Does Multi-Hop Communication Reduce Electromagnetic Exposure?

Widespread concerns about potential health hazards caused by electromagnetic exposure have been raised in many countries. Although there is no ultimate consensus on radiation power levels and their respective impacts on human health, methods are necessary to reduce exposure as much as possible because of the rapid deployment of wireless communications systems. In our work we scrutinize the exposure reduction potential of the multi-hopping approach for two standardized but different wireless network types: IEEE 802.11b as a representative example for networks with distributed channel access control and HIPERLAN/2 as a representative example for centrally controlled networks. Our results show that multi-hopping has the potential to reduce the received electro magnetic power and energy for both network types although it suffers from a decreased network capacity. When attempting to compensate for this decrease by adapting the data rate used over an individual link, the ensuing transmission power adaptation required to maintain acceptable error rates does not necessarily neutralize the benefit of multi-hopping. We show that the sophisticated use of multi-hopping in conjunction with data rate adaption positively affects the received electromagnetic power and energy.