Radio resource allocation with proportional-fair energy efficiency guarantee for smallcell networks

Abstract

This paper investigates proportional-fair energy-efficient radio resource allocation problem for the uplink transmission of OFDMA smallcell networks. Instead of the fairness measured by users' achievable data rates, this paper concentrates on the fairness in terms of energy efficiency (EE) and aims to provide EE-based proportional fairness guarantee among all users in smallcell networks. Specifically, EE-based global proportional fairness utility optimization problem is formulated, taking into account both the minimum data rates requirements and the cross-tier interference constraints. In order to make the problem more tractable, it is transformed into a weighted sum maximization problem of each user's instantaneous EE utility. Then, a two-step scheme is adopted, which solves subchannel allocation and power allocation separately, and the corresponding algorithms are devised. The proposed subchannel allocation algorithm is heuristic and low-complexity. The power allocation scheme is optimal, and is devised based on a novel method which can solve the sum of ratios problems efficiently. Numerical results verify the effectiveness of the proposed algorithms, especially the good capability of ensuring high level EE fairness among all users in the smallcell network.