Research Report RR-13-286
Operators have recently resorted to WiFi offloading to deal with increasing
data demand and induced congestion. Researchers have further suggested
the use of "delayed offloading": if no WiFi connection is available, (some)
traffic can be delayed up to a given deadline, or until WiFi becomes available.
Nevertheless, there is no clear consensus as to the benefits of delayed
offloading, with a couple of recent experimental studies largely diverging in
their conclusions. Nor is it clear how these benefits depend on network characteristics
(e.g. WiFi availability), user traffic load, etc. In this paper, we propose
a queueing analytic model for delayed offloading, and derive the mean
delay, offloading efficiency, and other metrics of interest, as a function of the
user's "patience", and key network parameters. We validate the accuracy of
our results using a range of realistic scenarios, and use these expressions to
show how to optimally choose deadlines.