Average BER estimation of retroreflective transdermal optical wireless links with diversity, attenuation and spatial jitter

Remarkable recent advances in both medical and optical wireless communication (OWC) fields have paved the way to move to the more bandwidth-effective optical spectrum in order to establish high speed transdermal optical wireless (TOW) communication links between an implanted device and an external one, which is very crucial for a variety of emerging medical applications. However, the development of optical telemetry with medical implants is primarily hindered by skin-induced attenuation and pointing errors effects. In order to combat these dominant impairments, a modulated retro-reflector (MRR) TOW system with diversity is investigated in terms of its total average bit error rate (ABER) performance metric. Thus, taking into account the joint presence of skin-induced path loss along with the stochastic nature of pointing errors due to random misalignments between transmitter and receiver terminals, novel analytical ABER expressions are extracted for various MRR TOW configurations in order to investigate the influence of the diversity technique. Additionally, proper corresponding analytical results are provided which are further validated by Monte Carlo simulations in an attempt to verify the new mathematical expressions and reveal the beneficial impact of diversity method employment on the total ABER performance of a typical MRR TOW system.