Adaptive transmission techniques, such as adaptive modulation and coding, adaptive power control, adaptive transmitter antenna diversity, etc., generally require precise channel estimation and channel state information (CSI) feedback. For fast vehicle speeds, reliable adaptive transmission also requires prediction of future CSI since the channel conditions are rapidly time-variant. We propose to use past channel observations of one carrier to predict future CSI and perform adaptive modulation without feedback for another correlated carrier. A statistical model of the prediction error that depends on the frequency and time correlation is developed and is used in the design of reliable adaptive modulation methods. Significant gains relative to non-adaptive techniques are demonstrated for sufficiently correlated channels and realistic prediction range.
['Tung-Sheng Yang', 'Alexandra Duel-Hallen']
Adaptive modulation using outdated samples of another fading channel