Abstract:

In the multiuser MIMO scenario, transceiver design and optimization techniques have been known to be very powerful in enhancing system throughput and efficiency. This talk will first focus on physical-layer MISO multicasting, or common information broadcast to multiple users. In this context, a popular approach is to assume the transmit beamforming  structure and design the beamformer via semidefinite relaxation (SDR). While this approach is effective for not too many number of users, there are few works that do the following rethinking: Can we obtain better designs by altering the physical-layer transceiver architecture itself? We will introduce a novel transceiver strategy called stochastic beamforming (SBF). SBF employs a random-in-time philosophy to circumvent the rank-one approximation issue inherent in SDR-based beamforming. By both simulations and theoretical analysis, we will show that SBF outperforms SDR-based beamforming when the number of users is large.

We will also describe another problem concerning robust unicast beamforming. Curiously, simulation results have suggested that SDR admits a rank-one solution to the aforementioned problem---or solves the problem optimally---in most instances. This gives rise to a fundamentally important question, namely, whether we can theoretically identify conditions under which the robust problem admits a rank-one solution. A latest theoretical breakthrough by the speakers and his collaborators will be described.

Biography:

Wing-Kin (Ken) Ma is an Associate Professor with the Department of Electronic Engineering, The Chinese University of Hong Kong. His research interests are in signal processing, communications and optimization, with recent activities focused on MIMO transceiver designs and interference management, blind signal processing and structured matrix factorization, and hyperspectral remote sensing.

Dr. Ma is active in the Signal Processing Society. He is currently a Senior Area Editor of IEEE Transactions on Signal Processing and previously served as editors of several journals, e.g., IEEE Signal Processing Magazine as the Lead Guest Editor of a special issue. He is a Member of the Signal Processing Theory and Methods (SPTM) Technical Committee and the Signal Processing for Communications and Networking (SPCOM) Technical Committee. He received Research Excellence Award 2013–2014 by CUHK, the 2015 IEEE Signal Processing Magazine Best Paper Award, and the 2016 IEEE Signal Processing Letters Best Paper Award. His students received ICASSP Best Student Paper Awards in 2011 and 2014. He is an IEEE Fellow.