  The unprecedented growth of mobile data traffic challenges the performance
and economic viability of today's cellular networks, and calls for novel
network architectures and communication solutions. Data offloading through
third-party WiFi or femtocell access points (APs) can effectively alleviate the
cellular network congestion in a low operational and capital expenditure. This
solution requires the cooperation and agreement of mobile cellular network
operators (MNOs) and AP owners (APOs). In this paper, we model and analyze the
interaction among one MNO and multiple APOs (for the amount of MNO's offloading
data and the respective APOs' compensations) by using the Nash bargaining
theory. Specifically, we introduce a one-to-many bargaining game among the MNO
and APOs, and analyze the bargaining solution (game equilibrium) systematically
under two different bargaining protocols: (i) sequential bargaining, where the
MNO bargains with APOs sequentially, with one APO at a time, in a given order,
and (ii) concurrent bargaining, where the MNO bargains with all APOs
concurrently. We quantify the benefits for APOs when bargaining sequentially
and earlier with the MNO, and the losses for APOs when bargaining concurrently
with the MNO. We further study the group bargaining scenario where multiple
APOs form a group bargaining with the MNO jointly, and quantify the benefits
for APOs when forming such a group. Interesting, our analysis indicates that
grouping of APOs not only benefits the APOs in the group, but may also benefit
some APOs not in the group. Our results shed light on the economic aspects and
the possible outcomes of the MNO/APOs interactions, and can be used as a
roadmap for designing policies for this promising data offloading solution.
