Resource allocation for improving inter-cell fairness in OFDM network

Abstract

As a wireless multimedia service requires the high spectral efficiency for guaranteeing its quality of service, the femto cell which has a small cell coverage is proposed as a promising system to achieve high data rate in future wireless communication network. However, the dynamic deployment of the femto cell makes communication system be more interference limited environment. Thus, inter-cell interference is the problem that we should solve to increase the spectral efficiency. Traditional papers focus on mainly sum capacity maximization by mitigating the inter-cell interference. However, the power allocation for the maximization of the sum capacity can cause an inter-cell unfairness problem due to the difference of traffic load in each cell. In this thesis, we focus on the guarantee of inter-cell fairness with minimizing the degradation of sum capacity. To solve this problem, we formulate an optimization problem to maximize the logarithmic sum capacity subject to a total power constraint per a base station. This optimization problem considers the mitigation of the inter-cell interference and the guarantee of the inter-cell fairness at the same time in interference limited multicell multiuser OFDM network. Based on analytic results, we propose an enhanced modified iterative water-filling algorithm which improves the inter-cell fairness compared to a modified iterative water-filling algorithm. Also, to apply the enhanced modified iterative water-filling algorithm in the communication environment where the fairness is the most important rather than the sum capacity, we propose an enhanced modified iterative water-filling algorithm with fairness enhancement. We verify the effectiveness of the proposed algorithms with respect to the fairness improvement and the little degradation in the sum capacity by intensive simulations. That is, our proposed algorithms provide efficient methods to solve the inter-cell unfairness problem in the interference limited communicat...