Analysis of Outdated Channel State Information in Underwater Acoustic Downlink OFDMA System

作者:Qiao, Gang; Liu, Lei; Ma, Lu*
来源:OCEANS - MTS/IEEE Kobe Techno-Oceans Conference (OTO), 2018-05-28 To 2018-05-31.
DOI:10.1109/OCEANSKOBE.2018.8559440

摘要

Because of the time-varying characteristic and the large propagation delay in underwater acoustic (UWA) channel, adaptive resource allocation in UWA OFDMA system can not be performed with the assumption of perfect channel state information (CSI) at the transmitter. Therefore, this paper analyses OFDMA with outdated CSI for downlink UWA communications, and defines the per-subcarrier channel temporal correlation (PSCTC) and long-term statistical mean value as two indicators of outdated CSI, for optimizing CSI feedback in UWA channel with large propagation delay. The calculation results of PSCTC coefficient have shown the effectiveness of outdated CSI, and statistical mean values have shown the long-term stability of UWA channel. The sea trail results show that the PSCTC coefficient is related to the feedback delay, and the long-term statistics is stationary and more suitable for the adaptive resource allocation in fast time-varying channel.