Graduate Seminar – “Fundamentals of Heterogeneous Cellular Networks”
February 13, 2014
Dr. Harpreet Dhillon, Postdoctoral Research Associate
University of Southern California – Los Angeles
When: Friday, February 28, 2014 at 3:05 p.m.
Where: Warnock 1230
The increasing complexity of heterogeneous cellular networks (HetNets) due to the irregular deployment of small cells demands significant rethinking in the way cellular networks are perceived, modeled and analyzed. In addition to threatening the relevance of classical models, this new network paradigm also questions the feasibility of state-of-the-art simulation-based approach for system design. In this talk, I will discuss an alternate approach based on random spatial models that is not only tractable but also captures current deployment trends fairly accurately.
First, I will present a general baseline model consisting of K different types of base stations (BSs) that may differ in terms of transmit power, deployment density and target rate. Modeling the locations of each class of BSs as an independent Poisson Point Process (PPP) allows the derivation of surprisingly simple expressions for key performance metrics. One interpretation of these results is that adding more BSs or tiers does not necessarily change the coverage probability, which indicates that the fears of “interference overload” in HetNets are probably overblown.
Second, I will discuss how the baseline model can be generalized to study self-powered HetNets, where each BS is powered solely by a self-contained energy harvesting module that may differ across tiers in terms of the energy harvesting rate and energy storage capacity. Since a BS may not always have sufficient energy, it may not always be available to serve users. This leads to a notion of “availability region”, which characterizes the fraction of time each type of BS can be made available under a variety of operational strategies. The availability region also provides a way to quantify performance degradation due to the unreliability associated with energy harvesting.
Time permitting, I will also discuss a few more topics of current interest, most notably: (i) multi-antenna HetNets, and (ii) ongoing work on wireless backhaul networks.
Harpreet S. Dhillon received the B.Tech. in Electronics and Communication Engineering from Indian Institute of Technology (IIT) Guwahati, India, in 2008, the M.S. in Electrical Engineering from Virginia Tech, Blacksburg, VA, in 2010, and the Ph.D. in Electrical Engineering from the University of Texas (UT) at Austin, TX, in 2013. Since Fall 2013, he is a postdoctoral research associate in the Communication Sciences Institute (CSI), Department of Electrical Engineering, University of Southern California (USC), Los Angeles, CA. He has held summer internships at Alcatel-Lucent Bell Labs in Crawford Hill, NJ, Samsung Research America in Dallas, TX, Qualcomm Inc. in San Diego, CA, and Cercom, Politecnico di Torino in Italy.
Dr. Dhillon is a recipient of the IEEE International Conference in Communications (ICC) 2013 best paper award in Wireless Communications Symposium, UT Austin’s Wireless Networking and Communications Group (WNCG) leadership award 2013, UT Austin’s Microelectronics and Computer Development (MCD) fellowship, and the Agilent Engineering and Technology Award 2008, a national award for the best undergraduate research thesis in India. His research interests are broadly in communication theory, stochastic geometry, and wireless ad hoc and cellular networks. For more details, please refer to: https://webspace.utexas.edu/hd3496/www/.