Next-Generation Radar Waveform Design: Intelligent, Game-Theoretic, and Learning-Driven



Radar waveform design is fundamental to enhancing radar sensing performance. This research explores advanced methods using intelligent optimization, game theory, and meta-learning to solve the core trade-offs among resolution, ambiguity, and robustness in complex electromagnetic environments. We aim to significantly improve target detection, tracking, and identification in next-generation active sensing systems.

The core challenge lies in efficiently finding optimal or sub-optimal waveforms within a constrained high-dimensional parameter space. Our work unifies analytical, model-based, and data-driven approaches within this framework.

By developing new design paradigms that integrate intelligent decision-making and adaptive learning, this research provides key theoretical and technological foundations for future cognitive and collaborative radar systems.

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Integrated Sensing and Communications: Intelligent Waveforms, Collaborative Sensing, and Cross-Layer Optimization



Integrated Sensing and Communications (ISAC) is a key paradigm for next-generation wireless networks, unifying communication and sensing functions for synergistic performance gains. Our research focuses on three interconnected layers: intelligent waveform design, multi-node collaborative sensing, and cross-layer resource optimization, addressing fundamental challenges in spectrum sharing, performance trade-offs, and system efficiency.

We develop unified waveforms that ensure compatibility between high-rate communication and high-accuracy sensing. Through architectures leveraging intelligent reflecting surfaces and distributed nodes, we overcome the limitations of single-station systems. Finally, our cross-layer optimization frameworks dynamically allocate resources based on sensing tasks and network conditions for global system efficiency.

This integrated "signal-architecture-system" approach provides fundamental support for realizing the high-reliability, low-latency, and high-precision sensing-communication capabilities required in future 6G networks.

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Reconfigurable Electromagnetic Environments: Intelligent Surfaces and Dynamic Arrays



Reconfigurable electromagnetic environments enable revolutionary control over wireless propagation and radiation characteristics. This research investigates intelligent reflecting surfaces (RIS) and dynamic antenna arrays (e.g., fluid antennas) to overcome fundamental limitations in wireless sensing, such as coverage gaps, multipath fading, and restricted viewing angles.

Our work spans both passive and active reconfiguration. Intelligent surfaces dynamically shape wireless channels to enhance signal strength and diversity. Dynamic arrays enable real-time beamforming and pattern adaptation for precise and agile sensing.

By co-designing channel control and antenna systems, this research builds the foundation for robust, adaptive, and intelligent next-generation wireless sensing.

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Distributed Sensing and Localization: Synthetic Aperture, Optimal Deployment, and Resource Allocation



Distributed sensing and localization utilize networked nodes to achieve superior accuracy and robustness beyond single-station capabilities, such as distributed coherent aperture radar (DCAR). Our research focuses on three pillars: virtual aperture synthesis, optimal sensor deployment, and dynamic resource allocation, addressing the trade-offs among accuracy, cost, and efficiency in complex environments. 

We create virtual apertures from distributed nodes for high-resolution, long-range imaging. Using tools like the Cramér–Rao Bound, we optimize sensor placement and configuration to maximize accuracy under practical constraints. We also develop resource allocation strategies that dynamically manage spectrum, power, and computation across heterogeneous networks for optimal system performance.

This integrated "deployment-processing-scheduling" framework provides core theories and system solutions for reliable sensing and localization in future IoT and emerging aerial networks.

Book Chapters

● L. Wu and D. P. Palomar,“Cognition-enabled waveform design for ambiguity function shaping,”in Next Generation Cognitive Radar Systems, Ch. 6, K. V. Mishra, B. Shankar M.R., and M. Rangaswamy, The Institution of Engineering and Technology, 2023.

● L. Wu and D. P. Palomar,“Radar Waveform Design via Majorization Minimization,”in Radar Waveform Design based on Optimization Theory, Ch. 7, G. Cui, A. DeMaio, A. Farina, and J. Li, The Institution of Engineering and Technology, 2020.

Journal Papers (* indicates corresponding author, students worked with me are underlined)

● Z. Cheng, L. Wu*, Y. Li, B. Shankar and H. Li,“Two Birds, One Stone: A Per-Frame Approach for Joint Channel Estimation and Target Tracking in HBF-DFRC Systems,”IEEE Transactions on Communications, vol. 73, no. 11, pp. 12294-12309, Nov. 2025.

● S. Xu, L. Wu, X. Li, X. Wu and T. Xu,“AOA Sensor Placement for Anchor-Assisted Target Localization in GNSS-Denied Environment: Formulation, Bounds and Optimization,”IEEE Transactions on Mobile Computing, vol. 24, no. 10, pp. 10792-10806, Oct. 2025.

● S. Xu, L. Wu*, K. Dogancay, M. R. B. Shankar, K. C. Ho and X. Wu,“Optimal Sensor Placement for Target Localization in IoT Systems: A Cramér-Rao Bound Perspective,”in IEEE Internet of Things Magazine, vol. 8, no. 5, pp. 120-126, Sept. 2025.

● Y. Liu, L. Wu*, X. Cai, and B. Shankar,“Graph-Based Multi-Bounce Modeling and Channel Parameter Estimation for Indoor Sensing,”IEEE Transactions on Wireless Communications, vol. 24, no. 5, pp. 4219-4234, May 2025.

● X. Feng, Z. Zhao, H. Huang, L. Wu, Z. Zhao,“Sidelobe Suppression with Low Peak-to-Valley Power Ratio Waveforms in MIMO-OFDM Dual-Function Radar-Communication Systems,”IEEE Transactions on Vehicular Technology, vol. 74, no. 4, pp. 5928-5940, April 2025.

● H. Huang, M. F. Keskin, H. Wymeersch, X. Cai, L. Wu*, J. Thunberg, and F. Tufvesson,“Hybrid Precoder Design for Angle-of-Departure Estimation with Limited-Resolution Phase Shifters,”IEEE Transactions on Communications, vol. 73, no. 6, pp. 4439-4453, June 2025.

● Z. Xie, L. Wu*, X. Huang, C. Fan, J. Zhu, and W. Liu,“Cross Ambiguity Function Shaping of Cognitive MIMO Radar: A Synergistic Approach to Antenna Placement and Waveform Design,”IEEE Transactions on Geoscience and Remote Sensing, vol. 62, pp. 1-13, 2024.

● T. Wei, L. Wu*, K. V. Mishra, and B. Shankar,“RIS-Aided Wideband Holographic DFRC,”IEEE Transactions on Aerospace and Electronic Systems, vol. 60, no. 4, pp. 4241-4256, Aug. 2024.

● Z. Xie, L. Wu*, J. Zhu, M. Lops, X. Huang, and B. Shankar,“RIS-Aided Radar for Target Detection: Clutter Region Analysis and Joint Active-Passive Design,”IEEE Transactions on Signal Processing, vol. 72, pp. 1706-1723, 2024.

● X. Feng, L. Wu, Y. Zhao, Z. Zhao, K. Diao, and M. Soltanalian,“Recurrent Waveform Optimization for Desired Range-Doppler Profile With Low Probability of Interception: A Particle Filter Approach,”IEEE Transactions on Aerospace and Electronic Systems, vol. 60, no. 2, pp. 1899-1911, April 2024.

● T. Wei, L. Wu*, K. V. Mishra, and B. Shankar,“Multi-IRS-Aided Doppler-Tolerant Wideband DFRC System,”IEEE Transactions on Communications, vol. 71, no. 11, pp. 6561-6577, Nov. 2023.

● L. Wu, N. Sahu, S. Xu, P. Babu, and D. Ciuonzo,“Optimization Based Sensor Placement for Multi-Target Localization with Coupling Sensor Clusters,”IEEE Transactions on Signal Processing and Information Processing over Networks, vol. 9, pp. 596-611, 2023.

● M. Alaee-Kerahroodi, L. Wu, E. Raei, and B. Shankar,“Improving Precipitation Estimation via Joint Transmit-Receive Design for Solid State Weather Radar Systems,”IEEE Transactions on Radar Systems, vol. 1, pp. 212-229, 2023.

● L. Wu, X. Cheng, H. Huang, D. Ciuonzo, and B. Shankar,“Constant-Modulus Waveform Design with Polarization-Adaptive Power Allocation in Polarimetric Radar,”IEEE Transactions on Signal Processing, vol. 71, pp. 2146-2161, 2023.

● H. Huang, L. Wu*, B. Shankar, and A. M. Zoubir,“Sparse Array Design for Dual-Function Radar-Communications System,”IEEE Communications Letters, vol. 27, no. 5, pp. 1412-1416, May 2023.

● Z. Cheng, L. Wu*, J. An, and Z. He,“Relative Entropy Based Constant-Envelope Beamforming for Target Detection in Large-Scale MIMO Radar With Low Resolution ADCs,”IEEE Transactions on Vehicular Technology, vol. 72, no. 8, pp. 10090-10106, Aug. 2023.

● X. Cheng, L. Wu, D. Ciuonzo, and W. Wang,“Joint Design of Horizontal and Vertical Polarization Waveforms for Polarimetric Radar Via SINR Maximization,”IEEE Transactions on Aerospace and Electronic Systems, vol. 59, no. 3, pp. 3313-3328, June 2023.

● Z. Cheng, L. Wu*, B. Wang, B. Shankar, and B. Ottersten,“Double-Phase-Shifter based Hybrid Beamforming for mmWave DFRC in the Presence of Extended Target and Clutters,”IEEE Transactions on Wireless Communications, vol. 22, no. 6, pp. 3671-3686, June 2023.

● L. Chen, V. N. Ha, E. Lagunas, L. Wu, S. Chatzinotas, and B. Ottersten,“The Next Generation of Beam Hopping Satellite Systems: Dynamic Beam Illumination with Selective Precoding,”IEEE Transactions on Wireless Communications, vol. 22, no. 4, pp. 2666-2682, April 2023.

● B. Wang, L. Wu, Z. Cheng, and Z. He,“Exploiting Constructive Interference in Non-linear Symbol Level Hybrid Beamforming for Dual-Function Radar-Communication System,”IEEE Wireless Communications Letters, vol. 11, no. 10, pp. 2071-2075, Oct. 2022.

● M. Deng, Z. Cheng, L. Wu, B. Shankar, and Z. He,“One-Bit ADCs/DACs based MIMO Radar: Performance Analysis and Joint Design,”IEEE Transactions on Signal Processing, vol. 70, pp. 2609-2624, 2022.

● S. Xu, L. Wu*, K. Doğançay, and M. Alaee-Kerahroodi,“A Hybrid Approach to Optimal TOA-Sensor Placement with Shared Sensors for Simultaneous Multi-Target Localization,”IEEE Transactions on Signal Processing, vol. 70, pp. 1197-1212, 2022.

● T. Wei, L. Wu*, and B. Shankar,“Joint Waveform and Precoding Design for Joint Radar-Communication SINR Optimization,” IET Signal Processing, vol. 16(7), pp. 788–799, 2022. 

● L. Wu*, K. V. Mishra, B. Shankar, and B. Ottersten,“Resource Allocation in Heterogeneously-Distributed Joint Radar-Communications under Asynchronous Bayesian Tracking Framework,”IEEE Journal of Selected Areas in Communications, vol. 40, no. 7, pp. 2026-2042, July 2022.

● N. Sahu, L. Wu*, P. Babu, B. Shankar, and B. Ottersten,“Optimal sensor placement for source localization: A unified ADMM approach,”IEEE Transactions on Vehicular Technology, vol. 71, no. 4, pp. 4359-4372, April 2022.

● R. Zhou, L. Wu*, and R. S. Cheng,“Energy-Efficiency-Oriented Charge Scheduling and Beamforming for a Two-Tier Wireless Powered Network,”IEEE Internet of Things Journal, vol. 7, no. 3, pp. 2212-2222, Dec. 2019.

● L. Wu*, Y. Feng, and D. P. Palomar,“General Sparse Risk Parity Portfolio Design via Successive Convex Optimization,”Signal Processing, vol. 170, pp. 1-13, Dec. 2019.

● L. Wu* and D. P. Palomar,“Sequence Design for Spectral Shaping via Minimization of Regularized Spectral Level Ratio,”IEEE Transactions on Signal Processing, vol. 67, no. 18, pp. 4683-4695, Sep. 2019.

● L. Wu*, P. Babu, and D. P. Palomar,“Transmit Waveform/Receive Filter Design for MIMO Radar with Multiple Waveform Constraints,”IEEE Transactions on Signal Processing, vol. 66, no. 6, pp. 1526-1540, Mar. 2018.

● L. Wu*, P. Babu, and D. P. Palomar,“Cognitive Radar-Based Sequence Design via SINR Maximization,”IEEE Transactions on Signal Processing, vol. 65, no. 3, pp. 779-793, Feb. 2017.

Conference Papers (students worked with me are underlined)

● Z. Xiao, L. Wu, M. R. Bhavani Shankar and B. Ottersten, "RIS-Enabled Self-Interference Cancellation in Monostatic OFDM-ISAC," 2025 IEEE Radar Conference (RadarConf25), Krakow, Poland, 2025

● K. Zhong et al., "RIS-Aided MIMO Radar Beampattern Matching," 2025 IEEE Radar Conference (RadarConf25), Krakow, Poland, 2025

● D. An et al., "Movable Antenna Aided Hybrid Beamforming for Wideband MIMO Radar Sensing,"2025 IEEE Radar Conference (RadarConf25), Krakow, Poland, 2025

● D. Saha, A. E. Olk, L. Wu, M. Ahmadi and M. R. B. Shankar, "NLoS Radar Sensing for Breathing Rate Estimation in Indoor Environments: An Experimental Study," 2025 IEEE Radar Conference (RadarConf25), Krakow, Poland, 2025

● T. Wei, K. Mishra, L. Wu, and B. Shankar,“Wideband Beamforming with Frequency-Spatial Coupling in Near-Field Holographic ISAC,”in the 33rd European Signal Processing Conference (EUSIPCO), Palermo, Italy, 2025.

● Z. Yang, L. Wu, and Z. Zhao,“Mutual Information Maximization for MIMO Waveform Design Using Minorization-Maximization,”in the 33rd European Signal Processing Conference (EUSIPCO), Palermo, Italy, 2025.

● Y. Liu, L. Wu, X. Cai, and B. Shankar,“Environment Reconstruction in Multi-Bounce Channels with Array Partial Blockage,”in the 33rd European Signal Processing Conference (EUSIPCO), Palermo, Italy, 2025.

● T. Wei, K. V. Mishra, L. Wu, and B. Shankar,“Cramér-Rao bounds for wideband near-field sensing,”in IEEE Int. Conf. Acoust., Speech, Signal Process. (ICASSP), Hyderabad, India, 2025.

● L. Wu, Z. Xiao, B. Shankar, and B. Ottersten,“RIS-enabled self-interference elimination in monostatic full-duplex DFRC systems,”in IEEE Int. Conf. Acoust., Speech, Signal Process. (ICASSP), Hyderabad, India, 2025.

● D. Ciuonzo, A. Zappone, M. Di Renzo, and L. Wu,“Massive MIMO channel-aware decision fusion aided by reconfigurable intelligent surfaces,”in /IEEE Int. Conf. Acoust., Speech, Signal Process. (ICASSP), Hyderabad, India, 2025.

● K. P. Rajput, L. Wu, B. Shankar, B. Ottersten, and P. Varshney,“Tracking time-varying parameters in massive MIMO IoT networks: A linear coherent decentralized approach,”in IEEE Int. Conf. Acoust., Speech, Signal Process. (ICASSP)/, Hyderabad, India, 2025.

● R. Amar, L. Wu, S. Sedighi, M. Alaee, and B. Shankar,“Dual-function waveform design in wireless sensor networks via SoS optimization,”in IEEE Int. Conf. Acoust., Speech, Signal Process. (ICASSP), Hyderabad, India, 2025.

● D. Saha, A. E. Olk, L. Wu and B. Shankar,“Broadband Design of Reflective Multi-Resonator Metasurface for V-Band Applications,”18th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials), Chania, Greece, 2024

● L. Wu, W. Liu, B. Shankar and B. Ottersten,“Enhanced Jamming Suppression in Colocated MIMO Radar with Fluid Antenna Array,”in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), Corvallis, USA, Jul. 2024.

● K. P. Rajput, L. Wu, B. Shankar and P. K. Varshney,“Joint Transmit Precoders and Passive Reflection Beamformer Design in IRS-Aided IoT Networks,”in Proc. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Seoul, Korea, Republic of, 2024.

● Y. Liu, M. R. Bhavani Shankar, L. Wu and B. Ottersten,“Debris Sensing Based on LEO Constellation: An Intersatellite Channel Parameter Estimation Approach,”in Proc. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Seoul, Korea, Republic of, 2024.

● Y. Yao, F. Shu, L. Wu, X. Cheng, X. Li and J. Wang,“Anti-Jamming Strategy for IRS-Aided JRC System in Vehicular Networks,”in Proc. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Seoul, Korea, Republic of, 2024.

● M. Ahmadi, M. Alaee-Kerahroodi, L. Wu, B. Shankar and B. Ottersten,“Detector Design for Distributed Multichannel Radar Sensors in Colored Interference Environments,”in Proc. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Seoul, Korea, Republic of, 2024.

● Y. Liu, W. Long, R. Chen, L. Wu, and B. Shankar,“Vortex Wavefront FMCW ISAC Model: A Blender-Based Evaluation,”in Proc. IEEE 24th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Shanghai, China, 2023.

● L. Wu, K. P. Rajput, Y. Liu, and B. Shankar,“Distributed Sensing and Centric Computing via FMCW Waveform in Wireless Sensor Network,”in Proc. IEEE 24th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Shanghai, China, 2023.

● K. P. Rajput, L. Wu, and B. Shankar,“Next-Generation IoT Networks: Integrated Sensing Communication and Computation,”in Proc. IEEE 48th International Conference on Acoustics, Speech and Signal Processing (ICASSP), Rhodes, Greece, Jun. 2023.

● L. Wu, B. Wang, Z. Cheng, B. Shankar M. R., and B. Ottersten,“Joint Symbol-Level Precoding and Sub-Block-Level RIS Design for Dual-Function Radar-Communications,”in Proc. IEEE 48th International Conference on Acoustics, Speech and Signal Processing (ICASSP), Rhodes, Greece, Jun. 2023.

● T. Wei, L. Wu, K. V. Mishra, and B. Shankar M. R.,“RIS-Aided Wideband DFRC with Reconfigurable Holographic Surface,”in Proc. IEEE 48th International Conference on Acoustics, Speech and Signal Processing (ICASSP), Rhodes, Greece, Jun. 2023.

● S. Zhao, Y. Liu, L. Wu, J. Rodriguez-Pineiro, X. Yin, and J. Hong,“Recursive UE Localization for a Multi-RIS-Assisted Wireless System in an Obstacle-Dense Environment,”in Proc. 17th European Conference on Antennas and Propagation (EuCAP), Florence, Italy, Mar. 2023.

● B. Wang, Z. Cheng, L. Wu, and Z. He,“Hybrid Beamforming Design for OFDM Dual-Function Radar-Communication System with Double-Phase-Shifter Structure,”in Proc. 30th European Signal Processing Conference (EUSIPCO), Belgrade, Serbia, Aug. 2022.

● T. Wei, L. Wu, K. V. Mishra, and B. Shankar M. R.,“Simultaneous Active-Passive Beamformer Design in IRS-Enabled Multi-Carrier DFRC System,”in Proc. 30th European Signal Processing Conference (EUSIPCO), Belgrade, Serbia, Aug. 2022.

● S. Shi, Z. Cheng, L. Wu, Z. He, and B. Shankar M. R.,“Distributed 5G NR-Based Integrated Sensing and Communications Systems: Frame Structure and Performance Analysis,”in Proc. 30th European Signal Processing Conference (EUSIPCO), Belgrade, Serbia, Aug. 2022.

● L. Wu, M. Alaee-Kerahroodi, and B. Shankar,“Improving Pulse-Compression Weather Radar via the Joint Design of Subpulses and Extended Mismatch Filter,”in Proc. The International Geoscience and Remote Sensing Symposium (IGARSS), Kuala Lumpur, Malaysia, Jul. 2022.

● S. Xu, L. Wu, B. Shankar, and P. Babu,“Integrated Trajectory Optimization and Cubature Kalman Filter for UAV-Based Target Tracking with Unknown Initial Position,”in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), Trondheim, Norway, Jun. 2022.

● T. Wei, L. Wu, K. V. Mishra, and B. Shankar M. R.,“IRS-Aided Wideband Dual-Function Radar-Communications with Quantized Phase-Shifts,”in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), Trondheim, Norway, Jun. 2022.

● Y. Liu, L. Wu, M. Alaee-Kerahroodi, and B. Shankar M. R.,“A 3D Indoor Localization Approach Based on Spherical Wave-front and Channel Spatial Geometry,”in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), Trondheim, Norway, Jun. 2022.

● B. Wang, Z. Cheng, L. Wu, and Z. He,“Hybrid Beamforming Design for Single-User OFDM Dual-Function Radar-Communication System with Space-Frequency Nulls,”in Proc. IEEE Wireless Communications and Networking Conference (WCNC), Austin, TX, USA, Apr. 2022.

● L. Wu, J. Dai, B. Shankar, R. Hu, and B. Ottersten,“Recurrent Design of Probing Waveform for Sparse Bayesian Learning Based DOA Estimation,”in Proc. IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Singapore, May 2022.

● T. Wei, L. Wu, K. V. Mishra, and B. Shankar M. R.,“Multi-IRS-Aided Wideband Integrated Sensing and Communications,”in Proc. IEEE JC&S Symposium, Innsbruck, Austria, Mar. 2022.

● X. Cheng, L. Wu, T. Wei, D. Ciuonzo, and W. Wang,“Transmit Signal Design for Polarimetric Radars under Local Waveform Constraints,”in Proc. CIE International Conference on Radar, Haikou, China, Dec. 2021.

● T. Wei, L. Wu, and B. Shankar M. R.,“Sparse Array Beampattern Synthesis via Majorization Based ADMM,”in Proc. IEEE Vehicular Technology Conference (VTC2021-Fall), Online, Sep. 2021.

● T. Wei, L. Wu, M. Alaee-Kerahroodi, and B. Shankar M. R.,“Transmit Beampattern Synthesis for Planar Array with One-bit DACs,”in Proc. International Radar Symposium (IRS), Online, Jun. 2021.

● L. Wu, K. V. Mishra, B. Shankar M. R., and B. Ottersten,“Heterogeneously Distributed Joint Radar Communications: Bayesian Resource Allocation,”in Proc. IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Lucca, Italy, Sep. 2021.

● L. Wu, P. Babu, and D. P. Palomar, “A Fast Algorithm for Joint Design of Transmit Waveforms and Receive Filters,” in Proc. IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Sapporo, Japan, Jul. 2017.

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