OFDM Relay Cognitive Radio Multiple Antennas Resource Allocation Full Duplex Spectrum Sensing Synchronization Spectrum Sharing Interference Cancellation Channel Estimation Feedback Heterogeneous Networks Bi-directional Energy Harvesting Stochastic Geometry HetNet relay networks FBMC Equalization channel capacity TVWS CDMA interference in-band full-duplex system Duplex MIMO Ultra Low Power C-V2V 5G Reliability SC-FDMA interference suppression D-TDD CLI indoor positioning reinforcement learning RSRP weighting - Computation offloading smart factory Cell-free multi-access edge computing estimated position overlapping —Device-to-device (D2D) estimated position updating mMIMO control overhead hybrid NR positioning Femtocell Rat-dependent positioning frame structure Zigbee body area networks channel estimation error Handoff CoMP User grouping power uncertainty ultra-dense small cell network mode selection antenna arrays 5G mobile communication UFMC resource block management inter user interference WVAN health care partial overlap GFDM Dynamic TDD Multi-user Receiver Number of training blocks Uplink SCMA system V2X Vehicular communication cross-link interference LTE-TDD FS-NOMA Location-based user fairness Mode 3 QR Factorization Metaheuristics P-NOMA non-orthogonal multiple access dynamic HetNet spectrum partitioning and 5G networks. massive connectivity non-orthogonal multiple access (NOMA) overloading DQN OTDOA distributed mode Communication range resource selection maximum likelihood method Resource sharing Power allocation packet delay
Status : Presented 
Date : 2022-06 
Title : Cell-Free mMIMO Systems with Dynamic TDD 
Authors : Hanwoong Kim, Hakkeon Lee, Taehyung Kim, and Daesik Hong 
Conference : IEEE VTC Spring 2022 
Abstract : Cell-free massive multi-input multi-output (CF-mMIMO) systems assume that a single central processing unit (CPU) communicates with a large number of user equipments (UEs) using the same time-frequency resources. However, allocating the same frame configuration to all the UEs makes it difficult to meet the traffic demands of each individual UE. In this paper, we propose using dynamic-time division duplex (D-TDD) in CF-mMIMO systems. To mitigate the cross-link interference (CLI), we propose a new UE-grouping algorithm. Simulation results show that the implementation of D-TDD reduces the median value of the UL packet delay and the DL packet delay by up to 75% and 30% respectively. Furthermore, the proposed UE-grouping reduces the average packet delay by 50% compared to static-TDD (S-TDD). 
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» [IEEE VTC] Hanwoong Kim, Hakkeon Lee, Taehyung Kim, and Daesik Hong, "Cell-Free mMIMO Systems with Dynamic TDD" IEEE VTC Spring 2022 Presented  2022-06