Dr. Tharm Ratnarajah

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fred harris Endowed Chair Professor
Department of Electrical and Computer Engineering
College of Engineering
Academic Affairs

SDSU

Email

Primary Email: [email protected]

Building/Location

Engineering and Interdisciplinary Sciences Complex - 318
5500 Campanile Dr.
San Diego, CA 92182

Bio

Prof. Tharm Ratnarajah works as a Fred Harris Endowed Chair in Digital Signal Processing at San Diego State University and Director of the Communication Systems and Signal Processing Institute. His research interests include signal processing and information-theoretic aspects of beyond 5G cellular networks, full-duplex radio, mmWave communications, random matrix theory, big data analytics and machine learning for wireless networks, statistical and array signal processing, physical-layer secrecy and interference alignment. He has published over 475 Peer-reviewed papers in these areas and holds four US patents. He was the lead coordinator of the European Union (EU) projects HARP (4.6Me) in the area of highly distributed MIMO and ADEL (3.7Me) in the area of licensed shared access. He was also the coordinator of the European Union Future and Emerging Technologies project CROWN (3.4Me) in the area of cognitive radio networks and HIATUS (3.6Me) in the area of interference alignment. Prof Ratnarajah was an associate editor of IEEE Transactions on Signal Processing, 2015-2017, and Technical co-chair of the 17th IEEE International Workshop on Signal Processing Advances in Wireless Communications, Edinburgh, UK, 3-6, July 2016. Prof. Ratnarajah is a Fellow of the Higher Education Academy (FHEA).

Full publication and research interest can be found at http://www.profratnarajah.org/

Areas of Specialization

  • Semantic communications
  • In-band full-duplex radio
  • Integrated sensing and communications
  • Distributed/Federated learning
  • An IRS-aided multiuser wireless communications
  • Deep-receiver design for wireless communications
  • Physical layer secrecy
  • Caching and machine learning in wireless communication networks
  • Big data-aware wireless network design
  • Massive MIMO (mMIMO) systems / Cell-free mMIMO
  • Spectrum sharing techniques (LSA, CBRS, NOMA)
  • mmWave communications
  • Random matrix theory and information theory
  • Statistical and radar signal processing
  • Integrating terrestrial and non-terrestrial networks

Courses

  • Digital Communications
  • Wireless Communications
  • Computational and Statistical Methods for Data Science
  • Machine Learning for Signal Processing
  • Coding Theory

Publications

RECENT JOURNAL PUBLICATIONS (total 196)

[1] Y. Mu, X. Liu, and T. Ratnarajah, "Adaptive Model Pruning in Decentralized Federated Learning," IEEE Trans on Network Science and Engineering, Vol 13, pp. 327-343, 2026.

[2] S. Nassirpour, T-V Nguyen, H-Q Ngo, L-N Tran, T. Ratnarajah; D H. N. Nguyen, "Variational Bayesian Channel Estimation and Data Detection for Cell-Free Massive MIMO with Low-Resolution Quantized Fronthaul Links," IEEE Journal of Selected Topics in Signal Processing, Vol. 19, Issue 6, pp. 1187-1202, Sep. 2025.​

[3] S. S. Hassan, ..., T. Ratnarajah, "Quantum Machine Learning for 6G Space-Air-Ground Integrated Networks: A Comprehensive Tutorial and Survey," IEEE Communications Surveys and Tutorials, Vol. 28, pp. 3710-3750, Sep. 2025.

[4] Z. Liu and T. Ratnarajah, "Multi-user Semantic Communication for Interactive Speech Dialogue with Dynamic Resource Allocation," IEEE Trans on Network Science and Engineering, Vol. 12, No. 5, pp. 3901-3918, Sep/Oct 2025.

[5] Z. Liu, N. Garg, and T. Ratnarajah, "Dynamic Energy Efficient Resource Allocation for Massive MIMO Networks Using Randomized Ensembled Double Q-learning Algorithm," IEEE Trans. on Cognitive Communications and Networking, Vol. 11, Issue 4, pp. 2201-2215, Aug. 2025.

[6] H. Luo, N. Garg, M. Holm and T. Ratnarajah, "Joint Power Allocation and Beamforming for In-band Full-duplex Multi-cell Multi-user Networks," IEEE Trans on Vehicular Technology, Vol. 74, No. 4, pp. 5799-5813, April 2025.

[7] Y. Li, S. K. Podilchak, J. Zhang, S. L. Cotton, T. Ratnarajah, and Y. Ding, "RFFI Protocols Using Antenna Mutual Coupling and Power Amplifier Nonlinear Memory Effects," IEEE Communications Letters, Vol. 29, Issue 6, pp. 1250-1254, 2025.

[8] S. Lavery and T. Ratnarajah, "OFDM-based Remote Sensing Utilizing the 4D Modified Matrix Pencil Method," IEEE Transactions on Radar Systems, Vol. 3, pp. 318-331, 2025.

[9] Z. Liu, N. Garg, and T. Ratnarajah, "Multi-agent Federated Q-learning Algorithms for Wireless Edge Caching," IEEE Trans on Vehicular Technology, Vol. 74, No. 2, pp 2973-2988, 2025.

RECENT CONFERENCE PUBLICATIONS (total 287)

[1] N. Jain, S. Biswas, C. C. Tsimenidis, S. Mumtaz, and T. Ratnarajah, "Hybrid Quantum-Classical Coverage Optimization for User-Centric 6G Movable Antenna Systems," In Proc. of the IEEE International Conference on Communications, Glasgow, Scotland, UK, 24–28 May 2026.

[2] S. S. Hassan, A. Adhikary, N. Das, S. Sharma, and T. Ratnarajah, "OTFS-Enabled ISAC Scheduling for LEO Satellite with Reconfigurable Holographic Surfaces Using a Transformer Approach," In Proc. the IEEE Wireless Communications and Networking Conference, Kuala Lumpur, Malaysia, April 13-16, 2026.

[3] S. S. Hassan, L. X. Nguyen, U. Majeed, Z. Han, C. S Hong, and T. Ratnarajah, "Denoising-Enabled Semantic Communication for Robust Earth Observation in 6G Satellite Networks: A Swin Transformer Approach," In Proc. the IEEE Wireless Communications and Networking Conference, Kuala Lumpur, Malaysia, April 13-16, 2026.

[4] S. S. Hassan, Y M. Park, L. X. Nguyen, Y. K. Tun, C. S. Hong, and T Ratnarajah, "Sustainable UAV-Mounted Active Reconfigurable Intelligent Surface for Remote User Connectivity via Learning-Based Optimization," In Proc. IEEE Global Communications Conference, Taipei, Taiwan, Dec. 8–12, 2025.

[5] Z. Liu and T. Ratnarajah, "Semantic Communication for Speech Question Answering Tasks,” In Proc. 59th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, California, Oct. 26-29, 2025.

[6] A. Taimori, M. Sellathurai, and T. Ratnarajah, "Differential semantic communications for salient object transmission in 6G multimedia systems," In Proc. on IEE International Conference on Computer Communications, 19-22 May 2025, London, UK.

[7] S. S. Hassan, Yu M. Park, Z. Han, and T. Ratnarajah, "Spectrum Efficiency Optimization in 6G Satellite Networks: A Inverse Reinforcement Learning Approach," In Proc. on IEEE International Conference on Machine Learning for Communication and Networking, 26-29 May 2025, Barcelona, Spain.

[8] S. Nassirpour, T-V Nguyen, T. Ratnarajah, and D. H. N. Nguyen, "Sum-Rate Maximization in Holographic MIMO Communications with Stacked Intelligent Metasurfaces," In Proc. of the IEEE International Conference on Communications, 8–12 June 2025. Montreal, Canada.

Full publication list can be found at http://www.profratnarajah.org/