An array processing approach to pilot decontamination for massive MIMO. - Karthik Upadhya; Sergiy A. Vorobyov (CAMSAP, 2015)

Downlink performance of superimposed pilots in massive MIMO systems in the presence of pilot contamination. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (GlobalSIP, 2016)

Superimposed pilots: An alternative pilot structure to mitigate pilot contamination in massive MIMO. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (ICASSP, 2016)

Superimposed Pilots are Superior for Mitigating Pilot Contamination in Massive MIMO - Part I: Theory and Channel Estimation. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (CoRR, 2016)

Superimposed Pilots are Superior for Mitigating Pilot Contamination in Massive MIMO: Part II - Performance Analysis and Hybrid System Design. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (CoRR, 2016)

A risk minimization framework for channel estimation in OFDM systems. - Karthik Upadhya; Chandra Sekhar Seelamantula; K. V. S. Hari (Signal Process., 2016)

Tracking abruptly changing channels in mmWave systems using overlaid data and training. - Karthik Upadhya; Robert W. Heath Jr.; Sergiy A. Vorobyov (CAMSAP, 2017)

Time-multiplexed / superimposed pilot selection for massive MIMO pilot decontamination. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (ICASSP, 2017)

Superimposed Pilots Are Superior for Mitigating Pilot Contamination in Massive MIMO. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (IEEE Trans. Signal Process., 2017)

Low-Overhead Receiver-Side Channel Tracking for Mmwave Mimo. - Karthik Upadhya; Sergiy A. Vorobyov; Robert W. Heath Jr. (ICASSP, 2018)

Covariance Matrix Estimation for Massive MIMO. - Karthik Upadhya; Sergiy A. Vorobyov (IEEE Signal Process. Lett., 2018)

Downlink Performance of Superimposed Pilots in Massive MIMO Systems. - Karthik Upadhya; Sergiy A. Vorobyov; Mikko Vehkaperä (IEEE Trans. Wirel. Commun., 2018)

On Achievable Rates for Massive Mimo System with Imperfect Channel Covariance Information. - Atchutaram K. Kocharlakota; Karthik Upadhya; Sergiy A. Vorobyov (ICASSP, 2019)

On the Spectral Efficiency for Massive MIMO Systems With Imperfect Spacial Covariance Information. - Atchutaram K. Kocharlakota; Karthik Upadhya; Sergiy A. Vorobyov (CoRR, 2019)

Jamming Detection with Subcarrier Blanking for 5G and Beyond in Industry 4.0 Scenarios. - Leonardo Chiarello; Paolo Baracca; Karthik Upadhya; Saeed R. Khosravirad; Thorsten Wild (PIMRC, 2021)

Nonlinear Precoding for Quantized Outphasing RF Chains in Massive MIMO Systems. - Karthik Upadhya; Stefan Wesemann (VTC Spring, 2021)

Extreme Communication in 6G: Vision and Challenges for 'in-X' Subnetworks. - Gilberto Berardinelli; Paolo Baracca; Ramoni O. Adeogun; Saeed R. Khosravirad; Frank Schaich; Karthik Upadhya; Dong Li; Tao Tao; Harish Viswanathan; Preben E. Mogensen (IEEE Open J. Commun. Soc., 2021)

Impact of Pilot Overhead and Channel Estimation on the Performance of Massive MIMO. - Atchutaram K. Kocharlakota; Karthik Upadhya; Sergiy A. Vorobyov (IEEE Trans. Commun., 2021)

Jamming Resilient Indoor Factory Deployments: Design and Performance Evaluation. - Leonardo Chiarello; Paolo Baracca; Karthik Upadhya; Saeed R. Khosravirad; Silvio Mandelli; Thorsten Wild (WCNC, 2022)

Passive Reflectors for Enhancing Cellular UAV Coverage. - Karthik Upadhya; Kimmo Valkealahti; Martti Moisio; Dani Korpi; Tero Ihalainen; Mikko A. Uusitalo (WCNC, 2022)

Digital Twins for Industry 4.0 in the 6G Era. - Bin Han 004; Mohammad Asif Habibi; Björn Richerzhagen; Kim Schindhelm; Florian Zeiger; Fabrizio Lamberti; Filippo Gabriele Pratticò; Karthik Upadhya; Charalampos Korovesis; Ioannis-Prodromos Belikaidis; Panagiotis Demestichas; Siyu Yuan; et al. (CoRR, 2022)

28 GHz NLOS Channel Measurements Revealing Low Path Loss and High Angular Spread in Container Ports. - Andrea Bedin; Dmitry Chizhik; Jinfeng Du; Martti Moisio; Karthik Upadhya; Reinaldo A. Valenzuela; Mikko A. Uusitalo (CoRR, 2023)

Heterogeneous Rank Beamforming for Industrial Communications. - Andrea Bedin; Akshay Jain 001; Andrea Zanella; Karthik Upadhya (CoRR, 2023)

LPD-Aware 5G NR Downlink Synchronization for Tactical Networks. - Akshay Jain 001; Karthik Upadhya; Mikko A. Uusitalo; Harish Viswanathan (ICMCIS, 2025)

Knowledge Graph-Based approach for Sustainable 6G End-to-End System Design. - Akshay Jain 001; Sylvaine Kerboeuf; Sokratis Barmpounakis; Cristóbal Vinagre Z.; Stefan Wendt; Dinh Thai Bui; Pol Alemany; Riccardo Nicolicchia; José María Jorquera Valero; Dani Korpi; Mohammad Hossein Moghaddam; Mikko A. Uusitalo; et al. (CoRR, 2025)