good
Because this paper conducted experiments in real world apartments to study the impact of
interference on wireless networks, the observations it found should be more applicable to real-
world environments compared with the study using simulations. The drawback of using real
homes is that it is time-consuming and costly. Thus, the paper can only collect data from limited
number of homes and time periods. Nontheless, the conclusions and findings of this paper are
still very valuable. For example, it found that the commonly-held assumption that channel 26
will be open is not true in the real-world situation. Only careful study on real world like this
paper can have such kind of findings.
The methods of data analysis in this paper were well-considered. For example, to investigate
spectrum usage change with time, it computed the standard deviation of occupancy using
various time periods: day-to-day, hour-to-hour and every 5 minutes. By considering both long
and short time scale, the conclusion that there is significant variability over time for spectrum
occupancy was supported much more strongly.
Although, overall the quality of analysis in this paper is very good, some aspects are not fully
investigated. For example, in the analysis of Wi-Fi interference, the paper claimed there are
other non-negligible interferences apart from Wi-Fi, but it didn’t investigated what they are
concretely. It should investigated why the situations in apartment 4 and apartment 5 are
different from others as indicated in the Figure 5 of the paper.
This paper had many insightful findings about HAN, a natural extension and improvement of
this paper is to address how we solve the problems found and apply the knowledge learned
such as HAN design that can decrease the interferences Wi-Fi and other sources and the
combination of channel.