Performance Evaluation of Spatial Diversity Techniques in Transdermal Optical Communications with Pointing Errors

Modem medical applications including Active Medical Implants (AMI) require a reliable high-speed communication link between a transceiver located inside the human body, and another transceiver located outside the body. In several literatures, Optical Wireless communications have shown superiority over the commonly used Radio Frequency (RF) technology in terms of bandwidth utilization, data rates and interference immunity. Unfortunately, this superiority comes at the expense of having strict alignment requirement between both transmitting and receiving ends. In this paper Novel closed form expression is derived for Bit Error Rate performance for transdermal optical wireless channel, assuming intensity modulation/direct detection with On-Off Keying (IMDD/OOK). The derived expression takes into account the combined effect of the random pointing error process and the deterministic skin thickness attenuation. The results are evaluated for different channel severity, utilizing Maximal Ratio Combiners (MRC) diversity technique, as a function of signal-to-noise ratios. Finally, the numerical results were verifred using computer based Monte-Carlo (MC) simulation, leading to good agreement between the simulated and the numerical results.