Optimisation of IrDA IrLAP link access protocol.

Abstract

The widespread installation of millions of Infrared Data Association (IrDA) infrared (IR) ports in mobile devices for wireless communication applications necessitates for throughput performance optimization of the IR links at the IrDA link access protocol (IrLAP) link layer. For IrDA connectivity, link-layer throughput optimization is important for any line bit-error rate (BER). The paper provides a mathematical model with which we derive a simple equation linking IrLAP throughput with physical and link-layer parameters. Simple equations for optimum values of window size and frame length for maximum link-layer throughput as a function of BER are derived. A study of the importance of parameters such as link minimum turnaround time and -timer time out period is presented. Finally, a protocol improvement that utilizes special supervisory frames (frames) to pass transmission control is proposed to deal with delays introduced by -timer expiration. Results indicate that employing the special frame highly improves throughput performance when optimum window and frame-size values are implemented.