Minimizing the exposure dose of Multi-Antenna Multi-Carrier System Users

The impact of multi-antenna wireless personal devices (WPDs) on the electromagnetic field (EMF) exposure of users has yet to be properly understood at the system level. In this paper, we first explain how to model the exposure dose of multi-antenna WPD users in a multi-user multi-carrier communication system. This model is then used for minimising the exposure dose, when considering the quality of service (QoS) as well as transmit power requirements. In the process, we identify a new criterion, i.e. the ratio between the normalised exposure dose and the channel to noise ratio, as the main optimisation criterion for reducing the exposure dose of WPD users. Simulation results show that the usage of multi-antenna transmission can significantly reduce the exposure dose of WPD users in a multi-carrier system. An exposure reduction of at least 55% is achieved when a two-transmit WPD is used instead of a single antenna WPD, while ensuring QoS.