An efficient resource allocation scheme with partial Channel State Information

The proposed resource allocation scheme can boost the spectral efficiency of multi-user OFDMA wireless systems with heterogeneous delay requirements. The existing designs usually have two important assumptions that the users are delay insensitive and Channel State Information at the Transmitter (CSI) is perfect. In practice, users have heterogeneous delay requirements and CSI usually becomes outdated in time varying channel, which in turn leads to systematic packet errors and hence results in significant degradation on the throughput. CSI at the physical layer and scheduling using queuing theory at the Medium Access Control (MAC) layer, in order to maximize the throughput and spectral efficiency under the heterogeneous delay constraints. In this paper we study the effect of the imperfect channel state information (CSI) on the performance of adaptive orthogonal frequency division multiple access (OFDMA) systems. To perform resource allocation, CSI must be fed back to the transmitter. Such feedback CSI is always imperfect due to the time varying channel.