User Selection and Power Allocation in Full-Duplex Multicell Networks

Full-duplex (FD) communications has the potential to double the capacity of a half-duplex (HD) system at the link level. However, in a cellular network, FD operation is not a straightforward extension of HD operations. The increased interference due to a large number of simultaneous transmissions in FD operation and real-time traffic conditions limits the capacity for improvement. Realizing the potential of FD requires careful coordination of resource allocation among the cells, as well as within the cell. In this paper, we propose a distributed resource allocation, i.e., joint user selection and power allocation for an FD multicell system, assuming FD base stations (BSs) and HD user equipment (UE). Due to the complexity of finding the globally optimum solution, a suboptimal solution for UE selection and a novel geometric-programming-based solution for power allocation are proposed. The proposed distributed approach converges quickly and performs almost as well as a centralized solution but with much lower signaling overhead. It provides a hybrid scheduling policy that allows FD operations whenever it is advantageous, but otherwise, it defaults to HD operation. We focus on small-cell systems because they are more suitable for FD operation, given practical self-interference cancelation limits. With practical self-interference cancelation, it is shown that the proposed hybrid FD system achieves nearly twice the throughput improvement for an indoor multicell scenario and about 65% improvement for an outdoor multicell scenario, compared with the HD system.