Compensation of deteriorated CSI allocation due to fast fading and feedback delay based on turbo decision direct for MUDiv/OFDMA

Abstract

In a wireless propagation channel, the channel for each user is independent. By using this characteristic, in orthogonal frequency division multiple access (OFDMA) systems, the multiuser diversity (MUDiv) gain is obtained. However, at high Doppler frequency, since channel state information (CSI) is changed between the head and latter of packets due to the fast fading channel, the system performance is degraded. Moreover, in this case, when the feedback delay is occurred, CSI is more changed and the system performance is more degraded. To solve these problems, in this paper, we propose the compensation of the deteriorated CSI allocation due to the fast fading channel and the feedback delay based on the turbo decision direct for MUDiv/OFDMA systems.