Coalition game for user association and bandwidth allocation in ultra-dense mmWave networks

In future layered fifth generation (5G) wireless networks, a large number of millimeter-wave (mmWave) small cells will be covered by a microwave macrocell, where radio access links to a small cell and the backhaul link to its macrocell share a common mmWave bandwidth, which is called wireless self-backhauling. One of the major challenges in self-backhauling ultra-dense networks (UDNs) is the optimization of user association and resource allocation between the radio access links and backhaul links, which is essential to improve the network performance. This paper proposes a coalition game based joint user association and bandwidth allocation algorithm for ultradense mmWave networks (UDMNs), in which users form a set of coalitions by playing coalition games to maximize network sum rate and make the downlink traffic of small cells in current cell association period be accommodated by their wireless backhaul. Simulation results show that, the proposed scheme improves the sum rate significantly compared to the traditional minimum-distance based user association scheme, and approximates the performance of immune optimization algorithm (IOA) in terms of sum rate and has much lower computational complexity.