Applied and Interdisciplinary Mathematics(AIM) Seminar

Title: Wireless Video Streaming with Delayed Client-Feedback: A Constrained Decentralized Team View

Speaker:  Vijay Subramanian (University of Michigan)

Date: Thursday, March 28, 2024
Time: 1:30-2:30 pm
Location: 509/511 Lake Hall

Abstract: We study the optimal control of multiple video streams over a wireless downlink from a base-transceiver-station (BTS)/access point to N end-devices (EDs). The BTS sends video packets to each ED under a joint transmission energy constraint, the EDs choose when to play out the received packets, and the collective goal is to provide a high Quality-of-Experience (QoE) to the clients/end-users. All EDs send feedback about their states and actions to the BTS which reaches it after a fixed deterministic delay. We analyze this team problem with delayed feedback as a cooperative Multi-Agent Constrained Partially Observable Markov Decision Process (MA-C-POMDP). 
 
A core result that we will discuss is a recently established strong duality result for MAC-POMDPs. Using this new result the original video-streaming problem is decomposed into N independent unconstrained transmitter-receiver (two-agent) problems—all sharing a Lagrange multiplier (that also needs to be optimized for optimal control). Thereafter, the common information (CI) approach and the formalism of approximate information states (AISs) are used to guide the design of a neural-network based architecture for learning-based multi-agent control in a single un- constrained transmitter-receiver problem. Finally, simulations on a single transmitter-receiver pair with a stylized QoE model are performed to highlight the advantage of delay-aware two-agent coordination over the transmitter choosing both transmission and play-out actions (perceiving the delayed state of the receiver as its current state).
 
This is joint work with Nouman Khan (University of Michigan, Ann Arbor), and Ujwal Dinesha, Subrahmanyam Arunachalam, Dheeraj Narasimha, and Srinivas Shakkottai at TAMU. It is based on two recent papers, one presented at IEEE CDC 2023 and the other accepted at IEEE INFOCOM 2024.
 
Bio: Vijay Subramanian received the Ph.D. degree in electrical engineering from the University of Illinois at Urbana-Champaign,  Champaign, IL, USA, in 1999. He worked at Motorola Inc., and at the Hamilton Institute, Maynooth, Ireland, for many years, and also in the EECS Department, Northwestern University, Evanston, IL, USA. In Fall 2014, he started in his current position as an Associate Professor with the  EECS Department at the University of Michigan, Ann Arbor. For the academic year 2022-2023, he was an Adjunct Research Associate Professor in CSL and ECE at UIUC, and he continues to hold this position in academic year 2023-2024 as well. His research interests are in stochastic analysis, random  graphs, multi-agent systems, and game theory (mechanism and information design) with applications to social, economic and technological networks.