Protocols for Adaptive Modulation and Coding in Dynamic Spectrum Access Networks

SPEAKER: Michael B. Pursley, Holcombe Professor, Clemson UniversityABSTRACT: A protocol suite is presented for controlling transmissions in dynamic spectrum access networks. A framework 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. Throughout 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 other sessions that are underway in the network, the transmitter power is increased only if adaptation of coding and modulation cannot compensate fully for deteriorations in the channel conditions. 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 Shannon capacity limits are employed to assess the efficiency of the adaptive coding protocol for a wide range of modulation techniques and channel models.Host: Prof. Robert Scholtz, scholtz@usc.edu

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248

Audiences: Everyone Is Invited

Contact: Mayumi Thrasher