Performance of a high-speed transcutaneous link with error correction coding

Abstract

A Register Transfer Level (RTL) design that integrates a figure-8 multi-band inductive link (MIL), a bi-level pulse harmonic modulation (PHM) system, and a Gallager A decoder is presented and verified. Integrating this MIL with a PHM system can lead to optimizing power efficiency, data rate, and transmitter power consumption in near field transcutaneous wireless communication systems for cortical implants (CI). Also, a technique to increase the data rate of PHM systems based in multi-level transmission (MLT) is presented. MLT is an attractive solution to increasing data rates in PHM systems while meeting power consumption constraints, since it does not require increasing the frequency of the harmonics generated in the PHM receiver. Verilog Analog Mixed Signal (AMS) was used to verify these systems. The distance between external and implanted coils was modeled to be 10 mm.From the power interference characterization of the bi-level system, it was observed that for every value of the coupling coefficient between the power transmitter coil and data receiver coil (k 14 ), there is a different comparator reference voltage that can minimize the bit error rate (BER) of the system and optimize decoder performance. Moreover, it is shown that as k 14 increases, this optimal reference voltage also increases. Therefore, it is expected that a control system that could adapt the comparator reference voltages to changes in (k 14 ), could enhance robustness of PHM systems against factors that can increase MIL power iv interference, such as misalignments. From the verification of the MLT technique, it was observed that the optimal delay between initiation and suppression pulses (t d ) of a PHM system varies with respect to initiation pulse amplitudes, contrary to what had been stated in the past in previous PHM system verifications. Furthermore, it is concluded that, unless the pulse pattern generator (PPG) is designed to vary t d according to the initiation pulse transmitted, MLT-based PHM systems would be too vulnerable to non-idealities, such as noise and misalignments, preventing its feasibility. From the transmitter (TX) clock jitter characterizations, it was concluded that as the PHM levels of transmission increase, systems become more sensitive to jitters. Finally, the Gallager A decoder was found powerful in enhancing the robustness of PHM systems against power interference, TX clock jitter, and noise. Cortical implants (CI) can be used in medicine to treat neurological disorders, and to serve as substitutes of damaged organs in the nervous system. Currently, active research is being developed in the wireless data and power transfer to CIs, in order to avoid frequent surgical interventions to replace batteries and potential paths of infection due to wires breaching the skin. In this paper, we consider performance optimization strategies for a pulse-based wireless link that have been proposed recently. We consider two enhancements that may allow for increased throughput in this system. First, a low-power error-correcting ...