Research interests

Our interest is in all three fundamental aspects of 5G/6G wireless system design

• Theoretical research: Please see below for some example research areas and tools we use. Please see “Papers” tab for more details.

• Standardization: Please see 5G,6G project tab on the areas in which we contribute to 5G+/6G standards.

• System design: Please see 5G Testbed, 4G,3G tabs on the different generation of cellular system prototypes we have built.

Current theoretical research on following 5G/6G wireless technologies

• Massive MIMO, cell-free massive MIMO, full-duplex, millimeter wave wireless communication networks.

• Extra large massive MIMO systems.

• Orthogonal time frequency space (OTFS) systems.

• Ultra reliable low-latency (URLLC) and massive machine type communications (mMTC) systems.

• Intelligent reflective surfaces (IRS).

• Device-to-Device (D2D)/Vehicle-to-Vehicle (V2V) communication systems.

• Unmanned aerial vehicle (UAV) wireless systems.

Tools used to design analyze and optimize 5G/6G systems

• Machine learning and deep learning

• Convex and non-convex optimization methods

• Random matrix theory and linear algebra

• Information theory

Example research works

Machine learning and deep learning

• Sparse Bayesian learning to design algorithms for Cloud-RAN and mMTC systems

  • See our following papers e.g., [pdf-link, [pdf-link], [pdf-link], [pdf-link],[pdf-link]

• Deep learning to optimize massive MIMO wireless systems

  • See our following papers e.g., [pdf-link],[pdf-link]

Design of cell-free massive MIMO systems

• • Current 5G massive MIMO networks have cellular architecture which impairs the performance of cell-edge users

  • Design, analyze and optimize cell-free massive MIMO systems which overcome these limitation for 5G+ networks

  • See our following papers e.g., [pdf-link], [pdf-link],[pdf-link]

Intelligent reflective surface (IRS) for 5G and beyond communications

• IRS can change the wireless propagation environment by instantaneously modifying the phase of transmit signal

  • Analyzed and optimized the performance of cellular system integrated with IRS

  • See our following paper e.g., [pdf-link].

Massive Machine Type Communication (mMTC) Systems

• 5G systems connect machines along with humans

  • These systems need to first detect active machines before detecting their data

  • Design algorithms for such systems

  • See our following paper e.g., [pdf-link], [pdf-link].

OTFS system design for high-speed vehicular communications

• OTFS can combat inter-subcarrier interference which occurs at extremely high vehicular speed

  • OFDM performance degrades due to this interference

  • OTFS receiver design has extremely high complexity. Designed low-complexity receivers.

  • See our following papers e.g., [pdf-link],[pdf-link],[pdf-link].

Design of full duplex massive MIMO systems

• • Current 5G systems are half-duplex which can either transmit or receive

  • Consider full duplex systems and analyze and optimize their performance

  • See our following papers e.g., [pdf-link], [pdf-link]

Design of energy-efficient NOMA massive MIMO systems

• • Wireless systems are conventionally designed to optimize spectral efficiency

  • Due to extremely high energy requirements of wireless systems, they are being designed to optimize energy efficiency

  • See our following papers e.g., [pdf-link], [pdf-link],[pdf-link]

Example papers for mathematical tools we use in our research

Convex/non-convex optimization, random matrix theory

• Analysis of practical massive MIMO systems with spatial correlation and hardware impairments

  • Practical massive MIMO systems experience spatially correlated channels

  • They are also designed using low-cost RF components which experience hardware impairments

  • We mathematically model such massive MIMO systems and analyze the performance

  • See our following papers e.g., [pdf-link],[pdf-link],[pdf-link],[pdf-link]

Distributed optimization for massive MIMO systems

• Develop optimization algorithms which can be executed on distributed processor architecture

  • See our following synchronous and synchronous ADMM papers e.g., [pdf-link], [pdf-link],[pdf-link]

Linear algebra and optimization for robust wireless transceiver design

• Design wireless transceivers when with channel is not completely known at the transmitter

  • See our recent paper where we used fundamental properties of SVD e.g., [pdf-link]