Method for reducing feedback channel state information within adaptive OFDMA system and OFDMA system using the same

摘要

In the adaptive OFDMA systems proposed to ensure high spectral efficiency, adaptive modulation and in the case where large amount of channel state information (CSI) for each sub-carrier is fed back through the uplink to the coding (AMC), UL the occurrence of the problem of excessive use of resources. To compensate for this problem, we propose a method to reduce the channel information fed back from the adaptive OFDMA system. The present invention, adaptive in data packets transmitted and received between the base station performed by the orthogonal frequency division multiplexing scheme and the mobile station, the base station down-link data packet including the AMC ON / OFF information on whether or not there is a need to perform AMC transmitted to the mobile station via the mobile station the uplink the CSI according to the tracking result, that it is necessary to perform the AMC and performs MCS level tracking only if determined, according to the AMC oN / OFF information included in the received data packet through it characterized in that the feedback to the base station. In another aspect, the present invention, the channel state information fed back to the base station through the uplink is provided with two bits, one bit of the two bits, MCS level tracking to determine the channel condition is, the first tracking step and the second tracking divided by step it characterized in that the flag bit to be carried. Therefore, by reducing the amount of information that is fed back channel state through an uplink, and avoid unnecessary processing can prevent the waste of resources and channel resources within the computing device.