## 1 Introduction  
The rapid introduction of fifth generation (5G) mobile networks is causing major public concern. Notably, the use of new frequency bands below and above 6 GHz, as well as the need for a denser base station infrastructure, and the proposed waiving of or reduction in precautionary limits in some countries are intensifying the debate. Frequency bands above 6 GHz will be opened for 5G, which require additional risk assessment research [1; 2; 3; 4; 5; 6]. However, the first 5G network installations will make use only of frequencies below 6 GHz, the frequency range that has been utilized for wireless communications for the past two decades. Nevertheless, there is very little practical and theoretical knowledge about the expected exposure from upcoming 5G networks in this frequency range. In addition, the most recent studies on the analysis of human exposure to mobile communication networks focus either on the exposure from an individual's mobile device [7; 8] or the base station network [9] separately. There are various recent studies [10; 11; 12; 13; 14; 15] that have been published, aimed at the optimization of wireless networks with respect to energy efficiency, and human exposure. From those studies, only [12] analyses the network infrastructure for the exposure to uplink signals from mobile devices. On the other hand, [12] does not consider different usage patterns or attempts to combine uplink, downlink, and bystander exposure. However, in modern, highly dynamic and adaptive networks, the mobile device, the network, and the data usage cannot be regarded as standalone when evaluating the total dose.  
In this study, we investigate the combined dose from a user's mobile device and the surrounding base station network for various usage scenarios, user locations, and network topologies. As there is very little reliable data on the performance behavior of 5G networks in real implementations to date, we extrapolated performance behavior from measured 4 th generation (4G) Long Term Evolution (LTE) mobile network data. Based on inputs from Swiss mobile operators, their performance targets for 5G networks are to provide data rates of 100 MBit/s everywhereand 3 GBit/s in peak locations. It is important to note that the everywhere requirement is a factor of about 10-20 higher than that for current LTE networks. This study is not designed to allow conclusions to be drawn about absolute levels of exposure, but rather to differentially evaluate the various scenarios of 5G networks. Other sources of exposure, e.g., wireless local area network (WLAN), radio, and television (TV) broadcast, etc., are excluded. Most 5G networks will rely on a hybrid network topology. Therefore, one focus of this study is on the effect on the total dose of the percentage of indoor cells used in such a hybrid network. This study is based on the supposition that the network topologies can be achieved; we do not look into how network coverage will be realized.  
In summary, the overall objective of this study is to evaluate total human exposure in hypothetical 5G networks for different topologies and user scenarios and to identify factors that minimize the total exposure of the population.