IEEE Consumer Electronics Magazine - July/August 2023 - 91

TABLE 4. Comparison of traditional standards and NRSDex in the case study.
Item
Traditional Standards
Local
limits
Other countries'
limits
Device A Qualified Qualified
Device B Qualified Not Qualified
Discussion
Device B fulfills local limits but
does not satisfy other countries'
limits, confusing the public
about whether device B should
be selected. Besides, the
specific difference between
Device A and B cannot be found.
Power density
level
5
3
1Device A: 4.13
2Device B: 3.26
Conclusion: Device B has a NRSDex score higher than 3, implying
that it can be selected but should still be further improved. Device
A has better performance on radiation power density level and
radiation body region.
1NRSDex A ¼ 539.33%þ325.84%þ434.84% ¼ 4.13.
2NRSDex B ¼ 339.33%þ425.84%þ334.84% ¼ 3.26.
Example A of Attribute A is calculated as 3). By
analyzing all the examples from the same attribute,
the range of the preference level on each
attribute could be obtained. The weightings can
be calculated by normalizing these ranges.
Case Study
The radiation from heart rate monitoring devices
affects on human heart, and thus deserves
extra focus. In this case study, consider two types
of heart rate monitoring devices, namely Device A
and Device B, which are both well designed with
satisfactory radiation levels to fulfill the local standard,
as illustrated in Table 4. If standards of other
countries are utilized to examine them, it is found
that Device A fulfills all local NIR safety standards
and global ones but Device B is not satisfactory,
which confuses the public about whether Device
B can be a candidate to be selected. Besides, it is
hard to distinguish their differences in radiation
safety using traditional standards.
NowNRSDex is applied. As mentioned, product
scores of power density levels are 5 and 3. Regarding
the exposure time to NIR, Device A has a larger
duty cycle, and the scores are 3 and 4, respectively.
Besides, Device A is designed as a watch to be
worn on the wreck, while Device B needs to be
deployed on the neck. As a result, scores of the
attribute exposed human body regions are 4 and 3,
respectively. Then, the weightings for three attributes
are evaluated. Considering heart monitoring
device, which works proximate to the human
body, it is believed that the power density level is
the most important attribute and the exposed
July/August 2023
humanbodyregions follow. Usingthe conjoint
analysis, the weightings are estimated as 39.33%,
25.84%, and 34.83%. The weighting allocation
scheme illustrates that a higher NRSDex level can
be obtained by improving the performance of
power density level and exposed human body
regions. With the weighting allocation scheme and
the scores for three attributes, the final NRSDex for
Device A and B are calculated as 4.13 and 3.26.
According to the evaluation results, it can be concluded
that Device B still can be selected with
NRSDex score higher than 3, despite it needs to be
further improved on its radiation power density
level and radiation body region. Besides, Device A
has a better NIR safety performance with NRSDex
score higher than 4.
FUTURE DIRECTIONS
Three future directions are identified and
discussed.
Long-haul transmission: Long-haul transmission
frequently delivers high transmission power
due to the weak link budget, thus increasing the
radiation risk. As a result, when there is a longhaul
transmission, excessive radiation must be
avoided. Potential research areas to mitigate the
challenge include resource allocation strategies
that tradeoff the transmission range and radiation
risk, adaptive communication scheduling strategies
that create suitable duty cycles to avoid outof-range
radiation, etc.
High concentration radiation environment: A
single device that conforms to safety regulations
91
3
4
NRSDex
Exposure time to
NIR
4
3
Exposed human body
regions
IEEE Consumer Electronics Magazine - July/August 2023

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - July/August 2023
