A Coherent Theory of Random Access
Abstract: Random access provides a simple and elegantsolution for multiple users to share a common channel. Studies on random-accessprotocols date back to 1970s.With decades of extensive research, random accesshas found wide applications to various wireless networks including cellularnetworks, WiFi networks and sensor networks. The minimum coordination anddistributed control make it especially appealing for low-cost data networks. In sharp contrast to the simplicity inconcept, performance analysis of random-access networks has long been known asnotoriously difficult. Although it has been long observed that a random-accessnetwork may suffer from significant performance degradation when the networksize and/or traffic input rates increase, how to properly choose key systemparameters to optimize the network performance is little understood. In thistalk, I will introduce my recent work on modeling and performance optimizationof random-access networks. I will show that the key to performance analysis ofa random-access network lies in proper characterization of the service timedistributi on of each node’s queue. Based on the proposed node-centric model, aunified analytical framework can be established to characterize the fundamentallim its of random-access networks, and to evaluate effects of key parameters ona wide range of performance metrics in a systematic manner. I will conclude thetalk by demonstrating how to apply the proposed theory to guide the optimalaccess design of WiFi networks. Inthe end of my talk, I will also introduce the MSc/PHD programs of Department ofElectronic Engineering of City University of Hong Kong, and variousopportunities for scholarships. Prospective students are welcome to attend anddiscuss with me after the talk. Aboutthe speaker: Dr. Lin Dai received the B.S. degree fromHuazhong University of Science and Technology, Wuhan, China, and the M.S. andPh.D. degrees from Tsinghua University, Beijing, China, all in electronicengineering. She was a postdoctoral fellow at the Hong Kong University ofScience and Technology and University of Delaware. Since 2007, she has beenwith City University of Hong Kong, where she is currently an AssociateProfessor. She has broad interests in communicationsand networking theory, with special interests in wireless communications. Herrecent research work focuses on modeling, performance analysis and optimalaccess design of next-generation mobile communication systems. She was aco-recipient of the Best Paper Awardat the IEEE Wireless Communications and Networking Conference (WCNC) 2007 andthe IEEE Marconi Prize Paper Award(the annual Best Paper Award of IEEE Transactions on Wireless Communications)in 2009. She served as a co-chair of PHY Track ofIEEE WCNC 2013, and the leading co-chair of Wireless Communications Symposiumof IEEE ICC 2015. She received The President's Award of City University of HongKong in 2017. Since 2014, she has been serving as an editor for IEEETransactions on Wireless Communications , and an assistant dean of College ofScience and Engineering of City University of Hong Kong.