Joint User Association and Spectrum Allocation for Small Cell Networks With Wireless Backhauls

Heterogenous networks and massive MIMO can significantly enhance spectral and energy efficiencies of wireless networks and have recently attracted lots of attention. In this letter, we investigate joint user association and spectrum allocation to further improve spectral efficiency for massive MIMO enabled heterogeneous networks with full-duplex wireless backhauls. The optimization problem is formulated as a mixed-integer nonlinear programming problem, and therefore, is nonconvex and combinational. To solve the problem efficiently, the original optimization problem is divided into two sub-problems that can be solved with low-computational-complexity methods. The simulation results confirm our theoretical analysis and demonstrate the performance improvement of the proposed algorithm.