Sabera Kazi

MAC layer QoS support for wireless networks of unmanned air vehicles

Mission-critical applications in wireless environments depend on a cross layer approach for Quality of Service. Dealing efficiently with variable link quality and dynamic topologies involves QoS integration at the link, network and transport layer interfaces. In this paper, we present a new contention-based medium access control protocol for wireless ad-hoc networks of unmanned air vehicles. A receiver-initiated access control protocol with sender scheduling provides the mechanisms to implement effective MAC-layer bandwidth allocation with support for ad-hoc scenarios. A variable RTS lead time procedure integrated with binary exponential backoff improves fairness and provides low access latency for critical data frames. A major protocol design factor is efficient operation under heavy load. Performance measurements from simulations indicate consistent performance and promising results.

Adaptive LMS filter receiver for a turbo coded CDMA system

We demonstrate that the use of turbo codes and an adaptive filter receiver can significantly improve the bit error rate of a code division multiple access (CDMA) system. A system model is proposed to allow the study of turbo coding in CDMA systems using an additive white Gaussian noise channel and a Rayleigh fading channel. Coding is shown to provide improved response to both the near-far and the multipath problem.