Mitigation of Human RF Exposure in Wearable Communications

Abstract

A major concern regarding wearable communications is human biological safety under exposure to radio frequency (RF) radiation generated by wearable devices. The biggest challenge in the implementation of wearable devices is to reduce the usage of energy to minimize the harmful impacts of exposure to RF on human health. Power management is one of the key energy-saving strategies used in wearable networks. Signals enter the receiver (Rx) from a transmitter (Tx) through the human body in the form of electromagnetic field (EMF) radiation produced during the transmission of the packet. It may have a negative effect on human health as a result of specific absorption rate (SAR). SAR is the amount of radio frequency energy consumed by human tissue in mass units. The higher the body's absorption rate, the more radio frequency radiation. Therefore, SAR can be reduced by distributing the power over a greater mass or tissue volume equivalently larger. The Institute of Electrical and Electronics Engineers (IEEE) 802.15.6-supported multi-hop topology is particularly useful for low-power embedded devices that can reduce consumption of energy by communicating to the receiver (Rx) through nearby transmitted devices. In this paper, we suggest a relaying mechanism to minimize the transmitted power and, as a consequence, the power density (PD), a measure of SAR.Index Terms-Wearable communications; Human RF exposure; SAR; PD; WBAN; multi-hop communications; 2.4 GHz • Second, using multi-hop communication in IEEE 802.15.6 standard the power density reduction by using a relaying method has been depicted.• Third, a new protocol has been proposed where the relay transmission power has been reduced to a certain extent so that the data rate ultimately becomes almost similar to that of direct connection without relay. II. RELATED WORKHuman EMF exposure in wireless communications garnered significant interest in recent literature. This section describes the state-of-the-art on characterization and reduction of EMF exposure in recent communications technologies. A. EMF Exposure in Recent Wireless TechnologiesNot only in wearable communications, other recent wireless technologies were also discussed on the human EMF exposure such as 5G [24]- [27]. The key finding from the prior works is that not only the uplink, but the downlink can also cause higher human EMF exposure compared to previous-generation. The

Analysis of Human Exposure to Electromagnetic Fields in 5G Uplink and Downlink

“…PD and SAR are the two most widely accepted metrics to measure the intensity and effects of EMF exposure [6]. The FCC suggests PD as a metric measuring the human exposure to EMF generated by devices operating at frequencies higher than 6 GHz [4], whereas a recent study suggested that a guideline defined in PD is not efficient to determine the impacts on health issues especially when devices are operating extremely close to the human body such as in an uplink [6]- [13].…”