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Related papers: Zak-OTFS Based Coded Random Access for Uplink mMTC

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Wireless users with different characteristics will be expected to share spectrum in next generation communication networks. One of the great strengths of wireless networks based on Orthogonal Frequency Division Multiplexing (OFDM) is the…

Signal Processing · Electrical Eng. & Systems 2025-07-22 Imran Ali Khan , Saif Khan Mohammed , Ronny Hadani , Ananthanarayanan Chockalingam , Robert Calderbank

We consider the problem of uplink timing synchronization for Orthogonal Time Frequency Space (OTFS) modulation based systems where information is embedded in the delay-Doppler (DD) domain. For this, we propose a novel Random Access (RA)…

Information Theory · Computer Science 2021-04-08 Alok Kumar Sinha , Saif Khan Mohammed , P. Raviteja , Yi Hong , Emanuele Viterbo

Millimeter-wave (mmWave) communication offers vast bandwidth for next-generation wireless systems but faces severe path loss, Doppler effects, and hardware impairments. Orthogonal Time Frequency Space (OTFS) modulation has emerged as a…

Signal Processing · Electrical Eng. & Systems 2025-11-12 Sabarinath Ramachandran , Venkatesh Khammammetti , Prasanthi Maddala , Narayan Mandayam , Ivan Seskar , Robert Calderbank

Zak-transform based orthogonal time frequency space (Zak-OTFS) is a delay-Doppler (DD) domain modulation scheme in which the signal processing is carried out in the DD domain. The channel when viewed in the DD domain is predictable.…

Signal Processing · Electrical Eng. & Systems 2025-07-21 Sandesh Rao Mattu , Nishant Mehrotra , Robert Calderbank

Orthogonal Time Frequency Space (OTFS) is a framework for communications and active sensing that processes signals in the delay-Doppler (DD) domain. It is informed by 6G propagation environments, where Doppler spreads measured in kHz make…

Information Theory · Computer Science 2024-02-16 Beyza Dabak , Venkatesh Khammammetti , Saif Khan Mohammed , Robert Calderbank

4G/5G wireless standards use orthogonal frequency division multiplexing (OFDM) which is robust to frequency selectivity. Equalization is possible with a single tap filter, and low-complexity equalization makes OFDM an attractive physical…

Signal Processing · Electrical Eng. & Systems 2025-09-25 Sandesh Rao Mattu , Nishant Mehrotra , Saif Khan Mohammed , Venkatesh Khammammetti , Robert Calderbank

Space-time shift keying-aided orthogonal time frequency space modulation-based multiple access (STSK-OTFS-MA) is proposed for reliable uplink transmission in high-Doppler scenarios. As a beneficial feature of our STSK-OTFS-MA system, extra…

Information Theory · Computer Science 2023-09-08 Zeping Sui , Hongming Zhang , Sumei Sun , Lie-Liang Yang , Lajos Hanzo

Orthogonal time frequency space (OTFS) has emerged as the most sought-after modulation technique in a high mobility scenario. Sparse code multiple access (SCMA) is an attractive code-domain non-orthogonal multiple access (NOMA) technique.…

Signal Processing · Electrical Eng. & Systems 2021-07-22 Anna Thomas , Kuntal Deka , P. Raviteja , Sanjeev Sharma

Orthogonal Time Frequency Space (OTFS) is a $\text{2-D}$ modulation technique that has the potential to overcome the challenges faced by orthogonal frequency division multiplexing (OFDM) in high Doppler environments. The performance of OTFS…

Information Theory · Computer Science 2020-05-11 Kuntal Deka , Anna Thomas , Sanjeev Sharma

In the research of next-generation wireless communication technologies, orthogonal time frequency space (OTFS) modulation is emerging as a promising technique for high-speed mobile environments due to its superior efficiency and robustness…

Signal Processing · Electrical Eng. & Systems 2025-04-29 Yanfeng Hu , Dongming Wang , Xinjiang Xia , Jiamin Li , Pengcheng Zhu , Xiaohu You

In orthogonal time frequency space (OTFS) modulation, information-carrying symbols reside in the delay-Doppler (DD) domain. By operating in the DD domain, an appealing property for communication arises: time-frequency (TF) dispersive…

Signal Processing · Electrical Eng. & Systems 2022-12-07 Franz Lampel , Alex Alvarado , Frans M. J. Willems

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

We present an unsourced multiple access (UMAC) scheme tailored to high-mobility wireless channels. The proposed construction is based on orthogonal time frequency space (OTFS) modulation and sparse interleaver division multiple access…

Signal Processing · Electrical Eng. & Systems 2026-01-21 Davide Bergamasco , Federico Clazzer , Paolo Casari

Zak-Orthogonal Time Frequency Space (Zak-OTFS) modulation has been shown to achieve significantly better performance compared to the standardized Cyclic-Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM), in high delay/Doppler…

Orthogonal time frequency space (OTFS) modulation is a recent modulation scheme designed in the delay-Doppler domain. It has been shown to achieve superior performance compared to conventional multicarrier modulation schemes designed in the…

Information Theory · Computer Science 2019-02-12 G. D. Surabhi , Rose Mary Augustine , A. Chockalingam

The notion of a fast uplink grant is emerging as a promising solution for enabling massive machine type communications (MTCs) in the Internet of Things over cellular networks. By using the fast uplink grant, machine type devices (MTD) will…

Information Theory · Computer Science 2018-01-17 Samad Ali , Nandana Rajatheva , Walid Saad

We investigate a coded uplink non-orthogonal multiple access (NOMA) configuration in which groups of co-channel users are modulated in accordance with orthogonal time frequency space (OTFS). We take advantage of OTFS characteristics to…

Information Theory · Computer Science 2021-02-10 Yao Ge , Qinwen Deng , P. C. Ching , Zhi Ding

We communicate over wireless channels by first estimating and then equalizing the effective channel. In Zak-OTFS (orthogonal time frequency space) modulation the carrier waveform is a pulse in the delay-Doppler (DD) domain, formally a…

Signal Processing · Electrical Eng. & Systems 2025-07-08 Saif Khan Mohammed , Sandesh Rao Mattu , Nishant Mehrotra , Venkatesh Khammammetti , Robert Calderbank

Although it is often used in the orthogonal frequency division multiplexing (OFDM) systems, application of massive multiple-input multiple-output (MIMO) over the orthogonal time frequency space (OTFS) modulation could suffer from enormous…

Signal Processing · Electrical Eng. & Systems 2020-03-17 Yushan Liu , Shun Zhang , Feifei Gao , Jianpeng Ma , Xianbin Wang

Waveforms with ideal ambiguity functions are fundamental to integrated sensing and communication, to active sensing (radar), and to uplink multiple access. We describe a general method of constructing waveforms using the discrete Zak…

Signal Processing · Electrical Eng. & Systems 2025-04-01 Nishant Mehrotra , Sandesh Rao Mattu , Robert Calderbank
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