  Carrier aggregation, which allows users to aggregate several component
carriers to obtain up to 100 MHz of band- width, is one of the central features
envisioned for next generation cellular networks. While this feature will
enable support for higher data rates and improve quality of service, it may
also be employed as an effective interference mitigation technique, especially
in multi-tier heterogeneous networks. Having in mind that the aggregated
component carriers may belong to different frequency bands and, hence, have
varying propagation profiles, we argue that it is not necessary, indeed even
harmful, to transmit at maximum power at all carriers, at all times. Rather, by
using game theory, we design a distributed algorithm that lets eNodeBs and
micro base stations dynamically adjust the downlink transmit power for the
different component carriers. We compare our scheme to different power
strategies combined with popular interference mitigation techniques, in a
typical large-scale scenario, and show that our solution significantly
outperforms the other strategies in terms of global network utility, power
consumption and user throughput.
