Thursday, January 08, 2015

The LEXNET Project: Wireless Networks and EMF: Paving the Way for Low-EMF Networks of the Future

The LEXNET Project: Wireless Networks and EMF: Paving the Way for Low-EMF Networks of the Future

Tesanovic, M.  Conil, E. ; De Domenico, A. ; Aguero, R. et al. The LEXNET Project: Wireless Networks and EMF: Paving the Way for Low-EMF Networks of the Future. IEEE Vehicle Technology Magazine. IEEE. Vol. 9(2):20-28. June, 2014.

While, according to the World Health Organization, no adverse health effects of radio-frequency (RF) electromagnetic fields (EMFs) have been established to date, EMF exposure from wireless communication networks is nonetheless often cited as a major cause of public concern and is frequently given considerable media coverage. This article presents the results of a new survey on RF-EMF exposure risk perception together with a comprehensive overview of the EMF footprint of existing and emerging networks. On the basis of these findings, we then put forward the rationale for EMF-aware networking. Subsequently, we highlight the gaps in existing systems, which impede EMF-aware networking, and outline the key concepts of the recently launched European Union (EU) Seventh Framework Programme (FP7) Integrated Project Low-EMF Exposure Future Networks (LEXNET): a new, all-encompassing, population-based metric of exposure and ways it can be used for low-EMF, quality of service (QoS)-aware network optimization.


As the Eurobarometer Study [1] indicates, public concern about EMF exposure is quite stable: an astonishing 46% of Europeans are still concerned or very concerned about EMF health risks, without, however, distinguishing between various sources of EMF (e.g., access points versus hand-held devices) and their relative contribution to the overall exposure ...

From this brief consideration, three important questions emerge: What are the different sources of exposure? Which factors determine the strength of exposure in
the eyes of the public?  How do people link exposure to risk?

To study these issues, we conducted an in-depth survey, and we report here some of its key findings. Data were collected from April to May 2013 in France, Germany, Portugal, and Spain using an online survey tool. A total of 1,978 respondents participated in this survey (mean age: 36 years; gender distribution: 60% female and 40% male).

Regarding the perceived health hazards of various usage scenarios, our respondents evaluated base stations on a school roof as the most dangerous (see Figure 1). On a five-point Likert scale (1 = not dangerous, and 5 = very dangerous), the mean score of a base station is 3.35. Using a mobile phone for calls is perceived as less dangerous, averaging a mean of 2.87. A somewhat lower score characterizes a laptop used on the lap; here, the mean danger perception is 2.63.

This finding is consistent with the perception of exposure strength due to various EMF sources (given in Figure 2). The respondents had to evaluate them on a five-point Likert scale. Figure 2 clearly indicates that base stations are seen as the strongest EMF exposure source (mobile communication masts: mean = 3.86; followed by microwave ovens: mean = 3.31; and mobile phones: mean = 3.21).

Finally, a regression analysis of various exposure scenarios on health concerns demonstrates that the distance to the exposure source is not a significant predictor of these concerns, as evidenced by the values of regression coefficients given in Table 1. Significant predictors are shown to be the number of exposure sources, the duration of the exposure, and the frequency of exposure.

The above results indicate that the risk perceptions of the general public and the underlying health concerns are guided by subjective models of EMF impact, which underestimate near-field exposure and overestimate far-field exposure. People are more concerned about base stations than about all other RF-EMF sources. This distortion may explain why the exposure incurred by personal EMF-emitting devices such as laptops and cell phones is not a key factor in public risk perception.

This article presented an overview of how the deployment of existing and emerging wireless networks impacts the resulting EMF levels. Attention has been drawn to the fact that the main focus of the existing EMF exposure evaluation framework is conformance testing using worst-case scenarios, in which wireless network equipment and mobile terminals transmit at maximum power levels. The mounting worries about the exposure of end users to EMFs could change the users’ view of QoS, making EMF exposure an integral part of day-to-day network performance. What is more, the mechanics of this high-QoS versus low-EMF tradeoff are different for different applications, services, and usage scenarios. From the provided state-of-the-art overview, a clear need has surfaced for low-EMF, QoSaware
networking, which LEXNET will tackle.

In particular, LEXNET will focus on developing novel radio-link technologies and incorporating them into deployment of adaptive, self-organizing network topologies and intelligent positioning of access points, with a view to reducing the EMF exposure while maintaining the QoS. Novel techniques are needed for the management of new and the existing network topologies whereby the EMF exposure is optimized jointly with the QoS. As has been demonstrated, the existing network engineering services are very limited in this respect, and the main challenge is therefore to include EMF into the optimization process by designing and implementing a population-based exposure metric, the exposure index, that takes into account exposure due to both personal devices and network transmitters.
It is important to stress that LEXNET is not redefining safety limits or reevaluating the effects of RF-EMF on human health. All of the techniques LEXNET is developing are compliant with existing safety regulations. The uniqueness of the LEXNET approach is that it builds upon existing metrics by introducing the novel exposure index to quantify population exposure. This will enable the development of network management technologies that reduce EMF exposure without compromising the user QoS.

[1] TNS Opinion & Social. (2010, June). Eurobarometer 73.3, Electromagnetic fields. [Online].

Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

Electromagnetic Radiation Safety

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