Reliable Wireless Communication for Medical Devices Using Turbo Convolution Code

Wireless technology is now being used to bring significantly innovative products and services in the healthcare sector, enabling new medical sensors, and treatment methods. In this paper, a new and improved communication system for communicating signals among different medical devices and a console is presented. Considering the need for very high degree of functional reliability of communication link in RF challenged environment (indoor), a novel algorithm called bi-directional “Soft Output Viterbi Algorithm (SOVA)” decoding for double-binary Circular Recursive Systematic Convolutional (CRSC) turbo codes is presented. The bi-directional SOVA is considered in view of its better performance and implementation complexity trade-off. The basic SOVA has been described for binary turbo code. We have extended it for double binary case, which is useful for high data rate healthcare applications using real time streaming data. Necessary changes in basic message passing equations for double-binary case have been introduced. Coding gain can be used to increase the robustness and immunity to interference. Decoding of CRSC codes requires a prologue decoder, prior to the actual trellis decoding, to estimate the initial state. Efficient determination of circulation state through prologue decoding has helped in achieving impressive error performance for CRSC codes. The issues related to digital implementation of turbo encoder/decoder and their effects on error performance have also been discussed. Adequate simulation results have been included.

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