Robust resource allocation for rates maximization using fuzzy estimation of dynamic channel states in OFDMA femtocell networks

Abstract

One of the challenging issues in dynamic resource management scheme of wireless communications is to achieve the instantaneous channel gain for transmission pairs. When designing the resource allocation algorithms, the previous works usually rely on the statistical information of the channel distribution and the harsh assumption of uncertain channel, and they are with much conservatism for the dynamic channel gain. To overcome the limitations of the existing methods, the Fuzzy Logic System (FLS) is adopted in this paper to estimate the instantaneous channel gain for the dynamic communication environments. Based on the estimated channel gains, the power allocation scheme is proposed for the orthogonal frequency division multiple access (OFDMA) femtocell network. The proposed scheme attempts to maximize the total rate of the communication system and to guarantee the quality of service of each user. The original optimization problem is a nonconvex optimization problem which is difficult to solve. The successive convex approximation (SCA) is adopted to transform the nonconvex original problem into a tractable one. The distributed iterative algorithm is developed to integrate with the proposed scheme in real-time dynamic communication environments. The effectiveness of the proposed scheme is demonstrated through the simulations, and the results show that the sum rate and energy efficiency of users can be improved by the proposed scheme, compared to the existing schemes.