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This article introduces a novel communication paradigm for the unsourced, uncoordinated Gaussian multiple access problem. The major components of the envisioned framework are as follows. The encoded bits of every message are partitioned…

Information Theory · Computer Science 2020-11-23 Asit Pradhan , Vamsi Amalladinne , Avinash Vem , Krishna R. Narayanan , Jean-Francois Chamberland

For the additive white Gaussian noise channel with average codeword power constraint, sparse superposition codes are developed. These codes are based on the statistical high-dimensional regression framework. The paper [IEEE Trans. Inform.…

Information Theory · Computer Science 2012-07-11 Antony Joseph , Andrew Barron

A closed-form analytical expression is derived for the limiting empirical squared singular value density of a spreading (signature) matrix corresponding to sparse low-density code-domain (LDCD) non-orthogonal multiple-access (NOMA) with…

Information Theory · Computer Science 2017-05-10 Ori Shental , Benjamin M. Zaidel , Shlomo Shamai

An improved inference method for densely connected systems is presented. The approach is based on passing condensed messages between variables, representing macroscopic averages of microscopic messages. We extend previous work that showed…

Information Theory · Computer Science 2009-11-11 Juan P. Neirotti , David Saad

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

Sparse code multiple access (SCMA) is a promising technique for the enabling of massive connectivity in future machine-type communication networks, but it suffers from a limited diversity order which is a bottleneck for significant…

Information Theory · Computer Science 2023-08-28 Qu Luo , Zilong Liu , Gaojie Chen , Pei Xiao

We consider the detection of correlated information sources in the ubiquitous Code-Division Multiple-Access (CDMA) scheme. We propose a message-passing based scheme for detecting correlated sources directly, with no need for source coding.…

Information Theory · Computer Science 2010-03-24 Hadar Efraim , Nadav Yacov , Ori Shental , Ido Kanter

The performance of a CDMA based wireless system is largely dependent on the characteristics of pseudo-random spreading codes. The spreading codes should be carefully chosen to ensure highest possible peak value of auto-correlation function…

Information Theory · Computer Science 2012-06-12 Deepak Kedia

In this paper, we obtain a family of lower bounds for the sum capacity of Code Division Multiple Access (CDMA) channels assuming binary inputs and binary signature codes in the presence of additive noise with an arbitrary distribution. The…

Information Theory · Computer Science 2016-11-18 K. Alishahi , F. Marvasti , V. Aref , P. Pad

We consider communication over the Gaussian multiple-access channel in the regime where the number of users grows linearly with the codelength. In this regime, schemes based on sparse superposition coding can achieve a near-optimal tradeoff…

Information Theory · Computer Science 2025-06-04 Xiaoqi Liu , Kuan Hsieh , Ramji Venkataramanan

This paper studies the affine frequency division multiplexing (AFDM)-empowered sparse code multiple access (SCMA) system, referred to as AFDM-SCMA, for supporting massive connectivity in high-mobility environments. First, by placing the…

Information Theory · Computer Science 2024-06-12 Qu Luo , Pei Xiao , Zilong Liu , Ziwei Wan , Thomos Nikolaos , Zhen Gao , Ziming He

Sparse code multiple access (SCMA) is one of the most promising methods among all the non-orthogonal multiple access techniques in the future 5G communication. Compared with some other non-orthogonal multiple access techniques such as low…

Signal Processing · Electrical Eng. & Systems 2020-02-28 Fan Wei , Wen Chen

Sparse regression codes (SPARCs) are a class of codes that encode information through the superposition of columns of a randomised coding matrix. The combination with an outer non-binary low density parity check (NB-LDPC) code was recently…

Information Theory · Computer Science 2025-09-23 Alexander Fengler , Burak Çakmak , Giuseppe Caire

In this paper, we propose a learning approach for sparse code multiple access (SCMA) signal detection by using a deep neural network via unfolding the procedure of message passing algorithm (MPA). The MPA can be converted to a sparsely…

Information Theory · Computer Science 2018-08-27 Chao Lu , Wei Xu , Hong Shen , Hua Zhang , Xiaohu You

We take an information theoretic perspective on a classical sparse-sampling noisy linear model and present an analytical expression for the mutual information, which plays central role in a variety of communications/processing problems.…

Information Theory · Computer Science 2014-03-25 Wasim Huleihel , Neri Merhav , Shlomo Shamai

We address the problem of recovering a sparse signal observed by a resource constrained wireless sensor network under channel fading. Sparse random matrices are exploited to reduce the communication cost in forwarding information to a…

Information Theory · Computer Science 2015-04-16 Thakshila Wimalajeewa , Pramod K. Varshney

Asymptotic spectral distribution (ASD) of the crosscorrelation matrix is investigated for a random spreading short/long-code asynchronous direct sequence-code division multiple access (DS-CDMA) system. The discrete-time decision statistics…

Information Theory · Computer Science 2008-10-06 Chien-Hwa Hwang

Non-orthogonal multiple access (NOMA) is a promising technology which meets the demands of massive connectivity in future wireless networks. Sparse code multiple access (SCMA) is a popular code-domain NOMA technique. The effectiveness of…

Information Theory · Computer Science 2021-02-16 Kuntal Deka , Minerva Priyadarsini , Sanjeev Sharma , Baltasar Beferull-Lozano

Sparse coding refers to the pursuit of the sparsest representation of a signal in a typically overcomplete dictionary. From a Bayesian perspective, sparse coding provides a Maximum a Posteriori (MAP) estimate of the unknown vector under a…

Signal Processing · Electrical Eng. & Systems 2019-09-04 Dror Simon , Jeremias Sulam , Yaniv Romano , Yue M. Lu , Michael Elad

In this letter, a novel variation of sparse code multiple access (SCMA), called codeword position index based SCMA (CPI-SCMA), is proposed. In this scheme, the information is transmitted not only by the codewords in M point SCMA codebook,…

Signal Processing · Electrical Eng. & Systems 2018-11-12 Ke Lai , Lei Wen , Jing Lei , Gaojie Chen , Pei Xiao , Amine Maaref