Adaptive Transmission Protocols for Cognitive Radios in Dynamic Spectrum Access Networks

Event Date: February 27, 2009
Speaker: Michael B. Pursley
Speaker Affiliation: Clemson University
Sponsor: CNSIP Area Seminar
Time: 11:30 AM
Location: EE 170
Contact Name: Prof Lehnert
Contact Phone: 765-494-2362
Contact Email:
Open To: Acceptable for ECE694A
A protocol suite is presented for initializing and adapting
transmissions in cognitive radio networks with dynamic frequency
assignments.  A framework based on resource consumption is provided for
the selection of the initial modulation to be used in a session after a
frequency band has been designated.  During the first few packet
transmissions in a new session, a power-adjustment protocol compensates
for uncertainties in the propagation characteristics and interference in
the designated frequency band.  During the session, the error-control
code and modulation are adapted to accommodate time-varying interference
and propagation loss.  Because increases in transmitter power can
disrupt ongoing sessions in the network, the transmitter power is
increased only if adaptation of coding and modulation cannot compensate
fully for a deterioration that occurs in the channel.  Protocol
performance results are provided for static channels with unknown
characteristics and for dynamic channels that are modeled as
finite-state Markov chains.  Comparisons with hypothetical ideal
protocols and Shannon capacity bounds are employed to assess the
efficiency of the protocols.

Biographical Sketch

Michael Pursley received his BSEE and MSEE degrees from Purdue in 1967
and 1968, respectively.  He received a PhD in electrical engineering
from the University of Southern California in 1974.  Before beginning
his academic career, he worked for the Space and Communications Group of
the Hughes Aircraft Company during 1968--74, after which he was an ECE
faculty member at the University of Illinois, Urbana-Champaign, until
1993.  Since then, he has been the Holcombe Professor of Electrical and
Computer Engineering at Clemson University.  His research is in wireless
communications and information theory with emphasis on spread-spectrum
communications, adaptive protocols for packet radio networks, dynamic
use of spectrum, and cognitive radio.

Dr. Pursley is a member of Phi Eta Sigma, Tau Beta Pi, the ACM, the
Institute of Mathematical Statistics, and an honorary member of Golden
Key.  He was elected Fellow of the IEEE in 1982 and President of the
IEEE Information Theory Society in 1983.  He is a Senior Editor of the
IEEE Journal of Selected Areas in Communications.  He is the author of
two textbooks published by Prentice Hall: Random Processes in Linear
Systems (2002) and Introduction to Digital Communications (2005).  Dr.
Pursley is the recipient of several awards and honors, including the
IEEE Communications Society Armstrong Achievement Award and a
Distinguished Alumni Award from the University of Southern California
Viterbi School of Engineering.

Direct any questions to: Prof. Lehnert (494-2362;