Toward energy efficient and balanced user associations and power allocations in multi-connectivity enabled mmWave networks

The mmWave spectrum has been involved in the 5G wireless communication systems for its enormous spectrum resources. However, signals over mmWave bands suffer from severe path loss and are vulnerable to be blocked by obstacles due to the extremely high frequency. Multiconnectivity technology is a promising way to overcome the shortage, which allows one user to associate with multiple mBSs simultaneously. Two essential challenges still exist in multiconnectivity enabled mmWave networks. The first one is to establish optimal user associations. The second one is to optimize power allocation for each connection. Considering the aforementioned challenges, a multi-objective optimization problem was proposed, which aimed to jointly optimize the UA and PA in multiconnectivity enabled mmWave networks. Distinguished from most existing works, the optimization objectives in this paper include maximizing the overall energy efficiency, meanwhile balancing the achievable rates among all users and the traffic load among all mBSs under QoS constraints, respectively. A novel Multi-Objective Harris Hawk Optimization (MOHHO) algorithm based approach was designed to obtain near-optimal solutions. Simulation results demonstrate that the proposed scheme can achieve good performance with overall energy efficiency, fairness of user rate and balance of mBSs traffic load.