With the development of fifth-generation (5G) networks, the number of user equipments (UE) increases dramatically. However, the potential health risks from electromagnetic fields (EMF) tend to be a public concern. Generally, EMF exposure-related analysis mainly considers the passive exposure from base stations (BSs) and active exposure that results from the user's personal devices while communicating. However, the passive radiation that is generated by nearby devices of other users is typically ignored. In fact, with the increase in the density of UE, their passive exposure to human bodies can no longer be ignored. In this work, we propose a stochastic geometry framework to analyze the EMF exposure from active and passive radiation sources. In particular, considering a typical user, we account for their exposure to EMF from BSs, their own UE, and other UE. We derive the distribution of the Exposure index (EI) and the coverage probability for two typical models for spatial distributions of UE, i.e., \textit{i)} a Poisson point process (PPP); \textit{ii)} a Matern cluster process. Also, we show the trade-off between the EMF exposure and the coverage probability. Our numerical results suggest that the passive exposure from other users is non-negligible compared to the exposure from BSs when user density is $10^2$ times higher than BS density, and non-negligible compared to active exposure from the user's own UE when user density is $10^5$ times the BS density.

翻译：随着第五代（5G）网络的发展，用户设备（UE）数量急剧增加。然而，电磁场（EMF）带来的潜在健康风险逐渐成为公众关注的问题。通常，EMF暴露相关分析主要考虑来自基站（BS）的被动暴露以及用户通信时个人设备产生的主动暴露。然而，其他用户附近设备产生的被动辐射通常被忽略。实际上，随着UE密度的增加，它们对人体的被动暴露已不可忽视。本文提出了一种随机几何框架，用于分析来自主动和被动辐射源的EMF暴露。特别地，针对典型用户，我们考虑了其来自BS、自身UE以及其他UE的EMF暴露。我们推导了暴露指数（EI）的分布以及覆盖概率，针对两种典型的UE空间分布模型：i）泊松点过程（PPP）；ii）Matern聚类过程。同时，我们展示了EMF暴露与覆盖概率之间的权衡。数值结果表明，当用户密度是BS密度的$10^2$倍时，来自其他用户的被动暴露与来自BS的暴露相比不可忽略；当用户密度是BS密度的$10^5$倍时，该被动暴露与用户自身UE的主动暴露相比也不可忽略。