Cubic spline extrapolation for uplink channel quality prediction in LTE-A with carrier aggregation

Abstract

In the context of wireless communications, an accurate channel state information is the key to a correct radio resource management. In the uplink of long-term evolution advanced, obtaining up-to-date channel state information relies on user equipments that send sounding signals throughout the available bandwidth. This procedure is quite challenging when considering the ever increasing bandwidth demands and the introduction of carrier aggregation. Information from many radio resource blocks becomes outdated and unreliable for scheduling operations. Besides, interference values are much more variant than in the downlink due to changes in the position of interferers and their transmission power. This work proposes the introduction of a cubic spline extrapolation method to obtain a prediction horizon that allows extending the reliability of the channel quality evaluation along time. Although very high interference levels and variations thereof imply no gains, the mechanism succeeds with moderate interference, situation that can be provided by interference cancellation strategies.