  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.
