Modelling and simulation of wireless sensor system for health monitoring using HDL and Simulink® mixed environment

The aim of this study is to model and design an efficient wireless system that is easy to integrate with other technologies or infrastructures at a low cost. The system would read analogue information recorded by a biomedical sensor in a transmitting unit attached to the patient. The recorded data are converted digitally using analogue-to-digital converter and sent to frequency-shift keying (FSK) transmitter through field programmable gate arrays (FPGAs). Verilog-HDL has been used to implement the required functions of the FPGA, such as bus interfacing, data buffering, compression and data framing. On the other hand, Simulink® software has been used to model and simulate FSK transmitter/receiver architecture suitable for short-range communications. Basically, a two-tone FSK signal is generated and passed through a noisy channel, which is then downconverted to baseband and passed to the frequency-modulating detector to restore the original transmitted bit stream. These illustrate how easily the mixed signal modelling can be well mapped into hardware description language (HDL) and mathematical programming techniques. The developed simulation models are used to explore the design change options. The behavioural HDL design has been interfaced to the Simulink model using system generator in a co-simulation environment, and the overall performance has been verified.