Exploiting Cooperative Diversity in Slotted ALOHA Random Access Networks

Speaker: Y.-W. Peter Hong
National Tsing Hua University, TaiwanAbstract:
In a cooperative system, each user exploits spatial diversity by transmitting their packets through multiple
relaying paths provided by their cooperative partners. Most works in the literature on cooperative
communications focus on the physical layer aspects such as coding, modulation, transceiver signal processing
etc. In this talk, we will discuss the advantages of user cooperation from a MAC layer perspective and devise
queueing strategies to exploit the cooperative diversity gains in a random access network. Specifically, we
propose two queueing strategies for the cooperative system and study their respective stability regions. We
show that both schemes outperform the case with no cooperation, especially when one user has a better channel
than the other. We then extend our system to networks that consist of multiple cooperating pairs and study the
stability of the finite-user cooperative system. By treating each cooperative pair as a transmission entity, we
derive inner bounds for the finite-user stability region and propose a ranking system to characterize the entities'
relative tendency of being stable (or unstable).Biography:
Y.-W. Peter Hong received his B.S. degree in Electrical Engineering from National Taiwan University, Taipei,
Taiwan, in 1999, and his Ph.D. degree in Electrical Engineering from Cornell University, Ithaca, NY, in 2005.
In 2005, he joined the Institute of Communications Engineering/Department of Electrical Engineering in
National Tsing Hua University, Hsinchu, Taiwan, where he is currently an Assistant Professor. His research is
focused on cooperative communications, distributed signal processing for sensor networks, and PHY-MAC
cross-layer designs for next generation wireless networks. He received the best paper award among unclassified
papers in MILCOM 2005 and the best paper award for young authors from the IEEE IT/COM Society
Taipei/Tainan chapter in 2005. He is a co-editor (along with A. Swami, Q. Zhao and L. Tong) of the book
entitled "Wireless Sensor Networks: Signal Processing and Communications Perspectives" (John-Wiley, 2007).Host: Professor C.-C. Jay Kuo

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: Talyia Veal