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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 - Biomed Res Int (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Information Technology Department, Ghent University/iMinds, Gaston Crommenlaan 8, 9050 Ghent, Belgium.

ABSTRACT
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.

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CDF of total dose (uplink + downlink) within one hour for scenario 1 for traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time).
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fig3: CDF of total dose (uplink + downlink) within one hour for scenario 1 for traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time).

Mentions: Figure 3 shows the cumulative distribution function (cdf) of the whole-body doses over a time frame of one hour for the traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time) for WiFi with a downlink throughput of 54 Mbps. It also shows the median whole-body dose reductions when switching from a traditional to an exposure-optimized configuration. The mobile device is held in front of the body. The “0% UL” cdfs correspond with the DL-only dose. Table 2 shows the 50% and 95% percentile of the doses for the different configurations of scenario 1. Figure 3 and Table 2 show that the downlink dose (0% UL) is drastically lowered in the exposure-optimized deployment (higher number of BS with a lower EIRP): a reduction of the median (Dwb-total50), from 2.2 · 10−4 to 3.1 · 10−6 J/kg (reduction of 98.6%) and a reduction of 99.4% for the 95% percentile (Dwb-total95) of the total dose. For the WiFi scenario, both configurations (traditional and optimized) will cause the same uplink powers and uplink doses due to the absence of power control in WiFi devices: irrespective of the connection quality with the AP, a fixed power of 20 dBm is assumed. Figure 3 and Table 2 show that, as the uplink usage increases (from 0 to 10 to 100%), the total dose is becoming quickly dominated by the uplink dose. For example, when comparing a usage of 10% with DL-only (0% usage), the median of the total dose (Dwb-total50) is 24 times higher for the traditional deployment (0.0053 versus 2.22 · 10−4) and 1618 times higher for the optimized deployment (0.005 versus 3.09 · 10−6). The increasing dominance of the uplink causes the median dose reductions to become gradually smaller: from 98.6% for DL-only to 4.2% and 0.4% for 10% and 100% usage, respectively (see %RED in Table 2 and in Figure 3). The small dose reductions for an UL usage of 100% correspond to the almost coinciding plots for the traditional and optimized configurations. Unlike the median, the 95% percentile (highest doses) is still significantly reduced (46.6%) when using the optimized configuration with a 10% UL usage.


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 - Biomed Res Int (2015)

CDF of total dose (uplink + downlink) within one hour for scenario 1 for traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4352489&req=5

fig3: CDF of total dose (uplink + downlink) within one hour for scenario 1 for traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time).
Mentions: Figure 3 shows the cumulative distribution function (cdf) of the whole-body doses over a time frame of one hour for the traditional and optimized deployment for three uplink usages (0%, 10%, and 100% of the time) for WiFi with a downlink throughput of 54 Mbps. It also shows the median whole-body dose reductions when switching from a traditional to an exposure-optimized configuration. The mobile device is held in front of the body. The “0% UL” cdfs correspond with the DL-only dose. Table 2 shows the 50% and 95% percentile of the doses for the different configurations of scenario 1. Figure 3 and Table 2 show that the downlink dose (0% UL) is drastically lowered in the exposure-optimized deployment (higher number of BS with a lower EIRP): a reduction of the median (Dwb-total50), from 2.2 · 10−4 to 3.1 · 10−6 J/kg (reduction of 98.6%) and a reduction of 99.4% for the 95% percentile (Dwb-total95) of the total dose. For the WiFi scenario, both configurations (traditional and optimized) will cause the same uplink powers and uplink doses due to the absence of power control in WiFi devices: irrespective of the connection quality with the AP, a fixed power of 20 dBm is assumed. Figure 3 and Table 2 show that, as the uplink usage increases (from 0 to 10 to 100%), the total dose is becoming quickly dominated by the uplink dose. For example, when comparing a usage of 10% with DL-only (0% usage), the median of the total dose (Dwb-total50) is 24 times higher for the traditional deployment (0.0053 versus 2.22 · 10−4) and 1618 times higher for the optimized deployment (0.005 versus 3.09 · 10−6). The increasing dominance of the uplink causes the median dose reductions to become gradually smaller: from 98.6% for DL-only to 4.2% and 0.4% for 10% and 100% usage, respectively (see %RED in Table 2 and in Figure 3). The small dose reductions for an UL usage of 100% correspond to the almost coinciding plots for the traditional and optimized configurations. Unlike the median, the 95% percentile (highest doses) is still significantly reduced (46.6%) when using the optimized configuration with a 10% UL usage.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Information Technology Department, Ghent University/iMinds, Gaston Crommenlaan 8, 9050 Ghent, Belgium.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus