Coordinated Link Adaptation for an Energy-Efficient Full-Duplex Random Access Network

In this paper, we develop a coordinated link adaptation scheme to maximize the energy efficiency of a full-duplex (FD) random access network when self-interference cancellation (SIC) is imperfect. First, we model the energy consumption of an FD link and formulate an energy-consumption-per-bit minimization problem with the constellation size of the link as a problem variable. Via numerical results, the model shows that the optimal constellation size of an FD link strongly depends on not only the communication distance but also the SIC capability and data length. Then, we extend the formulation to the energy-consumption minimization problem for an FD random access network. A conservative delay budget for saturated traffic conditions is obtained in terms of the constellation sizes of the associated devices. Finally, the network coordination problem for the constellation sizes is formulated as a nonlinear problem with integer constraints on the constellation sizes, and a solution algorithm for this problem is designed, employing the successive convex approximation method. A comparative evaluation with representative conventional schemes demonstrates that the proposed scheme significantly outperforms the conventional schemes in terms of the energy consumption per bit for a wide range of network environments.