Uplink power allocation schemes for heterogeneous cellular networks

With the increasing number of small cell nodes, the power consumption in Heterogeneous Networks (HetNets) has increased significantly resulting in problems such as higher interference among nodes, higher outage, and decreased capacity. In this paper, we propose various power allocation schemes where we allocate power among the heterogeneous user equipments. First, we propose a scheme which jointly minimizes outage probability and total power consumption in the network. Second, we devise a scheme which jointly maximizes total throughput and minimizes total power consumption. These schemes formulate multi-objective optimization problems, which are then solved using weighted sum approach. Third, we investigate a scheme to maximize energy efficiency defined as system throughput achieved per unit power consumption. Simulation results clarify the need for tradeoff among various performance parameters in practice based on device's remaining battery capacity, system outage target and quality of service (QoS) requirement in terms of signal-to-interference-plus-noise ratio (SINR). The results also show that the proposed power allocation schemes are highly efficient in attaining such tradeoffs.