  Delayed offloading is a widely accepted solution for mobile users to offload
their traffic through Wi-Fi when they are moving in urban areas. However,
delayed offloading enhances offloading efficiency at the expense of delay
performance. Previous works mainly focus on the improvement of offloading
efficiency while keeping delay performance in an acceptable region. In this
paper, we study the impact of the user mobility on delayed data offloading in
respect to the tradeoff between offloading efficiency and delay performance. We
model a mobile terminal with delayed data offloading as an M/MMSP/1 queuing
system with three service states. To be practical, we consider the feature of
currently commercial mobile terminals in our analysis. Our analytical result
shows that the mobility of the users can reduce the queueing delay incurred by
the delayed offloading, and suggests that delayed offloading strategies can be
optimized according to the mobility of the terminals once the delay requirement
is given.
