Ultra geniş bantli i̇n vivo radyo kanalinin matematiksel modellemesi ve karakteristik analizi

In this research, we present the experimental analysis of in vivo wireless channel response on Ultra-Wideband (UWB) with the frequencies between 3.1 – 10.6 GHz. The analysis proves the location-dependent based characteristics of in vivo channel. The results clearly show the highly multipath scenario. It can also be observed that the multipath effect of the channel is much higher in the denser areas, i.e. an antenna placed within the intestine area or inside the stomach. which is used as a reference model for in vivo channel response without performing intensive experiments or simulations. The statistics of error prediction between experimental and proposed model is RMSE = 5.29, which show the high accuracy of the proposed model. In addition, the proposed model was applied on the blind data and the statistics of error prediction is RMSE = 7.76, which also shows a reasonable accuracy of the model. This model will save the time and cost on simulations, experiments and will help in designing an accurate link budget calculation for future enhanced system. This study also presents bit error rate (BER) performance analysis and improvement using equalizers for an in vivo radio channel. By conducting simulations using a bandwidth (BW) of 50 MHz, we observed that the in vivo radio channel is affected by small-scale fading. This fading results in inter-symbol interference (ISI) affecting upcoming symbol transmission, causing delayed versions of the symbols to arrive at the receiver side and causes increase in BER. A 29 taps channel was observed from the experimentally measured data using a human cadaver and BER was calculated for the measured in vivo channel response along with the ideal additive white Gaussian noise (AWGN) and Rayleigh channel models. Linear and non-linear adaptive equalizers i.e., decision feedback equalizer (DFE) and least mean square (LMS) were used to improve the BER performance of the in vivo radio channel. It is noticed that both the equalizers improve the BER, but DFE has better BER compared to LMS and shows a 2 dB and 4 dB performance gain of DFE over the LMS at Eb/No = 12 dB and at Eb/No = 14 dB, respectively.