Mehrdad Salimnejad - Communication systems
Date: - Location: Eurecom
Abstract: In this work, we study the real-time tracking and reconstruction of an information source with the purpose of actuation. A device monitors the state of the information source and transmits status updates to a receiver over a wireless erasure channel. We consider two models for the source, namely an N-state Markov chain and an N-state Birth-Death Markov process. We investigate several joint sampling and transmission policies, including a semantics-aware one, and we study their performance with respect to a set of metrics. Specifically, we investigate the real-time reconstruction error and its variance, the cost of actuation error, the consecutive error, and the cost of memory error. These metrics capture different characteristics of the system performance, such as the impact of erroneous actions and the timing of errors. In addition, we propose a randomized stationary sampling and transmission policy, and we derive closed-form expressions for the aforementioned metrics. We then formulate two optimization problems. The first optimization problem aims to minimize the time-averaged reconstruction error subject to time-averaged sampling cost constraint. Then, we compare the optimal randomized stationary policy with uniform, change-aware, and semantics-aware sampling policies. Our results show that in the scenario of constrained sampling generation, the optimal randomized stationary policy outperforms all other sampling policies when the source is rapidly evolving. Otherwise, the semantics-aware policy performs the best. The objective of the second optimization problem is to obtain an optimal sampling policy that minimizes the average consecutive error with a constraint on the time-averaged sampling cost. Based on this, we propose a wait-then-generate sampling policy which is simple to implement. Bio: My name is Mehrdad Salimnejad. I received my bachelor's degree in Electrical Engineering-Electronics from Razi University, Iran in 2012. Furthermore, I received an M.Sc. degree in Electrical Engineering-Communication Systems from the University of Tehran, Iran in 2015. During my M.Sc. program I derived analytical expressions for the best relay location in two-way relay networks with spatially-random relays. The title of my thesis was “Statistical Analysis of the Best Relay Location in a Random Two-Way Relay Network with Multi-Slope path loss”. After receiving my M.Sc., I joined Research Center of Sharif University of Technology, Iran in which I had a great opportunity to work on some of leading projects in the field of Wireless Communication Systems and Signal Processing. Since January 2022, I have been a Ph.D. student at the Department of Computer and Information Science at Linköping University, Sweden under the supervision of Prof. Nikolaos Pappas and co-supervision of Prof. Marios Kountouris. I am working on a project with focus on Information Handling in Industrial IoT. The goal is to work on designing concrete metrics of assessing information significance and will develop multiple access and transmission schemes. My main research areas include Semantic Wireless Communication, Age of Information, and Communication Networks.
