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Sparse code multiple access (SCMA) is an emerging paradigm for efficient enabling of massive connectivity in future machine-type communications (MTC). In this letter, we conceive the uplink transmissions of the low-density parity check…

Information Theory · Computer Science 2022-02-14 Lingyun Chai , Zilong Liu , Pei Xiao , Amine Maaref , Lin Bai

Sparse signatures have been proposed for the CDMA uplink to reduce multi-user detection complexity, but they have not yet been fully exploited for its downlink counterpart. In this work, we propose a Multi-Carrier CDMA (MC-CDMA) downlink…

Information Theory · Computer Science 2017-02-10 Min Li , Chunshan Liu , Stephen V. Hanly

Sparse code multiple access (SCMA) is a class of non-orthogonal multiple access (NOMA) that is proposed to support uplink machine-type communication services. In an SCMA system, designing multidimensional constellation plays an important…

Information Theory · Computer Science 2018-10-30 Monirosharieh Vameghestahbanati , Ian Marsland , Ramy H. Gohary , Halim Yanikomeroglu

Orthogonal Frequency Division Multiple Access (OFDMA) as well as other orthogonal multiple access techniques fail to achieve the system capacity limit in the uplink due to the exclusivity in resource allocation. This issue is more prominent…

Information Theory · Computer Science 2017-05-12 Mohammed Al-Imari , Pei Xiao , Muhammad Ali Imran , Rahim Tafazolli

In this paper we propose resource allocation algorithm for uplink sparse code multiple access (SCMA) networks to maximize the energy efficiency (EE). Due to the joint optimization of factor graph matrix and power allocation matrix, the EE…

Signal Processing · Electrical Eng. & Systems 2020-04-22 Samira Jaber , Wen Chen , Kunlun Wang , Jun Li

In this paper, we study resource allocation and adaptive modulation in SC-FDMA which is adopted as the multiple access scheme for the uplink in the 3GPP-LTE standard. A sum-utility maximization (SUmax), and a joint adaptive modulation and…

Information Theory · Computer Science 2015-03-19 Ayaz Ahmad , Mohamad Assaad

In this paper, we study the uplink channel throughput performance of a proposed novel multiple-antenna hybrid-domain non-orthogonal multiple access (MA-HD-NOMA) scheme. This scheme combines the conventional sparse code multiple access…

Information Theory · Computer Science 2020-12-01 Animesh Yadav , Chen Quan , Pramod K. Varshney , H. Vincent Poor

In this paper, the performance and system complexity of the candidate multiple access (MA) techniques for the next generation of cellular systems, namely, non-orthogonal multiple access (NOMA) (in this paper, we consider power domain MA as…

Information Theory · Computer Science 2017-02-07 Mohammad. Moltafet , Nader. Mokari , Mohammad R. Javan , Paiez. Azmi

Sparse code multiple access (SCMA) is the most concerning scheme among non-orthogonal multiple access (NOMA) technologies for 5G wireless communication new interface. Another efficient technique in 5G aimed to improve spectral efficiency…

Information Theory · Computer Science 2022-09-22 Yukai Liu , Wen Chen

Space-Division Multiple Access (SDMA) utilizes linear precoding to separate users in the spatial domain and relies on fully treating any residual multi-user interference as noise. Non-Orthogonal Multiple Access (NOMA) uses linearly precoded…

Information Theory · Computer Science 2018-11-22 Yijie Mao , Bruno Clerckx , Victor O. K. Li

Uplink grant-free non-orthogonal multiple access (NOMA) is a promising technology for massive connectivity with low latency and high energy efficiency. In code-domain NOMA schemes, the requirements boil down to the design of codebooks that…

Combinatorics · Mathematics 2025-12-22 Chunlei Li , Constanza Riera , Palash Sarkar , Pantelimon Stanica

In this paper, a novel uncoordinated random access (URA) protocol is presented to address the pressing demand for massive connectivity with low access latency in future massive machine type communication (mMTC) scenarios. The proposed URA…

Signal Processing · Electrical Eng. & Systems 2025-10-28 Pengyu Gao , Qu Luo , Jing Zhu , Gaojie Chen , Pei Xiao , Chuan Heng Foh

With the advent of the 6G mobile communication network era, the existing non-orthogonal multiple-access (NOMA) technology faces the challenge of high successive interference in multi-user scenarios, which limits its ability to support more…

Emerging Technologies · Computer Science 2025-02-25 Zihan Li , Youzhi Li , Chenyu Liuand Yuhao Lian

Non-orthogonal multiple access (NOMA) systems have the potential to deliver higher system throughput, compared to contemporary orthogonal multiple access techniques. For a linearly precoded multiple-input multiple-output (MISO) system, we…

Information Theory · Computer Science 2015-12-08 Muhammad Fainan Hanif , Zhiguo Ding , Tharmalingam Ratnarajah , George K. Karagiannidis

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

This paper proposes, for the first time, a hybrid multiple access framework that integrates the principles of rate-splitting (RS) and sparse code multiple access (SCMA) in an SISO downlink scenario. The proposed scheme, termed RS-SCMA,…

Signal Processing · Electrical Eng. & Systems 2026-01-29 Minerva Priyadarsini , Zilong Liu , Kuntal Deka , Sujit Kumar Sahoo , Sanjeev Sharma

This paper studies a downlink system that combines orthogonal-time-frequency-space (OTFS) modulation and sparse code multiple access (SCMA) to support massive connectivity in high-mobility environments. We propose a cross-domain receiver…

Information Theory · Computer Science 2023-01-04 Haifeng Wen , Weijie Yuan , Zilong Liu , Shuangyang Li

This paper studies enhanced dense code multiple access (DCMA) system design for downlink transmission over the Nakagami-$m$ fading channels. By studying the DCMA pairwise error probability (PEP) in a Nakagami-$m$ channel, a novel design…

Information Theory · Computer Science 2023-09-08 Yiming Gui , Zilong Liu , Lisu Yu , Chunlei Li , Pingzhi Fan

In this paper, a new approach for multiple access (MA) in fifth generation (5G) of cellular networks called power domain sparse code multiple access (PSMA) is proposed. In PSMA, we adopt both the power domain and the code domain to transmit…

Information Theory · Computer Science 2017-06-21 Nader Mokari , Mohammad. R Javan , Mohammad Moltafet , Hamid Saeedi , Hossein Pishro-Nik

Spatial modulation (SM)-sparse code multiple access (SCMA) systems provide high spectral efficiency (SE) at the expense of using a high number of transmit antennas. To overcome this drawback, this letter proposes a novel SM-SCM A system…

Signal Processing · Electrical Eng. & Systems 2020-06-16 Ibrahim Al-Nahhal , Octavia A. Dobre , Ertugrul Basar , Salama Ikki