Variance Based Algorithm for Grouped-Subcarrier Allocation in OFDMA Wireless Systems

Abstract

In this paper, a reduced complexity algorithm is proposed for grouped-subcarriers and power allocation in the downlink of OFDMA packet access wireless systems. The available subcarriers for data communication are grouped into partitions (groups) where each group is defined as a subchannel. The scheduler located at the base station allocates subchannels to users based on the variance of subchannel gains. The proposed algorithm for group allocation is a two-step algorithm that allocates groups to users based on the descending order of their variances to resolve the conflicting selection problem, followed by a step of fairness proportionality enhancement. To reduce the feedback burden and the complexity of the power allocation algorithm, each user feeds back the CSI on each group if the variance of gains of subcarriers inside it is less than a predefined threshold. To Show the performance of the proposed scheme, a selection of simulation results is presented.