Joint User Association and Power Allocation in Multi-connectivity Enabled mmWave Networks: a Perspective of Rate Trade-off among Users

The multi-connectivity enabled user association (MCUA) represents a promising technology to overcome the unreliability of millimeter-wave (mmWave) links, which are plagued by severe path loss, frequent cross-cell handover, and vulnerability to blockage by obstacles. This paper aims to address the essential challenges in MCUA, i.e., the user associations and power allocations. Specifically, we investigate the joint optimization of MCUA and power allocation from the perspective of the trade-off between downlink rates for different users, taking into account the mutual constraints on each user's downlink rate in resource-limited systems. To solve this nonlinear mixed integer multi-objective optimization problem, we first employ the weighted-sum method to scalarize it as a single-objective optimization problem (SOOP) and relax the binary association variables to real ones. Then we develop an iterative algorithm based on the convex-concave procedure to solve this relaxed SOOP. Numerical results are presented to demonstrate the effectiveness of the proposed algorithms.