-04-17 Alejandro Hnilo , Mónica Agüero

Code-division multiple-access (CDMA) has the potential to support traffic sources with a wide range of quality of service (QoS) requirements. The traffic carrying capacity of CDMA channels under QoS constraints (such as delay guarantee) is,…

Networking and Internet Architecture · Computer Science 2011-05-03 Kashif Mahmood , Mikko Vehkaperä , Yuming Jiang

We have proposed a quasi-large random-sequence (QLRS) CDMA where K users access a point through a common channel with spectral spreading factor N. Each bit is extended by a temporal spreading factor B and hopped on a BN-chip random sequence…

Information Theory · Computer Science 2008-02-26 Yi Sun

This paper conceives a novel sparse code multiple access (SCMA) codebook design which is motivated by the strong need for providing ultra-low decoding complexity and good error performance in downlink Internet-of-things (IoT) networks, in…

Information Theory · Computer Science 2022-09-13 Qu Luo , Zilong Liu , Gaojie Chen , Pei Xiao , Yi Ma , Amine Maaref