IEEE Trans Biomed Circuits Syst. 2011 Aug;5(4):307-19. doi: 10.1109/TBCAS.2011.2160060.
We investigate the use of relaying of creeping waves in the industrial scientific medical frequency bands of 434 MHz, 915 MHz, and 2.4 GHz. The investigation includes generic analysis and experimental setups. For generic analysis, a link budget model is derived based solely on the creeping wave component of the transmitted signal while marginalizing for other effects, such as reflections from the surrounding environment. Closed-form expressions of the gains in network lifetime and energy per bit are derived for a system covering the entire body using relays compared to a reference system offering the same level of reliability without relaying. The experimental setups are used to gather measurements in the 2.4-GHz band with a body sensor network development platform in a nonreflective open-space environment and in a reflective residential environment. The measurements are used to validate the link budget model and evaluate performance of practical systems. Analysis and experimentation demonstrate that relaying of creeping waves offers considerable performance gains in all frequency bands. For example, using a single relay on either side of the body in 2.4 GHz can potentially increase network-lifetime times 40 and decrease energy per bit by 48 dB. Part of this potential is achieved in experimental setups where relaying was shown to increase network lifetime times 13, decrease energy per bit by 13 dB and provide the ability to compensate for a wider fading margin.
我们研究了在工业、科学和医疗频段（434MHz、915MHz 和 2.4GHz）中使用爬波中继的情况。该研究包括一般性分析和实验设置。对于一般性分析，我们基于传输信号的爬波分量推导了链路预算模型，同时忽略了周围环境反射等其他影响。针对使用中继覆盖整个身体的系统与不使用中继但提供相同可靠性水平的参考系统相比，我们推导出了网络寿命和每比特能量增益的闭式表达式。实验设置用于在非反射开放空间环境和反射居住环境中使用 2.4GHz 频段的身体传感器网络开发平台进行测量。测量结果用于验证链路预算模型并评估实际系统的性能。分析和实验表明，在所有频段中，爬波中继都能带来相当大的性能提升。例如，在 2.4GHz 频段中，在身体的每一侧使用单个中继，就有可能将网络寿命提高 40 倍，并将每比特能量降低 48dB。在实验设置中，部分潜在增益得以实现，中继可将网络寿命提高 13 倍，将每比特能量降低 13dB，并提供补偿更大衰落裕度的能力。
