Joint minimization of uplink and downlink whole-body exposure dose in indoor wireless networks
Plets D, Joseph W, Vanhecke K, Vermeeren G, Wiart J, Aerts S, Varsier N, Martens L. Joint minimization of uplink and downlink whole-body exposure dose in indoor wireless networks. Biomed Res Int. 2015;2015:943415. doi: 10.1155/2015/943415. Epub 2015 Feb 22.
The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS) configuration for phone call traffic, and a Long-Term Evolution (LTE) configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism.
Conclusions and Future Work
In this paper, total whole-body exposure doses (uplink and downlink) are jointly minimized for indoor wireless network deployments. The mathematical formulation has been given and four simulation scenarios were proposed: two WiFi configurations with a different throughput requirement, one UMTS voice call scenario, and one LTE high-throughput scenario. For WiFi, downlink doses are reduced by more than 95% by the optimized deployment. Due to the lack of power control, uplink usages of only a few seconds suffice to make the uplink dose higher than the downlink dose, limiting the reductions of the optimized deployment for longer uplink usages. Deployments with lower WiFi throughputs benefit less from optimizing the access point configuration. For UMTS, total dose reductions vary between 73% and 83%, irrespective of the uplink usage, thanks to the power control mechanism. For the LTE configuration with high-power base stations, dose reductions are at least 80% and increase for higher uplink usages. For UMTS and LTE, an almost continuous uplink usage is required to induce a significant effect on the total dose, again thanks to the power control mechanism.
In future research, the influence of the uplink transmission of other users will be accounted for and localized doses will be calculated. Also, a technoeconomic analysis will be done to link the (lower) exposure to the (higher) network installation cost, and the influence of the number of users and their usage profiles on the actual duty cycle of an access point will be investigated.
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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