The serial number of the access point that reported an
RSS value for the station. This object is meaningful only when
the value of etsysTrackedStationLocationType is cellOfOrigin. The
cell of origin method determines location based on the probable
distance of the subject from a known location, in this case, the
location of the AP that reported the RSS value. Cell of Origin is
used when fewer than three APs report seeing the station at one
time. If two APs report the station then the serial number
of the AP reporting the strongest RSS is reported as the
station's etsysTrackedStationReportingAPSN.