Spectral and Energy Efficient Power Allocation for MIMO Broadcast Channels with Individual Delay and QoS Constraints

In this paper, we propose a novel power allocation algorithm to maximize the spectral efficiency (SE) and energy efficiency (EE) of multiple-input multiple-output (MIMO) broadcast channels under individual quality of service (QoS) constraints. In several wireless applications, one of the most important factors for QoS guarantee is delay outage. To address the impact of delay outage occurring in the link layer, effective capacity (EC) that means the maximum constant arrival rate satisfying statistical delay-QoS constraint is considered. Using a novel performance metric, effective-EE, which is defined as EC divided by total power consumption, we formulate an EC and effective-EE maximization problem with QoS constraints as an adaptive power allocation problem. By applying Lagrangian method, we solve optimization problem and propose an optimal power allocation algorithm. Simulation results demonstrate that our proposed algorithm can improve the EC and effective-EE performance.