Multiple Input Multiple Output InVivo Communication for Nano Sensor at Terahertz Frequencies

This study presents a preliminary feasibility investigation of signal propagation and antenna diversity techniques inside the human skin tissues in the frequency range (0.8-1.2)Terahertz (THz) by applying multiple input-single output (MISO) technique. THz application in in-vivo communication has received a great attention for its unique properties as non ionizing characteristics, strong interaction with water content inside the human tissues, and molecular sensitivity [1]. This study helps to evaluate the usage and the performance of MISO system for nanoscale network. The human skin tissue is represented by three main layers: stratum corneum, epidermis, and dermis. The path loss model and the channel characterization inside the human skin was investigated in [2]. The diversity gain (DG) for two different in-vivo channels resulting from the signal propagation between two transmitting antennas, located at the dermis layer, and one receiving antenna, located at epidermis layer, is calculated to evaluate the system performance. Different diversity combining techniques are applied in this study: selection combining (SC), equal-gain combing (EGC), and maximum-ratio combining (MRC). In the simulation setting in CST microwave studio, the distance between the transmitting antennas is fixed; while the effect of the distance between the receiver and the transmitters is analyzed at different frequencies. Although MIMO antenna systems are used in wireless communication to enhance data throughput, from the initial study it is predicted that might be it is not useful in in-vivo nano communication. Results demonstrates that there is a high cross correlation between the two channels. Fig. 1 shows the CDF plot for the two channel with different diversity combining techniques used in the study.[1] J. M. Jornet and I. F. Akyildiz, “Channel modeling and capacity analysis for electromagnetic wireless nanonetworks in theterahertz band,” IEEE Transactions on Wireless Communications, vol. 10, no. 10, pp. 3211–3221, 2011.[2] Q. H. Abbasi, H. El Sallabi, N. Chopra, K. Yang, K. A. Qaraqe, and A. Alomainy, “Terahertz channel characterizationinside the human skin for nano-scale body-centric networks,” IEEE Transactions on Terahertz Science and Technology, vol.6, no. 3, pp. 427–434, 2016