Cooperative-diversity slotted ALOHA

We propose a cooperative-diversity technique for ad hoc networks based on the decode-and-forward relaying strategy. We develop a MAC protocol based on slotted ALOHA that allows neighbors of a transmitter to act as relays and forward a packet toward its final destination when the transmission to the intended recipient fails. The proposed technique provides additional robustness against fading, packet collisions and radio mobility. Network simulations confirm that under heavy traffic conditions, in which every radio always has packets to send, the proposed cooperative-diversity slotted-ALOHA protocol can provide a higher one-hop and end-to-end throughput than the standard slotted-ALOHA protocol can. A similar advantage in end-to-end delay can be obtained when the traffic is light. As a result, the proposed cooperative-diversity ALOHA protocol can be used to improve these measures of Quality of Service (QoS) in ad hoc wireless networks. John M. Shea (S’92–M’99) received the B.S. (with highest honors) in Computer Engineering from Clemson University in 1993 and the M.S. and Ph.D. degrees in electrical engineering from Clemson University in 1995 and 1998, respectively. Dr. Shea is currently an Associate Professor of electrical and computer engineering at the University of Florida. Prior to that, he was an Assistant Professor at the University of Florida from July 1999 to August 2005 and a post-doctoral research fellow at Clemson University from January 1999 to August 1999. He was a research assistant in the Wireless Communications Program at Clemson University from 1993 to 1998. He is currently engaged in research on wireless communications with emphasis on error-control coding, cross-layer protocol design, cooperative diversity techniques, and hybrid ARQ. Dr. Shea was selected as a Finalist for the 2004 Eta Kappa Nu Outstanding Young Electrical Engineer Award. He received the Ellersick Award from the IEEE Communications Society in 1996. Dr. Shea was a National Science Foundation Fellow from 1994 to 1998. He is an Associate Editor for the IEEE Transactions on Vehicular Technology. Tan F. Wong received the B.Sc. degree (1st class honors) in electronic engineering from the Chinese University of Hong Kong in 1991, and the M.S.E.E. and Ph.D. degrees in electrical engineering from Purdue University in 1992 and 1997, respectively. He was a research engineer working on the high speed wireless networks project in the Department of Electronics at Macquarie University, Sydney, Australia. He also served as a post-doctoral research associate in the School of Electrical and Computer Engineering at Purdue University. Since August 1998 he has been with the University of Florida, where he is currently an associate professor of electrical and computer engineering. He serves as Editor for Wideband and Multiple Access Wireless Systems for the IEEE Transactions on Communications and as the Editor for the IEEE Transactions on Vehicular Technology.