100 Mbit/s IrDA optical wireless throughput performance analysis

Existing IrDA standard optical wireless links operate at data rates up to 16 Mbit/s. Such links are incorporated into millions of products such as mobile phones, personal digital assistants, laptop and palmtop PCs. Longer term, IrDA is destined to create standards for links at even higher data rates. The performance of such links depends crucially on the efficient operation of the IrDA IrLAP protocol. The authors examine the IrDA IrLAP protocol performance at data rates up to 100 Mbit/s. Using a mathematical analysis based on the concept of ´window transmission time´, the throughput equation of IrLAP is derived. Subsequently, optimum values for important design parameters of the link layer such as window size and frame length are derived, for maximum IrLAP throughput as a function of BER. The results indicate that the IrLAP protocol offers excellent performance even at 100 Mbit/s. High link layer throughput even at high data bit error rates is possible provided the IrLAP window size and frame length values are adapted to optimum values for the corresponding BER. Results are presented on link performance limited due to the turnaround time. Such results are important to hardware manufacturers of high speed optical wireless links.