  Given the proven benefits cell densification brings in terms of capacity and
coverage, it is certain that 5G networks will be even more heterogeneous and
dense. However, as smaller cells are introduced in the network, interference
will inevitably become a serious problem as they are expected to share the same
radio resources. Another central feature envisioned for future cellular
networks is carrier aggregation (CA), which allows users to simultaneously use
several component carriers of various widths and frequency bands. By exploiting
the diversity of the different carriers, CA can also be used to effectively
mitigate the interference in the network. In this paper, we leverage the above
key features of next-generation cellular networks and formulate a downlink
power setting problem for the different available carriers. Using game theory,
we design a distributed algorithm that lets cells dynamically adjust different
transmit powers for the different carriers. The proposed solution greatly
improves network performance by reducing interference and power consumption,
while ensuring coverage for as many users as possible. We compare our scheme to
other interference mitigation techniques, in a realistic large-scale scenario.
Numerical results show that our solution outperforms the existing schemes in
terms of user throughput, energy and spectral efficiency.
