Intra-Body Optical Channel Modeling for In Vivo Wireless Nanosensor Networks
Intra-Body Optical Channel Modeling for In Vivo Wireless Nanosensor Networks
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DOI：
10.1109/tnb.2015.2508042
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发表时间：
2016-01-01
影响因子：
3.9
通讯作者：
Sun, Zhi
中科院分区：
文献类型：
--
作者：
Guo, Hongzhi;Johari, Pedram;Sun, Zhi
体内无线纳米传感器网络（iWNSN）由纳米级通信设备组成，可以在人体内实时运行。 iWNSN 是变革性医疗保健技术的基础，范围从体内健康监测系统到药物输送应用。等离子体纳米天线有望实现近红外和光传输窗口中纳米传感器之间的通信。这一结果激发了对影响此类电磁（EM）信号在人体内传播的现象的分析。在本文中，开发了纳米传感器之间体内光通信的通道模型。总路径损耗是通过考虑不同类型分子的吸收和不同类型细胞的散射来计算的。具体而言，首先，通过将细胞建模为具有复介电常数的多层球体，分析获得单个细胞对光波传播的影响。然后，分析在分层组织中排列大量具有不同特性的细胞的影响。分析信道模型通过电磁仿真进行验证，并提供大量数值结果以了解体内光学无线信道的行为。结果表明，在光频率下，细胞引入的散射损耗远大于介质的吸收损耗。这一结果促使 iWNSN 中利用近红外窗口的较低频率进行通信。
In vivo wireless nanosensor networks (iWNSNs) consist of nanosized communicating devices, which can operate inside the human body in real time. iWNSNs are at the basis of transformative healthcare techniques, ranging from intra-body health-monitoring systems to drug-delivery applications. Plasmonic nanoantennas are expected to enable the communication among nanosensors in the near infrared and optical transmission window. This result motivates the analysis of the phenomena affecting the propagation of such electromagnetic (EM) signals inside the human body. In this paper, a channel model for intra-body optical communication among nanosensors is developed. The total path loss is computed by taking into account the absorption from different types of molecules and the scattering by different types of cells. In particular, first, the impact of a single cell on the propagation of an optical wave is analytically obtained, by modeling a cell as a multi-layer sphere with complex permittivity. Then, the impact of having a large number of cells with different properties arranged in layered tissues is analyzed. The analytical channel model is validated by means of electromagnetic simulations and extensive numerical results are provided to understand the behavior of the intra-body optical wireless channel. The result shows that, at optical frequencies, the scattering loss introduced by cells is much larger than the absorption loss from the medium. This result motivates the utilization of the lower frequencies of the near-infrared window for communication in iWNSNs.