Monitoring the physical parameters from devices inside the body, using ultra wideband (UWB) technology, enables the development of high bandwidth demanding applications in real time. The relative movement of the nodes deployed in the body, due to breathing, can give rise to a frequency shifting effect, increasing the fading level in the propagation channel during transmissions. In this article, therefore, we present a study of the frequency effects on the propagation channel derived from the relative movement between two nodes of a wireless body area network (WBAN), at least one of them placed inside the human body, caused by breathing. The study is performed on the basis of the Doppler spectrum characterization in terms of the shape fitting and frequency spread parameter derivation. Continuous wave (CW) signals have been used to cover the UWB range at four selected frequencies: 3.1, 4.8, 6, and 8.5 GHz, and a liquid phantom has been employed for emulating the dielectric properties of the high water content tissues at the considered UWB frequencies.

中文翻译：

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呼吸期间超宽带 BAN 信道中的多普勒表征

使用超宽带 (UWB) 技术监控体内设备的物理参数，可以实时开发高带宽要求的应用程序。由于呼吸，部署在体内的节点的相对运动会引起频移效应，从而增加传输过程中传播信道中的衰落水平。因此，在本文中，我们研究了由呼吸引起的无线体域网 (WBAN) 的两个节点之间的相对运动对传播信道的频率影响，其中至少一个节点位于人体内部. 该研究是在形状拟合和频率扩展参数推导方面的多普勒频谱特征的基础上进行的。