OFDM Multiple Antennas Cognitive Radio Relay CDMA Synchronization Channel Estimation Spectrum Sharing Interference Cancellation Full duplex Spectrum Sensing Resource Allocation Neural Networks Stochastic Geometry Equalizer Bi-Directional Feedback Femtocell Energy Harvesting Heterogeneous Networks Device-to-Device (D2D) Cross-link interference Cell Search SINR mismatch problem Ultra-dense small cell networks HetNet Idle cells Spectral efficiency Dynamic TDD interference management NOMA FBMC selection diversity Handoff outage probability mode selection B5G multi-spectral achievable sum rate Grant-free Transmission Filtered OFDM tabu-search bursty traffic model flexible duplex 5G Asynchronous Transmission Preamble Deep learning Shortened TTI automatic repeat request (ARQ) Two-way communications transmission capacity (TC) in-band full-duplex system self-interference cancellation Complexity Ultra-dense small cell sensing duration Correlated MIMO Cognitive relay networks Heterogeneous channel estimation capability Bi-directional full-duplex full-duplex cellular full-duplex relay Simultaneous Sensing and Transmission UWB OQAM Windowing Vehicle-to-vehicle communication prototype filter pilot signal LTE-based V2V link reliability resource size control interference to noise ratio eigen decomposition TS-W-OFDM C-V2V massive connectivity Reliability Vehicle-to-Vehicle full-spreading NOMA Resource management Cooperative systems Coexistence scenarios mixed numerology 6G Cell-free Coexisting network Multiple access Railway CP-OFDM MLP Edge computing Full-duplex Mobility non-orthogonal multiple access HST interference mitigation Computation offloading TDD configuration Singular Vale Decomposition
Status : Published 
Date : 2020-11 
Title : A New Non-Orthogonal Transceiver for Asynchronous Grant-Free Transmission Systems 
Authors : Soohyun Kim, Jeeyeon Kim, and Daesik Hong 
Journal : IEEE Transactions on Wireless Communications 
Abstract : The grant-free non-orthogonal multiple access (GF-NOMA) system, in which users autonomously transmit uplink data signals without carrying out a complicated random access process, offers significant advantages for increasing the efficiency of resource usage with low signaling overhead. In the proposed GF-NOMA system, since the collision resolution process is omitted and resources are not pre-assigned to users, multiple users may use same resource, without the base station (BS) being able to identify these collided users. In addition, in the absence of the UL synchronization procedure generally performed in the random access process, multiple users’ signals are received asynchronously. To solve these problems, we have developed a new transceiver structure for the GF-NOMA system consisting of a secondary preamble and a multiuser-multisymbol (MUMS) detector. The purpose of the secondary preamble is to successfully detect user access and estimate channel information even when no collision resolution process is being performed. The MUMS receiver is then proposed as a way to effectively mitigate the severe interference caused by the asynchronous transmission. Simulation results show that the proposed preamble structure and the receiver structure are superior to the conventional schemes. Furthermore, we show that the GF-NOMA system with the proposed transceiver structure achieves much better performance than other GF-NOMA systems in terms of reliability and successfully detected bits. 
URL : https://ieeexplore.ieee.org/document/9262029 

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List of Articles
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» [IEEE Trans. Wireless Commun.] Soohyun Kim, Jeeyeon Kim, and Daesik Hong, "A New Non-Orthogonal Transceiver for Asynchronous Grant-Free Transmission Systems," in IEEE Transactions on Wireless Communications, March 2021 Published  2020-11 
1 [IEEE Trans. Wireless Commun.] Jaeyoung Choi, Beomju Kim, Kwonjong Lee, and Daesik Hong, "A Transceiver Design for Spectrum Sharing in Mixed Numerology Environments", IEEE Trans. on Wireless Comm., Mar. 2019 Published  2019-03